diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml index 76578ab..f4496be 100644 --- a/.github/workflows/ci.yml +++ b/.github/workflows/ci.yml @@ -4,12 +4,10 @@ on: [push, pull_request] jobs: test: runs-on: ubuntu-latest - permissions: - contents: read strategy: matrix: entry: - - { ruby: '2.7.0', allowed-failure: false } # Minimum supported Ruby version. + - { ruby: '2.7', allowed-failure: false } - { ruby: '3.0', allowed-failure: false } - { ruby: '3.1', allowed-failure: false } - { ruby: '3.2', allowed-failure: false } @@ -19,7 +17,7 @@ jobs: - { ruby: 'head', allowed-failure: true } name: Test Ruby ${{ matrix.entry.ruby }} steps: - - uses: actions/checkout@v7 + - uses: actions/checkout@v6 - uses: ruby/setup-ruby@v1 with: ruby-version: ${{ matrix.entry.ruby }} @@ -29,11 +27,9 @@ jobs: rubocop: runs-on: ubuntu-latest - permissions: - contents: read name: RuboCop steps: - - uses: actions/checkout@v7 + - uses: actions/checkout@v6 - uses: ruby/setup-ruby@v1 with: ruby-version: 4.0 # Specify the latest supported Ruby version. @@ -42,11 +38,9 @@ jobs: yard: runs-on: ubuntu-latest - permissions: - contents: read name: YARD Documentation steps: - - uses: actions/checkout@v7 + - uses: actions/checkout@v6 - uses: ruby/setup-ruby@v1 with: ruby-version: 4.0 # Specify the latest supported Ruby version. diff --git a/.github/workflows/conformance.yml b/.github/workflows/conformance.yml deleted file mode 100644 index ff178c2..0000000 --- a/.github/workflows/conformance.yml +++ /dev/null @@ -1,29 +0,0 @@ -name: Conformance Tests - -on: - push: - branches: [main] - pull_request: - workflow_dispatch: - -concurrency: - group: conformance-${{ github.ref }}-${{ github.event_name == 'push' && github.sha || '' }} - cancel-in-progress: true - -permissions: - contents: read - -jobs: - server-conformance: - runs-on: ubuntu-latest - continue-on-error: true - steps: - - uses: actions/checkout@v7 - - uses: ruby/setup-ruby@v1 - with: - ruby-version: '4.0' # Specify the latest supported Ruby version. - bundler-cache: true - - uses: actions/setup-node@v7 - with: - node-version: '24' # Specify the latest Node.js version. - - run: bundle exec rake conformance:test diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml index e343d22..32e7957 100644 --- a/.github/workflows/release.yml +++ b/.github/workflows/release.yml @@ -16,7 +16,7 @@ jobs: id-token: write # IMPORTANT: this permission is mandatory for trusted publishing contents: write # IMPORTANT: this permission is required for `rake release` to push the release tag steps: - - uses: actions/checkout@v7 + - uses: actions/checkout@v6 - name: Set up Ruby uses: ruby/setup-ruby@v1 with: @@ -34,7 +34,7 @@ jobs: contents: write steps: - - uses: actions/checkout@v7 + - uses: actions/checkout@v6 with: fetch-depth: 0 # Fetch all history for all branches and tags diff --git a/.gitignore b/.gitignore index de8444e..750a5a9 100644 --- a/.gitignore +++ b/.gitignore @@ -1,5 +1,4 @@ .ruby-version -/*.gem /.bundle/ /.yardoc /_yardoc/ @@ -9,7 +8,3 @@ /spec/reports/ /tmp/ Gemfile.lock -docs/_site/ -docs/.jekyll-cache/ -docs/.jekyll-metadata -docs/_data/versions.yml diff --git a/.rubocop.yml b/.rubocop.yml index aefa67a..2120de4 100644 --- a/.rubocop.yml +++ b/.rubocop.yml @@ -7,17 +7,9 @@ plugins: AllCops: TargetRubyVersion: 2.7 - SuggestExtensions: false Gemspec/DevelopmentDependencies: Enabled: true -Lint/IncompatibleIoSelectWithFiberScheduler: - Enabled: true - Minitest/LiteralAsActualArgument: Enabled: true - -Naming/MethodName: - AllowedPatterns: - - '\Atest_' diff --git a/AGENTS.md b/AGENTS.md index 6635c3b..6b269d7 100644 --- a/AGENTS.md +++ b/AGENTS.md @@ -15,9 +15,7 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing - `bundle install` - Install dependencies - `rake test` - Run all tests - `rake rubocop` - Run linter -- `rake` - Run linting, tests, and the conformance suite (default task) -- `bundle exec rake conformance:test` - Run the MCP conformance suite (see conformance/README.md) -- `bundle exec rake docs:preview` - Serve the documentation site locally at http://localhost:4000 (PORT to override) +- `rake` - Run tests and linting (default task) - `ruby -I lib -I test test/path/to/specific_test.rb` - Run single test file - `gem build mcp.gemspec` - Build the gem @@ -34,15 +32,6 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing - Use frozen string literals - Follow Ruby community conventions - Keep dependencies minimal -- Use lowercase HTTP response header names (e.g. `mcp-session-id`); the Rack 3 SPEC requires this, and the MCP spec's `Mcp-Session-Id` casing is prose convention only - -## Documentation - -- User-facing documentation lives in `docs/`, one page per topic, published at https://ruby.sdk.modelcontextprotocol.io (deploys only when a release is published) -- Pages live in the `docs/_server/`, `docs/_client/`, and `docs/_extensions/` collections -- Keep README.md slim: quick start and pointers only; document features on the relevant docs page -- Internal links are absolute and extensionless (e.g. `/server/tools/`); front matter is followed by a blank line before the h1 -- Callout tiers: `.note` (supplementary), `.important` (spec constraints), `.warning` (deprecated features) ## Commit message conventions @@ -67,18 +56,12 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing **MCP::Server** (`lib/mcp/server.rb`): -- Main server class handling JSON-RPC requests and holding shared configuration (tools, prompts, resources, handlers, capabilities) +- Main server class handling JSON-RPC requests - Implements MCP protocol methods: initialize, ping, tools/list, tools/call, prompts/list, prompts/get, resources/list, resources/read - Supports custom method registration via `define_custom_method` - Handles instrumentation, exception reporting, and notifications - Uses JsonRpcHandler for request processing -**MCP::ServerSession** (`lib/mcp/server_session.rb`): - -- Per-connection state: client info, logging level -- Created by the transport layer for each client connection -- Delegates request handling to the shared `Server` - **MCP::Client** (`lib/mcp/client.rb`): - Client interface for communicating with MCP servers @@ -112,14 +95,6 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing - Protocol version 2025-03-26+ supports tool annotations (destructive_hint, idempotent_hint, etc.) - Validation is configurable via `configuration.validate_tool_call_arguments` -**Session Architecture**: - -- `Server` holds shared configuration (tools, prompts, resources, handlers) -- `ServerSession` holds per-connection state (client info, logging level) -- Both `StdioTransport` and `StreamableHTTPTransport` create a `ServerSession` per connection, making the session model transparent across transports -- Session-scoped notifications (`notify_progress`, `notify_log_message`) are sent only to the originating client via `ServerSession` -- Server-wide notifications (`notify_tools_list_changed`, etc.) broadcast to all sessions via `Server` - **Context Passing**: - `server_context` hash passed through tool/prompt calls for request-specific data @@ -127,6 +102,6 @@ This is the official Ruby SDK for the Model Context Protocol (MCP), implementing ### Integration patterns -- **Rails/Rack apps**: Mount `StreamableHTTPTransport` as a Rack app (e.g., `mount transport => "/mcp"`) +- **Rails controllers**: Use `server.handle_json(request.body.read)` for HTTP endpoints - **Command-line tools**: Use `StdioTransport.new(server).open` for CLI applications -- **HTTP services**: Use `StreamableHTTPTransport` for web-based servers +- **HTTP services**: Use `StreamableHttpTransport` for web-based servers diff --git a/CHANGELOG.md b/CHANGELOG.md index 88ec62e..1600b2c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -7,475 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ## [Unreleased] -## [1.5.1] - 2026-09-09 - -This release keeps the HTTP client working with json 3.0. That release accepts the options of `JSON.parse` -as keywords only, and Faraday's JSON response middleware, through 2.14.3, passes them as a positional Hash, -which Ruby 3 no longer converts, so every JSON body the client received failed as an internal error. -The client now parses response bodies itself, the way it already handled streamed ones, and no longer -registers the middleware. A malformed JSON body delivered whole by an adapter without streaming support -now raises `RequestHandlerError` with `error_type: :parse_error`, as the streamed path already did. - -### Fixed - -- Parse HTTP client response bodies without Faraday's JSON middleware, which json 3.0 breaks (#546) - -## [1.5.0] - 2026-09-05 - -This release makes the client answer a server's `ping` with the empty result the specification requires. -Earlier clients replied with Method not found over Streamable HTTP and stayed silent over stdio, -so a server that checks liveness dropped their long-lived sessions. On the OAuth side, -the embedding application can refuse an authorization request through `authorization_request_validator`, -and stored tokens are refreshed only against the authorization server that issued them: -when the server named for a session differs, the client reauthorizes instead of refreshing, -and the validator sees the newly named server. Tokens stored by earlier releases carry no issuer and keep refreshing. - -### Added - -- Add `authorization_request_validator` to let the embedding application refuse an authorization request (#539) - -### Fixed - -- Answer server-to-client pings in the client (#541) - -## [1.4.0] - 2026-08-28 - -This release repairs the `subscriptions/listen` stream. A host that buffers its responses, -the documented Rails controller pattern among them, can decline the method with -`serve_subscriptions_listen: false` instead of answering a modern client with a streaming body -it cannot render, and the stream's ordering guarantees are enforced: no notification reaches -a client before the acknowledgement, and none follows the graceful closing result. - -### Added - -- Add `serve_subscriptions_listen:` for hosts that cannot hold an SSE stream open (#533) - -### Fixed - -- Deliver `subscriptions/listen` notifications only after the acknowledgement (#532) -- Serialize `subscriptions/listen` writes so the graceful result is the final message (#535) - -## [1.3.0] - 2026-08-22 - -User-facing documentation now lives on the documentation site at https://ruby.sdk.modelcontextprotocol.io, -and README.md keeps the quick start. Two entries under "Changed" reject traffic that earlier releases accepted -and ship in a minor release under the exceptions described in [VERSIONING.md](VERSIONING.md). - -### Added - -- Add a `resources_list_handler` for context-dependent resource lists (#509) -- Pass a handler-returned `_meta` through the subscribe result (#510) - -### Changed - -- Bound OAuth response bodies in the client (#520) -- Reject duplicate in-flight JSON-RPC request ids (#521) -- Move the documentation from README.md to the documentation site (#523) - -## [1.2.0] - 2026-08-15 - -This release completes the SEP-2575 stateless lifecycle of the 2026-07-28 specification, together with -the SEP-2322, SEP-2549, and SEP-2243 features that revision builds on. Several entries under "Changed" -are incompatible with 1.1.0 and ship in a minor release under the spec-conformance and security exceptions -described in [VERSIONING.md](VERSIONING.md). - -### Added - -- Handle the SEP-2575 modern request envelope in the server core (#475) -- Serve both lifecycle eras over stdio with an era lock per SEP-2575 (#478) -- Serve the sessionless modern path over Streamable HTTP per SEP-2575 (#479) -- Finalize `server/discover` and add client modern lifecycle support per SEP-2575 (#480) -- Let handlers return multi round-trip `input_required` results per SEP-2322 (#481) -- Add `MCP::Elicitation::EnumSchema` builders per SEP-1330 (#482) -- Stamp the required `resultType` on modern results per SEP-2322 (#487) -- Enforce the modern lifecycle admission rules per SEP-2575 (#489) -- Stream modern request notifications and honor the envelope `logLevel` per SEP-2575 (#490) -- Expose the user-defined `server_context` in instrumentation data (#493) -- Serve the `subscriptions/listen` notification stream per SEP-2575 (#495) -- Add opt-in `requestState` sealing via `MCP::Server::RequestStateSecurity` (#496) -- Mirror `x-mcp-header` tool parameters into `Mcp-Param-*` headers per SEP-2243 (#498) -- Stamp the required cache hints on modern cacheable results per SEP-2549 (#499) -- Drive multi round-trip `input_required` results on the client per SEP-2322 (#500) -- Fulfill `input_required` results on the legacy wire per SEP-2322 (#501) - -### Changed - -- Align modern envelope validation with the finalized specification (#491) -- Require the `Mcp-Method` header on the modern path (#492) -- Bound server-to-client requests with a timeout (#502) -- Refuse server-to-client requests in the modern lifecycle per SEP-2575 (#503) -- Bound the total wait across SSE reconnection attempts (#504) -- Bound automatic pagination in the MCP client (#505) -- Reject modern-removed methods before the connection era locks (#511) -- Stop negotiating modern protocol versions through the `initialize` handshake (#516) - -### Deprecated - -- Warn on modern client connects that declare the Roots or Sampling capabilities deprecated per SEP-2577 (#406, #516) - -### Fixed - -- Stop leaking exception messages to clients via JSON-RPC error data (#486) -- Return Invalid Params for unknown prompts and missing prompt arguments (#517) -- Restrict OAuth discovery to same-origin metadata URLs and refuse private-network destinations - -## [1.1.0] - 2026-08-01 - -### Added - -- Support 2026-07-28 as the Latest Protocol Version (#476) -- Expose server tool annotations on MCP::Client::Tool (#445) - -### Fixed - -- Preserve explicit tool response content (#469) - -## [1.0.0] - 2026-07-24 - -First stable release. The public API is now stable: breaking changes ship only in major releases, -apart from the narrow exceptions documented in [VERSIONING.md](VERSIONING.md). - -### Added - -- Add `ROADMAP.md` outlining the path toward SEP-1730 (#465) -- Add `VERSIONING.md` documenting the versioning and breaking-change policy (#466) - -## [0.25.0] - 2026-07-18 - -### Added - -- Support SEP-990 Cross-App Access via ID-JAG and the `jwt-bearer` grant (#454) -- Support client-side sampling via `MCP::Client#on_sampling` (#458) - -### Fixed - -- Reject notifications carrying an unknown or expired session (#455) -- Handle an `initialize` request sent without an ID (#456) -- Bound client-side message buffering in the HTTP transport (#459) -- Lowercase response header names in `StreamableHTTPTransport` (#460) - -## [0.24.0] - 2026-07-12 - -### Added - -- Support SSE reconnection per SEP-1699 in the HTTP client transport (#426) -- Validate the RFC 9207 `iss` authorization response parameter per SEP-2468 (#431) -- Support `private_key_jwt` client authentication for the `client_credentials` grant (#432) -- Recognize multi round-trip `input_required` results per SEP-2322 (#433) -- Add opt-in `ttlMs` / `cacheScope` cache hints to List and Read results per SEP-2549 (#436) -- Add `server/discover` and stateless lifecycle error codes per SEP-2575 (#438) -- Associate server-to-client requests with the originating client request per SEP-2260 (#440) -- Add server-side MCP Apps helpers per SEP-1865 (#441) -- Support client-side elicitation with SEP-1034 schema defaults (#443) -- Support class-based Resource and ResourceTemplate definitions (#447) - -### Changed - -- Bind stored client credentials to the authorization server issuer per SEP-2352 (#439) - -### Fixed - -- Handle non-object JSON-RPC messages without raising (#448) -- Perform SSE stream writes outside the session mutex (#449) -- Validate required params for `initialize` and `resources/subscribe` (#451) - -## [0.23.0] - 2026-07-07 - -### Added - -- Add a session-ownership hook to `StreamableHTTPTransport` - -### Changed - -- Require calling `MCP::Client#connect` before sending requests on stdio transport (#427) - -### Deprecated - -- Annotate Roots, Sampling, and Logging APIs as deprecated per SEP-2577 (#429) - -### Fixed - -- Fix an incorrect `result: null` response to an id-bearing notification message (#435) -- Validate `Host` and `Origin` headers to prevent DNS rebinding per MCP 2025-11-25 -- Bound stateful session retention to prevent an initialize-flood DoS -- Bound stdio frame reads with `max_line_bytes` -- Bound request body and frame reads to prevent memory-exhaustion DoS - -## [0.22.0] - 2026-06-27 - -### Added - -- Add `audience` role validation for `MCP::Annotations` per MCP specification (#422) -- Send SEP-2243 `Mcp-Method` and `Mcp-Name` headers per MCP specification (#423) -- Support client-side `notifications/cancelled` per MCP specification (#425) - -### Changed - -- Conform Tool Schemas to JSON Schema 2020-12 per SEP-2106 (#417) - -### Fixed - -- Fix a `SyntaxError` on Ruby 2.7.0 caused by arguments forwarding syntax (#419) - -## [0.21.0] - 2026-06-20 - -### Added - -- Support capability extensions per SEP-2133 (#405) -- Add range validation for `MCP::Annotations#priority` per MCP specification (#410) -- Isolate stateless requests in ephemeral sessions per SEP-2567 (#415) - -### Changed - -- Set OIDC `application_type` on Dynamic Client Registration per SEP-837 (#408) -- Fall back to legacy 2025-03-26 OAuth discovery for servers without PRM (#414) - -## [0.20.0] - 2026-06-14 - -### Added - -- Support W3C Trace Context Propagation via `_meta` per SEP-414 (#397) -- Support OAuth `client_credentials` grant in OAuth client (#399) -- Add `annotations` field to `MCP::Resource` and `MCP::ResourceTemplate` per MCP specification (#403) - -### Changed - -- Re-run OAuth flow on 403 `insufficient_scope` (step-up) (#368) -- Speed up `Tool::Schema` validation by 5x to 100x (#369) -- Use JSON-RPC error envelope for `StreamableHTTPTransport` errors (#371) -- Pin RFC 8414 default well-known suffix per SEP-2351 (#395) -- Default missing `MCP-Protocol-Version` to `2025-03-26` in `StreamableHTTPTransport` (#392) - -### Fixed - -- Preserve the request ID in invalid request error responses (#400) -- Standardize Resource Not Found errors on -32602 with URI data per SEP-2164 (#402) - -## [0.19.0] - 2026-06-13 - -### Added - -- Support Client ID Metadata Documents in OAuth client (#361) -- Request `offline_access` scope when supported (#365) -- Add `size` field to `MCP::Resource` per MCP specification (#393) - -## [0.18.0] - 2026-05-30 - -### Added - -- Support server-to-client `ping` per MCP specification (#358) - -### Changed - -- Warn on implicit stdio initialization (#338) -- Cache `Tool::Schema` validation to avoid re-validating identical schemas (#363) - -### Fixed - -- Fix case-sensitive `Accept` header comparison (#359) - -## [0.17.0] - 2026-05-19 - -### Added - -- Add OAuth 2.1 client support for MCP authorization flow (#353) - -### Fixed - -- Validate `MCP-Protocol-Version` header in `StreamableHTTPTransport` (#347) -- Reject duplicate `initialize` requests (#350) -- Reject non-Hash JSON-RPC bodies in `StreamableHTTPTransport` (#354) - -## [0.16.0] - 2026-05-14 - -### Added - -- Add opt-in tool output validation (#344) - -### Changed - -- Advertise JSON Schema 2020-12 dialect on emitted tool schemas (#342) - -### Fixed - -- Preserve client tool output schemas (#343) -- Fix missing `output_schema` argument in `define_tool` API (#301) - -## [0.15.0] - 2026-05-05 - -### Added - -- Support `notifications/cancelled` per MCP specification (#332) -- Add client-level `connect` for initialize handshake (#327) -- Add client-level `connect` handshake to stdio transport (#336) - -### Changed - -- Return tool argument validation failures as tool execution errors (#333) - -### Removed - -- Remove obsolete `MCP::Transports` module (#331) - -## [0.14.0] - 2026-04-24 - -### Added - -- Support pagination per MCP specification (#320) -- Support resource subscriptions per MCP specification (#313) -- Add `roots/list` and `notifications/roots/list_changed` support (#315) -- Support JSON response mode for `StreamableHTTPTransport` (#328) -- Add HTTP client close for explicit session termination (#326) -- Track `Mcp-Session-Id` and protocol version in HTTP client (#325) -- Support `ping` client API per MCP specification (#324) - -### Fixed - -- Handle 202 Accepted response in HTTP client (#323) - -### Changed - -- Parse SSE responses in HTTP client via `event_stream_parser` (#322) - -## [0.13.0] - 2026-04-16 - -### Added - -- Make `StreamableHTTPTransport` a Rack application (#263) -- Support `elicitation/create` per MCP specification (#312) -- Add `around_request` hook for request instrumentation (#309) -- Add `_meta` field to resource, content, and result classes (#310) - -### Removed - -- Remove `Server#create_sampling_message` direct call (#311) - -## [0.12.0] - 2026-04-11 - -### Added - -- Support customizing the Faraday client in `MCP::Client::HTTP` (#306) - -### Changed - -- Auto-set `server.transport` in `Transport#initialize` (#305) - -### Fixed - -- Validate Content-Type on POST requests (#304) - -## [0.11.0] - 2026-04-06 - -### Added - -- Support `sampling/createMessage` per MCP specification (#282) -- Support `completion/complete` per MCP specification (#289) - -### Fixed - -- Support POST response SSE streams for server-to-client messages (#294) -- Return protocol errors for invalid arguments and server errors (#285) -- Fix client methods silently swallowing JSON-RPC error responses (#281) -- Close streams outside mutex in session cleanup (#291) - -## [0.10.0] - 2026-03-30 - -### Added - -- Session expiry controls for `StreamableHTTPTransport` via `session_idle_timeout:` option (#268) - -### Changed - -- `ServerSession` for per-connection state (#275) - -### Removed - -- Remove `Server#notify_progress` broadcast API (#276) -- Remove undocumented handler override methods (#270) - -### Fixed - -- Reject POST requests without session ID in stateful mode (#274) - -## [0.9.2] - 2026-03-27 - -### Fixed - -- Use accessor method in `server_context_with_meta` instead of ivar (#273) -- Reject duplicate SSE connections with 409 to prevent stream hijacking - -## [0.9.1] - 2026-03-23 - -### Added - -- Allow `Client#call_tool` to accept a tool name (#266) - -### Fixed - -- Return 404 for invalid session ID in `handle_delete` (#261) - -## [0.9.0] - 2026-03-20 - -### Added - -- `MCP::Client::Stdio` transport (#262) -- Progress notifications per MCP specification (#254) -- Automatic `_meta` parameter extraction support (#172) -- CORS and Accept wildcard support for browser-based MCP clients (#253) - -### Changed - -- Use `autoload` to defer loading of unused subsystems (#255) -- Reduce release package size (#239) - -### Fixed - -- Return 404 for invalid session ID in `handle_regular_request` (#257) -- Use mutex-protected `session_exists?` in `handle_regular_request` (#258) - -## [0.8.0] - 2026-03-03 - -### Added - -- `Content::EmbeddedResource` class for embedded resource content type (#244) -- `Content::Audio` class for audio content type (#243) -- `$ref` support in `Tool::Schema` for protocol version 2025-11-25 (#242) -- MCP conformance test suite (#248) - -### Fixed - -- Handle `Errno::ECONNRESET` in SSE stream operations (#249) -- Fix default handler return values to comply with MCP spec (#247) -- Fix `Prompt#validate_arguments!` crash when arguments are `nil` (#246) -- Return 202 Accepted for SSE responses per MCP spec (#245) -- Fix `Content::Image#to_h` to return `mimeType` (camelCase) per MCP spec (#241) - -## [0.7.1] - 2026-02-21 - -### Fixed - -- Fix `Resource::Contents#to_h` to use correct property names per MCP spec (#235) -- Return JSON-RPC protocol errors for unknown tool calls (#231) -- Fix `logging/setLevel` to return empty hash per MCP specification (#230) - -## [0.7.0] - 2026-02-14 - -### Added - -- `logging` support (#103) -- Protocol version negotiation to server initialization (#223) -- Tool arguments to instrumentation data (#218) -- Client info to instrumentation callback (#221) -- `resource_templates` to `MCP::Client` (#225) - -### Changed - -- Extract `MCP::Annotations` into a dedicated file (#224) - -### Fixed - -- `Resource::Embedded` not setting `@resource` in `initialize` (#220) - ## [0.6.0] - 2026-01-16 ### Changed @@ -591,4 +122,4 @@ apart from the narrow exceptions documented in [VERSIONING.md](VERSIONING.md). ## [0.1.0] - 2025-05-30 -Initial release in collaboration with Shopify +Initial release diff --git a/CLAUDE.md b/CLAUDE.md deleted file mode 100644 index 43c994c..0000000 --- a/CLAUDE.md +++ /dev/null @@ -1 +0,0 @@ -@AGENTS.md diff --git a/Gemfile b/Gemfile index 0aa50ee..fa2d2b8 100644 --- a/Gemfile +++ b/Gemfile @@ -6,26 +6,22 @@ source "https://rubygems.org" gemspec # Specify development dependencies below -gem "rubocop-minitest", ">= 0.39.0", require: false +gem "rubocop-minitest", require: false gem "rubocop-rake", require: false gem "rubocop-shopify", ">= 2.18", require: false if RUBY_VERSION >= "3.1" gem "puma", ">= 5.0.0" -gem "rack-cors" gem "rackup", ">= 2.1.0" gem "activesupport" # Fix io-console install error when Ruby 3.0. gem "debug" if RUBY_VERSION >= "3.1" -# Avoid i18n 1.15.0, which breaks on Ruby 3.1 (ruby-i18n/i18n#735). -gem "i18n", "!= 1.15.0" gem "rake", "~> 13.0" gem "sorbet-static-and-runtime" if RUBY_VERSION >= "3.0" gem "yard", "~> 0.9" gem "yard-sorbet", "~> 0.9" if RUBY_VERSION >= "3.1" group :test do - gem "event_stream_parser", ">= 1.0" gem "faraday", ">= 2.0" gem "minitest", "~> 5.1", require: false gem "mocha" diff --git a/README.md b/README.md index 7a71fb2..8e3ec4d 100644 --- a/README.md +++ b/README.md @@ -2,21 +2,12 @@ The official Ruby SDK for Model Context Protocol servers and clients. -Detailed guides are available at https://ruby.sdk.modelcontextprotocol.io. - -## Features - -- Build [MCP servers](https://ruby.sdk.modelcontextprotocol.io/server/) that expose tools, prompts, and resources to any MCP host -- Build [MCP clients](https://ruby.sdk.modelcontextprotocol.io/client/) that connect to any MCP server, with automatic lifecycle negotiation and OAuth 2.1 authorization -- Speak every standard transport: stdio and Streamable HTTP (including SSE), with a Rails integration -- Cover the full protocol surface: server-to-client requests, multi round-trip requests, notifications, progress, logging, cancellation, completions, and pagination - ## Installation Add this line to your application's Gemfile: ```ruby -gem "mcp" +gem 'mcp' ``` And then execute: @@ -33,14 +24,170 @@ $ gem install mcp You may need to add additional dependencies depending on which features you wish to access. -## Quick Start +## Building an MCP Server -The following minimal programs show both sides of the protocol: a server that exposes a single tool, -and a client that spawns such a server and drives it over stdio. +The `MCP::Server` class is the core component that handles JSON-RPC requests and responses. +It implements the Model Context Protocol specification, handling model context requests and responses. -### MCP Server +### Key Features -A minimal server defines a tool and serves it over the stdio transport: +- Implements JSON-RPC 2.0 message handling +- Supports protocol initialization and capability negotiation +- Manages tool registration and invocation +- Supports prompt registration and execution +- Supports resource registration and retrieval +- Supports stdio & Streamable HTTP (including SSE) transports +- Supports notifications for list changes (tools, prompts, resources) + +### Supported Methods + +- `initialize` - Initializes the protocol and returns server capabilities +- `ping` - Simple health check +- `tools/list` - Lists all registered tools and their schemas +- `tools/call` - Invokes a specific tool with provided arguments +- `prompts/list` - Lists all registered prompts and their schemas +- `prompts/get` - Retrieves a specific prompt by name +- `resources/list` - Lists all registered resources and their schemas +- `resources/read` - Retrieves a specific resource by name +- `resources/templates/list` - Lists all registered resource templates and their schemas + +### Custom Methods + +The server allows you to define custom JSON-RPC methods beyond the standard MCP protocol methods using the `define_custom_method` method: + +```ruby +server = MCP::Server.new(name: "my_server") + +# Define a custom method that returns a result +server.define_custom_method(method_name: "add") do |params| + params[:a] + params[:b] +end + +# Define a custom notification method (returns nil) +server.define_custom_method(method_name: "notify") do |params| + # Process notification + nil +end +``` + +**Key Features:** + +- Accepts any method name as a string +- Block receives the request parameters as a hash +- Can handle both regular methods (with responses) and notifications +- Prevents overriding existing MCP protocol methods +- Supports instrumentation callbacks for monitoring + +**Usage Example:** + +```ruby +# Client request +{ + "jsonrpc": "2.0", + "id": 1, + "method": "add", + "params": { "a": 5, "b": 3 } +} + +# Server response +{ + "jsonrpc": "2.0", + "id": 1, + "result": 8 +} +``` + +**Error Handling:** + +- Raises `MCP::Server::MethodAlreadyDefinedError` if trying to override an existing method +- Supports the same exception reporting and instrumentation as standard methods + +### Notifications + +The server supports sending notifications to clients when lists of tools, prompts, or resources change. This enables real-time updates without polling. + +#### Notification Methods + +The server provides three notification methods: + +- `notify_tools_list_changed` - Send a notification when the tools list changes +- `notify_prompts_list_changed` - Send a notification when the prompts list changes +- `notify_resources_list_changed` - Send a notification when the resources list changes + +#### Notification Format + +Notifications follow the JSON-RPC 2.0 specification and use these method names: + +- `notifications/tools/list_changed` +- `notifications/prompts/list_changed` +- `notifications/resources/list_changed` + +#### Transport Support + +- **stdio**: Notifications are sent as JSON-RPC 2.0 messages to stdout +- **Streamable HTTP**: Notifications are sent as JSON-RPC 2.0 messages over HTTP with streaming (chunked transfer or SSE) + +#### Usage Example + +```ruby +server = MCP::Server.new(name: "my_server") + +# Default Streamable HTTP - session oriented +transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) + +server.transport = transport + +# When tools change, notify clients +server.define_tool(name: "new_tool") { |**args| { result: "ok" } } +server.notify_tools_list_changed +``` + +You can use Stateless Streamable HTTP, where notifications are not supported and all calls are request/response interactions. +This mode allows for easy multi-node deployment. +Set `stateless: true` in `MCP::Server::Transports::StreamableHTTPTransport.new` (`stateless` defaults to `false`): + +```ruby +# Stateless Streamable HTTP - session-less +transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, stateless: true) +``` + +### Unsupported Features (to be implemented in future versions) + +- Log Level +- Resource subscriptions +- Completions +- Elicitation + +### Usage + +#### Rails Controller + +When added to a Rails controller on a route that handles POST requests, your server will be compliant with non-streaming +[Streamable HTTP](https://modelcontextprotocol.io/specification/latest/basic/transports#streamable-http) transport +requests. + +You can use the `Server#handle_json` method to handle requests. + +```ruby +class ApplicationController < ActionController::Base + def index + server = MCP::Server.new( + name: "my_server", + title: "Example Server Display Name", + version: "1.0.0", + instructions: "Use the tools of this server as a last resort", + tools: [SomeTool, AnotherTool], + prompts: [MyPrompt], + server_context: { user_id: current_user.id }, + ) + render(json: server.handle_json(request.body.read)) + end +end +``` + +#### Stdio Transport + +If you want to build a local command-line application, you can use the stdio transport: ```ruby require "mcp" @@ -76,64 +223,752 @@ transport = MCP::Server::Transports::StdioTransport.new(server) transport.open ``` -Save the script as `server.rb`, run it, and send JSON-RPC requests via stdin: +You can run this script and then type in requests to the server at the command line. ```console -$ ruby server.rb +$ ruby examples/stdio_server.rb {"jsonrpc":"2.0","id":"1","method":"ping"} {"jsonrpc":"2.0","id":"2","method":"tools/list"} {"jsonrpc":"2.0","id":"3","method":"tools/call","params":{"name":"example_tool","arguments":{"message":"Hello"}}} ``` -The same server can also run over Streamable HTTP, including mounted inside a Rails application; -see [Server Transports](https://ruby.sdk.modelcontextprotocol.io/server/transports/). +### Configuration -### MCP Client - -A minimal client spawns a stdio server as a subprocess, connects, and lists and calls its tools: +The gem can be configured using the `MCP.configure` block: ```ruby -stdio_transport = MCP::Client::Stdio.new( - command: "bundle", - args: ["exec", "ruby", "path/to/server.rb"], - env: { "API_KEY" => "my_secret_key" }, - read_timeout: 30 +MCP.configure do |config| + config.exception_reporter = ->(exception, server_context) { + # Your exception reporting logic here + # For example with Bugsnag: + Bugsnag.notify(exception) do |report| + report.add_metadata(:model_context_protocol, server_context) + end + } + + config.instrumentation_callback = ->(data) { + puts "Got instrumentation data #{data.inspect}" + } +end +``` + +or by creating an explicit configuration and passing it into the server. +This is useful for systems where an application hosts more than one MCP server but +they might require different instrumentation callbacks. + +```ruby +configuration = MCP::Configuration.new +configuration.exception_reporter = ->(exception, server_context) { + # Your exception reporting logic here + # For example with Bugsnag: + Bugsnag.notify(exception) do |report| + report.add_metadata(:model_context_protocol, server_context) + end +} + +configuration.instrumentation_callback = ->(data) { + puts "Got instrumentation data #{data.inspect}" +} + +server = MCP::Server.new( + # ... all other options + configuration:, ) -client = MCP::Client.new(transport: stdio_transport) +``` -# Perform the MCP initialization handshake before sending any requests. -client.connect +### Server Context and Configuration Block Data -# List available tools. -tools = client.tools -tools.each do |tool| - puts "Tool: #{tool.name} - #{tool.description}" +#### `server_context` + +The `server_context` is a user-defined hash that is passed into the server instance and made available to tools, prompts, and exception/instrumentation callbacks. It can be used to provide contextual information such as authentication state, user IDs, or request-specific data. + +**Type:** + +```ruby +server_context: { [String, Symbol] => Any } +``` + +**Example:** + +```ruby +server = MCP::Server.new( + name: "my_server", + server_context: { user_id: current_user.id, request_id: request.uuid } +) +``` + +This hash is then passed as the `server_context` argument to tool and prompt calls, and is included in exception and instrumentation callbacks. + +#### Configuration Block Data + +##### Exception Reporter + +The exception reporter receives: + +- `exception`: The Ruby exception object that was raised +- `server_context`: The context hash provided to the server + +**Signature:** + +```ruby +exception_reporter = ->(exception, server_context) { ... } +``` + +##### Instrumentation Callback + +The instrumentation callback receives a hash with the following possible keys: + +- `method`: (String) The protocol method called (e.g., "ping", "tools/list") +- `tool_name`: (String, optional) The name of the tool called +- `prompt_name`: (String, optional) The name of the prompt called +- `resource_uri`: (String, optional) The URI of the resource called +- `error`: (String, optional) Error code if a lookup failed +- `duration`: (Float) Duration of the call in seconds + +**Type:** + +```ruby +instrumentation_callback = ->(data) { ... } +# where data is a Hash with keys as described above +``` + +**Example:** + +```ruby +config.instrumentation_callback = ->(data) { + puts "Instrumentation: #{data.inspect}" +} +``` + +### Server Protocol Version + +The server's protocol version can be overridden using the `protocol_version` keyword argument: + +```ruby +configuration = MCP::Configuration.new(protocol_version: "2024-11-05") +MCP::Server.new(name: "test_server", configuration: configuration) +``` + +If no protocol version is specified, the latest stable version will be applied by default. +The latest stable version includes new features from the [draft version](https://modelcontextprotocol.io/specification/draft). + +This will make all new server instances use the specified protocol version instead of the default version. The protocol version can be reset to the default by setting it to `nil`: + +```ruby +MCP::Configuration.new(protocol_version: nil) +``` + +If an invalid `protocol_version` value is set, an `ArgumentError` is raised. + +Be sure to check the [MCP spec](https://modelcontextprotocol.io/specification/versioning) for the protocol version to understand the supported features for the version being set. + +### Exception Reporting + +The exception reporter receives two arguments: + +- `exception`: The Ruby exception object that was raised +- `server_context`: A hash containing contextual information about where the error occurred + +The server_context hash includes: + +- For tool calls: `{ tool_name: "name", arguments: { ... } }` +- For general request handling: `{ request: { ... } }` + +When an exception occurs: + +1. The exception is reported via the configured reporter +2. For tool calls, a generic error response is returned to the client: `{ error: "Internal error occurred", isError: true }` +3. For other requests, the exception is re-raised after reporting + +If no exception reporter is configured, a default no-op reporter is used that silently ignores exceptions. + +### Tools + +MCP spec includes [Tools](https://modelcontextprotocol.io/specification/latest/server/tools) which provide functionality to LLM apps. + +This gem provides a `MCP::Tool` class that can be used to create tools in three ways: + +1. As a class definition: + +```ruby +class MyTool < MCP::Tool + title "My Tool" + description "This tool performs specific functionality..." + input_schema( + properties: { + message: { type: "string" }, + }, + required: ["message"] + ) + output_schema( + properties: { + result: { type: "string" }, + success: { type: "boolean" }, + timestamp: { type: "string", format: "date-time" } + }, + required: ["result", "success", "timestamp"] + ) + annotations( + read_only_hint: true, + destructive_hint: false, + idempotent_hint: true, + open_world_hint: false, + title: "My Tool" + ) + + def self.call(message:, server_context:) + MCP::Tool::Response.new([{ type: "text", text: "OK" }]) + end end -# Call a specific tool. +tool = MyTool +``` + +2. By using the `MCP::Tool.define` method with a block: + +```ruby +tool = MCP::Tool.define( + name: "my_tool", + title: "My Tool", + description: "This tool performs specific functionality...", + annotations: { + read_only_hint: true, + title: "My Tool" + } +) do |args, server_context:| + MCP::Tool::Response.new([{ type: "text", text: "OK" }]) +end +``` + +3. By using the `MCP::Server#define_tool` method with a block: + +```ruby +server = MCP::Server.new +server.define_tool( + name: "my_tool", + description: "This tool performs specific functionality...", + annotations: { + title: "My Tool", + read_only_hint: true + } +) do |args, server_context:| + Tool::Response.new([{ type: "text", text: "OK" }]) +end +``` + +The server_context parameter is the server_context passed into the server and can be used to pass per request information, +e.g. around authentication state. + +### Tool Annotations + +Tools can include annotations that provide additional metadata about their behavior. The following annotations are supported: + +- `destructive_hint`: Indicates if the tool performs destructive operations. Defaults to true +- `idempotent_hint`: Indicates if the tool's operations are idempotent. Defaults to false +- `open_world_hint`: Indicates if the tool operates in an open world context. Defaults to true +- `read_only_hint`: Indicates if the tool only reads data (doesn't modify state). Defaults to false +- `title`: A human-readable title for the tool + +Annotations can be set either through the class definition using the `annotations` class method or when defining a tool using the `define` method. + +> [!NOTE] +> This **Tool Annotations** feature is supported starting from `protocol_version: '2025-03-26'`. + +### Tool Output Schemas + +Tools can optionally define an `output_schema` to specify the expected structure of their results. This works similarly to how `input_schema` is defined and can be used in three ways: + +1. **Class definition with output_schema:** + +```ruby +class WeatherTool < MCP::Tool + tool_name "get_weather" + description "Get current weather for a location" + + input_schema( + properties: { + location: { type: "string" }, + units: { type: "string", enum: ["celsius", "fahrenheit"] } + }, + required: ["location"] + ) + + output_schema( + properties: { + temperature: { type: "number" }, + condition: { type: "string" }, + humidity: { type: "integer" } + }, + required: ["temperature", "condition", "humidity"] + ) + + def self.call(location:, units: "celsius", server_context:) + # Call weather API and structure the response + api_response = WeatherAPI.fetch(location, units) + weather_data = { + temperature: api_response.temp, + condition: api_response.description, + humidity: api_response.humidity_percent + } + + output_schema.validate_result(weather_data) + + MCP::Tool::Response.new([{ + type: "text", + text: weather_data.to_json + }]) + end +end +``` + +2. **Using Tool.define with output_schema:** + +```ruby +tool = MCP::Tool.define( + name: "calculate_stats", + description: "Calculate statistics for a dataset", + input_schema: { + properties: { + numbers: { type: "array", items: { type: "number" } } + }, + required: ["numbers"] + }, + output_schema: { + properties: { + mean: { type: "number" }, + median: { type: "number" }, + count: { type: "integer" } + }, + required: ["mean", "median", "count"] + } +) do |args, server_context:| + # Calculate statistics and validate against schema + MCP::Tool::Response.new([{ type: "text", text: "Statistics calculated" }]) +end +``` + +3. **Using OutputSchema objects:** + +```ruby +class DataTool < MCP::Tool + output_schema MCP::Tool::OutputSchema.new( + properties: { + success: { type: "boolean" }, + data: { type: "object" } + }, + required: ["success"] + ) +end +``` + +Output schema may also describe an array of objects: + +```ruby +class WeatherTool < MCP::Tool + output_schema( + type: "array", + items: { + properties: { + temperature: { type: "number" }, + condition: { type: "string" }, + humidity: { type: "integer" } + }, + required: ["temperature", "condition", "humidity"] + } + ) +end +``` + +Please note: in this case, you must provide `type: "array"`. The default type +for output schemas is `object`. + +MCP spec for the [Output Schema](https://modelcontextprotocol.io/specification/latest/server/tools#output-schema) specifies that: + +- **Server Validation**: Servers MUST provide structured results that conform to the output schema +- **Client Validation**: Clients SHOULD validate structured results against the output schema +- **Better Integration**: Enables strict schema validation, type information, and improved developer experience +- **Backward Compatibility**: Tools returning structured content SHOULD also include serialized JSON in a TextContent block + +The output schema follows standard JSON Schema format and helps ensure consistent data exchange between MCP servers and clients. + +### Tool Responses with Structured Content + +Tools can return structured data alongside text content using the `structured_content` parameter. + +The structured content will be included in the JSON-RPC response as the `structuredContent` field. + +```ruby +class WeatherTool < MCP::Tool + description "Get current weather and return structured data" + + def self.call(location:, units: "celsius", server_context:) + # Call weather API and structure the response + api_response = WeatherAPI.fetch(location, units) + weather_data = { + temperature: api_response.temp, + condition: api_response.description, + humidity: api_response.humidity_percent + } + + output_schema.validate_result(weather_data) + + MCP::Tool::Response.new( + [{ + type: "text", + text: weather_data.to_json + }], + structured_content: weather_data + ) + end +end +``` + +### Tool Responses with Errors + +Tools can return error information alongside text content using the `error` parameter. + +The error will be included in the JSON-RPC response as the `isError` field. + +```ruby +class WeatherTool < MCP::Tool + description "Get current weather and return structured data" + + def self.call(server_context:) + # Do something here + content = {} + + MCP::Tool::Response.new( + [{ + type: "text", + text: content.to_json + }], + structured_content: content, + error: true + ) + end +end +``` + +### Prompts + +MCP spec includes [Prompts](https://modelcontextprotocol.io/specification/latest/server/prompts), which enable servers to define reusable prompt templates and workflows that clients can easily surface to users and LLMs. + +The `MCP::Prompt` class provides three ways to create prompts: + +1. As a class definition with metadata: + +```ruby +class MyPrompt < MCP::Prompt + prompt_name "my_prompt" # Optional - defaults to underscored class name + title "My Prompt" + description "This prompt performs specific functionality..." + arguments [ + MCP::Prompt::Argument.new( + name: "message", + title: "Message Title", + description: "Input message", + required: true + ) + ] + meta({ version: "1.0", category: "example" }) + + class << self + def template(args, server_context:) + MCP::Prompt::Result.new( + description: "Response description", + messages: [ + MCP::Prompt::Message.new( + role: "user", + content: MCP::Content::Text.new("User message") + ), + MCP::Prompt::Message.new( + role: "assistant", + content: MCP::Content::Text.new(args["message"]) + ) + ] + ) + end + end +end + +prompt = MyPrompt +``` + +2. Using the `MCP::Prompt.define` method: + +```ruby +prompt = MCP::Prompt.define( + name: "my_prompt", + title: "My Prompt", + description: "This prompt performs specific functionality...", + arguments: [ + MCP::Prompt::Argument.new( + name: "message", + title: "Message Title", + description: "Input message", + required: true + ) + ], + meta: { version: "1.0", category: "example" } +) do |args, server_context:| + MCP::Prompt::Result.new( + description: "Response description", + messages: [ + MCP::Prompt::Message.new( + role: "user", + content: MCP::Content::Text.new("User message") + ), + MCP::Prompt::Message.new( + role: "assistant", + content: MCP::Content::Text.new(args["message"]) + ) + ] + ) +end +``` + +3. Using the `MCP::Server#define_prompt` method: + +```ruby +server = MCP::Server.new +server.define_prompt( + name: "my_prompt", + description: "This prompt performs specific functionality...", + arguments: [ + Prompt::Argument.new( + name: "message", + title: "Message Title", + description: "Input message", + required: true + ) + ], + meta: { version: "1.0", category: "example" } +) do |args, server_context:| + Prompt::Result.new( + description: "Response description", + messages: [ + Prompt::Message.new( + role: "user", + content: Content::Text.new("User message") + ), + Prompt::Message.new( + role: "assistant", + content: Content::Text.new(args["message"]) + ) + ] + ) +end +``` + +The server_context parameter is the server_context passed into the server and can be used to pass per request information, +e.g. around authentication state or user preferences. + +### Key Components + +- `MCP::Prompt::Argument` - Defines input parameters for the prompt template with name, title, description, and required flag +- `MCP::Prompt::Message` - Represents a message in the conversation with a role and content +- `MCP::Prompt::Result` - The output of a prompt template containing description and messages +- `MCP::Content::Text` - Text content for messages + +### Usage + +Register prompts with the MCP server: + +```ruby +server = MCP::Server.new( + name: "my_server", + prompts: [MyPrompt], + server_context: { user_id: current_user.id }, +) +``` + +The server will handle prompt listing and execution through the MCP protocol methods: + +- `prompts/list` - Lists all registered prompts and their schemas +- `prompts/get` - Retrieves and executes a specific prompt with arguments + +### Instrumentation + +The server allows registering a callback to receive information about instrumentation. +To register a handler pass a proc/lambda to as `instrumentation_callback` into the server constructor. + +```ruby +MCP.configure do |config| + config.instrumentation_callback = ->(data) { + puts "Got instrumentation data #{data.inspect}" + } +end +``` + +The data contains the following keys: + +- `method`: the method called, e.g. `ping`, `tools/list`, `tools/call` etc +- `tool_name`: the name of the tool called +- `prompt_name`: the name of the prompt called +- `resource_uri`: the uri of the resource called +- `error`: if looking up tools/prompts etc failed, e.g. `tool_not_found` +- `duration`: the duration of the call in seconds + +`tool_name`, `prompt_name` and `resource_uri` are only populated if a matching handler is registered. +This is to avoid potential issues with metric cardinality + +### Resources + +MCP spec includes [Resources](https://modelcontextprotocol.io/specification/latest/server/resources). + +### Reading Resources + +The `MCP::Resource` class provides a way to register resources with the server. + +```ruby +resource = MCP::Resource.new( + uri: "https://example.com/my_resource", + name: "my-resource", + title: "My Resource", + description: "Lorem ipsum dolor sit amet", + mime_type: "text/html", +) + +server = MCP::Server.new( + name: "my_server", + resources: [resource], +) +``` + +The server must register a handler for the `resources/read` method to retrieve a resource dynamically. + +```ruby +server.resources_read_handler do |params| + [{ + uri: params[:uri], + mimeType: "text/plain", + text: "Hello from example resource! URI: #{params[:uri]}" + }] +end +``` + +otherwise `resources/read` requests will be a no-op. + +### Resource Templates + +The `MCP::ResourceTemplate` class provides a way to register resource templates with the server. + +```ruby +resource_template = MCP::ResourceTemplate.new( + uri_template: "https://example.com/my_resource_template", + name: "my-resource-template", + title: "My Resource Template", + description: "Lorem ipsum dolor sit amet", + mime_type: "text/html", +) + +server = MCP::Server.new( + name: "my_server", + resource_templates: [resource_template], +) +``` + +## Building an MCP Client + +The `MCP::Client` class provides an interface for interacting with MCP servers. + +This class supports: + +- Tool listing via the `tools/list` method (`MCP::Client#tools`) +- Tool invocation via the `tools/call` method (`MCP::Client#call_tools`) +- Resource listing via the `resources/list` method (`MCP::Client#resources`) +- Resource reading via the `resources/read` method (`MCP::Client#read_resources`) +- Prompt listing via the `prompts/list` method (`MCP::Client#prompts`) +- Prompt retrieval via the `prompts/get` method (`MCP::Client#get_prompt`) +- Automatic JSON-RPC 2.0 message formatting +- UUID request ID generation + +Clients are initialized with a transport layer instance that handles the low-level communication mechanics. +Authorization is handled by the transport layer. + +## Transport Layer Interface + +If the transport layer you need is not included in the gem, you can build and pass your own instances so long as they conform to the following interface: + +```ruby +class CustomTransport + # Sends a JSON-RPC request to the server and returns the raw response. + # + # @param request [Hash] A complete JSON-RPC request object. + # https://www.jsonrpc.org/specification#request_object + # @return [Hash] A hash modeling a JSON-RPC response object. + # https://www.jsonrpc.org/specification#response_object + def send_request(request:) + # Your transport-specific logic here + # - HTTP: POST to endpoint with JSON body + # - WebSocket: Send message over WebSocket + # - stdio: Write to stdout, read from stdin + # - etc. + end +end +``` + +### HTTP Transport Layer + +Use the `MCP::Client::HTTP` transport to interact with MCP servers using simple HTTP requests. + +You'll need to add `faraday` as a dependency in order to use the HTTP transport layer: + +```ruby +gem 'mcp' +gem 'faraday', '>= 2.0' +``` + +Example usage: + +```ruby +http_transport = MCP::Client::HTTP.new(url: "https://api.example.com/mcp") +client = MCP::Client.new(transport: http_transport) + +# List available tools +tools = client.tools +tools.each do |tool| + puts <<~TOOL_INFORMATION + Tool: #{tool.name} + Description: #{tool.description} + Input Schema: #{tool.input_schema} + TOOL_INFORMATION +end + +# Call a specific tool response = client.call_tool( tool: tools.first, arguments: { message: "Hello, world!" } ) - -# Close the transport when done. -stdio_transport.close ``` -The same client can connect to Streamable HTTP servers with `MCP::Client::HTTP`; -see [Client Transports](https://ruby.sdk.modelcontextprotocol.io/client/transports/). +#### HTTP Authorization -## Examples +By default, the HTTP transport layer provides no authentication to the server, but you can provide custom headers if you need authentication. For example, to use Bearer token authentication: -Runnable examples are available in [`examples/`](https://github.com/modelcontextprotocol/ruby-sdk/tree/main/examples), -including a complete Rails application in [`examples/rails`](https://github.com/modelcontextprotocol/ruby-sdk/tree/main/examples/rails). +```ruby +http_transport = MCP::Client::HTTP.new( + url: "https://api.example.com/mcp", + headers: { + "Authorization" => "Bearer my_token" + } +) + +client = MCP::Client.new(transport: http_transport) +client.tools # will make the call using Bearer auth +``` + +You can add any custom headers needed for your authentication scheme, or for any other purpose. The client will include these headers on every request. + +### Tool Objects + +The client provides a wrapper class for tools returned by the server: + +- `MCP::Client::Tool` - Represents a single tool with its metadata + +This class provides easy access to tool properties like name, description, input schema, and output schema. ## Documentation -- [SDK guides](https://ruby.sdk.modelcontextprotocol.io) - [SDK API documentation](https://rubydoc.info/gems/mcp) - [Model Context Protocol documentation](https://modelcontextprotocol.io) - -## License - -This project is licensed under the Apache License 2.0 for new contributions, with existing code under MIT. See the [LICENSE](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/LICENSE) file for details. diff --git a/ROADMAP.md b/ROADMAP.md deleted file mode 100644 index aa58422..0000000 --- a/ROADMAP.md +++ /dev/null @@ -1,51 +0,0 @@ -# Roadmap - -This roadmap outlines the MCP Ruby SDK's path toward SEP-1730 Tier 1. -It is a living document and will evolve as the SDK matures. - -## Current Status - -The SDK implements the 2025-06-18, 2025-11-25, and 2026-07-28 spec revisions, and passes all scored server -and client conformance scenarios for each revision's requirement set. -Optional protocol extensions (such as DPoP, workload identity federation, and the tasks extension) -are not yet implemented; SEP-1730 does not require extensions for any tier. - -## API Stability - -The 1.0.0 release marked the public API as stable: breaking changes ship only in major releases, -apart from the narrow exceptions documented in [VERSIONING.md](VERSIONING.md), -which also defines the Semantic Versioning scheme and breaking-change policy. - -## Deprecated Features - -The 2026-07-28 spec revision deprecates Roots, Sampling, and Logging (SEP-2577). -These features remain supported throughout 1.x: on the legacy lifecycle they work unchanged -(the deprecations do not apply there), and the 2026-07-28 lifecycle carries them through its own mechanisms: -roots-shaped and sampling-shaped input requests embedded in `InputRequiredResult` responses -(the SEP-2322 multi round-trip requests pattern) and per-request log delivery through the envelope's `logLevel`. -The replacements SEP-2577 names live outside the protocol: tool parameters or configuration for roots, -direct LLM provider APIs for sampling, and stderr or OpenTelemetry for logging. -The client emits a deprecation warning when a modern connect declares the deprecated Roots or Sampling capabilities. -Under Semantic Versioning their removal requires a major release, but no removal is scheduled yet: whether 2.0.0 removes -them depends on how future MCP spec revisions treat these features and on adoption of their replacements. - -## Conformance - -The SDK maintains a 100% conformance pass rate as new scenarios are added to the conformance suite. -Legacy SSE transport (2024-11-05) is intentionally out of scope; the SDK provides modern Streamable HTTP only. - -## Documentation - -Reference documentation covers all non-experimental features with examples. - -## Tracking New Spec Revisions - -The SDK aims to support each new MCP specification revision, with the implementation timeline agreed per -release based on feature complexity. -The 2026-07-28 revision shipped during 1.x: the server serves both lifecycle eras side by side, -so the SEP-2575 stateless lifecycle (including `server/discover` and `subscriptions/listen`), -SEP-2322 multi round-trip requests, SEP-2549 cache hints, and SEP-2243 custom headers are available alongside -the legacy handshake. The few incompatible adjustments the revision required shipped in -a minor release under the spec-conformance and security exceptions described in [VERSIONING.md](VERSIONING.md). -Removing legacy-era support is reserved for a future major release. -The tasks extension (SEP-2663) remains planned ([#391](https://github.com/modelcontextprotocol/ruby-sdk/issues/391)). diff --git a/Rakefile b/Rakefile index 409eef9..0d0ad08 100644 --- a/Rakefile +++ b/Rakefile @@ -14,90 +14,4 @@ require "rubocop/rake_task" RuboCop::RakeTask.new -task default: [:rubocop, :test, "conformance:test"] - -namespace :conformance do - desc "Run MCP conformance tests (PORT, SCENARIO, SPEC_VERSION, VERBOSE)" - task :test do |t| - next unless npx_available?(t.name) - - require_relative "conformance/server_runner" - require_relative "conformance/client_runner" - - options = {} - options[:port] = Integer(ENV["PORT"]) if ENV["PORT"] - options[:scenario] = ENV["SCENARIO"] if ENV["SCENARIO"] - options[:spec_version] = ENV["SPEC_VERSION"] if ENV["SPEC_VERSION"] - options[:verbose] = true if ENV["VERBOSE"] - - Conformance::ServerRunner.new(**options).run - Conformance::ClientRunner.new(**options.reject { |key, _value| key == :port }).run - end - - desc "List available conformance scenarios" - task :list do |t| - next unless npx_available?(t.name) - - system("npx", "--yes", "@modelcontextprotocol/conformance", "list", "--server") - system("npx", "--yes", "@modelcontextprotocol/conformance", "list", "--client") - end - - desc "Start the conformance server (PORT)" - task :server do - require_relative "conformance/server" - - options = {} - options[:port] = Integer(ENV["PORT"]) if ENV["PORT"] - - Conformance::Server.new(**options).start - end -end - -# The other two former names now fail with a "Did you mean?" suggestion, but a bare `conformance` -# would match the `conformance/` directory: Rake synthesizes a file task for it and exits 0 without -# running anything. This keeps the name pointing at the suite instead of at that silent no-op. -desc "Alias for conformance:test" -task conformance: "conformance:test" - -namespace :docs do - desc "Serve the documentation site locally at http://localhost:4000 (PORT)" - task :preview do - docs_dir = File.expand_path("docs", __dir__) - generate_docs_versions_data(docs_dir) - - env = { - "BUNDLE_GEMFILE" => File.join(docs_dir, "Gemfile"), - "RUBYOPT" => "-r#{File.join(docs_dir, "_preview", "taint_shim.rb")}", - } - port = ENV.fetch("PORT", "4000") - - Bundler.with_unbundled_env do - system(env, "bundle", "install", "--quiet", chdir: docs_dir, exception: true) - system(env, "bundle", "exec", "jekyll", "serve", "--port", port, chdir: docs_dir, exception: true) - rescue Interrupt - # Ctrl-C is the way to stop the preview, not an error. - end - end -end - -# Mirrors bin/generate-gh-pages.sh: the released site receives `_data/versions.yml` from -# the version tags at deploy time, and the preview generates the same data so the nav footer -# shows the released-gem version line. -def generate_docs_versions_data(docs_dir) - versions = %x(git tag --list).split("\n").filter_map { |tag| - tag[/\A[^0-9]*(\d+\.\d+\.\d+(?:-[a-zA-Z0-9.-]+)?)\z/, 1] - }.sort_by { |version| - Gem::Version.new(version) - }.reverse - return if versions.empty? - - mkdir_p(File.join(docs_dir, "_data")) - File.write(File.join(docs_dir, "_data", "versions.yml"), versions.map { |version| "- #{version}\n" }.join) -end - -def npx_available?(task_name) - return true if system("which", "npx", out: File::NULL, err: File::NULL) - - warn("Skipping #{task_name}: npx is not installed. Install Node.js to run this task: https://nodejs.org/") - false -end +task default: [:test, :rubocop] diff --git a/SECURITY.md b/SECURITY.md deleted file mode 100644 index 5029242..0000000 --- a/SECURITY.md +++ /dev/null @@ -1,21 +0,0 @@ -# Security Policy - -Thank you for helping keep the Model Context Protocol and its ecosystem secure. - -## Reporting Security Issues - -If you discover a security vulnerability in this repository, please report it through -the [GitHub Security Advisory process](https://docs.github.com/en/code-security/security-advisories/guidance-on-reporting-and-writing-information-about-vulnerabilities/privately-reporting-a-security-vulnerability) -for this repository. - -Please **do not** report security vulnerabilities through public GitHub issues, discussions, -or pull requests. - -## What to Include - -To help us triage and respond quickly, please include: - -- A description of the vulnerability -- Steps to reproduce the issue -- The potential impact -- Any suggested fixes (optional) diff --git a/VERSIONING.md b/VERSIONING.md deleted file mode 100644 index 1b2cd88..0000000 --- a/VERSIONING.md +++ /dev/null @@ -1,56 +0,0 @@ -# Versioning Policy - -The MCP Ruby SDK follows [Semantic Versioning 2.0.0](https://semver.org/spec/v2.0.0.html). -This document describes what each version component means for users of the `mcp` gem, -what counts as a breaking change, and how breaking changes are communicated. - -## Version Scheme - -Given a version number `MAJOR.MINOR.PATCH`: - -- **MAJOR** is incremented for incompatible changes to the public API. -- **MINOR** is incremented for backwards-compatible new functionality. -- **PATCH** is incremented for backwards-compatible bug fixes. - -### Current 0.x Phase - -While the SDK is at version 0.x, the public API is not yet considered stable. -Following SemVer conventions for initial development, minor releases (0.x -> 0.y) may contain breaking changes. -All breaking changes are recorded in [CHANGELOG.md](CHANGELOG.md). - -### After 1.0.0 - -Once 1.0.0 is released, breaking changes will only ship in major releases, with the exceptions described below. - -## What Counts as a Breaking Change - -A breaking change is any change that requires users to modify their code when upgrading, including: - -- Removing or renaming a public class, module, method, or constant -- Changing a public method's signature in a way that rejects previously valid arguments -- Changing documented behavior that users can reasonably depend on - -New functionality that is purely additive (new classes, new methods, new optional keyword arguments) -is not a breaking change. - -## Exceptions: Spec Compliance, Security, and Clear Defects - -Minor releases avoid incompatible changes as much as possible. However, the SDK's primary contract is -conformance to the [MCP specification](https://modelcontextprotocol.io/specification/). -Behavior that deviates from the specification is treated as a bug, even when users may have come to rely on it. -Therefore, incompatible changes may be shipped in a minor release when they are required to: - -- Fix incorrect conformance to the MCP specification -- Address a security vulnerability -- Fix a clear defect, such as behavior that contradicts the documentation, a crash, - or data corruption, where compatibility would mean preserving the defect - -When such a change ships, the release notes and CHANGELOG entry explicitly call out the incompatibility -and describe how to migrate. - -## How Breaking Changes Are Communicated - -- [CHANGELOG.md](CHANGELOG.md) records every release in [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) format; - breaking changes appear under the "Changed" or "Removed" headings -- [GitHub Releases](https://github.com/modelcontextprotocol/ruby-sdk/releases) mirror the changelog for each release -- Where practical, deprecation warnings are added at least one minor release before removal diff --git a/conformance/README.md b/conformance/README.md deleted file mode 100644 index 1e2e660..0000000 --- a/conformance/README.md +++ /dev/null @@ -1,105 +0,0 @@ -# MCP Conformance Tests - -Validates the Ruby SDK's conformance to the MCP specification using [`@modelcontextprotocol/conformance`](https://github.com/modelcontextprotocol/conformance). - -## Prerequisites - -- Node.js (for `npx`) -- `bundle install` completed - -## Running the Tests - -### Run all scenarios - -```bash -bundle exec rake conformance:test -``` - -Runs both server and client conformance tests in sequence. Server conformance starts the -conformance server and tests it. Client conformance spawns test servers for each scenario -and invokes `conformance/client.rb` against them. Scenarios listed in `expected_failures.yml` -are allowed to fail without affecting the exit code. - -### Environment variables - -| Variable | Description | Default | -|----------------|---------------------------------------|---------| -| `PORT` | Server port (server conformance only) | `9292` | -| `SCENARIO` | Run a single scenario by name | (all) | -| `SPEC_VERSION` | Filter scenarios by spec version | (all) | -| `VERBOSE` | Show raw JSON output when set | (off) | - -```bash -# Run a single server scenario -bundle exec rake conformance:test SCENARIO=ping - -# Use a different port with verbose output -bundle exec rake conformance:test PORT=3000 VERBOSE=1 - -# Start the server on a specific port -bundle exec rake conformance:server PORT=3000 -``` - -### Start the server and test separately - -```bash -# Terminal 1: start the server -bundle exec rake conformance:server - -# Terminal 2: run all scenarios -npx @modelcontextprotocol/conformance@alpha server --url http://localhost:9292/mcp - -# Terminal 2: run a single scenario -npx @modelcontextprotocol/conformance@alpha server --url http://localhost:9292/mcp --scenario ping -``` - -Keeps the server alive between test runs, which avoids the startup overhead when iterating -on a single scenario. Stop the server with Ctrl+C when done. - -### List available scenarios - -```bash -bundle exec rake conformance:list -``` - -Prints all scenario names that can be passed to `SCENARIO`. - -## SDK Tier Report - -The [MCP SDK Tier system](https://modelcontextprotocol.io/community/sdk-tiers) requires SDK -maintainers to self-assess and report results to the SDK Working Group via -[modelcontextprotocol/modelcontextprotocol issues](https://github.com/modelcontextprotocol/modelcontextprotocol/issues). - -To generate a full tier assessment report, use the `/mcp-sdk-tier-audit` slash command from -the [modelcontextprotocol/conformance](https://github.com/modelcontextprotocol/conformance) -repository with the conformance server running: - -```bash -# Terminal 1 (this repository): start the conformance server -bundle exec rake conformance:server - -# Terminal 2 (conformance repository): run the tier audit skill as a slash command in Claude Code -/mcp-sdk-tier-audit /path/to/modelcontextprotocol/ruby-sdk http://localhost:9292/mcp -``` - -The skill evaluates conformance pass rate, issue label taxonomy, triage metrics, documentation -coverage, and policy compliance, then produces a markdown report suitable for tier advancement -submissions. - -## File Structure - -``` -conformance/ - server.rb # Conformance server (Rack + Puma, default port 9292) - server_runner.rb # Starts the server, runs npx conformance server, exits with result code - client.rb # Conformance client (invoked by npx conformance client) - client_runner.rb # Runs npx conformance client, exits with result code - expected_failures.yml # Baseline of known-failing scenarios (server and client) - README.md # This file -``` - -## Known Limitations - -Known-failing scenarios are registered in `conformance/expected_failures.yml`. They are allowed to -fail without affecting the exit code and are tracked to catch regressions. -These are shown in the output of `bundle exec rake conformance:test`. diff --git a/conformance/client.rb b/conformance/client.rb deleted file mode 100644 index b568e2e..0000000 --- a/conformance/client.rb +++ /dev/null @@ -1,306 +0,0 @@ -# frozen_string_literal: true - -# Conformance test client for the MCP Ruby SDK. -# Invoked by the conformance runner: -# MCP_CONFORMANCE_SCENARIO= bundle exec ruby conformance/client.rb -# -# The server URL is passed as the last positional argument. -# The scenario name is read from the MCP_CONFORMANCE_SCENARIO environment variable, -# which is set automatically by the conformance test runner. - -require "faraday" -require "json" -require_relative "../lib/mcp" - -scenario = ENV["MCP_CONFORMANCE_SCENARIO"] -server_url = ARGV.last - -unless scenario && server_url - abort("Usage: MCP_CONFORMANCE_SCENARIO= ruby conformance/client.rb ") -end - -# URL the conformance harness expects to see as the OAuth `client_id` for the `auth/basic-cimd` scenario -# when the AS advertises `client_id_metadata_document_supported`. The harness does not fetch the document, -# only matches the value, so the URL does not need to resolve. -CONFORMANCE_CIMD_URL = "https://conformance-test.local/client-metadata.json" - -# The conformance harness optionally injects scenario-specific data via -# the `MCP_CONFORMANCE_CONTEXT` environment variable as a JSON document. The shape is -# defined by the harness, not the MCP spec, and has varied between versions: -# -# - Newer (`@modelcontextprotocol/conformance` >= 0.x): scenario fields are -# spread at the top level alongside `name`, e.g. -# `{"name":"auth/pre-registration","client_id":"...","client_secret":"..."}`. -# - Older: a nested `context` object: `{"name":"...","context":{...}}`. -# -# Both shapes are accepted so the client conforms to whichever harness version -# the developer has on hand. -def conformance_context - raw = ENV["MCP_CONFORMANCE_CONTEXT"] - return {} if raw.nil? || raw.empty? - - parsed = JSON.parse(raw) - return {} unless parsed.is_a?(Hash) - - if parsed["context"].is_a?(Hash) - parsed["context"] - else - parsed.reject { |key, _| key == "name" } - end -rescue JSON::ParserError - {} -end - -# Saves the pre-registered `client_id` / `client_secret` the harness injects -# via context (used by pre-registration and client_credentials scenarios). -def storage_for(context) - storage = MCP::Client::OAuth::InMemoryStorage.new - if context["client_id"] - storage.save_client_information( - "client_id" => context["client_id"], - "client_secret" => context["client_secret"], - "token_endpoint_auth_method" => context["token_endpoint_auth_method"] || "client_secret_basic", - ) - end - storage -end - -# Builds a `client_credentials`-only provider (machine-to-machine, no redirect). -# The pre-registered credentials are injected by the harness via context: -# a shared secret for the basic scenario, or a PEM private key plus signing algorithm -# (default ES256, matching the TypeScript and Python conformance clients) -# for the `private_key_jwt` scenario. -def build_client_credentials_provider(context) - if context["private_key_pem"] - MCP::Client::OAuth::ClientCredentialsProvider.new( - client_id: context["client_id"], - token_endpoint_auth_method: "private_key_jwt", - private_key: context["private_key_pem"], - signing_algorithm: context["signing_algorithm"] || "ES256", - ) - else - MCP::Client::OAuth::ClientCredentialsProvider.new( - client_id: context["client_id"], - client_secret: context["client_secret"], - token_endpoint_auth_method: context["token_endpoint_auth_method"] || "client_secret_basic", - ) - end -end - -# Builds a SEP-990 Cross-App Access provider: the harness injects an IdP ID token plus the IdP token endpoint -# via context; the assertion provider exchanges them for an ID-JAG (RFC 8693), which the flow then presents to -# the MCP authorization server with the jwt-bearer grant. -def build_cross_app_access_provider(context) - assertion_provider = ->(audience:, resource:) do - MCP::Client::OAuth::IDJAGTokenExchange.request( - token_endpoint: context["idp_token_endpoint"], - id_token: context["idp_id_token"], - client_id: context["idp_client_id"], - audience: audience, - resource: resource, - ) - end - - MCP::Client::OAuth::CrossAppAccessProvider.new( - client_id: context["client_id"], - client_secret: context["client_secret"], - assertion_provider: assertion_provider, - ) -end - -# Builds an OAuth provider that drives the authorization code + PKCE + DCR flow -# non-interactively against the conformance test's auth server. The conformance -# `/authorize` endpoint redirects synchronously to `redirect_uri` with -# `code=test-auth-code`, so we follow it manually instead of opening a browser. -def build_oauth_provider(context, scenario:) - callback_holder = {} - redirect_uri = "http://localhost:0/callback" - - redirect_handler = ->(authorization_url) do - response = Faraday.new.get(authorization_url) do |req| - req.options.params_encoder = nil - end - location = response.headers["location"] || response.headers["Location"] - abort("Authorization request did not redirect: #{response.status}.") unless location - - callback_holder[:url] = URI.parse(location) - end - - callback_handler = -> do - query = URI.decode_www_form(callback_holder.fetch(:url).query).to_h - # The 3-element form opts into SEP-2468 / RFC 9207 `iss` validation; - # `query["iss"]` is nil when the authorization response carried no `iss`. - [query["code"], query["state"], query["iss"]] - end - - MCP::Client::OAuth::Provider.new( - client_metadata: { - client_name: "ruby-sdk-conformance-client", - redirect_uris: [redirect_uri], - grant_types: ["authorization_code", "refresh_token"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: redirect_uri, - redirect_handler: redirect_handler, - callback_handler: callback_handler, - storage: storage_for(context), - client_id_metadata_document_url: (scenario == "auth/basic-cimd" ? CONFORMANCE_CIMD_URL : nil), - ) -end - -def build_provider_for(scenario, context) - if context["idp_id_token"] - build_cross_app_access_provider(context) - elsif scenario.start_with?("auth/client-credentials") - build_client_credentials_provider(context) - else - build_oauth_provider(context, scenario: scenario) - end -end - -oauth = scenario.start_with?("auth/") ? build_provider_for(scenario, conformance_context) : nil -transport = MCP::Client::HTTP.new(url: server_url, oauth: oauth) -client = MCP::Client.new(transport: transport) - -# SEP-2322: the MRTR scenario exercises the automatic driver; this elicitation handler accepts -# every embedded confirmation request, and the driver echoes `requestState` byte-exactly. -# The same registration answers a real `elicitation/create` request, so nothing here is MRTR-specific. -if scenario == "sep-2322-client-request-state" - client.on_elicitation { |_params| { action: "accept", content: { confirmed: true } } } -end -capabilities = scenario == "elicitation-sep1034-client-defaults" ? { elicitation: {} } : {} -# The conformance harness asserts on the observed protocol exchange, not on the client's exit status, -# and echoes the client's output only when the exit status is non-zero. Several negative auth scenarios -# (e.g. `auth/resource-mismatch`, `auth/scope-retry-limit`) are expected to drive the client into -# a terminal failure: the SDK correctly refuses a mismatched resource or stops after the scope step-up -# retry limit. Report such an expected failure as a one-line reason and exit cleanly so the run stays -# free of noise, while letting any unexpected error (a real SDK bug) still raise with a full backtrace -# and a failing exit status. -begin - # The harness names the wire version per scenario run: the 2026 draft selects the stateless modern lifecycle, - # and every dated version through 2025-11-25 keeps the legacy `initialize` handshake - # (pinned rather than `:auto`, whose `server/discover` probe the legacy scenario servers do not expect). - mode = ENV["MCP_CONFORMANCE_PROTOCOL_VERSION"] == "2026-07-28" ? :modern : :legacy - connect = lambda do - client.connect( - client_info: { name: "ruby-sdk-conformance-client", version: MCP::VERSION }, - capabilities: capabilities, - mode: mode, - ) - end - - begin - connect.call - rescue MCP::Client::RequestHandlerError - # SEP-2575 version negotiation: a server may reject the first request with `-32022` naming - # its supported versions. Retry once so the harness observes a follow-up request carrying - # a mutually supported version (this client already speaks the latest draft). - raise unless mode == :modern - - connect.call - end - - case scenario - when "initialize" - client.tools - when "json-schema-2020-12-preservation" - # SEP-1613/SEP-2106: echo the focal tool's observed inputSchema verbatim so the harness - # can diff what the client preserved. Preservation holds because `Client::Tool#input_schema` - # is the parsed response untouched. - tools = client.tools - focal = tools.find { |t| t.name == "json_schema_2020_12_tool" } - abort("Tool json_schema_2020_12_tool not found") unless focal - client.call_tool(name: "json_schema_echo", arguments: { "schema" => focal.input_schema }) - when "request-metadata" - # SEP-2575: the checks read the envelope and headers of the requests the modern connect - # and this listing already produce. - client.tools - when "sep-2322-client-request-state" - # SEP-2322: the driver resumes `test_mrtr_echo_state` automatically (fresh JSON-RPC id, - # byte-exact `requestState` echo); `test_mrtr_unrelated` must carry neither retry field; - # `test_mrtr_no_state` retries without inventing a state; `test_mrtr_no_result_type` - # has no `resultType` and therefore must be treated as complete, with no retry. - client.tools - client.call_tool(name: "test_mrtr_echo_state", arguments: {}) - client.call_tool(name: "test_mrtr_unrelated", arguments: {}) - client.call_tool(name: "test_mrtr_no_state", arguments: {}) - client.call_tool(name: "test_mrtr_no_result_type", arguments: {}) - when "http-custom-headers" - # SEP-2243: the harness names the exact tool calls (with encoding edge-case values) via context; - # listing first teaches the transport the `x-mcp-header` declarations it mirrors. - client.tools - (conformance_context["toolCalls"] || []).each do |tool_call| - client.call_tool(name: tool_call["name"], arguments: tool_call["arguments"]) - end - when "http-invalid-tool-headers" - # SEP-2243: the listing carries one valid tool among invalid `x-mcp-header` definitions; - # calling only the valid one shows the invalid definitions did not block it. - client.tools - client.call_tool(name: "valid_tool", arguments: { "message" => "hello" }) - when "http-standard-headers" - # SEP-2243: the harness inspects the `Mcp-Method` header on every POST and the `Mcp-Name` header on - # the name-carrying requests, so drive one of each standard request kind. - tools = client.tools - tool = tools.find { |t| t.name == "test_headers" } || tools.first - abort("No tool exposed by conformance server for #{scenario}") unless tool - client.call_tool(tool: tool, arguments: {}) - - resource = client.resources.first - abort("No resource exposed by conformance server for #{scenario}") unless resource - client.read_resource(uri: resource["uri"]) - - prompt = client.prompts.first - abort("No prompt exposed by conformance server for #{scenario}") unless prompt - client.get_prompt(name: prompt["name"]) - when "json-schema-ref-no-deref" - # SEP-2106: listing tools whose schemas carry `$ref` must not trigger network dereferencing. - client.tools - when "tools_call" - tools = client.tools - add_numbers = tools.find { |t| t.name == "add_numbers" } - abort("Tool add_numbers not found") unless add_numbers - client.call_tool(tool: add_numbers, arguments: { a: 1, b: 2 }) - when "sse-retry" - # SEP-1699: the server closes the tools/call SSE stream right after a priming event. - # The transport waits the server's `retry:` interval, reconnects with a GET carrying `Last-Event-ID`, - # and receives the tool result on the resumed stream; the harness verifies the reconnect, - # its timing, and the header. - tools = client.tools - test_reconnection = tools.find { |t| t.name == "test_reconnection" } - abort("Tool test_reconnection not found") unless test_reconnection - client.call_tool(tool: test_reconnection, arguments: {}) - when "elicitation-sep1034-client-defaults" - # SEP-1034: the server sends `elicitation/create` on the tools/call SSE stream with every property declaring - # a `default` and none required. The handler accepts and fills the omitted fields from those defaults. - client.on_elicitation do |params| - { action: "accept", content: MCP::Client::Elicitation.apply_defaults(params["requestedSchema"] || {}) } - end - - tools = client.tools - defaults_tool = tools.find { |t| t.name == "test_client_elicitation_defaults" } - - abort("Tool test_client_elicitation_defaults not found") unless defaults_tool - - client.call_tool(tool: defaults_tool, arguments: {}) - when %r|\Aauth/| - # Auth-only scenarios: the protocol-level checks (PRM/AS metadata, DCR, PKCE, token usage) - # are observed by the conformance server during `connect` and the subsequent request below. - # Listing tools forces a second authenticated MCP request so the bearer token usage check fires. - tools = client.tools - - # `auth/scope-step-up` only fires its escalation 403 on `tools/call`, not `tools/list`, - # so the client must actually invoke a tool to drive the second authorization request - # the scenario asserts on. - if scenario == "auth/scope-step-up" - tool = tools.find { |t| t.name == "test-tool" } || tools.first - abort("No tool exposed by conformance server for #{scenario}") unless tool - client.call_tool(tool: tool, arguments: {}) - end - else - abort("Unknown or unsupported scenario: #{scenario}") - end -rescue MCP::Client::OAuth::Flow::AuthorizationError, MCP::Client::RequestHandlerError, Faraday::Error => e - warn("#{scenario}: client ended in the expected terminal failure (#{e.class}: #{e.message})") - exit -end diff --git a/conformance/client_runner.rb b/conformance/client_runner.rb deleted file mode 100644 index 418e7f4..0000000 --- a/conformance/client_runner.rb +++ /dev/null @@ -1,48 +0,0 @@ -# frozen_string_literal: true - -# Runs `npx @modelcontextprotocol/conformance@alpha client` against the conformance client script. -require "English" - -module Conformance - class ClientRunner - def initialize(scenario: nil, spec_version: nil, verbose: false) - @scenario = scenario - @spec_version = spec_version - @verbose = verbose - end - - def run - command = build_command - puts "Command: #{command.join(" ")}\n\n" - - system(*command) - conformance_exit_code = $CHILD_STATUS.exitstatus - exit(conformance_exit_code || 1) unless conformance_exit_code == 0 - end - - private - - def build_command - expected_failures_yml = File.expand_path("expected_failures.yml", __dir__) - client_script = File.expand_path("client.rb", __dir__) - - npx_command = [ - "npx", - "--yes", - "@modelcontextprotocol/conformance@alpha", - "client", - "--command", - "bundle exec ruby #{client_script}", - ] - npx_command += if @scenario - ["--scenario", @scenario] - else - ["--suite", "all"] - end - npx_command += ["--spec-version", @spec_version] if @spec_version - npx_command += ["--verbose"] if @verbose - npx_command += ["--expected-failures", expected_failures_yml] - npx_command - end - end -end diff --git a/conformance/expected_failures.yml b/conformance/expected_failures.yml deleted file mode 100644 index 9325842..0000000 --- a/conformance/expected_failures.yml +++ /dev/null @@ -1,6 +0,0 @@ -server: [] -client: - # Unimplemented authorization extensions. - - auth/dpop - - auth/dpop-nonce - - auth/wif-jwt-bearer diff --git a/conformance/server.rb b/conformance/server.rb deleted file mode 100644 index a3f781d..0000000 --- a/conformance/server.rb +++ /dev/null @@ -1,1107 +0,0 @@ -# frozen_string_literal: true - -require "rackup" -require "json" -require "securerandom" -require "set" -require "uri" -require_relative "../lib/mcp" - -module Conformance - # 1x1 red PNG pixel (matches TypeScript SDK and Python SDK) - BASE64_1X1_PNG = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg==" - - # Minimal WAV file (matches TypeScript SDK and Python SDK) - BASE64_MINIMAL_WAV = "UklGRiYAAABXQVZFZm10IBAAAAABAAEAQB8AAAB9AAACABAAZGF0YQIAAAA=" - - # SEP-2322 MRTR fixture helpers. A retried request re-runs its handler from the start, - # so every round reads the client's earlier answers back through these. - module Mrtr - module_function - - # The transport parses JSON with symbolized keys, but retries may also arrive through - # `Server#handle` with string keys; tolerate both like the SDK's own readers. - def read(hash, key) - return unless hash.is_a?(Hash) - - value = hash[key.to_sym] - value.nil? ? hash[key.to_s] : value - end - - # The `content` of an accepted `elicitation/create` response, or `nil` for a declined, - # malformed, or missing one (a `nil` return re-requests the input). - def accepted_content(response) - content = read(response, :content) - content if read(response, :action) == "accept" && content.is_a?(Hash) - end - - # The `text` of a `sampling/createMessage` response, or `nil` when malformed. - def sampled_text(response) - text = read(read(response, :content), :text) - text if text.is_a?(String) - end - - def parse_state(request_state) - return unless request_state.is_a?(String) - - parsed = JSON.parse(request_state) - parsed.is_a?(Hash) ? parsed : nil - rescue JSON::ParserError - nil - end - end - - module Tools - class TestSimpleText < MCP::Tool - tool_name "test_simple_text" - description "A tool that returns simple text content" - - class << self - def call(**_args) - MCP::Tool::Response.new([MCP::Content::Text.new("This is a simple text response for testing.").to_h]) - end - end - end - - class TestImageContent < MCP::Tool - tool_name "test_image_content" - description "A tool that returns image content" - - class << self - def call(**_args) - MCP::Tool::Response.new([MCP::Content::Image.new(BASE64_1X1_PNG, "image/png").to_h]) - end - end - end - - class TestAudioContent < MCP::Tool - tool_name "test_audio_content" - description "A tool that returns audio content" - - class << self - def call(**_args) - MCP::Tool::Response.new([MCP::Content::Audio.new(BASE64_MINIMAL_WAV, "audio/wav").to_h]) - end - end - end - - class TestEmbeddedResource < MCP::Tool - tool_name "test_embedded_resource" - description "A tool that returns embedded resource content" - - class << self - def call(**_args) - text_contents = MCP::Resource::TextContents.new( - uri: "test://embedded-resource", - mime_type: "text/plain", - text: "This is an embedded resource content.", - ) - MCP::Tool::Response.new([MCP::Content::EmbeddedResource.new(text_contents).to_h]) - end - end - end - - class TestMultipleContentTypes < MCP::Tool - tool_name "test_multiple_content_types" - description "A tool that returns multiple content types" - - class << self - def call(**_args) - MCP::Tool::Response.new([ - MCP::Content::Text.new("Multiple content types test:").to_h, - MCP::Content::Image.new(BASE64_1X1_PNG, "image/png").to_h, - MCP::Content::EmbeddedResource.new( - MCP::Resource::TextContents.new( - uri: "test://mixed-content-resource", - mime_type: "application/json", - text: '{"test":"data","value":123}', - ), - ).to_h, - ]) - end - end - end - - class TestErrorHandling < MCP::Tool - tool_name "test_error_handling" - description "A tool that intentionally returns an error for testing" - - class << self - def call(**_args) - MCP::Tool::Response.new( - [MCP::Content::Text.new("This tool intentionally returns an error for testing").to_h], - error: true, - ) - end - end - end - - class JsonSchema202012Tool < MCP::Tool - tool_name "json_schema_2020_12_tool" - description "Tool with JSON Schema 2020-12 features" - input_schema( - "$schema": "https://json-schema.org/draft/2020-12/schema", - "$defs": { - address: { - type: "object", - properties: { - street: { type: "string" }, - city: { type: "string" }, - }, - }, - }, - properties: { - name: { type: "string" }, - address: { "$ref": "#/$defs/address" }, - }, - additionalProperties: false, - ) - - class << self - def call(**_args) - MCP::Tool::Response.new([MCP::Content::Text.new("Processed with JSON Schema 2020-12").to_h]) - end - end - end - - class TestToolWithLogging < MCP::Tool - tool_name "test_tool_with_logging" - description "A tool that sends log messages during execution" - - class << self - def call(server_context:, **_args) - server_context.notify_log_message(data: "Tool execution started", level: "info", logger: "test_logger") - sleep(0.05) # Required by the conformance test to verify clients handle interleaved notifications (same as TypeScript SDK). - server_context.notify_log_message(data: "Tool processing data", level: "info", logger: "test_logger") - sleep(0.05) # Same as above. - server_context.notify_log_message(data: "Tool execution completed", level: "info", logger: "test_logger") - MCP::Tool::Response.new([MCP::Content::Text.new("Logging complete (3 messages sent)").to_h]) - end - end - end - - class TestToolWithProgress < MCP::Tool - tool_name "test_tool_with_progress" - description "A tool that reports progress notifications" - - class << self - def call(server_context:, **_args) - server_context.report_progress(0, total: 100) - server_context.report_progress(50, total: 100) - server_context.report_progress(100, total: 100) - - MCP::Tool::Response.new([MCP::Content::Text.new("Progress complete").to_h]) - end - end - end - - class TestSampling < MCP::Tool - tool_name "test_sampling" - description "A tool that requests LLM sampling from the client" - input_schema( - properties: { prompt: { type: "string" } }, - required: ["prompt"], - ) - - class << self - def call(prompt:, server_context:) - result = server_context.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: prompt } }], - max_tokens: 100, - ) - model = result[:model] || "unknown" - text = result.dig(:content, :text) || "" - - MCP::Tool::Response.new([MCP::Content::Text.new("LLM response: #{text} (model: #{model})").to_h]) - end - end - end - - class TestElicitation < MCP::Tool - tool_name "test_elicitation" - description "A tool that requests user input from the client" - input_schema( - properties: { message: { type: "string" } }, - required: ["message"], - ) - - class << self - def call(server_context:, message:) - result = server_context.create_form_elicitation( - message: message, - requested_schema: { - type: "object", - properties: { - username: { type: "string", description: "User's response" }, - email: { type: "string", description: "User's email address" }, - }, - required: ["username", "email"], - }, - ) - MCP::Tool::Response.new([MCP::Content::Text.new("User response: #{result}").to_h]) - end - end - end - - class TestElicitationSep1034Defaults < MCP::Tool - tool_name "test_elicitation_sep1034_defaults" - description "A tool that tests elicitation with default values" - - class << self - def call(server_context:, **_args) - result = server_context.create_form_elicitation( - message: "Please provide your information (with defaults)", - requested_schema: { - type: "object", - properties: { - name: { type: "string", default: "John Doe" }, - age: { type: "integer", default: 30 }, - score: { type: "number", default: 95.5 }, - status: MCP::Elicitation::EnumSchema.untitled_single_select( - values: ["active", "inactive", "pending"], default: "active", - ).to_h, - verified: { type: "boolean", default: true }, - }, - }, - ) - MCP::Tool::Response.new([MCP::Content::Text.new("Elicitation result: #{result}").to_h]) - end - end - end - - class TestElicitationSep1330Enums < MCP::Tool - tool_name "test_elicitation_sep1330_enums" - description "A tool that tests elicitation with enum schemas" - - class << self - def call(server_context:, **_args) - # Built with the SEP-1330 builders so the conformance run exercises the same schemas - # the SDK produces for users. - result = server_context.create_form_elicitation( - message: "Please select options", - requested_schema: { - type: "object", - properties: { - untitledSingle: MCP::Elicitation::EnumSchema.untitled_single_select( - values: ["option1", "option2", "option3"], - ).to_h, - titledSingle: MCP::Elicitation::EnumSchema.titled_single_select( - options: [ - { value: "value1", title: "First Option" }, - { value: "value2", title: "Second Option" }, - { value: "value3", title: "Third Option" }, - ], - ).to_h, - legacyEnum: MCP::Elicitation::EnumSchema.legacy_titled( - values: ["opt1", "opt2", "opt3"], - value_titles: ["Option One", "Option Two", "Option Three"], - ).to_h, - untitledMulti: MCP::Elicitation::EnumSchema.untitled_multi_select( - values: ["option1", "option2", "option3"], - ).to_h, - titledMulti: MCP::Elicitation::EnumSchema.titled_multi_select( - options: [ - { value: "value1", title: "First Choice" }, - { value: "value2", title: "Second Choice" }, - { value: "value3", title: "Third Choice" }, - ], - ).to_h, - }, - }, - ) - MCP::Tool::Response.new([MCP::Content::Text.new("Elicitation result: #{result}").to_h]) - end - end - end - - class TestReconnection < MCP::Tool - tool_name "test_reconnection" - description "A tool that triggers SSE stream closure to test client reconnection behavior" - - class << self - def call(**_args) - MCP::Tool::Response.new([MCP::Content::Text.new("Reconnection test completed").to_h]) - end - end - end - - class TestMissingCapability < MCP::Tool - tool_name "test_missing_capability" - description "A tool that requires the sampling client capability (SEP-2575)" - - class << self - def call(server_context:, **_args) - server_context.require_client_capability!(:sampling) - - MCP::Tool::Response.new([MCP::Content::Text.new("Sampling capability is declared").to_h]) - end - end - end - - class TestStreamingElicitation < MCP::Tool - tool_name "test_streaming_elicitation" - description "A tool whose response stream carries only notifications, never independent requests (SEP-2575)" - - class << self - def call(server_context:, **_args) - # No independent server-to-client request is ever written to the response stream; - # the progress notification only goes out when the request carried a progressToken. - server_context.report_progress(50, total: 100) - - MCP::Tool::Response.new([MCP::Content::Text.new("Streaming complete").to_h]) - end - end - end - - class TestInputRequiredResultElicitation < MCP::Tool - tool_name "test_input_required_result_elicitation" - description "A tool that asks for the user's name through an input_required result (SEP-2322)" - - class << self - def call(server_context:, **_args) - content = Mrtr.accepted_content(server_context.input_response("user_name")) - name = content && Mrtr.read(content, :name) - - unless name.is_a?(String) - return MCP::Server::InputRequiredResult.new( - input_requests: { - user_name: { - method: "elicitation/create", - params: { - message: "What is your name?", - requestedSchema: { - type: "object", - properties: { name: { type: "string" } }, - required: ["name"], - }, - }, - }, - }, - ) - end - - MCP::Tool::Response.new([MCP::Content::Text.new("Hello, #{name}!").to_h]) - end - end - end - - class TestInputRequiredResultSampling < MCP::Tool - tool_name "test_input_required_result_sampling" - description "A tool that asks for an LLM completion through an input_required result (SEP-2322)" - - class << self - def call(server_context:, **_args) - text = Mrtr.sampled_text(server_context.input_response("sample_request")) - - unless text - return MCP::Server::InputRequiredResult.new( - input_requests: { - sample_request: { - method: "sampling/createMessage", - params: { - messages: [{ role: "user", content: { type: "text", text: "What is the capital of France?" } }], - maxTokens: 100, - }, - }, - }, - ) - end - - MCP::Tool::Response.new([MCP::Content::Text.new("Sampled: #{text}").to_h]) - end - end - end - - class TestInputRequiredResultListRoots < MCP::Tool - tool_name "test_input_required_result_list_roots" - description "A tool that asks for the client's roots through an input_required result (SEP-2322)" - - class << self - def call(server_context:, **_args) - roots = Mrtr.read(server_context.input_response("roots_request"), :roots) - - unless roots.is_a?(Array) - return MCP::Server::InputRequiredResult.new( - input_requests: { roots_request: { method: "roots/list" } }, - ) - end - - uris = roots.filter_map { |root| Mrtr.read(root, :uri) } - MCP::Tool::Response.new([MCP::Content::Text.new("Roots: #{uris.join(", ")}").to_h]) - end - end - end - - class TestInputRequiredResultRequestState < MCP::Tool - tool_name "test_input_required_result_request_state" - description "A tool whose input_required result carries an opaque requestState (SEP-2322)" - - class << self - def call(server_context:, **_args) - state = Mrtr.parse_state(server_context.request_state) - confirmed = Mrtr.accepted_content(server_context.input_response("confirm")) - - if state && state["kind"] == "request-state" && confirmed - return MCP::Tool::Response.new([MCP::Content::Text.new("state-ok: requestState validated").to_h]) - end - - MCP::Server::InputRequiredResult.new( - input_requests: { - confirm: { - method: "elicitation/create", - params: { - message: "Confirm to continue", - requestedSchema: { - type: "object", - properties: { ok: { type: "boolean" } }, - }, - }, - }, - }, - request_state: JSON.generate({ kind: "request-state", nonce: SecureRandom.hex(8) }), - ) - end - end - end - - class TestInputRequiredResultMultipleInputs < MCP::Tool - tool_name "test_input_required_result_multiple_inputs" - description "A tool that embeds elicitation, sampling, and roots/list inputs in one input_required result (SEP-2322)" - - class << self - def call(server_context:, **_args) - content = Mrtr.accepted_content(server_context.input_response("user_name")) - name = content && Mrtr.read(content, :name) - greeting = Mrtr.sampled_text(server_context.input_response("greeting")) - roots = Mrtr.read(server_context.input_response("client_roots"), :roots) - - if name.is_a?(String) && greeting && roots.is_a?(Array) - return MCP::Tool::Response.new( - [MCP::Content::Text.new("#{greeting} #{name} (#{roots.length} roots)").to_h], - ) - end - - MCP::Server::InputRequiredResult.new( - input_requests: { - user_name: { - method: "elicitation/create", - params: { - message: "What is your name?", - requestedSchema: { - type: "object", - properties: { name: { type: "string" } }, - required: ["name"], - }, - }, - }, - greeting: { - method: "sampling/createMessage", - params: { - messages: [{ role: "user", content: { type: "text", text: "Write a one-word greeting" } }], - maxTokens: 50, - }, - }, - client_roots: { method: "roots/list" }, - }, - request_state: JSON.generate({ kind: "multiple-inputs" }), - ) - end - end - end - - class TestInputRequiredResultMultiRound < MCP::Tool - tool_name "test_input_required_result_multi_round" - description "A tool that needs two elicitation rounds before completing (SEP-2322)" - - class << self - def call(server_context:, **_args) - state = Mrtr.parse_state(server_context.request_state) - - case state && state["round"] - when 1 - content = Mrtr.accepted_content(server_context.input_response("user_name")) - name = content && Mrtr.read(content, :name) - return second_round(name) if name.is_a?(String) - when 2 - content = Mrtr.accepted_content(server_context.input_response("favorite_color")) - color = content && Mrtr.read(content, :color) - if color.is_a?(String) - return MCP::Tool::Response.new([MCP::Content::Text.new("#{state["name"]} likes #{color}").to_h]) - end - end - - first_round - end - - private - - def first_round - MCP::Server::InputRequiredResult.new( - input_requests: { - user_name: { - method: "elicitation/create", - params: { - message: "What is your name?", - requestedSchema: { - type: "object", - properties: { name: { type: "string" } }, - required: ["name"], - }, - }, - }, - }, - request_state: JSON.generate({ round: 1 }), - ) - end - - def second_round(name) - MCP::Server::InputRequiredResult.new( - input_requests: { - favorite_color: { - method: "elicitation/create", - params: { - message: "What is your favorite color?", - requestedSchema: { - type: "object", - properties: { color: { type: "string" } }, - required: ["color"], - }, - }, - }, - }, - request_state: JSON.generate({ round: 2, name: name }), - ) - end - end - end - - class TestInputRequiredResultTamperedState < MCP::Tool - tool_name "test_input_required_result_tampered_state" - description "A tool whose sealed requestState rejects tampered echoes (SEP-2322)" - - class << self - # A tampered `requestState` never reaches this handler: the server-level unsealing rejects it with -32602 - # before dispatch, so the tool body is a plain MRTR flow. - def call(server_context:, **_args) - state = Mrtr.parse_state(server_context.request_state) - confirmed = Mrtr.accepted_content(server_context.input_response("confirm")) - - if state && state["kind"] == "tamper-check" && confirmed - return MCP::Tool::Response.new([MCP::Content::Text.new("requestState integrity verified").to_h]) - end - - MCP::Server::InputRequiredResult.new( - input_requests: { - confirm: { - method: "elicitation/create", - params: { - message: "Confirm to continue", - requestedSchema: { - type: "object", - properties: { ok: { type: "boolean" } }, - }, - }, - }, - }, - request_state: JSON.generate({ kind: "tamper-check", nonce: SecureRandom.hex(8) }), - ) - end - end - end - - class TestInputRequiredResultCapabilities < MCP::Tool - tool_name "test_input_required_result_capabilities" - description "A tool that only embeds input requests the client's declared capabilities can fulfill (SEP-2322)" - - class << self - def call(server_context:, **_args) - capabilities = server_context.client_capabilities || {} - elicited = Mrtr.accepted_content(server_context.input_response("elicit_input")) - sampled = Mrtr.sampled_text(server_context.input_response("sample_input")) - - requests = {} - if Mrtr.read(capabilities, :elicitation) && !elicited - requests[:elicit_input] = { - method: "elicitation/create", - params: { - message: "Provide a value", - requestedSchema: { - type: "object", - properties: { value: { type: "string" } }, - }, - }, - } - end - if Mrtr.read(capabilities, :sampling) && !sampled - requests[:sample_input] = { - method: "sampling/createMessage", - params: { - messages: [{ role: "user", content: { type: "text", text: "Say hello" } }], - maxTokens: 50, - }, - } - end - - if requests.empty? - MCP::Tool::Response.new( - [MCP::Content::Text.new("Inputs: elicit=#{!elicited.nil?}, sample=#{!sampled.nil?}").to_h], - ) - else - MCP::Server::InputRequiredResult.new(input_requests: requests) - end - end - end - end - - class TestLoggingTool < MCP::Tool - tool_name "test_logging_tool" - description "A tool that logs only for requests opting in via the _meta logLevel (SEP-2575)" - - class << self - def call(server_context:, **_args) - # On modern requests the notification is dropped unless `io.modelcontextprotocol/logLevel` authorized it, - # so the call itself is unconditional. - server_context.notify_log_message(data: "Log level honored", level: "info", logger: "conformance") - - MCP::Tool::Response.new([MCP::Content::Text.new("Logging evaluated").to_h]) - end - end - end - - class TestTriggerToolChange < MCP::Tool - tool_name "test_trigger_tool_change" - description "A diagnostic tool that broadcasts notifications/tools/list_changed to listen streams (SEP-2575)" - - class << self - # The broadcast alone exercises the `subscriptions/listen` delivery, so no actual - # tool-list mutation is needed, matching the suite's TypeScript reference fixture. - def call(server_context:, **_args) - server_context.notify_tools_list_changed - - MCP::Tool::Response.new([MCP::Content::Text.new("Mutation triggered").to_h]) - end - end - end - - class TestTriggerPromptChange < MCP::Tool - tool_name "test_trigger_prompt_change" - description "A diagnostic tool that broadcasts notifications/prompts/list_changed to listen streams (SEP-2575)" - - class << self - def call(server_context:, **_args) - server_context.notify_prompts_list_changed - - MCP::Tool::Response.new([MCP::Content::Text.new("Mutation triggered").to_h]) - end - end - end - end - - module Prompts - class TestSimplePrompt < MCP::Prompt - prompt_name "test_simple_prompt" - description "A simple prompt for testing with no arguments" - - class << self - def template(_args, server_context: nil) - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("This is a simple prompt for testing."), - ), - ], - ) - end - end - end - - class TestPromptWithArguments < MCP::Prompt - prompt_name "test_prompt_with_arguments" - description "A prompt with required arguments for testing" - arguments [ - MCP::Prompt::Argument.new(name: "arg1", description: "First test argument", required: true), - MCP::Prompt::Argument.new(name: "arg2", description: "Second test argument", required: true), - ] - - class << self - def template(args, server_context: nil) - arg1 = args.dig(:arg1) || args.dig("arg1") || "" - arg2 = args.dig(:arg2) || args.dig("arg2") || "" - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("Prompt with arguments: arg1='#{arg1}', arg2='#{arg2}'"), - ), - ], - ) - end - end - end - - class TestPromptWithEmbeddedResource < MCP::Prompt - prompt_name "test_prompt_with_embedded_resource" - description "A prompt with an embedded resource for testing" - arguments [ - MCP::Prompt::Argument.new(name: "resourceUri", description: "URI of the resource to embed", required: true), - ] - - class << self - def template(args, server_context: nil) - resource_uri = args.dig(:resourceUri) || args.dig("resourceUri") || "test://example-resource" - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::EmbeddedResource.new( - MCP::Resource::TextContents.new( - uri: resource_uri, - mime_type: "text/plain", - text: "Embedded resource content for testing.", - ), - ), - ), - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("Please process the embedded resource above."), - ), - ], - ) - end - end - end - - class TestPromptWithImage < MCP::Prompt - prompt_name "test_prompt_with_image" - description "A prompt with image content for testing" - - class << self - def template(_args, server_context: nil) - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Image.new(BASE64_1X1_PNG, "image/png"), - ), - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("Please analyze the image above."), - ), - ], - ) - end - end - end - - class TestInputRequiredResultPrompt < MCP::Prompt - prompt_name "test_input_required_result_prompt" - description "A prompt that asks for user context through an input_required result (SEP-2322)" - - class << self - def template(_args, server_context: nil) - content = server_context && Mrtr.accepted_content(server_context.input_response("user_context")) - context = content && Mrtr.read(content, :context) - - unless context.is_a?(String) - return MCP::Server::InputRequiredResult.new( - input_requests: { - user_context: { - method: "elicitation/create", - params: { - message: "Provide context for the prompt", - requestedSchema: { - type: "object", - properties: { context: { type: "string" } }, - required: ["context"], - }, - }, - }, - }, - ) - end - - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("Context: #{context}"), - ), - ], - ) - end - end - end - end - - class Server - DEFAULT_PORT = 9292 - - class DnsRebindingProtection - LOCALHOST_PATTERNS = /\A(localhost|127\.0\.0\.1|\[::1\]|::1)(:\d+)?\z/i.freeze - - def initialize(app) - @app = app - end - - def call(env) - host = env["HTTP_HOST"] || env["SERVER_NAME"] || "" - - unless localhost?(host) - return [ - 403, - { "Content-Type" => "application/json" }, - [{ error: "Forbidden: DNS rebinding protection - invalid Host header '#{host}'" }.to_json], - ] - end - - origin = env["HTTP_ORIGIN"] - if origin && !origin.empty? - begin - origin_host = URI.parse(origin).host.to_s - unless localhost?(origin_host) - return [ - 403, - { "Content-Type" => "application/json" }, - [{ error: "Forbidden: DNS rebinding protection - invalid Origin '#{origin}'" }.to_json], - ] - end - rescue URI::InvalidURIError - return [ - 403, - { "Content-Type" => "application/json" }, - [{ error: "Forbidden: invalid Origin header" }.to_json], - ] - end - end - - @app.call(env) - end - - private - - def localhost?(host) - host.empty? || host.match?(LOCALHOST_PATTERNS) - end - end - - def initialize(port: DEFAULT_PORT) - @port = port - end - - def start - server = build_server - transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - configure_handlers(server) - rack_app = build_rack_app(transport) - - puts <<~MESSAGE - MCP Conformance Server starting on http://localhost:#{@port}/mcp - Use Ctrl-C to stop - MESSAGE - - Rackup::Handler.get("puma").run(rack_app, Port: @port, Host: "localhost", Silent: true) - end - - private - - def build_server - MCP::Server.new( - name: "ruby-sdk-conformance-server", - version: MCP::VERSION, - tools: [ - Tools::TestSimpleText, - Tools::TestImageContent, - Tools::TestAudioContent, - Tools::TestEmbeddedResource, - Tools::TestMultipleContentTypes, - Tools::TestErrorHandling, - Tools::JsonSchema202012Tool, - Tools::TestToolWithLogging, - Tools::TestToolWithProgress, - Tools::TestSampling, - Tools::TestElicitation, - Tools::TestElicitationSep1034Defaults, - Tools::TestElicitationSep1330Enums, - Tools::TestReconnection, - Tools::TestMissingCapability, - Tools::TestInputRequiredResultElicitation, - Tools::TestInputRequiredResultSampling, - Tools::TestInputRequiredResultListRoots, - Tools::TestInputRequiredResultRequestState, - Tools::TestInputRequiredResultMultipleInputs, - Tools::TestInputRequiredResultMultiRound, - Tools::TestInputRequiredResultTamperedState, - Tools::TestInputRequiredResultCapabilities, - Tools::TestStreamingElicitation, - Tools::TestLoggingTool, - Tools::TestTriggerToolChange, - Tools::TestTriggerPromptChange, - ], - prompts: [ - Prompts::TestSimplePrompt, - Prompts::TestPromptWithArguments, - Prompts::TestPromptWithEmbeddedResource, - Prompts::TestPromptWithImage, - Prompts::TestInputRequiredResultPrompt, - ], - resources: resources, - resource_templates: resource_templates, - # A per-boot random key is enough for conformance: every MRTR round trip completes - # within one server process, and sealing keeps the fixture's `requestState` values - # tamper-evident without any tool-level verification code. - request_state_security: MCP::Server::RequestStateSecurity.new(key: SecureRandom.bytes(32)), - capabilities: { - tools: { listChanged: true }, - prompts: { listChanged: true }, - resources: { listChanged: true, subscribe: true }, - logging: {}, - completions: {}, - }, - ) - end - - def resources - [ - MCP::Resource.new( - uri: "test://static-text", - name: "static-text", - description: "A static text resource for testing", - mime_type: "text/plain", - ), - MCP::Resource.new( - uri: "test://static-binary", - name: "static-binary", - description: "A static binary (PNG) resource for testing", - mime_type: "image/png", - ), - MCP::Resource.new( - uri: "test://watched-resource", - name: "watched-resource", - description: "A resource for subscription testing", - mime_type: "text/plain", - ), - ] - end - - def resource_templates - [ - MCP::ResourceTemplate.new( - uri_template: "test://template/{id}/data", - name: "template-resource", - description: "A parameterized resource template for testing", - mime_type: "application/json", - ), - ] - end - - def configure_handlers(server) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - server.server_context = server - - configure_resources_read_handler(server) - configure_subscription_handlers(server) - configure_completion_handler(server) - end - - def configure_resources_read_handler(server) - server.resources_read_handler do |params| - uri = params[:uri].to_s - - case uri - when "test://static-text" - [ - MCP::Resource::TextContents.new( - text: "This is the content of the static text resource.", - uri: uri, - mime_type: "text/plain", - ).to_h, - ] - when "test://static-binary" - [ - MCP::Resource::BlobContents.new( - data: BASE64_1X1_PNG, - uri: uri, - mime_type: "image/png", - ).to_h, - ] - when %r{\Atest://template/(.+)/data\z} - id = Regexp.last_match(1) - content = { id: id, templateTest: true, data: "Data for ID: #{id}" }.to_json - - [ - MCP::Resource::TextContents.new( - text: content, - uri: uri, - mime_type: "application/json", - ).to_h, - ] - else - # Per SEP-2164, an unknown URI answers with -32602 carrying the URI in `error.data`; - # an empty `contents` array is forbidden. - raise MCP::Server::ResourceNotFoundError.new(uri, params) - end - end - end - - def configure_completion_handler(server) - server.completion_handler do |params| - ref = params[:ref] - argument = params[:argument] - value = argument[:value].to_s - - case ref[:type] - when "ref/prompt" - case ref[:name] - when "test_prompt_with_arguments" - candidates = case argument[:name] - when "arg1" - ["value1", "value2", "value3"] - when "arg2" - ["optionA", "optionB", "optionC"] - else - [] - end - values = candidates.select { |v| v.start_with?(value) } - { completion: { values: values, hasMore: false } } - else - { completion: { values: [], hasMore: false } } - end - else - { completion: { values: [], hasMore: false } } - end - end - end - - def configure_subscription_handlers(server) - subscribed_uris = Set.new - - server.resources_subscribe_handler do |params| - subscribed_uris.add(params[:uri].to_s) - end - - server.resources_unsubscribe_handler do |params| - subscribed_uris.delete(params[:uri].to_s) - end - end - - def build_rack_app(transport) - mcp_app = proc do |env| - request = Rack::Request.new(env) - - if request.path_info == "/health" - [200, { "Content-Type" => "application/json" }, ['{"status":"ok"}']] - elsif request.path_info == "/mcp" || request.path_info == "/" - transport.handle_request(request) - else - [404, { "Content-Type" => "application/json" }, ['{"error":"Not found"}']] - end - end - - Rack::Builder.new do - use(DnsRebindingProtection) - run(mcp_app) - end - end - end -end diff --git a/conformance/server_runner.rb b/conformance/server_runner.rb deleted file mode 100644 index 3decbad..0000000 --- a/conformance/server_runner.rb +++ /dev/null @@ -1,101 +0,0 @@ -# frozen_string_literal: true - -# Starts the conformance server and runs `npx @modelcontextprotocol/conformance@alpha` against it. -require "English" -require "net/http" -require_relative "server" - -module Conformance - class ServerRunner - # Timeout for waiting for the Puma server to start. - SERVER_START_TIMEOUT = 20 - SERVER_POLL_INTERVAL = 0.5 - SERVER_HEALTH_CHECK_RETRIES = (SERVER_START_TIMEOUT / SERVER_POLL_INTERVAL).to_i - - def initialize(port: Server::DEFAULT_PORT, scenario: nil, spec_version: nil, verbose: false) - @port = port - @scenario = scenario - @spec_version = spec_version - @verbose = verbose - end - - def run - command = build_command - server_pid = start_server - - run_conformance(command, server_pid: server_pid) - end - - private - - def build_command - expected_failures_yml = File.expand_path("expected_failures.yml", __dir__) - - npx_command = ["npx", "--yes", "@modelcontextprotocol/conformance@alpha", "server", "--url", "http://localhost:#{@port}/mcp"] - npx_command += ["--scenario", @scenario] if @scenario - npx_command += ["--spec-version", @spec_version] if @spec_version - npx_command += ["--verbose"] if @verbose - npx_command += ["--expected-failures", expected_failures_yml] - npx_command - end - - def start_server - puts "Starting conformance server on port #{@port}..." - - server_pid = fork do - Conformance::Server.new(port: @port).start - end - - health_url = URI("http://localhost:#{@port}/health") - ready = false - SERVER_HEALTH_CHECK_RETRIES.times do - begin - response = Net::HTTP.get_response(health_url) - if response.code == "200" - ready = true - break - end - rescue Errno::ECONNREFUSED, Errno::ECONNRESET, Net::ReadTimeout - # not ready yet - end - sleep(SERVER_POLL_INTERVAL) - end - - unless ready - warn("ERROR: Conformance server did not start within #{SERVER_START_TIMEOUT} seconds") - terminate_server(server_pid) - exit(1) - end - - puts "Server ready. Running conformance tests..." - - server_pid - end - - def run_conformance(command, server_pid:) - puts "Command: #{command.join(" ")}\n\n" - - conformance_exit_code = nil - begin - system(*command) - conformance_exit_code = $CHILD_STATUS.exitstatus - ensure - terminate_server(server_pid) - end - - exit(conformance_exit_code || 1) unless conformance_exit_code == 0 - end - - def terminate_server(pid) - Process.kill("TERM", pid) - rescue Errno::ESRCH - # process already exited - ensure - begin - Process.wait(pid) - rescue Errno::ECHILD - # already reaped - end - end - end -end diff --git a/docs/CNAME b/docs/CNAME deleted file mode 100644 index f49a17f..0000000 --- a/docs/CNAME +++ /dev/null @@ -1 +0,0 @@ -ruby.sdk.modelcontextprotocol.io diff --git a/docs/Gemfile b/docs/Gemfile deleted file mode 100644 index eb295d0..0000000 --- a/docs/Gemfile +++ /dev/null @@ -1,15 +0,0 @@ -# frozen_string_literal: true - -# Dependencies for the local docs preview (`rake docs:preview`), kept out of the gem's own Gemfile: -# github-pages mirrors the GitHub Pages runtime that builds the released site -# (jekyll-remote-theme, jekyll-redirect-from, and the Jekyll version Pages actually runs). -source "https://rubygems.org" - -gem "github-pages", group: :jekyll_plugins -gem "webrick" - -# Former default gems that the Jekyll version pinned by github-pages still requires on Ruby 4.0. -gem "base64" -gem "bigdecimal" -gem "csv" -gem "logger" diff --git a/docs/_client/authorization.md b/docs/_client/authorization.md deleted file mode 100644 index 72efd01..0000000 --- a/docs/_client/authorization.md +++ /dev/null @@ -1,405 +0,0 @@ ---- -layout: default -title: Authorization -nav_order: 8 ---- - -# Authorization - -Authorization is handled by the transport layer. This page covers authenticating the HTTP transport, -from custom headers such as bearer tokens to the OAuth 2.1 flows the SDK implements -(PKCE with dynamic client registration, the client credentials grant, and cross-app access). - -## HTTP Authorization - -By default, the HTTP transport layer provides no authentication to the server, but you can provide custom headers if you need authentication. For example, to use Bearer token authentication: - -```ruby -http_transport = MCP::Client::HTTP.new( - url: "https://api.example.com/mcp", - headers: { - "Authorization" => "Bearer my_token" - } -) - -client = MCP::Client.new(transport: http_transport) -client.tools # will make the call using Bearer auth -``` - -You can add any custom headers needed for your authentication scheme, or for any other purpose. The client will include these headers on every request. - -## OAuth 2.1 Authorization - -When an MCP server enforces the [MCP Authorization spec](https://modelcontextprotocol.io/specification/latest/basic/authorization), -pass an `MCP::Client::OAuth::Provider` to the transport instead of a static `Authorization` header. The transport will: - -- Send `Authorization: Bearer ` on every request when a token is available. -- On a `401 Unauthorized`, parse the `WWW-Authenticate` header, discover the authorization server (Protected Resource Metadata + RFC 8414 Authorization Server Metadata), - perform Dynamic Client Registration if needed, run the OAuth 2.1 Authorization Code flow with PKCE (S256), and retry the failed request with the acquired token. -- Fall back to the legacy 2025-03-26 discovery when the server publishes no Protected Resource Metadata, matching the TypeScript and Python SDKs: the MCP server's origin acts - as the authorization base URL, its metadata is fetched from `/.well-known/oauth-authorization-server` and must name that origin as its `issuer` (RFC 8414 Section 3.3), - and when even that is absent the spec's default endpoints `/authorize`, `/token`, and `/register` at the origin are used with PKCE S256 assumed. - When no Protected Resource Metadata candidate serves a JSON object, a request that could not reach the server, or that returned a `5xx` or `429`, - raises `Flow::MetadataUnreachableError` instead of triggering that fallback, and a body over the response cap is refused outright. -- On subsequent 401s with a saved `refresh_token`, exchange it at the token endpoint before falling back to the full interactive flow (RFC 6749 Section 6). - `ClientCredentialsProvider` and `CrossAppAccessProvider` refresh the same way and fall back to their own grant instead; - their refresh also requires the `issuer` the SDK records on the tokens, so tokens stored without it run the grant again. -- On a `403 Forbidden` whose `WWW-Authenticate` header carries `error="insufficient_scope"` (OAuth 2.0 step-up, RFC 6750 Section 3.1 and the MCP scope-selection-strategy), - run a fresh authorization request for the union of the currently granted scope and the scope named in the challenge, then retry the failed request once. - The refresh path is bypassed because refreshing would re-issue the same scope set the server just rejected. A `403` without that challenge is surfaced unchanged. -- Request the `offline_access` scope when `client_metadata[:grant_types]` includes `refresh_token` and the authorization server advertises `offline_access` in its metadata - `scopes_supported` (SEP-2207). This is what lets the server issue the `refresh_token` used above. As an SDK-level safeguard, when the authorization server does not advertise - `offline_access` the scope is also stripped from any other source (challenge, PRM, or provider-supplied scope) so a server that does not support it never receives it. - -```ruby -require "mcp" - -provider = MCP::Client::OAuth::Provider.new( - client_metadata: { - client_name: "My MCP App", - redirect_uris: ["http://localhost:3030/callback"], - grant_types: ["authorization_code", "refresh_token"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:3030/callback", - redirect_handler: ->(authorization_url) { - # Send the user to the authorization URL - typically `Launchy.open(authorization_url)` - # or a manual `puts authorization_url` in CLI tools. - }, - callback_handler: -> { - # Capture the redirect (for example, by running a small HTTP listener on - # `redirect_uri`) and return [code, state] from the query string. - }, -) - -transport = MCP::Client::HTTP.new( - url: "https://api.example.com/mcp", - oauth: provider, -) -client = MCP::Client.new(transport: transport) -client.connect # `initialize` is sent here; if the server replies 401 the OAuth flow runs and the handshake is retried with the acquired token -client.tools -``` - -Required keyword arguments to `Provider.new`: - -- `client_metadata`: Hash sent to the authorization server's Dynamic Client Registration endpoint. Must include `redirect_uris`, `grant_types`, `response_types`, - `token_endpoint_auth_method`. `redirect_uri` (below) must appear in this list, otherwise the constructor raises `Provider::UnregisteredRedirectURIError`. - When `application_type` is omitted, the SDK infers `"native"` or `"web"` from `redirect_uris` per SEP-837 before registering (loopback or custom-scheme URIs are native); - an explicit value always wins. -- `redirect_uri`: String. Must use HTTPS or be a loopback URL (`localhost`, `127.0.0.0/8`, `::1`); other values raise `Provider::InsecureRedirectURIError`. -- `redirect_handler`: Callable invoked with the fully-built authorization `URI`. Typically opens the user's browser. -- `callback_handler`: Callable that returns `[code, state]` or `[code, state, iss]` after the user is redirected back to `redirect_uri`. Returning the 3-element form - (with `iss` set to the RFC 9207 `iss` parameter from the redirect, or `nil` when absent) opts into SEP-2468 issuer validation: a present `iss` must match - the authorization server's issuer, and a missing one is rejected when the server advertises `authorization_response_iss_parameter_supported`. - -Optional keyword arguments: - -- `scope`: Space-separated scopes to request when the server's `WWW-Authenticate` does not specify one. -- `authorization_request_validator`: Callable invoked with an `MCP::Client::OAuth::AuthorizationRequest` before any authorization request is built. - Returning a falsy value abandons the flow with `Flow::AuthorizationRefusedError`. See [Reviewing the authorization request](#reviewing-the-authorization-request). -- `http_client_customizer`: Callable invoked with the Faraday connection the SDK builds for the OAuth flow's own requests, after its defaults and before its origin guard. - See [Customizing the OAuth HTTP Client](#customizing-the-oauth-http-client). -- `storage`: Object responding to `tokens`, `save_tokens(t)`, `client_information`, `save_client_information(info)`. Defaults to `MCP::Client::OAuth::InMemoryStorage`, - which keeps credentials in process memory only. Persisted `client_information` is stamped with an `"issuer"` member binding it to the authorization server that - issued it (SEP-2352): when the server's authorization server changes, the SDK discards the stale registration and its tokens and re-registers automatically - (portable CIMD `client_id`s are kept). Saved `tokens` carry an `"issuer"` member of their own, recording the authorization server that minted them, which is what - lets a later refresh refuse a server the MCP server has since renamed. Treat both hashes as opaque and persist them as-is; a storage that writes out selected members - instead drops these bindings with no error. -- `client_id_metadata_document_url`: URL where you publish a Client ID Metadata Document - (`draft-ietf-oauth-client-id-metadata-document` and the MCP authorization specification). - When the authorization server advertises `client_id_metadata_document_supported: true`, - the SDK uses this URL as the OAuth `client_id` and skips Dynamic Client Registration. - Spec-required: the URL MUST be `https://` with a non-root path and MUST NOT include a fragment, - userinfo, or `.`/`..` segments. The SDK additionally rejects query strings (the draft only marks - them SHOULD NOT include, but the SDK refuses to send any) for `client_id` stability. - Any of these failures raise `Provider::InvalidClientIDMetadataDocumentURLError`. The CIMD document - served at the URL is a separate JSON artifact from the `client_metadata` keyword above: - the DCR `client_metadata` MUST NOT include `client_id`, while the CIMD document MUST include - `client_id` set to the document URL, `client_name`, and `redirect_uris` covering `redirect_uri`. -- `token_request_params`: Hash of String keys and values added to every token request the provider makes, - for parameters the authorization server requires beyond the grant itself, such as Auth0's `audience`. - Defaults to `nil`, which adds nothing. The authorization request is not affected. - A key the SDK sets itself (listed in `Flow::RESERVED_TOKEN_REQUEST_PARAMS`), a Hash that compares keys by identity, - or a value that is not a Hash of Strings is refused with `Flow::InvalidTokenRequestParamsError`, a subclass of `ArgumentError`, - when the provider is built, and the accepted Hash is copied and frozen. - Any provider that defines a `token_request_params` method gets the same treatment on every token request it makes; - the flow checks the returned value by the same rules and raises the same error before the token request is sent. - -{: .warning } -> The OAuth 2.0 Dynamic Client Registration Protocol (RFC 7591) is deprecated as a client registration mechanism as of MCP 2026-07-28 in favor of Client ID Metadata Documents, -> while remaining available for authorization servers that do not support them. Publish a CIMD document and set `client_id_metadata_document_url`; the SDK then prefers it -> automatically wherever the authorization server advertises support. - -To persist credentials across restarts, supply your own storage: - -```ruby -class FileTokenStorage - def initialize(path) - @path = path - end - - def tokens - read["tokens"] - end - - def save_tokens(value) - write("tokens" => value) - end - - def client_information - read["client"] - end - - def save_client_information(value) - write("client" => value) - end - - private - - def read - File.exist?(@path) ? JSON.parse(File.read(@path)) : {} - end - - def write(updates) - File.write(@path, JSON.dump(read.merge(updates))) - end -end - -provider = MCP::Client::OAuth::Provider.new( - # ... required keywords ... - storage: FileTokenStorage.new(File.expand_path("~/.config/my-app/oauth.json")), -) -``` - -### Token Endpoint Errors - -When a token exchange or refresh fails, `MCP::Client::OAuth::Flow::AuthorizationError` includes the HTTP status and -the authorization server's `error` and `error_description` from [RFC 6749 Section 5.2](https://www.rfc-editor.org/rfc/rfc6749#section-5.2). -For example: - -```text -Token endpoint returned status 400. invalid_request: Client must not use multiple authentication methods -``` - -The exception exposes `http_status`, `error`, and `error_description` readers for structured diagnostics. Missing or non-string -diagnostic fields are `nil`; non-JSON responses retain the status-only message. Other authorization failures have `nil` readers. -An `invalid_grant` response still raises `Flow::InvalidGrantError`, a subclass of `Flow::AuthorizationError`, so refresh-token -recovery behavior is unchanged. - -Diagnostic fields are limited to 128 characters for `error` and 512 for `error_description`, including a trailing `...` when -truncated. Characters outside the RFC's printable ASCII set are replaced with spaces, and surrounding whitespace is removed. -The SDK excludes all other response fields, including `error_uri`, and does not include the raw response body in these errors. -Descriptions are provider-controlled text, not guaranteed to be free of sensitive information; apply your application's logging -and redaction policy before persisting them or displaying them to users. - -### Client Credentials Grant - -For a confidential machine-to-machine client (no user, no browser redirect), use `MCP::Client::OAuth::ClientCredentialsProvider` instead of `Provider`. -The transport discovers the authorization server the same way, then exchanges the OAuth 2.1 `client_credentials` grant (RFC 6749 Section 4.4) at -the token endpoint. There is no authorization request, PKCE, or `offline_access`, because the grant is not expected to issue a refresh token (RFC 6749 Section 4.4.3); -a refresh token the authorization server issues anyway is used on the next `401`. - -```ruby -provider = MCP::Client::OAuth::ClientCredentialsProvider.new( - client_id: "my-service", - client_secret: ENV.fetch("MCP_CLIENT_SECRET"), - # token_endpoint_auth_method: "client_secret_basic" (default), "client_secret_post", or "private_key_jwt" - # scope: "mcp:read mcp:write" (optional; used when the server does not advertise scopes) - # token_request_params: { "audience" => "https://api.example.com" } (optional; parameters the authorization server requires) -) - -transport = MCP::Client::HTTP.new(url: "https://api.example.com/mcp", oauth: provider) -``` - -Keyword arguments: - -- `client_id`: Required. `client_secret`: Required with the secret-based methods; the grant is - for confidential clients, so a credential is mandatory. -- `token_endpoint_auth_method`: `"client_secret_basic"` (default), `"client_secret_post"`, - or `"private_key_jwt"` (RFC 7523 JWT client assertion per SEP-1046). `"none"` is rejected - with `ClientCredentialsProvider::InvalidCredentialsError`. -- `private_key`, `signing_algorithm`: Required with `private_key_jwt` - the key (a PEM string - or `OpenSSL::PKey::PKey`, never written to `storage`) signs the client assertion with `"ES256"` - or `"RS256"`; `client_secret` must not be set, because the private key is the credential. -- `scope`, `storage`, `authorization_request_validator`, `token_request_params`, `http_client_customizer`: Optional, same meaning as on `Provider`. - Use `token_request_params` for a parameter the authorization server requires on the `client_credentials` grant, such as Auth0's `audience`. - -### Cross-App Access (JWT Bearer) Grant - -For enterprise MCP deployments where an identity provider (IdP) governs authorization (SEP-990), use `MCP::Client::OAuth::CrossAppAccessProvider` instead of `Provider`. -The client exchanges an IdP-issued ID token for an Identity Assertion Authorization Grant (ID-JAG) at the IdP via RFC 8693 token exchange, then presents the ID-JAG -to the MCP authorization server with the RFC 7523 `jwt-bearer` grant, authenticating with `client_secret_basic`. There is no authorization request, PKCE, DCR, or `offline_access`. -A refresh token the authorization server issues is exchanged on the next `401` with the stored client secret, without calling `assertion_provider` again. -Mirrors `CrossAppAccessProvider` and `requestJwtAuthorizationGrant` in the TypeScript SDK. - -`MCP::Client::OAuth::IDJAGTokenExchange.request` performs the RFC 8693 exchange at the IdP token endpoint. Wrap it in a callable so the same provider can plug into -an enterprise secret store or a test double without changing the transport wiring. - -```ruby -provider = MCP::Client::OAuth::CrossAppAccessProvider.new( - client_id: "my-mcp-client", - client_secret: ENV.fetch("MCP_CLIENT_SECRET"), - assertion_provider: ->(audience:, resource:) { - MCP::Client::OAuth::IDJAGTokenExchange.request( - token_endpoint: "https://idp.example.com/token", - id_token: ENV.fetch("IDP_ID_TOKEN"), - client_id: "my-idp-client", - audience: audience, - resource: resource, - ) - }, - # scope: "mcp:read mcp:write" (optional; used when neither WWW-Authenticate nor PRM specify one) -) - -transport = MCP::Client::HTTP.new(url: "https://api.example.com/mcp", oauth: provider) -``` - -Keyword arguments: - -- `client_id`, `client_secret`: Required. The `jwt-bearer` grant authenticates with `client_secret_basic` at the MCP authorization server. -- `assertion_provider`: Required. Callable invoked as `call(audience:, resource:)` and returning the ID-JAG assertion. - `audience` is the MCP authorization server's validated issuer identifier; `resource` is the canonical MCP server URL (RFC 8707). - Passing both through to `IDJAGTokenExchange.request` covers the common case. -- `scope`, `storage`, `authorization_request_validator`, `token_request_params`, `http_client_customizer`: Optional, same meaning as on `Provider`. - -### Customizing the OAuth HTTP Client - -The requests the OAuth flow makes (Protected Resource Metadata discovery on the MCP server's origin, authorization server metadata discovery, -dynamic client registration, and every token request the flow sends, whether the first exchange, a refresh, or a step-up) go over a Faraday connection of their own, -not over the transport's connection: the transport's is bound to the MCP server URL and carries the `headers:` and the customizer block meant for that server. -To add middleware to the OAuth flow's connection, or to swap its adapter, pass `http_client_customizer:` to the provider: - -```ruby -provider = MCP::Client::OAuth::ClientCredentialsProvider.new( - client_id: "my-service", - client_secret: ENV.fetch("MCP_CLIENT_SECRET"), - http_client_customizer: ->(faraday) { faraday.use MyApp::Middleware::HttpRecorder }, -) -``` - -The callable receives the `Faraday::Connection` after the SDK has applied its defaults and registered the middleware that records the requested URL, -and before the SDK registers its origin guard, the same position the transport's customizer block has on the MCP server connection. -It may be invoked more than once, and from more than one thread at a time, so keep it free of side effects and safe to run concurrently; -today it runs once per authorization attempt, but that is not a promise. -A few constraints follow from the checks described below: - -- Do not add redirect-following middleware. Every destination check runs against the URL as written, so a request that middleware added by the customizer would send - to a different origin after the SDK has recorded the requested URL, whether by following a `3xx` or by rewriting the URL, is refused with `Flow::DestinationMismatchError` - before it reaches the adapter, as is a request that reaches the guard without that record. Middleware inserted ahead of the record with `builder.insert(0, ...)` - that rewrites the URL first or rebuilds the environment is outside the guard, as is following done inside an adapter, so leave both off. -- Leave `Accept-Encoding` unset. The response cap below is measured on decoded bytes, and claiming the header turns Net::HTTP's decoding off. -- Do not add Faraday's `raise_error` middleware. The flow reads statuses itself, both to tell an absent metadata document from a failed request - and to turn a token endpoint error into `Flow::InvalidGrantError`. -- With an adapter that does not stream through `on_data`, the response cap is applied once the body has been buffered rather than as it arrives. -- A middleware that records requests sees the client credentials on token requests (`Authorization: Basic`, `client_secret`, `client_assertion`), refresh tokens, - and the access tokens in token responses; redact them before they reach a log. - -### Communication Security - -When `oauth:` is set, the MCP transport URL and every OAuth-facing URL (PRM, Authorization Server metadata, `authorization_endpoint`, `token_endpoint`, `registration_endpoint`, -`redirect_uri`) must use HTTPS or a loopback host. Non-loopback `http://` URLs are rejected at the SDK boundary so a bearer token is never sent over plain HTTP to a remote host. - -The transport also snapshots the canonicalized origin, path, and query string of the MCP URL at `initialize` time and re-checks them on every outgoing request through -a Faraday middleware that runs after any user-supplied customizer. That means any URL swap raises `MCP::Client::HTTP::InsecureURLError` before the request reaches the adapter, -whether the swap was triggered by -`instance_variable_set(:@url, ...)`, by a Faraday customizer rewriting `url_prefix`, or by a custom middleware rewriting `env.url` (including just `env.url.query`) at request time, -and whether the new URL is `http://` *or* `https://` to a different host or tenant. - -### Discovery URL Destinations - -The scheme rules above say how a URL is contacted, not where it points. Discovery URLs arrive from the network, so the SDK also constrains their destinations. -Both checks run before the request is sent, and neither is configurable. - -- The `resource_metadata` URL in a `WWW-Authenticate` challenge must be on the MCP server's own origin. Protected Resource Metadata describes that server, - so a real deployment publishes it there; requiring it means a `401` cannot aim the first request of the flow at an unrelated host. This is stricter than RFC 9728, - which does not require it. -- The PRM `authorization_servers` entry and the `authorization_endpoint`, `token_endpoint`, and `registration_endpoint` from Authorization Server metadata must not be - IP literals in a private, loopback, link-local, or unique-local range, per the SSRF precaution in [RFC 9728 Section 7.7](https://www.rfc-editor.org/rfc/rfc9728#section-7.7). - The blocked ranges are `0.0.0.0/8`, `10.0.0.0/8`, `100.64.0.0/10`, `127.0.0.0/8`, `169.254.0.0/16`, `172.16.0.0/12`, `192.168.0.0/16`, `::/96`, `fc00::/7`, - and `fe80::/10`, along with the IPv4-mapped IPv6 spellings of each and the `localhost` name. -- That range check is skipped when the MCP server URL you configured is itself on such an address. Pointing the client at a private network is a deliberate act, - and the authorization server for it usually lives on the same network, so `http://localhost` development and deployments that never leave a corporate network keep working. - -The range check compares IP literals and does not resolve hostnames, so it cannot recognize an internal service that is named rather than addressed, -such as `https://vault.corp.internal/`. Resolving names here would not close that gap either, because the address the SDK looked up need not be the one -the HTTP client connects to a moment later. The same-origin rule is what protects the `resource_metadata` URL, which is the only one of these a server supplies directly. - -On the connection the SDK builds, a middleware that would send a request to a different origin, by following a `3xx` or by rewriting the URL, is refused before the request -goes out (see [Customizing the OAuth HTTP Client](#customizing-the-oauth-http-client)). A connection supplied through `MCP::Client::OAuth::Flow.new(http_client_factory:)` -replaces that one, the provider's `http_client_customizer` and the guard included, so do not add redirect-following middleware to it: every check above runs against -the URL as written, and a connection that follows a `3xx` on its own would reach hosts these rules just refused. -A factory that wants to keep them can return `MCP::Client::OAuth::Flow.build_http_client(customizer)`, the connection the SDK builds for itself. - -The SDK also bounds what those endpoints may return. A discovery, dynamic client registration, token, or token exchange response is refused once it passes 4 MiB, -measured as the body arrives rather than after it has been buffered, so a compressed body that expands past the limit is refused partway through the expansion. -Unlike the transport's `max_message_bytes:`, this limit is not configurable: these documents run to kilobytes in normal operation, and a connection supplied through -`http_client_factory:` is bounded as well, so there is no way to opt out of it. - -### Reviewing the authorization request - -The checks above constrain where the SDK will send a request. What they cannot decide is whether the authorization server an MCP server names is one you want -your users signing in to. That choice belongs to the MCP server: it publishes `authorization_servers` in its Protected Resource Metadata and states the scopes -it wants in `scopes_supported` or in the `WWW-Authenticate` challenge. An authorization server is legitimately a different origin from the resource it protects, -so no origin rule can settle the question, and validating that a token was issued for the intended audience is a responsibility the specification places on -MCP servers rather than on clients. - -`authorization_request_validator` is where an application that *does* know which providers its users deal with can say so: - -```ruby -ALLOWED_ISSUERS = ["https://login.example.com", "https://accounts.google.com"] - -provider = MCP::Client::OAuth::Provider.new( - # client_metadata:, redirect_uri:, redirect_handler:, and callback_handler: as in the first example. - authorization_request_validator: ->(request) { - ALLOWED_ISSUERS.include?(request.authorization_server) - }, -) -``` - -The argument is an `MCP::Client::OAuth::AuthorizationRequest` carrying `authorization_server` (the selected issuer), `scopes` (an Array, empty when neither -the challenge nor the metadata named any), `server_url`, and `resource`. It is one object rather than keyword arguments so that later revisions of the specification -can add to it without changing the shape you wrote. Only the named readers are the contract. The positional access a `Struct` also happens to provide -(`request[0]`, `to_a`, `each`) is not, and can break when the representation changes. - -`server_url` is the URL the transport was configured with, verbatim; `resource` is the value actually sent as the RFC 8707 `resource`, which is that URL canonicalized -(fragment and userinfo dropped, scheme and host lowercased, a default port removed) or, when the Protected Resource Metadata advertises one, -the canonicalized value from there. That advertised value may name a parent path, so a server at `https://api.example.com/mcp` can legitimately produce -a `resource` of `https://api.example.com`. Match on `server_url` when you mean the server you configured. - -Compare the issuer as a whole string, the way the SDK compares it everywhere else, rather than picking its host out: multi-tenant providers tell tenants apart by path, -and a legacy authorization server whose metadata never named an issuer arrives as `nil`, which an exact comparison refuses instead of raising. - -The provider is only half of the decision. The MCP server chose the scopes too, so a request naming a provider you allow can still ask for more than that server has -any business asking for. `scopes` rides on the request so that a host with a policy per server can apply it: - -```ruby -ALLOWED_SCOPES = { "https://api.example.com/mcp" => ["mcp:read", "mcp:write"] } - -provider = MCP::Client::OAuth::Provider.new( - # client_metadata:, redirect_uri:, redirect_handler:, and callback_handler: as in the first example. - authorization_request_validator: ->(request) { - ALLOWED_ISSUERS.include?(request.authorization_server) && request.scopes.all? { |scope| ALLOWED_SCOPES.fetch(request.server_url, []).include?(scope) } - }, -) -``` - -A host with a user to ask can put the decision to them instead. The request carries what such a prompt has to name: the provider, the scopes, and the server that asked for them. - -It runs on all three grants, after that server's metadata has been fetched (which is where the validated issuer comes from) and before any registration, credential, -or user reaches it: on the authorization-code grant before dynamic client registration and before any browser is opened, -and on the JWT bearer grant before `assertion_provider` is invoked, since obtaining an ID-JAG tells your identity provider which authorization server -the assertion is for. Refusing therefore leaves nothing registered at, and no assertion minted for, the authorization server you rejected. -Returning a falsy value raises `Flow::AuthorizationRefusedError`. It subclasses `Flow::AuthorizationError`, so a rescue written for that still catches it, -while rescuing the narrower class tells a refusal by your own policy apart from a network or metadata failure. - -The hook decides whether to proceed, not what to ask for: the scopes are passed to the authorization server unchanged either way, because the specification -requires a client to treat the scopes in the challenge as authoritative for the operation. Leaving it unset authorizes whatever the server asked for, -which is what every MCP SDK does today. - -It is asked when a new grant is requested, not on every token refresh, which happens unattended and against an authorization server you already answered for. -An authorization server that changes between authorization and refresh is caught instead: the SDK records which one issued the tokens, and `refresh!` refuses to -present a refresh token to a different one, even when the client identity is portable across authorization servers as a Client ID Metadata Document URL is. -The transport answers that refusal by running a full authorization, which brings the new authorization server back here for you to accept or refuse. -Tokens stored before this behavior shipped carry no issuer and keep refreshing; the binding applies from their next authorization. diff --git a/docs/_client/cancellation.md b/docs/_client/cancellation.md deleted file mode 100644 index 2a9409c..0000000 --- a/docs/_client/cancellation.md +++ /dev/null @@ -1,71 +0,0 @@ ---- -layout: default -title: Cancellation -nav_order: 5 ---- - -# Cancellation - -`MCP::Client` lets the caller cancel a request it has already issued, -per the [MCP `notifications/cancelled` utility](https://modelcontextprotocol.io/specification/latest/basic/patterns/cancellation). -The recommended pattern is to pass -an `MCP::Cancellation` token into the request method, run the request on a worker thread, and call -`cancellation.cancel(reason:)` from another thread. The cancelling thread sends `notifications/cancelled` to -the server, and the calling thread is woken up with `MCP::CancelledError`: - -```ruby -client = MCP::Client.new(transport: transport) -cancellation = MCP::Cancellation.new - -Thread.new do - client.call_tool(name: "slow_tool", arguments: {}, cancellation: cancellation) -rescue MCP::CancelledError - # cleanup -end - -# Later, from another thread: -cancellation.cancel(reason: "user pressed cancel") -``` - -All request methods (`tools`, `list_tools`, `resources`, `list_resources`, `resource_templates`, `list_resource_templates`, -`prompts`, `list_prompts`, `call_tool`, `read_resource`, `get_prompt`, `complete`, `discover`, `ping`) accept the `cancellation:` keyword. -Request ids are managed internally, so the token is the only thing a caller needs to cancel a request. - -{: .note } -> When a cancel wins the race, the SDK's worker thread that is blocked on the underlying I/O is *not* force-killed; -> it stays blocked until the transport actually returns (or the user closes the transport). This matches the server-side -> `StreamableHTTPTransport#send_request` trade-off. For `Client::HTTP` -> the leak resolves as soon as the server sends any response; for `Client::Stdio` you may need to call `client.transport.close` -> to free the thread if the server stops responding entirely. The cancel-dispatch thread waits for the worker's send-boundary signal -> (`&on_sent` from `send_request`) before issuing `notifications/cancelled`, so the cancel is held until the worker has at -> least committed to writing the request; while the worker is wedged the cancel notification is deferred along with it. - -{: .note } -> On a [modern](/client/lifecycle/) connection the cancel notification cannot reach the in-flight -> request: correlating the two is a session mechanic of the handshake lifecycle, and modern requests -> are sessionless single POST exchanges. The local effect is unchanged - the calling thread still -> raises `MCP::CancelledError` - but the server runs the request to completion. - -## Wire-order guarantees - -`Client::Stdio` serializes the request write and any subsequent `notifications/cancelled` write through a single `@write_mutex`, -so the server is guaranteed to read the request line before the cancel line. - -`Client::HTTP` cannot offer the same wire-arrival guarantee. Faraday's synchronous `post` does not expose a post-write / pre-response hook, -so the SDK yields just before the request POST is dispatched. After the yield, the cancel-dispatch thread issues a separate `notifications/cancelled` POST -on its own connection, and the two POSTs may overlap on the network. The spec is satisfied either way: the sender has already issued the request and -still believes it to be in-progress when issuing the cancel ([MCP cancellation spec](https://modelcontextprotocol.io/specification/latest/basic/patterns/cancellation)), -and on the receiver side, "receivers MAY ignore a cancellation notification whose `requestId` is unknown" covers the case where the cancel POST -happens to arrive first. The calling thread raises `MCP::CancelledError` regardless of network ordering. - -## Custom transports - -Custom transports that want to support `cancellation:` must implement `send_notification(notification:)` so `notifications/cancelled` can be delivered. -They should also accept the optional block passed to `send_request(request:, &on_sent)` and call it once the request bytes have been handed off to the wire -(under a write-side mutex for stdio-style transports, immediately before the synchronous round-trip for HTTP-style transports). -The cancel-dispatch thread waits on this signal before sending `notifications/cancelled`. Transports that do not invoke the block fall back to waiting for -the worker thread to terminate, which preserves wire-order at the cost of delaying the cancel notification until the request has fully completed. - -## Server Side - -How servers observe cancellation in their handlers is documented on the server [Cancellation](/server/cancellation/) page. diff --git a/docs/_client/index.md b/docs/_client/index.md deleted file mode 100644 index 2e3077c..0000000 --- a/docs/_client/index.md +++ /dev/null @@ -1,47 +0,0 @@ ---- -layout: default -title: Overview -nav_order: 1 -permalink: /client/ -redirect_from: - - /building-clients.html - - /building-clients/ ---- - -# Building an MCP Client - -The `MCP::Client` class provides an interface for interacting with MCP servers. - -This class supports: - -- Lifecycle negotiation and connection via `MCP::Client#connect`, adopting the modern lifecycle - when the server serves it; see [Lifecycle](/client/lifecycle/) -- Server discovery via the `server/discover` method (`MCP::Client#discover`); see [Explicit Discovery](/client/lifecycle/#explicit-discovery) -- Liveness check via the `ping` method (`MCP::Client#ping`), and automatic answers to server pings; - see [Answering Server Pings](/client/ping/#answering-server-pings) -- Tool listing via the `tools/list` method (`MCP::Client#tools`) -- Tool invocation via the `tools/call` method (`MCP::Client#call_tool`) -- Resource listing via the `resources/list` method (`MCP::Client#resources`) -- Resource template listing via the `resources/templates/list` method (`MCP::Client#resource_templates`) -- Resource reading via the `resources/read` method (`MCP::Client#read_resource`) -- Prompt listing via the `prompts/list` method (`MCP::Client#prompts`) -- Prompt retrieval via the `prompts/get` method (`MCP::Client#get_prompt`) -- Completion requests via the `completion/complete` method (`MCP::Client#complete`); see [Completion](/server/completion/) -- Automatic driving of multi round-trip `input_required` results once `on_elicitation`, `on_sampling`, - or `on_roots` handlers are registered; see [Multi Round-Trip Requests](/client/mrtr/) -- Cancellation of in-flight requests via the `cancellation:` keyword; see [Cancellation](/client/cancellation/) -- Cursor-based page iteration on the `list_*` methods and whole-collection fetching with - the `max_pages` guard; see [Pagination](/client/pagination/) -- Automatic JSON-RPC 2.0 message formatting -- UUID request ID generation - -Clients are initialized with a [transport layer](/client/transports/) instance that handles the low-level communication mechanics. -Authorization is handled by the transport layer; see [Authorization](/client/authorization/). - -## Tool Objects - -The client provides a wrapper class for tools returned by the server: - -- `MCP::Client::Tool` - Represents a single tool with its metadata - -This class provides easy access to tool properties like name, description, input schema, and output schema. diff --git a/docs/_client/lifecycle.md b/docs/_client/lifecycle.md deleted file mode 100644 index 632db50..0000000 --- a/docs/_client/lifecycle.md +++ /dev/null @@ -1,78 +0,0 @@ ---- -layout: default -title: Lifecycle -nav_order: 3 ---- - -# Lifecycle - -Before sending requests, a client establishes its lifecycle with the server: the classic `initialize` handshake -on legacy protocol versions, or the sessionless modern lifecycle of MCP 2026-07-28. -This page covers `MCP::Client#connect` and how it negotiates between the two. - -## Handshake - -Call `MCP::Client#connect` to perform the MCP [initialization handshake](https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#initialization) before sending any other requests. The client sends an `initialize` request through the transport, followed by the required `notifications/initialized` notification, and caches the server's `InitializeResult` (protocol version, capabilities, server info, instructions): - -```ruby -client.connect -# => { "protocolVersion" => "2025-11-25", "capabilities" => {...}, "serverInfo" => {...} } - -client.connected? # => true -client.server_info # => cached InitializeResult -``` - -`connect` accepts optional `client_info:`, `protocol_version:`, and `capabilities:` keyword arguments. It is idempotent: a second call returns the cached result without contacting the server. After `close`, state is cleared and `connect` will handshake again. - -This applies to both the Stdio and HTTP transports described on the [Transports](/client/transports/) page. - -By default `connect` [negotiates the lifecycle](#lifecycle-negotiation) first and performs this handshake -only when the server does not serve the modern lifecycle, or when `mode: :legacy` or a legacy `protocol_version:` forces it. - -## Lifecycle Negotiation - -`MCP::Client#connect` selects the protocol lifecycle automatically by default: on the bundled -`MCP::Client::HTTP` and `MCP::Client::Stdio` transports it probes [`server/discover`](/server/discover/) first and adopts -the stateless modern lifecycle (MCP 2026-07-28, SEP-2575) when the server serves it, falling back to -the classic `initialize` handshake otherwise. Custom transports whose `connect` does not declare -a `mode:` keyword always receive the classic call shape, unchanged. - -```ruby -client.connect # negotiate automatically (default) -client.connect(mode: :modern) # require the modern lifecycle; fails on legacy-only servers -client.connect(mode: :legacy) # force the classic initialize handshake -client.connect(protocol_version: "2025-11-25") # an explicit legacy version pins the handshake, no probe -``` - -Prefer `mode: :legacy` for spawn-per-invocation CLI tools (the probe adds a round trip per process) -and when using server-initiated requests (`on_elicitation` / `on_sampling`), which exist only on -the legacy lifecycle. - -Because the raw `connect` return value and `MCP::Client#server_info` mirror the wire result, -their shape depends on the negotiated lifecycle: `InitializeResult` (`protocolVersion`, -top-level `serverInfo`) on legacy, `DiscoverResult` (`supportedVersions`, `ttlMs`/`cacheScope`) -on modern. Code that should work against both lifecycles can use the era-independent readers instead: - -```ruby -client.protocol_version # negotiated or adopted version, either lifecycle -client.server_capabilities # capabilities Hash, either lifecycle -client.instructions # instructions text, either lifecycle -client.server_implementation # server name/version; nil when a modern server does not identify itself -``` - -Troubleshooting: if `server_info["protocolVersion"]` starts returning `nil` after a server you connect to was upgraded, -the server now serves the modern lifecycle and the automatic negotiation adopted it. -Pass `mode: :legacy` for an immediate return to the previous behavior, or switch to the readers above for a permanent fix. - -## Explicit Discovery - -`MCP::Client#discover` sends `server/discover` directly: sessionless capability discovery -that works before (or instead of) `connect`. It returns an `MCP::Client::DiscoverResult` struct -exposing `supported_versions`, `capabilities`, `server_info`, `instructions`, and -the `ttl_ms` / `cache_scope` cache hints; see the server [Discovery](/server/discover/) page -for the wire shapes. - -```ruby -result = client.discover -result.supported_versions # => ["2026-07-28"] -``` diff --git a/docs/_client/mrtr.md b/docs/_client/mrtr.md deleted file mode 100644 index 4a68e5f..0000000 --- a/docs/_client/mrtr.md +++ /dev/null @@ -1,62 +0,0 @@ ---- -layout: default -title: Multi Round-Trip Requests -nav_order: 4 -redirect_from: - - /client/multi-round-trip-results/ ---- - -# Multi Round-Trip Requests - -MCP 2026-07-28 replaces in-flight server-to-client requests with Multi Round-Trip Requests (SEP-2322): instead of issuing `sampling/createMessage`, `roots/list`, -or `elicitation/create` while a request is being processed, a server may answer with a result whose `resultType` is `"input_required"`, carrying an `inputRequests` map -and an opaque `requestState`; the client fulfills the requests and re-issues the original request with `inputResponses` and the echoed `requestState`. - -## Automatic Driving - -The Ruby client drives such results automatically: once a handler is registered through `on_elicitation`, `on_sampling`, or `on_roots`, the `call_tool`, `get_prompt`, -and `read_resource` methods fulfill the embedded requests and re-issue the original request with `inputResponses` plus the echoed `requestState`, capped at `input_required_max_rounds` -(10 by default, matching the TypeScript and Python SDKs). - -```ruby -client = MCP::Client.new(transport: transport) -client.connect(capabilities: { elicitation: { form: {} } }) - -client.on_elicitation do |params| - { action: "accept", content: { name: "Alice" } } -end - -# The input_required round trips are driven automatically; this returns the final result. -response = client.call_tool(name: "collect_name", arguments: {}) -``` - -Declare the capabilities matching the registered handlers on `connect`: a server embeds only the request kinds -the client declared. - -## Manual Driving - -Without a matching handler, `MCP::Client::InputRequiredError` is raised instead of returning the result as if it were final; -the error exposes `input_requests`, `request_state`, and the raw `result` for manual driving via the `input_responses:` and `request_state:` keywords: - -```ruby -begin - client.call_tool(name: "collect_name", arguments: {}) -rescue MCP::Client::InputRequiredError => error - answers = error.input_requests.transform_values { |request| answer_for(request) } - - client.call_tool( - name: "collect_name", - arguments: {}, - input_responses: answers, - request_state: error.request_state, - ) -end -``` - -`MCP::ResultType::COMPLETE` and `MCP::ResultType::INPUT_REQUIRED` are provided for forward compatibility. -Servers on legacy protocol versions never send `resultType`, so existing behavior is unchanged. - -## Server Side - -Authoring `input_required` results with `InputRequiredResult`, securing `requestState`, `resultType` stamping, and the legacy fulfillment -shim that serves pre-2026 clients are documented on the server [Multi Round-Trip Requests](/server/mrtr/) page. diff --git a/docs/_client/pagination.md b/docs/_client/pagination.md deleted file mode 100644 index 1f89c02..0000000 --- a/docs/_client/pagination.md +++ /dev/null @@ -1,80 +0,0 @@ ---- -layout: default -title: Pagination -nav_order: 7 ---- - -# Pagination - -Servers may paginate `tools/list`, `prompts/list`, `resources/list`, and `resources/templates/list` responses -per the [MCP pagination utility](https://modelcontextprotocol.io/specification/latest/server/utilities/pagination). -Cursor tokens are opaque to clients: the server decides page size, and the client follows `nextCursor` until the server omits it. - -## Iterating Pages - -`MCP::Client` exposes `list_tools`, `list_prompts`, `list_resources`, and `list_resource_templates`. -**Each call issues exactly one `*/list` JSON-RPC request and returns exactly one page** - not the full collection. -The returned result object (`MCP::Client::ListToolsResult` etc.) exposes the page items and the next cursor -as method accessors; a `meta` accessor also mirrors the response's `_meta` field: - -```ruby -client = MCP::Client.new(transport: transport) - -cursor = nil -loop do - page = client.list_tools(cursor: cursor) - page.tools.each { |tool| process(tool) } - cursor = page.next_cursor - break unless cursor -end -``` - -The same pattern applies to `list_prompts` (`page.prompts`), `list_resources` (`page.resources`), and -`list_resource_templates` (`page.resource_templates`). `next_cursor` is `nil` on the final page. - -Because a single call returns a single page, how many items come back depends on the server's `page_size` configuration: - -| Server `page_size` | `client.list_tools(cursor: nil)` | -|--------------------|---------------------------------------------------------------------| -| Not set (default) | Returns every item in one response. `next_cursor` is `nil`. | -| Set to `N` | Returns the first `N` items. `next_cursor` is set for continuation. | - -If your application needs the complete collection regardless of how the server is configured, either loop on -`next_cursor` as shown above, or use the whole-collection methods described below. - -## Fetching the Complete Collection - -`client.tools`, `client.resources`, `client.resource_templates`, and `client.prompts` auto-iterate -through all pages and return a plain array of items, guaranteeing the full collection regardless -of the server's `page_size` setting. When a server paginates, they issue multiple JSON-RPC round -trips per call. Two guards keep that loop finite: it stops when the server returns a `nextCursor` -it has already sent, and it stops after `max_pages` pages. - -```ruby -tools = client.tools # => Array of every tool on the server. -``` - -`MCP::Client.new` accepts an optional `max_pages:` keyword that caps how many pages these methods -will walk. It defaults to `1_000`; a server that keeps offering a fresh `nextCursor` past that -point raises `MCP::Client::PaginationLimitError` rather than being followed indefinitely. Raise it -if you legitimately expect more pages than that. - -Use these when you want the complete list; use `list_tools(cursor:)` etc. when you need -fine-grained iteration (e.g. to stream-process pages without loading everything into memory). - -## Cache Hints - -Per SEP-2549, list and read results can carry cache hints telling clients how long a result stays fresh (`ttlMs`) -and whether shared intermediaries may cache it (`cacheScope`); see -[List Result Caching](/server/pagination/#list-result-caching) on the server page for how they are emitted. -On the client, the values are surfaced on the paginated result structs as `ttl_ms` and `cache_scope`: - -```ruby -page = client.list_tools -page.ttl_ms # => 60000 (nil when the server sent no hint) -page.cache_scope # => "private" -``` - -## Server Side - -Enabling pagination with `page_size:` is documented on the server [Pagination](/server/pagination/) page. diff --git a/docs/_client/ping.md b/docs/_client/ping.md deleted file mode 100644 index f546afe..0000000 --- a/docs/_client/ping.md +++ /dev/null @@ -1,49 +0,0 @@ ---- -layout: default -title: Ping -nav_order: 6 ---- - -# Ping - -The [MCP `ping` utility](https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/ping) -allows either side of the connection to verify that the peer is still responsive. - -{: .note } -> MCP 2026-07-28 removes `ping` from the protocol (SEP-2575): requests of -> the [modern lifecycle](/client/lifecycle/) are single POST exchanges whose connection itself -> signals liveness. `#ping` sends the request regardless of the negotiated lifecycle, -> so on a modern connection a conforming server (the Ruby SDK server included) rejects it -> with `-32601` Method not found and `ServerError` is raised; ping is a handshake-lifecycle utility. - -`MCP::Client` exposes `ping` to send a ping to the server: - -```ruby -client = MCP::Client.new(transport: transport) -client.ping # => {} on success -``` - -`#ping` raises `MCP::Client::ServerError` when the server returns a JSON-RPC error. -It raises `MCP::Client::ValidationError` when the response `result` is missing or -is not a Hash (matching the spec requirement that `result` be an object). -Transport-level errors (for example, `MCP::Client::Stdio`'s `read_timeout:` firing) -propagate as exceptions raised by the transport layer. - -## Answering Server Pings - -On handshake-lifecycle connections a server may ping the client the same way, and the client answers automatically with -the empty result - no handler is needed. Over HTTP a ping reaches the client only on a stream that is already open -(the SSE response of an in-flight POST, or the GET listening stream); the client never opens a stream just to receive pings. -Over stdio, a ping that arrives while a response is awaited is answered inline; between requests it is answered when -the next request starts reading. The answer is best effort: a pong that cannot be written (for example, over a broken pipe) is -dropped rather than failing the request whose response is being read. Independently of pings, consider setting `read_timeout:` -on `MCP::Client::Stdio`, since a server that never answers otherwise holds the read until the process exits. - -To answer pings yourself, register `transport.on_server_request("ping")` on `MCP::Client::HTTP`; it replaces -the automatic answer and, like any handler registered there, opens the standalone GET listening stream on `connect`, -as described on the [Transports](/client/transports/#server-to-client-requests-elicitation) page. - -## Server Side - -How servers answer `ping` requests and ping the client themselves is documented on -the server [Ping](/server/ping/) page. diff --git a/docs/_client/transports.md b/docs/_client/transports.md deleted file mode 100644 index d69e5e9..0000000 --- a/docs/_client/transports.md +++ /dev/null @@ -1,285 +0,0 @@ ---- -layout: default -title: Transports -nav_order: 2 ---- - -# Transports - -`MCP::Client` is transport-agnostic: it sends every request through the transport instance it is built with. -This page covers the bundled [stdio](#stdio-transport-layer) and [Streamable HTTP](#http-transport-layer) transports, -their sessions and server-to-client request handling, and the interface a custom transport must implement. - -## Stdio Transport Layer - -Use the `MCP::Client::Stdio` transport to interact with MCP servers running as subprocesses over standard input/output. - -`MCP::Client::Stdio.new` accepts the following keyword arguments: - -| Parameter | Required | Description | -|---|---|---| -| `command:` | Yes | The command to spawn the server process (e.g., `"ruby"`, `"bundle"`, `"npx"`). | -| `args:` | No | An array of arguments passed to the command. Defaults to `[]`. | -| `env:` | No | A hash of environment variables to set for the server process. Defaults to `nil`. | -| `read_timeout:` | No | Timeout in seconds for waiting for a server response. Defaults to `nil` (no timeout). | -| `max_line_bytes:` | No | Maximum byte length of a single newline-delimited response frame. A frame that reaches this limit without a newline is rejected as a transport error, preventing unbounded memory growth from a server that never emits a newline. Defaults to `4 * 1024 * 1024` (4 MiB). | - -Example usage: - -```ruby -stdio_transport = MCP::Client::Stdio.new( - command: "bundle", - args: ["exec", "ruby", "path/to/server.rb"], - env: { "API_KEY" => "my_secret_key" }, - read_timeout: 30 -) -client = MCP::Client.new(transport: stdio_transport) - -# Perform the MCP initialization handshake before sending any requests. -client.connect - -# List available tools. -tools = client.tools -tools.each do |tool| - puts "Tool: #{tool.name} - #{tool.description}" -end - -# Call a specific tool. -response = client.call_tool( - tool: tools.first, - arguments: { message: "Hello, world!" } -) - -# Close the transport when done. -stdio_transport.close -``` - -The stdio transport automatically handles: - -- Spawning the server process with `Open3.popen3` -- MCP protocol initialization handshake (`initialize` request + `notifications/initialized`) -- JSON-RPC 2.0 message framing over newline-delimited JSON -- Answering server `ping` requests; see [Answering Server Pings](/client/ping/#answering-server-pings) - -{: .note } -> `ping` is the only server-to-client request answered over stdio. A wire-level `elicitation/create` -> or `sampling/createMessage` is ignored on this transport, so a server that sends one waits for an answer -> that never comes; use Streamable HTTP for those, as described below. The SEP-2322 `input_required` route, -> which is how the modern lifecycle asks for the same input, works on every transport, so `on_elicitation` -> and `on_sampling` handlers still fire over stdio; see [Multi Round-Trip Requests](/client/mrtr/). - -## HTTP Transport Layer - -Use the `MCP::Client::HTTP` transport to interact with MCP servers using simple HTTP requests. - -You'll need to add `faraday` as a dependency in order to use the HTTP transport layer, and `event_stream_parser` -to read SSE (`text/event-stream`) responses. -Whether a response is JSON or SSE is the server's choice, made for each response, and a client must accept both, -so a client written for arbitrary servers needs both gems. This SDK's own server picks SSE by default and always -does on the modern lifecycle, and the listening stream that `on_elicitation` and `on_sampling` open is SSE as well. -`event_stream_parser` is loaded on the first SSE response, so it can be left out only against a server known to -answer with JSON alone, such as this SDK's server in [JSON response mode](/server/transports/#json-response-mode) -serving handshake-lifecycle clients, and only while no listening stream is opened: - -```ruby -gem "mcp" -gem "faraday", ">= 2.0" -gem "event_stream_parser", ">= 1.0" # optional, required only for SSE responses -``` - -Example usage: - -```ruby -http_transport = MCP::Client::HTTP.new(url: "https://api.example.com/mcp") -client = MCP::Client.new(transport: http_transport) - -# Perform the MCP initialization handshake before sending any requests. -client.connect - -# List available tools -tools = client.tools -tools.each do |tool| - puts <<~TOOL_INFORMATION - Tool: #{tool.name} - Description: #{tool.description} - Input Schema: #{tool.input_schema} - TOOL_INFORMATION -end - -# Call a specific tool -response = client.call_tool( - tool: tools.first, - arguments: { message: "Hello, world!" } -) - -# Call a tool with progress tracking. -response = client.call_tool( - tool: tools.first, - arguments: { count: 10 }, - progress_token: "my-progress-token" -) -``` - -The server sends `notifications/progress` during execution; the bundled transports do not currently -expose these notifications to application code, so the token's effect is visible on the server side. -See the [Progress](/server/progress/) page. - -`MCP::Client::HTTP.new` accepts an optional `max_message_bytes:` keyword that caps the bytes buffered in memory for a single message from the server - -an SSE event or a JSON response body. A message that reaches this limit before completing is rejected as a transport error, preventing unbounded memory growth from -a server that never terminates an SSE event. It defaults to `4 * 1024 * 1024` (4 MiB); raise it if your server returns larger responses. - -`MCP::Client::HTTP.new` also accepts `max_reconnection_wait:`, a budget in seconds for resuming a closed SSE stream. It gates every wait between reconnection attempts, -and what is left of it becomes the read timeout of each resumed stream. The server chooses that wait through the SSE `retry:` field, and resuming happens on the calling thread, -so without a budget a server answering with a large `retry:` parks a thread of your application for as long as it likes. It defaults to `300` (5 minutes). -The server's `retry:` is never shortened: when honoring it would run past the budget, the client stops trying to resume and raises instead, -the same thing it already does once the reconnection attempts are used up. A floor of 100ms applies to each wait, so a `retry: 0` cannot spin -the listening stream's reconnect loop; waiting longer than the server asked for is explicitly allowed by the SSE reconnection algorithm the spec points at. - -### Sessions - -After `connect` succeeds, the HTTP transport captures the `Mcp-Session-Id` header and `protocolVersion` from the response and includes them on subsequent requests. Both are exposed on the transport as transport-specific state: - -```ruby -http_transport.session_id # => "abc123..." -http_transport.protocol_version # => "2025-11-25" -``` - -If the server terminates the session, subsequent requests return HTTP 404 and the transport raises `MCP::Client::SessionExpiredError` (a subclass of `RequestHandlerError`). Session state is cleared automatically; callers should start a new session by calling `connect` again. - -To explicitly terminate a session (e.g., when the client application is shutting down), call `close`. The transport sends an HTTP DELETE to the MCP endpoint with the session header and clears local session state. A `405 Method Not Allowed` response (server doesn't support client-initiated termination) or `404 Not Found` (session already terminated server-side) is treated as success. Other errors - 5xx, authentication failures, connection errors - propagate to the caller. Local session state is cleared either way. Calling `close` without an active session is a no-op. - -```ruby -http_transport.close -``` - -These are handshake-lifecycle mechanics: on a [modern](/client/lifecycle/) connection there is -no session to capture - `session_id` stays `nil` and requests carry the `_meta` envelope instead. - -### Server-to-Client Requests (Elicitation) - -Servers can send requests back to the client while one of the client's own requests is in flight - for example, -[`elicitation/create`](https://modelcontextprotocol.io/specification/2025-11-25/client/elicitation) to ask the user for additional input during a tool call. -Register a handler and advertise the capability on `connect` to respond to them: - -```ruby -client.connect(capabilities: { elicitation: {} }) - -client.on_elicitation do |params| - { - action: "accept", - # Fill fields omitted by the user with the schema's `default` values (SEP-1034) - content: MCP::Client::Elicitation.apply_defaults(params["requestedSchema"]), - } -end -``` - -Registering a handler opens a standalone HTTP GET SSE stream on a background thread -([listening for messages from the server](https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#listening-for-messages-from-the-server)), -since servers deliver requests that are not tied to a client request on that stream. Server requests with no registered handler are answered with -a JSON-RPC `-32601` (method not found) error. To handle methods other than `elicitation/create`, register directly on the transport with -`http_transport.on_server_request("method/name") { |params| ... }`. - -On a [modern](/client/lifecycle/) connection servers cannot send requests at all; the same -registered handlers instead drive the requests embedded in `input_required` results, -as documented on [Multi Round-Trip Requests](/client/mrtr/). - -### Server-to-Client Requests (Sampling) - -Servers can also request an LLM completion from the client with [`sampling/createMessage`](https://modelcontextprotocol.io/specification/2025-11-25/client/sampling), -letting a server leverage the client's model access without its own API keys. - -{: .warning } -> MCP Sampling is deprecated as of protocol version `2026-07-28` (SEP-2577), while remaining fully supported under `2025-11-25`. -> Register this handler to interoperate with servers that still send sampling requests during the deprecation window; -> new servers should call LLM provider APIs directly. - -Register a handler and advertise the capability on `connect`: - -```ruby -client.connect(capabilities: { sampling: {} }) - -client.on_sampling do |params| - completion = my_llm.complete(params["messages"], max_tokens: params["maxTokens"]) - { - role: "assistant", - content: { type: "text", text: completion.text }, - model: completion.model, - stopReason: "endTurn", - } -end -``` - -For trust and safety, the spec recommends a human in the loop able to review, edit, or reject the request and the generated response. -To reject a request, raise `MCP::Client::ServerRequestError` with the spec's user-rejection code `-1`: - -```ruby -client.on_sampling do |params| - raise MCP::Client::ServerRequestError.new("User rejected sampling request", code: -1) unless approved?(params) - - generate_completion(params) -end -``` - -Use `capabilities: { sampling: { tools: {} } }` to receive tool-enabled sampling requests. Like elicitation, this uses the same standalone GET SSE listening stream. - -### Custom Headers from Tool Parameters - -On a modern `MCP::Client::HTTP` connection, `tools/call` mirrors arguments whose `inputSchema` property carries -an `x-mcp-header` annotation into `Mcp-Param-{Name}` request headers per SEP-2243, so intermediaries can route -on the values without parsing bodies. The declarations are learned from `tools/list` responses: -list the tools before calling one to enable the mirroring. Values that cannot ride as plain ASCII header values -(non-ASCII, control characters, edge whitespace, empty strings) are wrapped as `=?base64?...?=`, -and a `null` or absent argument omits its header. - -Per the specification, a tool definition whose `x-mcp-header` annotations are invalid (empty or non-token names, -duplicate names, non-primitive properties, annotations outside a chain of `properties` keys) is excluded from -`tools/list` results on modern connections, with a warning naming the tool. -Legacy connections are unaffected: nothing is learned, mirrored, or excluded. - -### Customizing the Faraday Connection - -You can pass a block to `MCP::Client::HTTP.new` to customize the underlying Faraday connection. -The block is called after the default middleware is configured, so you can add middleware or swap the HTTP adapter: - -```ruby -http_transport = MCP::Client::HTTP.new(url: "https://api.example.com/mcp") do |faraday| - faraday.use MyApp::Middleware::HttpRecorder - faraday.adapter :typhoeus -end -``` - -The block customizes only the connection to the MCP server. The connection the OAuth flow uses for its own requests is customized through -the provider's `http_client_customizer:` keyword instead; see [Customizing the OAuth HTTP Client](/client/authorization/#customizing-the-oauth-http-client). - -{: .note } -> Answers to server-to-client requests (a pong, an elicitation result) are POSTed from inside -> the SSE streaming callback of another response, re-entering the connection on the same thread. -> The default Net::HTTP adapter opens a connection per request, which makes this safe; an adapter -> with persistent connections must tolerate that re-entry. - -## Custom Transports - -If the transport layer you need is not included in the gem, you can build and pass your own instances so long as they conform to the following interface: - -```ruby -class CustomTransport - # Sends a JSON-RPC request to the server and returns the raw response. - # - # @param request [Hash] A complete JSON-RPC request object. - # https://www.jsonrpc.org/specification#request_object - # @return [Hash] A hash modeling a JSON-RPC response object. - # https://www.jsonrpc.org/specification#response_object - def send_request(request:) - # Your transport-specific logic here - # - HTTP: POST to endpoint with JSON body - # - WebSocket: Send message over WebSocket - # - stdio: Write to stdout, read from stdin - # - etc. - end -end - -client = MCP::Client.new(transport: CustomTransport.new) -``` - -Custom transports that need to support client-side cancellation have additional requirements; -see [Custom transports](/client/cancellation/#custom-transports) on the Cancellation page. diff --git a/docs/_config.yml b/docs/_config.yml index 4f101a5..3b4ca1f 100644 --- a/docs/_config.yml +++ b/docs/_config.yml @@ -1,45 +1,6 @@ # Use package name as site title title: "MCP Ruby SDK" -description: "The official Ruby SDK for Model Context Protocol servers and clients." -remote_theme: just-the-docs/just-the-docs -color_scheme: ruby-light -plugins: - - jekyll-redirect-from - -# Sidebar sections: each collection renders as a plain category heading -# with its pages listed beneath it, instead of a clickable parent page. -collections: - server: - permalink: "/server/:name/" - output: true - client: - permalink: "/client/:name/" - output: true - extensions: - permalink: "/extensions/:name/" - output: true - -just_the_docs: - collections: - server: - name: Building Servers - client: - name: Building Clients - extensions: - name: Extensions - -# Search -search_enabled: true - -# Callouts -callouts: - note: - title: Note - color: blue - important: - title: Important - color: yellow - warning: - title: Warning - color: red +# Include generated files and directories which may start with underscores +include: + - "_*" diff --git a/docs/_extensions/capability-extensions.md b/docs/_extensions/capability-extensions.md deleted file mode 100644 index ba3f0c0..0000000 --- a/docs/_extensions/capability-extensions.md +++ /dev/null @@ -1,35 +0,0 @@ ---- -layout: default -title: Capability Extensions -nav_order: 2 ---- - -# Capability Extensions - -Per SEP-2133, both clients and servers can declare protocol extensions under the `extensions` member of their capabilities. -Keys are extension identifiers using the reverse-DNS prefix convention (e.g. `"io.modelcontextprotocol/tasks"`, `"com.example/feature"`); -values are extension-defined configuration objects, with `{}` meaning "supported with no settings". - -On the server, declare extensions through the `capabilities` keyword, either as a plain hash or via the `MCP::Server::Capabilities` builder: - -```ruby -capabilities = MCP::Server::Capabilities.new -capabilities.support_tools -capabilities.support_extensions("com.example/feature" => { enabled: true }) - -server = MCP::Server.new(name: "my_server", capabilities: capabilities) -``` - -The declared extensions appear in the `initialize` result's `capabilities.extensions`. Extensions the client declared during `initialize` are -readable via `server.client_capabilities[:extensions]` (or `session.client_capabilities[:extensions]` for per-session transports). - -On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle), the same declarations appear in the `server/discover` result, -and the client's extensions ride each request's `_meta` envelope instead of an `initialize` handshake. -Inside a handler, `server_context.client_capabilities[:extensions]` reads the current request's declarations -with envelope-first resolution, on either lifecycle. - -On the client, pass extensions through `connect`: - -```ruby -client.connect(capabilities: { extensions: { "com.example/feature" => {} } }) -``` diff --git a/docs/_extensions/index.md b/docs/_extensions/index.md deleted file mode 100644 index 5b52c0f..0000000 --- a/docs/_extensions/index.md +++ /dev/null @@ -1,17 +0,0 @@ ---- -layout: default -title: Overview -nav_order: 1 -permalink: /extensions/ ---- - -# Extensions - -Extensions add optional functionality on top of the core MCP protocol. -Support for an extension is negotiated per connection: -clients and servers declare the extensions they speak under the `extensions` member of their capabilities, -as described on [Capability Extensions](/extensions/capability-extensions/). - -The extensions this SDK ships support for: - -- [MCP Apps](/extensions/mcp-apps/) (SEP-1865) - interactive HTML user interfaces rendered by the host for tool results diff --git a/docs/_extensions/mcp-apps.md b/docs/_extensions/mcp-apps.md deleted file mode 100644 index 0c9c668..0000000 --- a/docs/_extensions/mcp-apps.md +++ /dev/null @@ -1,48 +0,0 @@ ---- -layout: default -title: MCP Apps -nav_order: 3 ---- - -# MCP Apps - -MCP Apps (SEP-1865) is a Final extension (negotiated via [Capability Extensions](/extensions/capability-extensions/)) that lets a server ship interactive -HTML user interfaces which the host renders for tool results. On the server side the extension is a thin convention, -and `MCP::Apps` provides the vocabulary and helpers: - -```ruby -capabilities = MCP::Server::Capabilities.new -capabilities.support_tools -capabilities.support_resources -capabilities.support_extensions(MCP::Apps.capability) # { "io.modelcontextprotocol/ui" => { mimeTypes: [...] } } - -server = MCP::Server.new( - name: "weather_server", - capabilities: capabilities, - # UI templates are ordinary resources with a `ui://` URI and the `text/html;profile=mcp-app` MIME type. - resources: [MCP::Apps.ui_resource(uri: "ui://weather-server/dashboard", name: "weather_dashboard")], -) - -server.resources_read_handler do |params| - [{ uri: params[:uri], mimeType: MCP::Apps::RESOURCE_MIME_TYPE, text: "..." }] -end - -# Link the tool to its template via `_meta.ui.resourceUri` (pass `legacy: true` to also -# emit the older flat `"ui/resourceUri"` alias for hosts that predate the Final spec). -server.define_tool( - name: "get_weather", - meta: MCP::Apps.tool_meta(resource_uri: "ui://weather-server/dashboard"), -) do |server_context:| - # The extension is optional: always return a meaningful text result, and use - # `MCP::Apps.client_supports?` when UI-capable clients should get richer structured content. - MCP::Apps.client_supports?(server_context.client_capabilities) # => true when the host declared the extension - MCP::Tool::Response.new([{ type: "text", text: "Sunny, 22 degrees Celsius" }]) -end -``` - -`MCP::Apps.tool_meta` also accepts `visibility:` (an array of `"model"` / `"app"`) to restrict who sees the tool, -and merges non-destructively into caller-supplied `meta:`. - -Everything else the extension defines (the sandboxed iframe, the `ui/*` `postMessage` bridge, consent for UI-initiated actions) -is the HOST's responsibility; a server only ever receives ordinary `resources/read` and `tools/call` requests. -See the [MCP Apps specification](https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx). diff --git a/docs/_includes/footer_custom.html b/docs/_includes/footer_custom.html deleted file mode 100644 index bfd1278..0000000 --- a/docs/_includes/footer_custom.html +++ /dev/null @@ -1,48 +0,0 @@ -{%- comment -%} - Previous/Next pager following the sidebar order: top-level pages by - nav_order, then the server, client, and extensions collections. -{%- endcomment -%} -{%- assign top_pages = site.html_pages | where_exp: "item", "item.nav_order" | sort: "nav_order" -%} -{%- assign server_docs = site.server | sort: "nav_order" -%} -{%- assign client_docs = site.client | sort: "nav_order" -%} -{%- assign extensions_docs = site.extensions | sort: "nav_order" -%} -{%- assign ordered_pages = top_pages | concat: server_docs | concat: client_docs | concat: extensions_docs -%} -{%- assign pager_state = "before" -%} -{%- assign prev_page = nil -%} -{%- assign next_page = nil -%} -{%- for item in ordered_pages -%} - {%- if pager_state == "current" -%} - {%- assign next_page = item -%} - {%- assign pager_state = "after" -%} - {%- elsif item.url == page.url -%} - {%- assign pager_state = "current" -%} - {%- elsif pager_state == "before" -%} - {%- assign prev_page = item -%} - {%- endif -%} -{%- endfor -%} -{%- if pager_state != "before" -%} - -{%- endif -%} diff --git a/docs/_includes/head_custom.html b/docs/_includes/head_custom.html deleted file mode 100644 index 34a88e6..0000000 --- a/docs/_includes/head_custom.html +++ /dev/null @@ -1,209 +0,0 @@ - - - - - diff --git a/docs/_includes/header_custom.html b/docs/_includes/header_custom.html deleted file mode 100644 index 8b2c640..0000000 --- a/docs/_includes/header_custom.html +++ /dev/null @@ -1,8 +0,0 @@ -
- - - - -
diff --git a/docs/_includes/nav_footer_custom.html b/docs/_includes/nav_footer_custom.html deleted file mode 100644 index f366cb0..0000000 --- a/docs/_includes/nav_footer_custom.html +++ /dev/null @@ -1,14 +0,0 @@ -{%- comment -%} - Replaces the theme's "This site uses Just the Docs" attribution, shown at - the bottom of the sidebar on desktop and in the page footer on mobile. - _data/versions.yml exists only on the deployed gh-pages tree, where - bin/generate-gh-pages.sh generates it; without it (local previews of - the docs/ source) only the license sentence renders. -{%- endcomment -%} -{% if site.data.versions %} -Documentation for mcp {{ site.data.versions | first }}, -licensed CC-BY-4.0. -{% else %} -Documentation licensed CC-BY-4.0. -{% endif %} -See LICENSE for the code. diff --git a/docs/_preview/taint_shim.rb b/docs/_preview/taint_shim.rb deleted file mode 100644 index 9d43470..0000000 --- a/docs/_preview/taint_shim.rb +++ /dev/null @@ -1,18 +0,0 @@ -# frozen_string_literal: true - -# Liquid 4.0.3 (pinned by github-pages) still calls the taint API that Ruby 3.2 removed. -# Restore it as a no-op for the local docs preview only; `rake docs:preview` loads -# this file via `RUBYOPT`, so nothing outside the preview process is affected. -class Object - def tainted? - false - end - - def taint - self - end - - def untaint - self - end -end diff --git a/docs/_sass/color_schemes/ruby-dark.scss b/docs/_sass/color_schemes/ruby-dark.scss deleted file mode 100644 index 5bd0ef1..0000000 --- a/docs/_sass/color_schemes/ruby-dark.scss +++ /dev/null @@ -1,17 +0,0 @@ -// Dark counterpart of ruby-light: the link color is lightened from -// the #b61d1d accent so it keeps WCAG AA contrast, and the theme's -// purple-tinted dark greys become neutral ones. -@import "./color_schemes/dark"; - -$link-color: #f0776c; -$btn-primary-color: #b61d1d; - -// The dark scheme derives $feedback-color before these overrides apply, -// so it is restated. -$body-background-color: #252525; -$sidebar-color: #252525; -$feedback-color: #1e1e1e; -$search-background-color: #202020; -$table-background-color: #202020; -$base-button-color: #202020; -$border-color: #3f3f3f; diff --git a/docs/_sass/color_schemes/ruby-light.scss b/docs/_sass/color_schemes/ruby-light.scss deleted file mode 100644 index 5da81c3..0000000 --- a/docs/_sass/color_schemes/ruby-light.scss +++ /dev/null @@ -1,8 +0,0 @@ -// The include imports the light scheme first, so only overrides live here. -$link-color: #990000; -$btn-primary-color: #b61d1d; -$sidebar-color: #fff; - -// The light scheme derives $feedback-color before these overrides apply, -// so it is restated (the hover shade on the white sidebar). -$feedback-color: #f2f2f2; diff --git a/docs/_sass/custom/custom.scss b/docs/_sass/custom/custom.scss deleted file mode 100644 index 7f89847..0000000 --- a/docs/_sass/custom/custom.scss +++ /dev/null @@ -1,149 +0,0 @@ -.docs-header-controls { - display: flex; - height: 3.75rem; - align-items: stretch; - justify-content: flex-end; - margin-left: auto; -} - -@media (min-width: 50rem) { - .docs-header-controls { - height: 100%; - padding-right: 1rem; - } -} - -.docs-icon-button.site-button { - width: 3.75rem; - justify-content: center; - padding: 0; - color: inherit; - background-color: transparent; - border: 0; - cursor: pointer; - font: inherit; - text-decoration: none; -} - -.docs-icon { - display: block; - width: 1.25rem; - height: 1.25rem; - background-color: currentColor; - -webkit-mask-position: center; - -webkit-mask-repeat: no-repeat; - -webkit-mask-size: contain; - mask-position: center; - mask-repeat: no-repeat; - mask-size: contain; -} - -.docs-icon--github { - -webkit-mask-image: url("/assets/images/icons/github.svg"); - mask-image: url("/assets/images/icons/github.svg"); -} - -.docs-icon--theme { - -webkit-mask-image: url("/assets/images/icons/theme-system.svg"); - mask-image: url("/assets/images/icons/theme-system.svg"); -} - -:root[data-theme-preference="light"] .docs-icon--theme { - -webkit-mask-image: url("/assets/images/icons/theme-light.svg"); - mask-image: url("/assets/images/icons/theme-light.svg"); -} - -:root[data-theme-preference="dark"] .docs-icon--theme { - -webkit-mask-image: url("/assets/images/icons/theme-dark.svg"); - mask-image: url("/assets/images/icons/theme-dark.svg"); -} - -:root[data-theme="dark"] { - color-scheme: dark; -} - -/* - * Applied before the dark stylesheet finishes loading, so browsers that - * do not support blocking="render" avoid a light-colored first paint. - * Values match $body-background-color from the ruby-dark color scheme - * and $grey-lt-300 for the text. - */ -:root[data-theme="dark"] body { - background-color: #252525; - color: #e6e1e8; -} - -:root[data-theme="light"] { - color-scheme: light; -} - -/* - * Center the sidebar-plus-content block as one unit, splitting the leftover viewport equally - * on both sides. The theme instead widens the sidebar to absorb the whole left overflow, - * and its margin rule lives on `.side-bar + .main`, which a bare `.main` selector cannot override. - */ -$docs-content-width: 64rem; - -@media (min-width: 66.5rem) { - .side-bar { - /* Capitalized Max/Min pass through the Sass compiler as plain CSS. */ - left: Max(0px, calc((100% - #{$nav-width + $docs-content-width}) / 2)); - width: $nav-width; - } - - .side-bar + .main { - max-width: $docs-content-width; - margin-left: Max(#{$nav-width}, calc((100% - #{$nav-width + $docs-content-width}) / 2 + #{$nav-width})); - } - - /* Breathing room between the sidebar and the content. */ - .main-content-wrap { - padding-left: 3rem; - } - - .main-header { - padding-left: 1rem; - } -} - -/* Previous/Next pager in the page footer. */ -.docs-pager { - display: flex; - gap: 1rem; - justify-content: space-between; -} - -.docs-pager-link { - display: flex; - flex-direction: column; - max-width: 48%; - text-decoration: none; -} - -.docs-pager-next { - margin-left: auto; - text-align: right; -} - -.docs-pager-direction { - font-size: 0.6875rem; - text-transform: uppercase; - letter-spacing: 0.08em; - color: $body-text-color; - opacity: 0.6; -} - -.docs-pager-title { - font-weight: 600; -} - -/* - * Category headings read as section labels, not separators: no underline, - * spaced apart from the preceding group and letter-spaced instead. - */ -.nav-category { - margin-top: 1.5rem; - letter-spacing: 0.08em; - border-bottom: none; - opacity: 0.65; -} diff --git a/docs/_sass/custom/setup.scss b/docs/_sass/custom/setup.scss deleted file mode 100644 index b34691c..0000000 --- a/docs/_sass/custom/setup.scss +++ /dev/null @@ -1,2 +0,0 @@ -// Widen the sidebar from the theme's 16.5rem default. -$nav-width: 19rem; diff --git a/docs/_server/cancellation.md b/docs/_server/cancellation.md deleted file mode 100644 index 1bc0b17..0000000 --- a/docs/_server/cancellation.md +++ /dev/null @@ -1,137 +0,0 @@ ---- -layout: default -title: Cancellation -nav_order: 13 ---- - -# Cancellation - -The MCP Ruby SDK supports server-side handling of -the [MCP `notifications/cancelled` utility](https://modelcontextprotocol.io/specification/latest/basic/patterns/cancellation). -When a client sends `notifications/cancelled` for an in-flight request, the server stops -processing cooperatively and suppresses the JSON-RPC response for that request. - -Cancellation is cooperative: the SDK does not forcibly terminate tool code. Instead, -a `MCP::Cancellation` token is threaded through [`server_context`](/server/server-context/), and long-running tools -poll it to exit early. When a tool returns after cancellation has been observed, -the server suppresses the JSON-RPC response, matching the spec. The `initialize` request -is never cancellable per the spec. - -{: .note } -> Cancellation by notification belongs to the handshake lifecycle, where the session correlates -> `notifications/cancelled` with the in-flight request it targets. Requests of the -> [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) are sessionless single POST exchanges, so a separately -> POSTed cancel notification cannot reach them; a modern client abandons a request by closing -> the connection instead. - -## Handlers that Check for Cancellation - -Any handler that opts in to `server_context:` - tools (`Tool.call`), prompt templates, -`resources_read_handler`, `resources_list_handler`, `completion_handler`, `resources_subscribe_handler`, -`resources_unsubscribe_handler`, and [`define_custom_method`](/server/custom-methods/) blocks - receives -an `MCP::ServerContext` wired to the in-flight request's cancellation token. -Handlers check `cancelled?` in their work loop, or call `raise_if_cancelled!` to raise -`MCP::CancelledError` at a safe point: - -```ruby -class LongRunningTool < MCP::Tool - description "A tool that supports cancellation" - input_schema(properties: { count: { type: "integer" } }, required: ["count"]) - - def self.call(count:, server_context:) - count.times do |i| - # Exit early if the client has sent `notifications/cancelled`. - break if server_context.cancelled? - - do_work(i) - end - - MCP::Tool::Response.new([{ type: "text", text: "Done" }]) - end -end -``` - -Alternatively, raise at the next safe point with `raise_if_cancelled!`: - -```ruby -def self.call(count:, server_context:) - count.times do |i| - server_context.raise_if_cancelled! - - do_work(i) - end - - MCP::Tool::Response.new([{ type: "text", text: "Done" }]) -end -``` - -When a handler observes cancellation (either by returning early with `cancelled?` or -by raising `MCP::CancelledError` via `raise_if_cancelled!`), the server drops the response and -no JSON-RPC result is sent to the client. - -The same pattern works for other handler types: - -```ruby -# resources/read -server.resources_read_handler do |params, server_context:| - server_context.raise_if_cancelled! - # read the resource -end - -# completion/complete -server.completion_handler do |params, server_context:| - server_context.raise_if_cancelled! - # compute completions -end - -# custom method -server.define_custom_method(method_name: "custom/slow") do |params, server_context:| - server_context.raise_if_cancelled! - # do work -end - -# prompts (via Prompt subclass) -class SlowPrompt < MCP::Prompt - prompt_name "slow_prompt" - - def self.template(args, server_context:) - server_context.raise_if_cancelled! - MCP::Prompt::Result.new(messages: []) - end -end -``` - -Handlers that do not declare a `server_context:` keyword continue to work unchanged - -the opt-in detection only wraps the context when the block signature asks for it. - -## Nested Server-to-Client Requests Are Cancelled Automatically - -When a tool handler is waiting on a nested server-to-client request -(`server_context.create_sampling_message`, `create_form_elicitation`, or -`create_url_elicitation`), cancelling the parent tool call automatically raises -`MCP::CancelledError` from the nested call, so the tool does not need to wrap it -in its own `cancelled?` checks: - -```ruby -def self.call(server_context:) - result = server_context.create_sampling_message(messages: messages, max_tokens: 100) - # If the parent tools/call is cancelled while waiting above, MCP::CancelledError - # is raised here and the tool can let it propagate or clean up as needed. - MCP::Tool::Response.new([{ type: "text", text: result[:content][:text] }]) -rescue MCP::CancelledError - # Optional: run cleanup. Re-raising (or letting it propagate) is fine; the server - # will still suppress the JSON-RPC response per the MCP spec. - raise -end -``` - -Nested cancellation propagation is supported on `StreamableHTTPTransport` only. -`StdioTransport` is single-threaded and blocks on `$stdin.gets`, so a nested -`server_context.create_sampling_message` inside a tool runs to completion even if -the parent `tools/call` is cancelled. The parent tool itself still observes cancellation -via `server_context.cancelled?` between nested calls. - -## Client Side - -Cancelling a request the client has issued (the `cancellation:` keyword, wire-order guarantees, -and custom transport requirements) is documented on the client [Cancellation](/client/cancellation/) page. diff --git a/docs/_server/completion.md b/docs/_server/completion.md deleted file mode 100644 index 583a4bc..0000000 --- a/docs/_server/completion.md +++ /dev/null @@ -1,54 +0,0 @@ ---- -layout: default -title: Completion -nav_order: 16 -redirect_from: - - /server/completions/ ---- - -# Completion - -MCP spec includes [Completions](https://modelcontextprotocol.io/specification/latest/server/utilities/completion), -which enable servers to provide autocompletion suggestions for prompt arguments and resource URIs. - -To enable completions, declare the `completions` capability and register a handler: - -```ruby -server = MCP::Server.new( - name: "my_server", - prompts: [CodeReviewPrompt], - resource_templates: [FileTemplate], - capabilities: { completions: {} }, -) - -server.completion_handler do |params| - ref = params[:ref] - argument = params[:argument] - value = argument[:value] - - case ref[:type] - when "ref/prompt" - values = case argument[:name] - when "language" - ["python", "pytorch", "pyside"].select { |v| v.start_with?(value) } - else - [] - end - { completion: { values: values, hasMore: false } } - when "ref/resource" - { completion: { values: [], hasMore: false } } - end -end -``` - -The handler receives a `params` hash with: - -- `ref` - The reference (`{ type: "ref/prompt", name: "..." }` or `{ type: "ref/resource", uri: "..." }`) -- `argument` - The argument being completed (`{ name: "...", value: "..." }`) -- `context` (optional) - Previously resolved arguments (`{ arguments: { ... } }`) - -The handler must return a hash with a `completion` key containing `values` (array of strings), and optionally `total` and `hasMore`. -The SDK automatically enforces the 100-item limit per the MCP specification. - -The server validates that the referenced prompt, resource, or resource template is registered before calling the handler. -Requests for unknown references return an error. diff --git a/docs/_server/configuration.md b/docs/_server/configuration.md deleted file mode 100644 index 9480df8..0000000 --- a/docs/_server/configuration.md +++ /dev/null @@ -1,206 +0,0 @@ ---- -layout: default -title: Configuration -nav_order: 20 ---- - -# Configuration - -The gem can be configured using the `MCP.configure` block: - -```ruby -MCP.configure do |config| - config.exception_reporter = ->(exception, server_context) { - # Your exception reporting logic here - # For example with Bugsnag: - Bugsnag.notify(exception) do |report| - report.add_metadata(:model_context_protocol, server_context) - end - } - - config.around_request = ->(data, &request_handler) { - logger.info("Start: #{data[:method]}") - request_handler.call - logger.info("Done: #{data[:method]}, tool: #{data[:tool_name]}") - } -end -``` - -or by creating an explicit configuration and passing it into the server. -This is useful for systems where an application hosts more than one MCP server but -they might require different configurations. - -```ruby -configuration = MCP::Configuration.new -configuration.exception_reporter = ->(exception, server_context) { - # Your exception reporting logic here - # For example with Bugsnag: - Bugsnag.notify(exception) do |report| - report.add_metadata(:model_context_protocol, server_context) - end -} - -configuration.around_request = ->(data, &request_handler) { - logger.info("Start: #{data[:method]}") - request_handler.call - logger.info("Done: #{data[:method]}, tool: #{data[:tool_name]}") -} - -server = MCP::Server.new( - # ... all other options - configuration:, -) -``` - -## Exception Reporter - -The exception reporter receives two arguments: - -- `exception`: The Ruby exception object that was raised -- `server_context`: A hash containing contextual information about where the error occurred. - This is not the user-defined [`server_context`](/server/server-context/) passed to `Server.new`. - -The `server_context` hash includes: - -- For request handling failures: `{ request: { ... } }` (the raw JSON-RPC request hash) -- For notification delivery failures: `{ notification: "tools_list_changed" }` (or the relevant notification name) - -**Signature:** - -```ruby -exception_reporter = ->(exception, server_context) { ... } -``` - -When an exception occurs: - -1. The exception is reported via the configured reporter -2. The client receives a generic JSON-RPC error response (for example, "Internal error calling tool " - for a tool call); the exception's own message is deliberately withheld from clients - -If no exception reporter is configured, a default no-op reporter is used that silently ignores exceptions. - -## Around Request - -The `around_request` hook wraps request handling, allowing you to execute code before and after each request. -This is useful for Application Performance Monitoring (APM) tracing, logging, or other observability needs. - -The hook receives a `data` hash and a `request_handler` block. You must call `request_handler.call` to execute the request: - -**Signature:** - -```ruby -around_request = ->(data, &request_handler) { request_handler.call } -``` - -**`data` availability by timing:** - -- Before `request_handler.call`: `method`, and `server_context` when `instrument_server_context` is enabled -- After `request_handler.call`: `tool_name`, `tool_arguments`, `prompt_name`, `resource_uri`, `error`, `client` -- Not available inside `around_request`: `duration` (added after `around_request` returns) - -{: .note } -> `tool_name`, `prompt_name` and `resource_uri` may only be populated for the corresponding request methods -> (`tools/call`, `prompts/get`, `resources/read`), and may not be set depending on how the request is handled -> (for example, `prompt_name` is not recorded when the prompt is not found). -> `duration` is added after `around_request` returns, so it is not visible from within the hook. - -**Example:** - -```ruby -MCP.configure do |config| - config.around_request = ->(data, &request_handler) { - logger.info("Start: #{data[:method]}") - request_handler.call - logger.info("Done: #{data[:method]}, tool: #{data[:tool_name]}") - } -end -``` - -### Exposing the User-Defined `server_context` - -`data` omits the user-defined `server_context` by default, because that hash is -application-supplied and may hold values a tracing backend should not receive. -Enable it when you need to tag spans with the request's subject: - -```ruby -MCP.configure do |config| - config.instrument_server_context = true - - config.around_request = ->(data, &request_handler) { - Sentry.set_user(id: data.dig(:server_context, :user_id)) - request_handler.call - } -end -``` - -`data[:server_context]` is the hash passed to `Server.new` - `nil` when the host -set none. It is not the exception reporter's context argument, which describes -where a failure occurred rather than who made the request. - -## Instrumentation Callback (soft-deprecated) - -{: .note } -> `instrumentation_callback` is soft-deprecated. Use `around_request` instead. -> -> To migrate, wrap the call in `begin/ensure` so the callback still runs when the request fails: -> -> ```ruby -> # Before -> config.instrumentation_callback = ->(data) { log(data) } -> -> # After -> config.around_request = ->(data, &request_handler) do -> request_handler.call -> ensure -> log(data) -> end -> ``` -> -> Note that `data[:duration]` is not available inside `around_request`. -> If you need it, measure elapsed time yourself within the hook, or keep using `instrumentation_callback`. - -The instrumentation callback is called after each request finishes, whether successfully or with an error. -It receives a hash with the following possible keys: - -- `method`: (String) The protocol method called (e.g., "ping", "tools/list") -- `tool_name`: (String, optional) The name of the tool called -- `tool_arguments`: (Hash, optional) The arguments passed to the tool -- `prompt_name`: (String, optional) The name of the prompt called -- `resource_uri`: (String, optional) The URI of the resource called -- `error`: (String, optional) Error code if a lookup failed -- `duration`: (Float) Duration of the call in seconds -- `client`: (Hash, optional) Client information with `name` and `version` keys, from the initialize request -- `server_context`: (Any, optional) The user-defined hash passed to `Server.new`, present only when - `instrument_server_context` is enabled - -**Signature:** - -```ruby -instrumentation_callback = ->(data) { ... } -``` - -## Server Protocol Version - -The server's protocol version can be overridden using the `protocol_version` keyword argument: - -```ruby -configuration = MCP::Configuration.new(protocol_version: "2024-11-05") -MCP::Server.new(name: "test_server", configuration: configuration) -``` - -If no protocol version is specified, the latest handshake version (`2025-11-25`) is applied by default. - -This will make all new server instances use the specified protocol version instead of the default version. The protocol version can be reset to the default by setting it to `nil`: - -```ruby -MCP::Configuration.new(protocol_version: nil) -``` - -If an invalid `protocol_version` value is set, an `ArgumentError` is raised. - -The pin scopes the `initialize` handshake, so it accepts handshake versions (`2025-11-25` and earlier) only. Per the SEP-2575 era model, -`2026-07-28` carries its version on every request and has no handshake at all, so there is nothing for a pin to configure there and setting it raises `ArgumentError`; -a client asking `initialize` for a modern version is counter-offered the pinned version (or the latest handshake version), matching the TypeScript and Python SDKs. -Clients reach `2026-07-28` through [`server/discover`](/server/discover/) and the per-request `_meta` envelope, which the bundled transports serve alongside the handshake with no configuration needed. - -Be sure to check the [MCP spec](https://modelcontextprotocol.io/specification/versioning) for the protocol version to understand the supported features for the version being set. diff --git a/docs/_server/custom-methods.md b/docs/_server/custom-methods.md deleted file mode 100644 index 85dc87a..0000000 --- a/docs/_server/custom-methods.md +++ /dev/null @@ -1,62 +0,0 @@ ---- -layout: default -title: Custom Methods -nav_order: 21 ---- - -# Custom Methods - -The server allows you to define custom JSON-RPC methods beyond the standard MCP protocol methods using the `define_custom_method` method: - -```ruby -server = MCP::Server.new(name: "my_server") - -# Define a custom method that returns a result -server.define_custom_method(method_name: "add") do |params| - params[:a] + params[:b] -end - -# Define a custom notification method (returns nil) -server.define_custom_method(method_name: "notify") do |params| - # Process notification - nil -end -``` - -**Key Features:** - -- Accepts any method name as a string -- Block receives the request parameters as a hash -- Can handle both regular methods (with responses) and notifications -- Prevents overriding existing MCP protocol methods -- Supports instrumentation callbacks for monitoring -- Blocks may opt in to a [`server_context:`](/server/server-context/) keyword like the built-in handlers - (see [Cancellation](/server/cancellation/) for an example) - -**Usage Example:** - -The wire exchange for the custom `add` method defined above. The client sends: - -```json -{ - "jsonrpc": "2.0", - "id": 1, - "method": "add", - "params": { "a": 5, "b": 3 } -} -``` - -The server responds: - -```json -{ - "jsonrpc": "2.0", - "id": 1, - "result": 8 -} -``` - -**Error Handling:** - -- Raises `MCP::Server::MethodAlreadyDefinedError` if trying to override an existing method -- Supports the same [exception reporting and instrumentation](/server/configuration/) as standard methods diff --git a/docs/_server/discover.md b/docs/_server/discover.md deleted file mode 100644 index 20f8bd6..0000000 --- a/docs/_server/discover.md +++ /dev/null @@ -1,63 +0,0 @@ ---- -layout: default -title: Discovery -nav_order: 3 -redirect_from: - - /server/discovery/ ---- - -# Discovery - -`server/discover` is the sessionless capability discovery method of MCP 2026-07-28 (SEP-2575). -It responds before `initialize` and without an `Mcp-Session-Id`, so a client learns what a server -offers in a single exchange, without creating a session. - -## The Discovery Result - -The result carries the modern `supportedVersions`, `capabilities`, and `instructions`, together with -the required `ttlMs`/`cacheScope` cache hints, and the server identity as the optional -`io.modelcontextprotocol/serverInfo` stamp in the result `_meta`. - -The request takes no parameters: - -```json -{ "jsonrpc": "2.0", "id": 1, "method": "server/discover" } -``` - -The server answers with the full discovery result: - -```json -{ - "jsonrpc": "2.0", - "id": 1, - "result": { - "supportedVersions": ["2026-07-28"], - "capabilities": { "tools": { "listChanged": true } }, - "instructions": "Use the tools of this server as a last resort", - "_meta": { "io.modelcontextprotocol/serverInfo": { "name": "my_server", "version": "1.0.0" } }, - "ttlMs": 0, - "cacheScope": "private", - "resultType": "complete" - } -} -``` - -## The Stateless Modern Lifecycle - -Beyond answering `server/discover`, the server serves the full stateless modern lifecycle: requests carrying the SEP-2575 `_meta` envelope -(`io.modelcontextprotocol/protocolVersion`, `clientInfo`, and `clientCapabilities`) are validated per request, -and the Streamable HTTP transport serves them on a sessionless single-exchange path. -Calling `server/discover` first is not required: the envelope alone selects the modern lifecycle for a request, -while a client performing the classic `initialize` handshake is served on the handshake lifecycle - -the lifecycle is a per-request property, not a server-wide mode. - -The bundled transports serve `server/discover` and the per-request `_meta` envelope alongside the `initialize` handshake -with no configuration needed. The `protocol_version` pin scopes the handshake only -and does not affect the modern lifecycle; see [Configuration](/server/configuration/) for details. - -## Client Side - -On the client, `MCP::Client#connect` negotiates the lifecycle automatically by default -(probe `server/discover`, fall back to the `initialize` handshake), `connect(mode: :modern)` skips -the handshake entirely, `connect(mode: :legacy)` forces the classic handshake, and `MCP::Client#discover` -exposes the raw discovery result. See the client-side [Lifecycle](/client/lifecycle/) page for details. diff --git a/docs/_server/elicitation.md b/docs/_server/elicitation.md deleted file mode 100644 index 4eea52b..0000000 --- a/docs/_server/elicitation.md +++ /dev/null @@ -1,231 +0,0 @@ ---- -layout: default -title: Elicitation -nav_order: 9 ---- - -# Elicitation - -The MCP Ruby SDK supports [elicitation](https://modelcontextprotocol.io/specification/latest/client/elicitation), -which allows servers to request additional information from users through the client during tool execution. - -Elicitation is a **server-to-client request**. The server sends a request and blocks until the user responds via the client. - -{: .note } -> Unlike [roots](/server/roots/) and [sampling](/server/sampling/), elicitation carries no SEP-2577 deprecation -> and remains fully available. On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) (MCP 2026-07-28), which forbids server-initiated requests, -> an `elicitation/create` request is embedded in an `input_required` result instead; -> see [Multi Round-Trip Requests](/server/mrtr/). - -{: .important } -> Per SEP-2260, server-to-client requests (`roots/list`, `sampling/createMessage`, `elicitation/create`) must be associated with -> an originating client request (`ping` is exempt). Use the `server_context` passed to your handler, which stamps the association -> automatically and routes the request onto the originating POST stream on the Streamable HTTP transport. Calling the corresponding -> `ServerSession` methods without `related_request_id:` still works but emits a deprecation warning. - -## Capabilities - -Clients must declare the `elicitation` capability during initialization. The server checks this before sending any elicitation request -and raises a `RuntimeError` if the client does not support it. - -For URL mode support, the client must also declare `elicitation.url` capability. - -## Using Elicitation in Tools - -Tools that accept a [`server_context:`](/server/server-context/) parameter can call `create_form_elicitation` on it: - -```ruby -server.define_tool(name: "collect_info", description: "Collect user info") do |server_context:| - result = server_context.create_form_elicitation( - message: "Please provide your name", - requested_schema: { - type: "object", - properties: { name: { type: "string" } }, - required: ["name"], - }, - ) - - MCP::Tool::Response.new([{ type: "text", text: "Hello, #{result[:content][:name]}" }]) -end -``` - -## Form Mode - -Form mode collects structured data from the user directly through the MCP client: - -```ruby -server.define_tool(name: "collect_contact", description: "Collect contact info") do |server_context:| - result = server_context.create_form_elicitation( - message: "Please provide your contact information", - requested_schema: { - type: "object", - properties: { - name: { type: "string", description: "Your full name" }, - email: { type: "string", format: "email", description: "Your email address" }, - }, - required: ["name", "email"], - }, - ) - - text = case result[:action] - when "accept" - "Hello, #{result[:content][:name]} (#{result[:content][:email]})" - when "decline" - "User declined" - when "cancel" - "User cancelled" - end - - MCP::Tool::Response.new([{ type: "text", text: text }]) -end -``` - -The `requested_schema` must be a flat object schema: a top-level `type: "object"` whose `properties` are limited to -primitive types (`string`, `number`, `integer`, `boolean`). Nested objects and arrays are not allowed, which keeps -the schema simple enough for clients to render as a form. Per the MCP specification, the client validates -the user's input against this schema before returning it, so the `content` of an `accept` response matches the requested shape. - -## Default Values and Enums - -Properties may declare a `default` value (SEP-1034), which clients use to pre-fill the form. -String properties may declare `enum` values, optionally with human-readable `enumNames` (SEP-1330), which clients render as a choice list: - -```ruby -server.define_tool(name: "configure_deploy", description: "Configure a deployment") do |server_context:| - result = server_context.create_form_elicitation( - message: "Configure the deployment", - requested_schema: { - type: "object", - properties: { - replicas: { type: "integer", default: 3 }, - verbose: { type: "boolean", default: false }, - environment: { - type: "string", - enum: ["dev", "staging", "prod"], - enumNames: ["Development", "Staging", "Production"], - default: "dev", - }, - }, - required: ["environment"], - }, - ) - - MCP::Tool::Response.new([{ type: "text", text: "Deploying to #{result[:content][:environment]}" }]) -end -``` - -## Enum Schemas - -For enumerated choices, use `MCP::Elicitation::EnumSchema` to construct the canonical schema shapes per -[SEP-1330](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1330) instead of building -the underlying Hash by hand. The five class methods cover titled and untitled, single-select and multi-select, -plus the legacy `enumNames` form retained for backward compatibility: - -```ruby -size_schema = MCP::Elicitation::EnumSchema.titled_single_select( - options: [ - { value: "s", title: "Small" }, - { value: "m", title: "Medium" }, - { value: "l", title: "Large" }, - ], - default: "m", -) - -tags_schema = MCP::Elicitation::EnumSchema.untitled_multi_select( - values: ["urgent", "billing", "feedback"], -) - -result = server_context.create_form_elicitation( - message: "Tell us about your order", - requested_schema: { - type: "object", - properties: { - size: size_schema.to_h, - tags: tags_schema.to_h, - }, - required: ["size"], - }, -) -``` - -The available builders are `untitled_single_select`, `titled_single_select`, `untitled_multi_select`, `titled_multi_select`, -and `legacy_titled`. Each accepts optional `default:`, `title:`, and `description:`. - -The same builders produce the `requestedSchema` of an `elicitation/create` request embedded in a SEP-2322 `input_required` result, -which is how elicitation reaches clients on the stateless 2026-07-28 lifecycle: - -```ruby -MCP::Server::InputRequiredResult.new( - input_requests: { - "size" => { - method: "elicitation/create", - params: { - message: "Pick a size", - requestedSchema: { - type: "object", - properties: { size: size_schema.to_h }, - required: ["size"], - }, - }, - }, - }, -) -``` - -## URL Mode - -URL mode directs the user to an external URL for out-of-band interactions such as OAuth flows: - -```ruby -server.define_tool(name: "authorize_github", description: "Authorize GitHub") do |server_context:| - elicitation_id = SecureRandom.uuid - - result = server_context.create_url_elicitation( - message: "Please authorize access to your GitHub account", - url: "https://example.com/oauth/authorize?elicitation_id=#{elicitation_id}", - elicitation_id: elicitation_id, - ) - - server_context.notify_elicitation_complete(elicitation_id: elicitation_id) - - MCP::Tool::Response.new([{ type: "text", text: "Authorization complete" }]) -end -``` - -## URLElicitationRequiredError - -When a tool cannot proceed until an out-of-band elicitation is completed, raise `MCP::Server::URLElicitationRequiredError`. -This returns a JSON-RPC error with code `-32042` to the client: - -```ruby -server.define_tool(name: "access_github", description: "Access GitHub") do |server_context:| - raise MCP::Server::URLElicitationRequiredError.new([ - { - mode: "url", - elicitationId: SecureRandom.uuid, - url: "https://example.com/oauth/authorize", - message: "GitHub authorization is required.", - }, - ]) -end -``` - -## Timeouts - -Every server-to-client request is bounded, so a client that never answers cannot park the handler's thread indefinitely. -`MCP::Server::Transports::StreamableHTTPTransport` waits `server_to_client_request_timeout:` seconds (600 by default), then tells -the client the request was abandoned and raises `MCP::Server::RequestTimeoutError`. Individual calls override the deadline with `timeout:`, -which is the knob to reach for when a prompt legitimately waits on a person: - -```ruby -server_context.create_form_elicitation( - message: "Approve this deployment?", - requested_schema: { type: "object", properties: { approved: { type: "boolean" } } }, - timeout: 3600, # This one waits up to an hour. -) -``` - -`StdioTransport` is not bounded and ignores `timeout:`: it owns the client process, so a client that stops answering -surfaces as end-of-file rather than as a wait that never ends. - -The same timeout applies to [roots](/server/roots/) and [sampling](/server/sampling/) requests. diff --git a/docs/_server/index.md b/docs/_server/index.md deleted file mode 100644 index 5d938f1..0000000 --- a/docs/_server/index.md +++ /dev/null @@ -1,53 +0,0 @@ ---- -layout: default -title: Overview -nav_order: 1 -permalink: /server/ -redirect_from: - - /building-servers.html - - /building-servers/ ---- - -# Building an MCP Server - -The `MCP::Server` class is the core component that handles JSON-RPC requests and responses. -It implements the Model Context Protocol specification, handling model context requests and responses. - -## Key Features - -- Implements JSON-RPC 2.0 message handling -- Supports protocol initialization and capability negotiation -- Manages tool registration and invocation -- Supports prompt registration and execution -- Supports resource registration and retrieval -- Supports stdio and Streamable HTTP (including SSE) transports -- Supports notifications for list changes (tools, prompts, resources) -- Supports roots (server-to-client filesystem boundary queries; deprecated as of 2026-07-28) -- Supports sampling (server-to-client LLM completion requests; deprecated as of 2026-07-28) -- Supports cursor-based pagination for list operations -- Supports cancellation of in-flight requests on both server and client (notifications/cancelled) - -## Supported Methods - -- `initialize` - Initializes the protocol and returns server capabilities -- `server/discover` - Sessionless capability discovery (MCP 2026-07-28, SEP-2575): returns the server's capabilities - before `initialize` and without an `Mcp-Session-Id`, and anchors the stateless modern lifecycle; see [Discovery](/server/discover/) -- `subscriptions/listen` - Long-lived notification subscription stream (MCP 2026-07-28, SEP-2575), replacing the legacy HTTP GET - listening stream; see [Subscriptions](/server/subscriptions/) -- Multi round-trip `input_required` results (MCP 2026-07-28, SEP-2322): handlers return `MCP::Server::InputRequiredResult` to ask - the client for additional input instead of performing a server-initiated request; see [Multi Round-Trip Requests](/server/mrtr/) -- `ping` - Simple health check -- `logging/setLevel` - Configures the minimum log level for the server (deprecated as of 2026-07-28) -- `tools/list` - Lists all registered tools and their schemas -- `tools/call` - Invokes a specific tool with provided arguments -- `prompts/list` - Lists all registered prompts and their schemas -- `prompts/get` - Retrieves a specific prompt by name -- `resources/list` - Lists all registered resources and their schemas -- `resources/read` - Retrieves a specific resource by name -- `resources/templates/list` - Lists all registered resource templates and their schemas -- `resources/subscribe` - Subscribes to updates for a specific resource -- `resources/unsubscribe` - Unsubscribes from updates for a specific resource -- `completion/complete` - Returns autocompletion suggestions for prompt arguments and resource URIs -- `roots/list` - Requests filesystem roots from the client (server-to-client; deprecated as of 2026-07-28) -- `sampling/createMessage` - Requests LLM completion from the client (server-to-client; deprecated as of 2026-07-28) -- `elicitation/create` - Requests user input from the client (server-to-client) diff --git a/docs/_server/logging.md b/docs/_server/logging.md deleted file mode 100644 index b861628..0000000 --- a/docs/_server/logging.md +++ /dev/null @@ -1,90 +0,0 @@ ---- -layout: default -title: Logging -nav_order: 17 ---- - -# Logging - -The MCP Ruby SDK supports structured logging through the `notify_log_message` method, following the [MCP Logging specification](https://modelcontextprotocol.io/specification/latest/server/utilities/logging). - -The `notifications/message` notification is used for structured logging between client and server. - -{: .warning } -> MCP Logging (`logging/setLevel` and `notifications/message`) is deprecated as of protocol version `2026-07-28` (SEP-2577), -> while remaining fully supported under `2025-11-25`. Use stderr or OpenTelemetry for new servers. - -{: .note } -> On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle), where `logging/setLevel` does not exist, the level -> comes per request from the `io.modelcontextprotocol/logLevel` `_meta` member: it authorizes -> `notifications/message` for that request only, delivered on the request's own response stream. -> A request without the member (or with an unrecognized level) receives no log messages. - -## Log Levels - -The SDK supports 8 log levels with increasing severity: - -- `debug` - Detailed debugging information -- `info` - General informational messages -- `notice` - Normal but significant events -- `warning` - Warning conditions -- `error` - Error conditions -- `critical` - Critical conditions -- `alert` - Action must be taken immediately -- `emergency` - System is unusable - -## How Logging Works - -1. **Client Configuration**: The client sends a `logging/setLevel` request to configure the minimum log level -2. **Server Filtering**: The server only sends log messages at the configured level or higher severity -3. **Notification Delivery**: Log messages are sent as `notifications/message` to the client - -For example, if the client sets the level to `"error"` (severity 4), the server will send messages with levels: `error`, `critical`, `alert`, and `emergency`. - -For more details, see the [MCP Logging specification](https://modelcontextprotocol.io/specification/latest/server/utilities/logging). - -**Usage Example:** - -The client first configures the level with a `logging/setLevel` request: - -```json -{ "jsonrpc": "2.0", "id": 1, "method": "logging/setLevel", "params": { "level": "info" } } -``` - -The server then emits messages at each severity; only those at or above the configured level are delivered: - -```ruby -server = MCP::Server.new(name: "my_server") -transport = MCP::Server::Transports::StdioTransport.new(server) - -server.notify_log_message( - data: { message: "Application started successfully" }, - level: "info" -) - -server.notify_log_message( - data: { message: "Configuration file not found, using defaults" }, - level: "warning" -) - -server.notify_log_message( - data: { - error: "Database connection failed", - details: { host: "localhost", port: 5432 } - }, - level: "error", - logger: "DatabaseLogger" # Optional logger name -) -``` - -**Key Features:** - -- Server has capability `logging` to send log messages -- Messages are only sent if a transport is configured -- Messages are filtered based on the client's configured log level -- If the log level hasn't been set by the client, no messages will be sent - -## Transport Support - -- **stdio**: Notifications are sent as JSON-RPC 2.0 messages to stdout -- **Streamable HTTP**: Notifications are sent as JSON-RPC 2.0 messages over HTTP with streaming (chunked transfer or SSE) diff --git a/docs/_server/mrtr.md b/docs/_server/mrtr.md deleted file mode 100644 index 3113bdf..0000000 --- a/docs/_server/mrtr.md +++ /dev/null @@ -1,87 +0,0 @@ ---- -layout: default -title: Multi Round-Trip Requests -nav_order: 10 -redirect_from: - - /server/multi-round-trip-results/ ---- - -# Multi Round-Trip Requests - -The [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) (MCP 2026-07-28) forbids server-initiated requests. Instead, per SEP-2322, a `tools/call`, `prompts/get`, or `resources/read` handler that -opts in to [`server_context:`](/server/server-context/) may return `MCP::Server::InputRequiredResult.new(input_requests:, request_state:)` to ask the client for -additional input (`elicitation/create`, `sampling/createMessage`, or `roots/list` shapes): - -```ruby -class GreetingTool < MCP::Tool - description "Greets the user by name" - - def self.call(server_context:, **_args) - response = server_context.input_response("user_name") - - unless response - return MCP::Server::InputRequiredResult.new( - input_requests: { - user_name: { - method: "elicitation/create", - params: { - message: "What is your name?", - requestedSchema: { - type: "object", - properties: { name: { type: "string" } }, - required: ["name"], - }, - }, - }, - }, - ) - end - - MCP::Tool::Response.new([{ type: "text", text: "Hello, #{response.dig(:content, :name)}!" }]) - end -end -``` - -## Deterministic Replay - -On the retried request the handler re-runs from the start and reads the answers via -`server_context.input_responses` / `server_context.input_response(key)` and the echoed opaque `server_context.request_state` -(deterministic replay; the server holds no memory between rounds). The server returns `-32021` -when an embedded request needs a client capability the request did not declare. - -## Securing `requestState` - -The echoed `requestState` arrives as client-controlled input: pass `MCP::Server::RequestStateSecurity.new(key:)` (a 32-byte key) via -`Server.new(request_state_security:)` to have it sealed with AES-256-GCM and bound to a TTL plus the originating method, target, and arguments, -all transparently to handlers. Multi-process deployments must share the key across workers; without `request_state_security:` the state crosses -the wire exactly as the handler wrote it and protecting it is the handler author's responsibility. - -```ruby -server = MCP::Server.new( - name: "my_server", - tools: [GreetingTool], - request_state_security: MCP::Server::RequestStateSecurity.new(key: ENV.fetch("MCP_REQUEST_STATE_KEY")), -) -``` - -## `resultType` Stamping - -SEP-2322 also makes `resultType` a required member of every result a 2026-07-28 server returns. The server stamps `resultType: "complete"` -on all results of requests carrying the modern `_meta` envelope (and on `server/discover` results), while results that already carry -a discriminator (`"input_required"`, the tasks extension's `"task"`) keep it. Legacy results stay unstamped, and clients treat an absent -`resultType` as `"complete"` per the spec. - -## Legacy Clients - -Handlers written in the 2026 style serve pre-2026 clients too: when a `tools/call`, `prompts/get`, or `resources/read` handler returns -an `InputRequiredResult` on the legacy wire, the server fulfills it in place of the client's driver. Each `inputRequests` entry is sent -as the equivalent real server-to-client request (`elicitation/create`, `sampling/createMessage`, `roots/list`), associated with -the originating request per SEP-2260; the answers are collected under the same keys, and the handler re-runs with -`server_context.input_responses` populated and the raw `requestState` echoed, the same deterministic replay contract -the modern client driver follows. The shim is on by default (matching the TypeScript SDK) and capped at 8 rounds; -`MCP::Server.new(input_required_legacy_shim: false)` restores the strict rejection of `input_required` results on legacy requests. - -## Client Side - -`call_tool`, `get_prompt`, and `read_resource` drive `input_required` results automatically once the matching handlers are registered; -see the client [Multi Round-Trip Requests](/client/mrtr/) page. diff --git a/docs/_server/notifications.md b/docs/_server/notifications.md deleted file mode 100644 index 7cf9460..0000000 --- a/docs/_server/notifications.md +++ /dev/null @@ -1,68 +0,0 @@ ---- -layout: default -title: Notifications -nav_order: 11 ---- - -# Notifications - -The server supports sending notifications to clients when lists of tools, prompts, or resources change. This enables real-time updates without polling. - -## Notification Methods - -The server provides the following notification methods: - -- `notify_tools_list_changed` - Send a notification when the tools list changes -- `notify_prompts_list_changed` - Send a notification when the prompts list changes -- `notify_resources_list_changed` - Send a notification when the resources list changes -- `notify_log_message` - Send a structured logging notification message (see [Logging](/server/logging/)) - -## Session Scoping - -When using Streamable HTTP transport with multiple clients, each client connection gets its own session. Notifications are scoped as follows: - -- **`report_progress`** and **`notify_log_message`** called via [`server_context`](/server/server-context/) inside a tool handler are automatically sent only to the requesting client. -No extra configuration is needed. -- **`notify_tools_list_changed`**, **`notify_prompts_list_changed`**, and **`notify_resources_list_changed`** are always broadcast to all connected clients, -as they represent server-wide state changes. These should be called on the `server` instance directly. - -On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) (MCP 2026-07-28), clients receive these broadcasts through the `subscriptions/listen` stream; -see [Subscriptions](/server/subscriptions/). - -## Notification Format - -Notifications follow the JSON-RPC 2.0 specification and use these method names: - -- `notifications/tools/list_changed` -- `notifications/prompts/list_changed` -- `notifications/resources/list_changed` -- `notifications/cancelled` (see [Cancellation](/server/cancellation/)) -- `notifications/progress` (see [Progress](/server/progress/)) -- `notifications/message` (see [Logging](/server/logging/)) - -## Broadcasting a List Change - -Call the matching `notify_*` method after changing a server-wide list: - -```ruby -server = MCP::Server.new(name: "my_server") - -# Default Streamable HTTP - session oriented -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - -# When tools change, notify clients -server.define_tool(name: "new_tool") { |**args| MCP::Tool::Response.new([{ type: "text", text: "ok" }]) } -server.notify_tools_list_changed - -# When prompts change, notify clients -server.define_prompt(name: "new_prompt") do |args, server_context:| - MCP::Prompt::Result.new(messages: []) -end -server.notify_prompts_list_changed - -# When resources change, notify clients -server.define_resource(uri: "resource://new", name: "new_resource", mime_type: "text/plain") do - [MCP::Resource::TextContents.new(uri: "resource://new", mime_type: "text/plain", text: "contents")] -end -server.notify_resources_list_changed -``` diff --git a/docs/_server/pagination.md b/docs/_server/pagination.md deleted file mode 100644 index c721f18..0000000 --- a/docs/_server/pagination.md +++ /dev/null @@ -1,78 +0,0 @@ ---- -layout: default -title: Pagination -nav_order: 18 ---- - -# Pagination - -The MCP Ruby SDK supports [pagination](https://modelcontextprotocol.io/specification/latest/server/utilities/pagination) -for list operations that may return large result sets. Pagination uses string cursor tokens carrying a zero-based offset, -treated as opaque by clients: the server decides page size, and the client follows `nextCursor` until the server omits it. - -Pagination applies to `tools/list`, `prompts/list`, `resources/list`, and `resources/templates/list`, -including lists produced by a custom `resources_list_handler`. - -## Enabling Pagination - -Pass `page_size:` to `MCP::Server.new` to split list responses into pages. When `page_size` is omitted (the default), -list responses contain all items in a single response, preserving the pre-pagination behavior. - -```ruby -server = MCP::Server.new( - name: "my_server", - tools: tools, - page_size: 50, -) -``` - -When `page_size` is set, list responses include a `nextCursor` field whenever more pages are available: - -```json -{ - "jsonrpc": "2.0", - "id": 1, - "result": { - "tools": [ - { "name": "example_tool" } - ], - "nextCursor": "50" - } -} -``` - -Invalid cursors (e.g. non-numeric, negative, or out-of-range) are rejected with JSON-RPC error code `-32602 (Invalid params)` per the MCP specification. - -## List Result Caching - -Per SEP-2549, list and read results can carry cache hints telling clients how long a result stays fresh (`ttlMs`, max-age semantics in milliseconds; -`0` means do not cache) and whether shared intermediaries may cache it (`cacheScope`: `"public"` or `"private"`). - -Emission is opt-in: pass `ttl_ms:` and/or `cache_scope:` to `MCP::Server.new` and both fields are added to `tools/list`, `prompts/list`, `resources/list`, -`resources/templates/list`, and `resources/read` results (a missing field is filled with the defaults `ttlMs: 0` / `cacheScope: "private"`, -the scope that keeps a potentially user-dependent result out of shared caches). -When neither is set, responses are serialized exactly as before. -The 2026-07-28 revision makes both hints required on these results, so on requests carrying the modern `_meta` envelope -the server always emits them, filling unset values with the same defaults; legacy protocol versions keep the opt-in behavior. - -```ruby -server = MCP::Server.new( - name: "my_server", - tools: tools, - ttl_ms: 60_000, # results stay fresh for one minute - cache_scope: "private", # only the requesting client may cache them -) -``` - -A `resources_read_handler` can override the hints per result by returning a full result hash instead of bare contents: - -```ruby -server.resources_read_handler do |params| - { contents: [{ uri: params[:uri], mimeType: "text/plain", text: "..." }], ttlMs: 5_000 } -end -``` - -## Client Side - -Iterating pages, fetching whole collections with the `max_pages` guard, and reading the cache hints -on the result structs are documented on the client [Pagination](/client/pagination/) page. diff --git a/docs/_server/ping.md b/docs/_server/ping.md deleted file mode 100644 index d8c6627..0000000 --- a/docs/_server/ping.md +++ /dev/null @@ -1,52 +0,0 @@ ---- -layout: default -title: Ping -nav_order: 15 ---- - -# Ping - -The MCP Ruby SDK supports -the [MCP `ping` utility](https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/ping), -which allows either side of the connection to verify that the peer is still responsive. -A `ping` request has no parameters, and the receiver MUST respond promptly with an empty result. - -{: .note } -> `ping` belongs to the handshake lifecycle: MCP 2026-07-28 removes the method altogether (SEP-2575), -> since requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) are single POST exchanges whose connection -> itself signals liveness, leaving nothing to probe between requests. The server answers `ping` on -> the handshake lifecycle only - a modern request naming it is rejected with `-32601` Method not found - -> and calling `ping` on a `server_context` while serving a modern request raises an error. The long-lived -> [`subscriptions/listen`](/server/subscriptions/) stream is kept alive by SSE keepalive -> frames instead. - -Servers respond to incoming `ping` requests automatically - no setup is required. -Any `MCP::Server` instance replies with an empty result. - -Servers can also send `ping` requests to the client via `ServerSession#ping`. -`ping` is exempt from the SEP-2260 association requirement, so it may also be sent outside a handler. -Inside a tool handler that receives [`server_context:`](/server/server-context/), call `ping` on it: - -```ruby -class HealthCheckTool < MCP::Tool - description "Verifies the client is still responsive" - - def self.call(server_context:) - server_context.ping # => {} on success - - MCP::Tool::Response.new([{ type: "text", text: "client is alive" }]) - end -end -``` - -`#ping` raises `MCP::Server::ValidationError` when the client returns a `result` -that is not a Hash. Transport-level errors (e.g., the client returning a JSON-RPC error) -propagate as exceptions raised by the transport layer. - -Server-to-client requests are bounded by a timeout on the Streamable HTTP transport; see [Timeouts](/server/elicitation/#timeouts). - -## Client Side - -Pinging the server with `MCP::Client#ping` is documented on the client [Ping](/client/ping/) page. -The Ruby client answers the pings sent with `ServerSession#ping` automatically; -see [Answering Server Pings](/client/ping/#answering-server-pings). diff --git a/docs/_server/progress.md b/docs/_server/progress.md deleted file mode 100644 index f82645b..0000000 --- a/docs/_server/progress.md +++ /dev/null @@ -1,64 +0,0 @@ ---- -layout: default -title: Progress -nav_order: 14 ---- - -# Progress - -The MCP Ruby SDK supports progress tracking for long-running tool operations, -following the [MCP Progress specification](https://modelcontextprotocol.io/specification/latest/server/utilities/progress). - -## How Progress Works - -1. **Client Request**: The client sends a `progressToken` in the `_meta` field when calling a tool -2. **Server Notification**: The server sends `notifications/progress` messages back to the client during tool execution -3. **Tool Integration**: Tools call `server_context.report_progress` to report incremental progress - -## Reporting Progress from Tools - -Tools that accept a [`server_context:`](/server/server-context/) parameter can call `report_progress` on it. -The server automatically wraps the context in an `MCP::ServerContext` instance that provides this method: - -```ruby -class LongRunningTool < MCP::Tool - description "A tool that reports progress during execution" - input_schema( - properties: { - count: { type: "integer" }, - }, - required: ["count"] - ) - - def self.call(count:, server_context:) - count.times do |i| - # Do work here. - server_context.report_progress(i + 1, total: count, message: "Processing item #{i + 1}") - end - - MCP::Tool::Response.new([{ type: "text", text: "Done" }]) - end -end -``` - -The `server_context.report_progress` method accepts: - -- `progress` (required) - current progress value (numeric) -- `total:` (optional) - total expected value, so clients can display a percentage -- `message:` (optional) - human-readable status message - -`report_progress` is a no-op when the request carried no `progressToken`, and both numeric and -string tokens are supported. - -{: .note } -> On the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle), progress notifications emitted during a request ride -> the request's own SSE response stream. The bundled transport buffers them and flushes after -> the handler returns, so they preserve order but arrive together with the final response rather -> than in real time. - -## Client Side - -Requesting progress is the client's side of the contract: pass `progress_token:` to `MCP::Client#call_tool` -and the token is sent as `_meta.progressToken`, as shown on the client [Transports](/client/transports/) page. -The bundled client transports do not currently expose a callback for observing the incoming `notifications/progress` messages; -the token's effect is visible on the server side only. diff --git a/docs/_server/prompts.md b/docs/_server/prompts.md deleted file mode 100644 index e8f5a48..0000000 --- a/docs/_server/prompts.md +++ /dev/null @@ -1,194 +0,0 @@ ---- -layout: default -title: Prompts -nav_order: 5 ---- - -# Prompts - -MCP spec includes [Prompts](https://modelcontextprotocol.io/specification/latest/server/prompts), which enable servers to define reusable prompt templates and workflows that clients can easily surface to users and LLMs. - -## Defining Prompts - -The `MCP::Prompt` class provides three ways to create prompts. - -### 1. As a class definition with metadata - -Subclass `MCP::Prompt` and declare the metadata with class-level helpers; `template` builds the result: - -```ruby -class MyPrompt < MCP::Prompt - prompt_name "my_prompt" # Optional - defaults to underscored class name - title "My Prompt" - description "This prompt performs specific functionality..." - arguments [ - MCP::Prompt::Argument.new( - name: "message", - title: "Message Title", - description: "Input message", - required: true - ) - ] - meta({ version: "1.0", category: "example" }) - - class << self - def template(args, server_context:) - MCP::Prompt::Result.new( - description: "Response description", - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("User message") - ), - MCP::Prompt::Message.new( - role: "assistant", - content: MCP::Content::Text.new(args["message"]) - ) - ] - ) - end - end -end - -prompt = MyPrompt -``` - -### 2. Using the `MCP::Prompt.define` method - -`MCP::Prompt.define` builds a prompt from keyword arguments, with the block as its template: - -```ruby -prompt = MCP::Prompt.define( - name: "my_prompt", - title: "My Prompt", - description: "This prompt performs specific functionality...", - arguments: [ - MCP::Prompt::Argument.new( - name: "message", - title: "Message Title", - description: "Input message", - required: true - ) - ], - meta: { version: "1.0", category: "example" } -) do |args, server_context:| - MCP::Prompt::Result.new( - description: "Response description", - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("User message") - ), - MCP::Prompt::Message.new( - role: "assistant", - content: MCP::Content::Text.new(args["message"]) - ) - ] - ) -end -``` - -### 3. Using the `MCP::Server#define_prompt` method - -`MCP::Server#define_prompt` registers the prompt directly on a server instance: - -```ruby -server = MCP::Server.new -server.define_prompt( - name: "my_prompt", - description: "This prompt performs specific functionality...", - arguments: [ - Prompt::Argument.new( - name: "message", - title: "Message Title", - description: "Input message", - required: true - ) - ], - meta: { version: "1.0", category: "example" } -) do |args, server_context:| - Prompt::Result.new( - description: "Response description", - messages: [ - Prompt::Message.new( - role: "user", - content: Content::Text.new("User message") - ), - Prompt::Message.new( - role: "assistant", - content: Content::Text.new(args["message"]) - ) - ] - ) -end -``` - -The [`server_context`](/server/server-context/) parameter is the `server_context` passed into the server and can be used to pass per request information, -e.g. around authentication state or user preferences. - -## Key Components - -- `MCP::Prompt::Argument` - Defines input parameters for the prompt template with name, title, description, and required flag -- `MCP::Prompt::Message` - Represents a message in the conversation with a role and content -- `MCP::Prompt::Result` - The output of a prompt template containing description and messages -- `MCP::Content::Text` - Text content for messages - -## Registering Prompts - -Register prompts with the MCP server: - -```ruby -server = MCP::Server.new( - name: "my_server", - prompts: [MyPrompt], - server_context: { user_id: current_user.id }, -) -``` - -The server will handle prompt listing and execution through the MCP protocol methods: - -- `prompts/list` - Lists all registered prompts and their schemas -- `prompts/get` - Retrieves and executes a specific prompt with arguments - -## Prompts with Image and Embedded Resource Content - -Prompt messages are not limited to text. The same `MCP::Content` types used in [tool responses](/server/tools/) can be used as message content, -letting a prompt template include images or inline resource contents. Unlike tool responses, the content object is passed directly rather than as a hash; -`MCP::Prompt::Message` serializes it when the prompt result is returned: - -```ruby -class CodeReviewPrompt < MCP::Prompt - prompt_name "code_review" - description "Review a source file with an accompanying diagram" - arguments [ - MCP::Prompt::Argument.new(name: "file_uri", description: "URI of the file to review", required: true), - ] - - class << self - def template(args, server_context:) - MCP::Prompt::Result.new( - messages: [ - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::EmbeddedResource.new( - MCP::Resource::TextContents.new( - uri: args["file_uri"], - mime_type: "text/x-ruby", - text: read_source(args["file_uri"]), - ), - ), - ), - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Image.new(architecture_diagram_base64, "image/png"), - ), - MCP::Prompt::Message.new( - role: "user", - content: MCP::Content::Text.new("Please review the code above, using the diagram for context."), - ), - ], - ) - end - end -end -``` diff --git a/docs/_server/resources.md b/docs/_server/resources.md deleted file mode 100644 index f53548a..0000000 --- a/docs/_server/resources.md +++ /dev/null @@ -1,319 +0,0 @@ ---- -layout: default -title: Resources -nav_order: 6 ---- - -# Resources - -MCP spec includes [Resources](https://modelcontextprotocol.io/specification/latest/server/resources). - -## Defining Resources - -Like [tools](/server/tools/) and [prompts](/server/prompts/), resources can be defined in three ways. - -### 1. As a class definition - -Define a class that inherits from `MCP::Resource`, implementing `contents` to serve the resource body: - -```ruby -class MyResource < MCP::Resource - uri "https://example.com/my_resource" - resource_name "my-resource" - title "My Resource" - description "Lorem ipsum dolor sit amet" - mime_type "text/html" - - class << self - def contents - [MCP::Resource::TextContents.new( - uri: uri, - mime_type: mime_type, - text: "Hello from example resource!" - )] - end - end -end - -server = MCP::Server.new( - name: "my_server", - resources: [MyResource], -) -``` - -`resources/read` requests are routed automatically: when the requested URI matches a registered -class-based resource, its `contents` method is called. `contents` may return an array of -`MCP::Resource::TextContents` / `MCP::Resource::BlobContents` objects (or plain hashes), or a single one. -Like tools, `contents` can opt in to a [`server_context:`](/server/server-context/) keyword argument to receive per-request context. - -When class-based resources or resource templates are registered and a `resources/read` request -does not match any of them, the server responds with the standard JSON-RPC Invalid Params error -(`-32602`) carrying the requested URI in the error `data` member, per SEP-2164. - -### 2. Using the `MCP::Resource.define` method - -The block implements `contents`: - -```ruby -resource = MCP::Resource.define( - uri: "https://example.com/my_resource", - name: "my-resource", - mime_type: "text/html", -) do - [MCP::Resource::TextContents.new(uri: uri, mime_type: mime_type, text: "Hello!")] -end -``` - -### 3. Using the `MCP::Server#define_resource` method - -`MCP::Server#define_resource` registers the resource directly on a server instance: - -```ruby -server = MCP::Server.new(name: "my_server") -server.define_resource( - uri: "https://example.com/my_resource", - name: "my-resource", - mime_type: "text/html", -) do - [MCP::Resource::TextContents.new(uri: "https://example.com/my_resource", mime_type: "text/html", text: "Hello!")] -end -``` - -Alternatively, resources can be registered as plain data objects with `MCP::Resource.new`, -in which case the server only lists them: - -```ruby -resource = MCP::Resource.new( - uri: "https://example.com/my_resource", - name: "my-resource", - title: "My Resource", - description: "Lorem ipsum dolor sit amet", - mime_type: "text/html", -) - -server = MCP::Server.new( - name: "my_server", - resources: [resource], -) -``` - -With plain data resources, the server must register a handler for the `resources/read` method to -retrieve a resource dynamically. - -```ruby -server.resources_read_handler do |params| - [{ - uri: params[:uri], - mimeType: "text/plain", - text: "Hello from example resource! URI: #{params[:uri]}" - }] -end -``` - -otherwise `resources/read` requests will be a no-op. Note that a `resources_read_handler` fully replaces -the default `resources/read` handling, including the automatic routing to class-based resources described above. - -To make the resource *list* depend on the request, register a `resources_list_handler`. The block returns the resource collection to serve, -so the visible resources can vary by the authenticated principal or the granted scope. The framework paginates the returned array -and stamps the same cache hints it applies to the constructor-provided resources, so the block returns only the array. -A block that declares `server_context:` receives it: - -```ruby -server.resources_list_handler do |params, server_context:| - server_context[:authenticated] ? real_resources : demo_resources -end -``` - -The block is invoked once per page, so it must return a stable ordering across the pages of one query; the cursor is a positional offset -into the returned collection. When no handler is set, the resources passed to `MCP::Server.new` are served unchanged. - -For unknown URIs, raise `MCP::Server::ResourceNotFoundError` from the handler. -Per SEP-2164, the server then responds with the standard JSON-RPC Invalid Params error (`-32602`) -carrying the requested URI in the error `data` member: - -```ruby -server.resources_read_handler do |params| - resource = lookup(params[:uri]) - raise MCP::Server::ResourceNotFoundError.new(params[:uri], params) unless resource - - [{ uri: params[:uri], mimeType: resource.mime_type, text: resource.body }] -end -``` - -## Reading Binary Resources - -For binary resources, respond with a base64-encoded `blob` field instead of `text`. -The `MCP::Resource::TextContents` and `MCP::Resource::BlobContents` classes build the two contents shapes defined by the spec: - -```ruby -server.resources_read_handler do |params| - case params[:uri] - when "file:///logo.png" - [ - MCP::Resource::BlobContents.new( - uri: params[:uri], - mime_type: "image/png", - data: Base64.strict_encode64(File.binread("logo.png")), - ).to_h, - ] - else - [ - MCP::Resource::TextContents.new( - uri: params[:uri], - mime_type: "text/plain", - text: "Hello from example resource!", - ).to_h, - ] - end -end -``` - -## Resource Templates - -Resource templates follow the same pattern. Class-based templates declare a `uri_template` and -receive the variables extracted from the requested URI as keyword arguments to `contents`: - -```ruby -class UserProfileTemplate < MCP::ResourceTemplate - uri_template "users://{user_id}/profile" - resource_template_name "user-profile" - title "User Profile" - description "Profile data for a user" - mime_type "application/json" - - class << self - def contents(user_id:) - [MCP::Resource::TextContents.new( - uri: "users://#{user_id}/profile", - mime_type: mime_type, - text: { id: user_id }.to_json - )] - end - end -end - -server = MCP::Server.new( - name: "my_server", - resource_templates: [UserProfileTemplate], -) -``` - -A `resources/read` request for `users://42/profile` calls `UserProfileTemplate.contents(user_id: "42")`. -An exact match against a registered resource takes precedence over template matching. -`contents` can also opt in to a `server_context:` keyword argument. - -URI template matching supports simple [RFC 6570](https://www.rfc-editor.org/rfc/rfc6570) level 1 `{variable}` expressions only: - -- Operator expressions such as `{+path}`, `{#fragment}`, or `{?query}` are treated as literal text and never match an expanded URI. -- A variable matches one or more characters excluding `/`. -- Extracted values are not percent-decoded. - -The `MCP::ResourceTemplate.define` and `MCP::Server#define_resource_template` methods are also available, -mirroring the resource variants: - -```ruby -server.define_resource_template( - uri_template: "users://{user_id}/profile", - name: "user-profile", - mime_type: "application/json", -) do |user_id:| - [MCP::Resource::TextContents.new( - uri: "users://#{user_id}/profile", - mime_type: "application/json", - text: { id: user_id }.to_json - )] -end -``` - -Resource templates can also be registered as plain data objects with `MCP::ResourceTemplate.new`, -in which case reads must be served by a `resources_read_handler`: - -```ruby -resource_template = MCP::ResourceTemplate.new( - uri_template: "https://example.com/my_resource_template", - name: "my-resource-template", - title: "My Resource Template", - description: "Lorem ipsum dolor sit amet", - mime_type: "text/html", -) - -server = MCP::Server.new( - name: "my_server", - resource_templates: [resource_template], -) -``` - -Registered templates are listed through the `resources/templates/list` protocol method. -To serve reads for URIs that match a template, extract the variable parts of the URI in your `resources_read_handler`: - -```ruby -resource_template = MCP::ResourceTemplate.new( - uri_template: "file:///items/{item_id}", - name: "item", - mime_type: "application/json", -) - -server = MCP::Server.new(name: "my_server", resource_templates: [resource_template]) - -server.resources_read_handler do |params| - if (match = params[:uri].match(%r{\Afile:///items/(?[^/]+)\z})) - [{ - uri: params[:uri], - mimeType: "application/json", - text: { id: match[:item_id] }.to_json, - }] - else - raise MCP::Server::ResourceNotFoundError.new(params[:uri], params) - end -end -``` - -## Resource Subscriptions - -Resource subscriptions allow clients to monitor specific resources for changes. -When a subscribed resource is updated, the server sends a notification to the client. - -The SDK does not track subscription state internally. -Server developers register handlers and manage their own subscription state. -Three methods are provided: - -- `Server#resources_subscribe_handler` - registers a handler for `resources/subscribe` requests -- `Server#resources_unsubscribe_handler` - registers a handler for `resources/unsubscribe` requests -- `ServerContext#notify_resources_updated` - sends a `notifications/resources/updated` notification to the subscribing client - -```ruby -subscribed_uris = Set.new - -server = MCP::Server.new( - name: "my_server", - resources: [my_resource], - capabilities: { resources: { subscribe: true } }, -) - -server.resources_subscribe_handler do |params| - subscribed_uris.add(params[:uri].to_s) -end - -server.resources_unsubscribe_handler do |params| - subscribed_uris.delete(params[:uri].to_s) -end - -server.define_tool(name: "update_resource") do |server_context:, **args| - if subscribed_uris.include?("test://my-resource") - server_context.notify_resources_updated(uri: "test://my-resource") - end - MCP::Tool::Response.new([MCP::Content::Text.new("Resource updated").to_h]) -end -``` - -The `resources/subscribe` and `resources/unsubscribe` responses are empty results. The one field the spec allows -alongside is `_meta`, so a handler that returns `{ _meta: { ... } }` has it passed through; any other field it -returns is dropped. To convey a subscription identifier or other advisory data to the client, nest it under `_meta` -rather than returning it at the top level, which interoperating clients reject: - -```ruby -server.resources_subscribe_handler do |params| - id = subscriptions.create(params[:uri].to_s) - { _meta: { "myapp.example/subscriptionId" => id } } -end -``` diff --git a/docs/_server/roots.md b/docs/_server/roots.md deleted file mode 100644 index a3341c6..0000000 --- a/docs/_server/roots.md +++ /dev/null @@ -1,82 +0,0 @@ ---- -layout: default -title: Roots -nav_order: 7 ---- - -# Roots - -The Model Context Protocol allows servers to request filesystem roots from clients through the `roots/list` method. -Roots define the boundaries of where a server can operate, providing a list of directories and files the client has made available. - -{: .warning } -> MCP Roots (`roots/list` and `notifications/roots/list_changed`) is deprecated as of protocol version `2026-07-28` (SEP-2577), -> while remaining fully supported under `2025-11-25`. Prefer tool parameters, resource URIs, server configuration, or environment -> variables for new servers. A client declaring the `roots` capability on a modern connection emits a deprecation warning. - -{: .important } -> Per SEP-2260, server-to-client requests (`roots/list`, `sampling/createMessage`, `elicitation/create`) must be associated with -> an originating client request (`ping` is exempt). Use the `server_context` passed to your handler, which stamps the association -> automatically and routes the request onto the originating POST stream on the Streamable HTTP transport. Calling the corresponding -> `ServerSession` methods without `related_request_id:` still works but emits a deprecation warning. - -Server-to-client requests are bounded by a timeout on the Streamable HTTP transport; see [Timeouts](/server/elicitation/#timeouts). - -## Key Concepts - -- **Server-to-Client Request**: Like [sampling](/server/sampling/), roots listing is initiated by the server -- **Client Capability**: Clients must declare `roots` capability during initialization -- **Change Notifications**: Clients that support `roots.listChanged` send `notifications/roots/list_changed` when roots change - -## Using Roots in Tools - -Tools that accept a [`server_context:`](/server/server-context/) parameter can call `list_roots` on it. -The request is automatically routed to the correct client session: - -```ruby -class FileSearchTool < MCP::Tool - description "Search files within the client's project roots" - input_schema( - properties: { - query: { type: "string" } - }, - required: ["query"] - ) - - def self.call(query:, server_context:) - roots = server_context.list_roots - root_uris = roots[:roots].map { |root| root[:uri] } - - MCP::Tool::Response.new([{ - type: "text", - text: "Searching in roots: #{root_uris.join(", ")}" - }]) - end -end -``` - -Result contains an array of root objects: - -```ruby -{ - roots: [ - { uri: "file:///home/user/projects/myproject", name: "My Project" }, - { uri: "file:///home/user/repos/backend", name: "Backend Repository" } - ] -} -``` - -## Handling Root Changes - -Register a callback to be notified when the client's roots change: - -```ruby -server.roots_list_changed_handler do - puts "Client's roots have changed, tools will see updated roots on next call." -end -``` - -## Error Handling - -- Raises `RuntimeError` if client does not support `roots` capability -- Raises `StandardError` if client returns an error response diff --git a/docs/_server/sampling.md b/docs/_server/sampling.md deleted file mode 100644 index af37df0..0000000 --- a/docs/_server/sampling.md +++ /dev/null @@ -1,87 +0,0 @@ ---- -layout: default -title: Sampling -nav_order: 8 ---- - -# Sampling - -The Model Context Protocol allows servers to request LLM completions from clients through the `sampling/createMessage` method. -This enables servers to leverage the client's LLM capabilities without needing direct access to AI models. - -{: .warning } -> MCP Sampling (`sampling/createMessage`) is deprecated as of protocol version `2026-07-28` (SEP-2577), -> while remaining fully supported under `2025-11-25`. New servers should call LLM provider APIs directly. -> A client declaring the `sampling` capability on a modern connection emits a deprecation warning. - -{: .important } -> Per SEP-2260, server-to-client requests (`roots/list`, `sampling/createMessage`, `elicitation/create`) must be associated with -> an originating client request (`ping` is exempt). Use the `server_context` passed to your handler, which stamps the association -> automatically and routes the request onto the originating POST stream on the Streamable HTTP transport. Calling the corresponding -> `ServerSession` methods without `related_request_id:` still works but emits a deprecation warning. - -Server-to-client requests are bounded by a timeout on the Streamable HTTP transport; see [Timeouts](/server/elicitation/#timeouts). - -## Key Concepts - -- **Server-to-Client Request**: Unlike typical MCP methods (client to server), sampling is initiated by the server -- **Client Capability**: Clients must declare `sampling` capability during initialization -- **Tool Support**: When using tools in sampling requests, clients must declare `sampling.tools` capability -- **Human-in-the-Loop**: Clients can implement user approval before forwarding requests to LLMs - -## Using Sampling in Tools - -Tools that accept a [`server_context:`](/server/server-context/) parameter can call `create_sampling_message` on it. -The request is automatically routed to the correct client session: - -```ruby -class SummarizeTool < MCP::Tool - description "Summarize text using LLM" - input_schema( - properties: { - text: { type: "string" } - }, - required: ["text"] - ) - - def self.call(text:, server_context:) - result = server_context.create_sampling_message( - messages: [ - { role: "user", content: { type: "text", text: "Please summarize: #{text}" } } - ], - max_tokens: 500 - ) - - MCP::Tool::Response.new([{ - type: "text", - text: result[:content][:text] - }]) - end -end - -server = MCP::Server.new(name: "my_server", tools: [SummarizeTool]) -``` - -## Parameters - -Required: - -- `messages:` (Array) - Array of message objects with `role` and `content` -- `max_tokens:` (Integer) - Maximum tokens in the response - -Optional: - -- `system_prompt:` (String) - System prompt for the LLM -- `model_preferences:` (Hash) - Model selection preferences (e.g., `{ intelligencePriority: 0.8 }`) -- `include_context:` (String) - Context inclusion: `"none"`, `"thisServer"`, or `"allServers"` (soft-deprecated) -- `temperature:` (Float) - Sampling temperature -- `stop_sequences:` (Array) - Sequences that stop generation -- `metadata:` (Hash) - Additional metadata -- `tools:` (Array) - Tools available to the LLM (requires `sampling.tools` capability) -- `tool_choice:` (Hash) - Tool selection mode (e.g., `{ mode: "auto" }`) - -## Error Handling - -- Raises `RuntimeError` if client does not support `sampling` capability -- Raises `RuntimeError` if `tools` are used but client lacks `sampling.tools` capability -- Raises `StandardError` if client returns an error response diff --git a/docs/_server/server-context.md b/docs/_server/server-context.md deleted file mode 100644 index f45f576..0000000 --- a/docs/_server/server-context.md +++ /dev/null @@ -1,111 +0,0 @@ ---- -layout: default -title: Server Context -nav_order: 19 ---- - -# Server Context - -The `server_context` is a user-defined hash that is passed into the server instance and made available to [tool](/server/tools/) and [prompt](/server/prompts/) calls. -It can be used to provide contextual information such as authentication state, user IDs, or request-specific data. - -**Type:** - -```ruby -server_context: { [String, Symbol] => Any } -``` - -**Example:** - -```ruby -server = MCP::Server.new( - name: "my_server", - server_context: { user_id: current_user.id, request_id: request.uuid } -) -``` - -This hash is then passed as the `server_context` keyword argument to tool and prompt calls. -Note that the exception reporter does not receive this user-defined hash, and instrumentation -callbacks omit it unless you opt in with `instrument_server_context`. -See the [Configuration](/server/configuration/) page for the arguments they receive. - -## Request-specific `_meta` Parameter - -The MCP protocol supports a special [`_meta` parameter](https://modelcontextprotocol.io/specification/latest/basic#general-fields) in requests that allows clients to pass request-specific metadata. The server automatically extracts this parameter and makes it available to tools and prompts as a nested field within the `server_context`. - -{: .note } -> `_meta` is only merged when `server_context` is a `Hash` (or `nil`, in which case a new `{ _meta: ... }` hash is synthesized). -> If you assign a non-`Hash` value to `server_context`, `_meta` is not merged and tools will not see it -> under `server_context[:_meta]`. Keep `server_context` as a `Hash` if your tools need access to `_meta`. - -**Access Pattern:** - -When a client includes `_meta` in the request params, it becomes available as `server_context[:_meta]`: - -```ruby -class MyTool < MCP::Tool - def self.call(message:, server_context:) - # Access provider-specific metadata - session_id = server_context.dig(:_meta, :session_id) - request_id = server_context.dig(:_meta, :request_id) - - # Access server's original context - user_id = server_context.dig(:user_id) - - MCP::Tool::Response.new([{ - type: "text", - text: "Processing for user #{user_id} in session #{session_id}" - }]) - end -end -``` - -**Client Request Example:** - -A `tools/call` request carrying `_meta`, as read by the tool above: - -```json -{ - "jsonrpc": "2.0", - "id": 1, - "method": "tools/call", - "params": { - "name": "my_tool", - "arguments": { "message": "Hello" }, - "_meta": { - "session_id": "abc123", - "request_id": "req_456" - } - } -} -``` - -### Distributed Tracing - -Per SEP-414, the keys `traceparent`, `tracestate`, and `baggage` are reserved un-prefixed `_meta` keys for propagating -[W3C Trace Context](https://www.w3.org/TR/trace-context/) across MCP requests. The SDK guarantees these keys pass through -incoming request `_meta` untouched, and exposes their names as constants on `MCP::TraceContext` (`TRACEPARENT_META_KEY`, -`TRACESTATE_META_KEY`, `BAGGAGE_META_KEY`, and `META_KEYS`). The SDK does not depend on OpenTelemetry; bridge the values -to your tracing system yourself: - -```ruby -class TracedTool < MCP::Tool - def self.call(message:, server_context:) - traceparent = server_context.dig(:_meta, :traceparent) - # Hand traceparent/tracestate/baggage to your tracing library - # (e.g. the opentelemetry-ruby gems) to continue the caller's trace. - - MCP::Tool::Response.new([{ type: "text", text: "ok" }]) - end -end -``` - -On the client side, every request method (`call_tool`, `read_resource`, `get_prompt`, `complete`, `ping`, and the `list_*` methods) -accepts a `meta:` keyword to inject these keys into the outgoing request, so trace context can flow on every request: - -```ruby -meta = { MCP::TraceContext::TRACEPARENT_META_KEY => "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01" } - -client.call_tool(tool: tool, arguments: { message: "Hello" }, meta: meta) -client.read_resource(uri: "file:///report.txt", meta: meta) -``` diff --git a/docs/_server/subscriptions.md b/docs/_server/subscriptions.md deleted file mode 100644 index 22116aa..0000000 --- a/docs/_server/subscriptions.md +++ /dev/null @@ -1,83 +0,0 @@ ---- -layout: default -title: Subscriptions -nav_order: 12 -redirect_from: - - /server/notification-subscriptions/ ---- - -# Subscriptions - -`subscriptions/listen` is the long-lived notification subscription stream of MCP 2026-07-28 (SEP-2575), -replacing the legacy HTTP GET listening stream. - -## Subscribing - -The client opts in via the `notifications` filter (`toolsListChanged` / `promptsListChanged` / `resourcesListChanged` / `resourceSubscriptions`), -the server acknowledges the honored subset with `notifications/subscriptions/acknowledged` as the first stream message, -and every delivered notification carries the correlating `io.modelcontextprotocol/subscriptionId` in `_meta`. -The honored subset follows the capabilities the server declares (`listChanged` and `subscribe` flags). - -The client opens the stream with a `subscriptions/listen` request: - -```json -{ - "jsonrpc": "2.0", - "id": "listen-1", - "method": "subscriptions/listen", - "params": { - "notifications": { "toolsListChanged": true, "resourceSubscriptions": ["file:///a.txt"] }, - "_meta": { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { "name": "my_client", "version": "1.0.0" }, - "io.modelcontextprotocol/clientCapabilities": {} - } - } -} -``` - -The first SSE event on the stream is the acknowledgement: - -```json -{ - "jsonrpc": "2.0", - "method": "notifications/subscriptions/acknowledged", - "params": { - "notifications": { "toolsListChanged": true, "resourceSubscriptions": ["file:///a.txt"] }, - "_meta": { "io.modelcontextprotocol/subscriptionId": "listen-1" } - } -} -``` - -## Delivery Semantics - -A stream delivers only the changes that happen after its acknowledgement; it is not a replay log. -Nothing is queued while no stream is connected, and a dropped stream is gone together with anything it missed. -Clients fetch the current state after subscribing and treat each notification as a cue to refetch, -rather than as a payload. - -## Transport Support - -The stream is served on the Streamable HTTP modern path; stdio answers `-32601`. -A host that cannot hold an SSE response open (such as the [Rails controller pattern](/server/transports/#rails-controller), -which buffers the body) declines the method with `serve_subscriptions_listen: false`, answering `-32601` and dropping -the `listChanged`/`subscribe` flags from discovery. - -## Limits and Keepalives - -Concurrent streams are capped by `max_listen_subscriptions:` (default 1000; pass `nil` to remove the cap), and each stream receives an SSE keepalive -comment frame every `listen_keepalive_interval:` seconds (default 15) so a dropped connection frees its slot; pass `listen_keepalive_interval: nil` -when an upstream proxy already keeps the stream alive. - -```ruby -transport = MCP::Server::Transports::StreamableHTTPTransport.new( - server, - max_listen_subscriptions: 500, - listen_keepalive_interval: 30, -) -``` - -A stream stays open until the client closes the connection; on graceful shutdown via `transport.close`, -each open stream receives its `subscriptions/listen` response before closing. - -See [Notifications](/server/notifications/) for the notification types themselves and their session scoping. diff --git a/docs/_server/tools.md b/docs/_server/tools.md deleted file mode 100644 index 0ebf6fe..0000000 --- a/docs/_server/tools.md +++ /dev/null @@ -1,419 +0,0 @@ ---- -layout: default -title: Tools -nav_order: 4 ---- - -# Tools - -MCP spec includes [Tools](https://modelcontextprotocol.io/specification/latest/server/tools) which provide functionality to LLM apps. - -## Defining Tools - -This gem provides a `MCP::Tool` class that can be used to create tools in three ways. - -### 1. As a class definition - -Subclass `MCP::Tool` and declare the metadata with class-level helpers; `call` implements the tool: - -```ruby -class MyTool < MCP::Tool - title "My Tool" - description "This tool performs specific functionality..." - input_schema( - properties: { - message: { type: "string" }, - }, - required: ["message"] - ) - output_schema( - properties: { - result: { type: "string" }, - success: { type: "boolean" }, - timestamp: { type: "string", format: "date-time" } - }, - required: ["result", "success", "timestamp"] - ) - annotations( - read_only_hint: true, - destructive_hint: false, - idempotent_hint: true, - open_world_hint: false, - title: "My Tool" - ) - - def self.call(message:, server_context:) - MCP::Tool::Response.new([{ type: "text", text: "OK" }]) - end -end - -tool = MyTool -``` - -### 2. Using the `MCP::Tool.define` method - -`MCP::Tool.define` builds a tool from keyword arguments, with the block as its implementation: - -```ruby -tool = MCP::Tool.define( - name: "my_tool", - title: "My Tool", - description: "This tool performs specific functionality...", - annotations: { - read_only_hint: true, - title: "My Tool" - } -) do |args, server_context:| - MCP::Tool::Response.new([{ type: "text", text: "OK" }]) -end -``` - -### 3. Using the `MCP::Server#define_tool` method - -`MCP::Server#define_tool` registers the tool directly on a server instance: - -```ruby -server = MCP::Server.new -server.define_tool( - name: "my_tool", - description: "This tool performs specific functionality...", - annotations: { - title: "My Tool", - read_only_hint: true - } -) do |args, server_context:| - Tool::Response.new([{ type: "text", text: "OK" }]) -end -``` - -The [`server_context`](/server/server-context/) parameter is the `server_context` passed into the server and can be used to pass per request information, -e.g. around authentication state. - -## Tool argument keys - -Tool arguments are delivered as a `Hash` whose keys are Ruby symbols at every nesting level, including nested objects -and objects inside arrays. The transports parse incoming JSON with `JSON.parse(..., symbolize_names: true)`, -so by the time a tool runs, a wire payload such as `{"payload": {"subject": "greet"}}` arrives as `{ payload: { subject: "greet" } }`. - -This means top-level values are bound through keyword arguments (`def call(message:, payload: nil, server_context:)`), -and nested objects must be read with symbol keys: - -```ruby -class ExampleTool < MCP::Tool - description "Echoes a nested argument" - input_schema( - properties: { - message: { type: "string" }, - payload: { - type: "object", - properties: { - subject: { type: "string" }, - } - } - }, - required: ["message"] - ) - - def self.call(message:, payload: nil, server_context:) - subject = payload && payload[:subject] # symbol key, not payload["subject"] - MCP::Tool::Response.new([{ - type: "text", - text: "Message: #{message}; subject: #{subject}" - }]) - end -end -``` - -Reading a nested value with a string key (`payload["subject"]`) returns `nil`. This is a Ruby-specific contract: -Top-level keyword arguments require symbol keys, and parsing JSON with `symbolize_names: true` symbolizes nested objects too. - -Calling a tool directly in a test with `MyTool.call(payload: { "subject" => "greet" }, server_context: nil)` passes string keys -that a transport never delivers, so string-key access can pass tests yet fail against a real client. -Exercise a tool under the delivered shape by round-tripping the arguments through JSON the same way a transport does: - -```ruby -delivered = JSON.parse(JSON.generate(arguments), symbolize_names: true) -MyTool.call(**delivered, server_context: nil) -``` - -## Tool Annotations - -Tools can include annotations that provide additional metadata about their behavior. The following annotations are supported: - -- `destructive_hint`: Indicates if the tool performs destructive operations. Defaults to true -- `idempotent_hint`: Indicates if the tool's operations are idempotent. Defaults to false -- `open_world_hint`: Indicates if the tool operates in an open world context. Defaults to true -- `read_only_hint`: Indicates if the tool only reads data (doesn't modify state). Defaults to false -- `title`: A human-readable title for the tool - -Annotations can be set either through the class definition using the `annotations` class method or when defining a tool using the `define` method. - -{: .note } -> This **Tool Annotations** feature is supported starting from `protocol_version: '2025-03-26'`. - -## Tool Output Schemas - -Tools can optionally define an `output_schema` to specify the expected structure of their results. This works similarly to how `input_schema` is defined and can be used in three ways. - -### 1. Class definition with `output_schema` - -Declare the schema with the `output_schema` class helper, alongside `input_schema`: - -```ruby -class WeatherTool < MCP::Tool - tool_name "get_weather" - description "Get current weather for a location" - - input_schema( - properties: { - location: { type: "string" }, - units: { type: "string", enum: ["celsius", "fahrenheit"] } - }, - required: ["location"] - ) - - output_schema( - properties: { - temperature: { type: "number" }, - condition: { type: "string" }, - humidity: { type: "integer" } - }, - required: ["temperature", "condition", "humidity"] - ) - - def self.call(location:, units: "celsius", server_context:) - # Call weather API and structure the response - api_response = WeatherAPI.fetch(location, units) - weather_data = { - temperature: api_response.temp, - condition: api_response.description, - humidity: api_response.humidity_percent - } - - output_schema.validate_result(weather_data) - - MCP::Tool::Response.new([{ - type: "text", - text: weather_data.to_json - }]) - end -end -``` - -### 2. Using `Tool.define` with `output_schema` - -Pass the schema as the `output_schema:` keyword argument: - -```ruby -tool = MCP::Tool.define( - name: "calculate_stats", - description: "Calculate statistics for a dataset", - input_schema: { - properties: { - numbers: { type: "array", items: { type: "number" } } - }, - required: ["numbers"] - }, - output_schema: { - properties: { - mean: { type: "number" }, - median: { type: "number" }, - count: { type: "integer" } - }, - required: ["mean", "median", "count"] - } -) do |args, server_context:| - # Calculate statistics and validate against schema - MCP::Tool::Response.new([{ type: "text", text: "Statistics calculated" }]) -end -``` - -### 3. Using `OutputSchema` objects - -Construct an `MCP::Tool::OutputSchema` object explicitly: - -```ruby -class DataTool < MCP::Tool - output_schema MCP::Tool::OutputSchema.new( - properties: { - success: { type: "boolean" }, - data: { type: "object" } - }, - required: ["success"] - ) -end -``` - -Output schema may also describe an array of objects: - -```ruby -class WeatherTool < MCP::Tool - output_schema( - type: "array", - items: { - properties: { - temperature: { type: "number" }, - condition: { type: "string" }, - humidity: { type: "integer" } - }, - required: ["temperature", "condition", "humidity"] - } - ) -end -``` - -Please note: in this case, you must provide `type: "array"`. The default type for output schemas is `object`, -applied only when the schema declares no root keyword (`type`, `$ref`, `oneOf`, `anyOf`, `allOf`, `not`, `if`, `const`, `enum`). - -Per SEP-2106, an output schema may be any valid JSON Schema 2020-12 document, including a primitive root -(`{ type: "string" }`) or a root-level composition: - -```ruby -class FlexibleTool < MCP::Tool - output_schema( - oneOf: [ - { type: "string" }, - { type: "array", items: { type: "number" } } - ] - ) -end -``` - -Input schemas keep `type: "object"` at the root but accept the full 2020-12 vocabulary below it -(`$defs`/`$ref`, `oneOf`/`anyOf`/`allOf`/`not`, `if`/`then`/`else`). Two resource bounds apply to -all tool schemas: only same-document `$ref`s (starting with `#`) are accepted, and documents are -capped at `MCP::Tool::Schema::MAX_SCHEMA_DEPTH` nesting levels and `MCP::Tool::Schema::MAX_SUBSCHEMA_COUNT` subschema objects; -violations raise `ArgumentError` at construction time. - -MCP spec for the [Output Schema](https://modelcontextprotocol.io/specification/latest/server/tools#output-schema) specifies that: - -- **Server Validation**: Servers MUST provide structured results that conform to the output schema -- **Client Validation**: Clients SHOULD validate structured results against the output schema -- **Better Integration**: Enables strict schema validation, type information, and improved developer experience -- **Backward Compatibility**: Tools returning structured content SHOULD also include serialized JSON in a TextContent block - -The output schema follows standard JSON Schema format and helps ensure consistent data exchange between MCP servers and clients. - -By default, server-side validation of tool results against `output_schema` is disabled for backwards compatibility. -To validate successful tool responses, enable `validate_tool_call_results` on the server [configuration](/server/configuration/): - -```ruby -configuration = MCP::Configuration.new(validate_tool_call_results: true) -server = MCP::Server.new( - name: "example_server", - tools: [WeatherTool], - configuration: configuration -) -``` - -When enabled, successful tool responses for tools with an `output_schema` must include `structured_content` that conforms to the schema. -Error responses are not validated against the output schema. - -## Tool Responses with Structured Content - -Tools can return structured data alongside text content using the `structured_content` parameter. - -The structured content will be included in the JSON-RPC response as the `structuredContent` field. - -Per SEP-2106, `structured_content` may be any JSON value, not only an object. When a tool returns a non-object value (e.g. an array) -without providing any content blocks, the server automatically mirrors it into `content` as serialized JSON text so older clients -that only read `content` still receive the data. - -```ruby -class WeatherTool < MCP::Tool - description "Get current weather and return structured data" - - def self.call(location:, units: "celsius", server_context:) - # Call weather API and structure the response - api_response = WeatherAPI.fetch(location, units) - weather_data = { - temperature: api_response.temp, - condition: api_response.description, - humidity: api_response.humidity_percent - } - - output_schema.validate_result(weather_data) - - MCP::Tool::Response.new( - [{ - type: "text", - text: weather_data.to_json - }], - structured_content: weather_data - ) - end -end -``` - -## Tool Responses with Errors - -Tools can return error information alongside text content using the `error` parameter. - -The error will be included in the JSON-RPC response as the `isError` field. - -```ruby -class WeatherTool < MCP::Tool - description "Get current weather and return structured data" - - def self.call(server_context:) - # Do something here - content = {} - - MCP::Tool::Response.new( - [{ - type: "text", - text: content.to_json - }], - structured_content: content, - error: true - ) - end -end -``` - -## Tool Responses with Image, Audio, and Embedded Resources - -Tool responses are not limited to text. The `MCP::Content` module provides `Image`, `Audio`, and `EmbeddedResource` content types, -which serialize to the `image`, `audio`, and `resource` content blocks defined by the MCP spec. Image and audio data is passed as -a base64-encoded string together with its MIME type: - -```ruby -class ChartTool < MCP::Tool - description "Render a chart as a PNG image" - - def self.call(server_context:) - MCP::Tool::Response.new([ - MCP::Content::Text.new("Here is the rendered chart:").to_h, - MCP::Content::Image.new(Base64.strict_encode64(render_chart_png), "image/png").to_h, - ]) - end -end - -class SpeechTool < MCP::Tool - description "Synthesize speech audio" - - def self.call(server_context:) - MCP::Tool::Response.new([ - MCP::Content::Audio.new(Base64.strict_encode64(synthesize_wav), "audio/wav").to_h, - ]) - end -end -``` - -An [embedded resource](/server/resources/) wraps `MCP::Resource::TextContents` or `MCP::Resource::BlobContents`, allowing a tool to return resource contents inline: - -```ruby -class ReportTool < MCP::Tool - description "Return a report as an embedded resource" - - def self.call(server_context:) - contents = MCP::Resource::TextContents.new( - uri: "report://monthly", - mime_type: "application/json", - text: { total: 42 }.to_json, - ) - - MCP::Tool::Response.new([MCP::Content::EmbeddedResource.new(contents).to_h]) - end -end -``` diff --git a/docs/_server/transports.md b/docs/_server/transports.md deleted file mode 100644 index 009c506..0000000 --- a/docs/_server/transports.md +++ /dev/null @@ -1,288 +0,0 @@ ---- -layout: default -title: Transports -nav_order: 2 ---- - -# Transports - -The server ships two transports: [stdio](#stdio-transport) for command-line and desktop integrations, -and [Streamable HTTP](#streamable-http-transport) for web deployments. -This page covers starting each transport, mounting the HTTP transport in Rack and Rails applications, -and its deployment, session, and security settings. - -## Stdio Transport - -If you want to build a local command-line application, you can use the stdio transport: - -```ruby -require "mcp" - -# Create a simple tool -class ExampleTool < MCP::Tool - description "A simple example tool that echoes back its arguments" - input_schema( - properties: { - message: { type: "string" }, - }, - required: ["message"] - ) - - class << self - def call(message:, server_context:) - MCP::Tool::Response.new([{ - type: "text", - text: "Hello from example tool! Message: #{message}", - }]) - end - end -end - -# Set up the server -server = MCP::Server.new( - name: "example_server", - tools: [ExampleTool], -) - -# Create and start the transport -transport = MCP::Server::Transports::StdioTransport.new(server) -transport.open -``` - -`StdioTransport.new` accepts an optional `max_line_bytes:` keyword that caps the byte length of a single newline-delimited request frame. A frame that reaches this limit without a newline is rejected and the connection is closed, preventing unbounded memory growth from a peer that never emits a newline. It defaults to `4 * 1024 * 1024` (4 MiB). - -You can run this script and then type in requests to the server at the command line. - -```console -$ ruby examples/stdio_server.rb -{"jsonrpc":"2.0","id":"1","method":"ping"} -{"jsonrpc":"2.0","id":"2","method":"tools/list"} -{"jsonrpc":"2.0","id":"3","method":"tools/call","params":{"name":"example_tool","arguments":{"message":"Hello"}}} -``` - -## Streamable HTTP Transport - -`MCP::Server::Transports::StreamableHTTPTransport` is a standard Rack app, so it can be mounted in any Rack-compatible framework. -The following examples show two common integration styles in Rails. - -{: .important } -> On the legacy handshake lifecycle, `MCP::Server::Transports::StreamableHTTPTransport` stores session and -> SSE stream state in memory, so it must run in a single process. Use a single-process server (e.g., Puma with -> `workers 0`). Multi-process configurations (Unicorn, or Puma with `workers > 0`) fork separate processes that -> do not share memory, which breaks session management and SSE connections. -> -> When running multiple server instances behind a load balancer, configure your load balancer to use -> sticky sessions (session affinity) so that requests with the same `Mcp-Session-Id` header are always -> routed to the same instance. -> -> Stateless mode (`stateless: true`) does not use sessions and works with any server configuration. -> Requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) (MCP 2026-07-28) are likewise sessionless single exchanges and work -> with any configuration, with two caveats: a [`subscriptions/listen`](/server/subscriptions/) stream -> is held in memory by the process that accepted it, so only notifications emitted in that process reach it, -> and the [multi round-trip](/server/mrtr/) `requestState` crosses workers only when they -> share a `RequestStateSecurity` key. - -{: .important } -> Per MCP 2025-11-25, `StreamableHTTPTransport` validates the `Host` and `Origin` headers by default to -> prevent DNS rebinding attacks against locally bound servers, rejecting unauthorized values with HTTP 403. -> `Host` is allowed for the loopback defaults (`127.0.0.1`, `::1`, `localhost`), and an `Origin` header, -> when present, must be same-origin or explicitly allow-listed. Non-browser clients that send no `Origin` -> header are unaffected. -> -> Deployments behind a reverse proxy or bound to a non-loopback interface must widen the allow lists: -> -> ```ruby -> transport = MCP::Server::Transports::StreamableHTTPTransport.new( -> server, -> allowed_hosts: ["mcp.example.com"], -> allowed_origins: ["https://app.example.com"], -> ) -> ``` -> -> An `allowed_hosts:` entry matches either the bare host name (any port) or the full `host:port` value, -> so both `"mcp.example.com"` and `"mcp.example.com:8443"` work. Pass `dns_rebinding_protection: false` -> to disable the check entirely (e.g., when an upstream proxy or middleware already validates `Host`/`Origin`). -> The check runs before any lifecycle dispatch, so it protects requests of -> the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) as well. - -### Rails (mount) - -`StreamableHTTPTransport` is a Rack app that can be mounted directly in Rails routes: - -```ruby -# config/routes.rb -server = MCP::Server.new( - name: "my_server", - title: "Example Server Display Name", - version: "1.0.0", - instructions: "Use the tools of this server as a last resort", - tools: [SomeTool, AnotherTool], - prompts: [MyPrompt], -) -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - -Rails.application.routes.draw do - mount transport => "/mcp" -end -``` - -`mount` directs all HTTP methods on `/mcp` to the transport. `StreamableHTTPTransport` internally dispatches -`POST` (client-to-server JSON-RPC messages, with responses optionally streamed via SSE), -`GET` (optional standalone SSE stream for server-to-client messages), and `DELETE` (session termination) per -the [MCP Streamable HTTP transport spec](https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#streamable-http), -so no additional route configuration is needed. - -A complete runnable application using this approach is available in [`examples/rails`](https://github.com/modelcontextprotocol/ruby-sdk/tree/main/examples/rails). - -### Rails (controller) - -While the mount approach creates a single server at boot time, the controller approach creates a new server per request. -This allows you to customize tools, prompts, or configuration based on the request (e.g., different tools per route). - -`StreamableHTTPTransport#handle_request` returns proper HTTP status codes (e.g., 202 Accepted for notifications): - -```ruby -class McpController < ActionController::API - def create - server = MCP::Server.new( - name: "my_server", - title: "Example Server Display Name", - version: "1.0.0", - instructions: "Use the tools of this server as a last resort", - tools: [SomeTool, AnotherTool], - prompts: [MyPrompt], - server_context: { user_id: current_user.id }, - ) - # Since the `MCP-Session-Id` is not shared across requests, `stateless: true` is set, - # and since `render` buffers the whole body, `subscriptions/listen` streams are declined. - transport = MCP::Server::Transports::StreamableHTTPTransport.new( - server, - stateless: true, - serve_subscriptions_listen: false, - ) - status, headers, body = transport.handle_request(request) - - render(json: body.first, status: status, headers: headers) - end -end -``` - -{: .important } -> The controller pattern builds a fresh transport per request and `render` buffers the whole body, -> so it cannot serve the open SSE stream that [`subscriptions/listen`](/server/subscriptions/) needs: -> without `serve_subscriptions_listen: false`, that request returns a streaming `Proc` body -> that `body.first` cannot render, and a modern client's notification stream fails with a 500. -> With the flag, the method answers 404 with JSON-RPC `-32601`, and `server/discover` stops -> advertising the `listChanged`/`subscribe` capability flags, so well-behaved clients do not ask. -> To actually serve listen streams, use the [mount approach](#rails-mount). - -### Stateless Mode - -You can use Stateless Streamable HTTP, where notifications are not supported and all calls are request/response interactions. -This mode allows for easy multi-node deployment. -Set `stateless: true` in `MCP::Server::Transports::StreamableHTTPTransport.new` (`stateless` defaults to `false`): - -```ruby -# Stateless Streamable HTTP - session-less -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, stateless: true) -``` - -In stateless mode, each POST is fully self-contained per SEP-2567: no `Mcp-Session-Id` is issued or required, -handlers run against an ephemeral per-request session (so client identity never leaks across requests or onto the shared server), -and repeated `initialize` requests are permitted. Request-scoped notifications such as progress and log messages are skipped -(there is no stream to deliver them), while server-to-client requests (`sampling/createMessage`, `roots/list`, `elicitation/create`) raise an error. - -{: .note } -> This transport option is distinct from the sessionless [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) of MCP 2026-07-28. -> The option governs how handshake-lifecycle clients are served; modern requests carry their own `_meta` envelope -> and are served as single exchanges whether or not `stateless: true` is set. - -### JSON Response Mode - -You can enable JSON response mode, where the server returns `application/json` instead of `text/event-stream`. -Set `enable_json_response: true` in `MCP::Server::Transports::StreamableHTTPTransport.new`: - -```ruby -# JSON response mode -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, enable_json_response: true) -``` - -In JSON response mode, the POST response is a single JSON object, so server-to-client messages -that need to arrive during request processing are not supported: -request-scoped notifications (`progress`, `log`) are silently dropped, and all server-to-client requests -(`sampling/createMessage`, `roots/list`, `elicitation/create`) raise an error. -Session-scoped standalone notifications (`resources/updated`, `elicitation/complete`) and -broadcast notifications (`tools/list_changed`, etc.) still flow to clients connected to the GET SSE stream. -This mode is suitable for simple tool servers that do not need server-initiated requests. - -{: .note } -> Like [stateless mode](#stateless-mode), this option applies to handshake-lifecycle clients only. -> Requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) of MCP 2026-07-28 ignore `enable_json_response:` -> and are served as SSE-framed single exchanges, so request-scoped notifications still reach the client. - -### Session Limits - -By default, stateful sessions are bounded so an `initialize` flood cannot retain sessions until memory is exhausted: -they expire after `session_idle_timeout` seconds of inactivity (default 1800, i.e. 30 minutes) and the concurrent -session count is capped at `max_sessions` (default 10000). A session's idle timer is reset by activity that touches it -(a GET, or a regular-request POST), and expired sessions are collected by a background reaper roughly once a minute, -so cleanup lags inactivity by up to that interval. At the cap, the transport first reclaims any already-expired slots -and then, if still full, rejects a new `initialize` with HTTP 503 (it does not evict an existing session). - -```ruby -# Tune the limits -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, session_idle_timeout: 900, max_sessions: 5000) - -# Opt out of expiry and/or the cap (not recommended on internet-facing deployments) -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, session_idle_timeout: nil, max_sessions: nil) -``` - -Stateless mode (`stateless: true`) retains no sessions, so neither limit applies to it. The same holds -for requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle), which never create a session; -their long-lived [`subscriptions/listen`](/server/subscriptions/) streams are bounded separately -by `max_listen_subscriptions:`. - -### Session Ownership - -`StreamableHTTPTransport` issues a random `SecureRandom.uuid` session ID and validates incoming requests by session -existence and idle timeout only. It does not bind a session to a user, because the transport never receives -an authenticated identity on its own. A caller that obtains a valid session ID could therefore act on that session, -so binding a session to a user is the deploying application's responsibility (the MCP spec frames this as a SHOULD). - -The primary control is the `session_request_validator`. It is called as `->(request, session_id) { true | false }` -on every non-`initialize` POST, GET, and DELETE against an existing session (including notification and response POSTs, -so a stolen session ID cannot, for example, POST `notifications/cancelled` against a victim's request). A falsy return -rejects the request with HTTP 403. Use it to compare the request's authenticated principal against the one recorded -when the session was created: - -```ruby -transport = MCP::Server::Transports::StreamableHTTPTransport.new( - server, - session_request_validator: ->(request, session_id) { owns_session?(request, session_id) }, -) -``` - -Without a validator the transport does not enforce ownership. As a limited defense in depth (not authentication), -it also records the `Origin` header at `initialize` and rejects a later request whose `Origin` differs, but only -when both are present - a non-browser client that omits `Origin` (e.g. `curl` or a script) is not stopped by this check. -Enforcing ownership against a determined attacker requires supplying the validator with an authenticated principal. - -Requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) carry no `Mcp-Session-Id` and touch no stored session, -so there is no session to steal, and neither the validator nor the recorded-`Origin` comparison runs for them -(the per-request `Origin` validation of the DNS rebinding protection above still applies); -on that path, authorization is enforced per request by the deploying application. - -### Request Size Limits - -`StreamableHTTPTransport` bounds how many bytes a single POST body may allocate, so a peer cannot exhaust memory -with one oversized message. A body larger than `max_request_bytes` (default 4 MiB) is rejected with HTTP 413, -and JSON nesting depth is capped. The 4 MiB default comfortably fits a typical JSON-RPC message (a 4 MiB JSON -string decodes to roughly 3 MiB of base64 payload) and matches the TypeScript SDK's 4 MB default; raise it only -if you exchange unusually large payloads: - -```ruby -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server, max_request_bytes: 8 * 1024 * 1024) -``` - -Unlike the deployment options above, these bounds apply to both lifecycles: -requests of the [modern lifecycle](/server/discover/#the-stateless-modern-lifecycle) are read through the same byte and nesting limits. diff --git a/docs/assets/css/just-the-docs-dark.scss b/docs/assets/css/just-the-docs-dark.scss deleted file mode 100644 index 20226a0..0000000 --- a/docs/assets/css/just-the-docs-dark.scss +++ /dev/null @@ -1,3 +0,0 @@ ---- ---- -{% include css/just-the-docs.scss.liquid color_scheme="ruby-dark" %} diff --git a/docs/assets/css/just-the-docs-light.scss b/docs/assets/css/just-the-docs-light.scss deleted file mode 100644 index c2a0250..0000000 --- a/docs/assets/css/just-the-docs-light.scss +++ /dev/null @@ -1,3 +0,0 @@ ---- ---- -{% include css/just-the-docs.scss.liquid color_scheme="ruby-light" %} diff --git a/docs/assets/images/icons/github.svg b/docs/assets/images/icons/github.svg deleted file mode 100644 index 75db234..0000000 --- a/docs/assets/images/icons/github.svg +++ /dev/null @@ -1,4 +0,0 @@ - - GitHub - - diff --git a/docs/assets/images/icons/theme-dark.svg b/docs/assets/images/icons/theme-dark.svg deleted file mode 100644 index 0571e5c..0000000 --- a/docs/assets/images/icons/theme-dark.svg +++ /dev/null @@ -1,3 +0,0 @@ - - - diff --git a/docs/assets/images/icons/theme-light.svg b/docs/assets/images/icons/theme-light.svg deleted file mode 100644 index e31928f..0000000 --- a/docs/assets/images/icons/theme-light.svg +++ /dev/null @@ -1,11 +0,0 @@ - - - - - - - - - - - diff --git a/docs/assets/images/icons/theme-system.svg b/docs/assets/images/icons/theme-system.svg deleted file mode 100644 index 77dd0d4..0000000 --- a/docs/assets/images/icons/theme-system.svg +++ /dev/null @@ -1,5 +0,0 @@ - - - - - diff --git a/docs/examples.md b/docs/examples.md deleted file mode 100644 index 819f4c1..0000000 --- a/docs/examples.md +++ /dev/null @@ -1,48 +0,0 @@ ---- -layout: default -title: Examples -nav_order: 3 -permalink: /examples/ ---- - -# Examples - -Runnable examples live in [`examples/`](https://github.com/modelcontextprotocol/ruby-sdk/tree/main/examples) in the repository. - -## Standalone Scripts - -- [`stdio_server.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/stdio_server.rb) - a stdio server for desktop applications and command-line tools -- [`stdio_client.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/stdio_client.rb) - a client that spawns the stdio server as a subprocess and exercises its tools, prompts, and resources -- [`http_server.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/http_server.rb) - a Rack-based Streamable HTTP server with session management and SSE support -- [`http_client.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/http_client.rb) - a client driving the HTTP server through all MCP protocol methods -- [`streamable_http_server.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb) - an SSE-focused server with tools that trigger notifications and progress updates -- [`streamable_http_client.rb`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_client.rb) - an interactive, menu-driven client for testing the SSE stream - -Each script is standalone and run from the repository root: - -```console -$ ruby examples/stdio_server.rb -``` - -See [`examples/README.md`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/README.md) for per-example usage and the requests each one demonstrates. - -## Rails Application - -[`examples/rails`](https://github.com/modelcontextprotocol/ruby-sdk/tree/main/examples/rails) is a complete, minimal -Rails application serving an MCP server over the Streamable HTTP transport. The server and transport are built once -at boot and mounted at `/mcp` in `config/routes.rb`; tools live in `app/tools/`, and a text resource is served through -a `resources_read_handler`. - -```console -$ cd examples/rails -$ bundle install -$ bundle exec puma --port 9292 -``` - -The MCP endpoint is then available at `http://localhost:9292/mcp`. See -[`examples/rails/README.md`](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/rails/README.md) -for a step-by-step cURL walkthrough of the session handshake and tool calls. - -The mount pattern this application uses is explained in [Rails (mount)](/server/transports/#rails-mount) -on the Transports page, alongside [Rails (controller)](/server/transports/#rails-controller), an alternative -that builds a server per request so tools and configuration can vary by request. diff --git a/docs/favicon.svg b/docs/favicon.svg deleted file mode 100644 index a280d7f..0000000 --- a/docs/favicon.svg +++ /dev/null @@ -1,11 +0,0 @@ - - - - - - - - - - - diff --git a/docs/index.md b/docs/index.md index ee275fc..305c3a1 100644 --- a/docs/index.md +++ b/docs/index.md @@ -1,131 +1,7 @@ --- -layout: default -title: Introduction -nav_order: 1 +# Empty Jekyll front matter to enable Liquid templating (see {{ ... }} below) --- -# MCP Ruby SDK - -The official Ruby SDK for the [Model Context Protocol](https://modelcontextprotocol.io/) (MCP), implementing both server and client functionality for JSON-RPC 2.0 based communication between LLM applications and context providers. - -## Features - -- Build [MCP servers](/server/) that expose tools, prompts, and resources to any MCP host -- Build [MCP clients](/client/) that connect to any MCP server, with automatic lifecycle negotiation and OAuth 2.1 authorization -- Speak every standard transport: stdio and Streamable HTTP (including SSE), with a Rails integration -- Cover the full protocol surface: server-to-client requests, multi round-trip requests, notifications, progress, logging, cancellation, completions, and pagination - -## Quick Start - -The following minimal programs show both sides of the protocol: a server that exposes a single tool, -and a client that spawns such a server and drives it over stdio. - -### MCP Server - -A minimal server defines a tool and serves it over the stdio transport: - -```ruby -require "mcp" - -# Create a simple tool -class ExampleTool < MCP::Tool - description "A simple example tool that echoes back its arguments" - input_schema( - properties: { - message: { type: "string" }, - }, - required: ["message"] - ) - - class << self - def call(message:, server_context:) - MCP::Tool::Response.new([{ - type: "text", - text: "Hello from example tool! Message: #{message}", - }]) - end - end -end - -# Set up the server -server = MCP::Server.new( - name: "example_server", - tools: [ExampleTool], -) - -# Create and start the transport -transport = MCP::Server::Transports::StdioTransport.new(server) -transport.open -``` - -Save the script as `server.rb`, run it, and send JSON-RPC requests via stdin: - -```console -$ ruby server.rb -{"jsonrpc":"2.0","id":"1","method":"ping"} -{"jsonrpc":"2.0","id":"2","method":"tools/list"} -{"jsonrpc":"2.0","id":"3","method":"tools/call","params":{"name":"example_tool","arguments":{"message":"Hello"}}} -``` - -The same server can also run over Streamable HTTP, including mounted inside a Rails application; -see [Server Transports](/server/transports/). - -### MCP Client - -A minimal client spawns a stdio server as a subprocess, connects, and lists and calls its tools: - -```ruby -stdio_transport = MCP::Client::Stdio.new( - command: "bundle", - args: ["exec", "ruby", "path/to/server.rb"], - env: { "API_KEY" => "my_secret_key" }, - read_timeout: 30 -) -client = MCP::Client.new(transport: stdio_transport) - -# Perform the MCP initialization handshake before sending any requests. -client.connect - -# List available tools. -tools = client.tools -tools.each do |tool| - puts "Tool: #{tool.name} - #{tool.description}" -end - -# Call a specific tool. -response = client.call_tool( - tool: tools.first, - arguments: { message: "Hello, world!" } -) - -# Close the transport when done. -stdio_transport.close -``` - -The same client can connect to Streamable HTTP servers with `MCP::Client::HTTP`; -see [Client Transports](/client/transports/). - -For comprehensive documentation, see: - -- [Installation](/installation/) - installing the gem and optional feature dependencies -- [Examples](/examples/) - runnable example scripts and a complete Rails application -- [Protocol Versions](/protocol-versions/) - supported versions, the era model, and client negotiation -- [Building Servers](server/) - transports, discovery, tools, prompts, resources, server-to-client requests, multi round-trip requests, notifications, protocol utilities, and configuration -- [Building Clients](client/) - transports, lifecycle negotiation, multi round-trip requests, and OAuth 2.1 authorization -- [Extensions](/extensions/) - capability extensions and MCP Apps - -## API Documentation - -Full API reference is hosted on [RubyDoc.info](https://rubydoc.info/gems/mcp). Select a version to view: - - - -## License - -This project is licensed under the Apache License 2.0 for new contributions, with existing code under MIT. See the [LICENSE](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/LICENSE) file for details. +{% for version in site.data.versions -%} +- [v{{ version }}](https://rubydoc.info/gems/mcp/{{ version }}) +{% endfor %} diff --git a/docs/installation.md b/docs/installation.md deleted file mode 100644 index 91aaee1..0000000 --- a/docs/installation.md +++ /dev/null @@ -1,53 +0,0 @@ ---- -layout: default -title: Installation -nav_order: 2 -permalink: /installation/ -redirect_from: - - /installation.html ---- - -# Installation - -Install the gem and any optional dependencies for the features you use. - -## Requirements - -Ruby 2.7.0 or later. - -## Installing the Gem - -Add this line to your application's Gemfile: - -```ruby -gem "mcp" -``` - -And then execute: - -```console -$ bundle install -``` - -Or install it yourself as: - -```console -$ gem install mcp -``` - -You may need to add additional dependencies depending on which features you wish to access. For example, the HTTP client transport requires the `faraday` gem: - -```ruby -gem "faraday", ">= 2.0" -``` - -Reading SSE (`text/event-stream`) responses needs `event_stream_parser` as well. -Whether a response is JSON or SSE is the server's choice, made for each response, and this SDK's own server picks SSE by default, -so a client written for arbitrary servers needs both gems: - -```ruby -gem "faraday", ">= 2.0" -gem "event_stream_parser", ">= 1.0" -``` - -The [Transports](/client/transports/#http-transport-layer) page describes the one setup where `faraday` alone is enough. diff --git a/docs/protocol-versions.md b/docs/protocol-versions.md deleted file mode 100644 index 54e5e53..0000000 --- a/docs/protocol-versions.md +++ /dev/null @@ -1,62 +0,0 @@ ---- -layout: default -title: Protocol Versions -nav_order: 4 -permalink: /protocol-versions/ ---- - -# Protocol Versions - -The SDK supports the following MCP protocol versions: - -| Version | Era | Notes | -|--------------|-----------|-------------------------------------------------------------------------------------------------| -| `2026-07-28` | Modern | Stateless lifecycle: no handshake, version carried on every request (SEP-2575) | -| `2025-11-25` | Handshake | The default handshake version; adds URL mode elicitation, enum schemas, and sampling tools | -| `2025-06-18` | Handshake | Adds elicitation, structured tool output, and OAuth resource servers; removes JSON-RPC batching | -| `2025-03-26` | Handshake | Adds Streamable HTTP, OAuth 2.1 authorization, tool annotations, and audio content | -| `2024-11-05` | Handshake | Initial protocol revision | - -## The Era Model - -Per the SEP-2575 era model, an era is a property of the protocol version itself: - -- **The modern version** (`2026-07-28`) has no handshake at all: clients discover the server through - [`server/discover`](/server/discover/), and every request carries its version in the `_meta` envelope, - validated per request. -- **Handshake versions** (`2025-11-25` and earlier) establish a session through the `initialize` handshake. - The server offers `2025-11-25` by default, and the version can be pinned with `MCP::Configuration.new(protocol_version:)`; - see [Server Protocol Version](/server/configuration/#server-protocol-version). - -Pinning the server's handshake version: - -```ruby -configuration = MCP::Configuration.new(protocol_version: "2025-06-18") -MCP::Server.new(name: "my_server", configuration: configuration) -``` - -The handshake never negotiates a modern version: a client asking `initialize` for `2026-07-28` is counter-offered -the latest handshake version, matching the TypeScript and Python SDKs. The bundled transports serve both eras -side by side with no configuration needed. - -## Client Negotiation - -`MCP::Client#connect` negotiates the lifecycle automatically by default: it probes `server/discover` and adopts -the modern lifecycle when the server serves it, falling back to the `initialize` handshake otherwise. -`connect(mode: :modern)`, `connect(mode: :legacy)`, and an explicit `protocol_version:` pin select a lifecycle -directly; see [Lifecycle](/client/lifecycle/). - -```ruby -client.connect # negotiate automatically (default) -client.connect(mode: :modern) # require the modern lifecycle -client.connect(mode: :legacy) # force the classic initialize handshake -client.connect(protocol_version: "2025-11-25") # pin the handshake version, no probe -``` - -## Deprecations - -The `2026-07-28` revision deprecates [Roots](/server/roots/), [Sampling](/server/sampling/), and -[Logging](/server/logging/) per SEP-2577; all three remain fully supported on the handshake versions. - -Check the [MCP specification](https://modelcontextprotocol.io/specification/versioning) to understand what each -protocol version includes. diff --git a/examples/README.md b/examples/README.md index af1828a..17de63b 100644 --- a/examples/README.md +++ b/examples/README.md @@ -4,7 +4,7 @@ This directory contains examples of how to use the Model Context Protocol (MCP) ## Available Examples -### 1. stdio Server (`stdio_server.rb`) +### 1. STDIO Server (`stdio_server.rb`) A simple server that communicates over standard input/output. This is useful for desktop applications and command-line tools. @@ -15,26 +15,7 @@ $ ruby examples/stdio_server.rb {"jsonrpc":"2.0","id":0,"method":"tools/list"} ``` -### 2. stdio Client (`stdio_client.rb`) - -A client that connects to the stdio server using the `MCP::Client::Stdio` transport. -This demonstrates how to use the SDK's built-in client classes to interact with a server subprocess. - -**Usage:** - -```console -$ ruby examples/stdio_client.rb -``` - -The client will automatically launch `stdio_server.rb` as a subprocess and demonstrate: - -- Performing the MCP initialization handshake via `client.connect` -- Listing and calling tools -- Listing prompts -- Listing and reading resources -- Transport cleanup on exit - -### 3. HTTP Server (`http_server.rb`) +### 2. HTTP Server (`http_server.rb`) A standalone HTTP server built with Rack that implements the MCP Streamable HTTP transport protocol. This demonstrates how to create a web-based MCP server with session management and Server-Sent Events (SSE) support. @@ -55,12 +36,12 @@ $ ruby examples/http_server.rb The server will start on `http://localhost:9292` and provide: - **Tools**: - - `example_tool` - adds two numbers + - `ExampleTool` - adds two numbers - `echo` - echoes back messages -- **Prompts**: `example_prompt` - echoes back arguments as a prompt +- **Prompts**: `ExamplePrompt` - echoes back arguments as a prompt - **Resources**: `test_resource` - returns example content -### 4. HTTP Client Example (`http_client.rb`) +### 3. HTTP Client Example (`http_client.rb`) A client that demonstrates how to interact with the HTTP server using all MCP protocol methods. @@ -86,7 +67,7 @@ The client will demonstrate: - Listing and reading resources - Session cleanup -### 5. Streamable HTTP Server (`streamable_http_server.rb`) +### 4. Streamable HTTP Server (`streamable_http_server.rb`) A specialized HTTP server designed to test and demonstrate Server-Sent Events (SSE) functionality in the MCP protocol. @@ -98,7 +79,7 @@ A specialized HTTP server designed to test and demonstrate Server-Sent Events (S **Available Tools:** -- `notification_tool` - Sends progress notifications over SSE, with optional delays +- `NotificationTool` - Send custom SSE notifications with optional delays - `echo` - Simple echo tool for basic testing **Usage:** @@ -109,7 +90,7 @@ $ ruby examples/streamable_http_server.rb The server will start on `http://localhost:9393` and provide detailed instructions for testing SSE functionality. -### 6. Streamable HTTP Client (`streamable_http_client.rb`) +### 5. Streamable HTTP Client (`streamable_http_client.rb`) An interactive client that connects to the SSE stream and provides a menu-driven interface for testing SSE functionality. @@ -124,15 +105,14 @@ An interactive client that connects to the SSE stream and provides a menu-driven 1. Start the SSE test server in one terminal: -```console -$ ruby examples/streamable_http_server.rb -``` + ```console + $ ruby examples/streamable_http_server.rb + ``` 2. Run the SSE test client in another terminal: - -```console -$ ruby examples/streamable_http_client.rb -``` + ```console + $ ruby examples/streamable_http_client.rb + ``` The client will: @@ -141,74 +121,6 @@ The client will: - Provide an interactive menu to trigger notifications - Display all received SSE events in real-time -### 7. Rails Server (`rails/`) - -A minimal Rails application that mounts `StreamableHTTPTransport` in its routes, following the "Rails (mount)" pattern from the top-level README. -It demonstrates class-based tools in `app/tools/` and a resource with a read handler. - -**Usage:** - -```console -$ cd examples/rails -$ bundle install -$ bundle exec puma --port 9292 -``` - -The MCP endpoint is available at `http://localhost:9292/mcp`. See [`rails/README.md`](rails/README.md) for a full curl-based walkthrough. - -### 8. Modern Lifecycle HTTP Server / Client (`modern_http_server.rb`, `modern_http_client.rb`) - -A server and client pair demonstrating the 2026-07-28 modern lifecycle (SEP-2575), which replaces the `initialize` handshake and per-session state with sessionless, self-contained requests. - -**Features:** - -- `server/discover` capability discovery before (or instead of) a handshake -- The per-request `_meta` envelope and `Mcp-Method` / `Mcp-Name` headers, stamped by the SDK automatically -- `resultType` stamping and SEP-2549 cache hints (`ttlMs`, `cacheScope`) on results -- A multi round-trip `deploy` tool (SEP-2322), resumed automatically by the client's elicitation handler -- The removal of legacy-only methods such as `ping` - -**Usage:** - -1. Start the server in one terminal: - -```console -$ ruby examples/modern_http_server.rb -``` - -2. Run the client in another terminal: - -```console -$ ruby examples/modern_http_client.rb -``` - -The same server still accepts the legacy `initialize` flow: the transport routes each request to the legacy or modern lifecycle by its `MCP-Protocol-Version` header. - -### Testing with MCP Inspector - -[MCP Inspector](https://modelcontextprotocol.io/docs/tools/inspector) is a browser-based tool for testing and debugging MCP servers. - -1. Start the server: - -```console -$ ruby examples/streamable_http_server.rb -``` - -2. Start Inspector in another terminal: - -```console -$ npx @modelcontextprotocol/inspector -``` - -3. Open `http://localhost:6274` in a browser: - -- Set Transport Type to "Streamable HTTP" -- Set URL to `http://localhost:9393` -- Disable the Authorization header toggle (the example server does not require authentication) -- Click "Connect" - -Once connected, you can list tools, call them, and see SSE notifications in the Inspector UI. - ### Testing SSE with cURL You can also test SSE functionality manually using cURL: @@ -217,78 +129,24 @@ You can also test SSE functionality manually using cURL: ```console SESSION_ID=$(curl -D - -s -o /dev/null http://localhost:9393 \ - -H "Accept: application/json, text/event-stream" \ - --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"curl-test","version":"1.0"}}}' | grep -i "Mcp-Session-Id:" | cut -d' ' -f2- | tr -d '\r') + --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"curl-test","version":"1.0"}}}' | grep -i "Mcp-Session-Id:" | cut -d' ' -f2- | tr -d '\r') ``` -2. Optionally connect the standalone SSE stream, which carries server-initiated messages that are not tied to a request (in another terminal): +2. Connect to SSE stream (in one terminal): ```console curl -i -N -H "Mcp-Session-Id: $SESSION_ID" http://localhost:9393 ``` -3. Call the notification tool. The `notifications/progress` events (requested via the `progressToken` in `_meta`) and the final response arrive as SSE events on the POST response itself: +3. Trigger notifications (in another terminal): ```console +# Send immediate notification curl -i http://localhost:9393 \ - -H "Accept: application/json, text/event-stream" \ -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","method":"tools/call","id":2,"params":{"name":"notification_tool","arguments":{"message":"Hello from cURL!","delay":0.5},"_meta":{"progressToken":"curl-progress"}}}' + --json '{"jsonrpc":"2.0","method":"tools/call","id":2,"params":{"name":"notification_tool","arguments":{"message":"Hello from cURL!"}}}' ``` -### Testing the modern lifecycle with cURL - -The modern lifecycle (2026-07-28, SEP-2575) is sessionless: there is no `initialize` handshake and no `Mcp-Session-Id`. Start `examples/modern_http_server.rb` and walk it manually: - -1. Probe capabilities with `server/discover`: - -```console -curl -s http://localhost:9494 \ - -H "Accept: application/json, text/event-stream" \ - --json '{"jsonrpc":"2.0","id":0,"method":"server/discover"}' -``` - -2. List tools (the `MCP-Protocol-Version` header selects the era, `Mcp-Method` mirrors the method, and `params._meta` carries the SEP-2575 envelope): - -```console -curl -s http://localhost:9494 \ - -H "Accept: application/json, text/event-stream" \ - -H "MCP-Protocol-Version: 2026-07-28" \ - -H "Mcp-Method: tools/list" \ - --json '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}' -``` - -3. Call a tool (name-bearing methods additionally mirror the name in the `Mcp-Name` header): - -```console -curl -s http://localhost:9494 \ - -H "Accept: application/json, text/event-stream" \ - -H "MCP-Protocol-Version: 2026-07-28" \ - -H "Mcp-Method: tools/call" \ - -H "Mcp-Name: greet" \ - --json '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"greet","arguments":{"name":"curl"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}' -``` - -4. Observe a multi round-trip result (SEP-2322), then resume it by echoing the `requestState` back together with the answer. Declaring the `elicitation` capability in the envelope is required before the server may embed elicitation requests: - -```console -curl -s http://localhost:9494 \ - -H "Accept: application/json, text/event-stream" \ - -H "MCP-Protocol-Version: 2026-07-28" \ - -H "Mcp-Method: tools/call" \ - -H "Mcp-Name: deploy" \ - --json '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"deploy","arguments":{"app":"storefront"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{"elicitation":{}}}}}' - -curl -s http://localhost:9494 \ - -H "Accept: application/json, text/event-stream" \ - -H "MCP-Protocol-Version: 2026-07-28" \ - -H "Mcp-Method: tools/call" \ - -H "Mcp-Name: deploy" \ - --json '{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"deploy","arguments":{"app":"storefront"},"inputResponses":{"environment":{"action":"accept","content":{"environment":"staging"}}},"requestState":"{\"app\":\"storefront\"}","_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{"elicitation":{}}}}}' -``` - -The same server still accepts the legacy flow from the previous sections, routed by the `MCP-Protocol-Version` header. - ## Streamable HTTP Transport Details ### Protocol Flow @@ -319,15 +177,13 @@ Initialize a session: ```console curl -i http://localhost:9292 \ - -H "Accept: application/json, text/event-stream" \ - --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' + --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' ``` List tools (using the session ID from initialization): ```console curl -i http://localhost:9292 \ - -H "Accept: application/json, text/event-stream" \ -H "Mcp-Session-Id: YOUR_SESSION_ID" \ --json '{"jsonrpc":"2.0","method":"tools/list","id":2}' ``` @@ -336,7 +192,6 @@ Call a tool: ```console curl -i http://localhost:9292 \ - -H "Accept: application/json, text/event-stream" \ -H "Mcp-Session-Id: YOUR_SESSION_ID" \ - --json '{"jsonrpc":"2.0","method":"tools/call","id":3,"params":{"name":"example_tool","arguments":{"a":5,"b":3}}}' + --json '{"jsonrpc":"2.0","method":"tools/call","id":3,"params":{"name":"ExampleTool","arguments":{"a":5,"b":3}}}' ``` diff --git a/examples/http_client.rb b/examples/http_client.rb index b61b563..3efbff9 100644 --- a/examples/http_client.rb +++ b/examples/http_client.rb @@ -4,7 +4,7 @@ require "net/http" require "json" require "uri" -# Simple HTTP client example for interacting with the MCP HTTP server. +# Simple HTTP client example for interacting with the MCP HTTP server class MCPHTTPClient def initialize(base_url = "http://localhost:9292") @base_url = base_url @@ -30,51 +30,19 @@ class MCPHTTPClient response = http.request(request) - # Store session ID if provided. + # Store session ID if provided if response["Mcp-Session-Id"] @session_id = response["Mcp-Session-Id"] puts "Session ID: #{@session_id}" end - parse_response_body(response) - end - - # In the transport's default SSE mode, POST responses on an established session arrive as - # a Server-Sent Events stream whose `data:` line carries the JSON-RPC response; unwrap it - # before parsing. - def parse_response_body(response) - body = response.body - - if response["Content-Type"]&.start_with?("text/event-stream") - data_lines = body.lines.select { |line| line.start_with?("data:") } - body = data_lines.map { |line| line.sub(/\Adata:\s*/, "") }.join - end - - JSON.parse(body) - end - - def send_notification(method, params = nil) - uri = URI(@base_url) - http = Net::HTTP.new(uri.host, uri.port) - - request = Net::HTTP::Post.new(uri.path.empty? ? "/" : uri.path) - request["Content-Type"] = "application/json" - request["Mcp-Session-Id"] = @session_id if @session_id - - # Notifications carry no `id` and receive no JSON-RPC response body. - request.body = { - jsonrpc: "2.0", - method: method, - params: params, - }.compact.to_json - - http.request(request) + JSON.parse(response.body) end def initialize_session puts "=== Initializing session ===" result = send_request("initialize", { - protocolVersion: "2025-11-25", + protocolVersion: "2024-11-05", capabilities: {}, clientInfo: { name: "example_client", @@ -86,14 +54,6 @@ class MCPHTTPClient result end - def notify_initialized - puts "=== Sending notifications/initialized ===" - response = send_notification("notifications/initialized") - puts "Response status: #{response.code} #{response.message}" - - response - end - def ping puts "=== Sending ping ===" result = send_request("ping") @@ -177,7 +137,8 @@ class MCPHTTPClient end end -def main +# Main script +if __FILE__ == $PROGRAM_NAME puts <<~MESSAGE MCP HTTP Client Example Make sure the HTTP server is running (ruby examples/http_server.rb) @@ -187,42 +148,37 @@ def main client = MCPHTTPClient.new begin - # Initialize session. + # Initialize session client.initialize_session - # Complete the handshake. - client.notify_initialized - - # Test ping. + # Test ping client.ping - # List available tools. + # List available tools client.list_tools - # Call the example_tool (note: snake_case name). + # Call the example_tool (note: snake_case name) client.call_tool("example_tool", { a: 5, b: 3 }) - # Call the echo tool. + # Call the echo tool client.call_tool("echo", { message: "Hello from client!" }) - # List prompts. + # List prompts client.list_prompts - # Get a prompt (note: snake_case name). + # Get a prompt (note: snake_case name) client.get_prompt("example_prompt", { message: "This is a test message" }) - # List resources. + # List resources client.list_resources - # Read a resource (the URI registered by http_server.rb). - client.read_resource("https://test_resource.invalid") + # Read a resource + client.read_resource("test_resource") rescue => e puts "Error: #{e.message}" puts e.backtrace ensure - # Clean up session. + # Clean up session client.close_session end end - -main diff --git a/examples/http_server.rb b/examples/http_server.rb index 33d8d80..df4189c 100644 --- a/examples/http_server.rb +++ b/examples/http_server.rb @@ -2,7 +2,6 @@ $LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) require "mcp" -require "rack/cors" require "rackup" require "json" require "logger" @@ -56,7 +55,6 @@ end # Set up the server server = MCP::Server.new( name: "example_http_server", - version: "1.0.0", tools: [ExampleTool], prompts: [ExamplePrompt], resources: [ @@ -95,74 +93,62 @@ end # Create the Streamable HTTP transport transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) +server.transport = transport -# Rack middleware for MCP-specific request/response logging. -class McpRequestLogger - def initialize(app) - @app = app - @logger = Logger.new($stdout) - @logger.formatter = proc { |_severity, _datetime, _progname, msg| "[MCP] #{msg}\n" } - end - - def call(env) - if env["REQUEST_METHOD"] == "POST" - body = env["rack.input"].read - env["rack.input"].rewind - - begin - parsed = JSON.parse(body) - - @logger.info("Request: #{parsed["method"]} (id: #{parsed["id"]})") - @logger.debug("Request body: #{JSON.pretty_generate(parsed)}") - rescue JSON::ParserError - @logger.warn("Request body (raw): #{body}") - end - end - - status, headers, response_body = @app.call(env) - - if response_body.is_a?(Array) && !response_body.empty? && response_body.first - begin - parsed = JSON.parse(response_body.first) - - if parsed["error"] - @logger.error("Response error: #{parsed["error"]["message"]}") - else - @logger.info("Response: #{parsed["result"] ? "success" : "empty"} (id: #{parsed["id"]})") - end - @logger.debug("Response body: #{JSON.pretty_generate(parsed)}") - rescue JSON::ParserError - @logger.warn("Response body (raw): #{response_body}") - end - end - - [status, headers, response_body] - end +# Create a logger for MCP-specific logging +mcp_logger = Logger.new($stdout) +mcp_logger.formatter = proc do |_severity, _datetime, _progname, msg| + "[MCP] #{msg}\n" end -# Build the Rack application with middleware. -# `StreamableHTTPTransport` responds to `call(env)`, so it can be used directly as a Rack app. -rack_app = Rack::Builder.new do - # Enable CORS to allow browser-based MCP clients (e.g., MCP Inspector) - # WARNING: origins("*") allows all origins. Restrict this in production. - use(Rack::Cors) do - allow do - origins("*") - resource( - "*", - headers: :any, - methods: [:get, :post, :delete, :options], - expose: ["Mcp-Session-Id"], - ) +# Create a Rack application with logging +app = proc do |env| + request = Rack::Request.new(env) + + # Log MCP-specific details for POST requests + if request.post? + body = request.body.read + request.body.rewind + begin + parsed_body = JSON.parse(body) + mcp_logger.info("Request: #{parsed_body["method"]} (id: #{parsed_body["id"]})") + mcp_logger.debug("Request body: #{JSON.pretty_generate(parsed_body)}") + rescue JSON::ParserError + mcp_logger.warn("Request body (raw): #{body}") end end + # Handle the request + response = transport.handle_request(request) + + # Log the MCP response details + _, _, body = response + if body.is_a?(Array) && !body.empty? && body.first + begin + parsed_response = JSON.parse(body.first) + if parsed_response["error"] + mcp_logger.error("Response error: #{parsed_response["error"]["message"]}") + else + mcp_logger.info("Response: #{parsed_response["result"] ? "success" : "empty"} (id: #{parsed_response["id"]})") + end + mcp_logger.debug("Response body: #{JSON.pretty_generate(parsed_response)}") + rescue JSON::ParserError + mcp_logger.warn("Response body (raw): #{body}") + end + end + + response +end + +# Wrap the app with Rack middleware +rack_app = Rack::Builder.new do # Use CommonLogger for standard HTTP request logging use(Rack::CommonLogger, Logger.new($stdout)) - use(Rack::ShowExceptions) - use(McpRequestLogger) - run(transport) + # Add other useful middleware + use(Rack::ShowExceptions) + + run(app) end # Start the server @@ -170,9 +156,7 @@ puts <<~MESSAGE Starting MCP HTTP server on http://localhost:9292 Use POST requests to initialize and send JSON-RPC commands Example initialization: - curl -i http://localhost:9292 \\ - -H "Accept: application/json, text/event-stream" \\ - --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' + curl -i http://localhost:9292 --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}' The server will return a session ID in the Mcp-Session-Id header. Use this session ID for subsequent requests. diff --git a/examples/modern_http_client.rb b/examples/modern_http_client.rb deleted file mode 100644 index ca2cd1f..0000000 --- a/examples/modern_http_client.rb +++ /dev/null @@ -1,133 +0,0 @@ -# frozen_string_literal: true - -$LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) -require "mcp" -require "json" - -# Client example for the 2026-07-28 modern lifecycle (SEP-2575), which replaces the `initialize` handshake -# and per-session state with sessionless, self-contained requests. -class MCPModernHTTPClient - def initialize(base_url = "http://localhost:9494") - @transport = MCP::Client::HTTP.new(url: base_url) - @client = MCP::Client.new(transport: @transport) - end - - # `server/discover` (SEP-2575) is sessionless capability discovery that works before, or instead of, `connect`. - def discover - puts "=== Discovering server capabilities (server/discover) ===" - result = @client.discover - puts <<~MESSAGE - Supported versions: #{result.supported_versions.inspect} - Server: #{result.server_info} - Cache hints: ttlMs=#{result.ttl_ms}, cacheScope=#{result.cache_scope} (SEP-2549) - Instructions: #{result.instructions} - MESSAGE - - result - end - - # The handler answers `elicitation/create` requests embedded in SEP-2322 `input_required` results; once registered, - # `call_tool` resumes those results automatically. - # Register it before `connect` so the connection never needs a server-to-client route. - def register_elicitation_handler - @client.on_elicitation do |params| - puts " Server asked: #{params["message"]}" - - { action: "accept", content: MCP::Client::Elicitation.apply_defaults(params["requestedSchema"]) } - end - end - - # `mode: :modern` requires the modern lifecycle and fails on legacy-only servers; - # the default `:auto` probes `server/discover` first and falls back to the legacy `initialize` handshake. - # The `elicitation` capability must be declared before the server may embed elicitation requests. - def connect - puts "=== Adopting the modern lifecycle ===" - result = @client.connect( - client_info: { name: "modern-http-client", version: "1.0" }, - capabilities: { elicitation: {} }, - mode: :modern, - ) - puts <<~MESSAGE - Modern connection: #{@transport.modern?} - Protocol version: #{@client.protocol_version} - MESSAGE - - result - end - - # Modern requests are self-contained: the SDK stamps the `_meta` envelope (protocol version, - # client info, capabilities) and the Mcp-Method and Mcp-Name headers on every request automatically. - def list_tools - puts "=== Listing tools ===" - page = @client.list_tools - page.tools.each { |tool| puts " - #{tool.name}: #{tool.description}" } - puts "Cache hints: ttlMs=#{page.ttl_ms}, cacheScope=#{page.cache_scope}" - - page - end - - def call_tool(name, arguments) - puts "=== Calling tool: #{name} ===" - response = @client.call_tool(name: name, arguments: arguments) - puts <<~MESSAGE - resultType: #{response.dig("result", "resultType")} - Response: #{response.dig("result", "content", 0, "text")} - MESSAGE - - response - end - - # The modern lifecycle removed `initialize`, `ping`, `logging/setLevel`, and resource subscriptions (SEP-2575); - # calling one is an error. - def ping - puts "=== Calling removed method: ping ===" - @client.ping - rescue MCP::Client::RequestHandlerError => e - puts "ping was removed by the modern lifecycle (SEP-2575): #{e.message}" - end - - def close - # No session exists on a modern connection; this only clears local state. - @transport.close - end -end - -puts <<~MESSAGE - MCP Modern Lifecycle Client (2026-07-28) - Make sure the server is running (ruby examples/modern_http_server.rb) - #{"=" * 60} -MESSAGE - -client = MCPModernHTTPClient.new - -begin - # Probe the server before adopting a lifecycle. - client.discover - - # Answer the elicitation requests the server embeds in its results. - client.register_elicitation_handler - - # Adopt the modern lifecycle. - client.connect - - # List available tools. - client.list_tools - - # Call a plain single round-trip tool. - client.call_tool("greet", { name: "MCP" }) - - # Call a multi round-trip tool (SEP-2322): the driver fulfills the embedded elicitation via the handler registered above - # and re-issues the call with `inputResponses` plus the echoed `requestState`. Without a handler, `call_tool` raises - # `MCP::Client::InputRequiredError` for manual driving via the `input_responses:` / `request_state:` keywords. - client.call_tool("deploy", { app: "storefront" }) - - # Call a method the modern lifecycle removed. - client.ping -rescue => e - puts <<~MESSAGE - Error: #{e.message} - #{e.backtrace.join("\n")} - MESSAGE -ensure - client.close -end diff --git a/examples/modern_http_server.rb b/examples/modern_http_server.rb deleted file mode 100644 index b21c35d..0000000 --- a/examples/modern_http_server.rb +++ /dev/null @@ -1,126 +0,0 @@ -# frozen_string_literal: true - -$LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) -require "mcp" -require "rackup" -require "json" -require "logger" - -# Example server for the 2026-07-28 modern lifecycle (SEP-2575). -# -# The modern lifecycle is sessionless: there is no `initialize` handshake and no `Mcp-Session-Id`. -# Clients probe the server with `server/discover` and then send self-contained requests that carry -# a `_meta` envelope (protocol version, client info, capabilities) plus `MCP-Protocol-Version` / `Mcp-Method` headers. -# -# The same server still accepts the legacy `initialize` flow: the transport routes each request to -# the legacy or modern lifecycle by its `MCP-Protocol-Version` header, so no constructor flag is needed. -server = MCP::Server.new( - name: "modern_lifecycle_server", - version: "1.0.0", - instructions: "Example server demonstrating the 2026-07-28 modern lifecycle.", - # SEP-2549 cache hints, advertised in `server/discover` and stamped on cacheable results. - # The defaults are 0 / "private"; non-default values are used here so they are visible - # in the example output. - ttl_ms: 60_000, - cache_scope: "public", -) - -server.define_tool( - name: "greet", - description: "Greets a name; a plain single round-trip tool", - input_schema: { properties: { name: { type: "string" } }, required: ["name"] }, -) do |name:| - MCP::Tool::Response.new([{ type: "text", text: "Hello, #{name}!" }]) -end - -# A multi round-trip tool (SEP-2322). The first round returns an `input_required` result asking -# the client to answer an embedded `elicitation/create` request; the client re-issues the call with -# `inputResponses` plus the echoed opaque `requestState`, and the handler re-runs from the start -# and reads the answer via `server_context`. -# Over a legacy connection the default `input_required_legacy_shim` fulfills the same result through -# a real server-to-client elicitation request instead. -server.define_tool( - name: "deploy", - description: "Deploys an app; asks which environment via a multi round-trip elicitation (SEP-2322)", - input_schema: { properties: { app: { type: "string" } }, required: ["app"] }, -) do |app:, server_context:| - answer = server_context.input_response("environment") - - if answer.nil? - MCP::Server::InputRequiredResult.new( - input_requests: { - "environment" => { - method: "elicitation/create", - params: { - message: "Which environment should #{app} deploy to?", - requestedSchema: { - type: "object", - properties: { - environment: { type: "string", title: "Environment", default: "staging" }, - }, - required: ["environment"], - }, - }, - }, - }, - request_state: JSON.generate(app: app), - ) - else - # Transports parse JSON with `symbolize_names: true`, so answers normally arrive symbol-keyed; - # the string fallback covers custom transports. - action = answer[:action] || answer["action"] - - if action == "accept" - environment = answer.dig(:content, :environment) || answer.dig("content", "environment") - MCP::Tool::Response.new([{ type: "text", text: "Deployed #{app} to #{environment}" }]) - else - MCP::Tool::Response.new([{ type: "text", text: "Deployment of #{app} was cancelled (#{action})" }]) - end - end -end - -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - -# `StreamableHTTPTransport` responds to `call(env)`, so it can be used directly as a Rack app. -# See http_server.rb for a CORS setup for browser-based clients. -rack_app = Rack::Builder.new do - use(Rack::CommonLogger, Logger.new($stdout)) - use(Rack::ShowExceptions) - - run(transport) -end - -puts <<~MESSAGE - === MCP Modern Lifecycle Server (2026-07-28) === - - Starting server on http://localhost:9494 - - Run the SDK client against it: - ruby examples/modern_http_client.rb - - Or walk the modern lifecycle with cURL: - - 1. Probe capabilities (sessionless, works without any protocol headers): - curl -s http://localhost:9494 \\ - -H "Accept: application/json, text/event-stream" \\ - --json '{"jsonrpc":"2.0","id":0,"method":"server/discover"}' - - 2. Modern tools/list (the MCP-Protocol-Version header selects the era, the - Mcp-Method header mirrors the method, and params._meta carries the - SEP-2575 envelope): - curl -s http://localhost:9494 \\ - -H "Accept: application/json, text/event-stream" \\ - -H "MCP-Protocol-Version: 2026-07-28" -H "Mcp-Method: tools/list" \\ - --json '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}' - - 3. Modern tools/call (name-bearing methods additionally mirror the name in - the Mcp-Name header; no Mcp-Session-Id is ever sent): - curl -s http://localhost:9494 \\ - -H "Accept: application/json, text/event-stream" \\ - -H "MCP-Protocol-Version: 2026-07-28" -H "Mcp-Method: tools/call" -H "Mcp-Name: greet" \\ - --json '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"greet","arguments":{"name":"curl"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}' - - Press Ctrl+C to stop the server -MESSAGE - -Rackup::Handler.get("puma").run(rack_app, Port: 9494, Host: "localhost") diff --git a/examples/rails/.gitignore b/examples/rails/.gitignore deleted file mode 100644 index 4910c63..0000000 --- a/examples/rails/.gitignore +++ /dev/null @@ -1,3 +0,0 @@ -/Gemfile.lock -/log/ -/tmp/ diff --git a/examples/rails/Gemfile b/examples/rails/Gemfile deleted file mode 100644 index a1494d8..0000000 --- a/examples/rails/Gemfile +++ /dev/null @@ -1,7 +0,0 @@ -# frozen_string_literal: true - -source "https://rubygems.org" - -gem "mcp", path: "../.." -gem "puma" -gem "rails", "~> 8.0" diff --git a/examples/rails/README.md b/examples/rails/README.md deleted file mode 100644 index eaee531..0000000 --- a/examples/rails/README.md +++ /dev/null @@ -1,116 +0,0 @@ -# Rails Example MCP Server - -A minimal Rails application that serves an MCP server over the Streamable HTTP transport, -following the "Rails (mount)" pattern from the [top-level README](../../README.md). - -The application provides: - -- `add_tool` tool (`app/tools/add_tool.rb`) - adds two numbers, demonstrates `input_schema` -- `greeting_tool` tool (`app/tools/greeting_tool.rb`) - greets a name, demonstrates `annotations` and `server_context` -- `example://rails/readme` resource - a text resource served via `resources_read_handler` - -The MCP server and transport are built once at boot in `config/routes.rb`, where the transport is mounted at `/mcp`. - -## Requirements - -- Ruby >= 3.2 (required by Rails 8; the `mcp` gem itself supports older Rubies) -- curl >= 7.82 (for the `--json` flag used below) - -## Running - -```console -$ cd examples/rails -$ bundle install -$ bundle exec puma --port 9292 -``` - -The MCP endpoint is now available at `http://localhost:9292/mcp`. - -## Testing with cURL - -POST requests must include an `Accept` header that allows both `application/json` and `text/event-stream`, -per the MCP Streamable HTTP transport spec. Responses arrive as SSE `data:` lines. - -1. Initialize a session and capture the session ID: - -```console -SESSION_ID=$(curl -s -D - -o /dev/null http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - --json '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"curl","version":"1.0"}}}' \ - | grep -i "^mcp-session-id:" | cut -d' ' -f2 | tr -d '\r') -``` - -2. Complete the handshake (expect `202 Accepted`): - -```console -curl -i http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","method":"notifications/initialized"}' -``` - -3. List and call tools: - -```console -curl http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","id":2,"method":"tools/list"}' - -curl http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"add_tool","arguments":{"a":5,"b":3}}}' - -curl http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"greeting_tool","arguments":{"name":"Rails"}}}' -``` - -4. List and read the resource: - -```console -curl http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","id":5,"method":"resources/list"}' - -curl http://localhost:9292/mcp \ - -H "Accept: application/json, text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" \ - --json '{"jsonrpc":"2.0","id":6,"method":"resources/read","params":{"uri":"example://rails/readme"}}' -``` - -5. Optionally, open the standalone SSE stream for server-to-client messages - (in another terminal): - -```console -curl -N http://localhost:9292/mcp \ - -H "Accept: text/event-stream" \ - -H "Mcp-Session-Id: $SESSION_ID" -``` - -6. End the session: - -```console -curl -i -X DELETE http://localhost:9292/mcp -H "Mcp-Session-Id: $SESSION_ID" -``` - -## Testing with MCP Inspector - -Start [MCP Inspector](https://modelcontextprotocol.io/docs/tools/inspector) with `npx @modelcontextprotocol/inspector`, -set Transport Type to "Streamable HTTP", and connect to `http://localhost:9292/mcp`. - -## Notes - -- `StreamableHTTPTransport` keeps session and SSE state in memory, so it must run in a single process. - Puma runs in single mode (`workers 0`) by default; do not enable clustered mode for this app. - When running multiple instances behind a load balancer, use sticky sessions keyed on the `Mcp-Session-Id` header, - or pass `stateless: true` to the transport. -- The server is built once at boot in `config/routes.rb`, so code reloading is disabled - (`config.enable_reloading = false` in `config/application.rb`). - Restart the server after changing tool or resource code. Note that tool classes cannot be referenced from - `config/initializers` because Zeitwerk has not set up autoloading at that point; routes load late enough that they can. -- For a per-request server with request-specific tools or context, see the "Rails (controller)" section in the top-level README, - which uses `stateless: true` and `transport.handle_request(request)` inside a controller action. diff --git a/examples/rails/app/tools/add_tool.rb b/examples/rails/app/tools/add_tool.rb deleted file mode 100644 index b3bf506..0000000 --- a/examples/rails/app/tools/add_tool.rb +++ /dev/null @@ -1,22 +0,0 @@ -# frozen_string_literal: true - -class AddTool < MCP::Tool - title "Add Tool" - description "A simple example tool that adds two numbers" - input_schema( - properties: { - a: { type: "number" }, - b: { type: "number" }, - }, - required: ["a", "b"], - ) - - class << self - def call(a:, b:) - MCP::Tool::Response.new([{ - type: "text", - text: "The sum of #{a} and #{b} is #{a + b}", - }]) - end - end -end diff --git a/examples/rails/app/tools/greeting_tool.rb b/examples/rails/app/tools/greeting_tool.rb deleted file mode 100644 index 00c8c3f..0000000 --- a/examples/rails/app/tools/greeting_tool.rb +++ /dev/null @@ -1,27 +0,0 @@ -# frozen_string_literal: true - -class GreetingTool < MCP::Tool - title "Greeting Tool" - description "Greets the given name and reports which app served the request" - input_schema( - properties: { - name: { type: "string" }, - }, - required: ["name"], - ) - annotations( - destructive_hint: false, - idempotent_hint: true, - open_world_hint: false, - read_only_hint: true, - ) - - class << self - def call(name:, server_context:) - MCP::Tool::Response.new([{ - type: "text", - text: "Hello, #{name}! (served by #{server_context[:app_name]})", - }]) - end - end -end diff --git a/examples/rails/config.ru b/examples/rails/config.ru deleted file mode 100644 index 14f9aab..0000000 --- a/examples/rails/config.ru +++ /dev/null @@ -1,5 +0,0 @@ -# frozen_string_literal: true - -require_relative "config/environment" - -run(Rails.application) diff --git a/examples/rails/config/application.rb b/examples/rails/config/application.rb deleted file mode 100644 index a61ce76..0000000 --- a/examples/rails/config/application.rb +++ /dev/null @@ -1,27 +0,0 @@ -# frozen_string_literal: true - -ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__) - -require "bundler/setup" - -require "rails" -require "action_controller/railtie" - -require "mcp" - -module McpRailsExample - class Application < Rails::Application - config.load_defaults(8.0) - - # This example has no views, assets, or database. - config.api_only = true - - # The MCP server is built once at boot (config/routes.rb) and holds references to the tool classes in app/tools, - # so code reloading is disabled; restart the server after changing tool or resource code. - # A reloading app would need `config.to_prepare` and a way to swap the transport's server instead. - config.enable_reloading = false - config.eager_load = true - - config.logger = ActiveSupport::Logger.new($stdout) - end -end diff --git a/examples/rails/config/environment.rb b/examples/rails/config/environment.rb deleted file mode 100644 index e8173e0..0000000 --- a/examples/rails/config/environment.rb +++ /dev/null @@ -1,5 +0,0 @@ -# frozen_string_literal: true - -require_relative "application" - -Rails.application.initialize! diff --git a/examples/rails/config/routes.rb b/examples/rails/config/routes.rb deleted file mode 100644 index 76f3c27..0000000 --- a/examples/rails/config/routes.rb +++ /dev/null @@ -1,46 +0,0 @@ -# frozen_string_literal: true - -# The MCP server and its Streamable HTTP transport are built here, once at boot, -# following the "Rails (mount)" pattern from the top-level README. -# Routes are loaded after the application initializes, so the tool classes in app/tools -# are available at this point (they are not yet available in config/initializers, -# where Zeitwerk has not set up autoloading). -# -# The transport keeps session and SSE state in memory, so run a single server process -# (e.g., Puma with `workers 0`, which is the rackup default). -# See the top-level README for multi-instance and stateless deployment notes. -server = MCP::Server.new( - name: "rails_example_server", - title: "Rails Example Server", - version: "1.0.0", - tools: [AddTool, GreetingTool], - resources: [ - MCP::Resource.new( - uri: "example://rails/readme", - name: "readme", - title: "Example README", - description: "Describes this Rails example MCP server", - mime_type: "text/plain", - ), - ], - server_context: { app_name: "mcp_rails_example" }, -) - -server.resources_read_handler do |params| - [ - { - uri: params[:uri], - mimeType: "text/plain", - text: "This resource is served by the Rails example MCP server (Rails #{Rails.version}).", - }, - ] -end - -transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - -Rails.application.routes.draw do - # `StreamableHTTPTransport` is a Rack app, so it can be mounted directly. - # `mount` directs all HTTP methods on /mcp to the transport, which internally dispatches POST (JSON-RPC messages), - # GET (SSE stream), and DELETE (session termination) per the MCP Streamable HTTP transport spec. - mount(transport => "/mcp") -end diff --git a/examples/stdio_client.rb b/examples/stdio_client.rb deleted file mode 100644 index 60b2067..0000000 --- a/examples/stdio_client.rb +++ /dev/null @@ -1,61 +0,0 @@ -# frozen_string_literal: true - -$LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) -require "mcp" -require "json" - -# Simple stdio client example that connects to the stdio_server.rb example -# Usage: ruby examples/stdio_client.rb - -server_script = File.expand_path("stdio_server.rb", __dir__) - -transport = MCP::Client::Stdio.new(command: "ruby", args: [server_script]) -client = MCP::Client.new(transport: transport) - -begin - # Perform the MCP initialization handshake before sending any requests. - client.connect - - # List available tools - puts "=== Listing tools ===" - tools = client.tools - tools.each do |tool| - puts " Tool: #{tool.name} - #{tool.description}" - end - - # Call the example_tool (adds two numbers) - puts "\n=== Calling tool: example_tool ===" - tool = tools.find { |t| t.name == "example_tool" } - response = client.call_tool(tool: tool, arguments: { a: 5, b: 3 }) - puts " Response: #{JSON.pretty_generate(response.dig("result", "content"))}" - - # Call the echo tool - puts "\n=== Calling tool: echo ===" - tool = tools.find { |t| t.name == "echo" } - response = client.call_tool(tool: tool, arguments: { message: "Hello from stdio client!" }) - puts " Response: #{JSON.pretty_generate(response.dig("result", "content"))}" - - # List prompts - puts "\n=== Listing prompts ===" - prompts = client.prompts - prompts.each do |prompt| - puts " Prompt: #{prompt["name"]} - #{prompt["description"]}" - end - - # List resources - puts "\n=== Listing resources ===" - resources = client.resources - resources.each do |resource| - puts " Resource: #{resource["name"]} (#{resource["uri"]})" - end - - # Read a resource - puts "\n=== Reading resource: https://test_resource.invalid ===" - contents = client.read_resource(uri: "https://test_resource.invalid") - puts " Response: #{JSON.pretty_generate(contents)}" -rescue => e - puts "Error: #{e.message}" - puts e.backtrace.first(5).join("\n") -ensure - transport.close -end diff --git a/examples/streamable_http_client.rb b/examples/streamable_http_client.rb index ab7aeed..b3a7477 100644 --- a/examples/streamable_http_client.rb +++ b/examples/streamable_http_client.rb @@ -1,28 +1,49 @@ # frozen_string_literal: true -$LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) -require "mcp" require "net/http" require "uri" require "json" require "logger" -require "event_stream_parser" -SERVER_URL = "http://localhost:9393" - -def create_logger - logger = Logger.new($stdout) - logger.formatter = proc do |severity, datetime, _progname, msg| - "[CLIENT] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n" - end - logger +# Logger for client operations +logger = Logger.new($stdout) +logger.formatter = proc do |severity, datetime, _progname, msg| + "[CLIENT] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n" end -# MCP::Client::HTTP opens the optional GET SSE stream itself once a server-request handler -# (e.g. `client.on_elicitation`) is registered. This example instead opens the stream with -# raw `Net::HTTP` to show the SSE wire format. The GET stream carries server-initiated messages -# that are not tied to a client request; request-scoped notifications such as progress arrive on -# the POST's own SSE response stream (see `stream_tool_call` below). +# Server configuration +SERVER_URL = "http://localhost:9393/mcp" +PROTOCOL_VERSION = "2024-11-05" + +# Helper method to make JSON-RPC requests +def make_request(session_id, method, params = {}, id = nil) + uri = URI(SERVER_URL) + http = Net::HTTP.new(uri.host, uri.port) + + request = Net::HTTP::Post.new(uri) + request["Content-Type"] = "application/json" + request["Mcp-Session-Id"] = session_id if session_id + + body = { + jsonrpc: "2.0", + method: method, + params: params, + id: id || SecureRandom.uuid, + } + + request.body = body.to_json + response = http.request(request) + + { + status: response.code, + headers: response.to_hash, + body: JSON.parse(response.body), + } +rescue => e + { error: e.message } +end + +# Connect to SSE stream def connect_sse(session_id, logger) uri = URI(SERVER_URL) @@ -38,13 +59,17 @@ def connect_sse(session_id, logger) if response.code == "200" logger.info("SSE stream connected successfully") - parser = EventStreamParser::Parser.new response.read_body do |chunk| - parser.feed(chunk) do |type, data, _id| - if type.empty? - logger.info("SSE event: #{data}") - else - logger.info("SSE event (#{type}): #{data}") + chunk.split("\n").each do |line| + if line.start_with?("data: ") + data = line[6..-1] + begin + logger.info("SSE data: #{data}") + rescue JSON::ParserError + logger.debug("Non-JSON SSE data: #{data}") + end + elsif line.start_with?(": ") + logger.debug("SSE keepalive received: #{line}") end end end @@ -54,172 +79,125 @@ def connect_sse(session_id, logger) end end rescue Interrupt - logger.info("SSE connection interrupted") + logger.info("SSE connection interrupted by user") rescue => e logger.error("SSE connection error: #{e.message}") end -def print_response(response) - if response.nil? - puts "Response accepted; watch the SSE stream for the server response." - else - puts "Response: #{JSON.pretty_generate(response)}" - end -end - -# Calls a tool with a raw streaming POST so each SSE event on the response stream is printed as -# it arrives: the `notifications/progress` events requested via `_meta.progressToken`, -# then the final JSON-RPC response. `MCP::Client#call_tool` reads the same stream but consumes -# the progress notifications internally, so the raw request makes them visible here. -def stream_tool_call(session_id, request_id, name:, arguments:, logger:) - uri = URI(SERVER_URL) - - body = { - jsonrpc: "2.0", - id: request_id, - method: "tools/call", - params: { - name: name, - arguments: arguments, - _meta: { progressToken: "streamable-http-client" }, - }, - } - - Net::HTTP.start(uri.host, uri.port) do |http| - request = Net::HTTP::Post.new(uri) - request["Content-Type"] = "application/json" - request["Accept"] = "application/json, text/event-stream" - request["Mcp-Session-Id"] = session_id - request.body = JSON.generate(body) - - http.request(request) do |response| - parser = EventStreamParser::Parser.new - response.read_body do |chunk| - parser.feed(chunk) do |_type, data, _id| - logger.info("SSE event: #{data}") - end - end - end - end -end - +# Main client flow def main - logger = create_logger + logger = Logger.new($stdout) + logger.formatter = proc do |severity, datetime, _progname, msg| + "[CLIENT] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n" + end - puts <<~MESSAGE - MCP Streamable HTTP Client - Make sure the server is running (ruby examples/streamable_http_server.rb) - #{"=" * 60} - MESSAGE + puts "=== MCP SSE Test Client ===" - http_transport = MCP::Client::HTTP.new(url: SERVER_URL) - client = MCP::Client.new(transport: http_transport) - sse_thread = nil - raw_request_id = 0 + # Step 1: Initialize session + logger.info("Initializing session...") - begin - puts "=== Initializing session ===" + init_response = make_request( + nil, + "initialize", + { + protocolVersion: PROTOCOL_VERSION, + capabilities: {}, + clientInfo: { + name: "sse-test-client", + version: "1.0", + }, + }, + "init-1", + ) - # The default `mode: :auto` adopts the sessionless modern lifecycle (2026-07-28) - # when the server supports it. This example demonstrates the legacy session's SSE stream, - # so pin the legacy `initialize` handshake. - server_info = client.connect( - client_info: { name: "streamable-http-client", version: "1.0" }, - mode: :legacy, - ) + if init_response[:error] + logger.error("Failed to initialize: #{init_response[:error]}") + exit(1) + end - puts <<~MESSAGE - ID: #{http_transport.session_id} - Version: #{http_transport.protocol_version} - Server: #{server_info["serverInfo"]} + session_id = init_response[:headers]["mcp-session-id"]&.first + + if session_id.nil? + logger.error("No session ID received") + exit(1) + end + + logger.info("Session initialized: #{session_id}") + logger.info("Server info: #{init_response[:body]["result"]["serverInfo"]}") + + # Step 2: Start SSE connection in a separate thread + sse_thread = Thread.new { connect_sse(session_id, logger) } + + # Give SSE time to connect + sleep(1) + + # Step 3: Interactive menu + loop do + puts <<~MESSAGE.chomp + + === Available Actions === + 1. Send custom notification + 2. Test echo + 3. List tools + 0. Exit + + Choose an action:#{" "} MESSAGE - unless http_transport.session_id - logger.error("No session ID received; this example requires a stateful Streamable HTTP session.") - return - end + choice = gets.chomp - puts "=== Listing tools ===" - tools = client.tools - tools.each { |tool| puts " - #{tool.name}: #{tool.description}" } + case choice + when "1" + print("Enter notification message: ") + message = gets.chomp + print("Enter delay in seconds (0 for immediate): ") + delay = gets.chomp.to_f - echo_tool = tools.find { |tool| tool.name == "echo" } - notification_tool = tools.find { |tool| tool.name == "notification_tool" } - - sse_thread = Thread.new { connect_sse(http_transport.session_id, logger) } - sleep(1) - - loop do - puts <<~MENU.chomp - - === Available Actions === - 1. Send notification (triggers SSE event) - 2. Echo message - 3. Show cached tools - 0. Exit - - Choose an action:#{" "} - MENU - - case gets.chomp - when "1" - if notification_tool - print("Enter notification message: ") - message = gets.chomp - print("Enter delay in seconds (0 for immediate): ") - delay = gets.chomp.to_f - - puts "=== Calling tool: notification_tool (raw streaming POST) ===" - raw_request_id += 1 - stream_tool_call( - http_transport.session_id, - "raw-#{raw_request_id}", - name: notification_tool.name, - arguments: { message: message, delay: delay }, - logger: logger, - ) - else - puts "notification_tool not available" - end - when "2" - if echo_tool - print("Enter message to echo: ") - message = gets.chomp - - puts "=== Calling tool: echo ===" - response = client.call_tool(tool: echo_tool, arguments: { message: message }) - print_response(response) - else - puts "echo tool not available" - end - when "3" - puts "=== Cached tools ===" - tools.each { |tool| puts " - #{tool.name}: #{tool.description}" } - when "0" - logger.info("Exiting...") - break + response = make_request( + session_id, + "tools/call", + { + name: "notification_tool", + arguments: { + message: message, + delay: delay, + }, + }, + ) + if response[:body]["accepted"] + logger.info("Notification sent successfully") else - puts "Invalid choice" + logger.error("Error: #{response[:body]["error"]}") end - end - rescue MCP::Client::SessionExpiredError => e - logger.error("Session expired: #{e.message}") - rescue MCP::Client::RequestHandlerError => e - logger.error("Request error: #{e.message}") - rescue Interrupt - logger.info("Client interrupted") - rescue => e - logger.error("Error: #{e.message}") - logger.error(e.backtrace.first(5).join("\n")) - ensure - sse_thread.kill if sse_thread&.alive? - - if http_transport.connected? - puts "=== Closing session ===" - http_transport.close - puts "Session closed" + when "2" + print("Enter message to echo: ") + message = gets.chomp + make_request(session_id, "tools/call", { name: "echo", arguments: { message: message } }) + when "3" + make_request(session_id, "tools/list") + when "0" + logger.info("Exiting...") + break + else + puts "Invalid choice" end end + + # Clean up + sse_thread.kill if sse_thread.alive? + + # Close session + logger.info("Closing session...") + make_request(session_id, "close") + logger.info("Session closed") +rescue Interrupt + logger.info("Client interrupted by user") +rescue => e + logger.error("Client error: #{e.message}") + logger.error(e.backtrace.join("\n")) end -main +# Run the client +if __FILE__ == $PROGRAM_NAME + main +end diff --git a/examples/streamable_http_server.rb b/examples/streamable_http_server.rb index f122296..82566fc 100644 --- a/examples/streamable_http_server.rb +++ b/examples/streamable_http_server.rb @@ -2,7 +2,6 @@ $LOAD_PATH.unshift(File.expand_path("../lib", __dir__)) require "mcp" -require "rack/cors" require "rackup" require "json" require "logger" @@ -13,16 +12,14 @@ sse_logger.formatter = proc do |severity, datetime, _progname, msg| "[SSE] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n" end -# Tool that emits `notifications/progress` events, delivered over the SSE stream. -# The client must request them by sending a `progressToken` in the request `_meta`. +# Tool that returns a response that will be sent via SSE if a stream is active class NotificationTool < MCP::Tool tool_name "notification_tool" - description "Sends the message back as progress notifications via SSE, then returns a summary" + description "Returns a notification message that will be sent via SSE if stream is active" input_schema( properties: { message: { type: "string", description: "Message to send via SSE" }, - steps: { type: "number", description: "Number of progress notifications to send (default: 3)" }, - delay: { type: "number", description: "Delay in seconds between notifications (optional)" }, + delay: { type: "number", description: "Delay in seconds before returning (optional)" }, }, required: ["message"], ) @@ -30,19 +27,14 @@ class NotificationTool < MCP::Tool class << self attr_accessor :logger - def call(message:, server_context:, steps: 3, delay: 0) - steps = steps.to_i.clamp(1, 10) + def call(message:, delay: 0) + sleep(delay) if delay > 0 - steps.times do |i| - sleep(delay) if delay > 0 - - logger&.info("Reporting progress #{i + 1}/#{steps}: #{message}") - server_context.report_progress(i + 1, total: steps, message: message) - end + logger&.info("Returning notification message: #{message}") MCP::Tool::Response.new([{ type: "text", - text: "Sent #{steps} progress notifications for: #{message}", + text: "Notification: #{message} (timestamp: #{Time.now.iso8601})", }]) end end @@ -51,7 +43,6 @@ end # Create the server server = MCP::Server.new( name: "sse_test_server", - version: "1.0.0", tools: [NotificationTool], prompts: [], resources: [], @@ -71,83 +62,75 @@ end # Create the Streamable HTTP transport transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) +server.transport = transport -# Rack middleware for MCP request/response and SSE logging. -class McpSseLogger - def initialize(app) - @app = app - - @mcp_logger = Logger.new($stdout) - @mcp_logger.formatter = proc { |_severity, _datetime, _progname, msg| "[MCP] #{msg}\n" } - - @sse_logger = Logger.new($stdout) - @sse_logger.formatter = proc { |severity, datetime, _progname, msg| "[SSE] #{severity} #{datetime.strftime("%H:%M:%S.%L")} - #{msg}\n" } - end - - def call(env) - if env["REQUEST_METHOD"] == "POST" - body = env["rack.input"].read - env["rack.input"].rewind - - begin - parsed = JSON.parse(body) - - @mcp_logger.info("Request: #{parsed["method"]} (id: #{parsed["id"]})") - @sse_logger.info("New client initializing session") if parsed["method"] == "initialize" - rescue JSON::ParserError - @mcp_logger.warn("Invalid JSON in request") - end - elsif env["REQUEST_METHOD"] == "GET" - session_id = env["HTTP_MCP_SESSION_ID"] || Rack::Utils.parse_query(env["QUERY_STRING"])["sessionId"] - - @sse_logger.info("SSE connection request for session: #{session_id}") - end - - status, headers, response_body = @app.call(env) - - if response_body.is_a?(Array) && !response_body.empty? && env["REQUEST_METHOD"] == "POST" - begin - parsed = JSON.parse(response_body.first) - - if parsed["error"] - @mcp_logger.error("Response error: #{parsed["error"]["message"]}") - else - @mcp_logger.info("Response: success (id: #{parsed["id"]})") - @sse_logger.info("Session created: #{headers["mcp-session-id"]}") if headers["mcp-session-id"] - end - rescue JSON::ParserError - @mcp_logger.warn("Invalid JSON in response") - end - elsif env["REQUEST_METHOD"] == "GET" && status == 200 - @sse_logger.info("SSE stream established") - end - - [status, headers, response_body] - end +# Create a logger for MCP request/response logging +mcp_logger = Logger.new($stdout) +mcp_logger.formatter = proc do |_severity, _datetime, _progname, msg| + "[MCP] #{msg}\n" end -# Build the Rack application with middleware. -# `StreamableHTTPTransport` responds to `call(env)`, so it can be used directly as a Rack app. -rack_app = Rack::Builder.new do - # Enable CORS to allow browser-based MCP clients (e.g., MCP Inspector) - # WARNING: origins("*") allows all origins. Restrict this in production. - use(Rack::Cors) do - allow do - origins("*") - resource( - "*", - headers: :any, - methods: [:get, :post, :delete, :options], - expose: ["Mcp-Session-Id"], - ) +# Create the Rack application +app = proc do |env| + request = Rack::Request.new(env) + + # Log request details + if request.post? + body = request.body.read + request.body.rewind + begin + parsed_body = JSON.parse(body) + mcp_logger.info("Request: #{parsed_body["method"]} (id: #{parsed_body["id"]})") + + # Log SSE-specific setup + if parsed_body["method"] == "initialize" + sse_logger.info("New client initializing session") + end + rescue JSON::ParserError + mcp_logger.warn("Invalid JSON in request") end + elsif request.get? + session_id = request.env["HTTP_MCP_SESSION_ID"] || + Rack::Utils.parse_query(request.env["QUERY_STRING"])["sessionId"] + sse_logger.info("SSE connection request for session: #{session_id}") end + # Handle the request + response = transport.handle_request(request) + + # Log response details + status, headers, body = response + if body.is_a?(Array) && !body.empty? && request.post? + begin + parsed_response = JSON.parse(body.first) + if parsed_response["error"] + mcp_logger.error("Response error: #{parsed_response["error"]["message"]}") + elsif parsed_response["accepted"] + # Response was sent via SSE + sse_logger.info("Response sent via SSE stream") + else + mcp_logger.info("Response: success (id: #{parsed_response["id"]})") + + # Log session ID for initialization + if headers["Mcp-Session-Id"] + sse_logger.info("Session created: #{headers["Mcp-Session-Id"]}") + end + end + rescue JSON::ParserError + mcp_logger.warn("Invalid JSON in response") + end + elsif request.get? && status == 200 + sse_logger.info("SSE stream established") + end + + response +end + +# Build the Rack application with middleware +rack_app = Rack::Builder.new do use(Rack::CommonLogger, Logger.new($stdout)) use(Rack::ShowExceptions) - use(McpSseLogger) - - run(transport) + run(app) end # Print usage instructions @@ -157,34 +140,29 @@ puts <<~MESSAGE Starting server on http://localhost:9393 Available Tools: - 1. notification_tool - Sends the message back as progress notifications via SSE + 1. NotificationTool - Returns messages that are sent via SSE when stream is active" 2. echo - Simple echo tool Testing SSE: 1. Initialize session: curl -i http://localhost:9393 \\ - -H "Accept: application/json, text/event-stream" \\ - --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"sse-test","version":"1.0"}}}' + --json '{"jsonrpc":"2.0","method":"initialize","id":1,"params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"sse-test","version":"1.0"}}}' - 2. Connect SSE stream (use the session ID from step 1): + 2. Connect SSE stream (use the session ID from step 1):" curl -i -N -H "Mcp-Session-Id: YOUR_SESSION_ID" http://localhost:9393 3. In another terminal, test tools (responses will be sent via SSE if stream is active): Echo tool: curl -i http://localhost:9393 -H "Mcp-Session-Id: YOUR_SESSION_ID" \\ - -H "Accept: application/json, text/event-stream" \\ --json '{"jsonrpc":"2.0","method":"tools/call","id":2,"params":{"name":"echo","arguments":{"message":"Hello SSE!"}}}' - Notification tool (progress notifications require a progressToken in _meta): + Notification tool (with 2 second delay): curl -i http://localhost:9393 -H "Mcp-Session-Id: YOUR_SESSION_ID" \\ - -H "Accept: application/json, text/event-stream" \\ - --json '{"jsonrpc":"2.0","method":"tools/call","id":3,"params":{"name":"notification_tool","arguments":{"message":"Hello SSE!","delay":1},"_meta":{"progressToken":"curl-progress"}}}' + --json '{"jsonrpc":"2.0","method":"tools/call","id":3,"params":{"name":"notification_tool","arguments":{"message":"Hello SSE!", "delay": 2}}}' - Note: Each POST is answered with an SSE stream of its own; request-scoped notifications - (such as the progress events above) appear on it before the final response. - The standalone GET stream carries server-initiated messages that are not tied to a request. + Note: When an SSE stream is active, tool responses will appear in the SSE stream and the POST request will return {"accepted": true} Press Ctrl+C to stop the server MESSAGE diff --git a/lib/json_rpc_handler.rb b/lib/json_rpc_handler.rb index 6cbce1c..536406d 100644 --- a/lib/json_rpc_handler.rb +++ b/lib/json_rpc_handler.rb @@ -16,12 +16,7 @@ module JsonRpcHandler PARSE_ERROR = -32700 end - DEFAULT_ALLOWED_ID_CHARACTERS = /\A[a-zA-Z0-9_-]+\z/.freeze - - # Sentinel return value from a handler. When a handler returns this, - # `process_request` emits no JSON-RPC response for the request, - # matching the notification-style semantics (id is ignored). - NO_RESPONSE = Object.new.freeze + DEFAULT_ALLOWED_ID_CHARACTERS = /\A[a-zA-Z0-9_-]+\z/ extend self @@ -63,45 +58,23 @@ module JsonRpcHandler message: "Parse error", data: "Invalid JSON", }) - rescue StandardError - # Last-resort guard so an unexpected handling error returns a JSON-RPC error - # instead of escaping to the transport loop. - response = error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: { - code: ErrorCode::INTERNAL_ERROR, - message: "Internal error", - }) end response&.to_json end def process_request(request, id_validation_pattern:, &method_finder) - # A batch element can be any JSON value; a non-object element cannot carry an id or a method, - # so reject it before the `request[:id]` access below. - unless request.is_a?(Hash) - return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: { - code: ErrorCode::INVALID_REQUEST, - message: "Invalid Request", - data: "Request must be an object", - }) - end - id = request[:id] error = if !valid_version?(request[:jsonrpc]) "JSON-RPC version must be 2.0" - elsif !valid_id?(id, id_validation_pattern) + elsif !valid_id?(request[:id], id_validation_pattern) "Request ID must match validation pattern, or be an integer or null" elsif !valid_method_name?(request[:method]) 'Method name must be a string and not start with "rpc."' end - # Per JSON-RPC 2.0 (Response object, `id`), the error response must carry - # the same id as the request when the id could be detected; null is only - # for requests whose id could not be determined. `error_response` nils out - # ids that fail validation, and the `:unknown_id` sentinel keeps a response - # (with a null id) being emitted when the request carried no id at all. - return error_response(id: id.nil? ? :unknown_id : id, id_validation_pattern: id_validation_pattern, error: { + return error_response(id: :unknown_id, id_validation_pattern: id_validation_pattern, error: { code: ErrorCode::INVALID_REQUEST, message: "Invalid Request", data: error, @@ -119,7 +92,7 @@ module JsonRpcHandler end begin - method = method_finder.call(method_name, id) + method = method_finder.call(method_name) if method.nil? return error_response(id: id, id_validation_pattern: id_validation_pattern, error: { @@ -130,46 +103,17 @@ module JsonRpcHandler end result = method.call(params) - return if result.equal?(NO_RESPONSE) success_response(id: id, result: result) - rescue MCP::Server::RequestHandlerError => e - handle_request_error(e, id, id_validation_pattern) - rescue StandardError - # The exception message is deliberately not echoed into `data`: it can carry - # internals that must not reach untrusted clients (CWE-209). + rescue StandardError => e error_response(id: id, id_validation_pattern: id_validation_pattern, error: { code: ErrorCode::INTERNAL_ERROR, message: "Internal error", + data: e.message, }) end end - def handle_request_error(error, id, id_validation_pattern) - if error.respond_to?(:error_code) && error.error_code - code = error.error_code - message = error.message - else - error_type = error.respond_to?(:error_type) ? error.error_type : nil - - code, message = case error_type - when :invalid_request then [ErrorCode::INVALID_REQUEST, "Invalid Request"] - when :invalid_params then [ErrorCode::INVALID_PARAMS, "Invalid params"] - when :parse_error then [ErrorCode::PARSE_ERROR, "Parse error"] - when :internal_error then [ErrorCode::INTERNAL_ERROR, "Internal error"] - else [ErrorCode::INTERNAL_ERROR, "Internal error"] - end - end - - data = error.respond_to?(:error_data) && error.error_data ? error.error_data : error.message - - error_response(id: id, id_validation_pattern: id_validation_pattern, error: { - code: code, - message: message, - data: data, - }) - end - def valid_version?(version) version == Version::V2_0 end diff --git a/lib/mcp.rb b/lib/mcp.rb index 2213f23..c918f77 100644 --- a/lib/mcp.rb +++ b/lib/mcp.rb @@ -2,31 +2,34 @@ require_relative "json_rpc_handler" require_relative "mcp/configuration" -require_relative "mcp/protocol_deprecations" +require_relative "mcp/content" +require_relative "mcp/icon" +require_relative "mcp/instrumentation" +require_relative "mcp/methods" +require_relative "mcp/prompt" +require_relative "mcp/prompt/argument" +require_relative "mcp/prompt/message" +require_relative "mcp/prompt/result" +require_relative "mcp/resource" +require_relative "mcp/resource/contents" +require_relative "mcp/resource/embedded" +require_relative "mcp/resource_template" +require_relative "mcp/server" +require_relative "mcp/server/transports/streamable_http_transport" +require_relative "mcp/server/transports/stdio_transport" require_relative "mcp/string_utils" +require_relative "mcp/tool" +require_relative "mcp/tool/input_schema" +require_relative "mcp/tool/output_schema" +require_relative "mcp/tool/response" +require_relative "mcp/tool/annotations" require_relative "mcp/transport" require_relative "mcp/version" +require_relative "mcp/client" +require_relative "mcp/client/http" +require_relative "mcp/client/tool" module MCP - autoload :Annotations, "mcp/annotations" - autoload :Apps, "mcp/apps" - autoload :Cancellation, "mcp/cancellation" - autoload :CancelledError, "mcp/cancelled_error" - autoload :Client, "mcp/client" - autoload :Content, "mcp/content" - autoload :Elicitation, "mcp/elicitation" - autoload :ErrorCodes, "mcp/error_codes" - autoload :Icon, "mcp/icon" - autoload :Prompt, "mcp/prompt" - autoload :RequestEnvelope, "mcp/request_envelope" - autoload :Resource, "mcp/resource" - autoload :ResourceTemplate, "mcp/resource_template" - autoload :ResultType, "mcp/result_type" - autoload :Server, "mcp/server" - autoload :ServerSession, "mcp/server_session" - autoload :Tool, "mcp/tool" - autoload :TraceContext, "mcp/trace_context" - class << self def configure yield(configuration) @@ -36,4 +39,13 @@ module MCP @configuration ||= Configuration.new end end + + class Annotations + attr_reader :audience, :priority + + def initialize(audience: nil, priority: nil) + @audience = audience + @priority = priority + end + end end diff --git a/lib/mcp/annotations.rb b/lib/mcp/annotations.rb deleted file mode 100644 index f8562f2..0000000 --- a/lib/mcp/annotations.rb +++ /dev/null @@ -1,28 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Annotations - SUPPORTED_AUDIENCES = ["user", "assistant"].freeze - - attr_reader :audience, :priority, :last_modified - - def initialize(audience: nil, priority: nil, last_modified: nil) - if audience && !(audience.is_a?(Array) && audience.all? { |role| SUPPORTED_AUDIENCES.include?(role) }) - raise ArgumentError, 'The value of audience must be an array of "user" or "assistant".' - end - raise ArgumentError, "The value of priority must be between 0 and 1." if priority && !priority.between?(0, 1) - - @audience = audience - @priority = priority - @last_modified = last_modified - end - - def to_h - { - audience: audience, - priority: priority, - lastModified: last_modified, - }.compact - end - end -end diff --git a/lib/mcp/apps.rb b/lib/mcp/apps.rb deleted file mode 100644 index de09192..0000000 --- a/lib/mcp/apps.rb +++ /dev/null @@ -1,109 +0,0 @@ -# frozen_string_literal: true - -module MCP - # Server-side helpers for the MCP Apps extension (SEP-1865, Extensions Track, Final): - # interactive user interfaces delivered as `ui://` HTML template resources that hosts - # render for tool results. The extension is negotiated per SEP-2133 through - # `capabilities.extensions` on both sides; a server declares {EXTENSION_ID}, registers - # UI templates as ordinary resources, and links tools to templates via `_meta`. - # - # Everything else defined by the extension (the sandboxed iframe, the `ui/*` - # postMessage bridge methods, consent for UI-initiated calls) is HOST responsibility: - # a server only ever receives ordinary `resources/read` and `tools/call` requests. - # - # Because the extension is optional, a UI-enabled tool MUST still return a meaningful - # text-only result for clients that did not declare the capability; - # use {Apps.client_supports?} to branch. - # - # @example Declaring an Apps-enabled server - # capabilities = MCP::Server::Capabilities.new - # capabilities.support_tools - # capabilities.support_resources - # capabilities.support_extensions(MCP::Apps.capability) - # server = MCP::Server.new( - # name: "weather_server", - # capabilities: capabilities, - # resources: [MCP::Apps.ui_resource(uri: "ui://weather-server/dashboard", name: "weather_dashboard")], - # ) - # server.define_tool( - # name: "get_weather", - # meta: MCP::Apps.tool_meta(resource_uri: "ui://weather-server/dashboard"), - # ) { |server_context:| - # ... - # } - # - # https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx - module Apps - # Reverse-DNS extension identifier (note: `/ui`, not `/apps`), shared wire vocabulary with - # the reference `@modelcontextprotocol/ext-apps` package and the Python SDK's `Apps` extension. - EXTENSION_ID = "io.modelcontextprotocol/ui" - # UI template resources MUST use this parameterized MIME type. - RESOURCE_MIME_TYPE = "text/html;profile=mcp-app" - # UI template resource URIs MUST use this scheme. - URI_SCHEME = "ui://" - # Legacy flat `_meta` key linking a tool to its template; the canonical shape is - # the nested `_meta.ui.resourceUri`. {Apps.tool_meta} can emit both. - RESOURCE_URI_META_KEY = "ui/resourceUri" - - extend self - - # The `capabilities.extensions` fragment advertising Apps support. Pass to - # `MCP::Server::Capabilities.new(extensions: ...)` or `support_extensions(...)`, - # or merge into a client's `connect(capabilities: { extensions: ... })`. - def capability(mime_types: [RESOURCE_MIME_TYPE]) - { EXTENSION_ID => { mimeTypes: mime_types } } - end - - # Builds an `MCP::Resource` for a UI template, enforcing the spec's MUSTs: - # a `ui://` URI and the `text/html;profile=mcp-app` MIME type by default. - def ui_resource(uri:, name:, mime_type: RESOURCE_MIME_TYPE, **rest) - unless uri.is_a?(String) && uri.start_with?(URI_SCHEME) - raise ArgumentError, "MCP Apps template URIs must start with #{URI_SCHEME.inspect} (got #{uri.inspect})" - end - - Resource.new(uri: uri, name: name, mime_type: mime_type, **rest) - end - - # Builds the tool `_meta` linking a tool to its UI template, merged non-destructively into - # caller-supplied `meta`. `visibility` restricts who sees the tool (an array of `"model"` / `"app"`). - # `legacy: true` also writes the flat `"ui/resourceUri"` alias, matching the reference server helper - # that keeps both key shapes in sync for older hosts. - def tool_meta(resource_uri:, visibility: nil, meta: nil, legacy: false) - unless resource_uri.is_a?(String) && resource_uri.start_with?(URI_SCHEME) - raise ArgumentError, "resource_uri must start with #{URI_SCHEME.inspect} (got #{resource_uri.inspect})" - end - - ui_entry = { resourceUri: resource_uri } - ui_entry[:visibility] = visibility if visibility - - merged = (meta || {}).merge(ui: ui_entry) - merged[RESOURCE_URI_META_KEY.to_sym] = resource_uri if legacy - merged - end - - # Whether the client declared Apps support for `mime_type` in its `capabilities.extensions` - # (symbol or string keys). UI-enabled tools use this to fall back to a text-only result for - # clients without the extension. - def client_supports?(client_capabilities, mime_type: RESOURCE_MIME_TYPE) - extensions = read_key(client_capabilities, :extensions) - declaration = read_key(extensions, EXTENSION_ID) - return false unless declaration.is_a?(Hash) - - mime_types = read_key(declaration, :mimeTypes) - - # A declaration without mimeTypes advertises the extension without narrowing. - return true if mime_types.nil? - - mime_types.is_a?(Array) && mime_types.include?(mime_type) - end - - private - - def read_key(hash, key) - return unless hash.is_a?(Hash) - - value = hash[key.to_sym] - value.nil? ? hash[key.to_s] : value - end - end -end diff --git a/lib/mcp/cancellation.rb b/lib/mcp/cancellation.rb deleted file mode 100644 index b702ae2..0000000 --- a/lib/mcp/cancellation.rb +++ /dev/null @@ -1,72 +0,0 @@ -# frozen_string_literal: true - -require_relative "cancelled_error" - -module MCP - class Cancellation - attr_reader :reason, :request_id - - def initialize(request_id: nil) - @request_id = request_id - @reason = nil - @cancelled = false - @callbacks = [] - @mutex = Mutex.new - end - - def cancelled? - @mutex.synchronize { @cancelled } - end - - def cancel(reason: nil) - callbacks = @mutex.synchronize do - return false if @cancelled - - @cancelled = true - @reason = reason - @callbacks.tap { @callbacks = [] } - end - - callbacks.each do |callback| - callback.call(reason) - rescue StandardError => e - MCP.configuration.exception_reporter.call(e, { error: "Cancellation callback failed" }) - end - - true - end - - # Registers a callback invoked synchronously on the first `cancel` call. - # If already cancelled, fires immediately. - # - # Returns the block itself as a handle that can be passed to `off_cancel` - # to deregister it (e.g. when a nested request completes normally and the - # hook should not fire on a later parent cancellation). - def on_cancel(&block) - fire_now = false - @mutex.synchronize do - if @cancelled - fire_now = true - else - @callbacks << block - end - end - - block.call(@reason) if fire_now - block - end - - # Removes a previously-registered `on_cancel` callback. Returns `true` - # if the callback was still pending (i.e. had not yet fired), `false` - # otherwise. Safe to call with `nil`. - def off_cancel(handle) - return false unless handle - - @mutex.synchronize { !@callbacks.delete(handle).nil? } - end - - def raise_if_cancelled! - raise CancelledError.new(request_id: @request_id, reason: @reason) if cancelled? - end - end -end diff --git a/lib/mcp/cancelled_error.rb b/lib/mcp/cancelled_error.rb deleted file mode 100644 index 767e6f9..0000000 --- a/lib/mcp/cancelled_error.rb +++ /dev/null @@ -1,13 +0,0 @@ -# frozen_string_literal: true - -module MCP - class CancelledError < StandardError - attr_reader :request_id, :reason - - def initialize(message = "Request was cancelled", request_id: nil, reason: nil) - super(message) - @request_id = request_id - @reason = reason - end - end -end diff --git a/lib/mcp/client.rb b/lib/mcp/client.rb index 7c9d8b9..7ecf39a 100644 --- a/lib/mcp/client.rb +++ b/lib/mcp/client.rb @@ -1,31 +1,134 @@ # frozen_string_literal: true -require_relative "client/elicitation" -require_relative "client/mcp_param_headers" -require_relative "client/modern_envelope" -require_relative "client/oauth" -require_relative "client/stdio" -require_relative "client/http" -require_relative "client/paginated_result" -require_relative "client/tool" -require_relative "result_type" - module MCP class Client - # Upper bound on the number of pages the all-pages methods (`tools`, `resources`, - # `resource_templates`, `prompts`) will walk. The cursor guard in `fetch_all_pages` only - # stops a server that repeats or cycles cursors; one that returns a fresh `nextCursor` on - # every response would otherwise be followed indefinitely, growing the retained pages with it. - MAX_PAGES = 1_000 + # Initializes a new MCP::Client instance. + # + # @param transport [Object] The transport object to use for communication with the server. + # The transport should be a duck type that responds to `send_request`. See the README for more details. + # + # @example + # transport = MCP::Client::HTTP.new(url: "http://localhost:3000") + # client = MCP::Client.new(transport: transport) + def initialize(transport:) + @transport = transport + end - class ServerError < StandardError - attr_reader :code, :data + # The user may want to access additional transport-specific methods/attributes + # So keeping it public + attr_reader :transport - def initialize(message, code:, data: nil) - super(message) - @code = code - @data = data - end + # Returns the list of tools available from the server. + # Each call will make a new request – the result is not cached. + # + # @return [Array] An array of available tools. + # + # @example + # tools = client.tools + # tools.each do |tool| + # puts tool.name + # end + def tools + response = transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "tools/list", + }) + + response.dig("result", "tools")&.map do |tool| + Tool.new( + name: tool["name"], + description: tool["description"], + input_schema: tool["inputSchema"], + ) + end || [] + end + + # Returns the list of resources available from the server. + # Each call will make a new request – the result is not cached. + # + # @return [Array] An array of available resources. + def resources + response = transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "resources/list", + }) + + response.dig("result", "resources") || [] + end + + # Returns the list of prompts available from the server. + # Each call will make a new request – the result is not cached. + # + # @return [Array] An array of available prompts. + def prompts + response = transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "prompts/list", + }) + + response.dig("result", "prompts") || [] + end + + # Calls a tool via the transport layer and returns the full response from the server. + # + # @param tool [MCP::Client::Tool] The tool to be called. + # @param arguments [Object, nil] The arguments to pass to the tool. + # @return [Hash] The full JSON-RPC response from the transport. + # + # @example + # tool = client.tools.first + # response = client.call_tool(tool: tool, arguments: { foo: "bar" }) + # structured_content = response.dig("result", "structuredContent") + # + # @note + # The exact requirements for `arguments` are determined by the transport layer in use. + # Consult the documentation for your transport (e.g., MCP::Client::HTTP) for details. + def call_tool(tool:, arguments: nil) + transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "tools/call", + params: { name: tool.name, arguments: arguments }, + }) + end + + # Reads a resource from the server by URI and returns the contents. + # + # @param uri [String] The URI of the resource to read. + # @return [Array] An array of resource contents (text or blob). + def read_resource(uri:) + response = transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "resources/read", + params: { uri: uri }, + }) + + response.dig("result", "contents") || [] + end + + # Gets a prompt from the server by name and returns its details. + # + # @param name [String] The name of the prompt to get. + # @return [Hash] A hash containing the prompt details. + def get_prompt(name:) + response = transport.send_request(request: { + jsonrpc: JsonRpcHandler::Version::V2_0, + id: request_id, + method: "prompts/get", + params: { name: name }, + }) + + response.fetch("result", {}) + end + + private + + def request_id + SecureRandom.uuid end class RequestHandlerError < StandardError @@ -38,976 +141,5 @@ module MCP @original_error = original_error end end - - # Raised inside a server-to-client request handler (registered via `on_server_request`, e.g. `on_sampling`) - # to answer the request with a specific JSON-RPC error code instead of the default internal error. - # Mirrors the TypeScript SDK's `McpError` and the Python SDK's `ErrorData` return: for example, - # the sampling spec answers a rejected request with code `-1`. - # https://modelcontextprotocol.io/specification/2025-11-25/client/sampling - class ServerRequestError < StandardError - attr_reader :code - - def initialize(message, code:) - super(message) - @code = code - end - end - - # Raised when a server response fails client-side validation, e.g., a success response - # whose `result` field is missing or has the wrong type. This is distinct from a - # server-returned JSON-RPC error, which is raised as `ServerError`. - class ValidationError < StandardError; end - - # Raised when an all-pages method reaches `max_pages` while the server is still offering - # another cursor. Use the single-page `list_*` methods to walk such a collection with - # a policy of your own. - class PaginationLimitError < StandardError; end - - # Raised when a server answers with a SEP-2322 Multi Round-Trip `input_required` result instead of - # a final result. The result is not an error on the wire: it asks the client to fulfill the server's - # `inputRequests` (a map of id => `{ "method" => ..., "params" => ... }` request objects with - # `sampling/createMessage`, `roots/list`, or `elicitation/create` shapes) and re-issue - # the original request with `inputResponses` plus the echoed opaque `requestState`. - # With handlers registered through `on_elicitation`, `on_sampling`, or `on_roots`, the resume loop runs - # automatically; this error surfaces when no matching handler exists (manual driving via - # `input_requests` and the `input_responses:`/`request_state:` kwargs), or when the round cap is exhausted. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2322 - class InputRequiredError < StandardError - attr_reader :input_requests, :request_state, :result - - def initialize(message, input_requests:, request_state: nil, result: nil) - super(message) - @input_requests = input_requests - @request_state = request_state - @result = result - end - end - - # Raised when the server responds 404 to a request containing a session ID, - # indicating the session has expired. Inherits from `RequestHandlerError` for - # backward compatibility with callers that rescue the generic error. Per spec, - # clients MUST start a new session with a fresh `initialize` request in response. - class SessionExpiredError < RequestHandlerError - def initialize(message, request, original_error: nil) - super(message, request, error_type: :not_found, original_error: original_error) - end - end - - # The server's `DiscoverResult` (MCP 2026-07-28, SEP-2575): the modern protocol versions it serves, - # its capabilities and identity, optional instructions, and the REQUIRED `ttlMs`/`cacheScope` cache hints. - DiscoverResult = Struct.new( - :supported_versions, - :capabilities, - :server_info, - :instructions, - :ttl_ms, - :cache_scope, - keyword_init: true, - ) - - # Rounds the SEP-2322 driver runs before giving up, matching the TypeScript and - # Python SDK defaults. Every leg counts, including `requestState`-only retries. - DEFAULT_INPUT_REQUIRED_MAX_ROUNDS = 10 - - # Backoff for `requestState`-only (load shedding) legs: exponential from 50ms to - # a 250ms cap, matching the Python SDK (the TypeScript SDK uses a fixed 250ms). - STATE_ONLY_BACKOFF_INITIAL_SECONDS = 0.05 - STATE_ONLY_BACKOFF_CAP_SECONDS = 0.25 - - # Initializes a new MCP::Client instance. - # - # @param transport [Object] The transport object to use for communication with the server. - # The transport should be a duck type that responds to `send_request`. See the README for more details. - # @param input_required_max_rounds [Integer] Cap on SEP-2322 driver rounds. - # @param max_pages [Integer] Maximum number of pages the all-pages methods ({#tools}, {#resources}, - # {#resource_templates}, {#prompts}) will walk before raising {MCP::Client::PaginationLimitError}. - # - # Once a handler is registered through `on_elicitation`, `on_sampling`, or `on_roots`, `call_tool`, - # `get_prompt`, and `read_resource` resume `input_required` results automatically; without handlers - # (or when a requested kind has no handler) they raise `InputRequiredError` for manual driving, - # exactly as before. - # - # @example - # transport = MCP::Client::HTTP.new(url: "http://localhost:3000") - # client = MCP::Client.new(transport: transport) - def initialize(transport:, input_required_max_rounds: DEFAULT_INPUT_REQUIRED_MAX_ROUNDS, max_pages: MAX_PAGES) - # `nil` or a non-positive value would make the pagination unbounded and silently - # disable the protection, so reject it up front. - unless max_pages.is_a?(Integer) && max_pages > 0 - raise ArgumentError, "max_pages must be a positive Integer" - end - - @transport = transport - @max_pages = max_pages - # Populated by `on_elicitation`, `on_sampling`, and `on_roots`. The same handler answers both ways - # the server can ask for input: a real server-to-client request, and an embedded request inside - # a SEP-2322 `input_required` result. - @input_required_handlers = {} - @input_required_max_rounds = input_required_max_rounds - end - - # The user may want to access additional transport-specific methods/attributes - # So keeping it public - attr_reader :transport - - # The raw handshake result exactly as the server returned it, so its shape depends on the connection's era (SEP-2575): - # after the legacy handshake it is an `InitializeResult` (`protocolVersion`, top-level `serverInfo`), after modern adoption - # it is a `DiscoverResult` (`supportedVersions`, `ttlMs`/`cacheScope`, `serverInfo` optionally under `_meta`). - # Code that must work against both eras should prefer the era-independent readers {#protocol_version}, {#server_capabilities}, - # {#instructions}, and {#server_implementation}; this raw form remains the window to everything they do not cover - # (`supportedVersions`, cache hints, `_meta`, extension data). Returns `nil` before `connect`, after `close`, - # or when the transport does not expose a cached handshake result. - def server_info - transport.server_info if transport.respond_to?(:server_info) - end - - # The protocol version in use on this connection, independent of its era: - # the version negotiated by `initialize` (legacy) or adopted via `server/discover` (modern). - # Returns `nil` before `connect`. - def protocol_version - return transport.protocol_version if transport.respond_to?(:protocol_version) - - server_info&.dig("protocolVersion") - end - - # The server's capabilities Hash, present in both eras. Returns `nil` before `connect`. - def server_capabilities - server_info&.dig("capabilities") - end - - # The server's instructions text, present in both eras when provided. - def instructions - server_info&.dig("instructions") - end - - # The server's identity (`name`/`version`), independent of where the era puts it: top-level `serverInfo` - # on legacy results, the optional `_meta` `io.modelcontextprotocol/serverInfo` stamp on modern results. - # Returns `nil` when a modern server does not identify itself. - def server_implementation - server_info&.dig("_meta", RequestEnvelope::SERVER_INFO_META_KEY) || server_info&.dig("serverInfo") - end - - # Performs the MCP `initialize` handshake by delegating to the transport - # (e.g. `MCP::Client::HTTP`, `MCP::Client::Stdio`). Returns the server's - # `InitializeResult`. - # - # When the transport does not respond to `:connect`, this is a no-op and - # returns `nil`. - # - # @param client_info [Hash, nil] `{ name:, version: }` identifying the client. - # @param protocol_version [String, nil] Protocol version to offer. - # @param capabilities [Hash] Capabilities advertised by the client. May include - # an `extensions` member per SEP-2133, keyed by reverse-DNS extension identifiers, - # e.g. `{ extensions: { "com.example/feature" => {} } }`. - # @param mode [Symbol, nil] Lifecycle selection (SEP-2575). When omitted, transports whose - # `connect` declares `mode:` (the bundled `MCP::Client::HTTP` and `MCP::Client::Stdio`) - # negotiate with `:auto`: probe `server/discover` first and fall back to the legacy handshake - # when the server does not serve a mutually supported modern version. Transports without `mode:` - # keep receiving the historical legacy call shape. `:legacy` forces the `initialize` handshake - # exactly as before; `:modern` requires the modern lifecycle and fails without a mutual modern version. - # Passing an explicit `protocol_version` from a legacy generation (e.g. `"2025-11-25"`) pins - # the legacy handshake without a probe, so an explicitly requested version is never overridden - # by the default negotiation. - # @return [Hash, nil] The server's `InitializeResult` (legacy) or `DiscoverResult` (modern), - # or `nil` when the transport does not expose an explicit handshake. - # Prefer the era-independent readers over inspecting this Hash directly. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#initialization - def connect(client_info: nil, protocol_version: nil, capabilities: {}, mode: nil) - return unless transport.respond_to?(:connect) - - effective_mode = resolve_connect_mode(mode, protocol_version) - - if effective_mode == :legacy - transport.connect( - client_info: client_info, - protocol_version: protocol_version, - capabilities: capabilities, - ) - else - transport.connect( - client_info: client_info, - protocol_version: protocol_version, - capabilities: capabilities, - mode: effective_mode, - ) - end - end - - # Sends `server/discover` (MCP 2026-07-28, SEP-2575): sessionless capability discovery - # that works before (or instead of) `connect`. - # - # @param meta [Hash, nil] Additional `_meta` entries to send with the request. - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [MCP::Client::DiscoverResult] - # @raise [ServerError] If the server returns a JSON-RPC error. - # @raise [ValidationError] If the response `result` is missing or not a Hash. - def discover(meta: nil, cancellation: nil) - response = request(method: Methods::SERVER_DISCOVER, meta: meta, cancellation: cancellation) - result = response.is_a?(Hash) ? response["result"] : nil - raise ValidationError, "Response validation failed: missing or invalid `result`" unless result.is_a?(Hash) - - DiscoverResult.new( - supported_versions: result["supportedVersions"], - capabilities: result["capabilities"], - # The finalized spec (PR #3002) stamps the server identity into the result `_meta`; - # the top-level fallback tolerates servers built against the frozen SEP text. - server_info: result.dig("_meta", RequestEnvelope::SERVER_INFO_META_KEY) || result["serverInfo"], - instructions: result["instructions"], - ttl_ms: result["ttlMs"], - cache_scope: result["cacheScope"], - ) - end - - # Returns true once `connect` has completed the handshake on the underlying - # transport. Transports that do not expose connection state are assumed - # connected and return `true`. - def connected? - return transport.connected? if transport.respond_to?(:connected?) - - true - end - - # Returns a single page of tools from the server. - # - # @param cursor [String, nil] Cursor from a previous page response. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional token; cancelling it sends - # `notifications/cancelled` to the server and raises `MCP::CancelledError` from this call. - # @return [MCP::Client::ListToolsResult] Result with `tools` (Array) - # and `next_cursor` (String or nil). - # - # @example Iterate all pages - # cursor = nil - # loop do - # page = client.list_tools(cursor: cursor) - # page.tools.each { |tool| puts tool.name } - # cursor = page.next_cursor - # break unless cursor - # end - def list_tools(cursor: nil, meta: nil, cancellation: nil) - params = cursor ? { cursor: cursor } : nil - response = request(method: "tools/list", params: params, meta: meta, cancellation: cancellation) - result = response["result"] || {} - - tools = (result["tools"] || []).filter_map do |tool| - next if exclude_invalid_x_mcp_header?(tool) - - Tool.new( - name: tool["name"], - description: tool["description"], - input_schema: tool["inputSchema"], - output_schema: tool["outputSchema"], - annotations: tool["annotations"], - ) - end - - ListToolsResult.new( - tools: tools, - next_cursor: result["nextCursor"], - meta: result["_meta"], - ttl_ms: result["ttlMs"], - cache_scope: result["cacheScope"], - ) - end - - # Returns every tool available on the server. Iterates through all pages automatically - # when the server paginates, so the full collection is returned regardless of the server's `page_size` setting. - # Use {#list_tools} when you need fine-grained cursor control. - # - # Each call will make a new request - the result is not cached. - # - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # Cancelling it aborts whichever page is currently in flight; pages already returned are kept, - # but the call raises `MCP::CancelledError` instead of returning the partial set. - # @return [Array] An array of available tools. - # @raise [MCP::Client::PaginationLimitError] If the server offers more than `max_pages` pages. - # - # @example - # tools = client.tools - # tools.each do |tool| - # puts tool.name - # end - def tools(cancellation: nil) - # TODO: consider renaming to `list_all_tools`. - fetch_all_pages { |cursor| list_tools(cursor: cursor, cancellation: cancellation) }.flat_map(&:tools) - end - - # Returns a single page of resources from the server. - # - # @param cursor [String, nil] Cursor from a previous page response. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [MCP::Client::ListResourcesResult] Result with `resources` (Array) - # and `next_cursor` (String or nil). - def list_resources(cursor: nil, meta: nil, cancellation: nil) - params = cursor ? { cursor: cursor } : nil - response = request(method: "resources/list", params: params, meta: meta, cancellation: cancellation) - result = response["result"] || {} - - ListResourcesResult.new( - resources: result["resources"] || [], - next_cursor: result["nextCursor"], - meta: result["_meta"], - ttl_ms: result["ttlMs"], - cache_scope: result["cacheScope"], - ) - end - - # Returns every resource available on the server. Iterates through all pages automatically - # when the server paginates, so the full collection is returned regardless of the server's `page_size` setting. - # Use {#list_resources} when you need fine-grained cursor control. - # - # Each call will make a new request - the result is not cached. - # - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token (see {#tools}). - # @return [Array] An array of available resources. - # @raise [MCP::Client::PaginationLimitError] See {#tools}. - def resources(cancellation: nil) - # TODO: consider renaming to `list_all_resources`. - fetch_all_pages { |cursor| list_resources(cursor: cursor, cancellation: cancellation) }.flat_map(&:resources) - end - - # Returns a single page of resource templates from the server. - # - # @param cursor [String, nil] Cursor from a previous page response. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [MCP::Client::ListResourceTemplatesResult] Result with `resource_templates` - # (Array) and `next_cursor` (String or nil). - def list_resource_templates(cursor: nil, meta: nil, cancellation: nil) - params = cursor ? { cursor: cursor } : nil - response = request(method: "resources/templates/list", params: params, meta: meta, cancellation: cancellation) - result = response["result"] || {} - - ListResourceTemplatesResult.new( - resource_templates: result["resourceTemplates"] || [], - next_cursor: result["nextCursor"], - meta: result["_meta"], - ttl_ms: result["ttlMs"], - cache_scope: result["cacheScope"], - ) - end - - # Returns every resource template available on the server. Iterates through all pages automatically - # when the server paginates, so the full collection is returned regardless of the server's `page_size` setting. - # Use {#list_resource_templates} when you need fine-grained cursor control. - # - # Each call will make a new request - the result is not cached. - # - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token (see {#tools}). - # @return [Array] An array of available resource templates. - # @raise [MCP::Client::PaginationLimitError] See {#tools}. - def resource_templates(cancellation: nil) - # TODO: consider renaming to `list_all_resource_templates`. - fetch_all_pages { |cursor| list_resource_templates(cursor: cursor, cancellation: cancellation) }.flat_map(&:resource_templates) - end - - # Returns a single page of prompts from the server. - # - # @param cursor [String, nil] Cursor from a previous page response. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [MCP::Client::ListPromptsResult] Result with `prompts` (Array) - # and `next_cursor` (String or nil). - def list_prompts(cursor: nil, meta: nil, cancellation: nil) - params = cursor ? { cursor: cursor } : nil - response = request(method: "prompts/list", params: params, meta: meta, cancellation: cancellation) - result = response["result"] || {} - - ListPromptsResult.new( - prompts: result["prompts"] || [], - next_cursor: result["nextCursor"], - meta: result["_meta"], - ttl_ms: result["ttlMs"], - cache_scope: result["cacheScope"], - ) - end - - # Returns every prompt available on the server. Iterates through all pages automatically - # when the server paginates, so the full collection is returned regardless of the server's `page_size` setting. - # Use {#list_prompts} when you need fine-grained cursor control. - # - # Each call will make a new request - the result is not cached. - # - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token (see {#tools}). - # @return [Array] An array of available prompts. - # @raise [MCP::Client::PaginationLimitError] See {#tools}. - def prompts(cancellation: nil) - # TODO: consider renaming to `list_all_prompts`. - fetch_all_pages { |cursor| list_prompts(cursor: cursor, cancellation: cancellation) }.flat_map(&:prompts) - end - - # Calls a tool via the transport layer and returns the full response from the server. - # - # @param name [String] The name of the tool to call. - # @param tool [MCP::Client::Tool] The tool to be called. - # @param arguments [Object, nil] The arguments to pass to the tool. - # @param progress_token [String, Integer, nil] A token to request progress notifications from the server during tool execution. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. the W3C Trace Context keys reserved by SEP-414 - # (`MCP::TraceContext::TRACEPARENT_META_KEY`, `tracestate`, `baggage`). - # `progress_token` takes precedence over a `progressToken` entry in `meta`. - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. Cancelling it from another thread - # sends `notifications/cancelled` to the server and raises `MCP::CancelledError` from this call. - # @return [Hash] The full JSON-RPC response from the transport. - # - # @example Call by name - # response = client.call_tool(name: "my_tool", arguments: { foo: "bar" }) - # content = response.dig("result", "content") - # - # @example Call with a tool object - # tool = client.tools.first - # response = client.call_tool(tool: tool, arguments: { foo: "bar" }) - # structured_content = response.dig("result", "structuredContent") - # - # @example Cancellable call - # cancellation = MCP::Cancellation.new - # Thread.new do - # client.call_tool(name: "slow_tool", arguments: {}, cancellation: cancellation) - # rescue MCP::CancelledError - # # cleanup - # end - # cancellation.cancel(reason: "user pressed cancel") - # - # @note - # The exact requirements for `arguments` are determined by the transport layer in use. - # Consult the documentation for your transport (e.g., MCP::Client::HTTP) for details. - # @param input_responses [Hash, nil] SEP-2322 answers to a previous `input_required` result's `inputRequests`, - # keyed identically (manual retry legs). - # @param request_state [String, nil] The opaque `requestState` echoed back byte-exactly. - def call_tool(name: nil, tool: nil, arguments: nil, progress_token: nil, meta: nil, cancellation: nil, input_responses: nil, request_state: nil) - tool_name = name || tool&.name - raise ArgumentError, "Either `name:` or `tool:` must be provided." unless tool_name - - params = { name: tool_name, arguments: arguments } - meta_entries = meta ? meta.dup : {} - if progress_token - meta_entries.delete("progressToken") - meta_entries[:progressToken] = progress_token - end - params[:_meta] = meta_entries unless meta_entries.empty? - params[:inputResponses] = input_responses if input_responses - params[:requestState] = request_state if request_state - - drive_input_required(method: "tools/call", params: params, cancellation: cancellation) - end - - # Reads a resource from the server by URI and returns the contents. - # - # @param uri [String] The URI of the resource to read. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [Array] An array of resource contents (text or blob). - def read_resource(uri:, meta: nil, cancellation: nil, input_responses: nil, request_state: nil) - params = { uri: uri } - params = params.merge(_meta: meta) if meta && !meta.empty? - params[:inputResponses] = input_responses if input_responses - params[:requestState] = request_state if request_state - - response = drive_input_required(method: "resources/read", params: params, cancellation: cancellation) - - response.dig("result", "contents") || [] - end - - # Gets a prompt from the server by name and returns its details. - # - # @param name [String] The name of the prompt to get. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [Hash] A hash containing the prompt details. - def get_prompt(name:, meta: nil, cancellation: nil, input_responses: nil, request_state: nil) - params = { name: name } - params = params.merge(_meta: meta) if meta && !meta.empty? - params[:inputResponses] = input_responses if input_responses - params[:requestState] = request_state if request_state - - response = drive_input_required(method: "prompts/get", params: params, cancellation: cancellation) - - response.fetch("result", {}) - end - - # Requests completion suggestions from the server for a prompt argument or resource template URI. - # - # @param ref [Hash] The reference, e.g. `{ type: "ref/prompt", name: "my_prompt" }` - # or `{ type: "ref/resource", uri: "file:///{path}" }`. - # @param argument [Hash] The argument being completed, e.g. `{ name: "language", value: "py" }`. - # @param context [Hash, nil] Optional context with previously resolved arguments. - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [Hash] The completion result with `"values"`, `"hasMore"`, and optionally `"total"`. - def complete(ref:, argument:, context: nil, meta: nil, cancellation: nil) - params = { ref: ref, argument: argument } - params[:context] = context if context - - response = request(method: "completion/complete", params: params, meta: meta, cancellation: cancellation) - - response.dig("result", "completion") || { "values" => [], "hasMore" => false } - end - - # Registers a handler for `elicitation/create` requests the server sends while one of - # this client's requests is in flight. The handler receives the request `params` - # (message and `requestedSchema`, string keys) and must return an `ElicitResult`-shaped Hash: - # `{ action: "accept" | "decline" | "cancel", content: { ... } }`. - # - # The same handler answers both ways a server can ask: a real request mid-call, which needs a transport that - # carries server-to-client requests (e.g. `MCP::Client::HTTP`); and an `elicitation/create` embedded in a SEP-2322 - # `input_required` result, which needs no server-to-client route, and is how the modern lifecycle asks now that it - # forbids server-to-client requests. Both routes need `capabilities: { elicitation: {} }` passed to `connect`: per SEP-2322, - # a server MUST NOT embed input requests of a kind the client has not declared. - # - # @example Accept with schema defaults applied (SEP-1034) - # client.on_elicitation do |params| - # { - # action: "accept", - # content: MCP::Client::Elicitation.apply_defaults(params["requestedSchema"]), - # } - # end - # https://modelcontextprotocol.io/specification/2025-11-25/client/elicitation - def on_elicitation(&handler) - register_input_handler(Methods::ELICITATION_CREATE, &handler) - end - - # Registers a handler for `sampling/createMessage` requests the server sends while one of this client's requests is in flight. - # The handler receives the request `params` (`messages`, `maxTokens`, optionally `systemPrompt`, `modelPreferences`, `tools`, - # `toolChoice`, ...; string keys) and must return a `CreateMessageResult`-shaped Hash: - # `{ role: "assistant", content: { type: "text", text: "..." }, model: "...", stopReason: "..." }`. - # - # For trust and safety, the spec recommends a human in the loop able to review, edit, or reject the request and the generated response - # before it is returned to the server. To reject, raise `ServerRequestError` with the spec's user-rejection code `-1`. - # - # The same handler answers both ways a server can ask: a real request mid-call, which needs a transport that - # carries server-to-client requests (e.g. `MCP::Client::HTTP`); and a `sampling/createMessage` embedded in a SEP-2322 - # `input_required` result, which needs no server-to-client route. Both routes need `capabilities: { sampling: {} }` passed to - # `connect` (or `{ sampling: { tools: {} } }` for tool-enabled requests): per SEP-2322, a server MUST NOT embed input requests of - # a kind the client has not declared. - # - # @example Forward the request to an LLM and return its completion - # - # client.on_sampling do |params| - # raise MCP::Client::ServerRequestError.new("User rejected sampling request", code: -1) unless approved?(params) - # - # completion = my_llm.complete(params["messages"], max_tokens: params["maxTokens"]) - # { - # role: "assistant", - # content: { type: "text", text: completion.text }, - # model: completion.model, - # stopReason: "endTurn", - # } - # end - # - # https://modelcontextprotocol.io/specification/2025-11-25/client/sampling - # - # @deprecated MCP Sampling (`sampling/createMessage`) is deprecated as of MCP protocol version 2026-07-28 (SEP-2577). - # Register this handler only to interoperate with servers that still send sampling requests during the deprecation window; - # new servers should call LLM provider APIs directly. - def on_sampling(&handler) - register_input_handler(Methods::SAMPLING_CREATE_MESSAGE, &handler) - end - - # Registers a handler for `roots/list`, answering both a server-to-client request on transports that - # support one and an embedded `roots/list` inside a SEP-2322 `input_required` result. The handler - # receives the request `params` (`nil` for `roots/list`) and must return a `ListRootsResult`-shaped Hash: - # `{ roots: [{ uri: "file:///project", name: "Project" }] }`. - # - # @example - # client.on_roots { { roots: [{ uri: "file:///project", name: "Project" }] } } - # - # @deprecated MCP Roots (`roots/list`) is deprecated as of MCP protocol version 2026-07-28 (SEP-2577). - # Register this handler only to interoperate with servers that still ask for roots. - # - # https://modelcontextprotocol.io/specification/2025-11-25/client/roots - def on_roots(&handler) - register_input_handler(Methods::ROOTS_LIST, &handler) - end - - # Sends a `ping` request to the server to verify the connection is alive. - # Per the MCP spec, the server responds with an empty result. - # - # @param meta [Hash, nil] Additional `_meta` entries to send with the request, - # e.g. SEP-414 trace context (see {MCP::TraceContext}). - # @param cancellation [MCP::Cancellation, nil] Optional cancellation token. - # @return [Hash] An empty hash on success. - # @raise [ServerError] If the server returns a JSON-RPC error. - # @raise [ValidationError] If the response `result` is missing or not a Hash. - # - # @example - # client.ping # => {} - # - # @see https://modelcontextprotocol.io/specification/latest/basic/utilities/ping - def ping(meta: nil, cancellation: nil) - result = request(method: Methods::PING, meta: meta, cancellation: cancellation)["result"] - raise ValidationError, "Response validation failed: missing or invalid `result`" unless result.is_a?(Hash) - - result - end - - private - - # Records a handler for one of the three kinds of input a server can ask this client for, and wires it to - # the transport when the transport can carry server-to-client requests. One registration serves both routes: - # the real request a 2025-11-25 server sends mid-call, and the request embedded in a SEP-2322 - # `input_required` result, which is how the modern lifecycle asks now that it forbids server-to-client - # requests outright. Registering is therefore valid on a transport with no `on_server_request` (stdio, - # and every modern-lifecycle connection); only the wire route is skipped there. - def register_input_handler(method, &handler) - @input_required_handlers[method] = handler - transport.on_server_request(method, &handler) if transport.respond_to?(:on_server_request) - - handler - end - - # SEP-2243: on the modern lifecycle, a tool definition whose `x-mcp-header` annotations violate - # the spec constraints MUST be excluded from `tools/list` results, so one malformed definition - # does not block the valid tools. The TypeScript and Python SDKs filter their listings the same way. - # Legacy connections, and transports without a lifecycle notion, list everything as before. - def exclude_invalid_x_mcp_header?(tool) - return false unless transport.respond_to?(:modern?) && transport.modern? - - scan = McpParamHeaders.scan(tool["inputSchema"]) - return false if scan[:valid] - - warn("MCP::Client: excluding tool #{tool["name"].inspect} from tools/list: #{scan[:reason]}") - true - end - - # Resolves the effective SEP-2575 lifecycle mode for `connect`: - # - # - An explicit `protocol_version` from a legacy generation pins the legacy handshake without a probe, - # so the default negotiation can never override a version the caller asked for. - # - Absent an explicit mode, transports declaring `mode:` negotiate with `:auto`; other transports keep - # the historical legacy call shape. - # - An explicit `:modern`/`:auto` on a transport without `mode:` raises, rather than silently downgrading to - # a lifecycle the caller did not ask for. - def resolve_connect_mode(mode, protocol_version) - unless [nil, :legacy, :modern, :auto].include?(mode) - raise ArgumentError, "mode must be :legacy, :modern, or :auto" - end - - return :legacy if mode == :legacy - return :legacy if mode.nil? && protocol_version && !Configuration.modern_protocol_version?(protocol_version) - - if transport_connect_accepts_mode? - mode || :auto - elsif mode.nil? - :legacy - else - raise ArgumentError, "transport does not support mode: #{mode.inspect}" - end - end - - # `mode:` is forwarded only when the transport's `connect` declares it as a keyword. - # A bare `**kwargs` deliberately does not count, so wrappers and test doubles that - # absorb arbitrary keywords keep the historical legacy call shape. Objects that - # dispatch `connect` through `method_missing` (e.g. mocks) may not support `method`, - # which reads as not declaring `mode:`. - def transport_connect_accepts_mode? - connect_method = begin - transport.method(:connect) - rescue NameError - return false - end - - connect_method.parameters.any? { |type, name| [:key, :keyreq].include?(type) && name == :mode } - end - - # Walks every page of a list endpoint, following `next_cursor`, and returns - # the page results. The `seen` set guards against a server that repeats or - # cycles cursors, and `@max_pages` bounds one that returns a fresh cursor every - # time, so the loop always terminates. - def fetch_all_pages - pages = [] - seen = Set.new - cursor = nil - - loop do - page = yield(cursor) - pages << page - next_cursor = page.next_cursor - break if next_cursor.nil? || seen.include?(next_cursor) - - if pages.size >= @max_pages - raise PaginationLimitError, "Server returned more than #{@max_pages} pages; pass a larger `max_pages:` to " \ - "`MCP::Client.new` if this is expected." - end - - seen << next_cursor - cursor = next_cursor - end - - pages - end - - # Merges caller-supplied `meta` entries into the request params as `_meta`, - # without mutating the caller's hashes. Per SEP-414, `_meta` carries - # request-specific metadata such as W3C trace context (`traceparent`, - # `tracestate`, `baggage`); see {MCP::TraceContext}. - def request(method:, params: nil, meta: nil, cancellation: nil, raise_on_input_required: true) - params = (params || {}).merge(_meta: meta) if meta && !meta.empty? - - request_body = { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: generate_request_id, - method: method, - } - request_body[:params] = params if params - - response = if cancellation - dispatch_with_cancellation(request_body, cancellation) - else - transport.send_request(request: request_body) - end - - # Guard with `is_a?(Hash)` because custom transports may return non-Hash values. - if response.is_a?(Hash) && response.key?("error") - error = response["error"] - raise ServerError.new(error["message"], code: error["code"], data: error["data"]) - end - - raise_on_input_required(response) if raise_on_input_required - - response - end - - # Drives the SEP-2322 multi round-trip loop for `tools/call`, `prompts/get`, and `resources/read`. - # With no configured handlers this degrades to the plain request (an `input_required` result raises - # `InputRequiredError` for manual driving). Otherwise each `inputRequests` entry is fulfilled by - # the matching handler and the ORIGINAL request is re-issued with `inputResponses` under - # the same keys plus the byte-exact echoed `requestState`, on a fresh JSON-RPC id per leg. - # A `requestState`-only result (load shedding) retries after an exponential backoff. - # Every leg counts against `input_required_max_rounds`. - def drive_input_required(method:, params:, cancellation:) - response = request( - method: method, - params: params, - cancellation: cancellation, - raise_on_input_required: @input_required_handlers.empty?, - ) - return response unless input_required?(response) - - original_params = params.dup - original_params.delete(:inputResponses) - original_params.delete(:requestState) - rounds = 0 - backoff = STATE_ONLY_BACKOFF_INITIAL_SECONDS - - loop do - result = response["result"] - rounds += 1 - if rounds > @input_required_max_rounds - raise InputRequiredError.new( - "Server still returned `input_required` after #{@input_required_max_rounds} rounds (SEP-2322).", - input_requests: result["inputRequests"] || {}, - request_state: result["requestState"], - result: result, - ) - end - - input_requests = result["inputRequests"] || {} - responses = nil - if input_requests.empty? - sleep(backoff) - backoff = [backoff * 2, STATE_ONLY_BACKOFF_CAP_SECONDS].min - else - backoff = STATE_ONLY_BACKOFF_INITIAL_SECONDS - responses = fulfill_input_requests(input_requests, result) - end - - retry_params = original_params.dup - retry_params[:inputResponses] = responses if responses - retry_params[:requestState] = result["requestState"] if result["requestState"] - - response = request( - method: method, - params: retry_params, - cancellation: cancellation, - raise_on_input_required: false, - ) - return response unless input_required?(response) - end - end - - # Dispatches every embedded request to its configured handler and collects - # the answers under the same keys. A kind without a handler falls back to - # the manual path by raising `InputRequiredError` with the full result. - def fulfill_input_requests(input_requests, result) - input_requests.each_with_object({}) do |(key, entry), responses| - entry_method = entry.is_a?(Hash) ? entry["method"] || entry[:method] : nil - handler = @input_required_handlers[entry_method] - unless handler - raise InputRequiredError.new( - "Server requested #{entry_method.inspect} input (key #{key.inspect}) but no matching handler " \ - "is configured; inspect `input_requests` to respond manually (SEP-2322).", - input_requests: input_requests, - request_state: result["requestState"], - result: result, - ) - end - - responses[key] = handler.call(entry.is_a?(Hash) ? entry["params"] || entry[:params] : nil) - end - end - - def input_required?(response) - result = response.is_a?(Hash) ? response["result"] : nil - result.is_a?(Hash) && result["resultType"] == ResultType::INPUT_REQUIRED - end - - # Recognizes a SEP-2322 `input_required` result and raises rather than returning it as if it were a final result. - # Servers on stable protocol versions never emit `resultType`, so this is a no-op for them. - def raise_on_input_required(response) - return unless input_required?(response) - - result = response["result"] - raise InputRequiredError.new( - "Server returned `input_required` (SEP-2322). Register a handler with `on_elicitation`, " \ - "`on_sampling`, or `on_roots` to resume automatically, or inspect `input_requests` to respond manually.", - input_requests: result["inputRequests"] || {}, - request_state: result["requestState"], - result: result, - ) - end - - # Generates a fresh JSON-RPC request id for an outgoing request. - # Ids are an internal concern: the public API never accepts or exposes them, and cancellation is driven through - # an `MCP::Cancellation` token instead. - def generate_request_id - SecureRandom.uuid - end - - # Sends `request_body` while watching `cancellation`. The actual blocking `transport.send_request` runs on - # a worker thread; the calling thread waits on a Queue that is woken either by the response or by a cancel signal - # (whichever arrives first - matching the server-side `StreamableHTTPTransport#cancel_pending_request` race contract). - # - # When a cancel wins the race, the calling thread raises `MCP::CancelledError` immediately and the `notifications/cancelled` - # dispatch runs fire-and-forget on its own thread. We deliberately do not wait for that dispatch here: the calling thread - # must not be blocked by a slow or stalled transport write on the cancel path. - # The worker thread is also not force-killed; it stays blocked on the underlying I/O until the server actually responds - # (or the transport closes). This is the same trade-off the server-side `StreamableHTTPTransport#send_request` accepts and - # is noted in the README's Cancellation section. - def dispatch_with_cancellation(request_body, cancellation) - unless transport.respond_to?(:send_notification) - raise NoMethodError, "Cancellation support requires a transport that responds to `send_notification(notification:)` " \ - "so `notifications/cancelled` can be delivered to the peer. The bundled `MCP::Client::Stdio` and `MCP::Client::HTTP` transports " \ - "implement this interface; custom transports must add it before passing `cancellation:` to a request method." - end - - cancellation.raise_if_cancelled! - - request_id = request_body[:id] - queue = Queue.new - - # First-writer-wins gate. Whichever side (worker or on_cancel) flips `completed` first owns the queue's single slot; the loser bails. - # This closes the late-cancel window between the worker pushing `:response` and the main thread completing `dispatch_with_cancellation`, - # where a callback firing in that gap would otherwise emit a stray `notifications/cancelled` for a request that already succeeded. - completion_mutex = Mutex.new - completed = false - sent_mutex = Mutex.new - sent_cond = ConditionVariable.new - request_sent = false - signal_sent = lambda do - sent_mutex.synchronize do - unless request_sent - request_sent = true - sent_cond.broadcast - end - end - end - - Thread.new do - Thread.current.report_on_exception = false - begin - result = transport.send_request(request: request_body, &signal_sent) - completion_mutex.synchronize do - next if completed - - completed = true - queue.push([:response, result]) - end - rescue StandardError => e - completion_mutex.synchronize do - next if completed - - completed = true - queue.push([:error, e]) - end - ensure - # Unblock any waiting cancel-dispatch thread on completion (or error) - # so it does not stall when the transport ignored the block. - signal_sent.call - end - end - - cancel_hook = cancellation.on_cancel do |reason| - should_dispatch = completion_mutex.synchronize do - next false if completed - - completed = true - - # Wake the waiting thread first, then dispatch the `notifications/cancelled` send on a separate thread. - # The wake-first ordering matters because the cancellation callback can run on the worker thread itself - # (e.g. a tool that triggers cancel from within `transport.send_request`), and a synchronous `send_notification` - # here would deadlock when the worker holds a transport-level mutex. - queue.push([:cancelled, reason]) - true - end - - next unless should_dispatch - - Thread.new do - Thread.current.report_on_exception = false - # Wait for the worker's send-boundary signal before issuing `notifications/cancelled`. Bundled transports raise - # the signal via `&on_sent` from inside `send_request`; custom transports that ignore the block still raise it - # via the worker's `ensure -> signal_sent.call`, so the loop is bounded by worker termination rather than by wall-clock time. - # The previous fixed-duration fallback could release this thread before the worker reached its send-boundary at all, - # allowing the cancel to be issued without any prior request commitment - which the spec only covers under - # the receiver's MAY-ignore-unknown-id clause and is therefore avoided here. - sent_mutex.synchronize do - sent_cond.wait(sent_mutex) until request_sent - end - cancel(request_id: request_id, reason: reason) - rescue StandardError - # Swallow notification-send failures: the calling thread has already been woken with `:cancelled` above and - # is on its way to raising `MCP::CancelledError`. - end - end - - tag, payload = queue.pop - - case tag - when :response - payload - when :error - raise payload - when :cancelled - raise MCP::CancelledError.new(request_id: request_id, reason: payload) - end - ensure - cancellation&.off_cancel(cancel_hook) if cancel_hook - end - - # Sends `notifications/cancelled` to the server for an in-flight request. - # Per spec, this is fire-and-forget: the server is expected to stop processing and suppress its response, - # with no acknowledgement returned. Driven internally by {#dispatch_with_cancellation} when a request's - # `cancellation` token fires. - def cancel(request_id:, reason: nil) - params = { requestId: request_id } - params[:reason] = reason if reason - - notification = { - jsonrpc: JsonRpcHandler::Version::V2_0, - method: Methods::NOTIFICATIONS_CANCELLED, - params: params, - } - - transport.send_notification(notification: notification) - nil - end end end diff --git a/lib/mcp/client/elicitation.rb b/lib/mcp/client/elicitation.rb deleted file mode 100644 index 52df933..0000000 --- a/lib/mcp/client/elicitation.rb +++ /dev/null @@ -1,51 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - # Client-side helpers for the `elicitation/create` server-to-client request. - # https://modelcontextprotocol.io/specification/2025-11-25/client/elicitation - module Elicitation - # Fills fields omitted from `content` with the `default` values declared in - # the elicitation request's `requestedSchema` properties, per SEP-1034. - # Provided values are never overwritten, and properties without a `default` - # are left out so the server can apply its own handling. - # Mirrors the TypeScript SDK's `applyElicitationDefaults`; the Python SDK - # applies defaults in the elicitation callback the same way this helper - # is intended to be used. - # - # @param requested_schema [Hash] The `requestedSchema` from the `elicitation/create` - # request params (string or symbol keys). - # @param content [Hash] Values already collected from the user. - # @return [Hash] `content` (string keys) with defaults filled in. - # - # @example Accept an elicitation request with all defaults - # transport.on_server_request("elicitation/create") do |params| - # { - # action: "accept", - # content: MCP::Client::Elicitation.apply_defaults(params["requestedSchema"]), - # } - # end - class << self - def apply_defaults(requested_schema, content = {}) - filled = content.to_h.transform_keys(&:to_s) - properties = requested_schema["properties"] || requested_schema[:properties] - return filled unless properties.is_a?(Hash) - - properties.each do |name, property_schema| - name = name.to_s - next if filled.key?(name) - next unless property_schema.is_a?(Hash) - - if property_schema.key?("default") - filled[name] = property_schema["default"] - elsif property_schema.key?(:default) - filled[name] = property_schema[:default] - end - end - - filled - end - end - end - end -end diff --git a/lib/mcp/client/http.rb b/lib/mcp/client/http.rb index 6969b07..24c7831 100644 --- a/lib/mcp/client/http.rb +++ b/lib/mcp/client/http.rb @@ -1,1040 +1,86 @@ # frozen_string_literal: true -require "securerandom" -require_relative "../../json_rpc_handler" -require_relative "../configuration" -require_relative "../methods" -require_relative "../protocol_deprecations" -require_relative "../version" -require_relative "mcp_param_headers" -require_relative "modern_envelope" - module MCP class Client class HTTP ACCEPT_HEADER = "application/json, text/event-stream" - SSE_ACCEPT_HEADER = "text/event-stream" - SESSION_ID_HEADER = "Mcp-Session-Id" - PROTOCOL_VERSION_HEADER = "MCP-Protocol-Version" - METHOD_HEADER = "Mcp-Method" - NAME_HEADER = "Mcp-Name" - LAST_EVENT_ID_HEADER = "Last-Event-ID" - # SEP-1699 reconnection tuning: the SSE `retry:` field from the server takes precedence; - # this default applies when the server sent none. Both values match the Python SDK - # (`DEFAULT_RECONNECTION_DELAY_MS`, `MAX_RECONNECTION_ATTEMPTS`); the TypeScript SDK uses - # an exponential backoff that the `retry:` field likewise overrides. - DEFAULT_RECONNECTION_DELAY_MS = 1000 - MAX_RECONNECTION_ATTEMPTS = 2 - - # Floor on the effective reconnection delay. `listen_for_server_requests` treats a graceful close as success - # and resets `consecutive_failures`, so `retry: 0` never reaches the attempt cap and reconnects in a tight loop. - # Waiting longer than the server asked for is explicitly allowed: the `retry` field the spec points at is - # the one defined by WHATWG HTML, whose reconnection algorithm reads "Wait a delay equal to the reconnection time - # of the event source. Optionally, wait some more." Waiting *less* is what the spec's MUST rules out, - # and nothing here ever does that. - # - # https://html.spec.whatwg.org/multipage/server-sent-events.html#reconnection-time - MIN_RECONNECTION_DELAY_MS = 100 - - # Budget in seconds for `await_response_after_disconnect`: it gates every wait between reconnection attempts, - # and whatever is left of it becomes the read timeout of each resumed stream. That method runs on the calling thread, - # so without a deadline a server answering with a large `retry:` parks a thread of the embedding application for - # as long as it likes; `MAX_RECONNECTION_ATTEMPTS` caps how many times the client reconnects, - # not how long it waits for each. A delay that would run past the deadline is not shortened - the client stops - # reconnecting instead, the same kind of decision the attempt cap already makes, so the server's `retry:` is - # always honored in full or not acted on at all. - # - # Matches `SSE_LISTENER_READ_TIMEOUT`, this client's other "how long to wait on a quiet SSE stream" value. - # `listen_for_server_requests` has no such deadline: it runs on a thread this client owns and is meant - # to poll indefinitely, so a long `retry:` there idles the SDK's own listener rather than the application. - MAX_RECONNECTION_WAIT = 300 - - # How long the standalone GET listening stream may stay idle before the read times out - # and the connection is counted as a failure and retried. Matches the Python SDK's - # `sse_read_timeout` default of 5 minutes; without this, the adapter's default read timeout - # (60 seconds for Net::HTTP) would recycle quiet streams too eagerly. - SSE_LISTENER_READ_TIMEOUT = 300 - - # Upper bound in bytes on a single JSON-RPC message from the server - an SSE event or - # a JSON response body - buffered in memory while reading a response. Without a bound, - # a server that never terminates an SSE event (or never ends a JSON body) grows - # the buffer indefinitely. Matches the 4 MiB default of `MCP::Client::Stdio::MAX_LINE_BYTES` - # and the server transports' request cap. - MAX_MESSAGE_BYTES = 4 * 1024 * 1024 - - # Upper bound on the tools whose `x-mcp-header` declarations are retained for - # `Mcp-Param-*` mirroring (SEP-2243). Past the cap, newly listed tools mirror nothing - # (the spec's guidance to send without custom headers), so a server rotating tool names across - # `tools/list` responses cannot grow the registry without bound. - MAX_MCP_PARAM_TOOLS = 1000 - - # Raised when an `oauth:` provider is paired with an MCP URL that is neither HTTPS nor - # a loopback `http://` URL, since a bearer token sent over plain HTTP to a remote host - # is trivially observed and stolen. - class InsecureURLError < ArgumentError; end - - # Faraday request middleware that compares the outgoing request URL - # against the URL snapshotted at `MCP::Client::HTTP#initialize` time. - # Registered after the user's customizer so it sees `env.url` *after* - # any custom middleware has had a chance to rewrite it - closing - # the `Faraday env.url = URI("https://attacker...")` bypass that a plain - # `client.url_prefix` check would miss. The comparison includes - # the query string, so a middleware that rewrites `env.url.query` to - # a different tenant (e.g. `?tenant=evil`) is rejected as well; otherwise - # the audience-binding check on the OAuth side could be bypassed at - # the send step. - class OAuthURLGuard - def initialize(app, expected_url:) - @app = app - @expected_url = expected_url - end - - def call(env) - effective = MCP::Client::OAuth::Discovery.canonicalize_url(env.url.to_s) - unless effective == @expected_url - # Surface the *canonicalized* form (no userinfo, no fragment) so - # credentials like `user:pass@` cannot leak into logs, stack - # traces, or exception reporters. - raise InsecureURLError, - "Effective request URL #{effective.inspect} does not match the URL " \ - "validated at initialize time (#{@expected_url.inspect}); refusing to send a bearer token." - end - @app.call(env) - end - end - - # Internal control-flow signal raised inside the streaming callback to stop reading - # an SSE stream once the awaited JSON-RPC response has arrived; servers may hold - # a stream open indefinitely (notably the standalone GET stream), so EOF cannot be relied on. - class StreamAbort < StandardError; end - private_constant :StreamAbort - - # Raised inside the streaming callback when the server sends more bytes than - # `max_message_bytes` without completing a message. Translated into - # a `RequestHandlerError` (or a listener stop) where the request context is known. - class MessageTooLargeError < StandardError; end - private_constant :MessageTooLargeError - - # Per-exchange SSE state shared between the initial POST stream and any SEP-1699 reconnection GET streams: - # the incrementally parsed JSON-RPC response, the last received SSE event id (for `Last-Event-ID`), - # and the server's `retry:` reconnection delay. Non-SSE bodies accumulate in `buffer` for the JSON path. - class SSEStream - attr_reader :buffer, :response, :last_event_id, :retry_ms - attr_accessor :abortable - - def initialize(abortable:, max_message_bytes: MAX_MESSAGE_BYTES, on_request: nil) - @abortable = abortable - @max_message_bytes = max_message_bytes - @on_request = on_request - @buffer = +"" - @parser = nil - @response = nil - @last_event_id = nil - @retry_ms = nil - end - - # Whether the server sent a SEP-1699 priming event (any event carrying an id), - # which marks the stream as resumable after a graceful close. - def primed? - !@last_event_id.nil? - end - - # Faraday `on_data` streaming callback. SSE chunks are parsed incrementally; - # anything else (JSON bodies) accumulates in `buffer`. Both paths are bounded - # by `max_message_bytes`, checked after the awaited response had its chance to - # abort the stream so an over-limit tail cannot mask a response that already arrived. - def on_data - proc do |chunk, _received_bytes, env| - if event_stream?(env) - feed(chunk) - raise StreamAbort if @abortable && @response - - if parser_buffered_bytes > @max_message_bytes - raise MessageTooLargeError, "Server SSE event exceeds #{@max_message_bytes} bytes without completing" - end - else - @buffer << chunk - - if @buffer.bytesize > @max_message_bytes - raise MessageTooLargeError, "Server response body exceeds #{@max_message_bytes} bytes" - end - end - end - end - - # A fresh parser for a new HTTP connection (reconnection GET), - # so a partial line from the previous stream cannot corrupt the next one. - def reset_parser! - @parser = nil - end - - # Parses an SSE body that was delivered outside the streaming callback: - # Faraday versions that do not pass `env` to `on_data` leave SSE chunks in `buffer` - # (consumed here so they are not parsed twice), and adapters without `on_data` support - # yield the whole body only via `fallback_body` (the Faraday `response.body`). - def ingest_pending!(fallback_body) - text = @buffer.empty? ? fallback_body : @buffer.slice!(0..-1) - feed(text) if text.is_a?(String) && !text.empty? - end - - private - - def event_stream?(env) - headers = env&.response_headers - content_type = headers && (headers["content-type"] || headers["Content-Type"]) - !!content_type&.include?("text/event-stream") - end - - def feed(chunk) - parser.feed(chunk) do |_type, data, id, reconnection_time| - @last_event_id = id if id && !id.empty? - @retry_ms = reconnection_time if reconnection_time - next if data.nil? || data.empty? - - begin - parsed = JSON.parse(data) - rescue JSON::ParserError - next - end - - next unless parsed.is_a?(Hash) - - if parsed.key?("result") || parsed.key?("error") - @response ||= parsed - elsif parsed["method"] && parsed.key?("id") - # A server-to-client request (e.g. `elicitation/create`) delivered - # on the stream while the original request is still pending. - @on_request&.call(parsed) - end - end - end - - # Bytes the parser has buffered for a not-yet-dispatched event: the partial line - # and the accumulated `data:` field values (plus the small event type and last event id buffers). - # External byte counting cannot tell consumed-and-discarded bytes (comments, field names, delimiters) - # from consumed-and-retained ones, so the parser's own String buffers are measured instead; - # summing every String instance variable keeps the measurement valid if the parser renames or adds buffers. - # A parser rewrite that buffered elsewhere would make this return 0 and quietly lift the cap - - # the regression tests feeding an over-limit event guard against that. - def parser_buffered_bytes - parser.instance_variables.sum do |name| - value = parser.instance_variable_get(name) - value.is_a?(String) ? value.bytesize : 0 - end - end - - def parser - @parser ||= begin - require "event_stream_parser" - EventStreamParser::Parser.new - rescue LoadError - raise LoadError, "The 'event_stream_parser' gem is required to parse SSE responses. " \ - "Add it to your Gemfile: gem 'event_stream_parser', '>= 1.0'. " \ - "See https://rubygems.org/gems/event_stream_parser for more details." - end - end - end - private_constant :SSEStream - - attr_reader :url, :session_id, :protocol_version, :server_info, :oauth - - def initialize( - url:, - headers: {}, - oauth: nil, - max_message_bytes: MAX_MESSAGE_BYTES, - max_reconnection_wait: MAX_RECONNECTION_WAIT, - &block - ) - # `nil` or a non-positive value would make the buffering unbounded and silently - # disable the protection, so reject it up front. - unless max_message_bytes.is_a?(Integer) && max_message_bytes > 0 - raise ArgumentError, "max_message_bytes must be a positive Integer" - end - - unless max_reconnection_wait.is_a?(Numeric) && max_reconnection_wait > 0 - raise ArgumentError, "max_reconnection_wait must be a positive number" - end - - if oauth && !MCP::Client::OAuth::Discovery.secure_url?(url) - # Mask credentials (userinfo) and query parameters before quoting the URL in the error message - # so they cannot leak into logs. - safe_url = MCP::Client::OAuth::Discovery.canonicalize_origin_and_path(url) - raise InsecureURLError, - "MCP URL #{safe_url.inspect} must use https or be a loopback http URL when an oauth provider is set; " \ - "sending bearer tokens over plain http to a remote host would leak them on the wire." - end + attr_reader :url + def initialize(url:, headers: {}) @url = url @headers = headers - @faraday_customizer = block - @oauth = oauth - @max_message_bytes = max_message_bytes - @max_reconnection_wait = max_reconnection_wait - # Snapshot the canonical URL at construction time. This single value - # serves two related roles, both of which need to see the query string: - # - # - As the RFC 8707 `resource` claim sent on the authorization and - # token requests (and as the base for PRM discovery URLs) - - # matching the TS / Python SDKs' `resourceUrlFromServerUrl` / - # `resource_url_from_server_url` so multi-tenant servers that scope - # by `?tenant=...` round-trip correctly. - # - As the comparison value for the URL guard middleware. Comparing - # query strings as well as origin + path is required so a Faraday - # middleware that rewrites `env.url.query` to a different tenant - # cannot send the bearer token to the wrong audience while - # the resource binding on the OAuth side stays correct. - # - # Saved only when `oauth:` is set so non-OAuth transports keep their - # existing behavior. - @oauth_server_url = oauth ? MCP::Client::OAuth::Discovery.canonicalize_url(url) : nil - @session_id = nil - @protocol_version = nil - @server_info = nil - @connected = false - @server_request_handlers = {} - @listener_thread = nil - @modern_client_info = nil - @modern_capabilities = nil - @mcp_param_declarations = {} end - # Registers a handler for a server-to-client request (e.g. `elicitation/create`) delivered on an SSE stream. - # The handler receives the request's `params` (a Hash with string keys, possibly empty) and its return value is - # sent back to the server as the JSON-RPC `result`. - # The handler may raise `MCP::Client::ServerRequestError` to answer with a specific JSON-RPC error code. - # Requests for methods without a registered handler are answered with a JSON-RPC "method not found" (-32601) error. - # Registering a handler opens a standalone GET SSE listening stream (once connected), since servers send requests - # that are not tied to a client request on that stream - matching the TypeScript and Python SDK clients, - # which start listening after the `initialize` handshake. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#listening-for-messages-from-the-server - def on_server_request(method, &handler) - raise ArgumentError, "A handler block is required" unless handler - - @server_request_handlers[method.to_s] = handler - start_listening if connected? - end - - # Performs the MCP `initialize` handshake: sends an `initialize` request - # followed by the required `notifications/initialized` notification. - # The server's `InitializeResult` (protocol version, capabilities, server - # info, instructions) is cached on the transport and returned. - # - # Idempotent: a second call returns the cached `InitializeResult` without - # contacting the server. After `close`, state is cleared and `connect` - # will handshake again. - # - # @param client_info [Hash, nil] `{ name:, version: }` identifying the client. - # Defaults to `{ name: "mcp-ruby-client", version: MCP::VERSION }`. - # @param protocol_version [String, nil] Protocol version to offer on the legacy handshake. - # Defaults to `MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION`; a modern version - # raises `ArgumentError` here (modern versions are selected via `mode: :modern`/`:auto`). - # @param capabilities [Hash] Capabilities advertised by the client. Defaults to `{}`. - # @return [Hash] The server's `InitializeResult`. - # @raise [RequestHandlerError] If the server responds with a JSON-RPC error - # or a malformed result. - # @param mode [Symbol] Lifecycle selection (SEP-2575): `:legacy` (default) performs - # the handshake below, `:modern` skips it and probes `server/discover`, - # and `:auto` probes `server/discover` first, falling back to the legacy handshake - # when the server does not serve a mutually supported modern version. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#initialization - def connect(client_info: nil, protocol_version: nil, capabilities: {}, mode: :legacy) - return @server_info if connected? - - # Per the SEP-2575 era model, a modern version cannot ride the legacy `initialize` handshake. - MCP::Configuration.reject_modern_handshake_version!(protocol_version) if mode == :legacy - - client_info ||= { name: "mcp-ruby-client", version: MCP::VERSION } - - case mode - when :legacy - connect_legacy(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - when :modern - connect_modern(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - when :auto - connect_auto(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - else - raise ArgumentError, "mode must be :legacy, :modern, or :auto" - end - end - - # Whether the transport operates in the stateless modern lifecycle (SEP-2575): - # no handshake was performed and every request carries the `_meta` envelope. - def modern? - !@modern_client_info.nil? - end - - # Returns true once `connect` has completed the full handshake - # (`initialize` response received and `notifications/initialized` sent), - # or once the modern lifecycle was adopted via `server/discover`. - # Returns false before the first handshake and after `close`. - def connected? - @connected - end - - # Sends a JSON-RPC request and returns the parsed response body. - # After a successful `initialize` handshake, the session ID and protocol version returned by - # the server are captured and automatically included on subsequent requests. - # - # If a block is given, it is invoked just before Faraday's `post` is called. - # Faraday's synchronous `post` does not expose a post-write / pre-response hook, - # so this is the latest send-boundary signal the adapter exposes; the actual TCP write happens - # inside `post`. `MCP::Client#dispatch_with_cancellation` uses this yield to release - # the cancel-dispatch thread, which then issues a separate `notifications/cancelled` POST - # that may overlap with the original request on the network. The spec covers this: - # the sender has issued the request and still believes it in-progress, and receivers MAY ignore - # a cancellation referring to an unknown request id when the cancel POST happens to arrive first. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/cancellation def send_request(request:) - # Modern requests (never notifications, whose `_meta` has no envelope) carry - # the SEP-2575 triple; the `MCP-Protocol-Version` header from `session_headers` - # matches it by construction. - if modern? && (request[:id] || request["id"]) - request = ModernEnvelope.stamp( - request, - protocol_version: @protocol_version, - client_info: @modern_client_info, - capabilities: @modern_capabilities, - ) - end - method = request[:method] || request["method"] params = request[:params] || request["params"] - oauth_retried = false - step_up_retried = false - begin - # The response is consumed incrementally so that an SSE stream the server holds open - # (or closes early per SEP-1699) can be handled; `initialize` streams are read to EOF - # so the response object (and its `Mcp-Session-Id` header) is always available for capture. - stream = SSEStream.new( - abortable: method.to_s != MCP::Methods::INITIALIZE, - max_message_bytes: @max_message_bytes, - on_request: ->(message) { dispatch_server_request(message) }, - ) - - yield if block_given? - - response = begin - client.post("", request, session_headers.merge(request_metadata_headers(method, params))) do |req| - req.options.on_data = stream.on_data - end - rescue StreamAbort - nil - end - - body = resolve_response_body(stream, response, method, params) - - capture_session_info(method, response, body) if response - capture_mcp_param_declarations(method, params, body) - - body - rescue MessageTooLargeError => e - raise RequestHandlerError.new( - e.message, - { method: method, params: params }, - error_type: :internal_error, - ) - rescue Faraday::BadRequestError => e - raise RequestHandlerError.new( - "The #{method} request is invalid", - { method: method, params: params }, - error_type: :bad_request, - original_error: e, - ) - rescue Faraday::UnauthorizedError => e - # Run the OAuth flow at most once per `send_request` invocation. - # The `oauth_retried` flag lives outside the `begin` so it survives `retry`, - # ensuring a server returning 401 indefinitely raises rather than loops. - if @oauth && !oauth_retried - oauth_retried = true - run_oauth_flow!(unauthorized_error: e) - retry - end - - raise RequestHandlerError.new( - "You are unauthorized to make #{method} requests", - { method: method, params: params }, - error_type: :unauthorized, - original_error: e, - ) - rescue Faraday::ForbiddenError => e - # OAuth 2.0 step-up: a 403 carrying `error="insufficient_scope"` in - # the Bearer challenge means the existing access token is valid - # but lacks scopes the server now requires for this operation. - # Re-run the full authorization flow with the escalated scope from - # the challenge and retry once. A plain 403 without the challenge is - # surfaced unchanged. - if @oauth && !step_up_retried && insufficient_scope_challenge?(e) - step_up_retried = true - run_step_up_flow!(forbidden_error: e) - - retry - end - - raise RequestHandlerError.new( - "You are forbidden to make #{method} requests", - { method: method, params: params }, - error_type: :forbidden, - original_error: e, - ) - rescue Faraday::ResourceNotFound => e - # Per spec, 404 is the session-expired signal only when the request - # actually carried an `Mcp-Session-Id`. A 404 without a session attached - # (e.g. wrong URL or a stateless server) surfaces as a generic not-found. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#session-management - if @session_id - clear_session - raise SessionExpiredError.new( - "The #{method} request is not found", - { method: method, params: params }, - original_error: e, - ) - else - raise RequestHandlerError.new( - "The #{method} request is not found", - { method: method, params: params }, - error_type: :not_found, - original_error: e, - ) - end - rescue Faraday::UnprocessableEntityError => e - raise RequestHandlerError.new( - "The #{method} request is unprocessable", - { method: method, params: params }, - error_type: :unprocessable_entity, - original_error: e, - ) - rescue Faraday::Error => e - raise RequestHandlerError.new( - "Internal error handling #{method} request", - { method: method, params: params }, - error_type: :internal_error, - original_error: e, - ) - end - end - - # Sends a JSON-RPC notification (no response expected). Used by `Client#cancel` to deliver - # `notifications/cancelled` for an in-flight request. The server acknowledges with HTTP 202 Accepted - # per the Streamable HTTP spec. - def send_notification(notification:) - method = notification[:method] || notification["method"] - - client.post("", notification, session_headers) - nil - rescue Faraday::Error => e + response = client.post("", request) + validate_response_content_type!(response, method, params) + response.body + rescue Faraday::BadRequestError => e raise RequestHandlerError.new( - "Failed to send #{method} notification", - { method: method }, + "The #{method} request is invalid", + { method: method, params: params }, + error_type: :bad_request, + original_error: e, + ) + rescue Faraday::UnauthorizedError => e + raise RequestHandlerError.new( + "You are unauthorized to make #{method} requests", + { method: method, params: params }, + error_type: :unauthorized, + original_error: e, + ) + rescue Faraday::ForbiddenError => e + raise RequestHandlerError.new( + "You are forbidden to make #{method} requests", + { method: method, params: params }, + error_type: :forbidden, + original_error: e, + ) + rescue Faraday::ResourceNotFound => e + raise RequestHandlerError.new( + "The #{method} request is not found", + { method: method, params: params }, + error_type: :not_found, + original_error: e, + ) + rescue Faraday::UnprocessableEntityError => e + raise RequestHandlerError.new( + "The #{method} request is unprocessable", + { method: method, params: params }, + error_type: :unprocessable_entity, + original_error: e, + ) + rescue Faraday::Error => e # Catch-all + raise RequestHandlerError.new( + "Internal error handling #{method} request", + { method: method, params: params }, error_type: :internal_error, original_error: e, ) end - # Terminates the session by sending an HTTP DELETE to the MCP endpoint - # with the current `Mcp-Session-Id` header, and clears locally tracked - # session state afterward. No-op when no session has been established. - # - # Per spec, the server MAY respond with HTTP 405 Method Not Allowed when - # it does not support client-initiated termination, and returns 404 for - # a session it has already terminated. Both mean the session is gone — - # the desired end state. Other errors surface to the caller; local - # session state is cleared either way. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#session-management - def close - unless @session_id - clear_session - return - end - - begin - client.delete("", nil, session_headers) - rescue Faraday::ClientError => e - raise unless [404, 405].include?(e.response&.dig(:status)) - ensure - clear_session - end - end - private attr_reader :headers - def connect_legacy(client_info:, protocol_version:, capabilities:) - protocol_version ||= MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION - - response = send_request(request: { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: SecureRandom.uuid, - method: MCP::Methods::INITIALIZE, - params: { - protocolVersion: protocol_version, - capabilities: capabilities, - clientInfo: client_info, - }, - }) - - if response.is_a?(Hash) && response.key?("error") - clear_session - error = response["error"] - raise RequestHandlerError.new( - "Server initialization failed: #{error["message"]}", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - unless response.is_a?(Hash) && response["result"].is_a?(Hash) - clear_session - raise RequestHandlerError.new( - "Server initialization failed: missing result in response", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - @server_info = response["result"] - negotiated_protocol_version = @server_info["protocolVersion"] - # A modern version in an `InitializeResult` is rejected along with unknown ones: the handshake - # settles on a legacy version by definition, and the TypeScript and Python clients refuse - # a modern counter-offer the same way. - unless MCP::Configuration::SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS.include?(negotiated_protocol_version) - clear_session - raise RequestHandlerError.new( - "Server initialization failed: unsupported protocol version #{negotiated_protocol_version.inspect}", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - begin - send_request(request: { - jsonrpc: JsonRpcHandler::Version::V2_0, - method: MCP::Methods::NOTIFICATIONS_INITIALIZED, - }) - rescue StandardError - clear_session - raise - end - - @connected = true - start_listening if @server_request_handlers.any? - @server_info - end - - # Enters the modern lifecycle by probing `server/discover` at the requested (or latest) modern version. - # No `initialize` or `notifications/initialized` is sent; the probe response becomes `server_info`. - def connect_modern(client_info:, protocol_version:, capabilities:) - version = protocol_version || MCP::Configuration::LATEST_MODERN_PROTOCOL_VERSION - unless MCP::Configuration.modern_protocol_version?(version) - raise ArgumentError, "protocol_version #{version.inspect} is not a supported modern protocol version" - end - - enter_modern_mode(protocol_version: version, client_info: client_info, capabilities: capabilities) - - begin - result = probe_discover - rescue StandardError - leave_modern_mode - raise - end - - supported = result["supportedVersions"] - unless supported.is_a?(Array) && supported.include?(version) - leave_modern_mode - raise RequestHandlerError.new( - "Server discovery failed: no mutually supported modern protocol version " \ - "(server supports #{supported.inspect})", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - # SEP-2577 deprecates roots and sampling at 2026-07-28, the revision every modern connection speaks, - # so the warning lives here now that the handshake cannot land on one. - MCP::ProtocolDeprecations.warn_for_client_capabilities(capabilities, protocol_version: version, uplevel: 1) - - @server_info = result - @connected = true - @server_info - end - - # Probes `server/discover` and adopts the modern lifecycle when the server serves - # a mutually supported modern version; otherwise falls back to the legacy handshake. - # The fallback intentionally covers a successful discovery without a mutual modern - # version as well: during the 2026-07-28 rollout a server may answer discovery while - # only serving legacy versions. - def connect_auto(client_info:, protocol_version:, capabilities:) - modern_pin = protocol_version if protocol_version && MCP::Configuration.modern_protocol_version?(protocol_version) - connect_modern(client_info: client_info, protocol_version: modern_pin, capabilities: capabilities) - rescue RequestHandlerError - # An explicitly requested modern version is never downgraded by the fallback: the legacy handshake cannot negotiate it, - # so the probe's failure is the real answer and propagates. - raise if modern_pin - - connect_legacy(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - end - - def enter_modern_mode(protocol_version:, client_info:, capabilities:) - @modern_client_info = client_info - @modern_capabilities = capabilities || {} - # `session_headers` sends `@protocol_version` as the `MCP-Protocol-Version` header, - # which the modern lifecycle requires to match the `_meta`-carried version. - @protocol_version = protocol_version - end - - def leave_modern_mode - @modern_client_info = nil - @modern_capabilities = nil - @protocol_version = nil - end - - def probe_discover - response = send_request(request: { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: SecureRandom.uuid, - method: MCP::Methods::SERVER_DISCOVER, - }) - - if response.is_a?(Hash) && response.key?("error") - error = response["error"] - raise RequestHandlerError.new( - "Server discovery failed: #{error["message"]}", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - result = response.is_a?(Hash) ? response["result"] : nil - unless result.is_a?(Hash) - raise RequestHandlerError.new( - "Server discovery failed: missing result in response", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - result - end - def client require_faraday! @client ||= Faraday.new(url) do |faraday| faraday.request(:json) - # The client parses response bodies itself (`resolve_response_body`), so streamed and buffered responses - # take the same path; Faraday's json response middleware is deliberately left out. + faraday.response(:json) faraday.response(:raise_error) faraday.headers["Accept"] = ACCEPT_HEADER headers.each do |key, value| faraday.headers[key] = value end - - @faraday_customizer&.call(faraday) - - # Register the URL identity guard *after* the user's customizer - # so it sits closest to the adapter in the request stack. That way - # the guard sees `env.url` after any customizer-added middleware has had - # a chance to rewrite it, closing the `env.url = URI("https://...")` - # bypass that a `Faraday::Connection#url_prefix` check cannot detect. - faraday.use(OAuthURLGuard, expected_url: @oauth_server_url) if @oauth_server_url end end - # Per spec, the client MUST include `MCP-Session-Id` (when the server assigned one) - # and `MCP-Protocol-Version` on all requests after `initialize`. - # - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#session-management - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#protocol-version-header - def session_headers - request_headers = {} - request_headers[SESSION_ID_HEADER] = @session_id if @session_id - request_headers[PROTOCOL_VERSION_HEADER] = @protocol_version if @protocol_version - if @oauth && (token = @oauth.access_token) - request_headers["Authorization"] = "Bearer #{token}" - end - request_headers - end - - # Per SEP-2243, mirror the JSON-RPC method and target name/uri into HTTP headers so intermediaries - # can route and inspect requests without parsing the body. `Mcp-Name` comes from `params.name` - # (tools, prompts) or, when absent, `params.uri` (resources). - # - # https://modelcontextprotocol.io/specification/draft/basic/transports/streamable-http#request-metadata - def request_metadata_headers(method, params) - return {} unless method - - metadata_headers = { METHOD_HEADER => method } - if params.is_a?(Hash) - name = params[:name] || params["name"] - name = params[:uri] || params["uri"] unless name.is_a?(String) - metadata_headers[NAME_HEADER] = encode_header_value(name) if name.is_a?(String) - - if method == MCP::Methods::TOOLS_CALL && (declarations = @mcp_param_declarations[params[:name] || params["name"]]) - arguments = params[:arguments] || params["arguments"] - - metadata_headers.merge!(McpParamHeaders.build(declarations, arguments)) - end - end - - metadata_headers - end - - # Learns the `x-mcp-header` declarations of the tools a `tools/list` response advertises, - # so later `tools/call` requests can mirror the annotated arguments into `Mcp-Param-*` headers (SEP-2243). - # The custom headers exist on the modern lifecycle only, matching the TypeScript and Python SDKs, - # so legacy connections learn nothing. Only a valid, non-empty declaration set is kept: - # an invalid tool definition mirrors nothing, - # following the spec's guidance to send without custom headers when no reliable declarations are available. - def capture_mcp_param_declarations(method, params, body) - return unless modern? - return unless method.to_s == MCP::Methods::TOOLS_LIST && body.is_a?(Hash) - - tools = body.dig("result", "tools") - return unless tools.is_a?(Array) - - # An uncursored request answered without `nextCursor` is the complete tool universe, - # so knowledge about unlisted tools is stale; the registry is rebuilt from this listing, - # the same pruning the Python SDK applies to complete listings. - cursor = params.is_a?(Hash) && (params[:cursor] || params["cursor"]) - complete = !cursor && body.dig("result", "nextCursor").nil? - registry = complete ? {} : @mcp_param_declarations - - tools.each do |tool| - next unless tool.is_a?(Hash) - - name = tool["name"] - next unless name.is_a?(String) - - scan = McpParamHeaders.scan(tool["inputSchema"]) - if scan[:valid] && !scan[:declarations].empty? - next if !registry.key?(name) && registry.size >= MAX_MCP_PARAM_TOOLS - - registry[name] = scan[:declarations] - else - registry.delete(name) - end - end - - @mcp_param_declarations = registry if complete - end - - # A header value that is not safe to transmit as-is - non-ASCII, control characters (including CR/LF, - # which would otherwise allow header injection), or significant leading/trailing whitespace - is wrapped as - # `=?base64??=`. Safe ASCII values are sent unchanged. - def encode_header_value(value) - return value if safe_header_value?(value) - - "=?base64?#{[value].pack("m0")}?=" - end - - def safe_header_value?(value) - value.bytes.all? { |byte| byte.between?(0x20, 0x7e) } && - (value.empty? || (!value.start_with?(" ", "\t") && !value.end_with?(" ", "\t"))) && - !(value.start_with?("=?base64?") && value.end_with?("?=")) - end - - # Drives the OAuth orchestrator on a 401 from the MCP endpoint. - # The `WWW-Authenticate` header (when present) supplies the `resource_metadata` - # URL and an optional `scope` challenge per RFC 9728 Section 5.1. - # - # If the provider already holds a refresh token, we try to exchange it - # for a fresh access token first; only when that fails (e.g., the refresh token was revoked) - # do we fall back to the full Authorization Code + PKCE + DCR flow. - # - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#error-handling - def run_oauth_flow!(unauthorized_error:) - params = parse_www_authenticate_from_error(unauthorized_error) - flow = MCP::Client::OAuth::Flow.new(provider: @oauth) - return if attempt_refresh(flow: flow, resource_metadata_url: params["resource_metadata"]) - - run_full_authorization_flow!(flow: flow, params: params) - end - - # Drives a full Authorization Code + PKCE flow without first attempting - # to refresh the access token. Used for the MCP scope-selection-strategy - # step-up path: the provider already holds a valid access token, - # but the server returned a 403 with - # `WWW-Authenticate: ... error="insufficient_scope", scope="..."` - # per RFC 6750 Section 3.1. Refreshing the existing token would re-issue - # the same scope set the server already rejected, so the SDK must run - # a fresh authorization request. The request asks for the union of - # the currently granted scope and the newly demanded scope; otherwise - # the caller would lose previously held scopes and trigger another step-up - # on the next operation that needs them. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#scope-selection-strategy - def run_step_up_flow!(forbidden_error:) - params = parse_www_authenticate_from_error(forbidden_error) - flow = MCP::Client::OAuth::Flow.new(provider: @oauth) - params = params.merge("scope" => escalated_step_up_scope(params["scope"])) - - run_full_authorization_flow!(flow: flow, params: params) - end - - # Returns the space-separated union of the currently granted scope (read - # from the stored token response per RFC 6749 Section 5.1) and the scope - # demanded by the step-up challenge. Duplicates are collapsed; order - # follows first appearance so existing scopes precede the newly added - # ones. Returns `nil` when neither side carries a scope so - # `build_authorization_url` omits the `scope` parameter entirely. - def escalated_step_up_scope(challenge_scope) - tokens = @oauth.tokens - granted = tokens.is_a?(Hash) ? (tokens["scope"] || tokens[:scope]) : nil - scopes = [granted, challenge_scope].compact.flat_map { |scope| scope.to_s.split }.uniq - - scopes.empty? ? nil : scopes.join(" ") - end - - # True when the response on `forbidden_error` carries a Bearer challenge - # with `error="insufficient_scope"` per RFC 6750 Section 3.1 and the MCP - # scope-selection-strategy section. A 403 without that signal is not a - # step-up challenge and must not trigger re-authorization. - def insufficient_scope_challenge?(forbidden_error) - parse_www_authenticate_from_error(forbidden_error)["error"] == "insufficient_scope" - end - - def parse_www_authenticate_from_error(error) - response = error.response || {} - response_headers = response[:headers] || {} - header = response_headers["www-authenticate"] || response_headers["WWW-Authenticate"] - MCP::Client::OAuth::Discovery.parse_www_authenticate(header) - end - - def run_full_authorization_flow!(flow:, params:) - # Use the URL snapshotted at `initialize` time so a post-construction - # mutation of `@url` cannot redirect PRM/AS discovery and the authorize - # URL to an attacker-controlled host. - flow.run!( - server_url: @oauth_server_url, - resource_metadata_url: params["resource_metadata"], - scope: params["scope"], - ) - end - - # Tries to swap a saved `refresh_token` for a fresh access token. Returns truthy - # on success and falsy on either "no refresh token available" or "refresh attempt failed" - # (in which case the caller should run the full interactive flow). - def attempt_refresh(flow:, resource_metadata_url:) - return false unless refresh_token_available? - - # Use the snapshotted URL for the same reason as `run_oauth_flow!` above: - # post-construction `@url` mutation must not redirect token-refresh - # discovery to an attacker-controlled host. Use the query-bearing form - # so the refresh request's RFC 8707 `resource` claim matches - # the original authorization request. - flow.refresh!(server_url: @oauth_server_url, resource_metadata_url: resource_metadata_url) - true - rescue MCP::Client::OAuth::Flow::InvalidGrantError - # The refresh token has been revoked or expired by the AS. Wipe it so - # the full interactive flow runs fresh on the retry. - @oauth.clear_tokens! - false - rescue MCP::Client::OAuth::Flow::AuthorizationError - # Transient failure (network, 5xx, AS metadata, etc.). Leave the refresh - # token in place; the next attempt may succeed and we avoid forcing - # the user through an interactive reauth for a recoverable error. - false - end - - def refresh_token_available? - tokens = @oauth.tokens - return false unless tokens.is_a?(Hash) - - !(tokens["refresh_token"] || tokens[:refresh_token]).to_s.empty? - end - - def capture_session_info(method, response, body) - return unless method.to_s == Methods::INITIALIZE - - # Faraday normalizes header names to lowercase. - session_id = response.headers[SESSION_ID_HEADER.downcase] - @session_id ||= session_id unless session_id.to_s.empty? - @protocol_version ||= body.is_a?(Hash) ? body.dig("result", "protocolVersion") : nil - end - - def clear_session - stop_listening - @session_id = nil - @protocol_version = nil - @server_info = nil - @connected = false - @modern_client_info = nil - @modern_capabilities = nil - end - - # Opens the standalone GET SSE listening stream on a background thread so server-to-client requests - # can arrive while the main thread is blocked on its own request (e.g. a tools/call awaiting elicitation). - # Like the TypeScript and Python SDK clients, the GET is fired without waiting for it to be established. - def start_listening - return if @listener_thread&.alive? - - @listener_thread = Thread.new { listen_for_server_requests } - end - - def stop_listening - @listener_thread&.kill - @listener_thread = nil - end - - # Reconnection semantics match the TypeScript and Python SDK clients: a stream that was established and - # then closed gracefully is retried indefinitely after the server's `retry:` interval (SSE semantics), - # while consecutive connection failures - HTTP errors and idle read timeouts both count - stop the listener - # once they reach `MAX_RECONNECTION_ATTEMPTS`; a successful stream in between resets the count. - # A 405 stops immediately without retrying, since it is the spec's answer from a server that offers no listening stream. - def listen_for_server_requests - stream = SSEStream.new( - abortable: false, - max_message_bytes: @max_message_bytes, - on_request: ->(message) { dispatch_server_request(message) }, - ) - consecutive_failures = 0 - - loop do - begin - client.get("") do |request| - request.headers.update(session_headers) - request.headers["Accept"] = SSE_ACCEPT_HEADER - request.headers[LAST_EVENT_ID_HEADER] = stream.last_event_id if stream.last_event_id - request.options.read_timeout = SSE_LISTENER_READ_TIMEOUT - request.options.on_data = stream.on_data - end - - consecutive_failures = 0 - rescue MessageTooLargeError - # Reconnecting would let the server stream the same over-limit event again, so stop listening instead of retrying. - break - rescue Faraday::Error => e - break if e.response&.dig(:status) == 405 - - consecutive_failures += 1 - - break if consecutive_failures >= MAX_RECONNECTION_ATTEMPTS - end - - stream.reset_parser! - - sleep(reconnection_delay_seconds(stream)) - end - end - - # The reconnection delay in seconds: the server's `retry:` value when it sent one and - # the default otherwise, never shortened, raised to `MIN_RECONNECTION_DELAY_MS` when the server - # asked for less than that. A `retry:` that is negative or not a run of digits is not a value at all; - # the SSE parser drops it, so those arrive here as the default rather than as something to guard. - def reconnection_delay_seconds(stream) - delay_ms = stream.retry_ms || DEFAULT_RECONNECTION_DELAY_MS - - [delay_ms, MIN_RECONNECTION_DELAY_MS].max / 1000.0 - end - - # Seconds left before `deadline`, floored just above zero so a budget consumed down to the last instant - # still asks the adapter for a timeout rather than for "no timeout". - def remaining_reconnection_budget(deadline) - [deadline - Process.clock_gettime(Process::CLOCK_MONOTONIC), 0.001].max - end - def require_faraday! require "faraday" rescue LoadError @@ -1043,189 +89,14 @@ module MCP "See https://rubygems.org/gems/faraday for more details." end - # Determines the logical JSON-RPC body of the exchange after the POST stream finished - # (or was aborted because the response already arrived). - def resolve_response_body(stream, response, method, params) - return stream.response if stream.response - - # 202 Accepted is the server's ACK for a JSON-RPC notification or response; no body is expected. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#sending-messages-to-the-server - return if response.status == 202 - + def validate_response_content_type!(response, method, params) content_type = response.headers["Content-Type"] - - if content_type&.include?("text/event-stream") - # Nothing was parsed during streaming: either the adapter does not support `on_data` - # (the whole body sits in `response.body`) or Faraday did not pass `env` to `on_data` - # (Faraday < 2.1; the SSE chunks sit in `buffer`). Parse whichever holds the body. - unless stream.primed? - stream.ingest_pending!(response.body) - return stream.response if stream.response - end - - # SEP-1699: a graceful close after a priming event (an event with an id) but before - # the response means "reconnect via GET to resume". - return await_response_after_disconnect(stream, method, params) if stream.primed? - - raise RequestHandlerError.new( - "No valid JSON-RPC response found in SSE stream", - { method: method, params: params }, - error_type: :parse_error, - ) - elsif content_type&.include?("application/json") - return parse_json_buffer(stream.buffer, method, params) unless stream.buffer.empty? - - # Adapters without `on_data` support deliver the body via `response.body`; a JSON middleware - # added by the Faraday customizer may have parsed it already. - response.body.is_a?(String) ? parse_json_buffer(response.body, method, params) : response.body - else - raise RequestHandlerError.new( - "Unsupported Content-Type: #{content_type.inspect}. Expected application/json or text/event-stream.", - { method: method, params: params }, - error_type: :unsupported_media_type, - ) - end - end - - # Answers a server-to-client request received on an SSE stream by invoking the handler registered via - # `on_server_request` and POSTing its return value back as a JSON-RPC response; the server ACKs with - # 202 Accepted. Requests without a registered handler are answered with a "method not found" error. - # A handler may raise `ServerRequestError` to answer with a specific JSON-RPC error code - # (e.g. `-1` for a rejected sampling request); any other error is answered with an "internal error". - # In every case the server is not left waiting, matching how the TypeScript and Python SDKs convert handler - # failures into JSON-RPC error responses. - def dispatch_server_request(message) - handler = @server_request_handlers[message["method"]] - response = if handler - begin - { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: message["id"], - result: handler.call(message["params"] || {}), - } - rescue ServerRequestError => e - { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: message["id"], - error: { code: e.code, message: e.message }, - } - rescue StandardError => e - { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: message["id"], - error: { - code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - message: "Internal error handling #{message["method"]} request: #{e.message}", - }, - } - end - elsif message["method"] == MCP::Methods::PING && (message["id"].is_a?(String) || message["id"].is_a?(Numeric)) - # The ping receiver "MUST respond promptly with an empty response" (MCP ping utility), - # so an unhandled ping is answered with the empty result rather than Method not found. - # A JSON-RPC id is a String or a Number; the reference SDKs reject other shapes at - # schema validation, so a ping carrying one falls through to Method not found instead. - # The default lives here instead of in `@server_request_handlers`, whose `any?` opens - # the GET listening stream on connect: a built-in pong must not change listener behavior. - # A handler registered via `on_server_request("ping")` still wins through the branch above. - { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: message["id"], - result: {}, - } - else - { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: message["id"], - error: { - code: JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, - message: "Method not found: #{message["method"]}", - }, - } - end - - send_client_response(response) - end - - def send_client_response(response) - client.post("", response, session_headers) - end - - def parse_json_buffer(buffer, method, params) - return if buffer.empty? - - JSON.parse(buffer) - rescue JSON::ParserError => e - raise RequestHandlerError.new( - "Failed to parse JSON response: #{e.message}", - { method: method, params: params }, - error_type: :parse_error, - ) - end - - # SEP-1699 resumability: the server closed the SSE stream after a priming event - # without delivering the response. Treat the graceful close like a network failure: - # wait the `retry:` interval the server asked for (default 1000ms), then reconnect with - # a GET carrying `Last-Event-ID` so the server can replay the pending response on - # the standalone stream. Mirrors the TypeScript SDK's `StreamableHTTPClientTransport` - # reconnection and the Python SDK's `_handle_reconnection` (including its 2-attempt cap). - # - # This runs on the caller's thread, so the attempts are bounded by `max_reconnection_wait` as well as - # by their count: the deadline gates each wait, and what is left of it becomes the read timeout of - # the resumed stream. A delay that would run past the deadline is never shortened: the client stops - # reconnecting instead, so the server's `retry:` is honored in full or not acted on at all. - # https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1699 - def await_response_after_disconnect(stream, method, params) - stream.abortable = true - deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + @max_reconnection_wait - gave_up_waiting = false - - MAX_RECONNECTION_ATTEMPTS.times do - delay = reconnection_delay_seconds(stream) - if Process.clock_gettime(Process::CLOCK_MONOTONIC) + delay > deadline - gave_up_waiting = true - break - end - - sleep(delay) - stream.reset_parser! - - # Bound the resumed stream's idle time by what is left of the budget, rather than leaving it to - # whatever the Faraday adapter defaults to. `listen_for_server_requests` guards its own GET the same way; - # without this, a caller-supplied adapter with no default read timeout would let a server hold - # the connection open past the budget by simply sending nothing. - read_timeout = remaining_reconnection_budget(deadline) - - reconnect_response = begin - client.get("") do |req| - req.headers.update(session_headers) - req.headers["Accept"] = SSE_ACCEPT_HEADER - req.headers[LAST_EVENT_ID_HEADER] = stream.last_event_id if stream.last_event_id - req.options.read_timeout = read_timeout - req.options.on_data = stream.on_data - end - rescue StreamAbort - # The awaited response arrived on the reconnected stream. - nil - end - - # Same fallback as `resolve_response_body` for adapters that do not stream via `on_data`. - if reconnect_response && stream.response.nil? - stream.ingest_pending!(reconnect_response.body) - end - - return stream.response if stream.response - end - - reason = if gave_up_waiting - "the reconnection delay it asked for would exceed the #{@max_reconnection_wait} second reconnection budget" - else - "#{MAX_RECONNECTION_ATTEMPTS} reconnection attempts" - end + return if content_type&.include?("application/json") raise RequestHandlerError.new( - "Server closed the SSE stream without a response for #{method} after #{reason}", + "Unsupported Content-Type: #{content_type.inspect}. This client only supports JSON responses.", { method: method, params: params }, - error_type: :internal_error, + error_type: :unsupported_media_type, ) end end diff --git a/lib/mcp/client/mcp_param_headers.rb b/lib/mcp/client/mcp_param_headers.rb deleted file mode 100644 index 4aa4d54..0000000 --- a/lib/mcp/client/mcp_param_headers.rb +++ /dev/null @@ -1,242 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - # The custom-header half of SEP-2243 (MCP 2026-07-28): scanning a tool's `inputSchema` for - # `x-mcp-header` declarations and encoding `tools/call` argument values into `Mcp-Param-{Name}` HTTP headers, - # with the `=?base64?...?=` sentinel for values that cannot ride as plain ASCII field values. - # Mirrors the TypeScript SDK's `mcpParamHeaders` codec; the standard-header half (`Mcp-Method`, `Mcp-Name`) - # lives with the transport. - # - # https://modelcontextprotocol.io/specification/draft/basic/transports/streamable-http#custom-headers-from-tool-parameters - module McpParamHeaders - # The fixed prefix every custom-parameter header carries. - HEADER_PREFIX = "Mcp-Param-" - - # The schema-extension property name a tool's `inputSchema` carries. - X_MCP_HEADER_KEY = "x-mcp-header" - - # RFC 9110 Section 5.1 `token` syntax (`1*tchar`): rejects empty names, spaces, - # control characters (including CR/LF), and the HTTP delimiters. - RFC9110_TOKEN = /\A[!#$%&'*+\-.^_`|~0-9A-Za-z]+\z/.freeze - - # The spec text admits `string`, `integer`, and `boolean`. `number` is also accepted because - # the published conformance referee annotates `type: "number"` parameters and expects them - # mirrored; the TypeScript SDK makes the same accommodation. - PERMITTED_TYPES = ["string", "integer", "boolean", "number"].freeze - - # JSON Schema keywords the SEP-2243 static-reachability constraint excludes from - # the `properties`-only chain. An `x-mcp-header` under any of these invalidates - # the tool definition rather than being silently ignored. - NON_REACHABLE_SUBSCHEMA_KEYWORDS = [ - "items", - "prefixItems", - "contains", - "additionalProperties", - "unevaluatedProperties", - "unevaluatedItems", - "propertyNames", - "patternProperties", - "dependentSchemas", - "oneOf", - "anyOf", - "allOf", - "not", - "if", - "then", - "else", - "$defs", - "definitions", - ].freeze - - # Keywords whose value maps names to subschemas rather than being one subschema or a list of them. - OBJECT_VALUED_SUBSCHEMA_KEYWORDS = ["patternProperties", "dependentSchemas", "$defs", "definitions"].freeze - - # Integers beyond 2**53 - 1 lose precision in JSON number interchange, so they are not mirrored; - # the TypeScript SDK refuses unsafe integers the same way. - MAX_SAFE_INTEGER = (2**53) - 1 - - BASE64_SENTINEL_PREFIX = "=?base64?" - BASE64_SENTINEL_SUFFIX = "?=" - - class << self - # Scans a tool's `inputSchema` for `x-mcp-header` declarations and validates every constraint - # the spec places on them: RFC 9110 token names, case-insensitive uniqueness, primitive-typed - # declaring properties, and static reachability through a chain of `properties` keys only. - # Returns `{ valid: true, declarations: [...] }` with each declaration `{ path:, header_name:, type: }`, - # or `{ valid: false, reason: "..." }` on the first violation. - def scan(input_schema) - declarations = [] - fault = visit(input_schema, [], true, declarations, {}) - - fault ? { valid: false, reason: fault } : { valid: true, declarations: declarations } - end - - # Builds the `Mcp-Param-{Name}` headers for one `tools/call` from the scanned declarations and - # the call's `arguments`. A `null` or absent value omits its header (the spec's MUST-omit rows); - # a non-primitive or non-representable value is omitted rather than emitted malformed. - def build(declarations, arguments) - declarations.each_with_object({}) do |declaration, headers| - value = value_at_path(arguments, declaration[:path]) - next if value.nil? - - string_value = primitive_to_string(value) - next unless string_value - - encoded = begin - encode_value(string_value) - rescue EncodingError - # A string that cannot be represented as UTF-8 (e.g. binary data) has no header - # representation; omit it like the other non-representable values. - next - end - - headers["#{HEADER_PREFIX}#{declaration[:header_name]}"] = encoded - end - end - - # Converts a primitive argument to its header string per the spec's type-conversion rules: - # strings pass through, booleans become lowercase `"true"` / `"false"`, and numbers become - # their decimal string. `nil` means "not representable: do not emit a header". - def primitive_to_string(value) - case value - when String - value - when true - "true" - when false - "false" - when Integer - value.abs <= MAX_SAFE_INTEGER ? value.to_s : nil - when Float - return unless value.finite? - - # JSON has one number type: an integral float serializes without the fractional part, - # matching the `String(42.0)` the JavaScript reference emits. - value == value.truncate ? value.truncate.to_s : value.to_s - end - end - - # Encodes a header value per the spec's value-encoding rules: a safe plain-ASCII field value - # passes through unchanged, everything else is wrapped as `=?base64?{base64-of-UTF-8}?=`. - def encode_value(value) - return value unless needs_base64?(value) - - "#{BASE64_SENTINEL_PREFIX}#{[value.encode(Encoding::UTF_8)].pack("m0")}#{BASE64_SENTINEL_SUFFIX}" - end - - private - - def visit(node, path, reachable, declarations, seen_lower) - return unless node.is_a?(Hash) - - if key?(node, X_MCP_HEADER_KEY) - fault = validate_declaration(node, path, reachable, declarations, seen_lower) - - return fault if fault - end - - properties = read(node, "properties") - if properties.is_a?(Hash) - properties.each do |key, child| - fault = visit(child, path + [key.to_s], reachable, declarations, seen_lower) - - return fault if fault - end - end - - # Static-reachability sweep: descend the keywords the `properties` chain MUST NOT pass - # through with `reachable: false`, so an annotation under any of them is reported. - # `$defs` covers `$ref`-within-`$defs`; chasing arbitrary `$ref` URIs is out of scope. - NON_REACHABLE_SUBSCHEMA_KEYWORDS.each do |keyword| - next unless (sub = read(node, keyword)) - - branches = if sub.is_a?(Array) - sub - elsif sub.is_a?(Hash) && OBJECT_VALUED_SUBSCHEMA_KEYWORDS.include?(keyword) - sub.values - else - [sub] - end - - branches.each do |branch| - fault = visit(branch, path + ["<#{keyword}>"], false, declarations, seen_lower) - - return fault if fault - end - end - - nil - end - - def validate_declaration(node, path, reachable, declarations, seen_lower) - if !reachable || path.empty? - return "#{path_name(path)}: x-mcp-header is only permitted on properties statically reachable via a chain of `properties` keys" - - end - - annotation = read(node, X_MCP_HEADER_KEY) - - unless annotation.is_a?(String) && !annotation.empty? - return "#{path_name(path)}: x-mcp-header MUST be a non-empty string" - end - - unless RFC9110_TOKEN.match?(annotation) - return "#{path_name(path)}: x-mcp-header `#{annotation}` is not a valid RFC 9110 token" - end - - type = read(node, "type") - unless type.is_a?(String) && PERMITTED_TYPES.include?(type) - return "#{path_name(path)}: x-mcp-header is only permitted on primitive-typed properties " \ - "(got `#{type.inspect}`)" - end - - lower = annotation.downcase - prior = seen_lower[lower] - if prior - return "x-mcp-header `#{annotation}` is not case-insensitively unique (also declared as `#{prior}`)" - end - - seen_lower[lower] = annotation - declarations << { path: path, header_name: annotation, type: type } - nil - end - - # A value cannot ride as a plain ASCII field value when it is empty, already shaped like - # the Base64 sentinel (the spec's ambiguity rule), carries edge whitespace that field parsing - # would strip, or contains a byte outside visible ASCII plus interior tab. - def needs_base64?(value) - return true if value.empty? - return true if value.start_with?(BASE64_SENTINEL_PREFIX) && value.end_with?(BASE64_SENTINEL_SUFFIX) - return true if value != value.strip - - value.each_byte.any? { |byte| byte != 0x09 && !byte.between?(0x20, 0x7e) } - end - - def value_at_path(root, path) - path.reduce(root) do |node, key| - break unless node.is_a?(Hash) - - read(node, key) - end - end - - # Schemas and arguments arrive with string keys off the wire but may carry symbol keys - # when constructed in Ruby; read both forms like the SDK's other readers. - def read(hash, key) - value = hash[key] - - value.nil? ? hash[key.to_sym] : value - end - - def key?(hash, key) - hash.key?(key) || hash.key?(key.to_sym) - end - - def path_name(path) - path.empty? ? "" : path.join(".") - end - end - end - end -end diff --git a/lib/mcp/client/modern_envelope.rb b/lib/mcp/client/modern_envelope.rb deleted file mode 100644 index b9aed32..0000000 --- a/lib/mcp/client/modern_envelope.rb +++ /dev/null @@ -1,32 +0,0 @@ -# frozen_string_literal: true - -require_relative "../request_envelope" - -module MCP - class Client - # Stamps the SEP-2575 per-request `_meta` envelope onto outgoing modern requests. - # The reserved key names are shared with the server-side `MCP::RequestEnvelope`. - # Reserved keys always win over caller-supplied `_meta` entries because they are - # wire vocabulary the SDK is responsible for; every other entry is preserved. - module ModernEnvelope - extend self - - # Returns a copy of `request` with `params._meta` carrying the modern triple. - # Neither `request` nor its nested hashes are mutated. - def stamp(request, protocol_version:, client_info:, capabilities:) - params_key = request.key?("params") ? "params" : :params - params = request[params_key] || {} - meta_key = params.key?("_meta") ? "_meta" : :_meta - meta = params[meta_key] || {} - - stamped_meta = meta.merge( - RequestEnvelope::PROTOCOL_VERSION_META_KEY.to_sym => protocol_version, - RequestEnvelope::CLIENT_INFO_META_KEY.to_sym => client_info, - RequestEnvelope::CLIENT_CAPABILITIES_META_KEY.to_sym => capabilities, - ) - - request.merge(params_key => params.merge(meta_key => stamped_meta)) - end - end - end -end diff --git a/lib/mcp/client/oauth.rb b/lib/mcp/client/oauth.rb deleted file mode 100644 index ecacc88..0000000 --- a/lib/mcp/client/oauth.rb +++ /dev/null @@ -1,26 +0,0 @@ -# frozen_string_literal: true - -require_relative "oauth/authorization_request" -require_relative "oauth/bounded_body" -require_relative "oauth/discovery" -require_relative "oauth/flow" -require_relative "oauth/in_memory_storage" -require_relative "oauth/pkce" -require_relative "oauth/storage_backed_provider" -require_relative "oauth/jwt_client_assertion" -require_relative "oauth/provider" -require_relative "oauth/client_credentials_provider" -require_relative "oauth/id_jag_token_exchange" -require_relative "oauth/cross_app_access_provider" - -module MCP - class Client - # OAuth client support for the MCP Authorization spec (PRM discovery, - # Authorization Server metadata discovery, Dynamic Client Registration, - # OAuth 2.1 Authorization Code + PKCE, the client_credentials grant, - # and the SEP-990 Enterprise Managed Authorization jwt-bearer grant). - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization - module OAuth - end - end -end diff --git a/lib/mcp/client/oauth/authorization_request.rb b/lib/mcp/client/oauth/authorization_request.rb deleted file mode 100644 index 57462f5..0000000 --- a/lib/mcp/client/oauth/authorization_request.rb +++ /dev/null @@ -1,27 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # The decision an `authorization_request_validator` is asked to approve: which authorization server this client is about to send the user to, - # and with which scopes. - # - # Handed over as one object rather than as keyword arguments so that later revisions of the MCP authorization specification can add to it - # without changing the shape every implementer wrote. - # - # Only the named readers are the contract. The positional access `Struct` also provides (`request[0]`, `to_a`, `each`) is not, - # so the representation can change later. - AuthorizationRequest = Struct.new( - # `issuer` of the authorization server selected from the MCP server's Protected Resource Metadata. - :authorization_server, - # The scopes about to be requested, as an Array. Chosen by the MCP server, through the `WWW-Authenticate` challenge or `scopes_supported`. - :scopes, - # The MCP server URL this client was configured with. - :server_url, - # The RFC 8707 `resource` the token is being requested for. - :resource, - keyword_init: true, - ) - end - end -end diff --git a/lib/mcp/client/oauth/bounded_body.rb b/lib/mcp/client/oauth/bounded_body.rb deleted file mode 100644 index f3b5efa..0000000 --- a/lib/mcp/client/oauth/bounded_body.rb +++ /dev/null @@ -1,67 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # Bounds an OAuth response body while it arrives, rather than after it has been buffered. - # Discovery documents, registration responses, and token responses are all small by definition, - # so a body that keeps growing is never something worth holding in memory. Matches the 4 MiB cap of - # `MCP::Client::HTTP::MAX_MESSAGE_BYTES` and `MCP::Client::Stdio::MAX_LINE_BYTES`. - class BoundedBody - MAX_RESPONSE_BYTES = 4 * 1024 * 1024 - - # Raised while the body is read. Each caller translates it into its own error type, - # so this never reaches an embedder. - class TooLargeError < StandardError; end - - # What the OAuth code reads from a response. The Faraday response itself is not passed on, - # so a later caller cannot reach the unbounded `response.body` by accident. - Response = Struct.new(:status, :body) - - def initialize(max_bytes: MAX_RESPONSE_BYTES) - @max_bytes = max_bytes - @buffer = +"" - end - - # Faraday `on_data` streaming callback. The chunks arrive decompressed: the default `Net::HTTP` adapter negotiates - # `Accept-Encoding` itself and reads the body through `Net::HTTPResponse#inflater`, so a small compressed body - # that expands past the cap is refused partway through the expansion rather than after it. That holds only while - # the connection leaves `Accept-Encoding` to the adapter; see `Flow.build_http_client`. - def on_data - proc do |chunk, _received_bytes, _env| - @buffer << chunk - - raise TooLargeError, too_large_message if @buffer.bytesize > @max_bytes - end - end - - # The status paired with the bounded body. Adapters that ignore `on_data` leave the buffer empty and deliver - # the whole body in `response.body`, so that path is measured here instead; the bytes are already allocated by then, - # but refusing them still keeps an over-cap document out of `JSON.parse`. - def response_for(response) - Response.new(response.status, bounded_body(response)) - end - - private - - def bounded_body(response) - return @buffer unless @buffer.empty? - - body = response.body - body = body.is_a?(String) ? body : body.to_s - raise TooLargeError, too_large_message if body.bytesize > @max_bytes - - body - end - - def too_large_message - # Not "the authorization server": protected resource metadata comes from the MCP server's own origin, - # so this message covers endpoints on both sides of the flow. - "Response body from the OAuth endpoint exceeds #{@max_bytes} bytes" - end - end - - private_constant :BoundedBody - end - end -end diff --git a/lib/mcp/client/oauth/client_credentials_provider.rb b/lib/mcp/client/oauth/client_credentials_provider.rb deleted file mode 100644 index 4e1e1cf..0000000 --- a/lib/mcp/client/oauth/client_credentials_provider.rb +++ /dev/null @@ -1,161 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # OAuth client configuration for the OAuth 2.1 `client_credentials` grant - # (machine-to-machine, no user and no browser redirect). Handed to - # `MCP::Client::HTTP` via the `oauth:` keyword, the same as `Provider`. - # The interactive Authorization Code flow lives in `Provider`; - # this class exists so a credentials-only client never has to supply - # the redirect arguments that grant has no use for, mirroring the dedicated - # `ClientCredentialsProvider` in the TypeScript SDK and - # `ClientCredentialsOAuthProvider` in the Python SDK. - # - # Required keyword arguments: - # - # - `client_id` - String identifying the pre-registered confidential client. - # - `client_secret` - String shared secret for the `client_secret_basic` / - # `client_secret_post` methods. The `client_credentials` grant is for - # confidential clients, so a credential is mandatory; with - # `private_key_jwt` the credential is the `private_key` instead. - # - # Optional keyword arguments: - # - # - `token_endpoint_auth_method` - `"client_secret_basic"` (default), - # `"client_secret_post"`, or `"private_key_jwt"` (RFC 7523 JWT client - # assertion, per the `io.modelcontextprotocol/oauth-client-credentials` - # extension / SEP-1046). `"none"` is rejected: an unauthenticated - # `client_credentials` request is meaningless. - # - `private_key` - PEM string (or `OpenSSL::PKey::PKey`) used to sign - # the JWT client assertion. Required with `private_key_jwt`. - # The key is held on the provider and never written to `storage`. - # - `signing_algorithm` - `"ES256"` or `"RS256"`. Required with - # `private_key_jwt`; there is no default, so a mismatch with - # the server's `token_endpoint_auth_signing_alg_values_supported` fails - # loudly at construction instead of as a 401 (the TypeScript and Python SDKs - # also take the algorithm as an explicit option). - # - `scope` - String of space-separated scopes to request when the server's - # `WWW-Authenticate` and the Protected Resource Metadata do not specify one. - # - `storage` - Object responding to `tokens`, `save_tokens(tokens)`, `client_information`, - # and `save_client_information(info)`. Defaults to an `InMemoryStorage`. - # The `client_id` / `client_secret` are written into it so the token exchange reads - # them through the same path as a pre-registered authorization-code client. - # - `token_request_params` - Hash of String keys and values added to every - # token request this provider makes, for parameters the authorization - # server requires beyond the grant itself (Auth0's `audience`, for example). - # A key in `Flow::RESERVED_TOKEN_REQUEST_PARAMS` raises `Flow::InvalidTokenRequestParamsError`. - # The Hash is copied and frozen. See `StorageBackedProvider#token_request_params`. - # - `http_client_customizer` - Callable invoked with the `Faraday::Connection` the flow builds for - # its own requests; see `StorageBackedProvider#http_client_customizer`. - class ClientCredentialsProvider - include StorageBackedProvider - - # Raised when the credentials required for the `client_credentials` grant are - # missing or the requested client authentication method cannot carry them. - class InvalidCredentialsError < ArgumentError; end - - SUPPORTED_AUTH_METHODS = ["client_secret_basic", "client_secret_post", "private_key_jwt"].freeze - - attr_reader :scope, :storage - - def initialize( - client_id:, - client_secret: nil, - token_endpoint_auth_method: "client_secret_basic", - private_key: nil, - signing_algorithm: nil, - scope: nil, - storage: nil, - authorization_request_validator: nil, - token_request_params: nil, - http_client_customizer: nil - ) - if blank?(client_id) - raise InvalidCredentialsError, "client_id is required for the client_credentials grant." - end - - unless SUPPORTED_AUTH_METHODS.include?(token_endpoint_auth_method) - raise InvalidCredentialsError, - "token_endpoint_auth_method must be one of #{SUPPORTED_AUTH_METHODS.inspect} for the " \ - "client_credentials grant (got #{token_endpoint_auth_method.inspect}); an unauthenticated " \ - "client_credentials request is not allowed." - end - - client_information = { "client_id" => client_id, "token_endpoint_auth_method" => token_endpoint_auth_method } - - if token_endpoint_auth_method == "private_key_jwt" - validate_private_key_jwt_arguments!( - client_secret: client_secret, - private_key: private_key, - signing_algorithm: signing_algorithm, - ) - - # Fail fast on an unparseable key or a key/algorithm mismatch by - # signing a throwaway assertion now rather than at token time. - JWTClientAssertion.generate( - client_id: client_id, - audience: "urn:mcp:credential-validation", - private_key: private_key, - signing_algorithm: signing_algorithm, - ) - else - if blank?(client_secret) - raise InvalidCredentialsError, "client_secret is required for the client_credentials grant with #{token_endpoint_auth_method}." - end - - client_information["client_secret"] = client_secret - end - - http_client_customizer = validated_http_client_customizer(http_client_customizer) - - @client_id = client_id - @private_key = private_key - @signing_algorithm = signing_algorithm - @scope = scope - @storage = storage || InMemoryStorage.new - @authorization_request_validator = authorization_request_validator - @token_request_params = frozen_token_request_params(token_request_params) - @http_client_customizer = http_client_customizer - @storage.save_client_information(client_information) - end - - # See `Provider#authorization_flow`. - def authorization_flow - :client_credentials - end - - # Returns a freshly signed RFC 7523 JWT client assertion for the `private_key_jwt` method. - # `audience` is the authorization server's issuer identifier. Called by `Flow#post_to_token_endpoint`. - def client_assertion(audience:) - JWTClientAssertion.generate( - client_id: @client_id, - audience: audience, - private_key: @private_key, - signing_algorithm: @signing_algorithm, - ) - end - - private - - def validate_private_key_jwt_arguments!(client_secret:, private_key:, signing_algorithm:) - unless client_secret.nil? - raise InvalidCredentialsError, "client_secret must not be set with private_key_jwt; the private key is the credential." - end - - if private_key.nil? - raise InvalidCredentialsError, "private_key is required for the client_credentials grant with private_key_jwt." - end - - return unless blank?(signing_algorithm) - - raise InvalidCredentialsError, "signing_algorithm is required with private_key_jwt (one of #{JWTClientAssertion::SUPPORTED_ALGORITHMS.inspect})." - end - - def blank?(value) - value.nil? || (value.is_a?(String) && value.strip.empty?) - end - end - end - end -end diff --git a/lib/mcp/client/oauth/cross_app_access_provider.rb b/lib/mcp/client/oauth/cross_app_access_provider.rb deleted file mode 100644 index 44b5ffd..0000000 --- a/lib/mcp/client/oauth/cross_app_access_provider.rb +++ /dev/null @@ -1,100 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # OAuth client configuration for the MCP Enterprise Managed Authorization extension (SEP-990, "Cross-App Access"): - # the client obtains an Identity Assertion Authorization Grant (ID-JAG) from an enterprise identity provider and - # presents it to the MCP authorization server with the RFC 7523 `jwt-bearer` grant, authenticating with - # `client_secret_basic`. Handed to `MCP::Client::HTTP` via the `oauth:` keyword, the same as `Provider`. - # - # Mirrors `CrossAppAccessProvider` in the TypeScript SDK: the assertion is supplied by a callable so it can come - # from `IDJAGTokenExchange` (the common case), an enterprise secret store, or a test double. - # - # Required keyword arguments: - # - # - `client_id` - String identifying the pre-registered confidential client at the MCP authorization server. - # - `client_secret` - String shared secret for `client_secret_basic`. - # - `assertion_provider` - Callable invoked as `call(audience:, resource:)`, returning the ID-JAG assertion to - # present. `audience` is the authorization server's issuer identifier and `resource` is the canonical MCP server URL; - # pass both through to `IDJAGTokenExchange.request` when exchanging an IdP ID token. - # - # Optional keyword arguments: - # - # - `scope` - String of space-separated scopes to request when the server's `WWW-Authenticate` and - # the Protected Resource Metadata do not specify one. - # - `storage` - Object responding to `tokens`, `save_tokens(tokens)`, `client_information`, and `save_client_information(info)`. - # Defaults to an `InMemoryStorage`. - # - `token_request_params` - Hash of String keys and values added to the `jwt-bearer` token request, for parameters - # the authorization server requires beyond the grant itself. A key in `Flow::RESERVED_TOKEN_REQUEST_PARAMS` raises - # `Flow::InvalidTokenRequestParamsError`. The Hash is copied and frozen. - # See `StorageBackedProvider#token_request_params`. - # - `http_client_customizer` - Callable invoked with the `Faraday::Connection` the flow builds for its own requests; - # see `StorageBackedProvider#http_client_customizer`. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/issues/990 - class CrossAppAccessProvider - include StorageBackedProvider - - # Raised when the provider is constructed without the pieces the `jwt-bearer` grant needs. - class InvalidConfigurationError < ArgumentError; end - - attr_reader :scope, :storage - - def initialize( - client_id:, - client_secret:, - assertion_provider:, - scope: nil, - storage: nil, - authorization_request_validator: nil, - token_request_params: nil, - http_client_customizer: nil - ) - if blank?(client_id) - raise InvalidConfigurationError, "client_id is required for the jwt-bearer grant." - end - - if blank?(client_secret) - raise InvalidConfigurationError, "client_secret is required: SEP-990 authenticates the jwt-bearer grant with client_secret_basic." - end - - unless assertion_provider.respond_to?(:call) - raise InvalidConfigurationError, "assertion_provider must be callable as `call(audience:, resource:)` and return the ID-JAG assertion." - end - - http_client_customizer = validated_http_client_customizer(http_client_customizer) - - @assertion_provider = assertion_provider - @scope = scope - @storage = storage || InMemoryStorage.new - @authorization_request_validator = authorization_request_validator - @token_request_params = frozen_token_request_params(token_request_params) - @http_client_customizer = http_client_customizer - @storage.save_client_information( - "client_id" => client_id, - "client_secret" => client_secret, - "token_endpoint_auth_method" => "client_secret_basic", - ) - end - - # See `Provider#authorization_flow`. - def authorization_flow - :jwt_bearer - end - - # Returns the ID-JAG assertion to present at the MCP authorization server. Called by `Flow#run_jwt_bearer!` with the audience - # and resource resolved during discovery. - def jwt_bearer_assertion(audience:, resource:) - @assertion_provider.call(audience: audience, resource: resource) - end - - private - - def blank?(value) - value.nil? || (value.is_a?(String) && value.strip.empty?) - end - end - end - end -end diff --git a/lib/mcp/client/oauth/discovery.rb b/lib/mcp/client/oauth/discovery.rb deleted file mode 100644 index a8ad3be..0000000 --- a/lib/mcp/client/oauth/discovery.rb +++ /dev/null @@ -1,625 +0,0 @@ -# frozen_string_literal: true - -require "ipaddr" -require "uri" - -module MCP - class Client - module OAuth - # Stateless helpers that map MCP-authorization spec URLs and headers into something - # the `Flow` orchestrator and `MCP::Client::HTTP` transport can act on. - # The module bundles six concerns that share no state but are closely related to - # the spec's "Discovery" and "Communication Security" sections: - # - # - **`WWW-Authenticate` parsing** (`parse_www_authenticate`): pulls - # the Bearer challenge parameters (`resource_metadata`, `scope`, `error`, - # ...) out of a header that may carry multiple challenges per RFC 7235 - # and may use `quoted-pair` escapes per RFC 7230 Section 3.2.6. - # - **Discovery URL builders** (`protected_resource_metadata_urls`, - # `authorization_server_metadata_urls`): list the candidate well-known - # URLs to probe when no explicit metadata URL is supplied, - # in the priority order required by RFC 9728 and RFC 8414. - # - **Communication Security check** (`secure_url?`): enforces "HTTPS only" - # for every OAuth-facing URL, with the loopback carve-out described in - # `secure_url?`'s comment. - # - **Destination checks** (`same_origin?`, `private_network_host?`): - # answer *where* a URL points, which the scheme alone does not. `Flow` uses - # them to refuse server-supplied discovery URLs aimed at hosts the MCP server - # has no business steering the client toward. - # - **URL canonicalization** (`canonicalize_url`): normalizes scheme, - # host, port, path, percent-encoded dot segments, and fragments - # so two URLs that *refer to the same resource* compare as equal, - # and drops userinfo so credentials never reach the RFC 8707 `resource` claim - # or any error message. - # - **Resource coverage** (`resource_covers?`): decides whether a PRM `resource` URI - # is allowed to govern a given MCP server URL, i.e. whether the MCP endpoint sits - # "under" the resource per RFC 8707 audience semantics. - # - # Every entry point is a class method so it can be called from initializers and - # from any thread without synchronization. - module Discovery - # Matches a single `key=value` pair inside an HTTP auth-scheme challenge. - # `value` is either a quoted string (which can contain commas and spaces) - # or a bare token, per RFC 7235. - WWW_AUTH_PARAM_PATTERN = /\A([A-Za-z0-9_-]+)\s*=\s*(?:"((?:[^"\\]|\\.)*)"|([^\s,]+))/.freeze - - class << self - # Parses a `WWW-Authenticate` header and returns the parameters of - # the `Bearer` challenge as a hash with lower-cased keys (e.g. `resource_metadata`, - # `scope`, `error`). Returns `{}` when no Bearer challenge is present. - # Handles multiple challenges (e.g. `Basic ..., Bearer ...` or `Bearer ..., DPoP ...`) - # by extracting only the Bearer parameters. - # - # - https://www.rfc-editor.org/rfc/rfc9728.html#section-5.1 - # - https://www.rfc-editor.org/rfc/rfc7235.html#section-4.1 - def parse_www_authenticate(header) - return {} unless header - - # Locate the Bearer challenge: at the start of the header or after a comma. - bearer = header.match(/(?:\A|,)\s*Bearer(?:\s+|\z)/i) - return {} unless bearer - - # Walk key=value pairs starting where Bearer's parameters begin. - # The loop stops at the first token that is not a key=value pair, - # which marks the next challenge (e.g. `, DPoP algs="..."`). - cursor = bearer.end(0) - params = {} - while cursor < header.length - prefix = header[cursor..] - prefix = prefix.sub(/\A\s*,?\s*/, "") - break if prefix.empty? - - match = prefix.match(WWW_AUTH_PARAM_PATTERN) - break unless match - - params[match[1].downcase] = match[2] ? unescape_quoted_pair(match[2]) : match[3] - cursor = header.length - prefix.length + match.end(0) - end - params - end - - # Returns the candidate Protected Resource Metadata URLs to probe, in priority order. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#protected-resource-metadata-discovery-requirements - def protected_resource_metadata_urls(server_url:, resource_metadata_url: nil) - urls = [] - urls << resource_metadata_url if resource_metadata_url - - uri = URI.parse(server_url) - path = uri.path == "/" ? "" : uri.path.to_s - base = base_url(uri) - - urls << "#{base}/.well-known/oauth-protected-resource#{path}" - urls << "#{base}/.well-known/oauth-protected-resource" - urls.uniq - end - - # Returns the candidate Authorization Server metadata URLs to probe, in priority order. - # - # Per SEP-2351, MCP uses the default `oauth-authorization-server` well-known URI suffix - # registered by RFC 8414 Section 7.3 and defines no application-specific suffix of its own. - # The OAuth candidates below therefore use only that default suffix - # (plus the `openid-configuration` suffix from OpenID Connect Discovery), - # both in the RFC 8414 Section 3.1 path-inserted form for issuers with a path component - # and in the root form for issuers without one. - # - # - https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#authorization-server-metadata-discovery - # - https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2351 - # - https://www.rfc-editor.org/rfc/rfc8414#section-3.1 - def authorization_server_metadata_urls(issuer_url) - uri = URI.parse(issuer_url) - path = uri.path == "/" ? "" : uri.path.to_s - base = base_url(uri) - - if path.empty? - ["#{base}/.well-known/oauth-authorization-server", "#{base}/.well-known/openid-configuration"] - else - [ - "#{base}/.well-known/oauth-authorization-server#{path}", - "#{base}/.well-known/openid-configuration#{path}", - "#{base}#{path}/.well-known/openid-configuration", - ] - end - end - - # Returns a canonical form of `url` suitable for comparing two URIs - # that are meant to identify the same protected resource: lowercased scheme/host, - # default port stripped, fragment removed, percent-encoded dot octets normalized - # to `.` per RFC 3986 Section 6.2.2.2, dot-segments in the path resolved per - # RFC 3986 Section 5.2.4, and a single trailing `/` on the root path normalized away. - # - # Userinfo is *dropped*. The MCP authorization spec sends the canonicalized URL - # on the wire as the RFC 8707 `resource` claim and surfaces it in error messages; - # both paths would leak `user:pass@` credentials to the authorization server and - # to log destinations if we preserved them. The MCP server URI does not legitimately - # carry userinfo, so dropping it is also a no-op for normal traffic. - # - # Decoding `%2e`/`%2E` *before* dot-segment resolution is what prevents - # an attacker-supplied URL like `https://srv.example.com/api/%2e%2e/mcp` from sneaking - # past the PRM `resource` check in `resource_covers?`. - def canonicalize_url(url) - uri = URI.parse(url.to_s) - - uri.fragment = nil - # `URI::Generic#userinfo=` is a no-op on Ruby 2.7 (the project's minimum supported version), - # so clear the components individually. - if uri.respond_to?(:user) && (uri.user || uri.password) - uri.user = nil - uri.password = nil - end - uri.scheme = uri.scheme.downcase if uri.scheme - uri.host = uri.host.downcase if uri.host - uri.port = nil if uri.port == uri.default_port - - path = uri.path.to_s.gsub(/%2[eE]/, ".") - uri.path = remove_dot_segments(path) - uri.path = "" if uri.path == "/" - - uri.query = normalize_query(uri.query) - - uri.to_s - end - - # Returns true when `url` is safe to use for OAuth communication per - # the MCP authorization spec's "Communication Security" requirement: - # `https` is always allowed, `http` is permitted only when the host is - # a loopback address (`localhost`, `127.0.0.0/8`, or `::1`). - # - # The loopback exception applies uniformly to every OAuth-related URL - # the SDK consumes (PRM URL, AS metadata URL, `authorization_servers` - # entries, `authorization_endpoint`, `token_endpoint`, `registration_endpoint`, - # the `redirect_uri`, and the MCP transport URL when `oauth:` is set). - # A strict reading of OAuth 2.1 reserves the loopback carve-out for - # `redirect_uri` only (per RFC 8252), but neither the Python nor - # the TypeScript MCP SDK enforces HTTPS on those endpoints either - - # and the official MCP conformance test suite drives its fixtures - # over `http://localhost` auth servers, so enforcing HTTPS for everything - # except `redirect_uri` would break local development out of the box and - # regress 16 conformance scenarios. Operators who run in production are - # expected to deploy real HTTPS endpoints; this helper does not enforce - # that at the SDK boundary. - # - # Rejects URLs that fail to parse, lack a host, or whose `http://` host is - # something like `127.attacker.com` or `foo.localhost`, - # which would otherwise pass a naive `start_with?("127.")` check. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#communication-security - def secure_url?(url) - return false if url.nil? || url.to_s.empty? - - uri = URI.parse(url.to_s) - return false if uri.host.nil? || uri.host.empty? - - scheme = uri.scheme&.downcase - return true if scheme == "https" - return loopback_host?(uri.host) if scheme == "http" - - false - rescue URI::InvalidURIError - false - end - - # Returns true when `url` and `other` share an origin: same scheme, same host, - # and same port. Scheme and host compare case-insensitively, and an implicit default port compares - # equal to the same port written out, because `URI::HTTP#port` already resolves to the default. - # - # Anything that fails to parse or carries no host returns false, so a caller using this as - # a security gate refuses rather than admits on malformed input. - def same_origin?(url, other) - uri = URI.parse(url.to_s) - other_uri = URI.parse(other.to_s) - return false if uri.host.nil? || uri.host.empty? - return false if other_uri.host.nil? || other_uri.host.empty? - - uri.scheme&.downcase == other_uri.scheme&.downcase && - uri.host.downcase == other_uri.host.downcase && - uri.port == other_uri.port - rescue URI::InvalidURIError - false - end - - # Returns true when `host` is an IP literal that is not reachable from the public internet, - # or the `localhost` name. The ranges are the ones RFC 9728 Section 7.7 and the MCP security best practices name - # as SSRF targets, so `169.254.0.0/16` covers the `169.254.169.254` cloud metadata address that motivates the check. - # - # Hostnames are deliberately NOT resolved. A lookup here would be a second network request driven by - # the same untrusted input, and the address it returned could differ from the one the HTTP client connects to - # a moment later, so the check would read as a guarantee it cannot make. That leaves names like `vault.corp.internal` - # out of reach of this predicate; it is one layer of an SSRF defense, not the whole of one. - def private_network_host?(host) - return false if host.nil? || host.empty? - - normalized = host.downcase - return true if normalized == "localhost" - - literal = normalized.delete_prefix("[").delete_suffix("]") - address = parse_ip_address(literal) - return numeric_ipv4_spelling?(literal) unless address - - # `::ffff:169.254.169.254` addresses the same interface as `169.254.169.254`, - # so compare the IPv4 form rather than letting the mapped spelling through. - address = address.native if address.ipv6? && address.ipv4_mapped? - - ranges = address.ipv4? ? PRIVATE_IPV4_RANGES : PRIVATE_IPV6_RANGES - ranges.any? { |range| range.include?(address) } - end - - # Returns true when `url` satisfies the structural requirements for - # a Client ID Metadata Document URL per the MCP 2025-11-25 - # authorization specification and `draft-ietf-oauth-client-id-metadata-document-00`. - # - # Spec-required: - # - # - scheme MUST be `https` (the loopback-`http` carve-out used for discovery does not apply: - # the document URL is sent verbatim to the authorization server as the OAuth `client_id` - # and travels off-loopback) - # - host MUST be present - # - path MUST be non-empty and MUST NOT be the root (`/`); the document is a discrete resource, - # not the origin - # - URL MUST NOT carry a fragment or userinfo: a fragment is not sent to the server, and userinfo - # would leak credentials into every `client_id` log line - # - path MUST be already free of `.` / `..` dot segments after percent-decoding, so two URLs with - # the same effective path do not produce different `client_id` strings - # - # SDK policy (stricter than the draft): - # - # - URL MUST NOT carry a query string. The draft marks query components only SHOULD NOT include, - # but different encodings of the same query (`?a=1&b=2` vs `?b=2&a=1`) would yield distinct - # `client_id` values for the same logical document. - def client_id_metadata_document_url?(url) - return false if url.nil? || url.to_s.empty? - - uri = URI.parse(url.to_s) - return false unless uri.scheme&.downcase == "https" - return false if uri.host.nil? || uri.host.empty? - return false unless uri.fragment.nil? - return false unless uri.query.nil? - return false if uri.respond_to?(:user) && (uri.user || uri.password) - - path = uri.path.to_s - return false if path.empty? || path == "/" - - decoded = path.gsub(/%2[eE]/, ".") - segments = decoded.split("/", -1) - return false if segments.any? { |segment| segment == "." || segment == ".." } - - true - rescue URI::InvalidURIError - false - end - - # Infers the OIDC Dynamic Client Registration `application_type` for a client from its `redirect_uris`. - # Per SEP-837, MCP clients MUST specify an appropriate application type during Dynamic Client Registration - # so the authorization server can apply the matching redirect URI policy. - # - # Returns `"native"` when every redirect URI is a native-app URI: a custom non-http(s) scheme (RFC 8252 Section 7.1) - # or an http(s) URI whose host is a loopback address (`localhost`, `127.0.0.0/8`, or `::1`, RFC 8252 Section 7.3). - # Returns `"web"` otherwise, including when `redirect_uris` is nil, empty, or contains an unparseable URI. - # - # - https://github.com/modelcontextprotocol/modelcontextprotocol/pull/837 - # - https://openid.net/specs/openid-connect-registration-1_0.html#ClientMetadata - def infer_application_type(redirect_uris) - uris = Array(redirect_uris) - return "web" if uris.empty? - - uris.all? { |uri| native_redirect_uri?(uri) } ? "native" : "web" - end - - # Like `canonicalize_url` but also strips query string, fragment, and - # userinfo. This variant is used for identity comparison against - # the request URL Faraday actually sends, which differs from the value - # the caller passed in two ways: `Faraday::Connection#url_prefix` - # drops query parameters, and Faraday hoists `user:pass@` out of - # the URL into an `Authorization: Basic` header before the request goes - # out. Including userinfo here would (a) raise a false-positive - # `InsecureURLError` on any legitimate URL with credentials in - # the authority, and (b) leak `user:pass` through the resulting error - # message - both of which would defeat the bearer-token-protection - # purpose of the identity check. - def canonicalize_origin_and_path(url) - uri = URI.parse(url.to_s) - - uri.fragment = nil - uri.query = nil - # `URI::Generic#userinfo=` is a no-op on Ruby 2.7 (the project's minimum supported version), - # so clear the components individually. - if uri.respond_to?(:user) && (uri.user || uri.password) - uri.user = nil - uri.password = nil - end - uri.scheme = uri.scheme.downcase if uri.scheme - uri.host = uri.host.downcase if uri.host - uri.port = nil if uri.port == uri.default_port - - path = uri.path.to_s.gsub(/%2[eE]/, ".") - uri.path = remove_dot_segments(path) - uri.path = "" if uri.path == "/" - - uri.to_s - end - - # Drops userinfo, query and fragment from `url` and leaves the host and path spelled as given, for reporting - # a URL next to the request that failed, where it must still match the server's access log; `URI#to_s` - # still lowercases the scheme and drops an explicit default port. Unlike `canonicalize_origin_and_path` - # it neither normalizes nor resolves dot segments, so its cost stays linear in the URL length, which matters - # for a URL the server chose. A URL that does not parse is not echoed, since the raw value could carry - # the very credentials being dropped. - def redact_url(url) - uri = URI.parse(url.to_s) - - uri.fragment = nil - uri.query = nil - # `URI::Generic#userinfo=` is a no-op on Ruby 2.7 (the project's minimum supported version), - # so clear the components individually. - if uri.respond_to?(:user) && (uri.user || uri.password) - uri.user = nil - uri.password = nil - end - - uri.to_s - rescue URI::Error - "[unparseable URL]" - end - - # Returns true when `prm` (a PRM `resource` URL) covers `server` (the MCP endpoint URL): - # same scheme/host/port, with PRM's path being a prefix of the server's path. When PRM - # also advertises a query string, the server's query MUST be identical to it (otherwise - # a hijacked PRM that advertises `?tenant=evil` would cover an MCP server at `?tenant=victim` - # and let the attacker mint a different tenant's token for the same origin + path). - # PRM with *no* query (URI#query returns `nil`) acts as a generic identifier over - # the origin + path prefix and covers any server query. - # - # An empty query (`prm_url?` -- URI#query returns `""`) is NOT treated as wildcard: - # it represents the URI literally `<...>?`, which is distinct from "no query at all" - # and from any non-empty query, so it must match exactly. - # - # Both arguments must already be canonicalized. - def resource_covers?(prm:, server:) - prm_uri = URI.parse(prm) - server_uri = URI.parse(server) - return false unless prm_uri.scheme == server_uri.scheme && - prm_uri.host == server_uri.host && - prm_uri.port == server_uri.port - - prm_path = prm_uri.path.to_s - server_path = server_uri.path.to_s - prm_path = "" if prm_path == "/" - server_path = "" if server_path == "/" - path_covers = server_path == prm_path || server_path.start_with?("#{prm_path}/") - return false unless path_covers - - prm_query = prm_uri.query - return true if prm_query.nil? - - prm_query == server_uri.query - end - - private - - # Unescapes a `quoted-string` value's `quoted-pair` octets per - # RFC 7230 Section 3.2.6 (referenced from RFC 7235): `\` becomes ``. - # https://www.rfc-editor.org/rfc/rfc7230#section-3.2.6 - def unescape_quoted_pair(value) - value.gsub(/\\(.)/, '\1') - end - - # Recognizes the IPv4 loopback range (`127.0.0.0/8`), IPv6 loopback - # (`::1`, optionally bracketed by `URI.parse`), and the `localhost` - # hostname (matched exactly so that hostnames like `foo.localhost` or - # `127.attacker.com` are not treated as loopback). - IPV4_LOOPBACK_RANGE = IPAddr.new("127.0.0.0/8") - IPV6_LOOPBACK = IPAddr.new("::1") - private_constant :IPV4_LOOPBACK_RANGE, :IPV6_LOOPBACK - - # Backing ranges for `private_network_host?`. - # - # `0.0.0.0/8` is "this network" and `100.64.0.0/10` is the carrier-grade NAT - # space; neither is a destination a legitimate authorization server publishes, - # and both are reachable enough from a client's network position to be worth - # refusing. `::/96` covers the unspecified address, IPv6 loopback, and - # the deprecated IPv4-compatible form (`::10.0.0.1`) in one range. - PRIVATE_IPV4_RANGES = [ - IPAddr.new("0.0.0.0/8"), - IPAddr.new("10.0.0.0/8"), - IPAddr.new("100.64.0.0/10"), - IPAddr.new("127.0.0.0/8"), - IPAddr.new("169.254.0.0/16"), - IPAddr.new("172.16.0.0/12"), - IPAddr.new("192.168.0.0/16"), - ].freeze - PRIVATE_IPV6_RANGES = [ - IPAddr.new("::/96"), - IPAddr.new("fc00::/7"), - IPAddr.new("fe80::/10"), - ].freeze - private_constant :PRIVATE_IPV4_RANGES, :PRIVATE_IPV6_RANGES - - def loopback_host?(host) - return false if host.nil? || host.empty? - - normalized = host.downcase - return true if normalized == "localhost" - - ip_candidate = normalized.delete_prefix("[").delete_suffix("]") - address = parse_ip_address(ip_candidate) - return false unless address - - return IPV4_LOOPBACK_RANGE.include?(address) if address.ipv4? - return address == IPV6_LOOPBACK if address.ipv6? - - false - end - - def parse_ip_address(candidate) - IPAddr.new(candidate) - rescue IPAddr::Error - nil - end - - # Matches one part of the `inet_aton` numeric grammar: hexadecimal (`0x7f`), - # octal (`0177`), or decimal (`127`). - INET_ATON_PART = /\A(?:0x\h+|0[0-7]*|[1-9]\d*)\z/.freeze - private_constant :INET_ATON_PART - - # Returns true when `host` is written in the numeric IPv4 grammar `inet_aton` accepts - # and `IPAddr` rejects: one to four dot-separated parts, each hexadecimal, octal, or - # decimal, with the last part filling the remaining bytes. `2130706433`, `127.1`, and - # `0x7f000001` all reach 127.0.0.1, and `0xa9fea9fe` reaches the cloud metadata address, - # so a check that understood only the canonical form would refuse `169.254.169.254` - # while waving through every other spelling of it. - # - # Such a host is refused outright rather than decoded and range-checked, because its - # value is resolver-dependent: a leading zero reads as octal on one platform and decimal - # on another, which is the difference between 8.0.0.1 and 10.0.0.1 for `010.0.0.1`. - # Deciding here which one it meant would leave whichever reading was not taken as a way - # through. No authorization server is legitimately addressed in this notation, so - # refusing the grammar entirely costs nothing and leaves no spelling to miss. - def numeric_ipv4_spelling?(host) - parts = host.split(".", -1) - return false if parts.empty? || parts.length > 4 - - parts.all? { |part| INET_ATON_PART.match?(part) } - end - - # A redirect URI counts as native when it uses a custom non-http(s) scheme - # (e.g. `com.example.app:/callback`) or when it is an http(s) URI whose host is - # a loopback address. A URI without a scheme or one that fails to parse is not native. - def native_redirect_uri?(url) - uri = URI.parse(url.to_s) - scheme = uri.scheme&.downcase - return false if scheme.nil? - return loopback_host?(uri.host) if ["http", "https"].include?(scheme) - - true - rescue URI::InvalidURIError - false - end - - def base_url(uri) - port_part = uri.port && uri.port != uri.default_port ? ":#{uri.port}" : "" - "#{uri.scheme}://#{uri.host}#{port_part}" - end - - # Normalizes a URL query string so two URLs that are equivalent in - # OAuth identity terms compare as equal. This is required because - # Faraday transparently rewrites `env.url` before sending a request: - # - # - Parameters get sorted by name (`?b=2&a=1` -> `?a=1&b=2`). - # - Percent-encoded hex is uppercased (`?x=%2f` -> `?x=%2F`). - # - A trailing `?` with no parameters is dropped (`?` -> no query). - # - Same-name keys are collapsed so only the last value survives - # (`?a=1&a=2` -> `?a=2`). - # - Empty-name pairs and blank `&&` separators are dropped - # (`?=v` -> no query, `?&&a=1&&` -> `?a=1`). - # - Value-less keys (`?tenant`) and empty-value keys (`?tenant=`) - # are kept distinct -- Faraday preserves the `=` exactly as - # the caller passed it. `URI.decode_www_form` / `encode_www_form` - # would collapse both to `?tenant=`, so this function does - # the parsing by hand on `&`-separated segments. - # - # Without applying the same transformation to our snapshotted URL, - # the request-time URL guard would false-positive on every URL that - # falls under one of the rules above. - # - # Returns `nil` when the resulting query is empty - # (matching Faraday's drop-empty-query behavior). - def normalize_query(query) - return if query.nil? || query.empty? - - # Each segment becomes `[decoded_name, has_equals?, decoded_value_or_nil]`. - # `has_equals?` is what lets us preserve the `?key` vs `?key=` - # distinction that Faraday respects. - parsed = query.split("&").filter_map do |segment| - next if segment.empty? - - name_raw, separator, value_raw = segment.partition("=") - name = URI.decode_www_form_component(name_raw) - next if name.empty? - - has_equals = !separator.empty? - value = has_equals ? URI.decode_www_form_component(value_raw) : nil - [name, has_equals, value] - end - - # Keys ending in `[]` (`tenant[]`, `roles[]`) are Faraday's array - # notation: the encoder preserves every occurrence in input order - # instead of collapsing them. All other keys (`tenant`, `a[b]`, - # plain scalars) are collapsed with last-write-wins semantics. - # Separating the two avoids a false negative where a hijacked - # middleware drops an entry from a `?tenant[]=victim&tenant[]=...` - # URL and slips past the guard, and a false positive on - # a legitimate `?roles[]=a&roles[]=b` URL. - array_segments = [] - scalar_segments = {} - parsed.each do |name, has_equals, value| - if name.end_with?("[]") - array_segments << [name, has_equals, value] - else - scalar_segments[name] = [has_equals, value] - end - end - - scalar_entries = scalar_segments.map { |name, (has_equals, value)| [name, has_equals, value] } - combined = scalar_entries + array_segments - return if combined.empty? - - # Stable sort by name: array entries that share a name keep their - # original order, while scalar names are alphabetized to match - # Faraday's deterministic encoding order. - combined.each_with_index - .sort_by { |(name, _, _), index| [name, index] } - .map do |(name, has_equals, value), _index| - encoded_name = URI.encode_www_form_component(name) - if has_equals - "#{encoded_name}=#{URI.encode_www_form_component(value)}" - else - encoded_name - end - end.join("&") - end - - # Implements RFC 3986 Section 5.2.4 `remove_dot_segments`. Walks the input - # buffer one segment at a time, popping the previous output segment - # whenever a `..` is encountered, so that `/api/../mcp` collapses to - # `/mcp` and `/foo/./bar` collapses to `/foo/bar`. - # https://www.rfc-editor.org/rfc/rfc3986#section-5.2.4 - def remove_dot_segments(path) - return path if path.nil? || path.empty? - - input = path.dup - output = +"" - until input.empty? - if input.start_with?("../") - input = input[3..] - elsif input.start_with?("./") - input = input[2..] - elsif input.start_with?("/./") - input = "/#{input[3..]}" - elsif input == "/." - input = "/" - elsif input.start_with?("/../") - input = "/#{input[4..]}" - output = remove_last_segment(output) - elsif input == "/.." - input = "/" - output = remove_last_segment(output) - elsif input == "." || input == ".." - input = "" - else - segment = input.match(%r{\A/?[^/]*})[0] - output << segment - input = input[segment.length..] - end - end - output - end - - def remove_last_segment(output) - idx = output.rindex("/") - return +"" if idx.nil? - - output[0...idx] - end - end - end - end - end -end diff --git a/lib/mcp/client/oauth/flow.rb b/lib/mcp/client/oauth/flow.rb deleted file mode 100644 index 58c234d..0000000 --- a/lib/mcp/client/oauth/flow.rb +++ /dev/null @@ -1,1457 +0,0 @@ -# frozen_string_literal: true - -require "base64" -require "json" -require "openssl" -require "securerandom" -require "uri" - -module MCP - class Client - module OAuth - # Internal orchestrator for the MCP OAuth 2.1 + PKCE + DCR authorization flow. - # Driven by `MCP::Client::HTTP` on a 401 response. The user-facing surface is - # `Provider`; this class consumes a Provider plus signal data extracted from - # the failing response (resource_metadata URL, scope challenge). - class Flow - TOKEN_ENDPOINT_ERROR_MAX_LENGTH = 128 - TOKEN_ENDPOINT_ERROR_DESCRIPTION_MAX_LENGTH = 512 - METADATA_DIAGNOSTIC_MAX_LENGTH = 128 - METADATA_URL_MAX_LENGTH = 2048 - - # Token request parameters the flow sets itself. Its values win over a provider's `token_request_params`, - # so a provider naming one of these is refused rather than left believing its value was sent. - RESERVED_TOKEN_REQUEST_PARAMS = [ - "grant_type", - "client_id", - "client_secret", - "client_assertion", - "client_assertion_type", - "scope", - "resource", - "code", - "code_verifier", - "redirect_uri", - "refresh_token", - "assertion", - ].freeze - - class AuthorizationError < StandardError - attr_reader :http_status, :error, :error_description - - def initialize(message = nil, http_status: nil, error: nil, error_description: nil) - super(message) - @http_status = http_status - @error = error - @error_description = error_description - end - end - - # Raised specifically when the token endpoint rejects a grant with - # `error: "invalid_grant"` (RFC 6749 §5.2). Callers use this to - # distinguish "the stored refresh token is dead, discard it" from - # transient failures (network, 5xx, other RFC 6749 error codes) that - # should leave the refresh token intact. - class InvalidGrantError < AuthorizationError; end - - # Raised when `authorization_request_validator` returns a falsy value. Separate from its parent - # so that a caller can tell a refusal by its own policy from a network, discovery, - # or authorization server metadata failure by rescuing a class rather than by matching the message text. - class AuthorizationRefusedError < AuthorizationError; end - - # Raised by metadata discovery when every candidate URL answered that nothing usable is published there - # (a `4xx` other than `429`, a redirect that was not followed, or a body that is not a JSON object). - # The only discovery failure that may select the legacy 2025-03-26 path. - class MetadataNotPublishedError < AuthorizationError; end - - # Raised by metadata discovery when the answer says nothing about what is published: the request failed to - # reach the server, or a candidate answered `5xx` or `429`. Falling back on this would move - # the flow to a different authorization server because of a transient failure, so it is surfaced instead, - # as the TypeScript SDK does for network errors outside browsers and the Python SDK does for both. - class MetadataUnreachableError < AuthorizationError; end - - # Raised for a `token_request_params` value the SDK refuses: a reserved key, a Hash comparing keys by identity, - # or anything but a Hash of Strings. An `ArgumentError` because the value is a configuration mistake, - # not a failed authorization, and deliberately outside `AuthorizationError`, which `MCP::Client::HTTP` treats on - # a failed refresh as a reason to run the interactive flow. - class InvalidTokenRequestParamsError < ArgumentError; end - - # Raised by `RequestedOriginGuard` when middleware added through the provider's `http_client_customizer` - # would send a request to an origin other than the one the flow validated, or has dropped the record of - # the URL the flow asked for. An `ArgumentError` because the middleware is a configuration mistake, - # and deliberately outside `AuthorizationError`, which discovery treats as "nothing published" - # and `MCP::Client::HTTP` treats on a failed refresh as a reason to run the interactive flow. - class DestinationMismatchError < ArgumentError; end - - # Faraday middleware registered on the connection `build_http_client` assembles before the customizer - # is invoked, so with the usual `use` it sits ahead of the customizer's middleware and sees the URL exactly - # as the flow requested it, which it records on the request environment for `RequestedOriginGuard`. - # The guard covers what happens to a request after that record; middleware inserted ahead of it with - # `builder.insert(0, ...)` that rewrites the URL before it or rebuilds the environment is outside the guard. - # The record lives on the environment, not in `env.request.context`: that slot belongs to the application, - # which may fill it on the connection or replace it from a middleware of its own. Only the first URL seen - # on an environment is recorded: a middleware inserted ahead of this one that re-enters the stack after - # a `3xx` with the same environment, or with its `dup`, which shares the record, cannot replace it with - # the redirected URL. - class RequestedURLStamp - KEY = :mcp_oauth_requested_url - - def initialize(app) - @app = app - end - - def call(env) - env[KEY] ||= env.url.to_s - @app.call(env) - end - end - - # Faraday middleware registered last on that connection, so it sees `env.url` after any customizer-added - # middleware has rewritten it or followed a redirect. A request that would leave the origin the flow asked - # for is refused before it reaches the adapter, since every destination check ran against the URL as - # written; a same-origin change stays with the server those checks admitted. The record survives - # the `env.dup` that redirect-following middleware performs, and a request that arrives without it is - # refused as well, so a middleware that rebuilds the environment fails closed rather than open. - # The origin boundary resembles the one the Python SDK keeps for its own auth requests, which follows - # a redirect itself only within the origin; this flow follows none. - class RequestedOriginGuard - def initialize(app) - @app = app - end - - def call(env) - requested = env[RequestedURLStamp::KEY] - unless requested - raise DestinationMismatchError, <<~MESSAGE - Request to #{Discovery.canonicalize_origin_and_path(env.url.to_s).inspect} carries no record of \ - the URL the flow asked for; middleware that rebuilds the request environment is refused. - MESSAGE - end - - unless Discovery.same_origin?(env.url.to_s, requested) - raise DestinationMismatchError, <<~MESSAGE - Request to #{Discovery.canonicalize_origin_and_path(requested).inspect} would be sent to \ - #{Discovery.canonicalize_origin_and_path(env.url.to_s).inspect}, on a different origin; \ - middleware that follows redirects or rewrites URLs is refused. - MESSAGE - end - - @app.call(env) - end - end - private_constant :RequestedURLStamp, :RequestedOriginGuard - - class << self - # Returns why `params` cannot ride a token request as `token_request_params`, or `nil` when it can. - # Shared by the provider constructors and the flow, which both refuse the value with `InvalidTokenRequestParamsError`, - # so the same problem reads the same wherever it surfaces. - def token_request_params_problem(params) - return "must be a Hash (got #{params.class})." unless params.is_a?(Hash) - - # Two equal keys are two entries here, which would be sent twice from a provider method - # or silently collapse into one when the constructors copy the Hash. - return "must not compare keys by identity." if params.compare_by_identity? - - params.each do |key, value| - return "keys must be Strings (got #{key.class})." unless key.is_a?(String) - return "values must be Strings (got #{value.class} for #{key.inspect})." unless value.is_a?(String) - return "must not set #{key.inspect}, which the SDK sets itself." if RESERVED_TOKEN_REQUEST_PARAMS.include?(key) - end - - nil - end - - # Builds the connection the flow uses for its own requests: the SDK's defaults, `RequestedURLStamp`, - # then `customizer` (a provider's `http_client_customizer`, called with the `Faraday::Connection`), - # then `RequestedOriginGuard` last so it sees what the customizer's middleware does to each request - # after the stamp recorded it. Every request on the connection passes through both, so a caller using - # it directly is held to the same origin rule. - # - # Deliberately built without redirect-following middleware. Every destination check in this class runs - # against the URL as written, before the request goes out, so a connection that transparently followed - # a `3xx` would let a server reach a host the checks just refused. The guard turns following at - # the middleware level into a refusal; following inside an adapter stays invisible, so a customizer must - # not enable it. - # - # `Accept-Encoding` is deliberately left unset. `Net::HTTP::GenericRequest` negotiates it and decodes - # the response only while the caller has not claimed that header; assigning it turns `decode_content` off, - # which would silently move `BoundedBody`'s cap onto compressed bytes and let a small body expand past it - # after the check. - def build_http_client(customizer = nil) - require "faraday" - - Faraday.new do |faraday| - faraday.headers["Accept"] = "application/json" - faraday.use(RequestedURLStamp) - customizer&.call(faraday) - faraday.use(RequestedOriginGuard) - end - end - end - - def initialize(provider:, http_client_factory: nil) - @provider = provider - @http_client_factory = http_client_factory || -> { default_http_client } - end - - # Runs the full discovery, registration, authorization, and token exchange flow. - # On success, persists tokens via the provider and returns `:authorized`. - def run!(server_url:, resource_metadata_url: nil, scope: nil) - # The `resource_metadata` URL ships in `WWW-Authenticate` and is the very - # first thing we contact in the OAuth flow, so it has to clear the same - # Communication Security bar as the OAuth endpoints downstream, and it has to - # point back at the server that issued the challenge. - if resource_metadata_url - ensure_secure_url!(resource_metadata_url, label: "WWW-Authenticate resource_metadata URL") - ensure_same_origin!( - resource_metadata_url, - label: "WWW-Authenticate resource_metadata URL", - server_url: server_url, - ) - end - - prm, authorization_server = locate_authorization_server( - server_url: server_url, - resource_metadata_url: resource_metadata_url, - ) - - # Per RFC 8707 + MCP authorization, the canonical MCP server URI is sent on - # both the authorization and token requests. When PRM advertises a `resource`, - # it MUST identify the same MCP server we are talking to; otherwise we are - # being redirected to credentials minted for a different audience. - resource = canonical_resource(server_url: server_url, prm_resource: prm&.dig("resource")) - - as_metadata = authorization_server_metadata( - authorization_server: authorization_server, - legacy: prm.nil?, - server_url: server_url, - ) - - case provider_authorization_flow - when :client_credentials - return run_client_credentials!(as_metadata: as_metadata, prm: prm, resource: resource, scope: scope, server_url: server_url) - when :jwt_bearer - return run_jwt_bearer!(as_metadata: as_metadata, prm: prm, resource: resource, scope: scope, server_url: server_url) - end - - ensure_pkce_supported!(as_metadata) - - effective_scope = resolve_scope(scope: scope, prm: prm) - effective_scope = normalize_offline_access_scope(effective_scope, as_metadata: as_metadata) - - # Asked before registering, not after: a refusal must not leave this client registered at an authorization server - # the embedding application has just rejected. - authorize_request!(as_metadata: as_metadata, scope: effective_scope, server_url: server_url, resource: resource) - - client_info = ensure_client_registered(as_metadata: as_metadata) - - pkce = PKCE.generate - state = SecureRandom.urlsafe_base64(32) - - authorization_url = build_authorization_url( - as_metadata: as_metadata, - client_id: client_info_required_value(client_info, "client_id"), - scope: effective_scope, - state: state, - code_challenge: pkce[:code_challenge], - resource: resource, - ) - - @provider.redirect_handler.call(authorization_url) - callback_result = Array(@provider.callback_handler.call) - code, returned_state, returned_iss = callback_result - raise AuthorizationError, "Authorization callback did not return an authorization code." unless code - - unless states_match?(returned_state, state) - raise AuthorizationError, "OAuth state mismatch (CSRF protection)." - end - - validate_authorization_response_issuer!( - as_metadata: as_metadata, - iss: returned_iss, - iss_provided: callback_result.length >= 3, - ) - - tokens = exchange_authorization_code( - as_metadata: as_metadata, - client_info: client_info, - code: code, - code_verifier: pkce[:code_verifier], - resource: resource, - ) - - save_tokens_issued_by(tokens, as_metadata: as_metadata) - :authorized - end - - # Runs the OAuth 2.1 `client_credentials` grant (machine-to-machine, no user interaction) and persists - # the resulting token. Shares the same discovery and security checks as `run!`; the only difference is - # the grant exchanged at the token endpoint. There is no PKCE, redirect, or authorization request, - # and no `offline_access` augmentation because the grant is not expected to issue a refresh token (OAuth 2.1 Section 4.3.3). - # The pre-registered `client_id` / `client_secret` come from the provider's stored `client_information`. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization - def run_client_credentials!(as_metadata:, prm:, resource:, scope:, server_url:) - client_info = client_credentials_client_info - ensure_client_credentials_issuer!(client_info, as_metadata: as_metadata) - - form = { "grant_type" => "client_credentials" } - effective_scope = resolve_scope(scope: scope, prm: prm) - authorize_request!(as_metadata: as_metadata, scope: effective_scope, server_url: server_url, resource: resource) - form["scope"] = effective_scope if effective_scope - form["resource"] = resource if resource - - tokens = post_to_token_endpoint(as_metadata: as_metadata, client_info: client_info, form: form) - save_tokens_issued_by(tokens, as_metadata: as_metadata) - - :authorized - end - - # Reads the pre-registered credentials for the `client_credentials` grant directly from the provider's stored - # `client_information`, rather than going through `ensure_client_registered` (which targets the authorization-code - # flow and reaches for `Provider`-only methods like `client_metadata` and `client_id_metadata_document_url`). - # The grant is for confidential clients, so a missing `client_id` is a clean configuration error, not a fallback - # to dynamic registration. - def client_credentials_client_info - info = @provider.client_information - unless info.is_a?(Hash) && client_info_required_value(info, "client_id") - raise AuthorizationError, - "Cannot run the client_credentials grant: the provider has no stored `client_id`." - end - - info - end - - # Per SEP-2352, static machine-to-machine credentials are bound to their authorization - # server the same way registered ones are: when the stored `client_information` records - # an `issuer` that differs from the current authorization server, surface an error - # instead of silently sending another server's credentials (the spec's "SHOULD surface - # an error"; the TypeScript SDK raises `AuthorizationServerMismatchError` here). - # Re-registration is not an option for the `client_credentials` grant - the credentials - # are pre-registered, not DCR results - so the operator must update the stored credentials. - # Credentials without a recorded issuer keep working unchanged. - def ensure_client_credentials_issuer!(client_info, as_metadata:) - stored_issuer = client_info_required_value(client_info, "issuer") - return if stored_issuer.nil? - return if stored_issuer == as_metadata["issuer"] - - raise AuthorizationError, - "Stored client credentials are bound to a different authorization server " \ - "(stored issuer #{stored_issuer.inspect}, current #{as_metadata["issuer"].inspect}); " \ - "refusing to send them to the current authorization server (SEP-2352)." - end - - # Runs the RFC 7523 `jwt-bearer` grant for the SEP-990 Enterprise Managed Authorization extension: - # the provider supplies an ID-JAG assertion (typically obtained from an enterprise IdP via `IDJAGTokenExchange`), - # which is presented at the token endpoint with `client_secret_basic` authentication. Shares the same discovery - # and security checks as `run!`; like `client_credentials`, there is no PKCE, redirect, or authorization request. - # The assertion's audience is the issuer identifier that `ensure_issuer_matches!` validated. - # https://github.com/modelcontextprotocol/modelcontextprotocol/issues/990 - def run_jwt_bearer!(as_metadata:, prm:, resource:, scope:, server_url:) - client_info = @provider.client_information - unless client_info.is_a?(Hash) && client_info_required_value(client_info, "client_id") - raise AuthorizationError, "Cannot run the jwt-bearer grant: the provider has no stored `client_id`." - end - - # Asked before the assertion is minted, for the same reason registration waits on the authorization-code grant: - # obtaining an ID-JAG sends the identity provider an audience of this authorization server, which must not happen once - # the host has refused it. - effective_scope = resolve_scope(scope: scope, prm: prm) - authorize_request!(as_metadata: as_metadata, scope: effective_scope, server_url: server_url, resource: resource) - - assertion = @provider.jwt_bearer_assertion(audience: as_metadata["issuer"], resource: resource) - if assertion.nil? || assertion.to_s.empty? - raise AuthorizationError, "The provider's assertion_provider returned no ID-JAG assertion." - end - - form = { - "grant_type" => "urn:ietf:params:oauth:grant-type:jwt-bearer", - "assertion" => assertion, - } - form["scope"] = effective_scope if effective_scope - form["resource"] = resource if resource - - tokens = post_to_token_endpoint(as_metadata: as_metadata, client_info: client_info, form: form) - save_tokens_issued_by(tokens, as_metadata: as_metadata) - :authorized - end - - # Exchanges the saved `refresh_token` for a fresh access token (RFC 6749 Section 6). - # Re-discovers PRM and AS metadata so we always pick up a moved token endpoint, and re-runs the audience / issuer / security - # checks before talking to it. - # - # Returns `:refreshed` on success. Raises `AuthorizationError` when the provider has no refresh token, no client information, - # when a `client_credentials` or `jwt-bearer` provider's tokens record no issuer, - # or when the token endpoint refuses the refresh request. - # https://www.rfc-editor.org/rfc/rfc6749#section-6 - def refresh!(server_url:, resource_metadata_url: nil) - refresh_token = read_token("refresh_token") - raise AuthorizationError, "Cannot refresh: no refresh_token in provider storage." unless refresh_token - - ensure_refresh_token_issuer_recorded! - - stored_client_info = @provider.client_information - have_stored_client_info = stored_client_info.is_a?(Hash) && client_info_required_value(stored_client_info, "client_id") - - # A CIMD-configured provider stores no `client_information` on purpose - # (the CIMD URL is re-resolved against the live AS metadata on every flow). - # Allow refresh to proceed in that case so the `refresh_token` obtained via the CIMD flow remains usable. - have_cimd_url = !provider_client_id_metadata_document_url.nil? - - unless have_stored_client_info || have_cimd_url - raise AuthorizationError, "Cannot refresh: no client_information in provider storage." - end - - if resource_metadata_url - ensure_secure_url!(resource_metadata_url, label: "WWW-Authenticate resource_metadata URL") - ensure_same_origin!( - resource_metadata_url, - label: "WWW-Authenticate resource_metadata URL", - server_url: server_url, - ) - end - - prm, authorization_server = locate_authorization_server( - server_url: server_url, - resource_metadata_url: resource_metadata_url, - ) - - resource = canonical_resource(server_url: server_url, prm_resource: prm&.dig("resource")) - - as_metadata = authorization_server_metadata( - authorization_server: authorization_server, - legacy: prm.nil?, - server_url: server_url, - ) - - ensure_token_issuer!(as_metadata: as_metadata) - - client_info = if have_stored_client_info - # Pre-registered / DCR-issued `client_information` always wins: if the user picked an explicit identity, - # do not silently swap it for the CIMD URL even when the AS also advertises CIMD support. - ensure_refreshable_client_information!(stored_client_info, as_metadata: as_metadata) - stored_client_info - elsif as_metadata["client_id_metadata_document_supported"] == true - { "client_id" => provider_client_id_metadata_document_url } - else - raise AuthorizationError, - "Cannot refresh: provider has a CIMD URL but the authorization server no longer advertises " \ - "`client_id_metadata_document_supported: true`." - end - - new_tokens = exchange_refresh_token( - as_metadata: as_metadata, - client_info: client_info, - refresh_token: refresh_token, - resource: resource, - ) - - save_tokens_issued_by(preserve_refresh_token(new_tokens, refresh_token), as_metadata: as_metadata) - :refreshed - end - - private - - def read_token(key) - tokens = @provider.tokens - return unless tokens.is_a?(Hash) - - value = tokens[key] || tokens[key.to_sym] - value.to_s.empty? ? nil : value - end - - # Per RFC 6749 Section 6, the refresh response MAY omit `refresh_token`, in - # which case the previous one stays valid. Preserve it explicitly so - # downstream refresh attempts still work. - def preserve_refresh_token(new_tokens, previous_refresh_token) - return new_tokens if new_tokens["refresh_token"] || new_tokens[:refresh_token] - - new_tokens.merge("refresh_token" => previous_refresh_token) - end - - def fetch_protected_resource_metadata(server_url:, resource_metadata_url:) - urls = Discovery.protected_resource_metadata_urls( - server_url: server_url, - resource_metadata_url: resource_metadata_url, - ) - fetch_metadata_json(urls, label: "protected resource metadata") - end - - # Locates the authorization server for `server_url` and returns `[prm, authorization_server]`. - # - # Modern path (2025-06-18+): Protected Resource Metadata names the authorization server in - # `authorization_servers`. - # - # Legacy path (2025-03-26 backwards compatibility): when the server publishes no PRM, `prm` is nil - # and the MCP server's own origin acts as the authorization base URL, matching the TypeScript and Python SDKs. - # Only a discovery answer saying that nothing usable is published (`MetadataNotPublishedError`: a `4xx` other than `429`, - # a redirect that was not followed, or a body that is not a JSON object) selects the legacy path. - # A request that failed to reach the server, or returned a `5xx` or `429`, says nothing about what the server publishes, - # so once no candidate has served a usable document it is surfaced instead (`MetadataUnreachableError`), - # as both SDKs do for network errors (the TypeScript SDK outside browsers) and the Python SDK does for server errors. - # A body over the response cap is refused outright and never reaches the fallback either. - # https://modelcontextprotocol.io/specification/2025-03-26/basic/authorization#fallbacks-for-servers-without-metadata-discovery - def locate_authorization_server(server_url:, resource_metadata_url:) - prm = begin - fetch_protected_resource_metadata( - server_url: server_url, - resource_metadata_url: resource_metadata_url, - ) - rescue MetadataNotPublishedError - nil - end - - if prm - authorization_server = first_authorization_server(prm) - ensure_secure_url!(authorization_server, label: "PRM `authorization_servers` entry") - ensure_routable_destination!( - authorization_server, - label: "PRM `authorization_servers` entry", - server_url: server_url, - ) - [prm, authorization_server] - else - authorization_base = server_origin!(server_url) - ensure_secure_url!(authorization_base, label: "MCP server origin (legacy authorization base URL)") - [nil, authorization_base] - end - end - - # Fetches and validates the authorization server's RFC 8414 metadata. - # - # The metadata `issuer` must be byte-identical to the discovery URL (RFC 8414 Section 3.3) on both paths. - # On the legacy 2025-03-26 path the discovery URL is the MCP server's origin, which that spec names as - # the authorization base URL and which a document may render with a trailing slash; the TypeScript and Python SDKs - # accept the same slash-only difference. A document naming any other issuer is refused: an unverified `issuer` - # would otherwise become the identity tokens and client information are bound to, assertions are minted for, - # and the validator is shown, so a server could claim another authorization server and unlock the credentials - # bound to it. - # When even the metadata document is absent, the legacy spec's default endpoints are used. - def authorization_server_metadata(authorization_server:, legacy:, server_url:) - metadata = if legacy - fetched = begin - fetch_authorization_server_metadata(issuer_url: authorization_server) - rescue AuthorizationError - nil - end - - if fetched - ensure_legacy_issuer_matches!(expected: authorization_server, returned: fetched["issuer"]) - fetched - else - default_legacy_metadata(authorization_server) - end - else - fetch_authorization_server_metadata(issuer_url: authorization_server).tap do |fetched| - ensure_issuer_matches!(expected: authorization_server, returned: fetched["issuer"]) - end - end - - ensure_secure_endpoints!(metadata, server_url: server_url) - metadata - end - - # The 2025-03-26 spec's "Fallbacks for Servers without Metadata Discovery": clients MUST use these default endpoint paths - # relative to the authorization base URL. PKCE S256 is assumed because the legacy spec mandates PKCE and there is no metadata - # to advertise it (the TypeScript and Python SDKs hardcode S256 on this path too). - def default_legacy_metadata(authorization_base) - { - "issuer" => authorization_base, - "authorization_endpoint" => "#{authorization_base}/authorize", - "token_endpoint" => "#{authorization_base}/token", - "registration_endpoint" => "#{authorization_base}/register", - "code_challenge_methods_supported" => ["S256"], - } - end - - # Returns `scheme://host[:port]` of `server_url`, the legacy 2025-03-26 authorization base URL for servers without PRM. - def server_origin!(server_url) - uri = URI.parse(server_url.to_s) - unless uri.is_a?(URI::HTTP) && uri.host - raise AuthorizationError, - "Cannot derive a legacy authorization base URL from MCP server URL #{server_url.inspect}." - end - - port_part = uri.port == uri.default_port ? "" : ":#{uri.port}" - "#{uri.scheme}://#{uri.host}#{port_part}" - rescue URI::InvalidURIError => e - raise AuthorizationError, "MCP server URL #{server_url.inspect} is not a valid URI: #{e.message}." - end - - def fetch_authorization_server_metadata(issuer_url:) - urls = Discovery.authorization_server_metadata_urls(issuer_url) - fetch_metadata_json(urls, label: "authorization server metadata") - end - - # The legacy authorization base is an origin, which a document may render as `https://host/`; - # both name the same server, and nothing else does. - def ensure_legacy_issuer_matches!(expected:, returned:) - return if returned == "#{expected}/" - - ensure_issuer_matches!(expected: expected, returned: returned) - end - - # Reads `authorization_servers` from a PRM document and returns - # the first entry, raising `AuthorizationError` for any of the malformed - # shapes a non-compliant server could emit (missing field, non-Array - # value, empty Array, non-String first entry). Centralizing this lets - # both the full flow and the refresh flow share the same defensive - # parse instead of each one duplicating a Hash-and-Array check. - def first_authorization_server(prm) - authorization_servers = prm["authorization_servers"] - unless authorization_servers.is_a?(Array) - raise AuthorizationError, - "Protected resource metadata `authorization_servers` is not an array " \ - "(got #{authorization_servers.class})." - end - - if authorization_servers.empty? - raise AuthorizationError, "Protected resource metadata has no authorization_servers." - end - - first = authorization_servers.first - unless first.is_a?(String) && !first.empty? - raise AuthorizationError, - "Protected resource metadata `authorization_servers[0]` is not a non-empty string." - end - - first - end - - # Walks candidate metadata URLs and returns the parsed body of the first 2xx response that is a JSON object; - # the caller checks its fields. Candidates are tried until one serves such a body, since a later one may still - # be usable when an earlier one is broken or down (the URL from `WWW-Authenticate` against the well-known path, - # or the OAuth document against the OpenID one). Once the candidates are exhausted, an answer that said nothing - # about what is published (a network error, a `5xx`, or a `429`) outranks the rest and raises - # `MetadataUnreachableError`; otherwise (any other status, such as a `4xx` other than `429` or a redirect that - # was not followed, a body that is not JSON, or not a JSON object) `MetadataNotPublishedError`. - # A body over the cap is refused outright by `bounded_request` with a plain `AuthorizationError`, - # before any classification. Each failure is listed with its URL stripped of userinfo, query and fragment - # and cut to `METADATA_URL_MAX_LENGTH`, but otherwise spelled as requested, so it can be matched against - # a server's access log, and with exception text bounded, since the message lands in every log destination - # the error passes through. - def fetch_metadata_json(urls, label:) - failures = [] - inconclusive = false - urls.each do |url| - response = begin - http_get(url) - rescue Faraday::Error => e - detail = bounded_diagnostic(e.message, limit: METADATA_DIAGNOSTIC_MAX_LENGTH) - failures << "GET #{reported_url(url)} raised #{[e.class, detail].compact.join(": ")}" - inconclusive = true - next - end - - unless response.status >= 200 && response.status < 300 - failures << "GET #{reported_url(url)} returned #{response.status}" - inconclusive = true if response.status >= 500 || response.status == 429 - next - end - - parsed = begin - JSON.parse(response_body_string(response)) - rescue JSON::ParserError => e - detail = bounded_diagnostic(e.message, limit: METADATA_DIAGNOSTIC_MAX_LENGTH) || e.class.name - failures << "GET #{reported_url(url)} returned a body that is not JSON: #{detail}" - next - end - - # Even valid JSON can be the wrong shape (a top-level array, a bare `null`, a string, ...). - # The discovery callers index by name (`prm["authorization_servers"]`, etc.), so anything that - # is not a Hash would raise `TypeError` / `NoMethodError` downstream. - unless parsed.is_a?(Hash) - failures << "GET #{reported_url(url)} returned a body that is not a JSON object (got #{parsed.class})" - next - end - - return parsed - end - - message = "Failed to fetch #{label}: #{failures.join("; ")}." - - if inconclusive - raise MetadataUnreachableError, message - else - raise MetadataNotPublishedError, message - end - end - - def ensure_pkce_supported!(as_metadata) - methods = as_metadata["code_challenge_methods_supported"] - return if methods.is_a?(Array) && methods.include?("S256") - - raise AuthorizationError, - "Authorization server does not advertise S256 PKCE support; refusing to proceed." - end - - # Per the MCP authorization spec's Communication Security requirement, - # OAuth endpoints MUST use HTTPS unless the host is a loopback address. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#communication-security - def ensure_secure_url!(url, label:) - return if Discovery.secure_url?(url) - - raise AuthorizationError, - "#{label} #{url.inspect} is not over HTTPS; refusing to use it (MCP authorization Communication Security)." - end - - # Requires a URL the *server* chose to sit on the origin the *caller* chose. - # - # Protected Resource Metadata describes the MCP server itself, so on a real deployment it is - # published on that server's own origin. Without this check a `WWW-Authenticate` challenge - # can aim the first request of the flow at any host the client can route to: the URL arrives - # from the network, it is fetched before the user approves anything, and the `resource` check that - # runs afterwards cannot un-send the request. - # - # RFC 9728 does not itself require the metadata URL to be same-origin, so this is stricter than - # the specification. It is enforced unconditionally because no known deployment publishes its PRM - # anywhere else, and because the alternative (`Discovery.private_network_host?`) cannot see - # internal hosts that are named rather than addressed. - # https://www.rfc-editor.org/rfc/rfc9728#section-7.7 - def ensure_same_origin!(url, label:, server_url:) - return if Discovery.same_origin?(url, server_url) - - raise AuthorizationError, - "#{label} #{sanitized_url(url).inspect} is not on the MCP server origin " \ - "#{sanitized_url(server_url).inspect}; refusing to fetch it." - end - - # Refuses an OAuth URL that points into a private, loopback, link-local, or unique-local address, - # which is the SSRF precaution RFC 9728 Section 7.7 and the MCP security best practices ask clients to take. - # - # The carve-out matters as much as the rule: when the MCP server the caller configured is itself on such an address, - # the whole flow is already inside that network and the authorization server legitimately lives there too. - # That covers `http://localhost` development, the conformance harness (which runs the MCP server and - # the authorization server on two loopback ports), and deployments that never leave a corporate network. - # Only a server reachable on the public internet is barred from steering the client inward. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization - # Hands the embedding application the authorization server and the scopes that are about to be requested, - # and abandons the flow when it refuses them. - # - # Both values are chosen by the MCP server: it names its own authorization server in Protected - # Resource Metadata and states the scopes in `scopes_supported` or the `WWW-Authenticate` challenge. - # Neither the specification nor any MCP SDK binds that choice to the server's own identity, - # and validating that a token was issued for the intended audience is a responsibility the specification - # places on MCP servers rather than on clients. - # A host that knows which providers its user deals with can apply that knowledge here. - # - # The scopes are passed on unchanged whatever the host decides, because the specification requires - # a client to treat the challenged scopes as authoritative for the operation; the choice offered is - # to proceed or to stop, not to quietly ask for less. A provider without the hook proceeds as before. - # - # Only asked when a new grant is being requested. A refresh is not a new grant, and the host already answered - # this question for that authorization server, so `refresh!` enforces `ensure_token_issuer!` instead: - # an authorization server that has changed since the tokens were issued sends the flow back through here, - # where the host sees the new one and decides again. - def authorize_request!(as_metadata:, scope:, server_url:, resource:) - return unless @provider.respond_to?(:authorization_request_validator) - return unless (validator = @provider.authorization_request_validator) - - request = AuthorizationRequest.new( - authorization_server: as_metadata["issuer"], - scopes: scope.to_s.split, - server_url: server_url, - resource: resource, - ).freeze - - return if validator.call(request) - - raise AuthorizationRefusedError, <<~MESSAGE - The authorization request was refused by `authorization_request_validator` \ - (authorization server #{request.authorization_server.inspect}, scopes #{request.scopes.inspect}). - MESSAGE - end - - def ensure_routable_destination!(url, label:, server_url:) - return unless private_network_url?(url) - return if private_network_url?(server_url) - - raise AuthorizationError, - "#{label} #{sanitized_url(url).inspect} points into a private network range, " \ - "which the MCP server at #{sanitized_url(server_url).inspect} is not on; refusing to contact it." - end - - def ensure_secure_endpoints!(as_metadata, server_url:) - ["authorization_endpoint", "token_endpoint", "registration_endpoint"].each do |key| - endpoint = as_metadata[key] - next unless endpoint - - ensure_secure_url!(endpoint, label: "Authorization server #{key}") - ensure_routable_destination!(endpoint, label: "Authorization server #{key}", server_url: server_url) - end - end - - # `ensure_secure_url!` runs first at every call site and already rejects a URL that fails to parse, - # so the rescue here is a backstop rather than a leniency. - def private_network_url?(url) - Discovery.private_network_host?(URI.parse(url.to_s).host) - rescue URI::InvalidURIError - false - end - - # Strips userinfo and query before a URL reaches an exception message, the same precaution `MCP::Client::HTTP` takes - # when it reports a URL: these values come off the network and can carry credentials that would otherwise land in - # every log destination the error passes through. - def sanitized_url(url) - Discovery.canonicalize_origin_and_path(url) - rescue URI::Error - url.to_s - end - - # Per RFC 8414 Section 3.3, the AS metadata document's `issuer` value MUST be - # identical (literal byte-for-byte equality, no normalization) to - # the issuer URL the client used to discover that document. This guards - # against a CDN/relay returning the metadata of a *different* - # authorization server than the one PRM advertised, and against - # ambiguities like trailing `/`, fragments, or case differences that - # could mask a confused-deputy attempt. - # https://www.rfc-editor.org/rfc/rfc8414#section-3.3 - def ensure_issuer_matches!(expected:, returned:) - unless returned - raise AuthorizationError, "Authorization server metadata is missing the `issuer` field." - end - - return if expected.to_s == returned.to_s - - raise AuthorizationError, - "Authorization server metadata `issuer` does not match the discovery URL " \ - "(expected #{expected.inspect}, got #{returned.inspect})." - end - - def ensure_client_registered(as_metadata:) - existing = stored_client_information_for(issuer: as_metadata["issuer"]) - return existing if existing - - # Per the MCP authorization specification and `draft-ietf-oauth-client-id-metadata-document`, - # if the authorization server advertises Client ID Metadata Document support and the provider has - # a CIMD URL configured, use the URL as the OAuth `client_id` and skip Dynamic Client Registration. - # - # The `== true` comparison is intentional: only a JSON `boolean` `true` opts the flow in. - # A string `"false"`, an empty Hash, or any other truthy value MUST NOT be treated as CIMD support, - # otherwise a misconfigured AS could trick the client into using the CIMD `client_id` against - # a server that has not actually adopted it. - # - # The CIMD `client_id` is NOT persisted to storage. The AS may later stop advertising CIMD support - # (or the operator may rotate the CIMD URL), and a stale `client_information` entry would otherwise - # keep sending the old CIMD URL forever. Re-evaluating on every flow re-reads the current AS metadata - # and the current `provider.client_id_metadata_document_url`. - cimd_url = provider_client_id_metadata_document_url - if cimd_url && as_metadata["client_id_metadata_document_supported"] == true - return { "client_id" => cimd_url } - end - - registration_endpoint = as_metadata["registration_endpoint"] - unless registration_endpoint - raise AuthorizationError, - "Authorization server has no registration_endpoint and no pre-registered client information was provided." - end - - response = begin - http_post_json(registration_endpoint, registration_client_metadata) - rescue Faraday::Error => e - raise AuthorizationError, - "Dynamic client registration failed: #{e.class}: #{e.message}." - end - - if response.status < 200 || response.status >= 300 - raise AuthorizationError, "Dynamic client registration failed with status #{response.status}." - end - - info = begin - JSON.parse(response_body_string(response)) - rescue JSON::ParserError => e - raise AuthorizationError, - "Failed to parse dynamic client registration response: #{e.message}." - end - - unless info.is_a?(Hash) && client_info_required_value(info, "client_id") - raise AuthorizationError, - "Dynamic client registration response is missing `client_id`." - end - - # Per SEP-2352, persisted client credentials are keyed by the issuer identifier of - # the authorization server that minted them, so a later flow can detect an AS change and - # re-register instead of replaying another server's credentials. `issuer` is not an RFC 7591 response field; - # the SDK adds it to the opaque persisted hash. - @provider.save_client_information(info.merge("issuer" => as_metadata["issuer"])) - - info - end - - # Returns the client metadata to submit on Dynamic Client Registration. - # Per SEP-837, MCP clients MUST specify an appropriate OIDC `application_type` - # so the authorization server can apply the matching redirect URI policy. - # When the user did not set one explicitly, infer `"native"` vs `"web"` from - # the registered `redirect_uris`; an explicit value always wins. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/837 - def registration_client_metadata - metadata = @provider.client_metadata - return metadata if metadata[:application_type] || metadata["application_type"] - - redirect_uris = metadata[:redirect_uris] || metadata["redirect_uris"] - metadata.merge("application_type" => Discovery.infer_application_type(redirect_uris)) - end - - # Returns the stored `client_information` when it may be used against the authorization server - # identified by `issuer`, applying SEP-2352's authorization server binding rules: - # - # - Credentials persisted with an `"issuer"` binding MUST NOT be reused against - # a different authorization server. When the AS changed, the stale registration and its tokens - # are discarded (tokens minted by the old AS are dead at the new one) and nil is returned so - # the flow re-registers. - # - Stored credentials without an `"issuer"` binding (data persisted by an older SDK version, - # or user-supplied pre-registered credentials) are bound to the current issuer on first use. - # - A CIMD `client_id` (an HTTPS URL) is portable across authorization servers, so it is reused - # and re-bound instead of discarded. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2352 - def stored_client_information_for(issuer:) - existing = @provider.client_information - return unless existing.is_a?(Hash) && client_info_required_value(existing, "client_id") - - stored_issuer = client_info_required_value(existing, "issuer") - return existing if stored_issuer == issuer - return rebind_client_information(existing, issuer: issuer) if stored_issuer.nil? - - client_id = client_info_required_value(existing, "client_id") - return rebind_client_information(existing, issuer: issuer) if Discovery.client_id_metadata_document_url?(client_id) - - @provider.save_client_information(nil) - @provider.clear_tokens! - nil - end - - def rebind_client_information(info, issuer:) - rebound = info.merge("issuer" => issuer) - @provider.save_client_information(rebound) - rebound - end - - # Per SEP-2352, stored client credentials are bound to the authorization server that issued them; - # refuse to replay another AS's credentials at this token endpoint. `HTTP#attempt_refresh` rescues - # the error and falls back to the full flow, which discards the stale registration and re-registers. - # Credentials without an `"issuer"` binding predate this check and are allowed through; - # CIMD `client_id`s are portable. - # Records which authorization server minted these tokens, alongside the tokens themselves. - # SEP-2352 already binds *client credentials* to their issuer; this binds the *tokens*, which that - # SEP leaves unbound. - # Stored in the token hash so it travels through any `storage` a caller supplied, without widening - # the storage interface that custom implementations have to satisfy. - def save_tokens_issued_by(tokens, as_metadata:) - issuer = as_metadata["issuer"] - tokens = tokens.merge("issuer" => issuer) if tokens.is_a?(Hash) && issuer - - @provider.save_tokens(tokens) - end - - # Refuses to present a refresh token to an authorization server other than the one that issued it. - # `refresh!` rediscovers the authorization server from Protected Resource Metadata every time, - # so the server named for a session can differ from the one the stored tokens came from. - # Unlike `ensure_refreshable_client_information!` this holds whatever the client identity is, - # including a Client ID Metadata Document URL, which is portable across authorization servers precisely - # so that re-registration is unnecessary. - # - # Tokens stored before this shipped carry no issuer and are left alone, matching how SEP-2352 treats - # client information without one; the binding takes effect from their next authorization. - # The caller answers a refusal by running the full authorization flow, which is where the embedding application - # is asked about the new authorization server. - def ensure_token_issuer!(as_metadata:) - stored_issuer = read_token("issuer") - return if stored_issuer.nil? || stored_issuer == as_metadata["issuer"] - - raise AuthorizationError, <<~MESSAGE - Cannot refresh: the stored tokens were issued by a different authorization server (stored issuer #{stored_issuer.inspect}, \ - current #{as_metadata["issuer"].inspect}); re-authorization is required. - MESSAGE - end - - # `Provider` tolerates tokens stored before the issuer was recorded (see `ensure_token_issuer!`). - # The `client_credentials` and `jwt-bearer` providers have no such tokens, since their refresh is new, - # and a refresh asks no validator, so a token without an `issuer` would be presented to whatever - # authorization server discovery names now. Refusing it sends the transport back through the grant, - # which does ask. - def ensure_refresh_token_issuer_recorded! - return if provider_authorization_flow == :authorization_code - return unless read_token("issuer").nil? - - raise AuthorizationError, "Cannot refresh: the stored tokens record no issuer; re-authorization is required." - end - - def ensure_refreshable_client_information!(client_info, as_metadata:) - stored_issuer = client_info_required_value(client_info, "issuer") - return if stored_issuer.nil? - return if stored_issuer == as_metadata["issuer"] - - client_id = client_info_required_value(client_info, "client_id") - return if Discovery.client_id_metadata_document_url?(client_id) - - raise AuthorizationError, - "Cannot refresh: stored client credentials were issued by a different authorization server " \ - "(stored issuer #{stored_issuer.inspect}, current #{as_metadata["issuer"].inspect}); " \ - "re-registration is required (SEP-2352)." - end - - # Reads `key` from a `client_information` hash that may use either string or - # symbol keys, so users can persist the result of `JSON.parse` *or* a hand-built - # `{ client_id:, client_secret: }` and have both work. - def client_info_value(info, key) - info[key] || info[key.to_sym] - end - - # Same as `client_info_value` but treats blank strings (`""` or only - # whitespace) as absent. Used for fields where empty values are never - # meaningful (`client_id`, `client_secret`, `token_endpoint_auth_method`) - # and would otherwise let a misbehaving AS or hand-built - # `client_information` short-circuit the "is the client registered?" - # check, or send a literal `client_secret: " "` to the token endpoint. - def client_info_required_value(info, key) - value = client_info_value(info, key) - return if value.nil? - return if value.is_a?(String) && value.strip.empty? - - value - end - - # Returns the canonical RFC 8707 `resource` URI to send on authorization and - # token requests. When PRM advertises `resource`, that value is - # the authorization server's idea of the resource identifier and is preferred. - # When PRM omits it, the canonicalized MCP server URL is used. - # - # Either way, we validate that PRM's `resource` covers the MCP server URL - # the client is actually talking to (same origin, with PRM's path as a prefix of - # the server URL's path) to prevent a malicious or misconfigured PRM from - # redirecting credentials to a different audience. - def canonical_resource(server_url:, prm_resource:) - server_canonical = safe_canonicalize_url(server_url, label: "MCP server URL") - return server_canonical unless prm_resource - - prm_canonical = safe_canonicalize_url(prm_resource, label: "PRM `resource`") - unless Discovery.resource_covers?(prm: prm_canonical, server: server_canonical) - raise AuthorizationError, - "Protected resource metadata `resource` does not match the MCP server URL " \ - "(server=#{server_canonical}, prm=#{prm_canonical})." - end - - prm_canonical - end - - # Wraps `Discovery.canonicalize_url` so that any URI parsing failure - # caused by malformed input from the server (`PRM.resource`, AS metadata - # endpoints, ...) surfaces as `AuthorizationError` instead of leaking - # a raw `URI::InvalidURIError` / `ArgumentError`. - def safe_canonicalize_url(url, label:) - Discovery.canonicalize_url(url) - rescue URI::InvalidURIError, ArgumentError => e - raise AuthorizationError, "#{label} #{url.inspect} is not a valid URI: #{e.message}." - end - - # Validates the RFC 9207 `iss` authorization response parameter against the issuer of the authorization server - # the flow is talking to, per SEP-2468 (mix-up attack mitigation in multi-IdP setups): - # - # - When the callback supplied a non-empty `iss`, it MUST equal the AS metadata `issuer` exactly (simple string comparison, - # no normalization, per RFC 9207 Section 2.4); on mismatch the flow aborts before the authorization code is ever sent to - # a token endpoint. - # - When the callback returned a 3-element `[code, state, iss]` whose `iss` is nil (asserting it inspected the authorization response - # and found no `iss`) and the AS metadata advertises `authorization_response_iss_parameter_supported: true`, the missing parameter - # is treated as an attack per RFC 9207 Section 2.4 and the flow aborts. - # - A legacy 2-element `[code, state]` callback skips the check: the caller never looked for `iss`, so its absence carries no signal. - # - # `as_metadata["issuer"]` has already been byte-compared against the discovery URL by `ensure_issuer_matches!`, - # so it is the RFC 9207 anchor value. `iss` is not a secret; a plain `==` suffices. - # - # - https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2468 - # - https://www.rfc-editor.org/rfc/rfc9207 - def validate_authorization_response_issuer!(as_metadata:, iss:, iss_provided:) - expected = as_metadata["issuer"] - - if iss && !iss.to_s.empty? - return if iss.to_s == expected.to_s - - raise AuthorizationError, - "Authorization response `iss` does not match the authorization server issuer " \ - "(expected #{expected.inspect}, got #{iss.inspect}) (RFC 9207); " \ - "refusing to exchange the authorization code." - end - - return unless iss_provided - return unless as_metadata["authorization_response_iss_parameter_supported"] == true - - raise AuthorizationError, - "Authorization server advertises `authorization_response_iss_parameter_supported` but " \ - "the authorization response carried no `iss` parameter (RFC 9207 Section 2.4); " \ - "refusing to exchange the authorization code." - end - - # Constant-time comparison for the OAuth `state` parameter to prevent timing-based discovery - # of the expected value. - # `OpenSSL.fixed_length_secure_compare` would be ideal, but it is not available on Ruby 2.7 - # (the project's minimum supported version). - # The hand-rolled XOR-sum walks every byte of the equal-length operands, so the running time - # does not leak the position of the first mismatching byte. - def states_match?(returned, expected) - returned = returned.to_s - return false unless returned.bytesize == expected.bytesize - - result = 0 - returned.bytes.zip(expected.bytes) { |a, b| result |= a ^ b } - result.zero? - end - - # Per MCP 2025-11-25 Authorization and the TS/Python SDKs, scope resolution - # prefers the `WWW-Authenticate` challenge first, then `scopes_supported` - # from the Protected Resource Metadata, and falls back to a provider-supplied - # scope only if both are absent. The provider-supplied scope must not pre-empt - # a server-advertised one. - def resolve_scope(scope:, prm:) - return scope if scope && !scope.empty? - - # `prm` is nil on the legacy path, where nothing advertises scopes. - supported = prm && prm["scopes_supported"] - return supported.join(" ") if supported.is_a?(Array) && !supported.empty? - - return @provider.scope if @provider.scope && !@provider.scope.empty? - - nil - end - - # Applies the SDK's `offline_access` policy to the resolved scope. The policy has two halves: - # - # - Spec (SEP-2207): a client that wants a refresh token (signalled here by listing - # `refresh_token` in its registered `grant_types`) MAY request `offline_access` - # when the authorization server advertises it in metadata `scopes_supported`. - # When the server advertises it and the client opted in, add it if absent. - # - # - SDK policy (defensive hardening): when the server does NOT advertise `offline_access`, - # strip it from the resolved scope no matter where it came from (the `WWW-Authenticate` challenge, - # PRM `scopes_supported`, or the provider-supplied scope). SEP-2207 only says clients SHOULD NOT - # request unsupported scopes, but a misbehaving RS that includes `offline_access` in its challenge, - # or a misconfigured PRM that lists it under `scopes_supported`, would otherwise propagate into - # the authorization request even though the AS will not honour it. Stripping here keeps the SDK's - # own request consistent with the AS's advertisement. - # - # Returns `nil` when the result is empty so `build_authorization_url` omits the `scope` parameter entirely. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2207 - def normalize_offline_access_scope(scope, as_metadata:) - scopes = scope.to_s.split - - if server_supports_offline_access?(as_metadata) - scopes << "offline_access" if wants_refresh_token? && !scopes.include?("offline_access") - else - scopes.delete("offline_access") - end - - scopes.empty? ? nil : scopes.join(" ") - end - - def server_supports_offline_access?(as_metadata) - supported = as_metadata["scopes_supported"] - - supported.is_a?(Array) && supported.include?("offline_access") - end - - def wants_refresh_token? - metadata = @provider.client_metadata - grant_types = metadata[:grant_types] || metadata["grant_types"] - - Array(grant_types).include?("refresh_token") - end - - # The OAuth flow the provider drives. Dispatching on the provider's - # declared flow keeps `Flow` from second-guessing intent by parsing - # `client_metadata[:grant_types]` (which is protocol metadata for the - # authorization server, not an SDK control signal). A provider that - # predates this method is treated as the interactive authorization-code - # flow it was the only option for. - def provider_authorization_flow - return :authorization_code unless @provider.respond_to?(:authorization_flow) - - @provider.authorization_flow - end - - # Parameters the provider adds to every token request it makes (RFC 6749 Section 8.2 leaves room for them; - # Auth0's `audience` is the usual one). Duck-typed like `authorization_flow`, so a provider without the method, - # or one returning `nil`, adds nothing. - # A bad value raises `InvalidTokenRequestParamsError`, as the provider constructors do. - def provider_token_request_params - return {} unless @provider.respond_to?(:token_request_params) - - params = @provider.token_request_params - return {} if params.nil? - - problem = self.class.token_request_params_problem(params) - raise InvalidTokenRequestParamsError, "The provider's token_request_params #{problem}" if problem - - params - end - - # The Client ID Metadata Document URL, when the provider has one. Only `Provider` exposes the reader - # (CIMD replaces Dynamic Client Registration on the authorization-code flow), while `refresh!` serves - # every provider that holds a `refresh_token`, so the read is duck-typed like `authorization_flow`. - def provider_client_id_metadata_document_url - return unless @provider.respond_to?(:client_id_metadata_document_url) - - @provider.client_id_metadata_document_url - end - - def build_authorization_url(as_metadata:, client_id:, scope:, state:, code_challenge:, resource:) - authorization_endpoint = as_metadata["authorization_endpoint"] - unless authorization_endpoint - raise AuthorizationError, - "Authorization server metadata is missing `authorization_endpoint`." - end - - uri = begin - URI.parse(authorization_endpoint) - rescue URI::InvalidURIError => e - raise AuthorizationError, - "Authorization server metadata `authorization_endpoint` is not a valid URI: #{e.message}." - end - - params = URI.decode_www_form(uri.query.to_s) - params << ["response_type", "code"] - params << ["client_id", client_id] - params << ["redirect_uri", @provider.redirect_uri] - params << ["code_challenge", code_challenge] - params << ["code_challenge_method", "S256"] - params << ["state", state] - params << ["scope", scope] if scope - params << ["resource", resource] if resource - uri.query = URI.encode_www_form(params) - uri - end - - def exchange_authorization_code(as_metadata:, client_info:, code:, code_verifier:, resource:) - form = { - "grant_type" => "authorization_code", - "code" => code, - "redirect_uri" => @provider.redirect_uri, - "code_verifier" => code_verifier, - } - form["resource"] = resource if resource - - post_to_token_endpoint(as_metadata: as_metadata, client_info: client_info, form: form) - end - - def exchange_refresh_token(as_metadata:, client_info:, refresh_token:, resource:) - form = { - "grant_type" => "refresh_token", - "refresh_token" => refresh_token, - } - form["resource"] = resource if resource - - post_to_token_endpoint(as_metadata: as_metadata, client_info: client_info, form: form) - end - - # Submits a form-encoded token request using the authentication method - # stored in `client_information`. The method determines whether client - # credentials belong in the form body, a Basic header, or a JWT assertion. - # A provider's `token_request_params` go underneath the flow's own parameters, - # which therefore win, and are refused before the request is sent when they name - # a reserved parameter or are not a Hash of Strings. - def post_to_token_endpoint(as_metadata:, client_info:, form:) - client_id = client_info_required_value(client_info, "client_id") - unless client_id - raise AuthorizationError, - "Cannot post to token endpoint: client_information is missing `client_id`." - end - - client_secret = client_info_required_value(client_info, "client_secret") - token_endpoint_auth_method = client_info_value(client_info, "token_endpoint_auth_method") - form = provider_token_request_params.merge(form) - - # Apply one client authentication method per request (RFC 6749 Section 2.3). - headers = {} - form = case token_endpoint_auth_method - when "private_key_jwt" - # The assertion identifies the client through its `iss` and `sub` - # claims, so the body needs no separate `client_id` (RFC 7521 Section 4.2). - # Use the issuer already checked by `ensure_issuer_matches!` as the audience. - unless @provider.respond_to?(:client_assertion) - raise AuthorizationError, - "token_endpoint_auth_method is private_key_jwt but the provider does not " \ - "implement `client_assertion(audience:)`." - end - - form.merge( - "client_assertion_type" => JWTClientAssertion::ASSERTION_TYPE, - "client_assertion" => @provider.client_assertion(audience: as_metadata["issuer"]), - ) - when "client_secret_post" - # Send the client ID and available secret in the form body. - body = form.merge("client_id" => client_id) - body["client_secret"] = client_secret if client_secret - body - else - if client_secret && token_endpoint_auth_method != "none" - # Basic is also the fallback when a secret is present but no method - # is stored. A body `client_id` is optional (RFC 6749 Section 3.2.1); - # omit it because some servers treat it alongside Basic as a second - # authentication method and reject the request with `invalid_request`. - headers["Authorization"] = "Basic " + basic_auth_credentials(client_id, client_secret) - form - else - # With `none` or no secret, identify the client using `client_id`. - # This is required for unauthenticated authorization-code exchanges - # (RFC 6749 Section 3.2.1). - form.merge("client_id" => client_id) - end - end - - token_endpoint = as_metadata["token_endpoint"] - unless token_endpoint - raise AuthorizationError, - "Authorization server metadata is missing `token_endpoint`." - end - - response = begin - http_post_form(token_endpoint, form, headers: headers) - rescue Faraday::Error => e - raise AuthorizationError, - "Token request to #{token_endpoint} failed: #{e.class}: #{e.message}." - end - - if response.status < 200 || response.status >= 300 - raise token_endpoint_error(response) - end - - parsed = begin - JSON.parse(response_body_string(response)) - rescue JSON::ParserError => e - raise AuthorizationError, "Failed to parse token endpoint response: #{e.message}." - end - - # Token responses MUST be a JSON object per RFC 6749 §5.1. Anything - # else (`null`, `[]`, a bare string) would otherwise be persisted - # as `provider.tokens` and raise raw `NoMethodError` / `TypeError` - # the next time `provider.access_token` is read. - unless parsed.is_a?(Hash) - raise AuthorizationError, - "Token endpoint response is not a JSON object (got #{parsed.class})." - end - - parsed - end - - # Surface only RFC 6749 §5.2 diagnostic fields, never the raw response, - # which may contain tokens or other credentials. Classify the original - # code so sanitization cannot turn malformed input into invalid_grant. - def token_endpoint_error(response) - message = "Token endpoint returned status #{response.status}." - error_class = AuthorizationError - parsed = JSON.parse(response_body_string(response)) - parsed = {} unless parsed.is_a?(Hash) - - error_class = parsed["error"] == "invalid_grant" ? InvalidGrantError : AuthorizationError - error = bounded_diagnostic(parsed["error"], limit: TOKEN_ENDPOINT_ERROR_MAX_LENGTH) - description = bounded_diagnostic(parsed["error_description"], limit: TOKEN_ENDPOINT_ERROR_DESCRIPTION_MAX_LENGTH) - message += " #{[error, description].compact.join(": ")}" if error || description - - error_class.new(message, http_status: response.status, error: error, error_description: description) - rescue StandardError - # Diagnostics must not mask the endpoint failure or change refresh recovery. - error_class.new("Token endpoint returned status #{response.status}.", http_status: response.status) - end - - def bounded_diagnostic(value, limit:) - return unless value.is_a?(String) - - # RFC 6749 permits printable ASCII except double quotes and backslashes in token endpoint error fields. - # Replace other characters to keep text received off the network on one log line. - value = value.scrub(" ").gsub(/[^\x20-\x21\x23-\x5B\x5D-\x7E]/, " ").strip - return if value.empty? - - value.length > limit ? "#{value[0, limit - 3]}..." : value - end - - # A candidate URL as it goes into a failure string: redacted, and cut so a URL the server chose cannot - # grow the message without limit. - def reported_url(url) - bounded_diagnostic(Discovery.redact_url(url), limit: METADATA_URL_MAX_LENGTH) - end - - # Per RFC 6749 Section 2.3.1, the `client_id` and `client_secret` MUST be - # `application/x-www-form-urlencoded` encoded before they are joined with - # `:` and base64-encoded for the `Authorization: Basic` header. This is - # what prevents credentials containing `:` or other special characters - # from being mis-parsed by the authorization server. - # https://www.rfc-editor.org/rfc/rfc6749#section-2.3.1 - def basic_auth_credentials(client_id, client_secret) - encoded_id = URI.encode_www_form_component(client_id) - encoded_secret = URI.encode_www_form_component(client_secret) - Base64.strict_encode64("#{encoded_id}:#{encoded_secret}") - end - - def http_get(url) - bounded_request do |on_data| - http_client.get(url) do |req| - req.options.on_data = on_data - end - end - end - - def http_post_json(url, body) - bounded_request do |on_data| - http_client.post(url) do |req| - req.headers["Content-Type"] = "application/json" - req.headers["Accept"] = "application/json" - req.options.on_data = on_data - req.body = JSON.generate(body) - end - end - end - - def http_post_form(url, form, headers: {}) - bounded_request do |on_data| - http_client.post(url) do |req| - req.headers["Content-Type"] = "application/x-www-form-urlencoded" - req.headers["Accept"] = "application/json" - - headers.each do |key, value| - req.headers[key] = value - end - - req.options.on_data = on_data - req.body = URI.encode_www_form(form) - end - end - end - - # Issues a request with the response body bounded as it arrives, and returns the status paired with - # that body. An over-cap response is refused rather than truncated: a partial discovery or token document - # cannot be validated, and `fetch_metadata_json` must not fall through to the next candidate URL either, - # since the same server would serve the same body. - def bounded_request - bounded = BoundedBody.new - - response = yield(bounded.on_data) - - bounded.response_for(response) - rescue BoundedBody::TooLargeError => e - raise AuthorizationError, "#{e.message}." - end - - def http_client - @http_client ||= @http_client_factory.call - end - - # A connection supplied through `http_client_factory:` replaces this one, the provider's customizer and - # `RequestedOriginGuard` included, so that caller takes on the redirect responsibility described on - # `build_http_client`; `bounded_request` caps its responses all the same. - def default_http_client - self.class.build_http_client(provider_http_client_customizer) - end - - # `nil` for a provider that predates the hook or leaves it unset. - def provider_http_client_customizer - return unless @provider.respond_to?(:http_client_customizer) - - @provider.http_client_customizer - end - - def response_body_string(response) - body = response.body - body.is_a?(String) ? body : body.to_s - end - end - end - end -end diff --git a/lib/mcp/client/oauth/id_jag_token_exchange.rb b/lib/mcp/client/oauth/id_jag_token_exchange.rb deleted file mode 100644 index ea771a9..0000000 --- a/lib/mcp/client/oauth/id_jag_token_exchange.rb +++ /dev/null @@ -1,112 +0,0 @@ -# frozen_string_literal: true - -require "json" -require "uri" - -module MCP - class Client - module OAuth - # RFC 8693 token exchange against an enterprise identity provider, turning an IdP-issued ID token into - # an Identity Assertion Authorization Grant (ID-JAG) per the MCP Enterprise Managed Authorization extension (SEP-990). - # The returned ID-JAG is an opaque assertion the client then presents to the MCP authorization server with - # the RFC 7523 `jwt-bearer` grant (see `CrossAppAccessProvider`). - # Mirrors `requestJwtAuthorizationGrant` in the TypeScript SDK. - # - # - https://github.com/modelcontextprotocol/modelcontextprotocol/issues/990 - # - https://www.rfc-editor.org/rfc/rfc8693 - module IDJAGTokenExchange - # Raised when the identity provider's token exchange fails or returns something other than an ID-JAG. - class ExchangeError < StandardError; end - - GRANT_TYPE = "urn:ietf:params:oauth:grant-type:token-exchange" - ID_TOKEN_TYPE = "urn:ietf:params:oauth:token-type:id_token" - ID_JAG_TOKEN_TYPE = "urn:ietf:params:oauth:token-type:id-jag" - - class << self - # Exchanges `id_token` for an ID-JAG at the IdP's token endpoint and returns the assertion string. - # - # @param token_endpoint [String] The identity provider's token endpoint. - # @param id_token [String] The IdP-issued ID token (the subject token). - # @param client_id [String] The client's identifier at the IdP. - # @param audience [String] The MCP authorization server's issuer identifier. - # @param resource [String] The canonical MCP server URL (RFC 8707). - # @param http_client [Object, nil] Faraday-compatible client; built lazily by default. - def request(token_endpoint:, id_token:, client_id:, audience:, resource:, http_client: nil) - http_client ||= default_http_client - - bounded = BoundedBody.new - - response = begin - raw_response = http_client.post(token_endpoint) do |req| - req.headers["Content-Type"] = "application/x-www-form-urlencoded" - req.headers["Accept"] = "application/json" - req.options.on_data = bounded.on_data - req.body = URI.encode_www_form( - "grant_type" => GRANT_TYPE, - "subject_token" => id_token, - "subject_token_type" => ID_TOKEN_TYPE, - "requested_token_type" => ID_JAG_TOKEN_TYPE, - "audience" => audience, - "resource" => resource, - "client_id" => client_id, - ) - end - - bounded.response_for(raw_response) - rescue BoundedBody::TooLargeError => e - raise ExchangeError, "#{e.message}." - rescue Faraday::Error => e - raise ExchangeError, "Token exchange request to #{token_endpoint} failed: #{e.class}: #{e.message}." - end - - if response.status < 200 || response.status >= 300 - raise ExchangeError, "Identity provider token exchange returned status #{response.status}." - end - - parse_id_jag(response) - end - - private - - def parse_id_jag(response) - body = response.body.is_a?(String) ? response.body : response.body.to_s - parsed = begin - JSON.parse(body) - rescue JSON::ParserError => e - raise ExchangeError, "Failed to parse token exchange response: #{e.message}." - end - - unless parsed.is_a?(Hash) - raise ExchangeError, "Token exchange response is not a JSON object (got #{parsed.class})." - end - - issued_token_type = parsed["issued_token_type"] - unless issued_token_type == ID_JAG_TOKEN_TYPE - raise ExchangeError, - "Token exchange did not issue an ID-JAG " \ - "(expected issued_token_type #{ID_JAG_TOKEN_TYPE.inspect}, got #{issued_token_type.inspect})." - end - - assertion = parsed["access_token"] - if assertion.nil? || assertion.to_s.empty? - raise ExchangeError, "Token exchange response is missing `access_token`." - end - - assertion - end - - # `Accept-Encoding` is deliberately left unset, for the same reason as `Flow.build_http_client`: - # claiming that header turns Net::HTTP's `decode_content` off and would move `BoundedBody`'s cap - # onto compressed bytes. - def default_http_client - require "faraday" - - Faraday.new do |faraday| - faraday.headers["Accept"] = "application/json" - end - end - end - end - end - end -end diff --git a/lib/mcp/client/oauth/in_memory_storage.rb b/lib/mcp/client/oauth/in_memory_storage.rb deleted file mode 100644 index 23edad9..0000000 --- a/lib/mcp/client/oauth/in_memory_storage.rb +++ /dev/null @@ -1,45 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # Default reference implementation of the storage contract that - # `Provider` uses to persist OAuth state. Holds the two pieces of data - # the flow saves and reads on every request: - # - # - `tokens`: the hash returned by the token endpoint - # (`access_token`, optional `refresh_token`, `expires_in`, `scope`, etc.). - # - `client_information`: the hash returned by Dynamic Client Registration - # or supplied as pre-registered credentials - # (`client_id`, optional `client_secret`, optional - # `token_endpoint_auth_method`). The SDK additionally stamps an `"issuer"` member - # binding the credentials to the authorization server that issued them (SEP-2352); - # custom storages should treat the hash as opaque and persist it as-is. - # - # This class keeps everything in process memory, so the credentials live - # only for the lifetime of the Ruby process. Applications that need - # persistence across restarts should supply a custom object responding to - # the same four-method contract (`tokens`, `save_tokens(t)`, - # `client_information`, `save_client_information(info)`) and pass it via - # `Provider.new(storage: ...)`. The shape mirrors Python SDK's - # `TokenStorage` Protocol; TypeScript's `OAuthClientProvider` rolls - # the same responsibilities into a single object. - class InMemoryStorage - attr_accessor :tokens, :client_information - - def initialize - @tokens = nil - @client_information = nil - end - - def save_tokens(tokens) - @tokens = tokens - end - - def save_client_information(info) - @client_information = info - end - end - end - end -end diff --git a/lib/mcp/client/oauth/jwt_client_assertion.rb b/lib/mcp/client/oauth/jwt_client_assertion.rb deleted file mode 100644 index 5311a05..0000000 --- a/lib/mcp/client/oauth/jwt_client_assertion.rb +++ /dev/null @@ -1,128 +0,0 @@ -# frozen_string_literal: true - -require "base64" -require "json" -require "openssl" -require "securerandom" - -module MCP - class Client - module OAuth - # Builds RFC 7523 Section 2.2 JWT client assertions for the `private_key_jwt` - # client authentication method used by the `client_credentials` grant - # (MCP extension `io.modelcontextprotocol/oauth-client-credentials`, SEP-1046). - # - # The JWS is assembled with openssl so the SDK stays free of a JWT gem dependency - # (the TypeScript and Python SDKs use jose and PyJWT for the same assertion). - # Claims follow SEP-1046 and RFC 7523: `iss` and `sub` carry the client_id, - # `aud` carries the authorization server's issuer identifier, plus `exp`, `iat`, - # and a unique `jti`. - # - # - https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1046 - # - https://www.rfc-editor.org/rfc/rfc7523#section-2.2 - module JWTClientAssertion - # Raised when `signing_algorithm` is not supported. - class UnsupportedAlgorithmError < ArgumentError; end - - # Raised when the private key cannot be parsed or does not match - # the requested signing algorithm (e.g. an RSA key with ES256). - class InvalidKeyError < ArgumentError; end - - # RFC 7523 Section 2.2 `client_assertion_type` value. - ASSERTION_TYPE = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer" - - # Assertion lifetime in seconds; matches the TypeScript SDK's `jwtLifetimeSeconds` - # and the Python SDK's `lifetime_seconds` default. - DEFAULT_LIFETIME = 300 - - # ES256 produces a raw `r || s` JWS signature of two 32-byte integers. - ES256_COMPONENT_BYTES = 32 - private_constant :ES256_COMPONENT_BYTES - - SUPPORTED_ALGORITHMS = ["ES256", "RS256"].freeze - - class << self - # Returns a signed compact-serialization JWT (`header.payload.signature`). - # - # @param client_id [String] The pre-registered OAuth client identifier. - # @param audience [String] The authorization server's issuer identifier. - # @param private_key [String, OpenSSL::PKey::PKey] PEM string (PKCS#8 or - # traditional encoding) or an already-parsed key. - # @param signing_algorithm [String] `"ES256"` (prime256v1 EC key) or - # `"RS256"` (RSA key). - # @param lifetime [Integer] Seconds until the `exp` claim expires. - def generate(client_id:, audience:, private_key:, signing_algorithm:, lifetime: DEFAULT_LIFETIME) - unless SUPPORTED_ALGORITHMS.include?(signing_algorithm) - raise UnsupportedAlgorithmError, - "signing_algorithm must be one of #{SUPPORTED_ALGORITHMS.inspect} (got #{signing_algorithm.inspect})." - end - - key = parse_key(private_key) - validate_key!(key, signing_algorithm) - - now = Time.now.to_i - header = { alg: signing_algorithm, typ: "JWT" } - claims = { - iss: client_id, - sub: client_id, - aud: audience, - exp: now + lifetime, - iat: now, - jti: SecureRandom.uuid, - } - - signing_input = "#{base64url(JSON.generate(header))}.#{base64url(JSON.generate(claims))}" - "#{signing_input}.#{base64url(sign(key, signing_algorithm, signing_input))}" - end - - private - - def parse_key(private_key) - return private_key if private_key.is_a?(OpenSSL::PKey::PKey) - - OpenSSL::PKey.read(private_key.to_s) - rescue OpenSSL::PKey::PKeyError => e - raise InvalidKeyError, "private_key could not be parsed as a PEM-encoded key: #{e.message}." - end - - def validate_key!(key, signing_algorithm) - case signing_algorithm - when "ES256" - unless key.is_a?(OpenSSL::PKey::EC) && key.group.curve_name == "prime256v1" - raise InvalidKeyError, "ES256 requires an EC private key on the prime256v1 (P-256) curve." - end - when "RS256" - unless key.is_a?(OpenSSL::PKey::RSA) - raise InvalidKeyError, "RS256 requires an RSA private key." - end - end - - return if key.private? - - raise InvalidKeyError, "private_key must contain the private component to sign assertions." - end - - def sign(key, signing_algorithm, signing_input) - der = key.sign(OpenSSL::Digest.new("SHA256"), signing_input) - return der unless signing_algorithm == "ES256" - - ecdsa_der_to_raw(der) - end - - # `OpenSSL::PKey::EC#sign` returns an ASN.1 DER `SEQUENCE { r, s }`, - # while JWS ES256 (RFC 7518 Section 3.4) requires the raw 64-byte - # `r || s` concatenation with each integer left-padded to 32 bytes. - def ecdsa_der_to_raw(der) - OpenSSL::ASN1.decode(der).value.map do |integer| - integer.value.to_s(16).rjust(ES256_COMPONENT_BYTES * 2, "0") - end.join.then { |hex| [hex].pack("H*") } - end - - def base64url(data) - Base64.urlsafe_encode64(data, padding: false) - end - end - end - end - end -end diff --git a/lib/mcp/client/oauth/pkce.rb b/lib/mcp/client/oauth/pkce.rb deleted file mode 100644 index 63df4ff..0000000 --- a/lib/mcp/client/oauth/pkce.rb +++ /dev/null @@ -1,38 +0,0 @@ -# frozen_string_literal: true - -require "base64" -require "digest" -require "securerandom" - -module MCP - class Client - module OAuth - # Generates the Proof Key for Code Exchange (PKCE) pair (RFC 7636) used to - # bind an OAuth 2.1 authorization request to the same client that later - # redeems the resulting authorization code. Without PKCE, an attacker - # who steals an authorization code in transit (e.g. through a logged redirect URI) - # can exchange it for an access token; with PKCE, the attacker would also need - # the per-request `code_verifier`, which is never sent to the browser or any intermediary. - # - # MCP authorization mandates the `S256` method, so this module always returns - # that method and refuses to expose `plain` as an option. - # - # The module is stateless: callers ask for a fresh pair with `generate` for - # every authorization request and discard the result once the token endpoint has accepted it. - # - # - https://datatracker.ietf.org/doc/html/rfc7636 - # - https://modelcontextprotocol.io/specification/2025-11-25/basic/authorization#authorization-code-protection - module PKCE - class << self - # Generates a PKCE pair (code_verifier and S256 code_challenge). - def generate - verifier = SecureRandom.urlsafe_base64(64) - challenge = Base64.urlsafe_encode64(Digest::SHA256.digest(verifier), padding: false) - - { code_verifier: verifier, code_challenge: challenge, code_challenge_method: "S256" } - end - end - end - end - end -end diff --git a/lib/mcp/client/oauth/provider.rb b/lib/mcp/client/oauth/provider.rb deleted file mode 100644 index 803b5b9..0000000 --- a/lib/mcp/client/oauth/provider.rb +++ /dev/null @@ -1,144 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # Pluggable OAuth client configuration for the OAuth 2.1 Authorization Code + PKCE flow, - # handed to `MCP::Client::HTTP` via the `oauth:` keyword. - # Inspired by the OAuthClientProvider in the TypeScript SDK and the httpx.Auth-based provider - # in the Python SDK. For the non-interactive machine-to-machine `client_credentials` grant, - # use `ClientCredentialsProvider` instead. - # - # Required keyword arguments: - # - `client_metadata` - Hash sent to the authorization server's Dynamic Client - # Registration endpoint. Must include at minimum `redirect_uris`, - # `grant_types`, `response_types`, and `token_endpoint_auth_method`. - # When `application_type` is omitted, the SDK infers `"native"` or `"web"` - # from `redirect_uris` per SEP-837 before registering; an explicit value - # always wins. - # - `redirect_uri` - String: the redirect URI used for the authorization - # request. Must be one of `redirect_uris` in `client_metadata`. - # - `redirect_handler` - Callable invoked with the fully-built authorization - # URL (a `URI`). Implementations typically open the user's browser. - # - `callback_handler` - Callable invoked after `redirect_handler`. Returns - # `[code, state]` or `[code, state, iss]`, where `code` is the authorization code, - # `state` is the `state` parameter received on the redirect URI, and `iss` is - # the RFC 9207 `iss` parameter (or nil when the authorization response carried none). - # Returning the 3-element form opts into SEP-2468 issuer validation: a present `iss` - # must match the authorization server's issuer, and a nil `iss` is - # rejected when the AS advertises `authorization_response_iss_parameter_supported`. - # The 2-element form skips the check for backward compatibility. - # - # Optional keyword arguments: - # - `scope` - String of space-separated scopes to request when the server's - # `WWW-Authenticate` does not specify one. - # - `storage` - Object responding to `tokens`, `save_tokens(tokens)`, - # `client_information`, and `save_client_information(info)`. Defaults to - # an `InMemoryStorage`. Persisted `client_information` is stamped with - # an `"issuer"` member binding it to the authorization server that - # issued it (SEP-2352); when the authorization server changes, the SDK discards - # the stale registration and tokens and re-registers. - # - `client_id_metadata_document_url` - URL where the client publishes its Client ID Metadata Document - # (`draft-ietf-oauth-client-id-metadata-document-00` and the MCP authorization specification). - # When the authorization server advertises `client_id_metadata_document_supported: true`, - # the SDK uses this URL as the OAuth `client_id` and skips Dynamic Client Registration. - # Spec-required: `https://` scheme, a non-root path, and no fragment, userinfo, or `.`/`..` segments. - # The SDK additionally refuses to send query strings (the draft marks them only SHOULD NOT include, - # but different encodings of the same query would yield different `client_id` strings for the same document). - # The document served at the URL is a separate JSON artifact from the `client_metadata` keyword: - # DCR `client_metadata` MUST NOT include `client_id`, while the CIMD document MUST include `client_id` set - # to the URL, `client_name`, and `redirect_uris` covering `redirect_uri`. - # - `token_request_params` - Hash of String keys and values added to every token request this provider makes - # (the authorization code exchange and refresh), for parameters the authorization server requires beyond - # the grant itself. The authorization request is not affected. A key in `Flow::RESERVED_TOKEN_REQUEST_PARAMS` - # raises `Flow::InvalidTokenRequestParamsError`. - # The Hash is copied and frozen. See `StorageBackedProvider#token_request_params`. - # - `http_client_customizer` - Callable invoked with the `Faraday::Connection` the flow builds for - # its own requests; see `StorageBackedProvider#http_client_customizer`. - class Provider - include StorageBackedProvider - - # Raised when `Provider#initialize` is called with a `redirect_uri` that - # is neither HTTPS nor a loopback `http://` URL, per the MCP - # authorization spec's Communication Security requirement. - class InsecureRedirectURIError < ArgumentError; end - - # Raised when the `redirect_uri` argument is not listed in - # `client_metadata[:redirect_uris]` / `["redirect_uris"]`. Registering - # the URI with the authorization server but then sending a different - # one with the authorization request would be rejected by the AS at - # runtime; failing at construction surfaces the bug earlier. - class UnregisteredRedirectURIError < ArgumentError; end - - # Raised when `client_id_metadata_document_url` is provided but does not meet - # the structural requirements for a Client ID Metadata Document URL: - # HTTPS, non-root path, and no fragment, query, userinfo, or `.`/`..` segments. - # The CIMD URL is sent to the authorization server as the OAuth `client_id`, - # so the same Communication Security guarantee that protects the redirect URI - # applies and the value must unambiguously identify the document. - class InvalidClientIDMetadataDocumentURLError < ArgumentError; end - - attr_reader :client_metadata, - :redirect_uri, - :scope, - :storage, - :redirect_handler, - :callback_handler, - :client_id_metadata_document_url - - def initialize( - client_metadata:, - redirect_uri:, - redirect_handler:, - callback_handler:, - scope: nil, - storage: nil, - client_id_metadata_document_url: nil, - authorization_request_validator: nil, - token_request_params: nil, - http_client_customizer: nil - ) - unless Discovery.secure_url?(redirect_uri) - raise InsecureRedirectURIError, - "redirect_uri #{redirect_uri.inspect} must use https or be a loopback http URL " \ - "(localhost, 127.0.0.0/8, or ::1) per the MCP authorization Communication Security requirement." - end - - registered = Array(client_metadata[:redirect_uris] || client_metadata["redirect_uris"]) - unless registered.include?(redirect_uri) - raise UnregisteredRedirectURIError, - "redirect_uri #{redirect_uri.inspect} must be listed in client_metadata[:redirect_uris] " \ - "(got #{registered.inspect}); otherwise the authorization server will reject the authorization request." - end - - if client_id_metadata_document_url && !Discovery.client_id_metadata_document_url?(client_id_metadata_document_url) - raise InvalidClientIDMetadataDocumentURLError, - "client_id_metadata_document_url #{client_id_metadata_document_url.inspect} must be an https URL " \ - "with a non-root path and no fragment, query, userinfo, or `.`/`..` segments, " \ - "per the MCP authorization specification and `draft-ietf-oauth-client-id-metadata-document`." - end - - http_client_customizer = validated_http_client_customizer(http_client_customizer) - - @client_metadata = client_metadata - @redirect_uri = redirect_uri - @redirect_handler = redirect_handler - @callback_handler = callback_handler - @scope = scope - @storage = storage || InMemoryStorage.new - @client_id_metadata_document_url = client_id_metadata_document_url - @authorization_request_validator = authorization_request_validator - @token_request_params = frozen_token_request_params(token_request_params) - @http_client_customizer = http_client_customizer - end - - # Identifies the OAuth flow this provider drives. - # `Flow` dispatches on this rather than inspecting `client_metadata[:grant_types]`, - # which is protocol metadata for the authorization server, not an SDK control signal. - def authorization_flow - :authorization_code - end - end - end - end -end diff --git a/lib/mcp/client/oauth/storage_backed_provider.rb b/lib/mcp/client/oauth/storage_backed_provider.rb deleted file mode 100644 index 087f223..0000000 --- a/lib/mcp/client/oauth/storage_backed_provider.rb +++ /dev/null @@ -1,87 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - module OAuth - # Shared token/credential persistence for the OAuth provider classes - # (`Provider` for the authorization-code flow, `ClientCredentialsProvider` - # for the client_credentials flow, and `CrossAppAccessProvider` for the jwt-bearer flow). - # The grants differ in how they authenticate, but all read and write the same two pieces of state - # through a `storage` object: the token response and the client information. This module supplies - # that delegation so the `Flow` orchestrator can treat any provider uniformly. - # - # Including classes must set `@storage` to an object responding to `tokens`, - # `save_tokens(tokens)`, `client_information`, and `save_client_information(info)` - # (see `InMemoryStorage`). - module StorageBackedProvider - # Optional `->(request) { true | false }` hook, called with an `AuthorizationRequest`. - # An MCP server names its own authorization server and the scopes to ask for, so this is where - # an embedding application sees both before the request is made and can decline to proceed. - # `nil` (the default) authorizes whatever the server asked for, which is the behavior every - # MCP SDK has today. - attr_reader :authorization_request_validator - - # Optional Hash of String keys and values added to every token request the provider makes, for parameters - # the authorization server requires beyond the grant itself (RFC 6749 Section 8.2 leaves room for them; - # Auth0's `audience` is the usual one). `nil` (the default) adds nothing. - # Set through `frozen_token_request_params`, which refuses a key `Flow` sets itself or a wrongly shaped value - # with `Flow::InvalidTokenRequestParamsError`. - attr_reader :token_request_params - - # Optional callable invoked with the `Faraday::Connection` the flow builds for its own requests, - # after the SDK's defaults and before its origin guard (see `Flow.build_http_client`), so an application can - # add middleware to discovery, registration, and token requests or swap their adapter. `nil` (the default) - # keeps the default connection. The transport's own connection and customizer block never serve these requests: - # they are bound to the MCP server URL and carry headers meant for that server. - attr_reader :http_client_customizer - - def access_token - tokens&.dig("access_token") || tokens&.dig(:access_token) - end - - def tokens - @storage.tokens - end - - def save_tokens(tokens) - @storage.save_tokens(tokens) - end - - def client_information - @storage.client_information - end - - def save_client_information(info) - @storage.save_client_information(info) - end - - def clear_tokens! - @storage.save_tokens(nil) - end - - private - - # Constructors call this before writing to `storage`, so a rejected provider leaves it untouched. - # The copy has its own frozen keys and values, so a later change to the caller's Hash, to a key, - # or to a value cannot alter what is sent to the token endpoint. Keys are copied explicitly - # because `Hash` copies and freezes only keys whose class is exactly `String`. - def frozen_token_request_params(params) - return if params.nil? - - problem = Flow.token_request_params_problem(params) - raise Flow::InvalidTokenRequestParamsError, "token_request_params #{problem}" if problem - - params.each_with_object({}) { |(key, value), copy| copy[key.dup.freeze] = value.dup.freeze }.freeze - end - - # Returns `customizer` when it is `nil` or callable and raises otherwise, so a connection object passed - # in place of a callable fails at construction rather than at the first `401`. - def validated_http_client_customizer(customizer) - return customizer if customizer.nil? || customizer.respond_to?(:call) - - raise ArgumentError, "http_client_customizer must respond to call (got #{customizer.class})." - end - end - end - end -end diff --git a/lib/mcp/client/paginated_result.rb b/lib/mcp/client/paginated_result.rb deleted file mode 100644 index eb06ee6..0000000 --- a/lib/mcp/client/paginated_result.rb +++ /dev/null @@ -1,15 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Client - # Result objects returned by `list_tools`, `list_prompts`, `list_resources`, and `list_resource_templates`. - # Each carries the page items, an optional opaque `next_cursor` string for continuing pagination, - # an optional `meta` hash mirroring the MCP `_meta` response field, and the optional SEP-2549 - # cache hints `ttl_ms` (freshness lifetime in milliseconds; 0 means do not cache) and - # `cache_scope` (`"public"` or `"private"`) mirroring the `ttlMs`/`cacheScope` response fields. - ListToolsResult = Struct.new(:tools, :next_cursor, :meta, :ttl_ms, :cache_scope, keyword_init: true) - ListPromptsResult = Struct.new(:prompts, :next_cursor, :meta, :ttl_ms, :cache_scope, keyword_init: true) - ListResourcesResult = Struct.new(:resources, :next_cursor, :meta, :ttl_ms, :cache_scope, keyword_init: true) - ListResourceTemplatesResult = Struct.new(:resource_templates, :next_cursor, :meta, :ttl_ms, :cache_scope, keyword_init: true) - end -end diff --git a/lib/mcp/client/stdio.rb b/lib/mcp/client/stdio.rb deleted file mode 100644 index 0fbb96e..0000000 --- a/lib/mcp/client/stdio.rb +++ /dev/null @@ -1,537 +0,0 @@ -# frozen_string_literal: true - -require "json" -require "open3" -require "securerandom" -require "timeout" -require_relative "../../json_rpc_handler" -require_relative "../configuration" -require_relative "../methods" -require_relative "../protocol_deprecations" -require_relative "../version" -require_relative "modern_envelope" - -module MCP - class Client - class Stdio - # Seconds to wait for the server process to exit before sending SIGTERM. - # Matches the Python and TypeScript SDKs' shutdown timeout: - # https://github.com/modelcontextprotocol/python-sdk/blob/v1.26.0/src/mcp/client/stdio/__init__.py#L48 - # https://github.com/modelcontextprotocol/typescript-sdk/blob/v1.27.1/src/client/stdio.ts#L221 - CLOSE_TIMEOUT = 2 - STDERR_READ_SIZE = 4096 - - # Default upper bound on a single newline-delimited frame read from the - # server's stdout. CRuby's `IO#gets` without a limit accumulates bytes until a - # newline arrives, so a spawned server that never emits one can grow a single - # String until the host process is OOM-killed. 4 MiB is large enough for any - # realistic JSON-RPC frame, including base64-embedded images. - MAX_LINE_BYTES = 4 * 1024 * 1024 - - # Seconds the `server/discover` probe may wait when no `read_timeout` was configured. - # A compliant legacy server answers the probe with `-32601` immediately, but a non-compliant one - # that silently drops unknown methods would otherwise block `connect(mode: :auto)` forever. - # Matches the C# SDK's `DiscoverProbeTimeout` default. - DEFAULT_DISCOVER_PROBE_TIMEOUT = 5 - - attr_reader :command, :args, :env, :server_info - - def initialize(command:, args: [], env: nil, read_timeout: nil, max_line_bytes: MAX_LINE_BYTES) - # Reject `nil` or non-positive values: `IO#gets("\n", nil)` and a negative - # limit read without an upper bound, which would silently disable the - # protection this option exists to provide. - unless max_line_bytes.is_a?(Integer) && max_line_bytes > 0 - raise ArgumentError, "max_line_bytes must be a positive Integer" - end - - @command = command - @args = args - @env = env - @read_timeout = read_timeout - @max_line_bytes = max_line_bytes - @stdin = nil - @stdout = nil - @stderr = nil - @wait_thread = nil - @stderr_thread = nil - @started = false - @initialized = false - @server_info = nil - @modern_protocol_version = nil - @modern_client_info = nil - @modern_capabilities = nil - # Serializes writes to `@stdin` so a request line and a notification line emitted from - # different threads (e.g. cancellation) cannot interleave on the wire. - @write_mutex = Mutex.new - end - - # Performs the MCP `initialize` handshake: sends an `initialize` request - # followed by the required `notifications/initialized` notification. The - # server's `InitializeResult` (protocol version, capabilities, server - # info, instructions) is cached on the transport and returned. - # - # Idempotent: a second call returns the cached `InitializeResult` without - # contacting the server. After `close`, state is cleared and `connect` - # will handshake again. Spawns the subprocess via `start` if it has not - # been started yet. - # - # @param client_info [Hash, nil] `{ name:, version: }` identifying the client. - # Defaults to `{ name: "mcp-ruby-client", version: MCP::VERSION }`. - # @param protocol_version [String, nil] Protocol version to offer on the legacy handshake. - # Defaults to `MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION`; a modern version - # raises `ArgumentError` here (modern versions are selected via `mode: :modern`/`:auto`). - # @param capabilities [Hash] Capabilities advertised by the client. Defaults to `{}`. - # @return [Hash] The server's `InitializeResult`. - # @raise [RequestHandlerError] If the server responds with a JSON-RPC error, - # a malformed result, or an unsupported protocol version. - # @param mode [Symbol] Lifecycle selection (SEP-2575): `:legacy` (default) performs - # the handshake below, `:modern` skips it and probes `server/discover`, - # and `:auto` probes `server/discover` first, falling back to the legacy handshake - # when the server does not serve a mutually supported modern version. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#initialization - def connect(client_info: nil, protocol_version: nil, capabilities: {}, mode: :legacy) - return @server_info if connected? - - # Validated before `start` so a pure argument error never spawns the server process. - MCP::Configuration.reject_modern_handshake_version!(protocol_version) if mode == :legacy - - start unless @started - - client_info ||= { name: "mcp-ruby-client", version: MCP::VERSION } - - case mode - when :legacy - connect_legacy(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - when :modern - connect_modern(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - when :auto - connect_auto(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - else - raise ArgumentError, "mode must be :legacy, :modern, or :auto" - end - end - - # Whether the transport operates in the stateless modern lifecycle (SEP-2575): - # no handshake was performed and every request carries the `_meta` envelope. - def modern? - !@modern_client_info.nil? - end - - # The protocol version in use on this connection, independent of its era: - # negotiated by `initialize` (legacy) or adopted via `server/discover` (modern). - # Returns `nil` before `connect` and after `close`. - def protocol_version - @modern_protocol_version || (@server_info && @server_info["protocolVersion"]) - end - - # Returns true once `connect` has completed the handshake or adopted the modern lifecycle. - # Returns false before the handshake and after `close`. - def connected? - @initialized || modern? - end - - # Transports may yield once the request line has been written to `@stdin`. - # `MCP::Client#dispatch_with_cancellation` uses this signal to ensure a `notifications/cancelled` - # write does not race ahead of the request write on the wire. The yield happens inside `@write_mutex`, - # so any subsequent `send_notification` write waits for the mutex and is guaranteed to land after the request. - def send_request(request:) - method = request[:method] || request["method"] - if method == MCP::Methods::SERVER_DISCOVER - # `server/discover` (SEP-2575) is sessionless capability discovery that - # works before (or instead of) `connect`. - start unless @started - elsif !connected? - raise "MCP::Client#connect must be called before sending requests." - end - - request = stamp_modern(request) - - @write_mutex.synchronize do - write_message(request) - yield if block_given? - end - read_response(request) - end - - # Sends a JSON-RPC notification (no response expected). Used by `Client#cancel` to deliver - # `notifications/cancelled` for an in-flight request. - def send_notification(notification:) - start unless @started - connect unless connected? - - @write_mutex.synchronize { write_message(notification) } - nil - end - - def start - raise "MCP::Client::Stdio already started" if @started - - spawn_env = @env || {} - @stdin, @stdout, @stderr, @wait_thread = Open3.popen3(spawn_env, @command, *@args) - @stdout.set_encoding("UTF-8") - @stdin.set_encoding("UTF-8") - - # Drain stderr in the background to prevent the pipe buffer from filling up, - # which would cause the server process to block and deadlock. - @stderr_thread = Thread.new do - loop do - @stderr.readpartial(STDERR_READ_SIZE) - end - rescue IOError - nil - end - - @started = true - rescue Errno::ENOENT, Errno::EACCES, Errno::ENOEXEC => e - raise RequestHandlerError.new( - "Failed to spawn server process: #{e.message}", - {}, - error_type: :internal_error, - original_error: e, - ) - end - - def close - return unless @started - - @stdin.close - @stdout.close - @stderr.close - - begin - Timeout.timeout(CLOSE_TIMEOUT) { @wait_thread.value } - rescue Timeout::Error - begin - Process.kill("TERM", @wait_thread.pid) - Timeout.timeout(CLOSE_TIMEOUT) { @wait_thread.value } - rescue Timeout::Error - begin - Process.kill("KILL", @wait_thread.pid) - rescue Errno::ESRCH - nil - end - rescue Errno::ESRCH - nil - end - end - - @stderr_thread.join(CLOSE_TIMEOUT) - @started = false - @initialized = false - @server_info = nil - leave_modern_mode - end - - private - - def connect_legacy(client_info:, protocol_version:, capabilities:) - protocol_version ||= MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION - - init_request = { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: SecureRandom.uuid, - method: MCP::Methods::INITIALIZE, - params: { - protocolVersion: protocol_version, - capabilities: capabilities, - clientInfo: client_info, - }, - } - - write_message(init_request) - response = read_response(init_request) - - if response.key?("error") - error = response["error"] - raise RequestHandlerError.new( - "Server initialization failed: #{error["message"]}", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - unless response["result"].is_a?(Hash) - raise RequestHandlerError.new( - "Server initialization failed: missing result in response", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - @server_info = response["result"] - - negotiated_protocol_version = @server_info["protocolVersion"] - unless MCP::Configuration::SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS.include?(negotiated_protocol_version) - # Per spec, if the client does not support the server's returned protocol version, - # the client SHOULD disconnect. A modern version is rejected along with unknown ones: - # the handshake settles on a legacy version by definition, and the TypeScript and Python clients refuse - # a modern counter-offer the same way. Roll back the cached `InitializeResult` before raising - # so a retry starts without a stale `server_info`. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#version-negotiation - @server_info = nil - raise RequestHandlerError.new( - "Server initialization failed: unsupported protocol version #{negotiated_protocol_version.inspect}", - { method: MCP::Methods::INITIALIZE }, - error_type: :internal_error, - ) - end - - begin - notification = { - jsonrpc: JsonRpcHandler::Version::V2_0, - method: MCP::Methods::NOTIFICATIONS_INITIALIZED, - } - write_message(notification) - rescue StandardError - @server_info = nil - raise - end - - @initialized = true - @server_info - end - - # Enters the modern lifecycle by probing `server/discover` at the requested (or latest) modern version. - # No `initialize` or `notifications/initialized` is sent; the probe response becomes `server_info`. - def connect_modern(client_info:, protocol_version:, capabilities:) - version = protocol_version || MCP::Configuration::LATEST_MODERN_PROTOCOL_VERSION - unless MCP::Configuration.modern_protocol_version?(version) - raise ArgumentError, "protocol_version #{version.inspect} is not a supported modern protocol version" - end - - @modern_protocol_version = version - @modern_client_info = client_info - @modern_capabilities = capabilities || {} - - begin - result = with_probe_read_timeout { probe_discover } - rescue StandardError - leave_modern_mode - raise - end - - supported = result["supportedVersions"] - unless supported.is_a?(Array) && supported.include?(version) - leave_modern_mode - raise RequestHandlerError.new( - "Server discovery failed: no mutually supported modern protocol version " \ - "(server supports #{supported.inspect})", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - # SEP-2577 deprecates roots and sampling at 2026-07-28, the revision every modern connection speaks, - # so the warning lives here now that the handshake cannot land on one. - MCP::ProtocolDeprecations.warn_for_client_capabilities(capabilities, protocol_version: version, uplevel: 1) - - @server_info = result - @server_info - end - - # Probes `server/discover` and adopts the modern lifecycle when the server serves - # a mutually supported modern version; otherwise falls back to the legacy handshake. - # The fallback intentionally covers a successful discovery without a mutual modern - # version as well: during the 2026-07-28 rollout a server may answer discovery while - # only serving legacy versions. - def connect_auto(client_info:, protocol_version:, capabilities:) - modern_pin = protocol_version if protocol_version && MCP::Configuration.modern_protocol_version?(protocol_version) - connect_modern(client_info: client_info, protocol_version: modern_pin, capabilities: capabilities) - rescue RequestHandlerError - # An explicitly requested modern version is never downgraded by the fallback: the legacy handshake cannot negotiate it, - # so the probe's failure is the real answer and propagates. - raise if modern_pin - - connect_legacy(client_info: client_info, protocol_version: protocol_version, capabilities: capabilities) - end - - def leave_modern_mode - @modern_protocol_version = nil - @modern_client_info = nil - @modern_capabilities = nil - end - - # Bounds the probe read when the caller configured no `read_timeout`, and only for the probe: - # regular requests keep the unbounded default so long-running tools are unaffected. - # The timeout surfaces as a `RequestHandlerError`, which `connect_auto` treats as legacy evidence - # and falls back on. - def with_probe_read_timeout - return yield if @read_timeout - - @read_timeout = DEFAULT_DISCOVER_PROBE_TIMEOUT - begin - yield - ensure - @read_timeout = nil - end - end - - def probe_discover - request = { - jsonrpc: JsonRpcHandler::Version::V2_0, - id: SecureRandom.uuid, - method: MCP::Methods::SERVER_DISCOVER, - } - - @write_mutex.synchronize { write_message(stamp_modern(request)) } - response = read_response(request) - - if response.key?("error") - error = response["error"] - raise RequestHandlerError.new( - "Server discovery failed: #{error["message"]}", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - result = response["result"] - unless result.is_a?(Hash) - raise RequestHandlerError.new( - "Server discovery failed: missing result in response", - { method: MCP::Methods::SERVER_DISCOVER }, - error_type: :internal_error, - ) - end - - result - end - - # Modern requests (never notifications, whose `_meta` has no envelope) carry the SEP-2575 triple. - def stamp_modern(request) - return request unless modern? && (request[:id] || request["id"]) - - ModernEnvelope.stamp( - request, - protocol_version: @modern_protocol_version, - client_info: @modern_client_info, - capabilities: @modern_capabilities, - ) - end - - def write_message(message) - ensure_running! - json = JSON.generate(message) - @stdin.puts(json) - @stdin.flush - rescue IOError, Errno::EPIPE => e - raise RequestHandlerError.new( - "Failed to write to server process", - {}, - error_type: :internal_error, - original_error: e, - ) - end - - def read_response(request) - request_id = request[:id] || request["id"] - method = request[:method] || request["method"] - params = request[:params] || request["params"] - - loop do - ensure_running! - wait_for_readable!(method, params) if @read_timeout - line = read_line(method, params) - raise_connection_error!(method, params) if line.nil? - - parsed = JSON.parse(line.strip) - - # A frame carrying `method` is a request or notification, never the awaited response, - # whatever its id says: JSON-RPC id spaces are per sender, so a server-chosen ping id - # may legitimately collide with the awaited one. Pings are answered; - # other server-to-client requests over stdio stay unsupported as documented, - # and notifications carry no id. - if parsed.is_a?(Hash) && parsed.key?("method") - # A JSON-RPC id is a String or a Number; the reference SDKs reject other shapes at - # schema validation, so a ping carrying one is skipped rather than echoed back. - answer_ping(parsed) if parsed["method"] == MCP::Methods::PING && json_rpc_id?(parsed["id"]) - next - end - - # A JSON-RPC message is an object; skip a non-object frame (array or scalar) - # the same way as a frame without an id. - next unless parsed.is_a?(Hash) && parsed.key?("id") - - return parsed if parsed["id"] == request_id - end - rescue JSON::ParserError => e - raise RequestHandlerError.new( - "Failed to parse server response", - { method: method, params: params }, - error_type: :internal_error, - original_error: e, - ) - end - - # The ping receiver "MUST respond promptly with an empty response". Answered inline from - # the read loop, so a keepalive cannot stall unanswered while a response is awaited; - # between requests nothing reads stdout, and a queued ping is answered on the next read. - def answer_ping(parsed) - @write_mutex.synchronize do - write_message({ jsonrpc: JsonRpcHandler::Version::V2_0, id: parsed["id"], result: {} }) - end - rescue RequestHandlerError - # Best effort: a pong cannot be delivered over a broken stdin, and the failure must not - # surface as an error of the unrelated request whose response the loop is reading. - end - - def json_rpc_id?(id) - id.is_a?(String) || id.is_a?(Numeric) - end - - def ensure_running! - return if @wait_thread.alive? - - raise RequestHandlerError.new( - "Server process has exited", - {}, - error_type: :internal_error, - ) - end - - def wait_for_readable!(method, params) - ready = @stdout.wait_readable(@read_timeout) - return if ready - - raise RequestHandlerError.new( - "Timed out waiting for server response", - { method: method, params: params }, - error_type: :internal_error, - ) - end - - # Reads one newline-delimited frame from the server's stdout, bounded by `@max_line_bytes`. - # Returns the line (including its trailing newline) or `nil` at EOF. Raises when the limit - # is reached before a newline arrives, which signals a server streaming an unbounded frame. - # A short final frame without a trailing newline (EOF) is still returned, since its length - # stays under the limit. - def read_line(method, params) - line = @stdout.gets("\n", @max_line_bytes) - return line unless line && !line.end_with?("\n") && line.bytesize >= @max_line_bytes - - # The over-limit frame leaves leftover bytes in the pipe, so the stream is desynced and - # cannot be resumed. Close before raising so a later `send_request` fails cleanly instead - # of parsing a truncated frame. - begin - close - rescue StandardError - nil - end - - raise RequestHandlerError.new( - "Server response frame exceeds #{@max_line_bytes} bytes without a newline", - { method: method, params: params }, - error_type: :internal_error, - ) - end - - def raise_connection_error!(method, params) - raise RequestHandlerError.new( - "Server process closed stdout unexpectedly", - { method: method, params: params }, - error_type: :internal_error, - ) - end - end - end -end diff --git a/lib/mcp/client/tool.rb b/lib/mcp/client/tool.rb index bfefda8..b348d4d 100644 --- a/lib/mcp/client/tool.rb +++ b/lib/mcp/client/tool.rb @@ -3,14 +3,13 @@ module MCP class Client class Tool - attr_reader :name, :description, :input_schema, :output_schema, :annotations + attr_reader :name, :description, :input_schema, :output_schema - def initialize(name:, description:, input_schema:, output_schema: nil, annotations: nil) + def initialize(name:, description:, input_schema:, output_schema: nil) @name = name @description = description @input_schema = input_schema @output_schema = output_schema - @annotations = annotations end end end diff --git a/lib/mcp/configuration.rb b/lib/mcp/configuration.rb index 4d4b78e..03105bd 100644 --- a/lib/mcp/configuration.rb +++ b/lib/mcp/configuration.rb @@ -2,73 +2,24 @@ module MCP class Configuration - LATEST_STABLE_PROTOCOL_VERSION = "2026-07-28" - ROOTS_SAMPLING_LOGGING_DEPRECATED_PROTOCOL_VERSION = "2026-07-28" + LATEST_STABLE_PROTOCOL_VERSION = "2025-11-25" SUPPORTED_STABLE_PROTOCOL_VERSIONS = [ - LATEST_STABLE_PROTOCOL_VERSION, "2025-11-25", "2025-06-18", "2025-03-26", "2024-11-05", - ].freeze - DEFAULT_NEGOTIATED_PROTOCOL_VERSION = "2025-03-26" + LATEST_STABLE_PROTOCOL_VERSION, "2025-06-18", "2025-03-26", "2024-11-05", + ] - # Protocol versions of the stateless "modern" lifecycle introduced by the MCP 2026-07-28 spec release (SEP-2575), - # where each request carries its own version in `_meta` and is validated against this list independently, - # with no handshake. These are reachable only through `server/discover` and the per-request envelope. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - LATEST_MODERN_PROTOCOL_VERSION = "2026-07-28" - SUPPORTED_MODERN_PROTOCOL_VERSIONS = [LATEST_MODERN_PROTOCOL_VERSION].freeze + attr_writer :exception_reporter, :instrumentation_callback - # Protocol versions reachable through the legacy `initialize` handshake, derived so the era partition - # (handshake = stable minus modern) cannot drift when a new revision lands. - # Per the SEP-2575 era model, an era is a property of the protocol version itself: legacy versions establish - # a session via `initialize` (2025-11-25 and earlier), and modern versions carry the version on every request - # in `_meta` with no handshake at all. The handshake therefore never negotiates a modern version: - # a client asking `initialize` for one is counter-offered - # `LATEST_HANDSHAKE_PROTOCOL_VERSION`, matching the TypeScript and Python SDKs. - SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS = (SUPPORTED_STABLE_PROTOCOL_VERSIONS - SUPPORTED_MODERN_PROTOCOL_VERSIONS).freeze - LATEST_HANDSHAKE_PROTOCOL_VERSION = SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS.first - - class << self - def modern_protocol_version?(version) - SUPPORTED_MODERN_PROTOCOL_VERSIONS.include?(version) - end - - def handshake_protocol_version?(version) - SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS.include?(version) - end - - # The one statement of the client-side handshake contract, shared by every transport: - # a modern version cannot ride the legacy `initialize` handshake. - def reject_modern_handshake_version!(version) - return unless version && modern_protocol_version?(version) - - raise ArgumentError, "protocol version #{version.inspect} cannot be negotiated through the legacy " \ - "`initialize` handshake; use `mode: :modern` (or `:auto`) instead" - end - end - - attr_writer :exception_reporter, :around_request - - # @deprecated Use {#around_request=} instead. `instrumentation_callback` - # fires only after a request completes and cannot wrap execution in a - # surrounding block (e.g. for Application Performance Monitoring (APM) spans). - # @see #around_request= - attr_writer :instrumentation_callback - - def initialize(exception_reporter: nil, around_request: nil, instrumentation_callback: nil, protocol_version: nil, - validate_tool_call_arguments: true, validate_tool_call_results: false, instrument_server_context: false) + def initialize(exception_reporter: nil, instrumentation_callback: nil, protocol_version: nil, + validate_tool_call_arguments: true) @exception_reporter = exception_reporter - @around_request = around_request @instrumentation_callback = instrumentation_callback @protocol_version = protocol_version if protocol_version validate_protocol_version!(protocol_version) end validate_value_of_validate_tool_call_arguments!(validate_tool_call_arguments) - validate_value_of_validate_tool_call_results!(validate_tool_call_results) - validate_value_of_instrument_server_context!(instrument_server_context) @validate_tool_call_arguments = validate_tool_call_arguments - @validate_tool_call_results = validate_tool_call_results - @instrument_server_context = instrument_server_context end def protocol_version=(protocol_version) @@ -83,28 +34,8 @@ module MCP @validate_tool_call_arguments = validate_tool_call_arguments end - # Opt in to exposing the user-defined `server_context` in the - # `around_request` / `instrumentation_callback` data hash. Off by default: - # the hash is application-supplied and may hold values a tracing backend - # should not receive, so surfacing it has to be a deliberate choice. - def instrument_server_context=(instrument_server_context) - validate_value_of_instrument_server_context!(instrument_server_context) - - @instrument_server_context = instrument_server_context - end - - def validate_tool_call_results=(validate_tool_call_results) - validate_value_of_validate_tool_call_results!(validate_tool_call_results) - - @validate_tool_call_results = validate_tool_call_results - end - - # The pin scopes the `initialize` handshake, so an unset pin reads as the version that handshake - # settles on by default. Reading the newest version of any era here would hand back a value - # the writer rejects, and no caller wants the modern revision: a modern connection carries - # its version on every request instead of consulting configuration. def protocol_version - @protocol_version || LATEST_HANDSHAKE_PROTOCOL_VERSION + @protocol_version || LATEST_STABLE_PROTOCOL_VERSION end def protocol_version? @@ -119,43 +50,20 @@ module MCP !@exception_reporter.nil? end - def around_request - @around_request || default_around_request - end - - def around_request? - !@around_request.nil? - end - - # @deprecated Use {#around_request} instead. `instrumentation_callback` - # fires only after a request completes and cannot wrap execution in a - # surrounding block (e.g. for Application Performance Monitoring (APM) spans). - # @see #around_request def instrumentation_callback @instrumentation_callback || default_instrumentation_callback end - # @deprecated Use {#around_request?} instead. - # @see #around_request? def instrumentation_callback? !@instrumentation_callback.nil? end attr_reader :validate_tool_call_arguments - attr_reader :validate_tool_call_results - - def instrument_server_context? - !!@instrument_server_context - end def validate_tool_call_arguments? !!@validate_tool_call_arguments end - def validate_tool_call_results? - !!@validate_tool_call_results - end - def merge(other) return self if other.nil? @@ -164,59 +72,33 @@ module MCP else @exception_reporter end - - around_request = if other.around_request? - other.around_request - else - @around_request - end - instrumentation_callback = if other.instrumentation_callback? other.instrumentation_callback else @instrumentation_callback end - protocol_version = if other.protocol_version? other.protocol_version else @protocol_version end - validate_tool_call_arguments = other.validate_tool_call_arguments - validate_tool_call_results = other.validate_tool_call_results Configuration.new( exception_reporter: exception_reporter, - around_request: around_request, instrumentation_callback: instrumentation_callback, protocol_version: protocol_version, validate_tool_call_arguments: validate_tool_call_arguments, - validate_tool_call_results: validate_tool_call_results, - instrument_server_context: other.instrument_server_context?, ) end private - # A pin scopes the `initialize` handshake, so only handshake versions are accepted: - # a modern version has no handshake to pin (its version rides every request in `_meta`), - # and accepting one here would configure nothing. Failing at construction beats - # a setting that silently does not apply. def validate_protocol_version!(protocol_version) - return if SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS.include?(protocol_version) - - # A version this SDK serves, rejected only for where it was set, deserves the reason and - # the alternative rather than a list it is missing from: this is the error an upgrade from - # a release that accepted the value lands on, so it doubles as the migration note. - if self.class.modern_protocol_version?(protocol_version) - raise ArgumentError, "protocol_version #{protocol_version.inspect} is a modern protocol version and cannot be pinned here: " \ - "the pin scopes the `initialize` handshake, which never negotiates a modern version. " \ - "Modern clients carry their version on every request and need no pin; remove the setting." + unless SUPPORTED_STABLE_PROTOCOL_VERSIONS.include?(protocol_version) + message = "protocol_version must be #{SUPPORTED_STABLE_PROTOCOL_VERSIONS[0...-1].join(", ")}, or #{SUPPORTED_STABLE_PROTOCOL_VERSIONS[-1]}" + raise ArgumentError, message end - - raise ArgumentError, "protocol_version must be #{SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS[0...-1].join(", ")}, " \ - "or #{SUPPORTED_HANDSHAKE_PROTOCOL_VERSIONS[-1]}" end def validate_value_of_validate_tool_call_arguments!(validate_tool_call_arguments) @@ -225,27 +107,10 @@ module MCP end end - def validate_value_of_validate_tool_call_results!(validate_tool_call_results) - unless validate_tool_call_results.is_a?(TrueClass) || validate_tool_call_results.is_a?(FalseClass) - raise ArgumentError, "validate_tool_call_results must be a boolean" - end - end - - def validate_value_of_instrument_server_context!(instrument_server_context) - unless instrument_server_context.is_a?(TrueClass) || instrument_server_context.is_a?(FalseClass) - raise ArgumentError, "instrument_server_context must be a boolean" - end - end - def default_exception_reporter @default_exception_reporter ||= ->(exception, server_context) {} end - def default_around_request - @default_around_request ||= ->(_data, &request_handler) { request_handler.call } - end - - # @deprecated Use {#default_around_request} instead. def default_instrumentation_callback @default_instrumentation_callback ||= ->(data) {} end diff --git a/lib/mcp/content.rb b/lib/mcp/content.rb index 591ecb4..7ab984d 100644 --- a/lib/mcp/content.rb +++ b/lib/mcp/content.rb @@ -3,60 +3,29 @@ module MCP module Content class Text - attr_reader :text, :annotations, :meta + attr_reader :text, :annotations - def initialize(text, annotations: nil, meta: nil) + def initialize(text, annotations: nil) @text = text @annotations = annotations - @meta = meta end def to_h - { text: text, annotations: annotations, _meta: meta, type: "text" }.compact + { text: text, annotations: annotations, type: "text" }.compact end end class Image - attr_reader :data, :mime_type, :annotations, :meta + attr_reader :data, :mime_type, :annotations - def initialize(data, mime_type, annotations: nil, meta: nil) + def initialize(data, mime_type, annotations: nil) @data = data @mime_type = mime_type @annotations = annotations - @meta = meta end def to_h - { data: data, mimeType: mime_type, annotations: annotations, _meta: meta, type: "image" }.compact - end - end - - class Audio - attr_reader :data, :mime_type, :annotations, :meta - - def initialize(data, mime_type, annotations: nil, meta: nil) - @data = data - @mime_type = mime_type - @annotations = annotations - @meta = meta - end - - def to_h - { data: data, mimeType: mime_type, annotations: annotations, _meta: meta, type: "audio" }.compact - end - end - - class EmbeddedResource - attr_reader :resource, :annotations, :meta - - def initialize(resource, annotations: nil, meta: nil) - @resource = resource - @annotations = annotations - @meta = meta - end - - def to_h - { resource: resource.to_h, annotations: annotations, _meta: meta, type: "resource" }.compact + { data: data, mime_type: mime_type, annotations: annotations, type: "image" }.compact end end end diff --git a/lib/mcp/elicitation.rb b/lib/mcp/elicitation.rb deleted file mode 100644 index 26186c7..0000000 --- a/lib/mcp/elicitation.rb +++ /dev/null @@ -1,10 +0,0 @@ -# frozen_string_literal: true - -module MCP - # Builders for elicitation `requestedSchema` definitions per MCP 2025-11-25. - # Each builder returns an instance whose `to_h` produces the JSON-Schema-shaped Hash - # a server passes as a property value in `create_form_elicitation(requested_schema:)`. - module Elicitation - autoload :EnumSchema, "mcp/elicitation/enum_schema" - end -end diff --git a/lib/mcp/elicitation/enum_schema.rb b/lib/mcp/elicitation/enum_schema.rb deleted file mode 100644 index 191a20f..0000000 --- a/lib/mcp/elicitation/enum_schema.rb +++ /dev/null @@ -1,121 +0,0 @@ -# frozen_string_literal: true - -module MCP - module Elicitation - # Builds the four enum schema variants defined by MCP 2025-11-25 (SEP-1330) plus the legacy `enumNames` form - # retained for backward compatibility. - # - # Each class method returns an `EnumSchema` instance; call `to_h` to get the property-value Hash and - # pass it through `requested_schema` to `ServerSession#create_form_elicitation`. - class EnumSchema - class << self - # Single-select with plain string values: `{ type: "string", enum: [...] }`. - def untitled_single_select(values:, default: nil, title: nil, description: nil) - validate_values!(values) - - new( - type: "string", - extras: { enum: values }, - default: default, - title: title, - description: description, - ) - end - - # Single-select with display titles per option: `{ type: "string", oneOf: [{ const, title }, ...] }`. - # `options` is an Array of `{ value:, title: }` hashes. - def titled_single_select(options:, default: nil, title: nil, description: nil) - validate_titled_options!(options) - - new( - type: "string", - extras: { oneOf: options.map { |o| { const: o[:value], title: o[:title] } } }, - default: default, - title: title, - description: description, - ) - end - - # Multi-select with plain string values: `{ type: "array", items: { type: "string", enum: [...] } }`. - def untitled_multi_select(values:, default: nil, title: nil, description: nil) - validate_values!(values) - - new( - type: "array", - extras: { items: { type: "string", enum: values } }, - default: default, - title: title, - description: description, - ) - end - - # Multi-select with display titles per option: `{ type: "array", items: { anyOf: [{ const, title }, ...] } }`. - def titled_multi_select(options:, default: nil, title: nil, description: nil) - validate_titled_options!(options) - - items_anyof = options.map { |o| { const: o[:value], title: o[:title] } } - new( - type: "array", - extras: { items: { anyOf: items_anyof } }, - default: default, - title: title, - description: description, - ) - end - - # Legacy single-select retained for backward compatibility with clients implementing - # the pre-SEP-1330 form: `{ enum, enumNames }`. - def legacy_titled(values:, value_titles:, default: nil, title: nil, description: nil) - validate_values!(values) - unless value_titles.is_a?(Array) && value_titles.length == values.length - raise ArgumentError, "value_titles must be an Array of the same length as values" - end - - new( - type: "string", - extras: { enum: values, enumNames: value_titles }, - default: default, - title: title, - description: description, - ) - end - - private - - def validate_values!(values) - unless values.is_a?(Array) && !values.empty? - raise ArgumentError, "values must be a non-empty Array" - end - end - - def validate_titled_options!(options) - unless options.is_a?(Array) && !options.empty? - raise ArgumentError, "options must be a non-empty Array of {value:, title:} hashes" - end - - options.each do |option| - unless option.is_a?(Hash) && option.key?(:value) && option.key?(:title) - raise ArgumentError, "each option must be a Hash with :value and :title keys" - end - end - end - end - - def initialize(type:, extras:, default: nil, title: nil, description: nil) - @type = type - @extras = extras - @default = default - @title = title - @description = description - end - - def to_h - hash = { type: @type }.merge(@extras) - hash[:title] = @title if @title - hash[:description] = @description if @description - hash[:default] = @default unless @default.nil? - hash - end - end - end -end diff --git a/lib/mcp/error_codes.rb b/lib/mcp/error_codes.rb deleted file mode 100644 index 603a7a9..0000000 --- a/lib/mcp/error_codes.rb +++ /dev/null @@ -1,27 +0,0 @@ -# frozen_string_literal: true - -module MCP - # MCP-specific JSON-RPC error codes, complementing the generic codes in `JsonRpcHandler::ErrorCode`. - # - # All three constants below are introduced by the stateless lifecycle of the MCP 2026-07-28 draft (SEP-2575): - # - # - `HEADER_MISMATCH` rejects an HTTP request whose headers do not match the corresponding body values, - # or whose required headers are missing or malformed (no `error.data`). It is reserved for - # the Streamable HTTP transport, since headers do not exist on stdio. - # - `MISSING_REQUIRED_CLIENT_CAPABILITY` rejects a request that requires a client capability - # the request did not declare (`error.data: { requiredCapabilities: {...} }`). - # Raised via `Server::MissingRequiredClientCapabilityError`. - # - `UNSUPPORTED_PROTOCOL_VERSION` rejects a request whose `_meta`-carried protocol version the server - # does not support (`error.data: { supported: [...], requested: "..." }`). Raised via - # `Server::UnsupportedProtocolVersionError`. - # - # The values come from the spec's MCP-specific error code block, which is allocated sequentially from `-32020` - # toward `-32099`. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - module ErrorCodes - HEADER_MISMATCH = -32020 - MISSING_REQUIRED_CLIENT_CAPABILITY = -32021 - UNSUPPORTED_PROTOCOL_VERSION = -32022 - end -end diff --git a/lib/mcp/icon.rb b/lib/mcp/icon.rb index 56ac6ad..5758c42 100644 --- a/lib/mcp/icon.rb +++ b/lib/mcp/icon.rb @@ -1,35 +1,13 @@ # frozen_string_literal: true module MCP - # An icon attached to a server, tool, prompt, or resource, per the specification's `Icon` type: - # https://modelcontextprotocol.io/specification/2026-07-28/basic#icons - # - # Each argument is checked against the schema's type, as the TypeScript and Python SDKs check theirs, - # so an icon that would serialize into something a client rejects fails here instead. What a value means - # is not judged: `src` may be any non-empty `String` (the schema types it as a URI, which an empty `String` - # is not, and the specification allows an HTTP/HTTPS URL or a `data:` URI), and a size may be any `String` - # (the specification expects `WxH` or `"any"`). class Icon - SUPPORTED_THEMES = ["light", "dark"].freeze + SUPPORTED_THEMES = ["light", "dark"] attr_reader :mime_type, :sizes, :src, :theme - def initialize(mime_type: nil, sizes: nil, src:, theme: nil) - unless src.is_a?(String) && !src.empty? - raise ArgumentError, "The value of src must be a non-empty String (got #{src.class})." - end - - unless mime_type.nil? || mime_type.is_a?(String) - raise ArgumentError, "The value of mime_type must be a String (got #{mime_type.class})." - end - - if (problem = sizes_problem(sizes)) - raise ArgumentError, "The value of sizes must be an Array of Strings such as [\"48x48\"] or [\"any\"] (#{problem})." - end - - unless theme.nil? || SUPPORTED_THEMES.include?(theme) - raise ArgumentError, 'The value of theme must specify "light" or "dark".' - end + def initialize(mime_type: nil, sizes: nil, src: nil, theme: nil) + raise ArgumentError, 'The value of theme must specify "light" or "dark".' if theme && !SUPPORTED_THEMES.include?(theme) @mime_type = mime_type @sizes = sizes @@ -40,16 +18,5 @@ module MCP def to_h { mimeType: mime_type, sizes: sizes, src: src, theme: theme }.compact end - - private - - def sizes_problem(sizes) - return if sizes.nil? - return "got #{sizes.class}" unless sizes.is_a?(Array) - - index = sizes.index { |size| !size.is_a?(String) } - - "got #{sizes[index].class} inside the Array" if index - end end end diff --git a/lib/mcp/instrumentation.rb b/lib/mcp/instrumentation.rb index 5f1142f..40975a9 100644 --- a/lib/mcp/instrumentation.rb +++ b/lib/mcp/instrumentation.rb @@ -2,44 +2,19 @@ module MCP module Instrumentation - def instrument_call(method, server_context: {}, exception_already_reported: nil, &block) + def instrument_call(method, &block) start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC) begin @instrumentation_data = {} add_instrumentation_data(method: method) - # `self.` is required: the `server_context:` keyword above shadows the - # reader, and the value we want here is the user-defined hash passed to - # `Server.new`, not the per-call reporter context. - if configuration.instrument_server_context? && respond_to?(:server_context) - add_instrumentation_data(server_context: self.server_context) - end - result = configuration.around_request.call(@instrumentation_data, &block) + result = yield block result - rescue => e - already_reported = begin - !!exception_already_reported&.call(e) - rescue Exception - # The predicate is expected to be side-effect-free and return a boolean. - # Any exception raised from it (including non-StandardError such as SystemExit) - # must not shadow the original exception. - false - end - - unless already_reported - add_instrumentation_data(error: :internal_error) unless @instrumentation_data.key?(:error) - configuration.exception_reporter.call(e, server_context) - end - - raise ensure end_time = Process.clock_gettime(Process::CLOCK_MONOTONIC) add_instrumentation_data(duration: end_time - start_time) - # Backward compatibility: `instrumentation_callback` is soft-deprecated - # in favor of `around_request`, but existing callers still expect it - # to fire after every request until it is removed in a future version. configuration.instrumentation_callback.call(@instrumentation_data) end end diff --git a/lib/mcp/logging_message_notification.rb b/lib/mcp/logging_message_notification.rb deleted file mode 100644 index 044e4d4..0000000 --- a/lib/mcp/logging_message_notification.rb +++ /dev/null @@ -1,30 +0,0 @@ -# frozen_string_literal: true - -module MCP - class LoggingMessageNotification - LOG_LEVEL_SEVERITY = { - "debug" => 0, - "info" => 1, - "notice" => 2, - "warning" => 3, - "error" => 4, - "critical" => 5, - "alert" => 6, - "emergency" => 7, - }.freeze - - def initialize(level:) - @level = level - end - - def valid_level? - LOG_LEVEL_SEVERITY.keys.include?(@level) - end - - def should_notify?(log_level) - return false unless LOG_LEVEL_SEVERITY.key?(log_level) - - LOG_LEVEL_SEVERITY[log_level] >= LOG_LEVEL_SEVERITY[@level] - end - end -end diff --git a/lib/mcp/methods.rb b/lib/mcp/methods.rb index 60af708..bf2982f 100644 --- a/lib/mcp/methods.rb +++ b/lib/mcp/methods.rb @@ -5,12 +5,6 @@ module MCP INITIALIZE = "initialize" PING = "ping" LOGGING_SET_LEVEL = "logging/setLevel" - # Sessionless capability discovery (MCP 2026-07-28 draft, SEP-2575). - SERVER_DISCOVER = "server/discover" - # Long-lived notification subscription stream (MCP 2026-07-28, SEP-2575), - # replacing the legacy HTTP GET listening stream. Served at the transport layer - # (Streamable HTTP modern path); transports without streaming support answer `-32601`. - SUBSCRIPTIONS_LISTEN = "subscriptions/listen" PROMPTS_GET = "prompts/get" PROMPTS_LIST = "prompts/list" @@ -25,20 +19,6 @@ module MCP TOOLS_CALL = "tools/call" TOOLS_LIST = "tools/list" - # RPC methods the stateless modern lifecycle removes (MCP 2026-07-28, SEP-2575): - # `initialize` is replaced by the per-request `_meta` envelope plus `server/discover`, - # `logging/setLevel` by the envelope's `logLevel` member, and `ping` and the resource - # subscription pair by the connectionless model, which leaves nothing to keep alive - # or subscribe on. A modern-era request naming one of these answers with `-32601` - # Method not found (HTTP 404 on Streamable HTTP). - MODERN_REMOVED_METHODS = [ - INITIALIZE, - PING, - LOGGING_SET_LEVEL, - RESOURCES_SUBSCRIBE, - RESOURCES_UNSUBSCRIBE, - ].freeze - ROOTS_LIST = "roots/list" SAMPLING_CREATE_MESSAGE = "sampling/createMessage" ELICITATION_CREATE = "elicitation/create" @@ -53,10 +33,6 @@ module MCP NOTIFICATIONS_MESSAGE = "notifications/message" NOTIFICATIONS_PROGRESS = "notifications/progress" NOTIFICATIONS_CANCELLED = "notifications/cancelled" - NOTIFICATIONS_ELICITATION_COMPLETE = "notifications/elicitation/complete" - # First message on a `subscriptions/listen` stream (SEP-2575): reports the subset - # of requested notification types the server agreed to honor. - NOTIFICATIONS_SUBSCRIPTIONS_ACKNOWLEDGED = "notifications/subscriptions/acknowledged" class MissingRequiredCapabilityError < StandardError attr_reader :method @@ -70,10 +46,6 @@ module MCP end class << self - def notification?(method) - method.is_a?(String) && method.start_with?("notifications/") - end - def ensure_capability!(method, capabilities) case method when PROMPTS_GET, PROMPTS_LIST @@ -100,13 +72,15 @@ module MCP require_capability!(method, capabilities, :completions) when ROOTS_LIST require_capability!(method, capabilities, :roots) + when NOTIFICATIONS_ROOTS_LIST_CHANGED + require_capability!(method, capabilities, :roots) + require_capability!(method, capabilities, :roots, :listChanged) when SAMPLING_CREATE_MESSAGE require_capability!(method, capabilities, :sampling) when ELICITATION_CREATE require_capability!(method, capabilities, :elicitation) - when INITIALIZE, PING, SERVER_DISCOVER, NOTIFICATIONS_INITIALIZED, NOTIFICATIONS_ROOTS_LIST_CHANGED, - NOTIFICATIONS_PROGRESS, NOTIFICATIONS_CANCELLED, NOTIFICATIONS_ELICITATION_COMPLETE - # No specific capability required. + when INITIALIZE, PING, NOTIFICATIONS_INITIALIZED, NOTIFICATIONS_PROGRESS, NOTIFICATIONS_CANCELLED + # No specific capability required for initialize, ping, progress or cancelled end end diff --git a/lib/mcp/progress.rb b/lib/mcp/progress.rb deleted file mode 100644 index 6762d3c..0000000 --- a/lib/mcp/progress.rb +++ /dev/null @@ -1,24 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Progress - def initialize(notification_target:, progress_token:, related_request_id: nil) - @notification_target = notification_target - @progress_token = progress_token - @related_request_id = related_request_id - end - - def report(progress, total: nil, message: nil) - return unless @progress_token - return unless @notification_target - - @notification_target.notify_progress( - progress_token: @progress_token, - progress: progress, - total: total, - message: message, - related_request_id: @related_request_id, - ) - end - end -end diff --git a/lib/mcp/prompt.rb b/lib/mcp/prompt.rb index c2ed2db..128ee47 100644 --- a/lib/mcp/prompt.rb +++ b/lib/mcp/prompt.rb @@ -1,9 +1,5 @@ # frozen_string_literal: true -require_relative "prompt/argument" -require_relative "prompt/message" -require_relative "prompt/result" - module MCP class Prompt class << self @@ -25,7 +21,7 @@ module MCP title: title_value, description: description_value, icons: icons_value&.then { |icons| icons.empty? ? nil : icons.map(&:to_h) }, - arguments: arguments_value.empty? ? nil : arguments_value.map(&:to_h), + arguments: arguments_value&.map(&:to_h), _meta: meta_value, }.compact end @@ -36,7 +32,7 @@ module MCP subclass.instance_variable_set(:@title_value, nil) subclass.instance_variable_set(:@description_value, nil) subclass.instance_variable_set(:@icons_value, nil) - subclass.instance_variable_set(:@arguments_value, []) + subclass.instance_variable_set(:@arguments_value, nil) subclass.instance_variable_set(:@meta_value, nil) end @@ -80,7 +76,7 @@ module MCP if value == NOT_SET @arguments_value else - @arguments_value = Array(value) + @arguments_value = value end end @@ -107,19 +103,11 @@ module MCP end def validate_arguments!(args) - args ||= {} missing = required_args - args.keys return if missing.empty? - # The explicit `error_code` maps a missing prompt argument to Invalid Params (-32602) rather - # than the default Internal Error (-32603); a missing required argument is client input, not a - # server fault. `error_type: :missing_required_arguments` keeps the descriptive message and - # instrumentation label. Mirrors `MCP::Server::ResourceNotFoundError`. raise MCP::Server::RequestHandlerError.new( - "Missing required arguments: #{missing.join(", ")}", - nil, - error_type: :missing_required_arguments, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, + "Missing required arguments: #{missing.join(", ")}", nil, error_type: :missing_required_arguments ) end diff --git a/lib/mcp/prompt/result.rb b/lib/mcp/prompt/result.rb index c1fb740..b55b242 100644 --- a/lib/mcp/prompt/result.rb +++ b/lib/mcp/prompt/result.rb @@ -3,16 +3,15 @@ module MCP class Prompt class Result - attr_reader :description, :messages, :meta + attr_reader :description, :messages - def initialize(description: nil, messages: [], meta: nil) + def initialize(description: nil, messages: []) @description = description @messages = messages - @meta = meta end def to_h - { description: description, messages: messages.map(&:to_h), _meta: meta }.compact + { description: description, messages: messages.map(&:to_h) }.compact end end end diff --git a/lib/mcp/protocol_deprecations.rb b/lib/mcp/protocol_deprecations.rb deleted file mode 100644 index f79e727..0000000 --- a/lib/mcp/protocol_deprecations.rb +++ /dev/null @@ -1,61 +0,0 @@ -# frozen_string_literal: true - -require_relative "configuration" - -module MCP - # Warning texts for the features SEP-2577 deprecates at 2026-07-28. - # - # Only the client emits these, from the modern connect, where the capabilities it declares are - # the ones being deprecated. No server-side trigger remains: the `initialize` handshake never lands on - # a deprecating revision and `Configuration` rejects a modern pin, so nothing on that side can reach - # a version these apply to. `LOGGING_MESSAGE` in particular has no caller left - # (a modern client declares no logging capability, and `notify_log_message` on that wire is - # the SEP-2575 sanctioned delivery path rather than a deprecated call). It stays public and - # callable for embedders, and because deleting it would be a breaking change for no gain. - module ProtocolDeprecations - extend self - - ROOTS_MESSAGE = - "MCP Roots (`roots/list` and `notifications/roots/list_changed`) is deprecated as of protocol version " \ - "2026-07-28 (SEP-2577). Use tool parameters, resource URIs, server configuration, or environment " \ - "variables instead." - SAMPLING_MESSAGE = - "MCP Sampling (`sampling/createMessage`) is deprecated as of protocol version 2026-07-28 (SEP-2577). " \ - "Use direct LLM provider APIs instead." - LOGGING_MESSAGE = - "MCP Logging (`logging/setLevel` and `notifications/message`) is deprecated as of protocol version " \ - "2026-07-28 (SEP-2577). Use stderr or OpenTelemetry instead." - - MESSAGES = { - roots: ROOTS_MESSAGE, - sampling: SAMPLING_MESSAGE, - logging: LOGGING_MESSAGE, - }.freeze - - def deprecated_roots_sampling_logging?(protocol_version) - return false unless protocol_version - - protocol_version >= Configuration::ROOTS_SAMPLING_LOGGING_DEPRECATED_PROTOCOL_VERSION - end - - def warn_for(feature, protocol_version:, uplevel: 1) - return unless deprecated_roots_sampling_logging?(protocol_version) - - Kernel.warn(MESSAGES.fetch(feature), uplevel: uplevel) - end - - def warn_for_client_capabilities(capabilities, protocol_version:, uplevel: 1) - return unless deprecated_roots_sampling_logging?(protocol_version) - return unless capabilities - - warn_for(:roots, protocol_version: protocol_version, uplevel: uplevel) if capability?(capabilities, :roots) - warn_for(:sampling, protocol_version: protocol_version, uplevel: uplevel) if capability?(capabilities, :sampling) - end - - private - - def capability?(capabilities, key) - capabilities.key?(key) || capabilities.key?(key.to_s) - end - end -end diff --git a/lib/mcp/request_envelope.rb b/lib/mcp/request_envelope.rb deleted file mode 100644 index 3f1b19a..0000000 --- a/lib/mcp/request_envelope.rb +++ /dev/null @@ -1,117 +0,0 @@ -# frozen_string_literal: true - -module MCP - # The per-request `_meta` envelope of the stateless "modern" lifecycle (MCP 2026-07-28, SEP-2575). - # The modern lifecycle has no `initialize` handshake: every request identifies its protocol version - # and client capabilities through reserved `_meta` keys (plus an optional client identity), - # and the server validates each request independently. Servers MUST NOT infer capabilities from - # prior requests, which is why the envelope is a per-request value object rather than session state. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - class RequestEnvelope - PROTOCOL_VERSION_META_KEY = "io.modelcontextprotocol/protocolVersion" - CLIENT_INFO_META_KEY = "io.modelcontextprotocol/clientInfo" - CLIENT_CAPABILITIES_META_KEY = "io.modelcontextprotocol/clientCapabilities" - - # Optional per-request log level, replacing the `logging/setLevel` RPC in the modern lifecycle. - # Deprecated as of 2026-07-28 (SEP-2577) but still part of the wire format. - LOG_LEVEL_META_KEY = "io.modelcontextprotocol/logLevel" - # Notification-side reserved key (SEP-2575): correlates a notification delivered on - # a `subscriptions/listen` stream (and the stream's closing result) with the JSON-RPC id of - # the `subscriptions/listen` request that opened it. Not part of the request envelope triple. - SUBSCRIPTION_ID_META_KEY = "io.modelcontextprotocol/subscriptionId" - - # Result-side counterpart of the request envelope: the server's identity rides in - # the result's `_meta` as an optional stamp, not as a top-level field, since the SEP was - # finalized (spec PR modelcontextprotocol/modelcontextprotocol#3002). A server MAY omit it. - SERVER_INFO_META_KEY = "io.modelcontextprotocol/serverInfo" - - # `clientInfo` is deliberately absent: it became optional after the SEP was finalized - # (spec PR modelcontextprotocol/modelcontextprotocol#3002), so servers MUST accept - # envelopes without it. The TypeScript and Python SDKs validate the same required pair. - REQUIRED_META_KEYS = [ - PROTOCOL_VERSION_META_KEY, - CLIENT_CAPABILITIES_META_KEY, - ].freeze - - class << self - # A request claims the modern lifecycle when its `_meta` carries `io.modelcontextprotocol/protocolVersion`, - # matching the TypeScript SDK's envelope claim and the Python SDK's `_has_modern_envelope`. - # Classification is deliberately looser than validation: a claimed-but-malformed envelope is - # rejected by {parse!} with `-32602` instead of silently flowing through the legacy path, - # while `_meta` without the claim key (`progressToken`, trace context) stays legacy. - def modern?(params) - meta = extract_meta(params) - return false unless meta.is_a?(Hash) - - !read(meta, PROTOCOL_VERSION_META_KEY).nil? - end - - # Parses and validates the envelope: `protocolVersion` and `clientCapabilities` are required, - # `clientInfo` is optional. A missing or mistyped field is Invalid params (`-32602`) naming - # the offending keys, the code and shape the spec mandates and the reference SDKs emit. - # `request` is only used to enrich the raised error; callers dispatching notifications can omit it. - def parse!(params, request: nil) - meta = extract_meta(params) - meta = {} unless meta.is_a?(Hash) - - protocol_version = read(meta, PROTOCOL_VERSION_META_KEY) - client_info = read(meta, CLIENT_INFO_META_KEY) - client_capabilities = read(meta, CLIENT_CAPABILITIES_META_KEY) - - invalid_keys = [] - invalid_keys << PROTOCOL_VERSION_META_KEY unless protocol_version.is_a?(String) - invalid_keys << CLIENT_CAPABILITIES_META_KEY unless client_capabilities.is_a?(Hash) - invalid_keys << CLIENT_INFO_META_KEY unless client_info.nil? || client_info.is_a?(Hash) - - unless invalid_keys.empty? - raise Server::RequestHandlerError.new( - "Invalid params: missing or invalid `#{invalid_keys.join("`, `")}` in `_meta`", - request, - error_type: :invalid_params, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - ) - end - - unless Configuration.modern_protocol_version?(protocol_version) - raise Server::UnsupportedProtocolVersionError.new(protocol_version, request) - end - - new( - protocol_version: protocol_version, - client_info: client_info, - client_capabilities: client_capabilities, - log_level: read(meta, LOG_LEVEL_META_KEY), - ) - end - - private - - # `Server#handle` accepts hashes parsed with either symbol or string keys, so read both forms - # (the same tolerance as `Server#handle_cancelled_notification`). - def extract_meta(params) - return unless params.is_a?(Hash) - - meta = params[:_meta] - meta.nil? ? params["_meta"] : meta - end - - def read(meta, key) - value = meta[key.to_sym] - value.nil? ? meta[key] : value - end - end - - # `client_info` is `nil` when the client chose not to identify itself, which is legal: - # it is self-reported data and MUST NOT drive behavior or security decisions anyway. - attr_reader :protocol_version, :client_info, :client_capabilities, :log_level - - def initialize(protocol_version:, client_capabilities:, client_info: nil, log_level: nil) - @protocol_version = protocol_version - @client_info = client_info - @client_capabilities = client_capabilities - @log_level = log_level - freeze - end - end -end diff --git a/lib/mcp/resource.rb b/lib/mcp/resource.rb index dd87ee2..6f06d36 100644 --- a/lib/mcp/resource.rb +++ b/lib/mcp/resource.rb @@ -1,157 +1,16 @@ # frozen_string_literal: true -require_relative "resource/contents" -require_relative "resource/embedded" - module MCP class Resource - class << self - NOT_SET = Object.new + attr_reader :uri, :name, :title, :description, :icons, :mime_type - attr_reader :uri_value - attr_reader :title_value - attr_reader :description_value - attr_reader :icons_value - attr_reader :mime_type_value - attr_reader :annotations_value - attr_reader :size_value - attr_reader :meta_value - - def contents(server_context: nil) - raise NotImplementedError, "Subclasses must implement contents" - end - - def to_h - { - uri: uri_value, - name: name_value, - title: title_value, - description: description_value, - icons: icons_value&.then { |icons| icons.empty? ? nil : icons.map(&:to_h) }, - mimeType: mime_type_value, - annotations: annotations_value&.to_h, - size: size_value, - _meta: meta_value, - }.compact - end - - def inherited(subclass) - super - subclass.instance_variable_set(:@uri_value, nil) - subclass.instance_variable_set(:@name_value, nil) - subclass.instance_variable_set(:@title_value, nil) - subclass.instance_variable_set(:@description_value, nil) - subclass.instance_variable_set(:@icons_value, nil) - subclass.instance_variable_set(:@mime_type_value, nil) - subclass.instance_variable_set(:@annotations_value, nil) - subclass.instance_variable_set(:@size_value, nil) - subclass.instance_variable_set(:@meta_value, nil) - end - - def uri(value = NOT_SET) - if value == NOT_SET - @uri_value - else - @uri_value = value - end - end - - def resource_name(value = NOT_SET) - if value == NOT_SET - name_value - else - @name_value = value - end - end - - def name_value - @name_value || (name.nil? ? nil : StringUtils.handle_from_class_name(name)) - end - - def title(value = NOT_SET) - if value == NOT_SET - @title_value - else - @title_value = value - end - end - - def description(value = NOT_SET) - if value == NOT_SET - @description_value - else - @description_value = value - end - end - - def icons(value = NOT_SET) - if value == NOT_SET - @icons_value - else - @icons_value = value - end - end - - def mime_type(value = NOT_SET) - if value == NOT_SET - @mime_type_value - else - @mime_type_value = value - end - end - - def annotations(value = NOT_SET) - if value == NOT_SET - @annotations_value - else - @annotations_value = value.is_a?(Annotations) ? value : Annotations.new(**value) - end - end - - def size(value = NOT_SET) - if value == NOT_SET - @size_value - else - @size_value = value - end - end - - def meta(value = NOT_SET) - if value == NOT_SET - @meta_value - else - @meta_value = value - end - end - - def define(uri: nil, name: nil, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, size: nil, meta: nil, &block) - Class.new(self) do - uri uri - resource_name name - title title - description description - icons icons - mime_type mime_type - self.annotations(annotations) if annotations - size size - meta meta - define_singleton_method(:contents, &block) if block - end - end - end - - attr_reader :uri, :name, :title, :description, :icons, :mime_type, :annotations, :size, :meta - - def initialize(uri:, name:, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, size: nil, meta: nil) + def initialize(uri:, name:, title: nil, description: nil, icons: [], mime_type: nil) @uri = uri @name = name @title = title @description = description @icons = icons @mime_type = mime_type - @annotations = annotations - @size = size - @meta = meta end def to_h @@ -162,9 +21,6 @@ module MCP description: description, icons: icons&.then { |icons| icons.empty? ? nil : icons.map(&:to_h) }, mimeType: mime_type, - annotations: annotations&.to_h, - size: size, - _meta: meta, }.compact end end diff --git a/lib/mcp/resource/contents.rb b/lib/mcp/resource/contents.rb index a7569b0..4c3bf11 100644 --- a/lib/mcp/resource/contents.rb +++ b/lib/mcp/resource/contents.rb @@ -3,24 +3,23 @@ module MCP class Resource class Contents - attr_reader :uri, :mime_type, :meta + attr_reader :uri, :mime_type - def initialize(uri:, mime_type: nil, meta: nil) + def initialize(uri:, mime_type: nil) @uri = uri @mime_type = mime_type - @meta = meta end def to_h - { uri: uri, mimeType: mime_type, _meta: meta }.compact + { uri: uri, mime_type: mime_type }.compact end end class TextContents < Contents attr_reader :text - def initialize(text:, uri:, mime_type:, meta: nil) - super(uri: uri, mime_type: mime_type, meta: meta) + def initialize(text:, uri:, mime_type:) + super(uri: uri, mime_type: mime_type) @text = text end @@ -32,13 +31,13 @@ module MCP class BlobContents < Contents attr_reader :data - def initialize(data:, uri:, mime_type:, meta: nil) - super(uri: uri, mime_type: mime_type, meta: meta) + def initialize(data:, uri:, mime_type:) + super(uri: uri, mime_type: mime_type) @data = data end def to_h - super.merge(blob: data) + super.merge(data: data) end end end diff --git a/lib/mcp/resource/embedded.rb b/lib/mcp/resource/embedded.rb index df94fc4..9df04c6 100644 --- a/lib/mcp/resource/embedded.rb +++ b/lib/mcp/resource/embedded.rb @@ -6,7 +6,6 @@ module MCP attr_reader :resource, :annotations def initialize(resource:, annotations: nil) - @resource = resource @annotations = annotations end diff --git a/lib/mcp/resource_template.rb b/lib/mcp/resource_template.rb index 71db231..871600e 100644 --- a/lib/mcp/resource_template.rb +++ b/lib/mcp/resource_template.rb @@ -2,166 +2,15 @@ module MCP class ResourceTemplate - class << self - NOT_SET = Object.new + attr_reader :uri_template, :name, :title, :description, :icons, :mime_type - # Applied after `Regexp.escape`, which turns `{` and `}` into `\{` and `\}`. - # Variable names are restricted to valid Regexp named-group names, - # so RFC 6570 operator expressions (e.g. `{?query}`) stay literal and never match. - VARIABLE_PATTERN = /\\\{([A-Za-z_]\w*)\\\}/.freeze - - attr_reader :uri_template_value - attr_reader :title_value - attr_reader :description_value - attr_reader :icons_value - attr_reader :mime_type_value - attr_reader :annotations_value - attr_reader :meta_value - - def contents(server_context: nil, **params) - raise NotImplementedError, "Subclasses must implement contents" - end - - def to_h - { - uriTemplate: uri_template_value, - name: name_value, - title: title_value, - description: description_value, - icons: icons_value&.then { |icons| icons.empty? ? nil : icons.map(&:to_h) }, - mimeType: mime_type_value, - annotations: annotations_value&.to_h, - _meta: meta_value, - }.compact - end - - def inherited(subclass) - super - subclass.instance_variable_set(:@uri_template_value, nil) - subclass.instance_variable_set(:@uri_template_pattern, nil) - subclass.instance_variable_set(:@name_value, nil) - subclass.instance_variable_set(:@title_value, nil) - subclass.instance_variable_set(:@description_value, nil) - subclass.instance_variable_set(:@icons_value, nil) - subclass.instance_variable_set(:@mime_type_value, nil) - subclass.instance_variable_set(:@annotations_value, nil) - subclass.instance_variable_set(:@meta_value, nil) - end - - def uri_template(value = NOT_SET) - if value == NOT_SET - @uri_template_value - else - @uri_template_pattern = nil - @uri_template_value = value - end - end - - def resource_template_name(value = NOT_SET) - if value == NOT_SET - name_value - else - @name_value = value - end - end - - def name_value - @name_value || (name.nil? ? nil : StringUtils.handle_from_class_name(name)) - end - - def title(value = NOT_SET) - if value == NOT_SET - @title_value - else - @title_value = value - end - end - - def description(value = NOT_SET) - if value == NOT_SET - @description_value - else - @description_value = value - end - end - - def icons(value = NOT_SET) - if value == NOT_SET - @icons_value - else - @icons_value = value - end - end - - def mime_type(value = NOT_SET) - if value == NOT_SET - @mime_type_value - else - @mime_type_value = value - end - end - - def annotations(value = NOT_SET) - if value == NOT_SET - @annotations_value - else - @annotations_value = value.is_a?(Annotations) ? value : Annotations.new(**value) - end - end - - def meta(value = NOT_SET) - if value == NOT_SET - @meta_value - else - @meta_value = value - end - end - - # Matches a concrete URI against the template's simple RFC 6570 level-1 `{var}` expressions. - # Returns a symbol-keyed Hash of variable values, or `nil` if the URI does not match. - # Variables match one or more characters excluding `/`, and values are not percent-decoded. - def match_uri(uri) - match = uri_template_pattern&.match(uri) - match&.named_captures&.transform_keys(&:to_sym) - end - - def define(uri_template: nil, name: nil, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, meta: nil, &block) - Class.new(self) do - uri_template uri_template - resource_template_name name - title title - description description - icons icons - mime_type mime_type - self.annotations(annotations) if annotations - meta meta - define_singleton_method(:contents, &block) if block - end - end - - private - - def uri_template_pattern - return if uri_template.nil? - - @uri_template_pattern ||= begin - pattern = Regexp.escape(uri_template).gsub(VARIABLE_PATTERN) { "(?<#{Regexp.last_match(1)}>[^/]+)" } - Regexp.new("\\A#{pattern}\\z") - end - end - end - - attr_reader :uri_template, :name, :title, :description, :icons, :mime_type, :annotations, :meta - - def initialize(uri_template:, name:, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, meta: nil) + def initialize(uri_template:, name:, title: nil, description: nil, icons: [], mime_type: nil) @uri_template = uri_template @name = name @title = title @description = description @icons = icons @mime_type = mime_type - @annotations = annotations - @meta = meta end def to_h @@ -172,8 +21,6 @@ module MCP description: description, icons: icons&.then { |icons| icons.empty? ? nil : icons.map(&:to_h) }, mimeType: mime_type, - annotations: annotations&.to_h, - _meta: meta, }.compact end end diff --git a/lib/mcp/result_type.rb b/lib/mcp/result_type.rb deleted file mode 100644 index 9eeb394..0000000 --- a/lib/mcp/result_type.rb +++ /dev/null @@ -1,18 +0,0 @@ -# frozen_string_literal: true - -module MCP - # Values of the `resultType` result field introduced by SEP-2322 (Multi Round-Trip Requests) - # for the MCP 2026-07-28 draft. - # - # A result with `resultType: "input_required"` is not a final answer: it carries an `inputRequests` map - # of server-to-client requests (`sampling/createMessage`, `roots/list`, `elicitation/create` shapes) plus - # an opaque `requestState` string, and the client is expected to fulfill the requests and re-issue - # the original request with `inputResponses` and the echoed `requestState`. A missing `resultType` - # or `"complete"` is a final result. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2322 - module ResultType - COMPLETE = "complete" - INPUT_REQUIRED = "input_required" - end -end diff --git a/lib/mcp/server.rb b/lib/mcp/server.rb index 051a892..e5b4711 100644 --- a/lib/mcp/server.rb +++ b/lib/mcp/server.rb @@ -1,22 +1,8 @@ # frozen_string_literal: true -require "securerandom" - require_relative "../json_rpc_handler" -require_relative "cancellation" -require_relative "cancelled_error" require_relative "instrumentation" require_relative "methods" -require_relative "logging_message_notification" -require_relative "progress" -require_relative "protocol_deprecations" -require_relative "server_context" -require_relative "server/capabilities" -require_relative "server/input_required_result" -require_relative "server/pagination" -require_relative "server/pending_response" -require_relative "server/request_state_security" -require_relative "server/transports" module MCP class ToolNotUnique < StandardError @@ -31,121 +17,15 @@ module MCP class Server DEFAULT_VERSION = "0.1.0" - UNSUPPORTED_PROPERTIES_UNTIL_2025_06_18 = [:description, :icons].freeze - UNSUPPORTED_PROPERTIES_UNTIL_2025_03_26 = [:title, :websiteUrl].freeze - - DEFAULT_COMPLETION_RESULT = { completion: { values: [], hasMore: false } }.freeze - - # Servers return an array of completion values ranked by relevance, with maximum 100 items per response. - # https://modelcontextprotocol.io/specification/2025-11-25/server/utilities/completion#completion-results - MAX_COMPLETION_VALUES = 100 - class RequestHandlerError < StandardError - attr_reader :error_type, :original_error, :error_code, :error_data + attr_reader :error_type + attr_reader :original_error - def initialize(message, request, error_type: :internal_error, original_error: nil, error_code: nil, error_data: nil) + def initialize(message, request, error_type: :internal_error, original_error: nil) super(message) @request = request @error_type = error_type @original_error = original_error - @error_code = error_code - @error_data = error_data - end - end - - class URLElicitationRequiredError < RequestHandlerError - def initialize(elicitations) - super( - "URL elicitation required", - nil, - error_type: :url_elicitation_required, - error_code: -32042, - error_data: { elicitations: elicitations }, - ) - end - end - - # Raised when a request carries a protocol version the server does not support under the stateless lifecycle of - # MCP 2026-07-28 (SEP-2575). Maps to JSON-RPC error `-32022` with `data: { supported: [...], requested: "..." }` - # so the client can select a mutually supported version and retry. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - class UnsupportedProtocolVersionError < RequestHandlerError - # No keyword parameters here: with one present, Ruby 2.7 would split a trailing symbol-keyed `request` Hash - # into keywords and fail with "unknown keywords". - def initialize(requested, request = nil) - super( - "Unsupported protocol version", - request, - error_type: :unsupported_protocol_version, - error_code: ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, - error_data: { supported: Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, requested: requested || "unknown" }, - ) - end - end - - # Raised when processing a request requires a client capability the request did not declare in `_meta` - # (`io.modelcontextprotocol/clientCapabilities`). Per SEP-2575, servers MUST NOT rely on capabilities - # the client has not declared. Maps to JSON-RPC error `-32021` with `data: { requiredCapabilities: {...} }` - # listing the missing capabilities. - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - class MissingRequiredClientCapabilityError < RequestHandlerError - def initialize(required_capabilities, request = nil) - super( - "Missing required client capability", - request, - error_type: :missing_required_client_capability, - error_code: ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY, - error_data: { requiredCapabilities: required_capabilities }, - ) - end - end - - # Raised when a requested resource URI does not exist. Per SEP-2164, - # resource-not-found errors use the standard JSON-RPC Invalid Params code (-32602) - # with the requested URI in the error `data` member. Raise this from - # a `resources_read_handler` block for unknown URIs: - # - # server.resources_read_handler do |params| - # raise MCP::Server::ResourceNotFoundError.new(params[:uri], params) unless known?(params[:uri]) - # do_something(params[:uri]) - # end - # - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2164 - class ResourceNotFoundError < RequestHandlerError - def initialize(uri, request = nil) - # The explicit `error_code` keeps the descriptive message in the JSON-RPC - # error response; `error_type: :invalid_params` alone would replace it - # with the generic "Invalid params" string. - super( - "Resource not found: #{uri}", - request, - error_type: :invalid_params, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - error_data: { uri: uri }, - ) - end - end - - # Raised when a server-to-client request (sampling, elicitation, `roots/list`, `ping`) goes unanswered past its timeout. - # The spec asks implementations to bound every sent request so a peer that never answers cannot exhaust the sender's resources, - # and to cancel the request on expiry; the transport sends `notifications/cancelled` before raising this. - # These requests exist only on connections speaking 2025-11-25 or earlier, since the modern lifecycle forbids them. - # - # Left uncaught in a handler, this answers the client's originating request with `-32001` rather than a generic - # internal error, so the peer that failed to answer can tell a timeout apart from a server fault. The code is not - # spec-allocated: it sits in the implementation-defined server range and is the value the Python SDK reports for - # this condition, so a client that already recognizes it there reads the same meaning here. - # - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#timeouts - class RequestTimeoutError < RequestHandlerError - attr_reader :request_id, :timeout - - def initialize(message, request_id:, timeout:) - super(message, nil, error_type: :request_timeout, error_code: -32001) - @request_id = request_id - @timeout = timeout end end @@ -158,31 +38,9 @@ module MCP end end - # Raised when a client response fails server-side validation, e.g., a success response - # whose `result` field is missing or has the wrong type. This is distinct from a - # client-returned JSON-RPC error. - class ValidationError < StandardError; end - include Instrumentation - include Pagination - # Allowed values for the SEP-2549 `cacheScope` cache hint. - CACHE_SCOPES = ["public", "private"].freeze - - # Methods whose results are cacheable per SEP-2549. - # On the modern wire (2026-07-28) the `ttlMs`/`cacheScope` hints are REQUIRED on these results, - # so unset hints get the spec defaults there; on stable protocol versions emission stays opt-in - # via `apply_cache_metadata`. - CACHEABLE_RESULT_METHODS = [ - Methods::TOOLS_LIST, - Methods::PROMPTS_LIST, - Methods::RESOURCES_LIST, - Methods::RESOURCES_TEMPLATES_LIST, - Methods::RESOURCES_READ, - ].freeze - - attr_accessor :description, :icons, :name, :title, :version, :website_url, :instructions, :tools, :prompts, :resource_templates, :server_context, :configuration, :capabilities, :transport, :logging_message_notification - attr_reader :resources, :page_size, :client_capabilities, :ttl_ms, :cache_scope, :request_state_security + attr_accessor :description, :icons, :name, :title, :version, :website_url, :instructions, :tools, :prompts, :resources, :server_context, :configuration, :capabilities, :transport def initialize( description: nil, @@ -199,11 +57,6 @@ module MCP server_context: nil, configuration: nil, capabilities: nil, - page_size: nil, - ttl_ms: nil, - cache_scope: nil, - request_state_security: nil, - input_required_legacy_shim: true, transport: nil ) @description = description @@ -219,83 +72,49 @@ module MCP @resources = resources @resource_templates = resource_templates @resource_index = index_resources_by_uri(resources) - @resources_list_handler = nil @server_context = server_context - self.page_size = page_size - self.ttl_ms = ttl_ms - self.cache_scope = cache_scope - @request_state_security = request_state_security - - # Dual-era authoring (SEP-2322): on the legacy wire, an `input_required` result is fulfilled - # through real server-to-client requests and the handler re-runs, so handlers written - # in the 2026 style serve both eras. `false` restores the strict rejection of `input_required` - # on legacy requests. Matches the TypeScript SDK's default-on legacy shim. - @input_required_legacy_shim = input_required_legacy_shim @configuration = MCP.configuration.merge(configuration) - @client = nil - @client_protocol_version = nil validate! - # Accept either a plain Hash or an `MCP::Server::Capabilities` builder. - @capabilities = if capabilities.is_a?(Capabilities) - capabilities.to_h - else - capabilities || default_capabilities - end - @client_capabilities = nil - @logging_message_notification = nil + @capabilities = capabilities || default_capabilities @handlers = { Methods::RESOURCES_LIST => method(:list_resources), - Methods::RESOURCES_READ => method(:read_resource), + Methods::RESOURCES_READ => method(:read_resource_no_content), Methods::RESOURCES_TEMPLATES_LIST => method(:list_resource_templates), - Methods::RESOURCES_SUBSCRIBE => ->(_) { {} }, - Methods::RESOURCES_UNSUBSCRIBE => ->(_) { {} }, Methods::TOOLS_LIST => method(:list_tools), Methods::TOOLS_CALL => method(:call_tool), Methods::PROMPTS_LIST => method(:list_prompts), Methods::PROMPTS_GET => method(:get_prompt), Methods::INITIALIZE => method(:init), - Methods::SERVER_DISCOVER => method(:discover), Methods::PING => ->(_) { {} }, Methods::NOTIFICATIONS_INITIALIZED => ->(_) {}, - Methods::NOTIFICATIONS_PROGRESS => ->(_) {}, - Methods::NOTIFICATIONS_ROOTS_LIST_CHANGED => ->(_) {}, - Methods::COMPLETION_COMPLETE => ->(_) { DEFAULT_COMPLETION_RESULT }, - Methods::LOGGING_SET_LEVEL => method(:configure_logging_level), + + # No op handlers for currently unsupported methods + Methods::RESOURCES_SUBSCRIBE => ->(_) {}, + Methods::RESOURCES_UNSUBSCRIBE => ->(_) {}, + Methods::COMPLETION_COMPLETE => ->(_) {}, + Methods::LOGGING_SET_LEVEL => ->(_) {}, + Methods::ELICITATION_CREATE => ->(_) {}, } @transport = transport end - # Processes a parsed JSON-RPC request and returns the response as a Hash. - # - # @param request [Hash] A parsed JSON-RPC request. - # @param session [ServerSession, nil] Per-connection session. Passed by - # `ServerSession#handle` for session-scoped notification delivery. - # When `nil`, progress and logging notifications from tool handlers are silently skipped. - # @return [Hash, nil] The JSON-RPC response, or `nil` for notifications. - def handle(request, session: nil) - JsonRpcHandler.handle(request) do |method, request_id| - handle_request(request, method, session: session, related_request_id: request_id) + def handle(request) + JsonRpcHandler.handle(request) do |method| + handle_request(request, method) end end - # Processes a JSON-RPC request string and returns the response as a JSON string. - # - # @param request [String] A JSON-RPC request as a JSON string. - # @param session [ServerSession, nil] Per-connection session. Passed by - # `ServerSession#handle_json` for session-scoped notification delivery. - # When `nil`, progress and logging notifications from tool handlers are silently skipped. - # @return [String, nil] The JSON-RPC response as JSON, or `nil` for notifications. - def handle_json(request, session: nil) - JsonRpcHandler.handle_json(request) do |method, request_id| - handle_request(request, method, session: session, related_request_id: request_id) + def handle_json(request) + JsonRpcHandler.handle_json(request) do |method| + handle_request(request, method) end end - def define_tool(name: nil, title: nil, description: nil, input_schema: nil, output_schema: nil, annotations: nil, meta: nil, &block) - tool = Tool.define(name: name, title: title, description: description, input_schema: input_schema, output_schema: output_schema, annotations: annotations, meta: meta, &block) + def define_tool(name: nil, title: nil, description: nil, input_schema: nil, annotations: nil, meta: nil, &block) + tool = Tool.define(name: name, title: title, description: description, input_schema: input_schema, annotations: annotations, meta: meta, &block) tool_name = tool.name_value @tool_names << tool_name @@ -311,34 +130,6 @@ module MCP validate! end - def define_resource(uri: nil, name: nil, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, size: nil, meta: nil, &block) - resource = Resource.define( - uri: uri, name: name, title: title, description: description, icons: icons, - mime_type: mime_type, annotations: annotations, size: size, meta: meta, - &block - ) - @resources << resource - @resource_index[resource.uri] = resource - - validate! - end - - def define_resource_template(uri_template: nil, name: nil, title: nil, description: nil, icons: [], mime_type: nil, annotations: nil, meta: nil, &block) - resource_template = ResourceTemplate.define( - uri_template: uri_template, name: name, title: title, description: description, icons: icons, - mime_type: mime_type, annotations: annotations, meta: meta, - &block - ) - @resource_templates << resource_template - - validate! - end - - def resources=(resources) - @resources = resources - @resource_index = index_resources_by_uri(resources) - end - def define_custom_method(method_name:, &block) if @handlers.key?(method_name) raise MethodAlreadyDefinedError, method_name @@ -347,35 +138,6 @@ module MCP @handlers[method_name] = block end - def page_size=(page_size) - unless page_size.nil? || (page_size.is_a?(Integer) && page_size > 0) - raise ArgumentError, "page_size must be nil or a positive integer" - end - - @page_size = page_size - end - - # SEP-2549 cache hint: freshness lifetime in milliseconds for list and read results - # (max-age semantics; 0 means do not cache). Emission is opt-in: when both `ttl_ms` - # and `cache_scope` are nil, results are serialized exactly as before. - def ttl_ms=(ttl_ms) - unless ttl_ms.nil? || (ttl_ms.is_a?(Integer) && ttl_ms >= 0) - raise ArgumentError, "ttl_ms must be nil or a non-negative integer" - end - - @ttl_ms = ttl_ms - end - - # SEP-2549 cache hint: whether shared intermediaries may cache the result ("public") - # or only the requesting client ("private"). - def cache_scope=(cache_scope) - unless cache_scope.nil? || CACHE_SCOPES.include?(cache_scope) - raise ArgumentError, "cache_scope must be nil, \"public\", or \"private\"" - end - - @cache_scope = cache_scope - end - def notify_tools_list_changed return unless @transport @@ -400,129 +162,32 @@ module MCP report_exception(e, { notification: "resources_list_changed" }) end - # @deprecated MCP Logging (`logging/setLevel` and `notifications/message`) - # is deprecated as of MCP protocol version 2026-07-28 (SEP-2577). - # Use stderr or OpenTelemetry instead. - def notify_log_message(data:, level:, logger: nil) - return unless @transport - return unless logging_message_notification&.should_notify?(level) - - params = { "data" => data, "level" => level } - params["logger"] = logger if logger - - @transport.send_notification(Methods::NOTIFICATIONS_MESSAGE, params) - rescue => e - report_exception(e, { notification: "log_message" }) - end - - # Sets a handler for `notifications/roots/list_changed` notifications. - # Called when a client notifies the server that its filesystem roots have changed. - # - # @yield [params] The notification params (typically `nil`). - # @deprecated MCP Roots (`roots/list` and - # `notifications/roots/list_changed`) is deprecated as of MCP protocol - # version 2026-07-28 (SEP-2577). Use tool parameters, resource URIs, - # server configuration, or environment variables instead. - def roots_list_changed_handler(&block) - @handlers[Methods::NOTIFICATIONS_ROOTS_LIST_CHANGED] = block - end - - # Sets a custom handler for `resources/list` requests, letting the visible list depend on request context such as - # the authenticated principal or granted scope. The block returns the resource collection to serve; - # the framework paginates it and stamps SEP-2549 cache hints exactly as it does for the constructor-provided resources, - # so the block returns only the array, not the paginated result. - # A block that declares a `server_context:` keyword receives an `MCP::ServerContext`. When no handler is set, - # the constructor-provided `resources` array is served unchanged. - # - # The block is invoked once per page, so it must return a stable ordering across the pages of one logical query; - # the cursor is a positional offset into the returned collection. - # - # @yield [params, server_context:] The request params, and an `MCP::ServerContext` when declared. - # @yieldreturn [Array] The resources to paginate. def resources_list_handler(&block) - @resources_list_handler = block + @handlers[Methods::RESOURCES_LIST] = block end - # Sets a custom handler for `resources/read` requests. - # The block receives the parsed request params and should return resource - # contents. The return value is set as the `contents` field of the response. - # - # @yield [params] The request params containing `:uri`. - # @yieldreturn [Array, Hash] Resource contents. def resources_read_handler(&block) @handlers[Methods::RESOURCES_READ] = block end - # Sets a custom handler for `completion/complete` requests. - # The block receives the parsed request params and should return completion values. - # - # @yield [params] The request params containing `:ref`, `:argument`, and optionally `:context`. - # @yieldreturn [Hash] A hash with `:completion` key containing `:values`, optional `:total`, and `:hasMore`. - def completion_handler(&block) - @handlers[Methods::COMPLETION_COMPLETE] = block + def resources_templates_list_handler(&block) + @handlers[Methods::RESOURCES_TEMPLATES_LIST] = block end - # Sets a custom handler for `resources/subscribe` requests. - # The block receives the parsed request params. The response is an empty result, except that - # a `_meta` hash the block returns is passed through - the spec defines no other member for this result, - # so any other field the block returns is dropped. Nest a subscription identifier or other advisory data - # under `_meta`. - # - # @yield [params] The request params containing `:uri`. - # @yieldreturn [Hash, nil] Optionally `{ _meta: { ... } }`; any other shape yields an empty result. - def resources_subscribe_handler(&block) - @handlers[Methods::RESOURCES_SUBSCRIBE] = block + def tools_list_handler(&block) + @handlers[Methods::TOOLS_LIST] = block end - # Sets a custom handler for `resources/unsubscribe` requests. - # The block receives the parsed request params. The response is an empty result, except that - # a `_meta` hash the block returns is passed through - the spec defines no other member for this result, - # so any other field the block returns is dropped. Nest a subscription identifier or other advisory data - # under `_meta`. - # - # @yield [params] The request params containing `:uri`. - # @yieldreturn [Hash, nil] Optionally `{ _meta: { ... } }`; any other shape yields an empty result. - def resources_unsubscribe_handler(&block) - @handlers[Methods::RESOURCES_UNSUBSCRIBE] = block + def tools_call_handler(&block) + @handlers[Methods::TOOLS_CALL] = block end - def build_sampling_params( - capabilities, - messages:, - max_tokens:, - system_prompt: nil, - model_preferences: nil, - include_context: nil, - temperature: nil, - stop_sequences: nil, - metadata: nil, - tools: nil, - tool_choice: nil - ) - unless capabilities&.dig(:sampling) - raise "Client does not support sampling." - end + def prompts_list_handler(&block) + @handlers[Methods::PROMPTS_LIST] = block + end - if tools && !capabilities.dig(:sampling, :tools) - raise "Client does not support sampling with tools." - end - - if tool_choice && !capabilities.dig(:sampling, :tools) - raise "Client does not support sampling with tool_choice." - end - - { - messages: messages, - maxTokens: max_tokens, - systemPrompt: system_prompt, - modelPreferences: model_preferences, - includeContext: include_context, - temperature: temperature, - stopSequences: stop_sequences, - metadata: metadata, - tools: tools, - toolChoice: tool_choice, - }.compact + def prompts_get_handler(&block) + @handlers[Methods::PROMPTS_GET] = block end private @@ -536,14 +201,6 @@ module MCP message = "Error occurred in server_info. `description` is not supported in protocol version 2025-06-18 or earlier" raise ArgumentError, message end - - tools_with_ref = @tools.each_with_object([]) do |(tool_name, tool), names| - names << tool_name if schema_contains_ref?(tool.input_schema_value.to_h) - end - unless tools_with_ref.empty? - message = "Error occurred in #{tools_with_ref.join(", ")}. `$ref` in input schemas is supported by protocol version 2025-11-25 or higher" - raise ArgumentError, message - end end if @configuration.protocol_version <= "2025-03-26" @@ -584,467 +241,49 @@ module MCP raise ToolNotUnique, duplicated_tool_names unless duplicated_tool_names.empty? end - def schema_contains_ref?(schema) - case schema - when Hash - schema.any? { |key, value| key.to_s == "$ref" || schema_contains_ref?(value) } - when Array - schema.any? { |element| schema_contains_ref?(element) } - else - false - end - end - - def handle_request(request, method, session: nil, related_request_id: nil) - # A well-formed notification carries no JSON-RPC id and receives no response. - # If a client erroneously sends a notification-only method with an id, the message - # is framed as a request; since notification methods have no request handler, - # returning `nil` here makes `JsonRpcHandler` report "Method not found", matching - # the TypeScript and Python SDKs rather than emitting a spurious `result: null`. - return if Methods.notification?(method) && !related_request_id.nil? - - # `notifications/cancelled` is dispatched directly: it is a notification (no JSON-RPC id) - # and intentionally bypasses the `@handlers` lookup, capability check, in-flight registry, - # and rescue blocks below. - if method == Methods::NOTIFICATIONS_CANCELLED - return ->(params) { handle_cancelled_notification(params, session: session) } - end - + def handle_request(request, method) handler = @handlers[method] unless handler - instrument_call("unsupported_method", server_context: { request: request }) do - client = session&.client || @client - add_instrumentation_data(client: client) if client - end + instrument_call("unsupported_method") {} return end - # SEP-2575 removes these RPCs from the modern lifecycle, so they answer with Method not found - # there regardless of the server's declared capabilities: in this era the method does not exist - # at all, which is why the check precedes `ensure_capability!`. - if Methods::MODERN_REMOVED_METHODS.include?(method) && modern_request?(request, session) - raise RequestHandlerError.new( - "Method not found: #{method} is not part of the modern lifecycle (SEP-2575)", - request, - error_type: :method_not_found, - error_code: JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, - ) - end - - begin - Methods.ensure_capability!(method, capabilities) - rescue Methods::MissingRequiredCapabilityError => e - # Re-raise through RequestHandlerError, the one channel whose message is - # deliberately surfaced to clients: `JsonRpcHandler`'s blind `rescue StandardError` - # no longer echoes exception messages into the error `data` member (CWE-209). - raise RequestHandlerError.new(e.message, request, error_type: :internal_error, original_error: e) - end - - # `initialize` MUST NOT be cancelled (MCP spec 2025-11-25, cancellation item 2), - # so do not track it in the in-flight registry. - cancellation = nil - if related_request_id && method != Methods::INITIALIZE && session - cancellation = session.register_in_flight(related_request_id) - - # The spec puts the uniqueness obligation on the sender - "The request ID MUST NOT have been previously used by - # the requestor within the same session" - and says nothing about what a receiver does with a duplicate. - # Answering one is the only option that stays correct: the id routes request-scoped messages back to - # the request that caused them, and the transport's rule is that those messages "SHOULD relate to - # the originating client request", which a second live request under the same id makes impossible to honor - # for either of them. Refused the same way a duplicate `initialize` is, and for the same reason: - # so that a repeated id cannot silently displace state negotiated by the first one. - if cancellation.nil? - raise RequestHandlerError.new( - "Invalid Request: request id #{related_request_id.inspect} is already in flight", - request, - error_type: :invalid_request, - ) - end - end + Methods.ensure_capability!(method, capabilities) ->(params) { - reported_exception = nil - instrument_call( - method, - server_context: { request: request }, - exception_already_reported: ->(e) { reported_exception.equal?(e) }, - ) do - envelope = lift_request_envelope(params, method: method, session: session) - - # The envelope's `logLevel` member replaces `logging/setLevel` in the modern lifecycle: - # it authorizes `notifications/message` for this request only (SEP-2575). Without it, - # `ServerSession#notify_log_message` stays silent on modern-era sessions. An unrecognized level - # reads as absent, so delivery stays off (the safe direction), matching the Python SDK. - if envelope&.log_level && session.respond_to?(:configure_logging) - request_logging = LoggingMessageNotification.new(level: envelope.log_level) - session.configure_logging(request_logging) if request_logging.valid_level? - end - - params = unseal_request_state(params, method: method) if @request_state_security - - result = case method - when Methods::INITIALIZE - init(params, session: session) + instrument_call(method) do + case method + when Methods::TOOLS_LIST + { tools: @handlers[Methods::TOOLS_LIST].call(params) } + when Methods::PROMPTS_LIST + { prompts: @handlers[Methods::PROMPTS_LIST].call(params) } + when Methods::RESOURCES_LIST + { resources: @handlers[Methods::RESOURCES_LIST].call(params) } when Methods::RESOURCES_READ - contents = read_resource_contents(params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) - - # An SEP-2322 `input_required` result must not be wrapped as `contents` or stamped with SEP-2549 cache hints. - contents.is_a?(InputRequiredResult) ? contents : build_read_resource_result(contents) - when Methods::RESOURCES_SUBSCRIBE, Methods::RESOURCES_UNSUBSCRIBE - validate_resource_subscription_params!(params) - handler_result = dispatch_optional_context_handler(@handlers[method], params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) - - subscription_result(handler_result) - when Methods::TOOLS_CALL - call_tool(params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) - when Methods::PROMPTS_GET - get_prompt(params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) - when Methods::COMPLETION_COMPLETE - complete(params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) - when Methods::LOGGING_SET_LEVEL - configure_logging_level(params, session: session) + { contents: @handlers[Methods::RESOURCES_READ].call(params) } + when Methods::RESOURCES_TEMPLATES_LIST + { resourceTemplates: @handlers[Methods::RESOURCES_TEMPLATES_LIST].call(params) } else - dispatch_optional_context_handler(@handlers[method], params, session: session, related_request_id: related_request_id, cancellation: cancellation, envelope: envelope) + @handlers[method].call(params) end - client = session&.client || @client - add_instrumentation_data(client: client) if client - - if cancellation&.cancelled? - add_instrumentation_data(cancelled: true, cancellation_reason: cancellation.reason) - next JsonRpcHandler::NO_RESPONSE - end - - # Runs after the cancellation check so a cancelled request stays suppressed - # instead of turning into a gate error response. - if result.is_a?(InputRequiredResult) - result = if envelope.nil? && @input_required_legacy_shim && session - run_legacy_input_required_shim( - result, - method: method, - params: params, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - ) - else - serialize_input_required_result(result, envelope: envelope, request: params, method: method) - end - end - - # SEP-2322 makes `resultType` REQUIRED on every result a 2026-07-28 server returns; - # a missing value is only tolerated FROM earlier protocol versions. Results that already carry - # a discriminator keep it; everything else on the modern wire is the standard shape, - # `"complete"`. Legacy results stay unstamped: pre-2026 clients do not know the field. - if envelope && result.is_a?(Hash) && !result.key?(:resultType) - result = result.merge(resultType: ResultType::COMPLETE) - end - - # SEP-2549 makes the `ttlMs`/`cacheScope` hints REQUIRED on cacheable results at 2026-07-28, - # so unconfigured servers get `ttlMs: 0` (do not cache) and `cacheScope: "private"`: - # the spec names no default scope, and `"private"` is the side that cannot leak - # a user-dependent result through a shared cache, matching the TypeScript SDK's default - # and `server/discover`. Values already in the result win. - # Only complete results are cacheable: an SEP-2322 `input_required` round trip must not be stamped - # (the stamp above guarantees `resultType` is present on every modern Hash result by this point). - if envelope && result.is_a?(Hash) && CACHEABLE_RESULT_METHODS.include?(method) && - result[:resultType] == ResultType::COMPLETE && !(result.key?(:ttlMs) && result.key?(:cacheScope)) - result = { ttlMs: @ttl_ms || 0, cacheScope: @cache_scope || "private" }.merge(result) - end - - result - rescue CancelledError => e - add_instrumentation_data(cancelled: true, cancellation_reason: e.reason) - next JsonRpcHandler::NO_RESPONSE - rescue RequestHandlerError => e - report_exception(e.original_error || e, { request: request }) - add_instrumentation_data(error: e.error_type) - reported_exception = e - raise e rescue => e report_exception(e, { request: request }) + if e.is_a?(RequestHandlerError) + add_instrumentation_data(error: e.error_type) + raise e + end + add_instrumentation_data(error: :internal_error) - wrapped = RequestHandlerError.new("Internal error handling #{method} request", request, original_error: e) - reported_exception = wrapped - raise wrapped - ensure - # `cancellation` is non-nil exactly when this request claimed the id above, so this also keeps `initialize` - # (which never registers) from evicting an in-flight registration under a reused id when the duplicate-`initialize` - # refusal raises out of the handler. - session&.unregister_in_flight(related_request_id, cancellation: cancellation) if related_request_id && cancellation + raise RequestHandlerError.new("Internal error handling #{method} request", request, original_error: e) end } end - # Whether this request belongs to the modern lifecycle, used to refuse the RPCs SEP-2575 removed from it. - # A locked `ServerSession#era` is authoritative; until it locks, the request's own `_meta` envelope is - # the signal. Both are needed because `StdioTransport` locks the era only after a response succeeds, - # which would otherwise let the first request of a connection reach a method the modern lifecycle does not have. - # The Python SDK gates the same way, on the envelope of each request rather than on connection state that - # is only settled afterwards. - # - # A legacy-locked session is deliberately excluded: `lift_request_envelope` answers a modern envelope there - # with the lifecycle violation, which names the cause better than Method not found. - def modern_request?(request, session) - era = session.respond_to?(:era) ? session.era : nil - return true if era == :modern - return false unless era.nil? - - RequestEnvelope.modern?(request.is_a?(Hash) ? request[:params] : nil) - end - - # Lifts the SEP-2575 per-request `_meta` envelope for modern requests. Only a request whose `_meta` carries - # the full required triple is classified as modern; a partial triple keeps flowing through the legacy path untouched. - # Notifications carry no envelope (their `_meta` is a `NotificationMetaObject`), and `server/discover` is - # pre-version discovery, so both are exempt. Era-locked sessions additionally enforce the dual-era rules: - # on a modern session, `initialize` is rejected with `-32022` (the modern lifecycle has no handshake) - # and the triple becomes required for every other request; on a legacy session, a modern envelope is rejected as - # an invalid request because a connection can never change eras. - def lift_request_envelope(params, method:, session:) - return if Methods.notification?(method) - - era = session.respond_to?(:era) ? session.era : nil - - # Outside the modern era, `server/discover` stays envelope-exempt so legacy connections can probe capabilities - # before any negotiation. Under the modern era every request carries the envelope, discovery included: - # the conformance suite's 2026-07-28 requirements reject an envelope-less `server/discover` with `-32602` (SEP-2575). - return if method == Methods::SERVER_DISCOVER && era != :modern - - if RequestEnvelope.modern?(params) - if era == :legacy - raise RequestHandlerError.new( - "Invalid Request: the session already negotiated the legacy lifecycle via `initialize`", - params, - error_type: :invalid_request, - ) - end - - RequestEnvelope.parse!(params, request: params) - elsif era == :modern - # A claim-less request on a modern session is a malformed envelope, not a malformed request: - # the spec maps missing required envelope fields to Invalid params (`-32602`), - # and the reference SDKs answer it naming the missing keys. - raise RequestHandlerError.new( - "Invalid params: missing or invalid `#{RequestEnvelope::REQUIRED_META_KEYS.join("`, `")}` in `_meta`", - params, - error_type: :invalid_params, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - ) - end - end - - # Central gate and serializer for SEP-2322 `input_required` results, run once in the dispatch lambda for - # whichever handler produced one. The result type exists only in the 2026-07-28 stateless lifecycle, - # so a legacy request (no envelope) must not receive it: pre-2026 clients treat an unknown `resultType` as - # a final result. The capability gate enforces the SEP-2575 rule that servers MUST NOT rely on - # (or embed requests for) capabilities the client did not declare, and reports every missing capability at - # once so the client sees the full set. - def serialize_input_required_result(result, envelope:, request:, method:) - if envelope.nil? - raise RequestHandlerError.new( - "input_required results require the 2026-07-28 stateless lifecycle (SEP-2322)", - request, - error_type: :internal_error, - ) - end - - missing = result.missing_client_capabilities(envelope.client_capabilities) - raise MissingRequiredClientCapabilityError.new(missing, request) unless missing.empty? - - add_instrumentation_data(input_required: true) - serialized = result.to_h - - if @request_state_security && serialized[:requestState] - serialized = serialized.merge(requestState: @request_state_security.seal( - serialized[:requestState], - method: method, - target: mrtr_target(request), - arguments_digest: mrtr_arguments_digest(request), - )) - end - - serialized - end - - # Methods whose results may be `input_required` and whose retried requests carry - # `inputResponses`/`requestState` (SEP-2322). - MRTR_METHODS = [Methods::TOOLS_CALL, Methods::PROMPTS_GET, Methods::RESOURCES_READ].freeze - - # Fulfilment rounds the legacy shim runs before giving up, matching the TypeScript SDK's legacy shim default (`maxRounds: 8`). - LEGACY_INPUT_REQUIRED_MAX_ROUNDS = 8 - - # Dual-era authoring shim (SEP-2322): a handler on the legacy wire returned an `input_required` result, - # which pre-2026 clients cannot understand, so the server fulfills it in place of the client's driver. - # Every entry of `inputRequests` is sent as the equivalent real server-to-client request (associated with - # the originating request per SEP-2260), the answers are collected under the same keys, and the handler - # re-runs with `inputResponses`/`requestState` merged into the original params - the same deterministic replay - # contract the modern client driver follows. The `requestState` round-trips in-process as the raw value - # the handler wrote; `RequestStateSecurity` sealing is wire hardening and does not apply. - def run_legacy_input_required_shim(result, method:, params:, session:, related_request_id:, cancellation:) - rounds = 0 - - loop do - missing = result.missing_client_capabilities(session.client_capabilities) - unless missing.empty? - # The explicit `error_code` keeps the descriptive message in the JSON-RPC error response - # (the `ResourceNotFoundError` pattern). `-32021` is a 2026-07-28 code, so the legacy wire - # gets a plain internal error. - raise RequestHandlerError.new( - "input_required requires client capabilities the client did not declare: #{missing.to_json}", - params, - error_type: :internal_error, - error_code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - ) - end - - responses = (result.input_requests || {}).each_with_object({}) do |(key, entry), collected| - collected[key] = session.fulfill_input_request( - entry[:method], - legacy_leg_params(entry), - related_request_id: related_request_id, - ) - end - - retry_params = params.reject { |key, _| [:inputResponses, :requestState].include?(key.to_sym) } - retry_params[:inputResponses] = responses unless responses.empty? - retry_params[:requestState] = result.request_state if result.request_state - - result = redispatch_mrtr_method( - method, - retry_params, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - ) - return result unless result.is_a?(InputRequiredResult) - - rounds += 1 - next if rounds < LEGACY_INPUT_REQUIRED_MAX_ROUNDS - - raise RequestHandlerError.new( - "Handler still returned `input_required` after #{LEGACY_INPUT_REQUIRED_MAX_ROUNDS} legacy shim rounds (SEP-2322)", - params, - error_type: :internal_error, - error_code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - ) - end - end - - # The params an embedded entry sends on its legacy leg. Entries are forwarded verbatim with - # one exception: the 2025-11-25 wire requires `elicitationId` on URL-mode elicitation requests, - # a field the 2026-07-28 in-band shape dropped (correlation rides `requestState` there), - # so a missing one is synthesized for the leg, matching the TypeScript SDK's shim. - def legacy_leg_params(entry) - params = entry[:params] - return params unless entry[:method] == Methods::ELICITATION_CREATE - return params if params.nil? || (params[:mode] || params["mode"]) != "url" - return params if params.key?(:elicitationId) || params.key?("elicitationId") - - params.merge(elicitationId: SecureRandom.uuid) - end - - # Re-runs the handler of one of the three MRTR-capable methods for - # the legacy shim. Legacy wire, so no envelope is threaded. - def redispatch_mrtr_method(method, params, session:, related_request_id:, cancellation:) - case method - when Methods::TOOLS_CALL - call_tool(params, session: session, related_request_id: related_request_id, cancellation: cancellation) - when Methods::PROMPTS_GET - get_prompt(params, session: session, related_request_id: related_request_id, cancellation: cancellation) - when Methods::RESOURCES_READ - contents = read_resource_contents(params, session: session, related_request_id: related_request_id, cancellation: cancellation) - contents.is_a?(InputRequiredResult) ? contents : build_read_resource_result(contents) - else - raise RequestHandlerError.new( - "input_required results are only supported for #{MRTR_METHODS.join(", ")}", - params, - error_type: :internal_error, - ) - end - end - - # Replaces a sealed client-echoed `requestState` with its verified plaintext before dispatch, - # so handlers always read the state they wrote. A tampered, expired, or cross-request token is - # rejected as invalid params, matching the Python SDK's "Invalid or expired requestState" behavior. - def unseal_request_state(params, method:) - return params unless MRTR_METHODS.include?(method) - return params unless params.is_a?(Hash) - - sealed = params[:requestState] || params["requestState"] - return params unless sealed - - plaintext = @request_state_security.unseal( - sealed, - method: method, - target: mrtr_target(params), - arguments_digest: mrtr_arguments_digest(params), - ) - key = params.key?("requestState") ? "requestState" : :requestState - params.merge(key => plaintext) - rescue RequestStateSecurity::InvalidStateError => e - raise RequestHandlerError.new( - "Invalid or expired requestState", - params, - error_type: :invalid_params, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - original_error: e, - ) - end - - def mrtr_target(params) - return "" unless params.is_a?(Hash) - - params[:name] || params["name"] || params[:uri] || params["uri"] || "" - end - - # Digest of the originating arguments, binding a sealed state to retries of - # the same call with the same inputs. Keys are stringified and sorted recursively - # so symbol/string parses of identical JSON digest identically. - def mrtr_arguments_digest(params) - arguments = params.is_a?(Hash) ? params[:arguments] || params["arguments"] : nil - OpenSSL::Digest::SHA256.hexdigest(canonical_json(arguments || {})) - end - - def canonical_json(value) - case value - when Hash - pairs = value.map { |key, nested| [key.to_s, nested] }.sort_by(&:first) - "{#{pairs.map { |key, nested| "#{key.to_json}:#{canonical_json(nested)}" }.join(",")}}" - when Array - "[#{value.map { |element| canonical_json(element) }.join(",")}]" - else - value.to_json - end - end - - # Extracts the SEP-2322 retry fields a client sends when re-issuing a request: - # `inputResponses` (answers keyed like the earlier `inputRequests`) and the echoed opaque `requestState`. - # They are params-top-level siblings of `name`/`arguments`/ `uri`, not `_meta` entries. - def mrtr_retry_fields(params) - return { input_responses: nil, request_state: nil } unless params.is_a?(Hash) - - { - input_responses: params[:inputResponses] || params["inputResponses"], - request_state: params[:requestState] || params["requestState"], - } - end - - def handle_cancelled_notification(params, session: nil) - return unless session - return unless params.is_a?(Hash) - - request_id = params[:requestId] || params["requestId"] - return if request_id.nil? - - reason = params[:reason] || params["reason"] - session.cancel_incoming(request_id: request_id, reason: reason) - end - def default_capabilities { tools: { listChanged: true }, prompts: { listChanged: true }, resources: { listChanged: true }, - logging: {}, } end @@ -1059,178 +298,31 @@ module MCP }.compact end - def init(params, session: nil) - validate_initialize_params!(params) - - # MCP spec: the initialization phase MUST be the first interaction between client and server. - # Reject duplicate `initialize` on an already-initialized session so the negotiated - # client identity and capabilities cannot be silently overwritten. - if session&.initialized? - raise RequestHandlerError.new("Invalid Request: Server already initialized", params, error_type: :invalid_request) - end - - if session - session.store_client_info(client: params[:clientInfo], capabilities: params[:capabilities]) - else - @client = params[:clientInfo] - @client_capabilities = params[:capabilities] - end - protocol_version = params[:protocolVersion] - - # Per the SEP-2575 era model, `initialize` negotiates legacy protocol versions only: a modern version is - # defined by carrying its own version on every request in `_meta`, with no handshake, - # so asking `initialize` for one (or for a version this server does not know) is answered with - # a counter-offer instead of an echo, matching the TypeScript and Python SDKs. Modern versions - # stay reachable through `server/discover` and the per-request envelope. The counter-offer is - # a configured `protocol_version` pin when one is set (`Configuration` only accepts handshake versions there), - # and the latest handshake version otherwise. - negotiated_version = if Configuration.handshake_protocol_version?(protocol_version) - protocol_version - elsif configuration.protocol_version? - configuration.protocol_version - else - Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION - end - - info = server_info.reject do |property| - negotiated_version <= "2025-06-18" && UNSUPPORTED_PROPERTIES_UNTIL_2025_06_18.include?(property) || - negotiated_version <= "2025-03-26" && UNSUPPORTED_PROPERTIES_UNTIL_2025_03_26.include?(property) - end - - response_instructions = instructions - - if negotiated_version == "2024-11-05" - response_instructions = nil - end - - if session - session.mark_initialized!(protocol_version: negotiated_version) - else - @client_protocol_version = negotiated_version - end - + def init(request) { - protocolVersion: negotiated_version, + protocolVersion: configuration.protocol_version, capabilities: capabilities, - serverInfo: info, - instructions: response_instructions, + serverInfo: server_info, + instructions: instructions, }.compact end - def validate_resource_subscription_params!(params) - unless params.is_a?(Hash) && params[:uri].is_a?(String) - raise RequestHandlerError.new("Missing or invalid uri", params, error_type: :invalid_params) - end - end - - # The `resources/subscribe` and `resources/unsubscribe` result is an empty object except for the optional `_meta` - # every result may carry: the TypeScript SDK validates it against `EmptyResultSchema.strict()`, - # which rejects any other member, so only `_meta` is passed through from the handler. A handler that returns - # anything else keeps the empty `{}` result it had before, so returning a subscription identifier or - # other advisory data means nesting it under `_meta`. - def subscription_result(handler_result) - return {} unless handler_result.is_a?(Hash) - - meta = handler_result[:_meta] || handler_result["_meta"] - meta.is_a?(Hash) ? { _meta: meta } : {} - end - - def validate_initialize_params!(params) - unless params.is_a?(Hash) - raise RequestHandlerError.new("Invalid params", params, error_type: :invalid_params) - end - - unless params[:protocolVersion].is_a?(String) - raise RequestHandlerError.new("Missing or invalid protocolVersion", params, error_type: :invalid_params) - end - - unless params[:capabilities].is_a?(Hash) - raise RequestHandlerError.new("Missing or invalid capabilities", params, error_type: :invalid_params) - end - - client_info = params[:clientInfo] - if !client_info.is_a?(Hash) || client_info[:name].nil? || client_info[:version].nil? - raise RequestHandlerError.new("Missing or invalid clientInfo", params, error_type: :invalid_params) - end - end - - # Handles `server/discover` (MCP 2026-07-28, SEP-2575): sessionless capability discovery. - # Unlike `init`, this is state-free and idempotent: it stores no client info, does not mark - # the session initialized, and responds regardless of capability declarations or initialization state, - # so clients can probe a server before (or instead of) `initialize`. - # - # `supportedVersions` advertises modern versions only, matching the TypeScript and Python SDKs: - # legacy versions are negotiated via `initialize`, not selected from discovery. The `ttlMs`/`cacheScope` - # cache hints are REQUIRED on `DiscoverResult` (unlike the opt-in SEP-2549 hints on list/read results), - # so the spec defaults (`0` = immediately stale, `"private"` = per-authorization-context caching only) - # fill in when the server was not configured with `ttl_ms`/`cache_scope`. The server identity rides - # in the result `_meta` as the optional `io.modelcontextprotocol/serverInfo` stamp per the finalized - # spec (PR #3002), unfiltered because discovery happens before version negotiation. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2575 - def discover(_request) - { - supportedVersions: Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, - capabilities: discover_capabilities, - instructions: instructions, - _meta: { RequestEnvelope::SERVER_INFO_META_KEY => server_info }, - }.compact.merge( - ttlMs: ttl_ms || 0, - cacheScope: cache_scope || "private", - # `server/discover` is exempt from the `_meta` envelope, so the central modern-result stamping does not see it; - # `DiscoverResult` is still a 2026-07-28 result and carries the REQUIRED `resultType` directly. - resultType: ResultType::COMPLETE, - ) - end - - # Capabilities as advertised by `server/discover`. In the modern lifecycle, `listChanged` and `subscribe` flags - # promise delivery over `subscriptions/listen` streams, so they are stripped when the transport does not serve that RPC - # (e.g. stdio), matching the Python SDK's era-aware capability derivation. - def discover_capabilities - return capabilities if @transport.respond_to?(:serves_subscriptions_listen?) && @transport.serves_subscriptions_listen? - - capabilities.each_with_object({}) do |(name, value), stripped| - stripped[name] = if value.is_a?(Hash) - value.reject { |flag, _| ["listChanged", "subscribe"].include?(flag.to_s) } - else - value - end - end - end - - def configure_logging_level(request, session: nil) - if capabilities[:logging].nil? - raise RequestHandlerError.new("Server does not support logging", request, error_type: :internal_error) - end - - logging_message_notification = LoggingMessageNotification.new(level: request[:level]) - unless logging_message_notification.valid_level? - raise RequestHandlerError.new("Invalid log level #{request[:level]}", request, error_type: :invalid_params) - end - - session&.configure_logging(logging_message_notification) - @logging_message_notification = logging_message_notification - - {} - end - def list_tools(request) - page = paginate(@tools.values, cursor: cursor_from(request), page_size: @page_size, request: request, &:to_h) - - apply_cache_metadata({ tools: page[:items], nextCursor: page[:next_cursor] }.compact) + @tools.values.map(&:to_h) end - def call_tool(request, session: nil, related_request_id: nil, cancellation: nil, envelope: nil) + def call_tool(request) tool_name = request[:name] tool = tools[tool_name] unless tool add_instrumentation_data(tool_name: tool_name, error: :tool_not_found) - raise RequestHandlerError.new("Tool not found: #{tool_name}", request, error_type: :invalid_params) + return error_tool_response("Tool not found: #{tool_name}") end arguments = request[:arguments] || {} - add_instrumentation_data(tool_name: tool_name, tool_arguments: arguments) + add_instrumentation_data(tool_name: tool_name) if tool.input_schema&.missing_required_arguments?(arguments) add_instrumentation_data(error: :missing_required_arguments) @@ -1249,67 +341,23 @@ module MCP end end - progress_token = request.dig(:_meta, :progressToken) - - response = call_tool_with_args( - tool, - arguments, - server_context_with_meta(request), - progress_token: progress_token, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - retry_fields: mrtr_retry_fields(request), - ) - # An SEP-2322 `input_required` result is not a tool result: output schema - # validation would run against a `nil` `structuredContent` and the structured - # content fallback does not apply. The dispatch lambda serializes it. - return response if response.is_a?(InputRequiredResult) - - result = response.to_h - validate_tool_call_result!(tool, result) - serialize_structured_content_fallback( - result, - content_provided: response.respond_to?(:content_provided?) && response.content_provided?, - ) - rescue RequestHandlerError, CancelledError - # CancelledError is intentionally not wrapped so `handle_request` can turn it into - # `JsonRpcHandler::NO_RESPONSE` per the MCP cancellation spec. - raise + call_tool_with_args(tool, arguments) rescue => e - # `e.message` is deliberately not included: it can carry internals (class, method - # and host names) that must not reach untrusted clients (CWE-209). The original - # exception still reaches `configuration.exception_reporter` via `original_error`. - raise RequestHandlerError.new( - "Internal error calling tool #{tool_name}", - request, - error_type: :internal_error, - original_error: e, - ) + report_exception(e, request: request) + + error_tool_response("Internal error calling tool #{tool_name}: #{e.message}") end def list_prompts(request) - page = paginate(@prompts.values, cursor: cursor_from(request), page_size: @page_size, request: request, &:to_h) - - apply_cache_metadata({ prompts: page[:items], nextCursor: page[:next_cursor] }.compact) + @prompts.values.map(&:to_h) end - def get_prompt(request, session: nil, related_request_id: nil, cancellation: nil, envelope: nil) + def get_prompt(request) prompt_name = request[:name] prompt = @prompts[prompt_name] unless prompt add_instrumentation_data(error: :prompt_not_found) - # The explicit `error_code` maps an unknown prompt to Invalid Params (-32602) rather than - # the default Internal Error (-32603), matching the `tools/call`, `resources/read`, and - # `completion/complete` siblings for the same not-found condition, while `error_type: - # :prompt_not_found` keeps the descriptive message and instrumentation label. - raise RequestHandlerError.new( - "Prompt not found #{prompt_name}", - request, - error_type: :prompt_not_found, - error_code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - ) + raise RequestHandlerError.new("Prompt not found #{prompt_name}", request, error_type: :prompt_not_found) end add_instrumentation_data(prompt_name: prompt_name) @@ -1317,205 +365,21 @@ module MCP prompt_args = request[:arguments] prompt.validate_arguments!(prompt_args) - server_context = build_server_context( - request: request, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - ) - - call_prompt_template_with_args(prompt, prompt_args, server_context) + call_prompt_template_with_args(prompt, prompt_args) end - def list_resources(request, server_context: nil) - resources = if @resources_list_handler - invoke_resources_list_handler(request, server_context) - else - @resources - end - - page = paginate(resources, cursor: cursor_from(request), page_size: @page_size, request: request, &:to_h) - - apply_cache_metadata({ resources: page[:items], nextCursor: page[:next_cursor] }.compact) + def list_resources(request) + @resources.map(&:to_h) end - # Calls the `resources_list_handler` block, forwarding `server_context:` only when the block opts in - # by declaring the keyword (the same rule `dispatch_optional_context_handler` applies). - def invoke_resources_list_handler(request, server_context) - if handler_declares_server_context?(@resources_list_handler) - @resources_list_handler.call(request, server_context: server_context) - else - @resources_list_handler.call(request) - end - end - - # Default `resources/read` handler: routes to class-based resources and resource templates. - # Fully replaced when `resources_read_handler` is set. When no class-based resource or template is registered, - # unknown URIs keep the historical no-op `[]` response instead of raising. - def read_resource(request, server_context: nil) - uri = request[:uri] - add_instrumentation_data(resource_uri: uri) - - resource = @resource_index[uri] - if resource.is_a?(Class) - return normalize_resource_contents(call_resource_contents(resource, server_context)) - end - - @resource_templates.each do |template| - next unless template.is_a?(Class) - - params = template.match_uri(uri) - next unless params - - add_instrumentation_data(resource_template: template.uri_template) - return normalize_resource_contents(call_template_contents(template, params, server_context)) - end - - return [] unless class_based_resources_registered? - - raise ResourceNotFoundError.new(uri, request) - end - - def call_resource_contents(resource, server_context) - if accepts_server_context?(resource.method(:contents)) - resource.contents(server_context: server_context) - else - resource.contents - end - end - - def call_template_contents(template, params, server_context) - if accepts_server_context?(template.method(:contents)) - template.contents(**params, server_context: server_context) - else - template.contents(**params) - end - end - - def normalize_resource_contents(result) - contents = result.is_a?(Array) ? result : [result] - contents.map(&:to_h) - end - - def class_based_resources_registered? - @resources.any? { |resource| resource.is_a?(Class) } || - @resource_templates.any? { |template| template.is_a?(Class) } + # Server implementation should set `resources_read_handler` to override no-op default + def read_resource_no_content(request) + add_instrumentation_data(resource_uri: request[:uri]) + [] end def list_resource_templates(request) - page = paginate(@resource_templates, cursor: cursor_from(request), page_size: @page_size, request: request, &:to_h) - - apply_cache_metadata({ resourceTemplates: page[:items], nextCursor: page[:next_cursor] }.compact) - end - - # Builds the `resources/read` result. The documented handler contract is "return value becomes `contents`"; - # a Hash with a `:contents` key is also accepted as a full result so a handler can override the server-level - # `ttlMs`/`cacheScope` cache hints per result (SEP-2549). - def build_read_resource_result(handler_result) - result = if handler_result.is_a?(Hash) && handler_result.key?(:contents) - handler_result - else - { contents: handler_result } - end - - apply_cache_metadata(result) - end - - # Adds the SEP-2549 cache hints (`ttlMs`, `cacheScope`) to a result. Emission is opt-in: nothing is added - # unless the server was configured with `ttl_ms`/`cache_scope` or the result already carries one of the fields, - # in which case the missing one is filled with `ttlMs: 0` (do not cache) or `cacheScope: "private"`, - # the side that cannot leak a user-dependent result through a shared cache (the TypeScript SDK's default). - # Values already in the result win, enabling per-result overrides. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2549 - def apply_cache_metadata(result) - explicit = result.key?(:ttlMs) || result.key?(:cacheScope) - return result if @ttl_ms.nil? && @cache_scope.nil? && !explicit - - { ttlMs: @ttl_ms || 0, cacheScope: @cache_scope || "private" }.merge(result) - end - - def complete(params, session: nil, related_request_id: nil, cancellation: nil, envelope: nil) - validate_completion_params!(params) - - result = dispatch_optional_context_handler( - @handlers[Methods::COMPLETION_COMPLETE], - params, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - ) - - normalize_completion_result(result) - end - - # Invokes `resources/read` via the registered handler. If the handler block opts in to `server_context:`, - # pass an `MCP::ServerContext` so the handler can observe cancellation via `server_context.cancelled?` or - # `server_context.raise_if_cancelled!`. - def read_resource_contents(request, session: nil, related_request_id: nil, cancellation: nil, envelope: nil) - dispatch_optional_context_handler( - @handlers[Methods::RESOURCES_READ], - request, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - ) - end - - # Opt-in `server_context:` dispatch for block-based handlers registered via `resources_read_handler`, - # `completion_handler`, `resources_subscribe_handler`, `resources_unsubscribe_handler`, or `define_custom_method`. - # Existing handlers that only accept `params` are called unchanged; handlers that declare a `server_context:` - # keyword receive an `MCP::ServerContext` wrapping the raw server context with cancellation plumbing. - def dispatch_optional_context_handler(handler, params, session: nil, related_request_id: nil, cancellation: nil, envelope: nil) - return handler.call(params) unless handler_declares_server_context?(handler) - - server_context = build_server_context( - request: params, - session: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - ) - handler.call(params, server_context: server_context) - end - - # Stricter than `accepts_server_context?`: requires `server_context` to appear as a named keyword parameter - # (`:key` optional, `:keyreq` required). Positional parameters named `server_context` (`:req` / `:opt`) are NOT - # treated as opt-in - otherwise `handler.call(params, server_context: ctx)` would pass the `{server_context: ctx}` - # Hash as the handler's second positional argument, which is never what the user meant. - # - # `**kwargs`-only signatures (`:keyrest` without a named `server_context`) are also not opt-in here, - # because the dispatch site passes a positional `params`, and a `**kwargs`-only block cannot accept - # that positional argument (lambdas/methods raise `ArgumentError`; non-lambda procs silently drop `params`). - # Tool handlers intentionally allow `**kwargs` opt-in via `accepts_server_context?` because they are invoked - # via `tool.call(**args, server_context: …)` without a positional argument. - def handler_declares_server_context?(handler) - return false unless handler.respond_to?(:parameters) - - handler.parameters.any? do |type, name| - name == :server_context && (type == :key || type == :keyreq) - end - end - - # Builds an `MCP::ServerContext` used to give a handler access to session-scoped helpers - # (progress, cancellation, nested server-to-client requests). - def build_server_context(request:, session:, related_request_id:, cancellation:, envelope: nil) - meta_source = request.is_a?(Hash) ? request : {} - progress_token = meta_source.dig(:_meta, :progressToken) - progress = Progress.new(notification_target: session, progress_token: progress_token, related_request_id: related_request_id) - retry_fields = mrtr_retry_fields(meta_source) - ServerContext.new( - server_context_with_meta(meta_source), - progress: progress, - notification_target: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - input_responses: retry_fields[:input_responses], - request_state: retry_fields[:request_state], - ) + @resource_templates.map(&:to_h) end def report_exception(exception, server_context = {}) @@ -1523,7 +387,9 @@ module MCP end def index_resources_by_uri(resources) - resources.to_h { |resource| [resource.uri, resource] } + resources.each_with_object({}) do |resource, hash| + hash[resource.uri] = resource + end end def error_tool_response(text) @@ -1536,141 +402,28 @@ module MCP ).to_h end - def validate_tool_call_result!(tool, result) - return unless configuration.validate_tool_call_results - return unless tool.output_schema - return if result[:isError] - - tool.output_schema.validate_result(result[:structuredContent]) - end - - # Per SEP-2106, `structuredContent` may be any JSON value, not only an object. - # Clients on older protocol versions may only read `content`, - # so when a tool returns non-object structured content without explicitly - # providing `content`, mirror the value into serialized JSON text. - def serialize_structured_content_fallback(result, content_provided: false) - structured = result[:structuredContent] - return result if structured.nil? || structured.is_a?(Hash) - return result if content_provided - return result unless result[:content].nil? || result[:content].empty? - - serialized = JSON.generate(structured) - return result if JSON.parse(serialized).is_a?(Hash) - - result.merge(content: [{ type: "text", text: serialized }]) - end - - # Whether a tool/prompt handler opts in to receiving an `MCP::ServerContext`. - # Recognizes `:keyrest` (`**kwargs`) because tools are invoked without a positional argument - # (`tool.call(**args, server_context:)`), soa `**kwargs`-only signature safely captures `server_context:`. - # Named keyword `server_context` must be `:key` or `:keyreq` - positional parameters (`:req` / `:opt`) that - # happen to be named `server_context` are excluded because the call site passes `server_context:` as a keyword, - # and a positional slot would receive the `{server_context: ctx}` Hash instead. def accepts_server_context?(method_object) parameters = method_object.parameters - parameters.any? do |type, name| - type == :keyrest || (name == :server_context && (type == :key || type == :keyreq)) - end + parameters.any? { |type, name| type == :keyrest || name == :server_context } end - def call_tool_with_args(tool, arguments, context, progress_token: nil, session: nil, related_request_id: nil, cancellation: nil, envelope: nil, retry_fields: nil) - # Transports parse incoming JSON with `symbolize_names: true`, so `arguments` already arrives symbolized - # at every nesting level. This top-level transform only guards callers that hand in string-keyed top-level arguments; - # it does not recurse, and nested object keys remain symbols. Tools therefore receive symbol keys all the way down. - # See docs/server/tools.md ("Tool argument keys"). + def call_tool_with_args(tool, arguments) args = arguments&.transform_keys(&:to_sym) || {} if accepts_server_context?(tool.method(:call)) - progress = Progress.new(notification_target: session, progress_token: progress_token, related_request_id: related_request_id) - server_context = ServerContext.new( - context, - progress: progress, - notification_target: session, - related_request_id: related_request_id, - cancellation: cancellation, - envelope: envelope, - input_responses: retry_fields&.fetch(:input_responses, nil), - request_state: retry_fields&.fetch(:request_state, nil), - ) - tool.call(**args, server_context: server_context) + tool.call(**args, server_context: server_context).to_h else - tool.call(**args) + tool.call(**args).to_h end end - def call_prompt_template_with_args(prompt, args, server_context) - raw_result = if accepts_server_context?(prompt.method(:template)) - prompt.template(args, server_context: server_context) + def call_prompt_template_with_args(prompt, args) + if accepts_server_context?(prompt.method(:template)) + prompt.template(args, server_context: server_context).to_h else - prompt.template(args) + prompt.template(args).to_h end - - raw_result.is_a?(InputRequiredResult) ? raw_result : raw_result.to_h - end - - def server_context_with_meta(request) - meta = request[:_meta] - if meta && server_context.is_a?(Hash) - context = server_context.dup - context[:_meta] = meta - context - elsif meta && server_context.nil? - { _meta: meta } - else - server_context - end - end - - def validate_completion_params!(params) - unless params.is_a?(Hash) - raise RequestHandlerError.new("Invalid params", params, error_type: :invalid_params) - end - - ref = params[:ref] - if ref.nil? || ref[:type].nil? - raise RequestHandlerError.new("Missing or invalid ref", params, error_type: :invalid_params) - end - - argument = params[:argument] - if argument.nil? || argument[:name].nil? || !argument.key?(:value) - raise RequestHandlerError.new("Missing argument name or value", params, error_type: :invalid_params) - end - - case ref[:type] - when "ref/prompt" - unless @prompts[ref[:name]] - raise RequestHandlerError.new("Prompt not found: #{ref[:name]}", params, error_type: :invalid_params) - end - when "ref/resource" - uri = ref[:uri] - found = @resource_index.key?(uri) || @resource_templates.any? { |t| t.uri_template == uri } - unless found - raise ResourceNotFoundError.new(uri, params) - end - else - raise RequestHandlerError.new("Invalid ref type: #{ref[:type]}", params, error_type: :invalid_params) - end - end - - def normalize_completion_result(result) - return DEFAULT_COMPLETION_RESULT unless result.is_a?(Hash) - - completion = result[:completion] || result["completion"] - return DEFAULT_COMPLETION_RESULT unless completion.is_a?(Hash) - - values = completion[:values] || completion["values"] || [] - total = completion[:total] || completion["total"] - has_more = completion[:hasMore] || completion["hasMore"] || false - - count = values.length - if count > MAX_COMPLETION_VALUES - has_more = true - total ||= count - values = values.first(MAX_COMPLETION_VALUES) - end - - { completion: { values: values, total: total, hasMore: has_more }.compact } end end end diff --git a/lib/mcp/server/capabilities.rb b/lib/mcp/server/capabilities.rb index 0efe015..6647eb9 100644 --- a/lib/mcp/server/capabilities.rb +++ b/lib/mcp/server/capabilities.rb @@ -6,7 +6,6 @@ module MCP def initialize(capabilities_hash = nil) @completions = nil @experimental = nil - @extensions = nil @logging = nil @prompts = nil @resources = nil @@ -15,7 +14,6 @@ module MCP if capabilities_hash support_completions if capabilities_hash.key?(:completions) support_experimental(capabilities_hash[:experimental]) if capabilities_hash.key?(:experimental) - support_extensions(capabilities_hash[:extensions]) if capabilities_hash.key?(:extensions) support_logging if capabilities_hash.key?(:logging) if capabilities_hash.key?(:prompts) @@ -47,17 +45,6 @@ module MCP @experimental = config || {} end - # Declares support for capability extensions per SEP-2133. Keys are - # extension identifiers using the reverse-DNS prefix convention - # (e.g. `"io.modelcontextprotocol/tasks"`, `"com.example/feature"`); - # values are arbitrary extension-defined configuration objects, - # with an empty hash meaning "supported with no settings". - # Repeated calls merge, so several extensions can be declared independently. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2133 - def support_extensions(extensions = {}) - @extensions = (@extensions || {}).merge(extensions || {}) - end - def support_logging @logging ||= {} end @@ -98,7 +85,6 @@ module MCP { completions: @completions, experimental: @experimental, - extensions: @extensions, logging: @logging, prompts: @prompts, resources: @resources, diff --git a/lib/mcp/server/input_required_result.rb b/lib/mcp/server/input_required_result.rb deleted file mode 100644 index 16242e7..0000000 --- a/lib/mcp/server/input_required_result.rb +++ /dev/null @@ -1,163 +0,0 @@ -# frozen_string_literal: true - -require_relative "../methods" -require_relative "../result_type" - -module MCP - class Server - # A multi round-trip `input_required` result (SEP-2322, MCP 2026-07-28). - # Handlers for `tools/call`, `prompts/get`, and `resources/read` may return one instead of - # their normal result to ask the client for additional input: `input_requests` maps server-assigned keys - # to embedded request shapes (`elicitation/create`, `sampling/createMessage`, or `roots/list`), - # and `request_state` is an opaque continuation string the client echoes back byte-exactly when it retries - # the original request with `inputResponses` under the same keys. - # - # The server holds no memory between rounds: handlers re-run from the start on every retry and read - # the answers via `server_context.input_responses` / `server_context.request_state` - # (deterministic replay, matching the Python SDK). At least one of the two fields must be present; - # a `request_state`-only result is the load-shedding form ("retry later"). - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2322 - class InputRequiredResult - EMBEDDABLE_METHODS = [ - Methods::ELICITATION_CREATE, - Methods::SAMPLING_CREATE_MESSAGE, - Methods::ROOTS_LIST, - ].freeze - - attr_reader :input_requests, :request_state - - def initialize(input_requests: nil, request_state: nil) - if (input_requests.nil? || input_requests.empty?) && request_state.nil? - raise ArgumentError, "at least one of input_requests or request_state is required" - end - unless request_state.nil? || request_state.is_a?(String) - raise ArgumentError, "request_state must be a String" - end - - @input_requests = normalize_input_requests(input_requests) - @request_state = request_state - freeze - end - - def to_h - serialized_requests = @input_requests&.transform_values do |entry| - { method: entry[:method], params: entry[:params] }.compact - end - - { - resultType: ResultType::INPUT_REQUIRED, - inputRequests: serialized_requests, - requestState: @request_state, - }.compact - end - - # The client capabilities required to fulfill every embedded request, merged into one nested hash. - # The mapping matches the TypeScript SDK's `requiredClientCapabilitiesForInputRequest`: - # `elicitation/create` with `mode: "url"` requires `elicitation.url`, any other `elicitation/create` - # requires `elicitation.form`, `sampling/createMessage` with `tools`/`toolChoice` requires `sampling.tools` - # (plain sampling otherwise), and `roots/list` requires `roots`. - def required_client_capabilities - (@input_requests || {}).values.reduce({}) do |merged, entry| - deep_merge(merged, entry_capability(entry)) - end - end - - # The subset of {#required_client_capabilities} the request did not declare. - # Per SEP-2575, servers MUST NOT rely on capabilities the client has not declared, - # so a non-empty return means the result must not be sent (`-32021`). - def missing_client_capabilities(declared) - missing = missing_subtree(required_client_capabilities, declared) - prune_implied_form_elicitation(missing, declared) - end - - private - - def normalize_input_requests(input_requests) - return if input_requests.nil? - - raise ArgumentError, "input_requests must be a Hash" unless input_requests.is_a?(Hash) - - normalized = input_requests.each_with_object({}) do |(key, entry), result| - raise ArgumentError, "input_requests entries must be Hashes" unless entry.is_a?(Hash) - - method = entry[:method] || entry["method"] - unless EMBEDDABLE_METHODS.include?(method) - raise ArgumentError, - "input_requests entry #{key.inspect} must have a method of " \ - "#{EMBEDDABLE_METHODS.join(", ")} (got #{method.inspect})" - end - - params = entry[:params] || entry["params"] - raise ArgumentError, "input_requests entry params must be a Hash" unless params.nil? || params.is_a?(Hash) - - result[key.to_s] = { method: method, params: params }.compact.freeze - end - - normalized.freeze - end - - def entry_capability(entry) - params = entry[:params] - - case entry[:method] - when Methods::ELICITATION_CREATE - mode = params && (params[:mode] || params["mode"]) - mode == "url" ? { elicitation: { url: {} } } : { elicitation: { form: {} } } - when Methods::SAMPLING_CREATE_MESSAGE - with_tools = params && (params.key?(:tools) || params.key?("tools") || - params.key?(:toolChoice) || params.key?("toolChoice")) - with_tools ? { sampling: { tools: {} } } : { sampling: {} } - when Methods::ROOTS_LIST - { roots: {} } - end - end - - # Walks `required` and keeps only the branches absent from `declared` - # (symbol/string tolerant on the declared side). - def missing_subtree(required, declared) - required.each_with_object({}) do |(name, nested), missing| - declared_value = read_key(declared, name) - - if declared_value.nil? - missing[name] = nested - elsif nested.is_a?(Hash) && !nested.empty? - nested_missing = missing_subtree(nested, declared_value) - missing[name] = nested_missing unless nested_missing.empty? - end - end - end - - # 2025 back-compat implication shared with the TypeScript and Python SDKs: - # a bare `elicitation: {}` declaration implies form elicitation support, while - # an explicit url-only declaration does not. - def prune_implied_form_elicitation(missing, declared) - elicitation_missing = missing[:elicitation] - return missing unless elicitation_missing.is_a?(Hash) && elicitation_missing.key?(:form) - - declared_elicitation = read_key(declared, :elicitation) - return missing unless declared_elicitation.is_a?(Hash) - return missing unless read_key(declared_elicitation, :url).nil? - - pruned = elicitation_missing.reject { |key, _| key == :form } - pruned.empty? ? missing.reject { |key, _| key == :elicitation } : missing.merge(elicitation: pruned) - end - - def read_key(hash, key) - return unless hash.is_a?(Hash) - - value = hash[key.to_sym] - value.nil? ? hash[key.to_s] : value - end - - def deep_merge(left, right) - left.merge(right) do |_key, left_value, right_value| - if left_value.is_a?(Hash) && right_value.is_a?(Hash) - deep_merge(left_value, right_value) - else - right_value - end - end - end - end - end -end diff --git a/lib/mcp/server/pagination.rb b/lib/mcp/server/pagination.rb deleted file mode 100644 index aa26b21..0000000 --- a/lib/mcp/server/pagination.rb +++ /dev/null @@ -1,42 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Server - module Pagination - private - - def cursor_from(request) - return if request.nil? - - unless request.is_a?(Hash) - raise RequestHandlerError.new("Invalid params", request, error_type: :invalid_params) - end - - request[:cursor] - end - - def paginate(items, cursor:, page_size:, request:, &block) - start_index = 0 - - if cursor - unless cursor.is_a?(String) - raise RequestHandlerError.new("Invalid cursor", request, error_type: :invalid_params) - end - - start_index = Integer(cursor, exception: false) - if start_index.nil? || start_index < 0 || start_index >= items.size - raise RequestHandlerError.new("Invalid cursor", request, error_type: :invalid_params) - end - end - - end_index = page_size ? start_index + page_size : items.size - page = items[start_index...end_index] - page = page.map(&block) if block - - result = { items: page } - result[:next_cursor] = end_index.to_s if end_index < items.size - result - end - end - end -end diff --git a/lib/mcp/server/pending_response.rb b/lib/mcp/server/pending_response.rb deleted file mode 100644 index a82ae07..0000000 --- a/lib/mcp/server/pending_response.rb +++ /dev/null @@ -1,62 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Server - # A one-shot, timeout-aware handoff between the thread awaiting a server-to-client response - # and whichever thread resolves it (the client's response, a cancellation, or session teardown). - # - # `Queue#pop` only accepts a `timeout:` on Ruby 3.2 and later, and this gem supports 2.7, - # so the wait is expressed with a `ConditionVariable`. The `push`/`pop` names mirror the `Queue` - # this replaces, keeping the resolving call sites unchanged. - # - # First writer wins: a second `push` is ignored, so a cancellation that races a real response - # cannot overwrite it. `pop` returns the pushed value, or the `on_timeout` result when - # the deadline passes with nothing pushed. - class PendingResponse - def initialize - @mutex = Mutex.new - @condition = ConditionVariable.new - @delivered = false - @value = nil - end - - # Resolves the wait. Ignored when a value was already delivered. - def push(value) - @mutex.synchronize do - next if @delivered - - @delivered = true - @value = value - @condition.broadcast - end - end - - # Blocks until a value is pushed or `timeout` seconds elapse, and yields to the caller - # on expiry so it can decide what a timeout means. `ConditionVariable#wait` can return spuriously, - # so the deadline is re-checked against the monotonic clock. - # - # The expiry block runs after the lock is released: it typically cancels the request, - # which resolves this same object, and Ruby's `Mutex` is not reentrant. - def pop(timeout:) - deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + timeout - expired = false - - value = @mutex.synchronize do - until @delivered - remaining = deadline - Process.clock_gettime(Process::CLOCK_MONOTONIC) - if remaining <= 0 - expired = true - break - end - - @condition.wait(@mutex, remaining) - end - - @value - end - - expired ? yield : value - end - end - end -end diff --git a/lib/mcp/server/request_state_security.rb b/lib/mcp/server/request_state_security.rb deleted file mode 100644 index bc96a85..0000000 --- a/lib/mcp/server/request_state_security.rb +++ /dev/null @@ -1,131 +0,0 @@ -# frozen_string_literal: true - -require "json" -require "openssl" - -module MCP - class Server - # Opt-in protection for the SEP-2322 `requestState` echo. The opaque continuation string leaves the server, - # sits in the client's hands, and comes back as client-controlled input, so it must be treated like - # any other untrusted data. Sealing encrypts the state with AES-256-GCM (clients cannot read it) and binds - # a claims envelope that unsealing verifies fail-closed: - # - # - `exp`: a TTL window (re-sealed each round) - # - `m` / `t`: the originating method and target (tool/prompt name or resource URI) - # - `a`: a digest of the originating arguments, so the state only resumes the same call with the same inputs - # - `aud`: an optional audience, so tokens cannot cross servers sharing a key - # - # Pass an instance via `Server.new(request_state_security:)` and the seal/unseal happens transparently; - # handlers keep reading plaintext through `server_context.request_state`. Without it, the state crosses - # the wire exactly as the handler wrote it (the author's responsibility, matching the Python SDK's low-level Server). - # The key must be shared across workers in multi-process - # - # deployments; a per-process random key makes retries that land on another worker fail with an invalid-state error, - # forcing clients to restart the flow. - # - # The token format is `v1.`, with the version prefix bound as GCM associated data, - # following the Python SDK's `AESGCMRequestStateCodec`. - class RequestStateSecurity - class InvalidStateError < StandardError; end - - VERSION_PREFIX = "v1." - KEY_BYTES = 32 - IV_BYTES = 12 - TAG_BYTES = 16 - DEFAULT_TTL = 300 - - def initialize(key:, ttl: DEFAULT_TTL, audience: nil) - unless key.is_a?(String) && key.bytesize == KEY_BYTES - raise ArgumentError, "key must be a #{KEY_BYTES}-byte String" - end - unless ttl.is_a?(Numeric) && ttl.positive? - raise ArgumentError, "ttl must be a positive number of seconds" - end - - @key = key.dup.force_encoding(Encoding::BINARY).freeze - @ttl = ttl - @audience = audience - end - - # Seals a plaintext state into an opaque token bound to the originating request. - def seal(state, method:, target:, arguments_digest:) - claims = { - v: 1, - exp: Time.now.to_i + @ttl, - m: method, - t: target, - a: arguments_digest, - aud: @audience, - s: state, - }.compact - - cipher = OpenSSL::Cipher.new("aes-256-gcm").encrypt - cipher.key = @key - iv = cipher.random_iv - cipher.auth_data = VERSION_PREFIX - ciphertext = cipher.update(JSON.generate(claims)) + cipher.final - - VERSION_PREFIX + base64url_encode(iv + ciphertext + cipher.auth_tag) - end - - # Unseals a client-echoed token and verifies every claim, failing closed with - # `InvalidStateError` on tampering, expiry, or a claims mismatch. - def unseal(sealed, method:, target:, arguments_digest:) - unless sealed.is_a?(String) && sealed.start_with?(VERSION_PREFIX) - raise InvalidStateError, "malformed token" - end - - blob = base64url_decode(sealed.delete_prefix(VERSION_PREFIX)) - raise InvalidStateError, "malformed token" if blob.bytesize < IV_BYTES + TAG_BYTES - - iv = blob.byteslice(0, IV_BYTES) - tag = blob.byteslice(-TAG_BYTES, TAG_BYTES) - ciphertext = blob.byteslice(IV_BYTES, blob.bytesize - IV_BYTES - TAG_BYTES) - - cipher = OpenSSL::Cipher.new("aes-256-gcm").decrypt - cipher.key = @key - cipher.iv = iv - cipher.auth_tag = tag - cipher.auth_data = VERSION_PREFIX - plaintext = begin - cipher.update(ciphertext) + cipher.final - rescue OpenSSL::Cipher::CipherError - raise InvalidStateError, "authentication failed" - end - - claims = begin - JSON.parse(plaintext, symbolize_names: true) - rescue JSON::ParserError - raise InvalidStateError, "malformed claims" - end - - verify!(claims, method: method, target: target, arguments_digest: arguments_digest) - claims[:s] - end - - private - - def verify!(claims, method:, target:, arguments_digest:) - raise InvalidStateError, "unsupported version" unless claims[:v] == 1 - raise InvalidStateError, "expired" unless claims[:exp].is_a?(Integer) && Time.now.to_i <= claims[:exp] - raise InvalidStateError, "method mismatch" unless claims[:m] == method - raise InvalidStateError, "target mismatch" unless claims[:t] == target - raise InvalidStateError, "arguments mismatch" unless claims[:a] == arguments_digest - raise InvalidStateError, "audience mismatch" unless claims[:aud] == @audience - raise InvalidStateError, "missing state" unless claims[:s].is_a?(String) - end - - def base64url_encode(data) - [data].pack("m0").tr("+/", "-_").delete("=") - end - - def base64url_decode(encoded) - padded = encoded.tr("-_", "+/") - padded += "=" * ((4 - padded.length % 4) % 4) - padded.unpack1("m0") - rescue ArgumentError - raise InvalidStateError, "malformed token" - end - end - end -end diff --git a/lib/mcp/server/transports.rb b/lib/mcp/server/transports.rb deleted file mode 100644 index 1c4bc1c..0000000 --- a/lib/mcp/server/transports.rb +++ /dev/null @@ -1,10 +0,0 @@ -# frozen_string_literal: true - -module MCP - class Server - module Transports - autoload :StdioTransport, "mcp/server/transports/stdio_transport" - autoload :StreamableHTTPTransport, "mcp/server/transports/streamable_http_transport" - end - end -end diff --git a/lib/mcp/server/transports/stdio_transport.rb b/lib/mcp/server/transports/stdio_transport.rb index 8c75812..702af08 100644 --- a/lib/mcp/server/transports/stdio_transport.rb +++ b/lib/mcp/server/transports/stdio_transport.rb @@ -1,7 +1,7 @@ # frozen_string_literal: true -require "json" require_relative "../../transport" +require "json" module MCP class Server @@ -9,50 +9,18 @@ module MCP class StdioTransport < Transport STATUS_INTERRUPTED = Signal.list["INT"] + 128 - # Default upper bound on a single newline-delimited frame. CRuby's `IO#gets` - # without a limit accumulates bytes until a newline arrives, so a peer that - # never emits one can grow a single String until the process is OOM-killed. - # 4 MiB is large enough for any realistic JSON-RPC frame, including - # base64-embedded images. - MAX_LINE_BYTES = 4 * 1024 * 1024 - - def initialize(server, max_line_bytes: MAX_LINE_BYTES) - super(server) + def initialize(server) + @server = server @open = false - @session = nil - # Reject `nil` or non-positive values: `IO#gets("\n", nil)` and a negative - # limit read without an upper bound, which would silently disable the - # protection this option exists to provide. - unless max_line_bytes.is_a?(Integer) && max_line_bytes > 0 - raise ArgumentError, "max_line_bytes must be a positive Integer" - end - - @max_line_bytes = max_line_bytes $stdin.set_encoding("UTF-8") $stdout.set_encoding("UTF-8") + super end def open @open = true - @session = ServerSession.new(server: @server, transport: self) - while @open - begin - line = read_line($stdin) - rescue RequestHandlerError => e - # Stop accumulating and end the connection gracefully rather than - # letting an unbounded read exhaust memory or escape as an uncaught - # backtrace. Scoped to the read so genuine request errors raised while - # handling a frame are not swallowed here. - @open = false - MCP.configuration.exception_reporter.call(e, { error: "stdio frame exceeds limit" }) - break - end - break if line.nil? - - line = line.strip - parsed = parse_line(line) - response = parsed ? dispatch_with_era(parsed) : @session.handle_json(line) - send_response(response) if response + while @open && (line = $stdin.gets) + handle_json_request(line.strip) end rescue Interrupt warn("\nExiting...") @@ -83,103 +51,6 @@ module MCP MCP.configuration.exception_reporter.call(e, { error: "Failed to send notification" }) false end - - # NOTE: This signature deliberately matches the abstract `Transport#send_request` contract - # (`method, params = nil`) without the cancellation kwargs that `StreamableHTTPTransport#send_request` accepts. - # On Ruby 2.7 the project's supported minimum a method that mixes a positional `params` Hash with - # explicit keyword arguments cannot be called as `send_request(method, { ... })` - the trailing Hash would be - # auto-promoted to keyword arguments. Stdio is single-threaded and blocks on `$stdin.gets`, so nested-request - # cancellation has very limited value here regardless; servers that need cancellation propagation for nested - # server-to-client requests should use `StreamableHTTPTransport`. - def send_request(method, params = nil) - # The modern lifecycle (SEP-2575) forbids server-initiated JSON-RPC requests; - # multi round-trip `input_required` results (SEP-2322) replace them. - if @session && @session.era == :modern - raise "Server-initiated requests are not available in the modern lifecycle (SEP-2575)." - end - - request_id = generate_request_id - request = { jsonrpc: "2.0", id: request_id, method: method } - request[:params] = params if params - - begin - send_response(request) - rescue => e - MCP.configuration.exception_reporter.call(e, { error: "Failed to send request" }) - raise - end - - while @open && (line = read_line($stdin)) - begin - parsed = JSON.parse(line.strip, symbolize_names: true) - rescue JSON::ParserError => e - MCP.configuration.exception_reporter.call(e, { error: "Failed to parse response" }) - raise - end - - if parsed[:id] == request_id && !parsed.key?(:method) - if parsed[:error] - raise StandardError, "Client returned an error for #{method} request (code: #{parsed[:error][:code]}): #{parsed[:error][:message]}" - end - - return parsed[:result] - else - response = @session ? dispatch_with_era(parsed) : @server.handle(parsed) - send_response(response) if response - end - end - - raise "Transport closed while waiting for response to #{method} request." - end - - private - - # Reads one newline-delimited frame, bounded by `@max_line_bytes`. Returns - # the line (including its trailing newline) or `nil` at EOF. Raises when the - # limit is reached before a newline arrives, which signals a peer streaming - # an unbounded frame. A short final frame without a trailing newline (EOF) is - # still returned, since its length stays under the limit. - def read_line(io) - line = io.gets("\n", @max_line_bytes) - if line && !line.end_with?("\n") && line.bytesize >= @max_line_bytes - raise RequestHandlerError.new( - "stdio frame exceeds #{@max_line_bytes} bytes without a newline", - nil, - error_type: :internal_error, - ) - end - - line - end - - # Parses a frame once so era classification can inspect its method and `_meta`. - # Returns `nil` for frames that are not JSON objects; those fall back to - # `ServerSession#handle_json` so protocol-level error responses stay identical. - def parse_line(line) - parsed = JSON.parse(line, symbolize_names: true) - parsed.is_a?(Hash) ? parsed : nil - rescue JSON::ParserError - nil - end - - # Serves one frame under the dual-era model (SEP-2575): the first era-distinctive message to succeed locks - # the connection era. A successful `initialize` locks `:legacy` inside `Server#init`; a successful `server/discover` - # or a successful request carrying the full modern `_meta` triple locks `:modern`. Era-violating frames - # (an `initialize` after a modern lock, a modern envelope after a legacy lock, or a missing envelope after a modern lock) - # are rejected in-band by `Server#lift_request_envelope`. - def dispatch_with_era(parsed) - response = @session.handle(parsed) - lock_modern_era_on_success(parsed, response) - response - end - - def lock_modern_era_on_success(parsed, response) - return if @session.era - return if !response.is_a?(Hash) || response.key?(:error) - return if parsed[:method] != Methods::SERVER_DISCOVER && !RequestEnvelope.modern?(parsed[:params]) - - @session.lock_era!(:modern) - end end end end diff --git a/lib/mcp/server/transports/streamable_http_transport.rb b/lib/mcp/server/transports/streamable_http_transport.rb index b406d6d..350af7c 100644 --- a/lib/mcp/server/transports/streamable_http_transport.rb +++ b/lib/mcp/server/transports/streamable_http_transport.rb @@ -1,321 +1,26 @@ # frozen_string_literal: true -require "json" -require_relative "../../result_type" require_relative "../../transport" - -# This file is autoloaded only when `StreamableHTTPTransport` is referenced, -# so the `rack` dependency does not affect `StdioTransport` users. -begin - require "rack" -rescue LoadError - raise LoadError, "The 'rack' gem is required to use the StreamableHTTPTransport. " \ - "Add it to your Gemfile: gem 'rack'" -end +require "json" +require "securerandom" module MCP class Server module Transports class StreamableHTTPTransport < Transport - class InvalidJsonError < StandardError; end - - # `x-accel-buffering: no` tells reverse proxies (nginx and friends) not to buffer the response, - # which the spec asks of every SSE stream: a buffering proxy holds events back instead of - # delivering them as they are written, and on a long-lived `subscriptions/listen` stream that - # also swallows the keepalive frames a dropped peer would otherwise be detected by. - # The TypeScript and Python SDKs send it on their SSE responses for the same reason. - SSE_HEADERS = { - "content-type" => "text/event-stream", - "cache-control" => "no-cache", - "connection" => "keep-alive", - "x-accel-buffering" => "no", - }.freeze - - # Secure defaults for stateful mode. Without a finite idle timeout, sessions live until an explicit client DELETE, - # so an unauthenticated `initialize` flood retains unbounded `ServerSession` objects until memory is exhausted. - # These defaults expire idle sessions and cap the concurrent count, like the C# SDK (the only reference SDK that - # hardens this by default, with a 2h idle timeout and a 10k idle-session count). One difference: at the cap this transport - # rejects a new `initialize` with 503 (after reclaiming any already-expired slots), whereas the C# SDK evicts - # the oldest idle session. Rejecting keeps established sessions stable and avoids evicting a legitimate idle session on - # an attacker's behalf, at the cost of refusing new sessions while genuinely full. Pass `session_idle_timeout: nil` to - # opt out of expiry and `max_sessions: nil` to opt out of the cap. - DEFAULT_SESSION_IDLE_TIMEOUT = 1800 - DEFAULT_MAX_SESSIONS = 10_000 - - # Cap on concurrent `subscriptions/listen` streams (SEP-2575). Each stream holds an open SSE connection - # for its lifetime, so without a bound an unauthenticated client can retain unbounded connections, - # like the session-flood case `DEFAULT_MAX_SESSIONS` guards. A listen request past the cap is rejected with HTTP 503; - # pass `max_listen_subscriptions: nil` to opt out. - DEFAULT_MAX_LISTEN_SUBSCRIPTIONS = 1_000 - - # Distinguishes "argument omitted, apply the secure default" from an explicit `nil` (opt out of expiry). - UNSET_IDLE_TIMEOUT = Object.new.freeze - private_constant :UNSET_IDLE_TIMEOUT - - # Default deadline in seconds for a server-to-client request (sampling, elicitation, `roots/list`, `ping`). - # The spec asks implementations to bound every sent request so a peer that never answers cannot exhaust - # the sender's resources; without one, a client that opens a session and simply never replies parks - # a worker thread for good. - # - # Ten minutes matches the TypeScript SDK, which raises its uniform 60-second request default to 600 seconds - # for the legs of its legacy `input_required` shim because they are "human-paced, so the 60s protocol default - # is wrong". Every request this transport can send is that kind of leg: someone answering an elicitation - # prompt, or the client's own model producing a sample. (The Python SDK leaves the deadline unset and bounds - # nothing by default.) Deployments that want a tighter bound pass a smaller value here; a single handler - # that legitimately waits longer passes `timeout:`. - # - # https://modelcontextprotocol.io/specification/2025-11-25/basic/lifecycle#timeouts - DEFAULT_SERVER_TO_CLIENT_REQUEST_TIMEOUT = 600 - - # Default upper bound on the JSON-RPC request body. `handle_post` reads the whole - # body into memory and parses it, so without a cap a single unauthenticated POST - # can allocate gigabytes and OOM the worker. 4 MiB comfortably - # fits a typical JSON-RPC request (a 4 MiB JSON string decodes to ~3 MiB of base64 - # payload); raise `max_request_bytes:` for unusually large payloads. Matches the - # TypeScript SDK's 4 MB default. - DEFAULT_MAX_REQUEST_BYTES = 4 * 1024 * 1024 - - # Conservative bound on JSON nesting depth, so a deeply nested body cannot exhaust - # the stack or amplify parse cost (complements the byte cap). - MAX_JSON_NESTING = 64 - - # Cap on the notifications buffered for one modern request (SEP-2575). The sink holds them - # in memory until the handler returns, so a handler that emits notifications in proportion to - # client-supplied input would otherwise let one request grow memory without bound. - # Notifications past the cap are not delivered and the notify helpers report `false`, - # the same non-delivery degradation they have on every other undeliverable path. - MAX_MODERN_REQUEST_NOTIFICATIONS = 1_000 - - # Interval in seconds between SSE keepalive comment frames on a `subscriptions/listen` stream. - # Without them a silently dropped connection holds its slot until the next fan-out write fails, - # so on a quiet server a dead peer would occupy a `max_listen_subscriptions` slot indefinitely. - # The periodic write detects the dead peer and frees the slot. Matches the TypeScript SDK's - # 15-second default; pass `listen_keepalive_interval: nil` when an upstream proxy pings the stream. - DEFAULT_LISTEN_KEEPALIVE_INTERVAL = 15 - - # Creates a Streamable HTTP transport that can be mounted as a Rack app. - # - # @param server [MCP::Server] the server whose requests this transport dispatches. - # @param stateless [Boolean] when `true`, no session is issued and each POST is self-contained. - # @param enable_json_response [Boolean] when `true`, a request is answered with a single JSON - # object instead of an SSE stream. - # @param session_idle_timeout [Numeric, nil] seconds before an idle session is reaped; defaults - # to `DEFAULT_SESSION_IDLE_TIMEOUT` (1800) in stateful mode, and an explicit `nil` disables - # expiry. Not supported in stateless mode. - # @param max_sessions [Integer, nil] cap on the concurrent session count in stateful mode; a new - # `initialize` past the cap is rejected with HTTP 503, and `nil` disables the cap. - # @param allowed_origins [Array, nil] extra `Origin` values accepted in addition to - # same-origin requests, for DNS rebinding protection. - # @param allowed_hosts [Array, nil] extra `Host` values accepted beyond the loopback - # defaults (`127.0.0.1`, `::1`, `localhost`); each entry matches a bare host name (any port) - # or a full `host:port`. - # @param dns_rebinding_protection [Boolean] when `true` (default), validates the `Host` and - # `Origin` headers to prevent DNS rebinding; pass `false` when an upstream proxy already - # validates them. - # @param session_request_validator [#call, nil] An optional - # `->(request, session_id) { true | false }` invoked on every non-`initialize` POST, GET, and DELETE - # against an existing session (regular requests, notifications, and client responses alike). - # Returning a falsy value rejects the request with HTTP 403. The SDK issues a random `SecureRandom.uuid` - # session ID and otherwise only checks existence/idle-timeout, so binding a session to a user is - # the deploying application's responsibility (the transport never receives the authenticated identity - # on its own); this is the seam to enforce ownership and mitigate session poisoning. Without a validator, - # ownership is not enforced. - # @param max_request_bytes [Integer] upper bound in bytes on a POST request body; larger - # requests are rejected with HTTP 413. Defaults to 4 MiB. - # @param max_listen_subscriptions [Integer, nil] cap on concurrent `subscriptions/listen` - # streams; a listen request past the cap is rejected with HTTP 503, and `nil` disables - # the cap. - # @param listen_keepalive_interval [Numeric, nil] seconds between SSE keepalive comment frames - # on a `subscriptions/listen` stream; the periodic write frees the stream's slot when the peer - # has gone away. Defaults to `DEFAULT_LISTEN_KEEPALIVE_INTERVAL` (15); pass `nil` to disable - # when an upstream proxy already keeps the stream alive. - # @param serve_subscriptions_listen [Boolean] whether `subscriptions/listen` opens a stream. - # A host that buffers responses and cannot serve an open SSE stream (e.g. the Rails controller pattern, - # which builds a fresh transport per request and renders the body) passes `false`: - # the method then answers 404 with JSON-RPC `-32601` like any unimplemented method, - # and `Server#discover` stops advertising the `listChanged`/`subscribe` capability flags, - # keeping the advertisement and the actual behavior in agreement. Defaults to `true`. - # @param server_to_client_request_timeout [Numeric] seconds a server-to-client request waits for its - # response before the transport stops waiting and raises `MCP::Server::RequestTimeoutError`. - # Defaults to `DEFAULT_SERVER_TO_CLIENT_REQUEST_TIMEOUT` (600); individual calls override it with `timeout:`. - def initialize( - server, - stateless: false, - enable_json_response: false, - session_idle_timeout: UNSET_IDLE_TIMEOUT, - max_sessions: DEFAULT_MAX_SESSIONS, - allowed_origins: nil, - allowed_hosts: nil, - dns_rebinding_protection: true, - session_request_validator: nil, - max_request_bytes: DEFAULT_MAX_REQUEST_BYTES, - max_listen_subscriptions: DEFAULT_MAX_LISTEN_SUBSCRIPTIONS, - listen_keepalive_interval: DEFAULT_LISTEN_KEEPALIVE_INTERVAL, - serve_subscriptions_listen: true, - server_to_client_request_timeout: DEFAULT_SERVER_TO_CLIENT_REQUEST_TIMEOUT - ) + def initialize(server, stateless: false) super(server) - # Maps `session_id` to `{ get_sse_stream: stream_object, server_session: ServerSession, last_active_at: float_from_monotonic_clock, origin: origin_header }`. + # { session_id => { stream: stream_object } @sessions = {} @mutex = Mutex.new @stateless = stateless - @enable_json_response = enable_json_response - @session_request_validator = session_request_validator - @dns_rebinding_protection = dns_rebinding_protection - - # Host names are case-insensitive, so the allow lists are compared down-cased. - @allowed_hosts = (DEFAULT_LOOPBACK_HOSTS + Array(allowed_hosts)).map(&:downcase).freeze - @allowed_origins = Array(allowed_origins).map(&:downcase).freeze - @pending_responses = {} - - # Maps a `subscriptions/listen` request id to - # `{ stream: stream_object, filter: honored_subscription_filter, active: boolean, write_mutex: Mutex }` (SEP-2575). - # In-process only; a multi-worker deployment needs an external event bus to fan notifications out across processes, - # which is a follow-up. - @listen_subscriptions = {} - - # Maps a modern request's ephemeral session id to the Array collecting the notifications its handler emits; - # `handle_modern` registers the sink and flushes it as SSE frames ahead of the final response (SEP-2575). - @modern_request_sinks = {} - - # Resolve the idle timeout: an explicit value (including `nil` to opt out) wins; otherwise apply the secure default, - # which does not apply to stateless mode since it retains no sessions. - @session_idle_timeout = if session_idle_timeout.equal?(UNSET_IDLE_TIMEOUT) - stateless ? nil : DEFAULT_SESSION_IDLE_TIMEOUT - else - session_idle_timeout - end - - if @session_idle_timeout - if @stateless - raise ArgumentError, "session_idle_timeout is not supported in stateless mode." - elsif @session_idle_timeout <= 0 - raise ArgumentError, "session_idle_timeout must be a positive number." - end - end - - unless max_sessions.nil? || (max_sessions.is_a?(Integer) && max_sessions > 0) - raise ArgumentError, "max_sessions must be a positive Integer or nil" - end - - # The cap guards the stateful session store; stateless mode keeps none. - @max_sessions = stateless ? nil : max_sessions - - unless max_request_bytes.is_a?(Integer) && max_request_bytes > 0 - raise ArgumentError, "max_request_bytes must be a positive Integer" - end - - @max_request_bytes = max_request_bytes - - if !max_listen_subscriptions.nil? && !(max_listen_subscriptions.is_a?(Integer) && max_listen_subscriptions > 0) - raise ArgumentError, "max_listen_subscriptions must be a positive Integer or nil" - end - - @max_listen_subscriptions = max_listen_subscriptions - - if !listen_keepalive_interval.nil? && !(listen_keepalive_interval.is_a?(Numeric) && listen_keepalive_interval > 0) - raise ArgumentError, "listen_keepalive_interval must be a positive number or nil" - end - - @listen_keepalive_interval = listen_keepalive_interval - @serve_subscriptions_listen = serve_subscriptions_listen - - unless server_to_client_request_timeout.is_a?(Numeric) && server_to_client_request_timeout.positive? - raise ArgumentError, "server_to_client_request_timeout must be a positive number" - end - - @server_to_client_request_timeout = server_to_client_request_timeout - - start_reaper_thread if @session_idle_timeout end - REQUIRED_POST_ACCEPT_TYPES_SSE = ["application/json", "text/event-stream"].freeze - REQUIRED_POST_ACCEPT_TYPES_JSON = ["application/json"].freeze + REQUIRED_POST_ACCEPT_TYPES = ["application/json", "text/event-stream"].freeze REQUIRED_GET_ACCEPT_TYPES = ["text/event-stream"].freeze - STREAM_WRITE_ERRORS = [IOError, Errno::EPIPE, Errno::ECONNRESET].freeze - SESSION_REAP_INTERVAL = 60 - - # Loopback hosts always accepted by DNS rebinding protection. A locally bound MCP server (the canonical pattern) is - # protected out of the box; non-loopback deployments widen the list via `allowed_hosts:`. - DEFAULT_LOOPBACK_HOSTS = ["127.0.0.1", "::1", "localhost"].freeze - - # JSON-RPC methods whose target name is mirrored into the `Mcp-Name` header (SEP-2575). - NAME_BEARING_METHODS = [Methods::TOOLS_CALL, Methods::RESOURCES_READ, Methods::PROMPTS_GET].freeze - - # Maps broadcast notification methods to the `SubscriptionFilter` field that opts in to them on - # a `subscriptions/listen` stream (SEP-2575). `notifications/resources/updated` is matched by URI - # against `resourceSubscriptions` instead. - LISTEN_FILTER_FIELDS = { - Methods::NOTIFICATIONS_TOOLS_LIST_CHANGED => :toolsListChanged, - Methods::NOTIFICATIONS_PROMPTS_LIST_CHANGED => :promptsListChanged, - Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED => :resourcesListChanged, - }.freeze - - # JSON-RPC error codes that surface as HTTP 400 on the modern path. `-32601` maps to 404 - # (disambiguating an unknown method from a legacy HTTP+SSE 404) and everything else, including internal errors, - # stays 200, matching the Python SDK's status ladder. - MODERN_BAD_REQUEST_CODES = [ - ErrorCodes::HEADER_MISMATCH, - ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY, - ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, - JsonRpcHandler::ErrorCode::PARSE_ERROR, - JsonRpcHandler::ErrorCode::INVALID_REQUEST, - JsonRpcHandler::ErrorCode::INVALID_PARAMS, - ].freeze - - # Rack app interface. This transport can be mounted as a Rack app. - def call(env) - handle_request(Rack::Request.new(env)) - end - - # Whether this transport serves the `subscriptions/listen` notification stream (SEP-2575). - # Gates both the route (a refusing transport answers the method as unimplemented) and - # the `listChanged`/`subscribe` capability flags `Server#discover` advertises, - # so the two always agree. Set via the `serve_subscriptions_listen:` constructor keyword. - def serves_subscriptions_listen? - @serve_subscriptions_listen - end def handle_request(request) - rebinding_error = validate_dns_rebinding(request) - return rebinding_error if rebinding_error - - # Header-primary era routing (SEP-2575). An `MCP-Protocol-Version` header naming a version outside - # every supported list routes to the sessionless modern path, so an unknown future version receives - # the spec-mandated `-32022` with the supported list instead of the legacy path's generic invalid-request error. - # Requests without the header, or with a stable-only version, take the existing paths untouched. - # An empty header value is malformed rather than a version claim, so it stays on the legacy path - # and fails legacy header validation as before. - # - # A modern header value (2026-07-28) alone cannot decide the era: sessionless modern traffic carries it, - # and requests of an established legacy session may stamp it as well (the handshake itself never negotiates it): - # an `Mcp-Session-Id` binds the request to an established legacy session (POST requests, the GET SSE stream, - # and DELETE termination keep working), and a session-less POST whose body is `initialize` is - # the legacy-distinctive handshake. Everything else under a dual-era header is sessionless modern traffic - # (`server/discover`, envelope-carrying requests, and envelope-missing requests that get the modern path's error shape). - header_version = request.env["HTTP_MCP_PROTOCOL_VERSION"] - if header_version && !header_version.empty? && !stable_only_version?(header_version) - unless MCP::Configuration.modern_protocol_version?(header_version) - return handle_modern(request, header_version) - end - - if extract_session_id(request).nil? - return handle_modern(request, header_version) unless request.env["REQUEST_METHOD"] == "POST" - - # The body is readable only once (Rack 3 inputs need not be rewindable), so the era sniff reads it here, - # bounded, and hands the string to whichever path serves the request. - body_string = read_bounded_body(request) - return payload_too_large_response if body_string.nil? - - unless legacy_handshake_body?(body_string) - return handle_modern(request, header_version, body_string: body_string) - end - - return handle_post(request, body_string: body_string) - end - end - case request.env["REQUEST_METHOD"] when "POST" handle_post(request) @@ -329,27 +34,14 @@ module MCP end def close - @reaper_thread&.kill - @reaper_thread = nil - - teardown_listen_subscriptions - - removed_sessions = @mutex.synchronize do - @sessions.each_key.filter_map { |session_id| cleanup_session_unsafe(session_id) } - end - - removed_sessions.each do |session| - close_stream_safely(session[:get_sse_stream]) - close_post_request_streams(session) + @mutex.synchronize do + @sessions.each_key { |session_id| cleanup_session_unsafe(session_id) } end end - def send_notification(method, params = nil, session_id: nil, related_request_id: nil) - # `subscriptions/listen` streams (SEP-2575) receive matching change notifications regardless of the delivery below: - # a resource updated by one session's tool call changed globally, so modern subscribers hear about it too. - # Runs before the per-request sink and the stateless guard because the listen registry does not depend on sessions, - # and a sink capturing the notification for its own response stream must not hide it from other subscriptions. - deliver_to_listen_subscriptions(method, params) + def send_notification(method, params = nil, session_id: nil) + # Stateless mode doesn't support notifications + raise "Stateless mode does not support notifications" if @stateless notification = { jsonrpc: "2.0", @@ -357,934 +49,84 @@ module MCP } notification[:params] = params if params - # A modern request's notifications ride its own response stream (SEP-2575): `handle_modern` registers - # a per-request sink for its ephemeral session and flushes it as SSE frames ahead of the final response. - # Checked before the stateless guard, since modern requests are served in stateless deployments too. - # The sink is bounded; past `MAX_MODERN_REQUEST_NOTIFICATIONS` the notification is dropped as - # non-delivery (`false`), never handed to the legacy paths below. - sink = @mutex.synchronize { session_id && @modern_request_sinks[session_id] } - if sink - return false if sink.size >= MAX_MODERN_REQUEST_NOTIFICATIONS + @mutex.synchronize do + if session_id + # Send to specific session + session = @sessions[session_id] + return false unless session && session[:stream] - sink << notification - return true - end + begin + send_to_stream(session[:stream], notification) + true + rescue IOError, Errno::EPIPE => e + MCP.configuration.exception_reporter.call( + e, + { session_id: session_id, error: "Failed to send notification" }, + ) + cleanup_session_unsafe(session_id) + false + end + else + # Broadcast to all connected SSE sessions + sent_count = 0 + failed_sessions = [] - # Stateless mode has no streams to deliver notifications on. Report non-delivery instead of raising - # so the ephemeral per-request session's notify_* helpers (e.g. progress or log notifications from - # a tool handler) degrade gracefully rather than spamming the exception reporter on every call. - return false if @stateless + @sessions.each do |sid, session| + next unless session[:stream] - if session_id - deliver_targeted_notification(notification, session_id, related_request_id) - else - deliver_broadcast_notification(notification) - end - end - - def deliver_targeted_notification(notification, session_id, related_request_id) - # JSON response mode returns a single JSON object as the POST response, - # so request-scoped notifications (e.g. progress, log) cannot be delivered - # alongside it. Session-scoped standalone notifications - # (e.g. `resources/updated`, `elicitation/complete`) still flow via GET SSE. - return false if @enable_json_response && related_request_id - - streams_to_close = [] - - # Resolve the target stream under the lock, then write outside it: a stalled SSE reader - # must not block every other session that needs `@mutex`. - stream = @mutex.synchronize do - next unless (session = @sessions[session_id]) - - if session_expired?(session) - cleanup_and_collect_stream(session_id, streams_to_close) - next - end - - active_stream(session, related_request_id: related_request_id) - end - - close_streams(streams_to_close) - return false unless stream - - write_notification(stream, notification, session_id, related_request_id) - end - - def deliver_broadcast_notification(notification) - streams_to_close = [] - - # Snapshot the connected streams under the lock, then write to each outside it. - targets = @mutex.synchronize do - expired_session_ids = [] - - collected = @sessions.filter_map do |session_id, session| - next unless (stream = session[:get_sse_stream]) - - if session_expired?(session) - expired_session_ids << session_id - next + begin + send_to_stream(session[:stream], notification) + sent_count += 1 + rescue IOError, Errno::EPIPE => e + MCP.configuration.exception_reporter.call( + e, + { session_id: sid, error: "Failed to send notification" }, + ) + failed_sessions << sid + end end - [session_id, stream] - end + # Clean up failed sessions + failed_sessions.each { |sid| cleanup_session_unsafe(sid) } - expired_session_ids.each do |session_id| - cleanup_and_collect_stream(session_id, streams_to_close) - end - - collected - end - - close_streams(streams_to_close) - - targets.count do |session_id, stream| - write_notification(stream, notification, session_id, nil) - end - end - - # Writes a notification to an SSE stream without holding `@mutex`. On a write error, - # drops the broken stream and returns false; on success returns true. - def write_notification(stream, notification, session_id, related_request_id) - send_to_stream(stream, notification) - true - rescue *STREAM_WRITE_ERRORS => e - MCP.configuration.exception_reporter.call(e, { session_id: session_id, error: "Failed to send notification" }) - drop_broken_stream(session_id, stream, related_request_id) - false - end - - # Removes a stream that failed to accept a write. A request-scoped stream is dropped on its own; - # a session-scoped (GET SSE) failure tears down the whole session. The `@sessions` mutation runs - # under `@mutex`, and the affected streams are closed outside it. - def drop_broken_stream(session_id, stream, related_request_id) - streams_to_close = [] - - @mutex.synchronize do - session = @sessions[session_id] - if related_request_id - # Unregister only our own stream: removing on the id alone would drop whichever stream currently holds it, - # which is not necessarily the one that failed. The failed stream is closed either way, and a request-scoped - # failure never reaches the session teardown below. - registered = session&.dig(:post_request_streams, related_request_id) - session[:post_request_streams].delete(related_request_id) if registered.equal?(stream) - - streams_to_close << stream - else - cleanup_and_collect_stream(session_id, streams_to_close) - end - end - - close_streams(streams_to_close) - end - - def close_streams(streams) - streams.each do |stream| - close_stream_safely(stream) - end - end - - # Sends a server-to-client JSON-RPC request (e.g., `sampling/createMessage`) and blocks until - # the client responds. - # - # Uses a `PendingResponse` for cross-thread synchronization: this method registers one, - # sends the request via SSE stream, then waits on it. When the client POSTs a response, - # `handle_response` matches it by `request_id` and resolves the pending response, - # unblocking this thread. A cancellation and session teardown resolve it the same way. - # - # The wait is bounded by `timeout` (defaulting to the transport's `server_to_client_request_timeout`), - # so a client that never answers cannot park the calling thread for good. On expiry the peer is - # sent `notifications/cancelled` and `MCP::Server::RequestTimeoutError` is raised. - def send_request(method, params = nil, session_id: nil, related_request_id: nil, parent_cancellation: nil, server_session: nil, timeout: nil) - # The modern lifecycle (SEP-2575) forbids server-initiated JSON-RPC requests; - # multi round-trip `input_required` results (SEP-2322) replace them. A modern session has never reached - # the rest of this method anyway, since `handle_modern` mints its session without registering it in `@sessions`, - # but that is incidental: without the rule stated here a modern handler that reaches for elicitation - # or sampling is told "Session not found: ", which points at everything except the actual reason. - # `StdioTransport#send_request` refuses the same way. - if server_session&.era == :modern - raise "Server-initiated requests are not available in the modern lifecycle (SEP-2575)." - end - - if @stateless - raise "Stateless mode does not support server-to-client requests." - end - - if @enable_json_response - raise "JSON response mode does not support server-to-client requests." - end - - unless session_id - raise "session_id is required for server-to-client requests." - end - - request_id = generate_request_id - pending_response = PendingResponse.new - wait_timeout = timeout || @server_to_client_request_timeout - cancel_hook = nil - - request = { jsonrpc: "2.0", id: request_id, method: method } - request[:params] = params if params - - # Register the pending response and resolve the stream under the lock, but perform - # the write outside it so a stalled reader cannot block every other session on `@mutex`. - stream = @mutex.synchronize do - unless (session = @sessions[session_id]) - raise "Session not found: #{session_id}." - end - - @pending_responses[request_id] = { queue: pending_response, session_id: session_id } - - active_stream(session, related_request_id: related_request_id) - end - - sent = false - if stream - begin - send_to_stream(stream, request) - sent = true - rescue *STREAM_WRITE_ERRORS - drop_broken_stream(session_id, stream, related_request_id) - end - end - - # TODO: Replace with event store + replay when resumability is implemented. - # Resumability is a separate MCP specification feature (SSE event IDs, Last-Event-ID replay, - # event store management) independent of sampling. - # See: https://modelcontextprotocol.io/specification/latest/basic/transports#resumability-and-redelivery - # - # The TypeScript and Python SDKs buffer messages and replay on reconnect. - # Until then, raise to prevent queue.pop from blocking indefinitely. - unless sent - raise "No active stream for #{method} request." - end - - if parent_cancellation && server_session - cancel_hook = parent_cancellation.on_cancel do |reason| - server_session.send_peer_cancellation( - nested_request_id: request_id, - related_request_id: related_request_id, - reason: reason, - ) - end - end - - response = pending_response.pop(timeout: wait_timeout) do - # Expiry cancels as well as stops waiting, so a client that answers late does not act on - # a request the server has abandoned. Only connections speaking 2025-11-25 or earlier get here: - # the modern lifecycle forbids server-to-client requests outright, and its sessionless requests - # never register the session this method looks up. Those revisions ask the sender to "issue - # a cancellation notification for that request and stop waiting", letting either side send one. - # (The 2026-07-28 rule reserving `notifications/cancelled` for `subscriptions/listen` teardown - # governs the era that has no such requests to cancel.) Both reference SDKs send this same - # courtesy cancel on timeout. - server_session&.send_peer_cancellation( - nested_request_id: request_id, - related_request_id: related_request_id, - reason: "Timed out after #{wait_timeout} seconds", - ) - - raise RequestTimeoutError.new( - "#{method} request timed out after #{wait_timeout} seconds", - request_id: request_id, - timeout: wait_timeout, - ) - end - - if response.is_a?(Hash) && response.key?(:error) - raise StandardError, "Client returned an error for #{method} request (code: #{response[:error][:code]}): #{response[:error][:message]}" - end - - if response == :session_closed - raise "SSE session closed while waiting for #{method} response." - end - - if response == :cancelled - reason = @mutex.synchronize { @pending_responses.dig(request_id, :cancel_reason) } - raise MCP::CancelledError.new( - "#{method} request was cancelled", - request_id: request_id, - reason: reason, - ) - end - - response - ensure - parent_cancellation.off_cancel(cancel_hook) if cancel_hook - if request_id - @mutex.synchronize do - @pending_responses.delete(request_id) - end - end - end - - # Unblocks a `send_request` awaiting a response when the peer is being cancelled. - # The waiting thread will see `:cancelled` on its queue and raise `MCP::CancelledError`. - # - # Race note: this is first-writer-wins on the pending-response queue. If a real response - # has already been pushed (client responded before the cancel hook fired), that response - # wins and `:cancelled` is enqueued behind it but never read - `send_request` returns - # the real response and deletes the pending entry in its `ensure` block. Conversely, - # if `:cancelled` arrives first, any later client response is silently dropped in `handle_response` - # because the pending entry has been removed. - def cancel_pending_request(request_id, reason: nil) - @mutex.synchronize do - if (pending = @pending_responses[request_id]) - pending[:cancel_reason] = reason - pending[:queue].push(:cancelled) + sent_count end end end private - def start_reaper_thread - @reaper_thread = Thread.new do - loop do - sleep(SESSION_REAP_INTERVAL) - reap_expired_sessions - rescue StandardError => e - MCP.configuration.exception_reporter.call(e, error: "Session reaper error") - end - end - end - - def reap_expired_sessions - return unless @session_idle_timeout - - removed_sessions = @mutex.synchronize do - @sessions.each_key.filter_map do |session_id| - next unless session_expired?(@sessions[session_id]) - - cleanup_session_unsafe(session_id) - end - end - - removed_sessions.each do |session| - close_stream_safely(session[:get_sse_stream]) - close_post_request_streams(session) - end - end - def send_to_stream(stream, data) message = data.is_a?(String) ? data : data.to_json stream.write("data: #{message}\n\n") - stream.flush + stream.flush if stream.respond_to?(:flush) end def send_ping_to_stream(stream) stream.write(": ping #{Time.now.iso8601}\n\n") - stream.flush + stream.flush if stream.respond_to?(:flush) end - # Serves one request of the stateless modern lifecycle (MCP 2026-07-28, SEP-2575): - # a single POST/JSON exchange with no session. The modern path never consults - # `@stateless`, `@sessions`, or `@enable_json_response`, and never issues or accepts - # an `Mcp-Session-Id`. GET (the legacy listening stream, replaced by `subscriptions/listen`) - # and DELETE (session termination) have no modern meaning. - def handle_modern(request, header_version, body_string: nil) - return method_not_allowed_response unless request.env["REQUEST_METHOD"] == "POST" - - accept_error = validate_accept_header(request, REQUIRED_POST_ACCEPT_TYPES_SSE) + def handle_post(request) + accept_error = validate_accept_header(request, REQUIRED_POST_ACCEPT_TYPES) return accept_error if accept_error - content_type_error = validate_content_type(request) - return content_type_error if content_type_error - - if body_string.nil? - body_string = read_bounded_body(request) - return payload_too_large_response if body_string.nil? - end - - begin - body = parse_request_body(body_string) - rescue InvalidJsonError - return invalid_json_response - end - - unless body.is_a?(Hash) - return invalid_request_response("Invalid Request: JSON-RPC body must be a single request object") - end - - # The version check precedes everything else that depends on request content, - # so a client probing with an unknown future version always receives the `-32022` signal - # (with the supported list to select from) rather than an incidental error. - unless MCP::Configuration.modern_protocol_version?(header_version) - return json_rpc_error_response( - status: 400, - code: ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, - message: "Unsupported protocol version", - data: { - supported: MCP::Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, - requested: header_version, - }, - id: body[:id], - ) - end - - if extract_session_id(request) - return json_rpc_error_response( - status: 400, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Bad Request: Mcp-Session-Id is not accepted in the modern lifecycle", - id: body[:id], - ) - end - - mismatch_error = validate_modern_headers(request, body, header_version) - return mismatch_error if mismatch_error - - # `subscriptions/listen` is a long-lived notification stream served at the transport layer; - # it never dispatches through `Server#handle`. A transport constructed with - # `serve_subscriptions_listen: false` skips the interception, so the method falls through - # to the dispatcher as unimplemented (404 with `-32601`) - the refusal a host that cannot - # serve an open SSE stream needs, instead of a `Proc` body it can never call. - if body[:method] == Methods::SUBSCRIPTIONS_LISTEN && serves_subscriptions_listen? - return handle_subscriptions_listen(body) - end - - session = modern_session - notifications = @mutex.synchronize { @modern_request_sinks[session.session_id] = [] } - begin - response = @server.handle(body, session: session) - ensure - @mutex.synchronize { @modern_request_sinks.delete(session.session_id) } - end - - # `nil` covers notifications and cancellation-suppressed responses; ack with 202 like the legacy notification path. - return handle_accepted if response.nil? - - # Notifications a handler emitted during the request ride the request's own response stream as SSE frames ahead of - # the final response (SEP-2575); a request that emitted none keeps the single JSON exchange and its HTTP status ladder. - # Delivery is buffered: frames flush after the handler returns, preserving order but not real-time interleaving - # (the TypeScript and Python SDKs stream live), and the sink grows with the handler's notification count. - # Live streaming can follow without changing the wire shape. - if notifications.empty? - [modern_http_status(response), { "content-type" => "application/json" }, [response.to_json]] - else - frames = notifications + [response] - sse_body = frames.map { |frame| "event: message\ndata: #{frame.to_json}\n\n" }.join - [200, SSE_HEADERS.dup, [sse_body]] - end - rescue StandardError => e - MCP.configuration.exception_reporter.call(e, { request: body_string }) - json_rpc_error_response( - status: 500, - code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - message: "Internal server error", - ) - end - - # Enforces the SEP-2575 header/body match rules (`-32020`, HTTP 400): the `MCP-Protocol-Version` header - # MUST match the `_meta`-carried version, and the `Mcp-Method` / `Mcp-Name` mirror headers MUST match - # the body when sent. Absent mirror headers are tolerated for interoperability while other SDK serving stacks - # converge on enforcement. - def validate_modern_headers(request, body, header_version) - params = body[:params] - meta_version = params.is_a?(Hash) ? params.dig(:_meta, :"io.modelcontextprotocol/protocolVersion") : nil - if meta_version && meta_version != header_version - return header_mismatch_response( - "MCP-Protocol-Version header value '#{header_version}' does not match body value '#{meta_version}'", - body[:id], - ) - end - - # `Mcp-Method` is required on every modern POST and `Mcp-Name` on the name-bearing methods: - # the spec lists a missing required standard header among the validation failures that MUST be rejected, - # and the TypeScript SDK enforces presence the same way. Absence cannot be treated as "nothing to compare": - # the headers exist so intermediaries can route without parsing bodies, and a client that omits them - # defeats that contract silently. - method_header = request.env["HTTP_MCP_METHOD"] - if method_header.to_s.empty? - return header_mismatch_response( - "Mcp-Method header is required on the modern path", - body[:id], - ) - end - if method_header != body[:method] - return header_mismatch_response( - "Mcp-Method header value '#{method_header}' does not match body value '#{body[:method]}'", - body[:id], - ) - end - - if NAME_BEARING_METHODS.include?(body[:method]) - body_name = params.is_a?(Hash) ? params[:name] || params[:uri] : nil - name_header = request.env["HTTP_MCP_NAME"] - if body_name - if name_header.to_s.empty? - return header_mismatch_response( - "Mcp-Name header is required for `#{body[:method]}`", - body[:id], - ) - end - - decoded_name = decode_header_value(name_header) - if decoded_name != body_name - return header_mismatch_response( - "Mcp-Name header value '#{decoded_name}' does not match body value '#{body_name}'", - body[:id], - ) - end - end - end - - nil - end - - # Serves `subscriptions/listen` (SEP-2575): opens a long-lived SSE stream whose first message is - # `notifications/subscriptions/acknowledged` with the subset of requested notification types - # the server agreed to honor. Notifications delivered on the stream carry `io.modelcontextprotocol/subscriptionId` - # (= the listen request id) in `_meta`. A graceful teardown (transport `close`) sends a `SubscriptionsListenResult` - # response; an abrupt disconnect sends nothing. A keepalive comment frame is written every - # `listen_keepalive_interval` seconds so a dropped connection frees its slot. - def handle_subscriptions_listen(body) - request_id = body[:id] - params = body[:params] - - # A listen frame without an id could never receive stream teardown correlation. - unless request_id - return invalid_request_response("Invalid Request: subscriptions/listen requires an id") - end - - begin - if RequestEnvelope.modern?(params) - RequestEnvelope.parse!(params, request: params) - else - return invalid_request_response("Invalid Request: modern requests require the SEP-2575 `_meta` envelope") - end - rescue Server::RequestHandlerError => e - return json_rpc_error_response( - status: 400, - code: e.error_code || JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: e.message, - data: e.error_data, - id: request_id, - ) - end - - filter = params[:notifications] - unless filter.is_a?(Hash) - return json_rpc_error_response( - status: 400, - code: JsonRpcHandler::ErrorCode::INVALID_PARAMS, - message: "Invalid params: subscriptions/listen requires a `notifications` filter object", - id: request_id, - ) - end - - # Best-effort cap check before committing to the SSE response; the registration inside - # `listen_sse_body` re-checks atomically for the race between two concurrent listens - # crossing the cap together. - if listen_subscriptions_full? - return too_many_listen_subscriptions_response(request_id) - end - - [200, SSE_HEADERS.dup, listen_sse_body(request_id, honored_filter(filter))] - end - - def listen_subscriptions_full? - return false unless @max_listen_subscriptions - - @mutex.synchronize { @listen_subscriptions.size >= @max_listen_subscriptions } - end - - def too_many_listen_subscriptions_response(request_id) - json_rpc_error_response( - status: 503, - code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - message: "Service unavailable: maximum concurrent subscriptions/listen streams (#{@max_listen_subscriptions}) reached", - id: request_id, - ) - end - - # The Rack streaming body of a `subscriptions/listen` response. It responds to `call` - # and deliberately not to `each`, so Rack keeps classifying it as a streaming body; - # `first` exists only to turn the buffered-host mistake (e.g. `render(json: body.first)` - # in the Rails controller pattern) from a bare `NoMethodError` into guidance naming the fix. - class ListenStreamBody - def initialize(&block) - @block = block - end - - def call(stream) - @block.call(stream) - end - - def first - raise <<~MESSAGE - subscriptions/listen returned a streaming SSE body, which cannot be buffered into a JSON response. \ - A host that cannot hold an SSE response open should construct the transport with `serve_subscriptions_listen: false`, \ - so the method is answered as unimplemented instead. - See the Rails (controller) section at https://ruby.sdk.modelcontextprotocol.io/server/transports/ for the hosting patterns. - MESSAGE - end - end - private_constant :ListenStreamBody - - # The body registers the stream and returns, leaving the response open like - # the legacy GET stream (`create_sse_body`). - # - # Registration and activation are split on purpose: the entry is inserted inactive - # (reserving the id and the cap slot atomically), the acknowledgement is written outside the lock, - # and only then does the entry become eligible for delivery. A concurrent notification between - # the insert and the acknowledgement write skips the inactive entry, - # enforcing the SEP-2575 rule that no notification precedes the acknowledgement. - def listen_sse_body(request_id, honored) - ListenStreamBody.new do |stream| - rejected = false - @mutex.synchronize do - if @listen_subscriptions.key?(request_id) || - (@max_listen_subscriptions && @listen_subscriptions.size >= @max_listen_subscriptions) - rejected = true - else - @listen_subscriptions[request_id] = { stream: stream, filter: honored, active: false, write_mutex: Mutex.new } - end - end - - if rejected - close_stream_safely(stream) - else - acknowledgement = { - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_SUBSCRIPTIONS_ACKNOWLEDGED, - params: { - notifications: honored, - _meta: { RequestEnvelope::SUBSCRIPTION_ID_META_KEY.to_sym => request_id }, - }, - } - - begin - send_to_stream(stream, acknowledgement) - activate_listen_subscription(request_id) - start_listen_keepalive_thread(request_id) - rescue *STREAM_WRITE_ERRORS - remove_listen_subscription(request_id) - close_stream_safely(stream) - end - end - end - end - - # Marks a listen subscription eligible for delivery once its acknowledgement write has completed. - # The entry may already be gone when the transport closed concurrently. - def activate_listen_subscription(request_id) - @mutex.synchronize do - subscription = @listen_subscriptions[request_id] - subscription[:active] = true if subscription - end - end - - # Periodically writes an SSE keepalive comment frame to a listen stream so a silently dropped - # connection is detected and its slot freed, rather than held until the next fan-out write. - # Mirrors the legacy GET stream's `start_keepalive_thread`; a comment frame (not a data frame) - # cannot corrupt an interleaved notification's JSON. - def start_listen_keepalive_thread(request_id) - return unless @listen_keepalive_interval - - Thread.new do - while listen_subscription_active?(request_id) - sleep(@listen_keepalive_interval) - send_listen_keepalive_ping(request_id) - end - rescue *STREAM_WRITE_ERRORS - # The peer went away; the ensure frees the slot. A dropped listen stream is the normal - # way this loop ends, so it is not reported. - rescue StandardError => e - MCP.configuration.exception_reporter.call(e, { subscription_id: request_id }) - ensure - stream = @mutex.synchronize do - subscription = @listen_subscriptions.delete(request_id) - subscription && subscription[:stream] - end - close_stream_safely(stream) if stream - end - end - - def listen_subscription_active?(request_id) - @mutex.synchronize { @listen_subscriptions.key?(request_id) } - end - - # Resolves the stream under the lock, then writes outside it so a stalled reader cannot block - # every other subscription on `@mutex`. A write error propagates to end the keepalive loop. - def send_listen_keepalive_ping(request_id) - stream = @mutex.synchronize do - subscription = @listen_subscriptions[request_id] - subscription && subscription[:stream] - end - return unless stream - - send_ping_to_stream(stream) - end - - # Per SEP-2575, the server MUST NOT send notification types the client has not requested, - # and the acknowledgement only includes types the server actually supports - # (derived from its declared capabilities). - def honored_filter(filter) - capabilities = @server.capabilities - honored = {} - honored[:toolsListChanged] = true if filter[:toolsListChanged] && capability_flag?(capabilities, :tools, :listChanged) - honored[:promptsListChanged] = true if filter[:promptsListChanged] && capability_flag?(capabilities, :prompts, :listChanged) - honored[:resourcesListChanged] = true if filter[:resourcesListChanged] && capability_flag?(capabilities, :resources, :listChanged) - - subscriptions = filter[:resourceSubscriptions] - if capability_flag?(capabilities, :resources, :subscribe) && subscriptions.is_a?(Array) && !subscriptions.empty? - honored[:resourceSubscriptions] = subscriptions - end - - honored - end - - # Reads a nested capability flag tolerating both symbol and string keys, since user-supplied capability hashes arrive - # in either form. The flag that promises delivery (`listChanged` / `subscribe`) decides honoring, the same derivation - # `Server#discover` uses for its era-aware capability stripping; the mere presence of the primitive's capability is not enough. - def capability_flag?(capabilities, name, flag) - value = capabilities[name] || capabilities[name.to_s] - return false unless value.is_a?(Hash) - - !!(value[flag] || value[flag.to_s]) - end - - # Fans a notification out to every `subscriptions/listen` stream whose honored filter opted in to it, - # stamping the correlating `subscriptionId` into `_meta`. Matching against the honored filter - # (not the requested one) enforces the MUST NOT-send-unrequested-types rule. - def deliver_to_listen_subscriptions(method, params) - field = LISTEN_FILTER_FIELDS[method] - return if field.nil? && method != Methods::NOTIFICATIONS_RESOURCES_UPDATED - - # The matching snapshot is taken under `@mutex`, but stream writes happen outside it: - # a slow or stalled subscriber must not block the transport, matching the legacy delivery paths. - matched = @mutex.synchronize do - @listen_subscriptions.filter_map do |request_id, subscription| - # An inactive entry has not finished writing its acknowledgement yet; - # delivering to it would put a notification ahead of the acknowledgement. - next unless subscription[:active] - - hit = if field - subscription[:filter][field] - else - uris = subscription[:filter][:resourceSubscriptions] - uri = params.is_a?(Hash) ? params[:uri] || params["uri"] : nil - uris.is_a?(Array) && uris.include?(uri) - end - - [request_id, subscription] if hit - end - end - - matched.each do |request_id, subscription| - meta = { RequestEnvelope::SUBSCRIPTION_ID_META_KEY.to_sym => request_id } - notification_params = (params || {}).merge(_meta: meta) - notification = { jsonrpc: "2.0", method: method, params: notification_params } - - begin - # The per-stream write mutex orders this write against a concurrent graceful teardown: - # once teardown has marked the entry closed and written its `SubscriptionsListenResult`, - # a delivery that snapshotted the entry before the registry was cleared skips it instead - # of writing after the final message. - subscription[:write_mutex].synchronize do - next if subscription[:closed] - - send_to_stream(subscription[:stream], notification) - end - rescue *STREAM_WRITE_ERRORS => e - MCP.configuration.exception_reporter.call( - e, - { subscription_id: request_id, error: "Failed to send notification" }, - ) - remove_listen_subscription(request_id) - close_stream_safely(subscription[:stream]) - end - end - end - - def remove_listen_subscription(request_id) - @mutex.synchronize { @listen_subscriptions.delete(request_id) } - end - - # Graceful teardown (SEP-2575): each open listen stream receives its `SubscriptionsListenResult` response - # before the stream closes. - def teardown_listen_subscriptions - removed = @mutex.synchronize do - subscriptions = @listen_subscriptions.dup - @listen_subscriptions.clear - subscriptions - end - - removed.each do |request_id, subscription| - # Marking the entry closed and writing the result under the stream's write mutex orders - # this against in-flight deliveries: each one either lands before the result or observes - # `closed` and skips, keeping the graceful result the stream's final message. - subscription[:write_mutex].synchronize do - subscription[:closed] = true - - begin - send_to_stream(subscription[:stream], { - jsonrpc: "2.0", - id: request_id, - result: { - # `SubscriptionsListenResult` is served at the transport layer and never - # passes through the dispatch path, so the REQUIRED 2026-07-28 `resultType` is - # stamped at its construction site. - resultType: ResultType::COMPLETE, - _meta: { RequestEnvelope::SUBSCRIPTION_ID_META_KEY.to_sym => request_id }, - }, - }) - rescue *STREAM_WRITE_ERRORS - nil - end - end - close_stream_safely(subscription[:stream]) - end - end - - def header_mismatch_response(message, id) - json_rpc_error_response( - status: 400, - code: ErrorCodes::HEADER_MISMATCH, - message: "Header mismatch: #{message}", - id: id, - ) - end - - # Mirrors `MCP::Client::HTTP#encode_header_value`: a value wrapped as `=?base64??=` decodes to - # its original UTF-8 string; anything else is taken verbatim. Duplicated here because the client transport - # requires faraday, which servers do not depend on. - def decode_header_value(value) - match = value.match(/\A=\?base64\?(.*)\?=\z/m) - return value unless match - - match[1].unpack1("m0").force_encoding(Encoding::UTF_8) - rescue ArgumentError - value - end - - # Each modern request is self-contained: handlers run against an ephemeral per-request `ServerSession` locked to - # the modern era. The session carries a fresh unregistered `session_id` so notification and server-initiated-request plumbing - # keyed by session lookup degrades gracefully (delivery returns `false`) instead of broadcasting to unrelated legacy sessions - # via the `session_id.nil?` branch. - def modern_session - ServerSession.new(server: @server, transport: self, session_id: SecureRandom.uuid, era: :modern) - end - - def modern_http_status(response) - error_code = response.is_a?(Hash) ? response.dig(:error, :code) : nil - if error_code.nil? - 200 - elsif error_code == JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND - 404 - elsif MODERN_BAD_REQUEST_CODES.include?(error_code) - 400 - else - 200 - end - end - - def handle_post(request, body_string: nil) - required_types = @enable_json_response ? REQUIRED_POST_ACCEPT_TYPES_JSON : REQUIRED_POST_ACCEPT_TYPES_SSE - accept_error = validate_accept_header(request, required_types) - return accept_error if accept_error - - content_type_error = validate_content_type(request) - return content_type_error if content_type_error - - if body_string.nil? - body_string = read_bounded_body(request) - return payload_too_large_response if body_string.nil? - end - + body_string = request.body.read session_id = extract_session_id(request) - begin - body = parse_request_body(body_string) - rescue InvalidJsonError - return invalid_json_response - end + body = parse_request_body(body_string) + return body unless body.is_a?(Hash) # Error response - # Streamable HTTP (2025-11-25) requires a single JSON-RPC message object per POST. - # Batched/array bodies are not supported; reject with `-32600` instead of falling through to - # a malformed Rack response. - unless body.is_a?(Hash) - return invalid_request_response("Invalid Request: JSON-RPC body must be a single request object") - end - - # Header-primary routing sends sessionless modern traffic to `handle_modern` before this method runs, - # so a body carrying the modern `_meta` triple (SEP-2575) arrives here in two shapes only. - # Bound to a session under a dual-era header (2026-07-28), it is a lifecycle violation: the session - # already negotiated the legacy lifecycle via `initialize`, and a connection can never change eras - # (mirroring the stdio era lock). Otherwise the header is missing or names a stable-only version, - # which violates the header/body match requirement and would fall through the legacy path via - # the header default; reject that as a header mismatch. - if RequestEnvelope.modern?(body[:params]) - header_version = request.env["HTTP_MCP_PROTOCOL_VERSION"] - if header_version && MCP::Configuration.modern_protocol_version?(header_version) - return invalid_request_response( - "Invalid Request: the session already negotiated the legacy lifecycle via `initialize`", - request_id: body[:id], - ) - end - - return header_mismatch_response( - "MCP-Protocol-Version header is missing or legacy while the body carries the modern _meta envelope", - body[:id], - ) - end - - # The `MCP-Protocol-Version` header is only meaningful after negotiation, so on `initialize` - # the JSON-RPC body `params.protocolVersion` is authoritative and the header (if any) is ignored. - # This matches the TypeScript and Python SDKs. - # `server/discover` (SEP-2575) is likewise exempt: it is sessionless capability discovery that - # happens before (or instead of) negotiation. - unless initialize_request?(body) || discover_request?(body) - return missing_session_id_response if !@stateless && !session_id - - protocol_version_error = validate_protocol_version_header(request) - return protocol_version_error if protocol_version_error - end - - if initialize_request?(body) - if !@stateless && session_id - # An `initialize` request carrying an `Mcp-Session-Id` header is either a duplicate - # initialization attempt against a live session, or a retry against an unknown/expired - # one. In the live case, reject with `-32600` so the original session is not abandoned. - # In the unknown/expired case, return 404 so the client retries from scratch instead - # of silently inheriting a fresh session under the old ID. - return already_initialized_response(body[:id]) if session_active?(session_id) - - return session_not_found_response - end - - handle_initialization(request, body_string, body) + if body["method"] == "initialize" + handle_initialization(body_string, body) + elsif notification?(body) || response?(body) + handle_accepted else - # Ownership gate for every request against an existing session, applied uniformly to notifications, client responses, - # and regular requests. This covers write paths beyond tool calls - notably `notifications/cancelled`, which would - # otherwise let a stolen session ID cancel a victim's in-flight request. `initialize` is exempt (it establishes the session). - if !@stateless && session_id && !validate_session_request(request, session_id) - return forbidden_response - end - - if notification?(body) - # Reject a notification carrying an unknown or expired session ID instead of - # dispatching it against the shared `Server`. Mirrors the response and regular-request - # branches; without it a custom notification handler could run without a live session. - return session_not_found_response if !@stateless && !session_active?(session_id) - - dispatch_notification(body_string, session_id) - handle_accepted - elsif response?(body) - return session_not_found_response if !@stateless && !session_exists?(session_id) - - handle_response(body, session_id: session_id) - else - handle_regular_request(body_string, session_id, related_request_id: body[:id]) - end + handle_regular_request(body_string, session_id) end rescue StandardError => e MCP.configuration.exception_reporter.call(e, { request: body_string }) - json_rpc_error_response( - status: 500, - code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - message: "Internal server error", - ) + [500, { "Content-Type" => "application/json" }, [{ error: "Internal server error" }.to_json]] end def handle_get(request) @@ -1298,122 +140,58 @@ module MCP session_id = extract_session_id(request) return missing_session_id_response unless session_id - - error_response = validate_and_touch_session(session_id) - return error_response if error_response - return forbidden_response unless validate_session_request(request, session_id) - - protocol_version_error = validate_protocol_version_header(request) - return protocol_version_error if protocol_version_error - - return session_already_connected_response if get_session_stream(session_id) + return session_not_found_response unless session_exists?(session_id) setup_sse_stream(session_id) end def handle_delete(request) - success_response = [200, { "content-type" => "application/json" }, [{ success: true }.to_json]] + success_response = [200, { "Content-Type" => "application/json" }, [{ success: true }.to_json]] if @stateless - protocol_version_error = validate_protocol_version_header(request) - return protocol_version_error if protocol_version_error - # Stateless mode doesn't support sessions, so we can just return a success response return success_response end - return missing_session_id_response unless (session_id = extract_session_id(request)) - return session_not_found_response unless session_exists?(session_id) - return forbidden_response unless validate_session_request(request, session_id) + session_id = request.env["HTTP_MCP_SESSION_ID"] - protocol_version_error = validate_protocol_version_header(request) - return protocol_version_error if protocol_version_error + return [ + 400, + { "Content-Type" => "application/json" }, + [{ error: "Missing session ID" }.to_json], + ] unless session_id cleanup_session(session_id) - success_response end def cleanup_session(session_id) - session = @mutex.synchronize do + @mutex.synchronize do cleanup_session_unsafe(session_id) end - - if session - close_stream_safely(session[:get_sse_stream]) - close_post_request_streams(session) - end end - # Removes a session from `@sessions` and returns it. Does not close the stream. - # Callers must close the stream outside the mutex to avoid holding the lock during - # potentially blocking I/O. def cleanup_session_unsafe(session_id) - session = @sessions.delete(session_id) + session = @sessions[session_id] + return unless session - # Unblock threads waiting on pending responses for this session. - @pending_responses.each_value do |pending_response| - if pending_response[:session_id] == session_id - pending_response[:queue].push(:session_closed) - end - end - - session - end - - def cleanup_and_collect_stream(session_id, streams_to_close) - return unless (removed = cleanup_session_unsafe(session_id)) - - streams_to_close << removed[:get_sse_stream] - removed[:post_request_streams]&.each_value { |stream| streams_to_close << stream } - end - - def close_stream_safely(stream) - stream&.close - rescue StandardError - # Ignore close-related errors from already closed/broken streams. - end - - def close_post_request_streams(session) - return unless (post_request_streams = session[:post_request_streams]) - - post_request_streams.each_value do |stream| - close_stream_safely(stream) + begin + session[:stream]&.close + rescue + nil end + @sessions.delete(session_id) end def extract_session_id(request) request.env["HTTP_MCP_SESSION_ID"] end - # Session-ownership gate for requests against an existing session (the spec's session-binding guidance). - # The session ID alone is unguessable but not proof of ownership, so a stolen ID must not silently grant access. - # Two layers, both returning `false` to trigger a 403: - # - # - Built-in Origin consistency (defense in depth, not authentication): if the session recorded an `Origin` - # at `initialize` and this request carries a different one, reject. Both must be present to compare, - # so non-browser clients that send no `Origin` are unaffected. - # - The application-supplied `session_request_validator`, which can enforce true ownership when it has - # an authenticated principal. - def validate_session_request(request, session_id) - session = @mutex.synchronize { @sessions[session_id] } - return true unless session - - session_origin = session[:origin] - request_origin = request.env["HTTP_ORIGIN"] - return false if session_origin && request_origin && session_origin != request_origin - return @session_request_validator.call(request, session_id) if @session_request_validator - - true - end - def validate_accept_header(request, required_types) accept_header = request.env["HTTP_ACCEPT"] return not_acceptable_response(required_types) unless accept_header accepted_types = parse_accept_header(accept_header) - return if accepted_types.include?("*/*") - missing_types = required_types - accepted_types return not_acceptable_response(required_types) unless missing_types.empty? @@ -1422,228 +200,52 @@ module MCP def parse_accept_header(header) header.split(",").map do |part| - part.split(";").first.strip.downcase + part.split(";").first.strip end end - def validate_content_type(request) - content_type = request.env["CONTENT_TYPE"] - media_type = content_type&.split(";")&.first&.strip&.downcase - return if media_type == "application/json" - - json_rpc_error_response( - status: 415, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Unsupported Media Type: Content-Type must be application/json", - ) - end - def not_acceptable_response(required_types) - json_rpc_error_response( - status: 406, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Not Acceptable: Accept header must include #{required_types.join(" and ")}", - ) - end - - # Reads the request body with a hard byte cap so an unbounded POST cannot exhaust - # memory. A declared `Content-Length` over the cap is rejected - # without reading; the actual read is also bounded to one byte past the cap, so - # a missing or spoofed `Content-Length` (e.g. chunked transfer) is still caught. - # Returns `nil` when the body exceeds the cap. - def read_bounded_body(request) - content_length = request.content_length - return if content_length && content_length.to_i > @max_request_bytes - - body = request.body.read(@max_request_bytes + 1) - return "" if body.nil? - return if body.bytesize > @max_request_bytes - - body - end - - def payload_too_large_response - json_rpc_error_response( - status: 413, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Payload too large: request body exceeds #{@max_request_bytes} bytes", - ) + [ + 406, + { "Content-Type" => "application/json" }, + [{ error: "Not Acceptable: Accept header must include #{required_types.join(" and ")}" }.to_json], + ] end def parse_request_body(body_string) - # `max_nesting` bounds parse depth; a too-deep body raises `JSON::NestingError`, - # a subclass of `JSON::ParserError`, so it is caught below as a parse error. - JSON.parse(body_string, symbolize_names: true, max_nesting: MAX_JSON_NESTING) + JSON.parse(body_string) rescue JSON::ParserError, TypeError - raise InvalidJsonError - end - - def invalid_json_response - json_rpc_error_response( - status: 400, - code: JsonRpcHandler::ErrorCode::PARSE_ERROR, - message: "Parse error: Invalid JSON", - ) - end - - def initialize_request?(body) - body.is_a?(Hash) && body[:method] == Methods::INITIALIZE - end - - def discover_request?(body) - body.is_a?(Hash) && body[:method] == Methods::SERVER_DISCOVER - end - - # A version with no modern meaning, whose header can only accompany legacy traffic. - # A modern version's header (2026-07-28) can accompany either era's traffic - the handshake never negotiates it, - # but requests of an established legacy session may stamp it - so that value needs further disambiguation. - def stable_only_version?(version) - MCP::Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS.include?(version) && - !MCP::Configuration.modern_protocol_version?(version) - end - - # Era sniff for a sessionless POST under a dual-era header version: only an `initialize` body - # WITHOUT the modern `_meta` envelope is legacy-distinctive. An `initialize` carrying - # the envelope comes from a modern client naming a method its lifecycle removed, so it stays - # on the modern path and answers with -32601/404 (SEP-2575). - # Unparsable or non-object bodies go to the modern path, whose error responses cover them. - def legacy_handshake_body?(body_string) - body = parse_request_body(body_string) - return false unless initialize_request?(body) - - !RequestEnvelope.modern?(body[:params]) - rescue InvalidJsonError - false - end - - def validate_protocol_version_header(request) - header_value = request.env["HTTP_MCP_PROTOCOL_VERSION"] || MCP::Configuration::DEFAULT_NEGOTIATED_PROTOCOL_VERSION - return if MCP::Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS.include?(header_value) - - supported = MCP::Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS.join(", ") - json_rpc_error_response( - status: 400, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Bad Request: Unsupported protocol version: #{header_value}. Supported versions: #{supported}", - ) - end - - def json_rpc_error_response(status:, code:, message:, data: nil, id: nil) - error = { code: code, message: message } - error[:data] = data if data - body = { jsonrpc: "2.0", id: id, error: error } - [status, { "content-type" => "application/json" }, [body.to_json]] + [400, { "Content-Type" => "application/json" }, [{ error: "Invalid JSON" }.to_json]] end def notification?(body) - !body[:id] && !!body[:method] - end - - # Dispatches a client-originated notification (e.g. `notifications/cancelled`, - # `notifications/initialized`) through the server so it can update session state. - def dispatch_notification(body_string, session_id) - server_session = nil - if @stateless - server_session = ephemeral_session - elsif session_id - @mutex.synchronize do - session = @sessions[session_id] - server_session = session[:server_session] if session - end - end - - dispatch_handle_json(body_string, server_session) - rescue => e - MCP.configuration.exception_reporter.call(e, { error: "Failed to dispatch notification" }) + !body["id"] && !!body["method"] end def response?(body) - !!body[:id] && !body[:method] + !!body["id"] && !body["method"] end - # Verifies that the response came from the expected session to prevent - # cross-session response injection if request IDs are ever leaked. - def handle_response(body, session_id:) - request_id = body[:id] - @mutex.synchronize do - if (pending_response = @pending_responses[request_id]) && pending_response[:session_id] == session_id - if body.key?(:error) - error = body[:error] - pending_response[:queue].push(error: { code: error[:code], message: error[:message] }) - else - pending_response[:queue].push(body[:result]) - end - end - end - - handle_accepted - end - - def handle_initialization(request, body_string, body) + def handle_initialization(body_string, body) session_id = nil - if @stateless - server_session = ephemeral_session - else + unless @stateless session_id = SecureRandom.uuid - server_session = ServerSession.new(server: @server, transport: self, session_id: session_id) - - # Cap the concurrent session count so an `initialize` flood cannot retain unbounded sessions until memory is exhausted. - # The check and insert share the mutex so concurrent initializes cannot race past the limit. - reclaimed = [] - inserted = @mutex.synchronize do - # When at the cap, first reclaim slots held by already-expired sessions the 60s reaper has not yet collected, - # so the cap rejects only when genuinely full rather than up to a reaper interval after sessions expired. - if @max_sessions && @sessions.size >= @max_sessions - @sessions.each_key.select { |id| session_expired?(@sessions[id]) }.each do |id| - cleanup_and_collect_stream(id, reclaimed) - end - end - - next false if @max_sessions && @sessions.size >= @max_sessions + @mutex.synchronize do @sessions[session_id] = { - get_sse_stream: nil, - server_session: server_session, - last_active_at: Process.clock_gettime(Process::CLOCK_MONOTONIC), - # Captured for the built-in Origin-consistency defense in `validate_session_request`. - # Not authentication. - origin: request.env["HTTP_ORIGIN"], + stream: nil, } - true end - - reclaimed.each { |stream| close_stream_safely(stream) } - return too_many_sessions_response unless inserted end - response = server_session.handle_json(body_string) - - # `initialize_request?` matches on the method alone, so an `initialize` sent without - # an id (framed as a notification) reaches here. `Server#init` marks the session initialized, - # but JSON-RPC emits no response for an id-less request, so `response` is nil. - # Returning `[200, ..., [nil]]` would place nil in the Rack body (which the web server cannot serialize), - # and the session would be retained since it is marked initialized. Discard the orphaned session - # and ack with 202, mirroring the nil-response handling in a regular request. - if response.nil? - cleanup_session(session_id) if session_id - return handle_accepted - end - - # If `Server#init` produced an error response (e.g., malformed JSON-RPC envelope), - # `mark_initialized!` was never called. Discard the orphaned session and omit - # the `Mcp-Session-Id` header so the client retries from a clean state instead of - # reusing a never-initialized ID that would later look like a duplicate `initialize`. - if session_id && !server_session.initialized? - cleanup_session(session_id) - session_id = nil - end + response = @server.handle_json(body_string) headers = { - "content-type" => "application/json", + "Content-Type" => "application/json", } - headers["mcp-session-id"] = session_id if session_id + headers["Mcp-Session-Id"] = session_id if session_id [200, headers, [response]] end @@ -1652,333 +254,91 @@ module MCP [202, {}, []] end - def too_many_sessions_response - json_rpc_error_response( - status: 503, - code: JsonRpcHandler::ErrorCode::INTERNAL_ERROR, - message: "Service unavailable: maximum concurrent sessions (#{@max_sessions}) reached", - ) - end - - def handle_regular_request(body_string, session_id, related_request_id: nil) - server_session = nil - - if @stateless - server_session = ephemeral_session - elsif session_id - error_response = validate_and_touch_session(session_id) - return error_response if error_response - - @mutex.synchronize do - session = @sessions[session_id] - server_session = session[:server_session] if session + def handle_regular_request(body_string, session_id) + unless @stateless + # If session ID is provided, but not in the sessions hash, return an error + if session_id && !@sessions.key?(session_id) + return [400, { "Content-Type" => "application/json" }, [{ error: "Invalid session ID" }.to_json]] end end - # `Server` refuses a duplicate id as well, but only once the request reaches it. The SSE branch below - # registers this request's stream under that id first, so without this check the colliding request - # would take over the routing entry for the moment it takes to be rejected, and its `ensure` would then - # clear the entry the original request still needs. - if related_request_id && server_session&.in_flight?(related_request_id) - return request_id_conflict_response - end + response = @server.handle_json(body_string) || "" - if session_id && !@stateless && !@enable_json_response - handle_request_with_sse_response(body_string, session_id, server_session, related_request_id: related_request_id) + # Stream can be nil since stateless mode doesn't retain streams + stream = get_session_stream(session_id) if session_id + + if stream + send_response_to_stream(stream, response, session_id) + elsif response.nil? && notification_request?(body_string) + [202, { "Content-Type" => "application/json" }, [response]] else - response = dispatch_handle_json(body_string, server_session) - - # `Server#handle_json` returns `nil` when cancellation has suppressed the JSON-RPC response per spec. - # Mirror the notification path and ack with 202 instead of returning a 200 with a `nil` Rack body, - # which would produce an empty body the client cannot parse as JSON. - return handle_accepted if response.nil? - - [200, { "content-type" => "application/json" }, [response]] + [200, { "Content-Type" => "application/json" }, [response]] end end - # Returns the POST response as an SSE stream so the server can send - # JSON-RPC requests and notifications during request processing. - # https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#sending-messages-to-the-server - def handle_request_with_sse_response(body_string, session_id, server_session, related_request_id: nil) - body = proc do |stream| - @mutex.synchronize do - session = @sessions[session_id] - if session && related_request_id - session[:post_request_streams] ||= {} - - # Claim the id only while it is free. `handle_regular_request` already refused the colliding request, - # so reaching an occupied slot means a race got past that check; leaving the first stream in place keeps - # its messages going where they belong. - session[:post_request_streams][related_request_id] ||= stream - end - end - - begin - response = dispatch_handle_json(body_string, server_session) - - send_to_stream(stream, response) if response - ensure - if related_request_id - @mutex.synchronize do - session = @sessions[session_id] - # Only retire our own registration: a request that never claimed the id, or one whose claim has - # already been replaced, must not unregister the stream that owns it. - registered = session&.dig(:post_request_streams, related_request_id) - - session[:post_request_streams].delete(related_request_id) if registered.equal?(stream) - end - end - - begin - stream.close - rescue StandardError - # Ignore close-related errors from already closed/broken streams. - end - end - end - - [200, SSE_HEADERS.dup, body] - end - - # Returns the SSE stream available for server-to-client messages. - # When `related_request_id` is given, returns only the POST response - # stream for that request (no fallback to GET SSE). This prevents - # request-scoped messages from leaking to the wrong stream. - # When `related_request_id` is nil, returns the GET SSE stream. - def active_stream(session, related_request_id: nil) - if related_request_id - session.dig(:post_request_streams, related_request_id) - else - session[:get_sse_stream] - end - end - - def dispatch_handle_json(body_string, server_session) - if server_session - server_session.handle_json(body_string) - else - @server.handle_json(body_string) - end - end - - def validate_and_touch_session(session_id) - removed = nil - - response = @mutex.synchronize do - next session_not_found_response unless (session = @sessions[session_id]) - next unless @session_idle_timeout - - if session_expired?(session) - removed = cleanup_session_unsafe(session_id) - next session_not_found_response - end - - session[:last_active_at] = Process.clock_gettime(Process::CLOCK_MONOTONIC) - nil - end - - if removed - close_stream_safely(removed[:get_sse_stream]) - - removed[:post_request_streams]&.each_value do |stream| - close_stream_safely(stream) - end - end - - response + def notification_request?(body_string) + body = parse_request_body(body_string) + body.is_a?(Hash) && body["method"].start_with?("notifications/") end def get_session_stream(session_id) - @mutex.synchronize { @sessions[session_id]&.fetch(:get_sse_stream, nil) } + @mutex.synchronize { @sessions[session_id]&.fetch(:stream, nil) } + end + + def send_response_to_stream(stream, response, session_id) + message = JSON.parse(response) + send_to_stream(stream, message) + [200, { "Content-Type" => "application/json" }, [{ accepted: true }.to_json]] + rescue IOError, Errno::EPIPE => e + MCP.configuration.exception_reporter.call( + e, + { session_id: session_id, error: "Stream closed during response" }, + ) + cleanup_session(session_id) + [200, { "Content-Type" => "application/json" }, [response]] end def session_exists?(session_id) @mutex.synchronize { @sessions.key?(session_id) } end - # Each stateless POST is self-contained (SEP-2567): handlers run against an ephemeral per-request `ServerSession` - # so client info, logging level, and initialized state never leak onto the shared `Server` instance or across concurrent requests. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2567 - def ephemeral_session - ServerSession.new(server: @server, transport: self, session_id: nil) - end - - # Returns true iff a session exists and is not past its idle timeout. Expired sessions - # are evicted as a side effect so a live request never observes a zombie session that - # the reaper hasn't yet pruned. Does NOT update `last_active_at`; callers that are - # rejecting a request must not extend the session's lifetime. - def session_active?(session_id) - removed = nil - active = @mutex.synchronize do - next false unless (session = @sessions[session_id]) - - if session_expired?(session) - removed = cleanup_session_unsafe(session_id) - next false - end - - true - end - - if removed - close_stream_safely(removed[:get_sse_stream]) - close_post_request_streams(removed) - end - - active - end - - # Per MCP 2025-11-25, servers MUST validate the `Origin` header and SHOULD bind only to localhost - # to prevent DNS rebinding attacks against locally bound MCP servers. Protection is on by default; - # pass `dns_rebinding_protection: false` to disable it (e.g. when an upstream proxy or middleware already - # performs the check). The `Host` header is validated against the loopback defaults plus `allowed_hosts:`, - # and the `Origin` header, when present, must be same-origin or in `allowed_origins:`. - def validate_dns_rebinding(request) - return unless @dns_rebinding_protection - - validate_host(request) || validate_origin(request) - end - - # Rejects a rebound `Host` (e.g. `evil.example.com` re-pointed at 127.0.0.1). - # A request without a `Host` header (e.g. HTTP/1.0) is allowed; the rebinding vector this guards against always carries one. - def validate_host(request) - host = request.env["HTTP_HOST"] - return if host.nil? - - # An `allowed_hosts:` entry matches either the bare host name (any port) - # or the full `host:port` value, so both `"app.example.com"` and - # `"app.example.com:8443"` can be configured. - normalized = host.downcase - return if @allowed_hosts.include?(request_hostname(normalized)) || @allowed_hosts.include?(normalized) - - forbidden_response("Forbidden: Invalid Host header") - end - - # A request without an `Origin` header (typical for non-browser MCP clients) is allowed. A browser cross-origin request is - # rejected unless the origin is same-origin or explicitly allow-listed via `allowed_origins:`. - def validate_origin(request) - origin = request.env["HTTP_ORIGIN"] - return if origin.nil? - return if same_origin?(origin, request) - return if @allowed_origins.include?(origin.downcase) - - forbidden_response("Forbidden: Invalid Origin header") - end - - # Extracts the host name from a `Host` header value, stripping any port and IPv6 brackets - # (`[::1]:8080` becomes `::1`, `127.0.0.1:8080` becomes `127.0.0.1`). - def request_hostname(host) - return host[/\A\[([^\]]+)\]/, 1] if host.start_with?("[") - - host.split(":").first - end - - # Compares the `Origin` authority (host:port) against the request's own `Host`. - # Scheme is not compared (the `Host` header carries none, and `request.scheme` is unreliable behind proxies), - # but the `Origin`'s scheme is used to drop a redundant default port (`:80` for http, `:443` for https) from - # both sides so `http://example.com` matches `Host: example.com:80`. Comparison is case-insensitive. - def same_origin?(origin, request) - host = request.env["HTTP_HOST"] - return false if host.nil? - - normalized = origin.downcase - default_port = normalized.start_with?("https://") ? ":443" : ":80" - authority = normalized.sub(%r{\Ahttps?://}, "") - - authority.delete_suffix(default_port) == host.downcase.delete_suffix(default_port) - end - - def forbidden_response(message = "Forbidden: session request validation failed") - json_rpc_error_response( - status: 403, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: message, - ) - end - def method_not_allowed_response - json_rpc_error_response( - status: 405, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Method not allowed", - ) + [405, { "Content-Type" => "application/json" }, [{ error: "Method not allowed" }.to_json]] end def missing_session_id_response - json_rpc_error_response( - status: 400, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Missing session ID", - ) + [400, { "Content-Type" => "application/json" }, [{ error: "Missing session ID" }.to_json]] end def session_not_found_response - json_rpc_error_response( - status: 404, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Session not found", - ) - end - - def already_initialized_response(request_id) - invalid_request_response("Invalid Request: Server already initialized", request_id: request_id) - end - - def invalid_request_response(message, request_id: nil) - body = { - jsonrpc: "2.0", - id: request_id, - error: { - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: message, - }, - } - [400, { "content-type" => "application/json" }, [body.to_json]] - end - - def session_already_connected_response - json_rpc_error_response( - status: 409, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Conflict: Only one SSE stream is allowed per session", - ) - end - - # The POST counterpart of the GET conflict above. A request id already in flight cannot be given - # a stream of its own, because the id is what routes request-scoped messages back. - def request_id_conflict_response - json_rpc_error_response( - status: 409, - code: JsonRpcHandler::ErrorCode::INVALID_REQUEST, - message: "Conflict: Request id is already in flight for this session", - ) + [404, { "Content-Type" => "application/json" }, [{ error: "Session not found" }.to_json]] end def setup_sse_stream(session_id) body = create_sse_body(session_id) - [200, SSE_HEADERS.dup, body] + headers = { + "Content-Type" => "text/event-stream", + "Cache-Control" => "no-cache", + "Connection" => "keep-alive", + } + + [200, headers, body] end def create_sse_body(session_id) proc do |stream| - stored = store_stream_for_session(session_id, stream) - start_keepalive_thread(session_id) if stored + store_stream_for_session(session_id, stream) + start_keepalive_thread(session_id) end end def store_stream_for_session(session_id, stream) @mutex.synchronize do - session = @sessions[session_id] - if session && !session[:get_sse_stream] - session[:get_sse_stream] = stream + if @sessions[session_id] + @sessions[session_id][:stream] = stream else - # Either session was removed, or another request already established a stream. stream.close - # `stream.close` may return a truthy value depending on the stream class. - # Explicitly return nil to guarantee a falsy return for callers. - nil end end end @@ -1997,32 +357,22 @@ module MCP end def session_active_with_stream?(session_id) - @mutex.synchronize { @sessions.key?(session_id) && @sessions[session_id][:get_sse_stream] } + @mutex.synchronize { @sessions.key?(session_id) && @sessions[session_id][:stream] } end def send_keepalive_ping(session_id) - # Resolve the stream under the lock, then write outside it so a stalled reader - # cannot block every other session on `@mutex`. - stream = @mutex.synchronize do - session = @sessions[session_id] - session && session[:get_sse_stream] + @mutex.synchronize do + if @sessions[session_id] && @sessions[session_id][:stream] + send_ping_to_stream(@sessions[session_id][:stream]) + end end - return unless stream - - send_ping_to_stream(stream) - rescue *STREAM_WRITE_ERRORS => e + rescue IOError, Errno::EPIPE => e MCP.configuration.exception_reporter.call( e, { session_id: session_id, error: "Stream closed" }, ) raise # Re-raise to exit the keepalive loop end - - def session_expired?(session) - return false unless @session_idle_timeout - - Process.clock_gettime(Process::CLOCK_MONOTONIC) - session[:last_active_at] > @session_idle_timeout - end end end end diff --git a/lib/mcp/server_context.rb b/lib/mcp/server_context.rb deleted file mode 100644 index 33b2075..0000000 --- a/lib/mcp/server_context.rb +++ /dev/null @@ -1,259 +0,0 @@ -# frozen_string_literal: true - -module MCP - class ServerContext - attr_reader :cancellation - - # The SEP-2575 per-request envelope (`MCP::RequestEnvelope`) when the request was classified as modern; - # `nil` on legacy requests. - attr_reader :envelope - - # SEP-2322 multi round-trip retry fields, present when the client re-issued the request after - # an `input_required` result: `input_responses` maps the keys of the earlier `inputRequests` to - # the client's answers, and `request_state` is the opaque continuation string echoed back byte-exactly. - # Both are `nil` on a first-round request. Only handlers that opt in to `server_context:` can read them - # (the same access model as the envelope readers). - attr_reader :input_responses, :request_state - - def initialize(context, progress:, notification_target:, related_request_id: nil, cancellation: nil, envelope: nil, - input_responses: nil, request_state: nil) - @context = context - @progress = progress - @notification_target = notification_target - @related_request_id = related_request_id - @cancellation = cancellation - @envelope = envelope - @input_responses = input_responses - @request_state = request_state - end - - # Reads one entry of {#input_responses} by its `inputRequests` key, tolerating symbol or string keys. - def input_response(key) - return unless @input_responses.is_a?(Hash) - - value = @input_responses[key.to_sym] - value.nil? ? @input_responses[key.to_s] : value - end - - def cancelled? - !!@cancellation&.cancelled? - end - - def raise_if_cancelled! - @cancellation&.raise_if_cancelled! - end - - # Whether the current request follows the stateless modern lifecycle (SEP-2575). - def modern? - !@envelope.nil? - end - - # Client identity for the current request. Modern requests carry it in the `_meta` envelope; - # legacy sessions fall back to the state stored by `initialize`. The envelope always wins - # because servers MUST NOT infer identity from prior requests. - def client_info - return @envelope.client_info if @envelope - - @notification_target.client if @notification_target.respond_to?(:client) - end - - # Client capabilities for the current request, with the same envelope-first resolution as {#client_info}. - def client_capabilities - return @envelope.client_capabilities if @envelope - - @notification_target.client_capabilities if @notification_target.respond_to?(:client_capabilities) - end - - # The protocol version the current request was made with. `nil` on legacy requests, - # where the version is a session-level negotiation result rather than per-request data. - def protocol_version - @envelope&.protocol_version - end - - # Guards the current request on a declared client capability (SEP-2575). `path` names nested capability keys, - # e.g. `require_client_capability!(:elicitation, :form)`. Raises `Server::MissingRequiredClientCapabilityError` - # (JSON-RPC error `-32021` with `data: { requiredCapabilities: ... }`) when the capability was not declared. - def require_client_capability!(*path) - raise ArgumentError, "at least one capability key is required" if path.empty? - - declared = client_capabilities - value = path.reduce(declared) do |acc, key| - break unless acc.is_a?(Hash) - - symbol_value = acc[key.to_sym] - symbol_value.nil? ? acc[key.to_s] : symbol_value - end - return unless value.nil? - - required = path.reverse.inject({}) { |acc, key| { key.to_sym => acc } } - raise Server::MissingRequiredClientCapabilityError, required - end - - # Reports progress for the current tool operation. - # The notification is automatically scoped to the originating session. - # - # @param progress [Numeric] Current progress value. - # @param total [Numeric, nil] Total expected value. - # @param message [String, nil] Human-readable status message. - def report_progress(progress, total: nil, message: nil) - @progress.report(progress, total: total, message: message) - end - - # Sends a log message notification scoped to the originating session. - # - # @param data [Object] The log data to send. - # @param level [String] Log level (e.g., `"debug"`, `"info"`, `"error"`). - # @param logger [String, nil] Logger name. - # @deprecated MCP Logging (`logging/setLevel` and `notifications/message`) - # is deprecated as of MCP protocol version 2026-07-28 (SEP-2577). - # Use stderr or OpenTelemetry instead. - def notify_log_message(data:, level:, logger: nil) - return unless @notification_target - - # Modern requests opt in to logging per request (SEP-2575): without `io.modelcontextprotocol/logLevel` in `_meta`, - # the server MUST NOT send any `notifications/message` for the request, and an insufficient level drops - # the message the same way. Session- or server-level gating still applies downstream on delegation. - if @envelope - threshold = @envelope.log_level && LoggingMessageNotification.new(level: @envelope.log_level) - return unless threshold&.valid_level? && threshold.should_notify?(level) - end - - @notification_target.notify_log_message(data: data, level: level, logger: logger, related_request_id: @related_request_id) - end - - # Sends a resource updated notification scoped to the originating session. - # - # @param uri [String] The URI of the updated resource. - def notify_resources_updated(uri:) - return unless @notification_target - - @notification_target.notify_resources_updated(uri: uri) - end - - # Delegates to the session so the request is scoped to the originating client. - # The originating request id is stamped as `related_request_id`, satisfying - # SEP-2260's requirement that server-to-client requests be associated with - # the client request being processed. - # @deprecated MCP Roots (`roots/list` and - # `notifications/roots/list_changed`) is deprecated as of MCP protocol - # version 2026-07-28 (SEP-2577). Use tool parameters, resource URIs, - # server configuration, or environment variables instead. - def list_roots(timeout: nil) - if @notification_target.respond_to?(:list_roots) - @notification_target.list_roots(related_request_id: @related_request_id, **timeout_kwarg(timeout)) - else - raise NoMethodError, "undefined method 'list_roots' for #{self}" - end - end - - # Sends a `ping` request to the originating client to verify it is still responsive. - # Per the MCP spec, the client MUST respond promptly with an empty result. - # - # @return [Hash] An empty hash on success. - # @raise [Server::ValidationError] If the response `result` is not a Hash. - # @raise [NoMethodError] If the session does not support sending pings. - # - # @example - # def self.call(server_context:) - # server_context.ping # => {} - # # ... - # end - # - # @see https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/ping - def ping(timeout: nil) - if @notification_target.respond_to?(:ping) - @notification_target.ping(related_request_id: @related_request_id, **timeout_kwarg(timeout)) - else - raise NoMethodError, "undefined method 'ping' for #{self}" - end - end - - # Delegates to the session so the request is scoped to the originating client. - # Falls back to `@context` (via `method_missing`) when `@notification_target` - # does not support sampling. - # - # The originating request id is stamped as `related_request_id` and cannot be - # overridden by callers (the literal keyword after `**kwargs` wins), - # satisfying SEP-2260's requirement that server-to-client requests be - # associated with the client request being processed. - # @deprecated MCP Sampling (`sampling/createMessage`) is deprecated as of - # MCP protocol version 2026-07-28 (SEP-2577). Use direct LLM provider - # APIs instead. - def create_sampling_message(**kwargs) - if @notification_target.respond_to?(:create_sampling_message) - @notification_target.create_sampling_message(**kwargs, related_request_id: @related_request_id) - elsif @context.respond_to?(:create_sampling_message) - @context.create_sampling_message(**kwargs, related_request_id: @related_request_id) - else - raise NoMethodError, "undefined method 'create_sampling_message' for #{self}" - end - end - - # Delegates to the session so the request is scoped to the originating client. - # Falls back to `@context` (via `method_missing`) when `@notification_target` - # does not support elicitation. - # The originating request id is stamped as a non-overridable - # `related_request_id`, as with `create_sampling_message` (SEP-2260). - def create_form_elicitation(**kwargs) - if @notification_target.respond_to?(:create_form_elicitation) - @notification_target.create_form_elicitation(**kwargs, related_request_id: @related_request_id) - elsif @context.respond_to?(:create_form_elicitation) - @context.create_form_elicitation(**kwargs, related_request_id: @related_request_id) - else - raise NoMethodError, "undefined method 'create_form_elicitation' for #{self}" - end - end - - # Delegates to the session so the request is scoped to the originating client. - # Falls back to `@context` when `@notification_target` does not support URL mode elicitation. - # The originating request id is stamped as a non-overridable `related_request_id`, - # as with `create_sampling_message` (SEP-2260). - def create_url_elicitation(**kwargs) - if @notification_target.respond_to?(:create_url_elicitation) - @notification_target.create_url_elicitation(**kwargs, related_request_id: @related_request_id) - elsif @context.respond_to?(:create_url_elicitation) - @context.create_url_elicitation(**kwargs, related_request_id: @related_request_id) - else - raise NoMethodError, "undefined method 'create_url_elicitation' for #{self}" - end - end - - # Delegates to the session so the notification is scoped to the originating client. - def notify_elicitation_complete(**kwargs) - if @notification_target.respond_to?(:notify_elicitation_complete) - @notification_target.notify_elicitation_complete(**kwargs) - elsif @context.respond_to?(:notify_elicitation_complete) - @context.notify_elicitation_complete(**kwargs) - else - raise NoMethodError, "undefined method 'notify_elicitation_complete' for #{self}" - end - end - - # Forward arguments explicitly with `*args, **kwargs, &block` rather than the `...` forwarding syntax. - # The gem supports Ruby 2.7.0 (see `required_ruby_version`), but RuboCop's Parser backend only runs on Ruby 2.7.8, - # so leading-argument forwarding like `def method_missing(name, ...)` is allowed by the linter even though it - # raises a `SyntaxError` on Ruby 2.7.0 through 2.7.2 (it was added in Ruby 2.7.3). Explicit forwarding keeps - # this method loadable on Ruby 2.7.0. - def method_missing(name, *args, **kwargs, &block) - if @context.respond_to?(name) - @context.public_send(name, *args, **kwargs, &block) - else - super - end - end - - def respond_to_missing?(name, include_private = false) - @context.respond_to?(name) || super - end - - private - - # An omitted `timeout:` is not forwarded at all, so the delegated call keeps the shape it had - # before per-request timeouts existed. A notification target that predates the keyword - # (a custom object standing in for a session) keeps working until a caller actually asks for a timeout, - # and the transport applies its own default in that case. - def timeout_kwarg(timeout) - timeout.nil? ? {} : { timeout: timeout } - end - end -end diff --git a/lib/mcp/server_session.rb b/lib/mcp/server_session.rb deleted file mode 100644 index cfee2ab..0000000 --- a/lib/mcp/server_session.rb +++ /dev/null @@ -1,392 +0,0 @@ -# frozen_string_literal: true - -require_relative "cancellation" -require_relative "methods" - -module MCP - # Holds per-connection state for a single client session. - # Created by the transport layer; delegates request handling to the shared `Server`. - class ServerSession - ERAS = [:legacy, :modern].freeze - - attr_reader :session_id, :client, :logging_message_notification, :protocol_version - - # Connection-era lock of the dual-era serving model (SEP-2575): `nil` until the first era-distinctive message succeeds, - # then `:legacy` or `:modern` for the connection's lifetime. Modern-era transports construct their per-request sessions - # with `era: :modern` up front. - attr_reader :era - - def initialize(server:, transport:, session_id: nil, era: nil) - validate_era!(era) if era - - @server = server - @transport = transport - @session_id = session_id - @era = era - @client = nil - @client_capabilities = nil - @logging_message_notification = nil - @protocol_version = nil - @in_flight = {} - @in_flight_mutex = Mutex.new - @initialized = false - end - - # Whether `initialize` has already completed for this session. - def initialized? - @initialized - end - - # Called by `Server#init` after a successful `initialize` response, so subsequent - # `initialize` requests on the same session can be rejected per MCP spec - # (the initialization phase MUST be the first interaction). - def mark_initialized!(protocol_version: nil) - @initialized = true - @protocol_version = protocol_version - # A successful `initialize` is the legacy-distinctive message of the dual-era serving model (SEP-2575), - # so it also locks the connection era. - @era ||= :legacy - end - - # One-shot era lock. Locking the already-locked era is a no-op; flipping an established era raises, - # because a connection can never change eras. - def lock_era!(era) - validate_era!(era) - return if @era == era - raise "Session era already locked to #{@era}" if @era - - @era = era - end - - # Registers a `Cancellation` token for an in-flight request, or returns `nil` when `request_id` is already in flight. - # The request id is the only key that routes request-scoped notifications, server-to-client requests, - # and `notifications/cancelled` back to the request that caused them, so a second live request under the same id - # has no destination of its own. Rather than let the newcomer displace the registration, report the collision - # and leave the first request intact; the caller turns that into an Invalid Request. - def register_in_flight(request_id) - return if request_id.nil? - - cancellation = Cancellation.new(request_id: request_id) - registered = @in_flight_mutex.synchronize do - next false if @in_flight.key?(request_id) - - @in_flight[request_id] = cancellation - true - end - - registered ? cancellation : nil - end - - # Removes an in-flight registration. Passing the `Cancellation` that `register_in_flight` returned removes - # the entry only while it is still that one, so a request can never evict a registration it does not own. - def unregister_in_flight(request_id, cancellation: nil) - return if request_id.nil? - - @in_flight_mutex.synchronize do - next if cancellation && !@in_flight[request_id].equal?(cancellation) - - @in_flight.delete(request_id) - end - end - - # Whether `request_id` is currently in flight, so a transport can refuse a colliding request - # before registering any state of its own for it. - def in_flight?(request_id) - !lookup_in_flight(request_id).nil? - end - - def lookup_in_flight(request_id) - @in_flight_mutex.synchronize { @in_flight[request_id] } - end - - # Flips the `Cancellation` for a matching in-flight request received from the peer. - # Silently ignores unknown IDs per MCP spec (cancellation utilities, item 5). - def cancel_incoming(request_id:, reason: nil) - cancellation = lookup_in_flight(request_id) - cancellation&.cancel(reason: reason) - end - - # Sends `notifications/cancelled` to the peer for a previously-issued request. - # Also unblocks any transport-level `send_request` waiting on a response for `request_id`. - def cancel_request(request_id:, reason: nil) - params = { requestId: request_id } - params[:reason] = reason if reason - send_to_transport(Methods::NOTIFICATIONS_CANCELLED, params) - - if @transport.respond_to?(:cancel_pending_request) - @transport.cancel_pending_request(request_id, reason: reason) - end - rescue => e - MCP.configuration.exception_reporter.call(e, { notification: "cancelled", request_id: request_id }) - end - - def handle(request) - @server.handle(request, session: self) - end - - def handle_json(request_json) - @server.handle_json(request_json, session: self) - end - - # Called by `Server#init` during the initialization handshake. - def store_client_info(client:, capabilities: nil) - @client = client - @client_capabilities = capabilities - end - - # Called by `Server#configure_logging_level`. - def configure_logging(logging_message_notification) - @logging_message_notification = logging_message_notification - end - - # Returns per-session client capabilities, falling back to global. - def client_capabilities - @client_capabilities || @server.client_capabilities - end - - # Sends a `roots/list` request scoped to this session. - # - # Per SEP-2260, the request must be associated with an originating client - # request; prefer `server_context.list_roots` inside a handler, which stamps - # the association automatically. - # @deprecated MCP Roots (`roots/list` and - # `notifications/roots/list_changed`) is deprecated as of MCP protocol - # version 2026-07-28 (SEP-2577). Use tool parameters, resource URIs, - # server configuration, or environment variables instead. - def list_roots(related_request_id: nil, timeout: nil) - warn_unassociated_request(__method__, related_request_id) - - unless client_capabilities&.dig(:roots) - raise "Client does not support roots." - end - - send_to_transport_request(Methods::ROOTS_LIST, nil, related_request_id: related_request_id, timeout: timeout) - end - - # Sends a `ping` request scoped to this session. - def ping(related_request_id: nil, timeout: nil) - result = send_to_transport_request(Methods::PING, nil, related_request_id: related_request_id, timeout: timeout) - raise Server::ValidationError, "Response validation failed: invalid `result`" unless result.is_a?(Hash) - - result - end - - # Sends a `sampling/createMessage` request scoped to this session. - # - # Per SEP-2260, the request must be associated with an originating client - # request; prefer `server_context.create_sampling_message` inside a handler, - # which stamps the association automatically. - # @deprecated MCP Sampling (`sampling/createMessage`) is deprecated as of - # MCP protocol version 2026-07-28 (SEP-2577). Use direct LLM provider - # APIs instead. - def create_sampling_message(related_request_id: nil, timeout: nil, **kwargs) - warn_unassociated_request(__method__, related_request_id) - - params = @server.build_sampling_params(client_capabilities, **kwargs) - send_to_transport_request( - Methods::SAMPLING_CREATE_MESSAGE, - params, - related_request_id: related_request_id, - timeout: timeout, - ) - end - - # Sends an `elicitation/create` request (form mode) scoped to this session. - # - # Per SEP-2260, the request must be associated with an originating client - # request; prefer `server_context.create_form_elicitation` inside a handler, - # which stamps the association automatically. - def create_form_elicitation(message:, requested_schema:, related_request_id: nil, timeout: nil) - warn_unassociated_request(__method__, related_request_id) - - unless client_capabilities&.dig(:elicitation) - raise "Client does not support elicitation. " \ - "The client must declare the `elicitation` capability during initialization." - end - - params = { mode: "form", message: message, requestedSchema: requested_schema } - send_to_transport_request( - Methods::ELICITATION_CREATE, - params, - related_request_id: related_request_id, - timeout: timeout, - ) - end - - # Sends an `elicitation/create` request (URL mode) scoped to this session. - # - # Per SEP-2260, the request must be associated with an originating client - # request; prefer `server_context.create_url_elicitation` inside a handler, - # which stamps the association automatically. - def create_url_elicitation(message:, url:, elicitation_id:, related_request_id: nil, timeout: nil) - warn_unassociated_request(__method__, related_request_id) - - unless client_capabilities&.dig(:elicitation, :url) - raise "Client does not support URL mode elicitation. " \ - "The client must declare the `elicitation.url` capability during initialization." - end - - params = { mode: "url", message: message, url: url, elicitationId: elicitation_id } - send_to_transport_request( - Methods::ELICITATION_CREATE, - params, - related_request_id: related_request_id, - timeout: timeout, - ) - end - - # Sends an embedded SEP-2322 `inputRequests` entry as a real server-to-client request on the legacy wire, - # for the server's dual-era fulfilment shim. - # The entry is forwarded verbatim - per the spec, clients treat each entry exactly like the equivalent - # standalone request - and stays associated with the originating client request per SEP-2260. - # Returns the client's result. - def fulfill_input_request(method, params, related_request_id:) - send_to_transport_request(method, params, related_request_id: related_request_id) - end - - # Sends `notifications/cancelled` to the peer for a nested server-to-client request - # that was started inside a now-cancelled parent request. `related_request_id` - # is the parent request id so the notification is routed to the same stream - # (e.g. the parent's POST response stream on `StreamableHTTPTransport`) rather than - # the GET SSE stream. - def send_peer_cancellation(nested_request_id:, related_request_id: nil, reason: nil) - params = { requestId: nested_request_id } - params[:reason] = reason if reason - send_to_transport(Methods::NOTIFICATIONS_CANCELLED, params, related_request_id: related_request_id) - - if @transport.respond_to?(:cancel_pending_request) - @transport.cancel_pending_request(nested_request_id, reason: reason) - end - rescue => e - MCP.configuration.exception_reporter.call(e, { notification: "cancelled", request_id: nested_request_id }) - end - - # Sends an elicitation complete notification scoped to this session. - def notify_elicitation_complete(elicitation_id:) - send_to_transport(Methods::NOTIFICATIONS_ELICITATION_COMPLETE, { elicitationId: elicitation_id }) - rescue => e - @server.report_exception(e, notification: "elicitation_complete") - end - - # Sends a resource updated notification to this session only. - def notify_resources_updated(uri:) - send_to_transport(Methods::NOTIFICATIONS_RESOURCES_UPDATED, { "uri" => uri }) - rescue => e - @server.report_exception(e, notification: "resources_updated") - end - - # Sends a progress notification to this session only. - def notify_progress(progress_token:, progress:, total: nil, message: nil, related_request_id: nil) - params = { - "progressToken" => progress_token, - "progress" => progress, - "total" => total, - "message" => message, - }.compact - - send_to_transport(Methods::NOTIFICATIONS_PROGRESS, params, related_request_id: related_request_id) - rescue => e - @server.report_exception(e, notification: "progress") - end - - # Sends a log message notification to this session only. - # @deprecated MCP Logging (`logging/setLevel` and `notifications/message`) - # is deprecated as of MCP protocol version 2026-07-28 (SEP-2577). - # Use stderr or OpenTelemetry instead. - def notify_log_message(data:, level:, logger: nil, related_request_id: nil) - # In the modern lifecycle, log delivery is authorized per request through the `_meta` envelope's `logLevel` member - # (applied via `configure_logging`); without it no `notifications/message` is sent, and the server-wide level - # does not apply (SEP-2575). - effective_logging = if @era == :modern - @logging_message_notification - else - @logging_message_notification || @server.logging_message_notification - end - - return unless effective_logging&.should_notify?(level) - - params = { "data" => data, "level" => level } - params["logger"] = logger if logger - - send_to_transport(Methods::NOTIFICATIONS_MESSAGE, params, related_request_id: related_request_id) - rescue => e - @server.report_exception(e, { notification: "log_message" }) - end - - private - - def validate_era!(era) - raise ArgumentError, "era must be one of #{ERAS.inspect}" unless ERAS.include?(era) - end - - # Forwards `send_notification` to the transport with only the kwargs the transport's method signature - # actually accepts. Custom transports that implement the abstract `send_notification(method, params = nil)` - # contract continue to work unchanged; bundled transports that declare `session_id:` / `related_request_id:` - # receive the session-scoped routing information. - def send_to_transport(method, params, related_request_id: nil) - kwargs = { - session_id: @session_id, - related_request_id: related_request_id, - }.compact - - forward_to_transport(@transport.method(:send_notification), method, params, kwargs) - end - - # Forwards `send_request` to the transport with only the kwargs the transport's method signature - # actually accepts. Custom transports that implement the abstract `send_request(method, params = nil)` - # contract continue to work; bundled transports that declare `session_id:` / `related_request_id:` / - # `parent_cancellation:` / `server_session:` receive the nested-cancellation plumbing. - # When `related_request_id` names an in-flight request, its `Cancellation` token is looked up - # so that cancelling the parent also cancels this nested server-to-client request. - def send_to_transport_request(method, params, related_request_id: nil, timeout: nil) - parent_cancellation = related_request_id ? lookup_in_flight(related_request_id) : nil - - kwargs = { - session_id: @session_id, - related_request_id: related_request_id, - parent_cancellation: parent_cancellation, - server_session: self, - timeout: timeout, - }.compact - - forward_to_transport(@transport.method(:send_request), method, params, kwargs) - end - - # Calls `transport_method(method, params, **supported)` where `supported` contains only the keys - # the transport's method signature accepts. This keeps bundled transports (which declare the new kwargs) - # working while preserving compatibility with custom transports that implement only the abstract - # `(method, params = nil)` contract. - def forward_to_transport(transport_method, method, params, kwargs) - parameters = transport_method.parameters - accepts_keyrest = parameters.any? { |type, _| type == :keyrest } - supported = if accepts_keyrest - kwargs - else - allowed = parameters.filter_map { |type, name| name if type == :key || type == :keyreq } - kwargs.slice(*allowed) - end - - # Always splat `**supported` even when empty: on Ruby 2.7 the bare `transport_method.call(method, params)` - # form would let the trailing `params` Hash be auto-promoted to keyword arguments when the receiver - # accepts `**kwargs`, breaking handlers that rely on `params` arriving as a positional Hash. - # The explicit splat suppresses that conversion and is a no-op when `supported` is empty. - transport_method.call(method, params, **supported) - end - - # Per SEP-2260, servers MUST send `roots/list`, `sampling/createMessage`, and `elicitation/create` only - # in association with an originating client request (`ping` is exempt). A request without `related_request_id:` is - # delivered on the standalone GET stream by the Streamable HTTP transport, which the 2026-07-28 spec forbids; - # warn so callers migrate to the `server_context` helpers before this becomes an error. - # https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2260 - def warn_unassociated_request(method_name, related_request_id) - return if related_request_id - - warn( - "Calling `ServerSession##{method_name}` without `related_request_id:` is deprecated (SEP-2260): " \ - "server-to-client #{method_name} requests must be associated with an originating client request. " \ - "Use `server_context.#{method_name}` inside a handler, or pass `related_request_id:` explicitly.", - uplevel: 2, - ) - end - end -end diff --git a/lib/mcp/tool.rb b/lib/mcp/tool.rb index 1b76b80..6c86ce5 100644 --- a/lib/mcp/tool.rb +++ b/lib/mcp/tool.rb @@ -1,10 +1,5 @@ # frozen_string_literal: true -require_relative "tool/annotations" -require_relative "tool/input_schema" -require_relative "tool/output_schema" -require_relative "tool/response" - module MCP class Tool class << self @@ -149,7 +144,7 @@ module MCP raise ArgumentError, "Tool names should be between 1 and 128 characters in length (inclusive)." end - unless tool_name.match?(/\A[A-Za-z\d_\-.]+\z/) + unless tool_name.match?(/\A[A-Za-z\d_\-\.]+\z/) raise ArgumentError, <<~MESSAGE Tool names only allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits (0-9), underscore (_), hyphen (-), and dot (.). MESSAGE diff --git a/lib/mcp/tool/input_schema.rb b/lib/mcp/tool/input_schema.rb index 1fca775..724f9bb 100644 --- a/lib/mcp/tool/input_schema.rb +++ b/lib/mcp/tool/input_schema.rb @@ -12,9 +12,9 @@ module MCP end def missing_required_arguments(arguments) - return [] unless @schema[:required].is_a?(Array) + return [] unless schema[:required].is_a?(Array) - (@schema[:required] - arguments.keys.map(&:to_s)) + (schema[:required] - arguments.keys.map(&:to_s)) end def validate_arguments(arguments) diff --git a/lib/mcp/tool/output_schema.rb b/lib/mcp/tool/output_schema.rb index 1d6e2a5..8bf7ed9 100644 --- a/lib/mcp/tool/output_schema.rb +++ b/lib/mcp/tool/output_schema.rb @@ -7,29 +7,12 @@ module MCP class OutputSchema < Schema class ValidationError < StandardError; end - # Root-level keywords whose presence means the user already chose a root schema shape, - # so no `type: "object"` default should be merged in. - ROOT_SCHEMA_KEYWORDS = [:type, :"$ref", :oneOf, :anyOf, :allOf, :not, :if, :const, :enum].freeze - def validate_result(result) errors = fully_validate(result) if errors.any? raise ValidationError, "Invalid result: #{errors.join(", ")}" end end - - private - - # Per SEP-2106, an output schema may be ANY valid JSON Schema 2020-12 document: object, array, primitive, - # or a root-level composition. - # Default the root to an object only when no root schema keyword is present, which preserves the wire output - # of the common `properties`-only shape while leaving e.g. `{ type: "array" }` or `{ oneOf: [...] }` untouched - # (the old unconditional default merged `type: "object"` into root combinators, producing a wrong schema). - def apply_default_root_type! - return if ROOT_SCHEMA_KEYWORDS.any? { |keyword| @schema.key?(keyword) } - - super - end end end end diff --git a/lib/mcp/tool/response.rb b/lib/mcp/tool/response.rb index 9e4b2ec..0d9dccb 100644 --- a/lib/mcp/tool/response.rb +++ b/lib/mcp/tool/response.rb @@ -5,24 +5,17 @@ module MCP class Response NOT_GIVEN = Object.new.freeze - attr_reader :content, :structured_content, :meta + attr_reader :content, :structured_content - def initialize(content = NOT_GIVEN, deprecated_error = NOT_GIVEN, error: false, structured_content: nil, meta: nil) + def initialize(content = nil, deprecated_error = NOT_GIVEN, error: false, structured_content: nil) if deprecated_error != NOT_GIVEN warn("Passing `error` with the 2nd argument of `Response.new` is deprecated. Use keyword argument like `Response.new(content, error: error)` instead.", uplevel: 1) error = deprecated_error end - content_given = !content.equal?(NOT_GIVEN) - @content_provided = content_given && !content.nil? - @content = content_given ? (content || []) : [] + @content = content || [] @error = error @structured_content = structured_content - @meta = meta - end - - def content_provided? - @content_provided end def error? @@ -30,7 +23,7 @@ module MCP end def to_h - { content: content, isError: error?, structuredContent: @structured_content, _meta: meta }.compact + { content: content, isError: error?, structuredContent: @structured_content }.compact end end end diff --git a/lib/mcp/tool/schema.rb b/lib/mcp/tool/schema.rb index 6811d20..f35d18e 100644 --- a/lib/mcp/tool/schema.rb +++ b/lib/mcp/tool/schema.rb @@ -1,183 +1,64 @@ # frozen_string_literal: true -require "digest" -require "json_schemer" +require "json-schema" module MCP class Tool class Schema - # Metaschema validation depends only on schema content, so a given schema - # never needs to be validated more than once. Caching the result lets repeated - # (e.g. dynamically rebuilt) schemas skip the costly traversal. - class ValidationCache - DEFAULT_MAX_SIZE = 1000 - - def initialize(max_size: DEFAULT_MAX_SIZE) - @max_size = max_size - @entries = {} - @mutex = Mutex.new - end - - def validated?(key) - @mutex.synchronize { @entries.key?(key) } - end - - def store(key) - @mutex.synchronize do - @entries.delete(key) - @entries[key] = true - @entries.shift while @entries.size > @max_size - end - end - - def clear - @mutex.synchronize { @entries.clear } - end - end - VALIDATION_CACHE = ValidationCache.new - - # JSON Schema 2020-12 is the default dialect for MCP schema definitions per MCP 2025-11-25 (SEP-1613), - # and SEP-2106 requires tool schemas to conform to the full 2020-12 vocabulary. Both emission and - # runtime validation use this dialect. Because MCP mandates 2020-12, the SDK validates against it - # regardless of any `$schema` a document embeds; for compliant schemas this is the same dialect - # the Python SDK's `jsonschema.validate` resolves to. - JSON_SCHEMA_2020_12_URI = "https://json-schema.org/draft/2020-12/schema" - - # Resource bounds for schema compilation, mirroring the TypeScript SDK's schema bounds (SEP-2106): - # schemas may use the full JSON Schema 2020-12 vocabulary including composition keywords and `$ref`, - # so adversarial documents must be rejected before they can cause excessive validation cost. - # Only same-document references (starting with `#`) are accepted, so schema handling can never trigger network - # or file access. - MAX_SCHEMA_DEPTH = 64 - MAX_SUBSCHEMA_COUNT = 10_000 - - # Reference keywords whose targets the SDK refuses to dereference. Both `$ref` and `$dynamicRef` may carry - # an absolute URI under JSON Schema 2020-12, so a non-same-document value is an external reference. - REFERENCE_KEYWORDS = [:"$ref", :"$dynamicRef"].freeze + attr_reader :schema def initialize(schema = {}) - @schema = JSON.parse(JSON.dump(schema), symbolize_names: true) - apply_default_root_type! - validate_schema_bounds! + @schema = deep_transform_keys(JSON.parse(JSON.dump(schema)), &:to_sym) + @schema[:type] ||= "object" validate_schema! end def ==(other) - other.is_a?(self.class) && @schema == other.instance_variable_get(:@schema) + other.is_a?(self.class) && schema == other.schema end def to_h - return @schema if @schema.key?(:"$schema") - - { "$schema": JSON_SCHEMA_2020_12_URI }.merge(@schema) + @schema end private - # Root-type defaulting hook. The base class preserves the historical behavior of defaulting the root - # to an object schema; `OutputSchema` overrides this because SEP-2106 allows any root schema there. - def apply_default_root_type! - @schema[:type] ||= "object" - end - - # Enforces `MAX_SCHEMA_DEPTH` / `MAX_SUBSCHEMA_COUNT` and the same-document reference rule over - # the whole schema document. - def validate_schema_bounds! - subschema_count = 0 - stack = [[@schema, 1]] - - until stack.empty? - node, depth = stack.pop - if depth > MAX_SCHEMA_DEPTH - raise ArgumentError, - "Invalid JSON Schema: nesting exceeds the maximum depth of #{MAX_SCHEMA_DEPTH}." - end - - case node - when Hash - subschema_count += 1 - if subschema_count > MAX_SUBSCHEMA_COUNT - raise ArgumentError, - "Invalid JSON Schema: document exceeds the maximum of #{MAX_SUBSCHEMA_COUNT} subschema objects." - end - - REFERENCE_KEYWORDS.each do |keyword| - ref = node[keyword] - next unless ref.is_a?(String) && !ref.start_with?("#") - - raise ArgumentError, - "Invalid JSON Schema: only same-document #{keyword} (starting with '#') is supported, got #{ref.inspect}." - end - - node.each_value { |child| stack << [child, depth + 1] } - when Array - node.each { |child| stack << [child, depth + 1] } - end - end - end - - def stringify(obj) - case obj - when Hash - obj.each_with_object({}) { |(k, v), h| h[k.to_s] = stringify(v) } - when Array - obj.map { |v| stringify(v) } - when Symbol - obj.to_s - else - obj - end - end - - # Lazily built so a cache hit in `validate_schema!` avoids the schemer construction cost. - # Memoized per Schema instance because schema content is fixed at construction, - # so the compiled schemer is reusable across many `fully_validate` calls. - # - # Validated against the JSON Schema 2020-12 metaschema per SEP-2106, so `$defs`/`$ref` and - # the rest of the 2020-12 vocabulary resolve natively. - # - # `format: false` preserves the legacy behavior of the previous `json-schema` based implementation, - # which did not enforce `format` keywords. `RegexpError` from a malformed `pattern` is re-raised as - # `ArgumentError` so callers see the same exception class they used to. - def schemer - @schemer ||= JSONSchemer.schema( - stringify(schema_for_validation), - meta_schema: JSON_SCHEMA_2020_12_URI, - format: false, - ) - rescue RegexpError => e - raise ArgumentError, "Invalid JSON Schema: #{e.message}" - end - def fully_validate(data) - schemer.validate(stringify(data)).map { |validation_error| validation_error.fetch("error") } + JSON::Validator.fully_validate(to_h, data) + end + + def deep_transform_keys(schema, &block) + case schema + when Hash + schema.each_with_object({}) do |(key, value), result| + if key.casecmp?("$ref") + raise ArgumentError, "Invalid JSON Schema: $ref is not allowed in tool schemas" + end + + result[yield(key)] = deep_transform_keys(value, &block) + end + when Array + schema.map { |e| deep_transform_keys(e, &block) } + else + schema + end end def validate_schema! - target = schema_for_validation - - # `max_nesting: false` because normalization uses `JSON.dump` (no nesting limit), - # so the default `JSON.generate` limit would raise on a deeply nested schema that - # the initializer already accepted. - key = Digest::SHA256.hexdigest(JSON.generate(target, max_nesting: false)) - return if VALIDATION_CACHE.validated?(key) - - errors = schemer.validate_schema.map { |validation_error| validation_error.fetch("error") } + schema = to_h + gem_path = File.realpath(Gem.loaded_specs["json-schema"].full_gem_path) + schema_reader = JSON::Schema::Reader.new( + accept_uri: false, + accept_file: ->(path) { File.realpath(path.to_s).start_with?(gem_path) }, + ) + metaschema_path = Pathname.new(JSON::Validator.validator_for_name("draft4").metaschema) + # Converts metaschema to a file URI for cross-platform compatibility + metaschema_uri = JSON::Util::URI.file_uri(metaschema_path.expand_path.cleanpath.to_s.tr("\\", "/")) + metaschema = metaschema_uri.to_s + errors = JSON::Validator.fully_validate(metaschema, schema, schema_reader: schema_reader) if errors.any? raise ArgumentError, "Invalid JSON Schema: #{errors.join(", ")}" end - - VALIDATION_CACHE.store(key) - end - - # Strip the top-level `$schema` before validation so the SDK always validates against - # the 2020-12 metaschema (SEP-2106) regardless of any dialect URI a caller embedded in the document. - def schema_for_validation - return @schema unless @schema.key?(:"$schema") - - copy = @schema.dup - copy.delete(:"$schema") - copy end end end diff --git a/lib/mcp/trace_context.rb b/lib/mcp/trace_context.rb deleted file mode 100644 index 0d69ec5..0000000 --- a/lib/mcp/trace_context.rb +++ /dev/null @@ -1,23 +0,0 @@ -# frozen_string_literal: true - -module MCP - # Reserved `_meta` keys for W3C Trace Context propagation, per SEP-414. - # - # The MCP spec reserves the un-prefixed `_meta` keys `traceparent`, `tracestate`, and `baggage` - # (an explicit exception to the reverse-DNS prefix rule for `_meta` keys) so that clients and - # servers can propagate distributed-tracing context across MCP requests. - # The SDK guarantees these keys pass through incoming request `_meta` untouched; tool, prompt, - # and resource handlers can read them from `server_context[:_meta]` and bridge them to a tracing - # system such as the `opentelemetry-ruby` gems. The SDK itself does not depend on OpenTelemetry. - # - # - https://github.com/modelcontextprotocol/modelcontextprotocol/pull/414 - # - https://www.w3.org/TR/trace-context/ - # - https://www.w3.org/TR/baggage/ - module TraceContext - TRACEPARENT_META_KEY = "traceparent" - TRACESTATE_META_KEY = "tracestate" - BAGGAGE_META_KEY = "baggage" - - META_KEYS = [TRACEPARENT_META_KEY, TRACESTATE_META_KEY, BAGGAGE_META_KEY].freeze - end -end diff --git a/lib/mcp/transport.rb b/lib/mcp/transport.rb index c48e3c9..a995c3a 100644 --- a/lib/mcp/transport.rb +++ b/lib/mcp/transport.rb @@ -1,13 +1,10 @@ # frozen_string_literal: true -require "securerandom" - module MCP class Transport # Initialize the transport with the server instance def initialize(server) @server = server - server.transport = self end # Send a response to the client @@ -39,28 +36,10 @@ module MCP send_response(response) if response end - # Send a notification to the client. - # Returns true if the notification was sent successfully. + # Send a notification to the client + # Returns true if the notification was sent successfully def send_notification(method, params = nil) raise NotImplementedError, "Subclasses must implement send_notification" end - - # Send a JSON-RPC request to the client and wait for a response. - def send_request(method, params = nil) - raise NotImplementedError, "Subclasses must implement send_request" - end - - # Whether the transport serves the `subscriptions/listen` notification stream (MCP 2026-07-28, SEP-2575). - # `Server#discover` strips the `listChanged`/`subscribe` capability flags when the transport cannot deliver - # those notifications in the modern lifecycle. - def serves_subscriptions_listen? - false - end - - private - - def generate_request_id - SecureRandom.uuid - end end end diff --git a/lib/mcp/transports/stdio.rb b/lib/mcp/transports/stdio.rb new file mode 100644 index 0000000..3050f26 --- /dev/null +++ b/lib/mcp/transports/stdio.rb @@ -0,0 +1,15 @@ +# frozen_string_literal: true + +require_relative "../server/transports/stdio_transport" + +warn <<~MESSAGE, uplevel: 3 + Use `require "mcp/server/transports/stdio_transport"` instead of `require "mcp/transports/stdio"`. + Also use `MCP::Server::Transports::StdioTransport` instead of `MCP::Transports::StdioTransport`. + This API is deprecated and will be removed in a future release. +MESSAGE + +module MCP + module Transports + StdioTransport = Server::Transports::StdioTransport + end +end diff --git a/lib/mcp/version.rb b/lib/mcp/version.rb index 2d0dff8..4769836 100644 --- a/lib/mcp/version.rb +++ b/lib/mcp/version.rb @@ -1,5 +1,5 @@ # frozen_string_literal: true module MCP - VERSION = "1.5.1" + VERSION = "0.6.0" end diff --git a/mcp.gemspec b/mcp.gemspec index 9c4d602..b1f7667 100644 --- a/mcp.gemspec +++ b/mcp.gemspec @@ -10,7 +10,7 @@ Gem::Specification.new do |spec| spec.summary = "The official Ruby SDK for Model Context Protocol servers and clients" spec.description = spec.summary - spec.homepage = "https://ruby.sdk.modelcontextprotocol.io" + spec.homepage = "https://github.com/modelcontextprotocol/ruby-sdk" spec.license = "Apache-2.0" # Since this library is used by a broad range of users, it does not align its support policy with Ruby's EOL. @@ -19,16 +19,17 @@ Gem::Specification.new do |spec| spec.metadata["allowed_push_host"] = "https://rubygems.org" spec.metadata["changelog_uri"] = "https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v#{spec.version}" spec.metadata["homepage_uri"] = spec.homepage - spec.metadata["source_code_uri"] = "https://github.com/modelcontextprotocol/ruby-sdk" - spec.metadata["bug_tracker_uri"] = "#{spec.metadata["source_code_uri"]}/issues" + spec.metadata["source_code_uri"] = spec.homepage + spec.metadata["bug_tracker_uri"] = "#{spec.homepage}/issues" spec.metadata["documentation_uri"] = "https://rubydoc.info/gems/mcp" - spec.files = Dir["lib/**/*"] - spec.extra_rdoc_files = ["LICENSE", "README.md"] + spec.files = Dir.chdir(File.expand_path("..", __FILE__)) do + %x(git ls-files -z).split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) } + end spec.bindir = "exe" spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) } spec.require_paths = ["lib"] - spec.add_dependency("json_schemer", ">= 2.4") + spec.add_dependency("json-schema", ">= 4.1") end diff --git a/test/initialize_params_test_helper.rb b/test/initialize_params_test_helper.rb deleted file mode 100644 index ccee933..0000000 --- a/test/initialize_params_test_helper.rb +++ /dev/null @@ -1,15 +0,0 @@ -# frozen_string_literal: true - -module InitializeParamsTestHelper - # `initialize` params satisfying the fields required by the MCP schema - # (protocolVersion, capabilities, and clientInfo). Offers the latest handshake version - # so helper-built sessions run the version they request; the counter-offer for - # modern versions has its own dedicated tests. - def initialize_params(**overrides) - { - protocolVersion: MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, - capabilities: {}, - clientInfo: { name: "test-client", version: "1.0.0" }, - }.merge(overrides) - end -end diff --git a/test/json_rpc_handler_test.rb b/test/json_rpc_handler_test.rb index 07db0ec..751d140 100644 --- a/test/json_rpc_handler_test.rb +++ b/test/json_rpc_handler_test.rb @@ -43,18 +43,6 @@ describe JsonRpcHandler do message: "Invalid Request", data: "JSON-RPC version must be 2.0", } - assert_equal 1, @response[:id] - end - - it "returns an error preserving the request id when jsonrpc is missing" do - handle id: 4, method: "add", params: { a: 1, b: 2 } - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "JSON-RPC version must be 2.0", - } - assert_equal 4, @response[:id] end # method @@ -70,7 +58,6 @@ describe JsonRpcHandler do message: "Invalid Request", data: 'Method name must be a string and not start with "rpc."', } - assert_equal 1, @response[:id] end it "returns an error when method begins with 'rpc.'" do @@ -81,7 +68,6 @@ describe JsonRpcHandler do message: "Invalid Request", data: 'Method name must be a string and not start with "rpc."', } - assert_equal 1, @response[:id] end # params @@ -310,6 +296,7 @@ describe JsonRpcHandler do assert_rpc_error expected_error: { code: -32603, message: "Internal error", + data: "Something bad happened", } assert_equal 1, @response[:id] assert_nil @response[:result] @@ -328,50 +315,6 @@ describe JsonRpcHandler do assert_nil @response[:id] end - it "returns the same request id on an Invalid Request error when the id is detectable" do - handle jsonrpc: "1.0", id: 3, method: "ping", params: {} - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "JSON-RPC version must be 2.0", - } - assert_equal 3, @response[:id] - end - - it "returns nil for id on an Invalid Request error when the request has no id" do - handle jsonrpc: "1.0", method: "ping", params: {} - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "JSON-RPC version must be 2.0", - } - assert_nil @response[:id] - end - - it "returns nil for id on an Invalid Request error when the request id is explicitly null" do - handle jsonrpc: "1.0", id: nil, method: "ping", params: {} - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "JSON-RPC version must be 2.0", - } - assert_nil @response[:id] - end - - it "returns nil for id on an Invalid Request error when the id fails validation" do - handle jsonrpc: "1.0", id: "", method: "ping", params: {} - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "JSON-RPC version must be 2.0", - } - assert_nil @response[:id] - end - # 5.1 Error object # # When a rpc call encounters an error, the Response Object MUST contain the error member with a value that is a @@ -451,133 +394,7 @@ describe JsonRpcHandler do assert_rpc_error expected_error: { code: -32603, message: "Internal error", - } - end - - it "returns an error with the code set to -32600 when error_type of RequestHandlerError is :invalid_request" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Invalid request data", - {}, - error_type: :invalid_request, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32600, - message: "Invalid Request", - data: "Invalid request data", - } - end - - it "returns an error with the code set to -32602 when error_type of RequestHandlerError is :invalid_params" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Parameter validation failed", - {}, - error_type: :invalid_params, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32602, - message: "Invalid params", - data: "Parameter validation failed", - } - end - - it "returns an error with the code set to -32700 when error_type of RequestHandlerError is :parse_error" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Failed to parse input", - {}, - error_type: :parse_error, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32700, - message: "Parse error", - data: "Failed to parse input", - } - end - - it "returns an error with the code set to -32603 when error_type of RequestHandlerError is :internal_error" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Internal processing error", - {}, - error_type: :internal_error, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32603, - message: "Internal error", - data: "Internal processing error", - } - end - - it "returns an error with the code set to -32603 when error_type of RequestHandlerError is unknown" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Unknown error occurred", - {}, - error_type: :unknown, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32603, - message: "Internal error", - data: "Unknown error occurred", - } - end - - it "returns a custom error code when RequestHandlerError has error_code set" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Custom error", - nil, - error_code: -32042, - error_data: { elicitations: [{ id: "abc" }] }, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32042, - message: "Custom error", - data: { elicitations: [{ id: "abc" }] }, - } - end - - it "falls back to error_type when error_code is nil" do - register("test_method") do - raise MCP::Server::RequestHandlerError.new( - "Invalid params error", - nil, - error_type: :invalid_params, - ) - end - - handle jsonrpc: "2.0", id: 1, method: "test_method" - - assert_rpc_error expected_error: { - code: -32602, - message: "Invalid params", - data: "Invalid params error", + data: "Something bad happened", } end @@ -666,51 +483,6 @@ describe JsonRpcHandler do assert_nil @response end - - it "preserves the request id of an invalid entry within a batch" do - register("add") { |params| params[:a] + params[:b] } - - handle [ - { jsonrpc: "2.0", id: 100, method: "add", params: { a: 1, b: 2 } }, - { jsonrpc: "1.0", id: 200, method: "add", params: { a: 3, b: 4 } }, - ] - - assert @response.is_a?(Array) - assert_equal [100, 200], @response.map { |result| result[:id] } - assert_equal 3, @response.first[:result] - assert_equal(-32600, @response.last.dig(:error, :code)) - end - - it "returns an invalid request error for a non-object batch element instead of raising" do - [[], [1], ["x"], [nil], [true]].each do |batch| - handle batch - - assert_equal(-32600, @response.dig(:error, :code)) - assert_equal "Invalid Request", @response.dig(:error, :message) - assert_nil @response[:id] - end - end - - it "handles a valid request followed by a non-object element without raising" do - register("add") { |params| params[:a] + params[:b] } - - handle [ - { jsonrpc: "2.0", id: 100, method: "add", params: { a: 1, b: 2 } }, - [], - ] - - assert @response.is_a?(Array) - assert_equal 3, @response.first[:result] - assert_equal(-32600, @response.last.dig(:error, :code)) - assert_nil @response.last[:id] - end - - it "does not raise from handle_json when a batch element is not an object" do - result = handle_json("[[]]") - - assert_equal(-32600, @response.dig(:error, :code)) - refute_nil result - end end # 7 Examples @@ -759,7 +531,7 @@ describe JsonRpcHandler do @response = JsonRpcHandler.handle( { jsonrpc: "2.0", id: "user@example.com", method: "add", params: { a: 1, b: 2 } }, id_validation_pattern: custom_pattern, - ) { |method_name, _request_id| @registry[method_name] } + ) { |method_name| @registry[method_name] } assert_rpc_success expected_result: 3 assert_equal "user@example.com", @response[:id] @@ -771,7 +543,7 @@ describe JsonRpcHandler do @response = JsonRpcHandler.handle( { jsonrpc: "2.0", id: "id", method: "add", params: { a: 1, b: 2 } }, id_validation_pattern: nil, - ) { |method_name, _request_id| @registry[method_name] } + ) { |method_name| @registry[method_name] } assert_rpc_success expected_result: 3 assert_equal "", @response[:id] @@ -857,11 +629,10 @@ describe JsonRpcHandler do assert_nil @response end - it "returns an error preserving the request id when the request is invalid" do + it "returns an error with the id set to nil when the request is invalid" do handle_json({ jsonrpc: "0.0", id: 1, method: "add", params: { a: 1, b: 2 } }.to_json) - assert_equal 1, @response[:id] - assert_equal(-32600, @response.dig(:error, :code)) + assert_nil @response[:id] end end @@ -872,11 +643,11 @@ describe JsonRpcHandler do end def handle(request) - @response = JsonRpcHandler.handle(request) { |method_name, _request_id| @registry[method_name] } + @response = JsonRpcHandler.handle(request) { |method_name| @registry[method_name] } end def handle_json(request_json) - @response_json = JsonRpcHandler.handle_json(request_json) { |method_name, _request_id| @registry[method_name] } + @response_json = JsonRpcHandler.handle_json(request_json) { |method_name| @registry[method_name] } @response = JSON.parse(@response_json, symbolize_names: true) if @response_json end diff --git a/test/mcp/annotations_test.rb b/test/mcp/annotations_test.rb deleted file mode 100644 index 1e5d3df..0000000 --- a/test/mcp/annotations_test.rb +++ /dev/null @@ -1,130 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class AnnotationsTest < ActiveSupport::TestCase - def test_initialization - annotations = Annotations.new(audience: ["user"], priority: 0.8) - - assert_equal(["user"], annotations.audience) - assert_equal(0.8, annotations.priority) - assert_nil(annotations.last_modified) - - assert_equal({ audience: ["user"], priority: 0.8 }, annotations.to_h) - end - - def test_initialization_with_all_attributes - timestamp = Time.utc(2025, 1, 12, 15, 0, 58).iso8601 - annotations = Annotations.new(audience: ["user"], priority: 0.8, last_modified: timestamp) - - assert_equal(["user"], annotations.audience) - assert_equal(0.8, annotations.priority) - assert_equal(timestamp, annotations.last_modified) - - assert_equal({ audience: ["user"], priority: 0.8, lastModified: timestamp }, annotations.to_h) - end - - def test_initialization_by_default - annotations = Annotations.new - - assert_nil(annotations.audience) - assert_nil(annotations.priority) - assert_nil(annotations.last_modified) - - assert_equal({}, annotations.to_h) - end - - def test_initialization_with_partial_attributes - annotations = Annotations.new(audience: ["user"]) - - assert_equal(["user"], annotations.audience) - assert_nil(annotations.priority) - assert_nil(annotations.last_modified) - - assert_equal({ audience: ["user"] }, annotations.to_h) - end - - def test_initialization_with_last_modified_only - timestamp = Time.utc(2025, 1, 12, 15, 0, 58).iso8601 - annotations = Annotations.new(last_modified: timestamp) - - assert_nil(annotations.audience) - assert_nil(annotations.priority) - assert_equal(timestamp, annotations.last_modified) - - assert_equal({ lastModified: timestamp }, annotations.to_h) - end - - def test_valid_priority_at_lower_bound - assert_nothing_raised do - Annotations.new(priority: 0) - end - end - - def test_valid_priority_at_upper_bound - assert_nothing_raised do - Annotations.new(priority: 1) - end - end - - def test_invalid_priority_above_upper_bound - exception = assert_raises(ArgumentError) do - Annotations.new(priority: 1.5) - end - assert_equal("The value of priority must be between 0 and 1.", exception.message) - end - - def test_invalid_priority_below_lower_bound - exception = assert_raises(ArgumentError) do - Annotations.new(priority: -0.1) - end - assert_equal("The value of priority must be between 0 and 1.", exception.message) - end - - def test_valid_audience_with_user - assert_nothing_raised do - Annotations.new(audience: ["user"]) - end - end - - def test_valid_audience_with_assistant - assert_nothing_raised do - Annotations.new(audience: ["assistant"]) - end - end - - def test_valid_audience_with_multiple_roles - assert_nothing_raised do - Annotations.new(audience: ["user", "assistant"]) - end - end - - def test_valid_audience_with_empty_array - assert_nothing_raised do - Annotations.new(audience: []) - end - end - - def test_invalid_audience_with_unknown_role - exception = assert_raises(ArgumentError) do - Annotations.new(audience: ["developers"]) - end - assert_equal('The value of audience must be an array of "user" or "assistant".', exception.message) - end - - def test_invalid_audience_with_mixed_roles - exception = assert_raises(ArgumentError) do - Annotations.new(audience: ["user", "developers"]) - end - assert_equal('The value of audience must be an array of "user" or "assistant".', exception.message) - end - - def test_invalid_audience_when_not_array - exception = assert_raises(ArgumentError) do - Annotations.new(audience: "user") - end - assert_equal('The value of audience must be an array of "user" or "assistant".', exception.message) - end - end -end diff --git a/test/mcp/apps_test.rb b/test/mcp/apps_test.rb deleted file mode 100644 index ad00d2a..0000000 --- a/test/mcp/apps_test.rb +++ /dev/null @@ -1,69 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class AppsTest < ActiveSupport::TestCase - test "exposes the SEP-1865 wire vocabulary" do - # The exact strings are shared with the reference ext-apps package and the Python SDK. - assert_equal "io.modelcontextprotocol/ui", Apps::EXTENSION_ID - assert_equal "text/html;profile=mcp-app", Apps::RESOURCE_MIME_TYPE - assert_equal "ui://", Apps::URI_SCHEME - assert_equal "ui/resourceUri", Apps::RESOURCE_URI_META_KEY - end - - test ".capability builds the extensions fragment" do - assert_equal({ "io.modelcontextprotocol/ui" => { mimeTypes: ["text/html;profile=mcp-app"] } }, Apps.capability) - assert_equal({ "io.modelcontextprotocol/ui" => { mimeTypes: ["text/html"] } }, Apps.capability(mime_types: ["text/html"])) - end - - test ".ui_resource builds a Resource with the spec defaults and validates the scheme" do - resource = Apps.ui_resource(uri: "ui://weather/dashboard", name: "dashboard", description: "Weather UI") - - assert_instance_of Resource, resource - assert_equal "ui://weather/dashboard", resource.uri - assert_equal "text/html;profile=mcp-app", resource.mime_type - assert_equal "Weather UI", resource.description - assert_raises(ArgumentError) do - Apps.ui_resource(uri: "file:///dashboard.html", name: "dashboard") - end - end - - test ".tool_meta links a tool to its template without clobbering caller meta" do - meta = Apps.tool_meta( - resource_uri: "ui://weather/dashboard", - visibility: ["model", "app"], - meta: { custom: "value" }, - ) - - assert_equal({ custom: "value", ui: { resourceUri: "ui://weather/dashboard", visibility: ["model", "app"] } }, meta) - assert_raises(ArgumentError) do - Apps.tool_meta(resource_uri: "https://example.com") - end - end - - test ".tool_meta emits the legacy flat key when requested" do - meta = Apps.tool_meta(resource_uri: "ui://weather/dashboard", legacy: true) - - assert_equal "ui://weather/dashboard", meta.dig(:ui, :resourceUri) - assert_equal "ui://weather/dashboard", meta[:"ui/resourceUri"] - end - - test ".client_supports? checks the declared extension and mime types" do - declared = { extensions: { "io.modelcontextprotocol/ui" => { mimeTypes: ["text/html;profile=mcp-app"] } } } - string_keys = { - "extensions" => { "io.modelcontextprotocol/ui" => { "mimeTypes" => ["text/html;profile=mcp-app"] } }, - } - without_mime_types = { extensions: { "io.modelcontextprotocol/ui" => {} } } - other_mime_type = { extensions: { "io.modelcontextprotocol/ui" => { mimeTypes: ["text/html"] } } } - - assert Apps.client_supports?(declared) - assert Apps.client_supports?(string_keys) - assert Apps.client_supports?(without_mime_types) - refute Apps.client_supports?(other_mime_type) - refute Apps.client_supports?({}) - refute Apps.client_supports?(nil) - refute Apps.client_supports?({ extensions: {} }) - end - end -end diff --git a/test/mcp/cancellation_test.rb b/test/mcp/cancellation_test.rb deleted file mode 100644 index 41449eb..0000000 --- a/test/mcp/cancellation_test.rb +++ /dev/null @@ -1,66 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class CancellationTest < ActiveSupport::TestCase - test "starts not cancelled" do - cancellation = Cancellation.new - - refute_predicate cancellation, :cancelled? - assert_nil cancellation.reason - end - - test "#cancel flips state and stores reason" do - cancellation = Cancellation.new - - assert cancellation.cancel(reason: "user requested") - assert_predicate cancellation, :cancelled? - assert_equal "user requested", cancellation.reason - end - - test "#cancel is idempotent" do - cancellation = Cancellation.new - - assert cancellation.cancel(reason: "first") - refute cancellation.cancel(reason: "second") - assert_equal "first", cancellation.reason - end - - test "#on_cancel fires once on cancellation" do - cancellation = Cancellation.new - fired = [] - - cancellation.on_cancel { |reason| fired << reason } - cancellation.cancel(reason: "stop") - cancellation.cancel(reason: "again") - - assert_equal ["stop"], fired - end - - test "#on_cancel fires immediately when already cancelled" do - cancellation = Cancellation.new - cancellation.cancel(reason: "done") - fired = [] - - cancellation.on_cancel { |reason| fired << reason } - - assert_equal ["done"], fired - end - - test "#raise_if_cancelled! raises CancelledError when cancelled" do - cancellation = Cancellation.new(request_id: "req-1") - cancellation.cancel(reason: "abort") - - error = assert_raises(CancelledError) { cancellation.raise_if_cancelled! } - assert_equal "req-1", error.request_id - assert_equal "abort", error.reason - end - - test "#raise_if_cancelled! is a no-op when not cancelled" do - cancellation = Cancellation.new - - assert_nil cancellation.raise_if_cancelled! - end - end -end diff --git a/test/mcp/client/elicitation_test.rb b/test/mcp/client/elicitation_test.rb deleted file mode 100644 index a6d936f..0000000 --- a/test/mcp/client/elicitation_test.rb +++ /dev/null @@ -1,100 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/elicitation" - -module MCP - class Client - class ElicitationTest < Minitest::Test - REQUESTED_SCHEMA = { - "type" => "object", - "properties" => { - "name" => { "type" => "string", "default" => "John Doe" }, - "age" => { "type" => "integer", "default" => 30 }, - "score" => { "type" => "number", "default" => 95.5 }, - "status" => { "type" => "string", "enum" => ["active", "inactive", "pending"], "default" => "active" }, - "verified" => { "type" => "boolean", "default" => true }, - }, - "required" => [], - }.freeze - - def test_apply_defaults_fills_all_omitted_fields - content = Elicitation.apply_defaults(REQUESTED_SCHEMA) - - assert_equal( - { - "name" => "John Doe", - "age" => 30, - "score" => 95.5, - "status" => "active", - "verified" => true, - }, - content, - ) - end - - def test_apply_defaults_does_not_overwrite_provided_values - content = Elicitation.apply_defaults(REQUESTED_SCHEMA, { "name" => "Alice", "verified" => false }) - - assert_equal( - { - "name" => "Alice", - "verified" => false, - "age" => 30, - "score" => 95.5, - "status" => "active", - }, - content, - ) - end - - def test_apply_defaults_skips_properties_without_a_default - schema = { - "type" => "object", - "properties" => { - "name" => { "type" => "string", "default" => "John Doe" }, - "email" => { "type" => "string" }, - }, - } - - content = Elicitation.apply_defaults(schema) - - assert_equal({ "name" => "John Doe" }, content) - refute(content.key?("email")) - end - - def test_apply_defaults_applies_a_false_default - schema = { - "type" => "object", - "properties" => { - "verified" => { "type" => "boolean", "default" => false }, - }, - } - - content = Elicitation.apply_defaults(schema) - - assert_equal({ "verified" => false }, content) - end - - def test_apply_defaults_supports_symbol_keyed_schemas_and_content - schema = { - type: "object", - properties: { - name: { type: "string", default: "John Doe" }, - age: { type: "integer", default: 30 }, - }, - } - - content = Elicitation.apply_defaults(schema, { age: 42 }) - - assert_equal({ "age" => 42, "name" => "John Doe" }, content) - end - - def test_apply_defaults_returns_content_when_schema_has_no_properties - content = Elicitation.apply_defaults({ "type" => "object" }, { "name" => "Alice" }) - - assert_equal({ "name" => "Alice" }, content) - end - end - end -end diff --git a/test/mcp/client/http_test.rb b/test/mcp/client/http_test.rb index 0b9960a..fffda7f 100644 --- a/test/mcp/client/http_test.rb +++ b/test/mcp/client/http_test.rb @@ -1,7 +1,6 @@ # frozen_string_literal: true require "test_helper" -require "event_stream_parser" require "faraday" require "webmock/minitest" require "mcp/client/http" @@ -11,8 +10,6 @@ require "mcp/client" module MCP class Client class HTTPTest < Minitest::Test - include DeprecationWarningTestHelper - def test_raises_load_error_when_faraday_not_available client = HTTP.new(url: url) @@ -28,26 +25,6 @@ module MCP assert_includes(error.message, "Add it to your Gemfile: gem 'faraday', '>= 2.0'") end - def test_raises_load_error_when_event_stream_parser_not_available - stub_request(:post, url) - .to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "data: {}\n\n", - ) - - HTTP.any_instance.stubs(:require).with("faraday").returns(true) - HTTP.const_get(:SSEStream).any_instance.stubs(:require).with("event_stream_parser") - .raises(LoadError, "cannot load such file -- event_stream_parser") - - error = assert_raises(LoadError) do - client.send_request(request: { method: "tools/list" }) - end - - assert_includes(error.message, "The 'event_stream_parser' gem is required to parse SSE responses") - assert_includes(error.message, "Add it to your Gemfile: gem 'event_stream_parser', '>= 1.0'") - end - def test_headers_are_added_to_the_request headers = { "Authorization" => "Bearer token" } client = HTTP.new(url: url, headers: headers) @@ -125,238 +102,6 @@ module MCP custom_client.send_request(request: request) end - def test_mcp_method_and_name_headers_for_tools_call - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "get_weather", arguments: { city: "Tokyo" } }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "get_weather" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_falls_back_to_uri_for_resources_read - request = { - jsonrpc: "2.0", - id: "test_id", - method: "resources/read", - params: { uri: "file:///README.md" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "resources/read", "Mcp-Name" => "file:///README.md" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_method_and_name_headers_for_prompts_get - request = { - jsonrpc: "2.0", - id: "test_id", - method: "prompts/get", - params: { name: "greeting" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "prompts/get", "Mcp-Name" => "greeting" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_method_header_without_name_when_params_lack_name_and_uri - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/list" }, - ) do |req| - !req.headers.key?("Mcp-Name") - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: [] } }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_is_base64_encoded_when_unsafe - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "café" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "=?base64?Y2Fmw6k=?=" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_method_header_for_notification_without_id - request = { - jsonrpc: "2.0", - method: "notifications/initialized", - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "notifications/initialized" }, - ) do |req| - !req.headers.key?("Mcp-Name") - end.to_return( - status: 202, - headers: { "Content-Type" => "application/json" }, - body: "", - ) - - client.send_request(request: request) - end - - def test_mcp_method_header_for_initialize_without_params - request = { - jsonrpc: "2.0", - id: "test_id", - method: "initialize", - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "initialize" }, - ) do |req| - !req.headers.key?("Mcp-Name") - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_with_string_keyed_params - request = { - "jsonrpc" => "2.0", - "id" => "test_id", - "method" => "tools/call", - "params" => { "name" => "get_weather" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "get_weather" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_is_base64_encoded_when_value_has_surrounding_whitespace - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: " padded " }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "=?base64?IHBhZGRlZCA=?=" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_is_base64_encoded_when_value_has_crlf - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "evil\r\nX-Injected: 1" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "=?base64?ZXZpbA0KWC1JbmplY3RlZDogMQ==?=" }, - ) do |req| - !req.headers.key?("X-Injected") - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_name_header_re_encodes_value_matching_base64_sentinel - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "=?base64?literal?=" }, - } - - stub_request(:post, url).with( - headers: { "Mcp-Method" => "tools/call", "Mcp-Name" => "=?base64?PT9iYXNlNjQ/bGl0ZXJhbD89?=" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - - def test_mcp_method_header_without_name_for_non_hash_params - request = { - jsonrpc: "2.0", - id: "test_id", - method: "custom/method", - params: ["positional"], - } - - stub_request(:post, url).with(headers: { "Mcp-Method" => "custom/method" }) do |req| - !req.headers.key?("Mcp-Name") - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: {} }.to_json, - ) - - client.send_request(request: request) - end - def test_send_request_returns_faraday_response request = { jsonrpc: "2.0", @@ -437,7 +182,7 @@ module MCP assert_equal({ method: "tools/list", params: nil }, error.request) end - def test_send_request_raises_not_found_error_on_404_without_session + def test_send_request_raises_not_found_error request = { jsonrpc: "2.0", id: "test_id", @@ -452,56 +197,11 @@ module MCP client.send_request(request: request) end - refute_kind_of(SessionExpiredError, error) assert_equal("The tools/list request is not found", error.message) assert_equal(:not_found, error.error_type) assert_equal({ method: "tools/list", params: nil }, error.request) end - def test_send_request_raises_session_expired_error_on_404_with_session - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - stub_request(:post, url).to_return(status: 404) - - error = assert_raises(SessionExpiredError) do - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - end - - assert_equal(:not_found, error.error_type) - end - - def test_session_expired_error_is_a_request_handler_error - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - stub_request(:post, url).to_return(status: 404) - - error = assert_raises(RequestHandlerError) do - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - end - - assert_kind_of(SessionExpiredError, error) - end - def test_send_request_raises_unprocessable_entity_error request = { jsonrpc: "2.0", @@ -542,32 +242,7 @@ module MCP assert_equal({ method: "tools/list", params: nil }, error.request) end - def test_block_customizes_faraday_connection - custom_client = HTTP.new(url: url) do |faraday| - faraday.headers["X-Custom"] = "test-value" - end - - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - - stub_request(:post, url).with( - headers: { - "X-Custom" => "test-value", - "Accept" => "application/json, text/event-stream", - }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: [] } }.to_json, - ) - - custom_client.send_request(request: request) - end - - def test_send_request_raises_error_for_unsupported_content_type + def test_send_request_raises_error_for_non_json_response request = { jsonrpc: "2.0", id: "test_id", @@ -578,8 +253,8 @@ module MCP .with(body: request.to_json) .to_return( status: 200, - headers: { "Content-Type" => "text/html" }, - body: "", + headers: { "Content-Type" => "text/event-stream" }, + body: "data: {}\n\n", ) error = assert_raises(RequestHandlerError) do @@ -587,2017 +262,19 @@ module MCP end assert_equal( - 'Unsupported Content-Type: "text/html". Expected application/json or text/event-stream.', + 'Unsupported Content-Type: "text/event-stream". This client only supports JSON responses.', error.message, ) assert_equal(:unsupported_media_type, error.error_type) assert_equal({ method: "tools/list", params: nil }, error.request) end - def test_send_request_parses_sse_response - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - - sse_body = <<~SSE - : comment - data: {"jsonrpc":"2.0","method":"notifications/progress","params":{}} - - data: {"jsonrpc":"2.0","id":"test_id","result":{"tools":[{"name":"echo"}]}} - - SSE - - stub_request(:post, url) - .with(body: request.to_json) - .to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - response = client.send_request(request: request) - - assert_equal({ "tools" => [{ "name" => "echo" }] }, response["result"]) - end - - def test_send_request_parses_sse_error_response - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - - sse_body = <<~SSE - data: {"jsonrpc":"2.0","id":"test_id","error":{"code":-32600,"message":"Invalid request"}} - - SSE - - stub_request(:post, url) - .with(body: request.to_json) - .to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - response = client.send_request(request: request) - - assert_equal(-32600, response.dig("error", "code")) - assert_equal("Invalid request", response.dig("error", "message")) - end - - def test_send_request_returns_nil_for_202_accepted_response - request = { - jsonrpc: "2.0", - method: "notifications/initialized", - } - - stub_request(:post, url) - .with(body: request.to_json) - .to_return(status: 202, body: "") - - response = client.send_request(request: request) - - assert_nil(response) - end - - def test_send_request_raises_error_for_sse_without_response - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - - sse_body = <<~SSE - : just a comment - data: {"jsonrpc":"2.0","method":"notifications/progress","params":{}} - - SSE - - stub_request(:post, url) - .with(body: request.to_json) - .to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - error = assert_raises(RequestHandlerError) do - client.send_request(request: request) - end - - assert_includes(error.message, "No valid JSON-RPC response found in SSE stream") - assert_equal(:parse_error, error.error_type) - assert_not_requested(:get, url) - end - - def test_send_request_reconnects_with_last_event_id_after_primed_graceful_close - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_reconnection", arguments: {} }, - } - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-1\nretry: 100\ndata:\n\n", - ) - - get_body = "id: event-2\nretry: 100\ndata:\n\n" \ - "event: message\nid: event-3\n" \ - 'data: {"jsonrpc":"2.0","id":"test_id","result":{"content":[]}}' \ - "\n\n" - get_stub = stub_request(:get, url).with( - headers: { "Accept" => "text/event-stream", "Last-Event-ID" => "event-1" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: get_body, - ) - - started_at = Process.clock_gettime(Process::CLOCK_MONOTONIC) - response = client.send_request(request: request) - elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - started_at - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(get_stub) - - # The server-specified `retry:` interval must elapse before the reconnection GET. - assert_operator(elapsed, :>=, 0.1) - end - - def test_send_request_uses_default_reconnection_delay_when_retry_field_absent - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_reconnection", arguments: {} }, - } - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-1\ndata:\n\n", - ) - - get_body = 'data: {"jsonrpc":"2.0","id":"test_id","result":{"content":[]}}' \ - "\n\n" - stub_request(:get, url).with( - headers: { "Last-Event-ID" => "event-1" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: get_body, - ) - - client.expects(:sleep).with(HTTP::DEFAULT_RECONNECTION_DELAY_MS / 1000.0) - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - end - - def test_send_request_releases_the_calling_thread_on_an_excessive_reconnection_delay - # A server priming a stream, closing it, and asking for a day-long `retry:` used to park - # the calling thread for that long. The default budget now stops the resume without sleeping. - stub_reconnection_with_retry(86_400_000) - client.expects(:sleep).never - - error = assert_raises(MCP::Client::RequestHandlerError) do - client.send_request(request: reconnection_request) - end - - assert_includes error.message, "reconnection budget" - end - - def test_send_request_raises_a_server_reconnection_delay_of_zero_to_the_minimum - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_reconnection", arguments: {} }, - } - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-1\nretry: 0\ndata:\n\n", - ) - - get_body = 'data: {"jsonrpc":"2.0","id":"test_id","result":{"content":[]}}' \ - "\n\n" - stub_request(:get, url).with( - headers: { "Last-Event-ID" => "event-1" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: get_body, - ) - - client.expects(:sleep).with(HTTP::MIN_RECONNECTION_DELAY_MS / 1000.0) - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - end - - def test_send_request_honors_a_reconnection_delay_that_fits_the_budget - # Nothing is shortened while the server's `retry:` fits: the client waits it out and resumes. - custom_client = HTTP.new(url: url, max_reconnection_wait: 60) - - stub_reconnection_with_retry(30_000) - custom_client.expects(:sleep).with(30.0) - - response = custom_client.send_request(request: reconnection_request) - - assert_equal({ "content" => [] }, response["result"]) - end - - def test_send_request_gives_up_rather_than_reconnect_before_the_server_asked - # A delay past the budget is never shortened; the client stops trying to resume instead, so - # the calling thread is released immediately rather than after the server's chosen interval. - custom_client = HTTP.new(url: url, max_reconnection_wait: 10) - - stub_reconnection_with_retry(86_400_000) - custom_client.expects(:sleep).never - - error = assert_raises(MCP::Client::RequestHandlerError) do - custom_client.send_request(request: reconnection_request) - end - - assert_includes error.message, "would exceed the 10 second reconnection budget" - end - - def test_send_request_falls_back_to_the_default_delay_for_an_unusable_retry_value - # The SSE parser only accepts a run of digits, so a negative or non-numeric `retry:` never reaches - # the delay calculation as a value; both arrive as "the server sent none". - ["-5000", "abc", "1e6", "500ms"].each do |value| - WebMock.reset! - fresh_client = HTTP.new(url: url) - - stub_reconnection_with_retry(value) - fresh_client.expects(:sleep).with(HTTP::DEFAULT_RECONNECTION_DELAY_MS / 1000.0) - - response = fresh_client.send_request(request: reconnection_request) - - assert_equal({ "content" => [] }, response["result"]) - end - end - - def test_listener_applies_the_delay_floor_to_a_zero_retry_value - # The listening stream reconnects indefinitely after a graceful close, so a `retry: 0` would spin - # without the floor. The 500s that follow let the listener reach its failure cap and stop. - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - stub_request(:get, url).to_return( - { status: 200, headers: { "Content-Type" => "text/event-stream" }, body: "id: e1\nretry: 0\ndata:\n\n" }, - { status: 500 }, - { status: 500 }, - ) - - client.expects(:sleep).with(HTTP::MIN_RECONNECTION_DELAY_MS / 1000.0).at_least_once - client.connect - client.on_server_request("elicitation/create") { { action: "decline" } } - listener = client.instance_variable_get(:@listener_thread) - - wait_until { !listener.alive? } - ensure - client.close - end - - def test_raises_argument_error_when_max_reconnection_wait_is_not_positive - [0, -1, "60", nil].each do |value| - error = assert_raises(ArgumentError) { HTTP.new(url: url, max_reconnection_wait: value) } - - assert_equal("max_reconnection_wait must be a positive number", error.message) - end - end - - def test_send_request_raises_after_reconnection_attempts_are_exhausted - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_reconnection", arguments: {} }, - } - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-1\nretry: 10\ndata:\n\n", - ) - - first_get = stub_request(:get, url).with( - headers: { "Last-Event-ID" => "event-1" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-2\nretry: 10\ndata:\n\n", - ) - second_get = stub_request(:get, url).with( - headers: { "Last-Event-ID" => "event-2" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-3\nretry: 10\ndata:\n\n", - ) - - error = assert_raises(RequestHandlerError) do - client.send_request(request: request) - end - - assert_includes(error.message, "after 2 reconnection attempts") - assert_equal(:internal_error, error.error_type) - assert_requested(first_get) - assert_requested(second_get) - end - - def test_send_request_parses_json_response_when_adapter_does_not_stream - # The Faraday test adapter ignores `on_data`, like adapters without - # streaming support; the body must be read from `response.body`. - stubs = Faraday::Adapter::Test::Stubs.new do |stub| - stub.post("/") do - [200, { "Content-Type" => "application/json" }, { result: { tools: [] } }.to_json] - end - end - client = HTTP.new(url: url) { |faraday| faraday.adapter(:test, stubs) } - - response = client.send_request(request: { jsonrpc: "2.0", id: "test_id", method: "tools/list" }) - - assert_equal({ "result" => { "tools" => [] } }, response) - end - - def test_send_request_parses_a_json_body_with_a_parser_taking_keyword_options_only - # json 3.0 accepts parser options as keywords only, and Faraday's json response middleware - # passes them as a positional Hash, which Ruby 3 no longer converts. The stand-in parser has - # the json 3.0 signature, so the body must reach `JSON.parse` through the client's own call. - stubs = Faraday::Adapter::Test::Stubs.new do |stub| - stub.post("/") do - [200, { "Content-Type" => "application/json" }, { result: { tools: [] } }.to_json] - end - end - client = HTTP.new(url: url) { |faraday| faraday.adapter(:test, stubs) } - parse = JSON.method(:parse) - keyword_options_only_parse = ->(source, **options) { parse.call(source, **options) } - - response = JSON.stub(:parse, keyword_options_only_parse) do - client.send_request(request: { jsonrpc: "2.0", id: "test_id", method: "tools/list" }) - end - - assert_equal({ "result" => { "tools" => [] } }, response) - end - - def test_send_request_mirrors_x_mcp_header_params_into_mcp_param_headers - # SEP-2243: on a modern connection, `tools/list` teaches the transport the `x-mcp-header` - # declarations, and the following `tools/call` mirrors the annotated arguments into - # `Mcp-Param-*` headers. - call_headers = nil - client = mcp_param_test_client( - tools: [mcp_param_annotated_tool], - on_call: ->(headers) { call_headers = headers }, - ) - client.connect(mode: :modern) - - client.send_request(request: { jsonrpc: "2.0", id: 1, method: "tools/list" }) - client.send_request(request: { - jsonrpc: "2.0", - id: 2, - method: "tools/call", - params: { - name: "test_custom_headers", - arguments: { region: "us-west1", priority: 42, non_ascii_val: "Hello, 世界", null_val: nil }, - }, - }) - - assert_equal("us-west1", call_headers["Mcp-Param-Region"]) - assert_equal("42", call_headers["Mcp-Param-Priority"]) - assert_equal("=?base64?#{["Hello, 世界"].pack("m0")}?=", call_headers["Mcp-Param-NonAsciiVal"]) - refute(call_headers.key?("Mcp-Param-NullVal"), "a null argument must omit its header") - end - - def test_send_request_mirrors_nothing_for_a_tool_with_an_invalid_x_mcp_header_declaration - # An invalid tool definition (here a case-insensitive duplicate) mirrors nothing rather than - # emitting a partial or malformed header set. - invalid_tool = { - name: "invalid_duplicate", - inputSchema: { - type: "object", - properties: { - one: { type: "string", "x-mcp-header": "Region" }, - two: { type: "string", "x-mcp-header": "REGION" }, - }, - }, - } - call_headers = nil - client = mcp_param_test_client(tools: [invalid_tool], on_call: ->(headers) { call_headers = headers }) - client.connect(mode: :modern) - - client.send_request(request: { jsonrpc: "2.0", id: 1, method: "tools/list" }) - client.send_request(request: { - jsonrpc: "2.0", - id: 2, - method: "tools/call", - params: { name: "invalid_duplicate", arguments: { one: "a", two: "b" } }, - }) - - refute(call_headers.keys.any? { |key| key.start_with?("Mcp-Param-") }) - assert_equal("tools/call", call_headers["Mcp-Method"]) - end - - def test_send_request_mirrors_nothing_on_a_legacy_connection - # The custom headers exist on the modern lifecycle only (SEP-2243), matching - # the TypeScript and Python SDKs: without modern adoption nothing is learned or mirrored. - call_headers = nil - client = mcp_param_test_client( - tools: [mcp_param_annotated_tool], - on_call: ->(headers) { call_headers = headers }, - ) - - client.send_request(request: { jsonrpc: "2.0", id: 1, method: "tools/list" }) - client.send_request(request: { - jsonrpc: "2.0", - id: 2, - method: "tools/call", - params: { name: "test_custom_headers", arguments: { region: "us-west1" } }, - }) - - refute(call_headers.keys.any? { |key| key.start_with?("Mcp-Param-") }) - assert_equal("tools/call", call_headers["Mcp-Method"]) - end - - def test_send_request_prunes_declarations_dropped_by_a_complete_listing - # A complete (uncursored, `nextCursor`-less) listing is the full tool universe, - # so declarations of unlisted tools are stale and stop mirroring. - call_headers = nil - listings = [[mcp_param_annotated_tool], []] - client = mcp_param_test_client( - tools: -> { listings.shift || [] }, - on_call: ->(headers) { call_headers = headers }, - ) - client.connect(mode: :modern) - - client.send_request(request: { jsonrpc: "2.0", id: 1, method: "tools/list" }) - client.send_request(request: { jsonrpc: "2.0", id: 2, method: "tools/list" }) - client.send_request(request: { - jsonrpc: "2.0", - id: 3, - method: "tools/call", - params: { name: "test_custom_headers", arguments: { region: "us-west1" } }, - }) - - refute(call_headers.keys.any? { |key| key.start_with?("Mcp-Param-") }) - end - - def test_send_request_parses_sse_response_when_adapter_does_not_stream - sse_body = "event: message\n" \ - 'data: {"jsonrpc":"2.0","id":"test_id","result":{"tools":[]}}' \ - "\n\n" - stubs = Faraday::Adapter::Test::Stubs.new do |stub| - stub.post("/") do - [200, { "Content-Type" => "text/event-stream" }, sse_body] - end - end - client = HTTP.new(url: url) { |faraday| faraday.adapter(:test, stubs) } - - response = client.send_request(request: { jsonrpc: "2.0", id: "test_id", method: "tools/list" }) - - assert_equal({ "tools" => [] }, response["result"]) - end - - def test_sse_stream_parses_buffered_chunks_when_env_is_unavailable - # Faraday < 2.1 invokes `on_data` without `env`; the content type - # cannot be detected, so SSE chunks accumulate in the buffer and are - # parsed by the `ingest_pending!` fallback. - stream = HTTP.const_get(:SSEStream).new(abortable: true) - chunk = "data: {\"jsonrpc\":\"2.0\",\"id\":\"test_id\",\"result\":{}}\n\n" - - stream.on_data.call(chunk, chunk.bytesize) - - assert_nil(stream.response) - assert_equal(chunk, stream.buffer) - - stream.ingest_pending!(nil) - - assert_equal({ "jsonrpc" => "2.0", "id" => "test_id", "result" => {} }, stream.response) - assert_empty(stream.buffer) - end - - def test_send_request_rejects_sse_event_exceeding_max_message_bytes - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - client = HTTP.new(url: url, max_message_bytes: 64) - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "data: #{"a" * 128}\n", - ) - - error = assert_raises(RequestHandlerError) do - client.send_request(request: request) - end - - assert_includes(error.message, "Server SSE event exceeds 64 bytes") - assert_equal(:internal_error, error.error_type) - end - - def test_send_request_rejects_json_body_exceeding_max_message_bytes - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - client = HTTP.new(url: url, max_message_bytes: 64) - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: ["a" * 128] } }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.send_request(request: request) - end - - assert_includes(error.message, "Server response body exceeds 64 bytes") - assert_equal(:internal_error, error.error_type) - end - - def test_send_request_accepts_sse_events_that_each_stay_within_max_message_bytes - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/list", - } - client = HTTP.new(url: url, max_message_bytes: 256) - - # The notifications and the response together exceed the limit; each event stays - # under it, so dispatched events must not count against the ones that follow. - notification = { jsonrpc: "2.0", method: "notifications/progress", params: { token: "a" * 100 } }.to_json - sse_body = "data: #{notification}\n\n" * 3 + - "data: {\"jsonrpc\":\"2.0\",\"id\":\"test_id\",\"result\":{\"tools\":[]}}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - response = client.send_request(request: request) - - assert_equal({ "tools" => [] }, response["result"]) - end - - def test_sse_stream_rejects_unterminated_event_exceeding_max_message_bytes - stream = HTTP.const_get(:SSEStream).new(abortable: false, max_message_bytes: 64) - env = stub(response_headers: { "content-type" => "text/event-stream" }) - chunk = "data: #{"a" * 128}" - - error = assert_raises(HTTP.const_get(:MessageTooLargeError)) do - stream.on_data.call(chunk, chunk.bytesize, env) - end - - assert_includes(error.message, "Server SSE event exceeds 64 bytes") - end - - def test_sse_stream_bounds_buffered_chunks_when_env_is_unavailable - stream = HTTP.const_get(:SSEStream).new(abortable: true, max_message_bytes: 64) - - error = assert_raises(HTTP.const_get(:MessageTooLargeError)) do - stream.on_data.call("a" * 65, 65) - end - - assert_includes(error.message, "Server response body exceeds 64 bytes") - end - - def test_initialize_rejects_max_message_bytes_that_is_not_a_positive_integer - [0, -1, nil, "4"].each do |value| - error = assert_raises(ArgumentError) do - HTTP.new(url: url, max_message_bytes: value) - end - - assert_equal("max_message_bytes must be a positive Integer", error.message) - end - end - - def test_send_request_dispatches_server_request_to_registered_handler - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_client_elicitation_defaults", arguments: {} }, - } - - elicitation_request = { - jsonrpc: "2.0", - id: 0, - method: "elicitation/create", - params: { - message: "Please accept with defaults", - requestedSchema: { - type: "object", - properties: { name: { type: "string", default: "John Doe" } }, - required: [], - }, - }, - } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = "event: message\ndata: #{elicitation_request.to_json}\n\n" \ - "event: message\ndata: #{tool_result.to_json}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_response = { - jsonrpc: "2.0", - id: 0, - result: { action: "accept", content: { name: "John Doe" } }, - } - response_stub = stub_request(:post, url).with( - body: expected_response.to_json, - ).to_return( - status: 202, body: "", - ) - - received_params = nil - client.on_server_request("elicitation/create") do |params| - received_params = params - { - action: "accept", - content: { name: params.dig("requestedSchema", "properties", "name", "default") }, - } - end - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(response_stub) - assert_equal("Please accept with defaults", received_params["message"]) - end - - def test_send_request_dispatches_sampling_request_to_registered_handler - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "ask_llm", arguments: {} }, - } - - sampling_request = { - jsonrpc: "2.0", - id: 0, - method: "sampling/createMessage", - params: { - messages: [{ role: "user", content: { type: "text", text: "Hi" } }], - maxTokens: 100, - }, - } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = "event: message\ndata: #{sampling_request.to_json}\n\n" \ - "event: message\ndata: #{tool_result.to_json}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_response = { - jsonrpc: "2.0", - id: 0, - result: { - role: "assistant", - content: { type: "text", text: "Hello there" }, - model: "test-model", - stopReason: "endTurn", - }, - } - response_stub = stub_request(:post, url).with( - body: expected_response.to_json, - ).to_return(status: 202, body: "") - - received_params = nil - client.on_server_request("sampling/createMessage") do |params| - received_params = params - { - role: "assistant", - content: { type: "text", text: "Hello there" }, - model: "test-model", - stopReason: "endTurn", - } - end - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(response_stub) - assert_equal(100, received_params["maxTokens"]) - end - - def test_send_request_answers_a_server_ping_with_an_empty_result - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "some_tool", arguments: {} }, - } - - server_ping = { jsonrpc: "2.0", id: 7, method: "ping" } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = <<~BODY - event: message - data: #{server_ping.to_json} - - event: message - data: #{tool_result.to_json} - - BODY - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - pong = { jsonrpc: "2.0", id: 7, result: {} } - pong_stub = stub_request(:post, url).with( - body: pong.to_json, - ).to_return(status: 202, body: "") - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(pong_stub) - end - - def test_a_registered_ping_handler_overrides_the_default_pong - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "some_tool", arguments: {} }, - } - - server_ping = { jsonrpc: "2.0", id: 8, method: "ping" } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = <<~BODY - event: message - data: #{server_ping.to_json} - - event: message - data: #{tool_result.to_json} - - BODY - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_response = { jsonrpc: "2.0", id: 8, result: { custom: "pong" } } - response_stub = stub_request(:post, url).with( - body: expected_response.to_json, - ).to_return(status: 202, body: "") - - client.on_server_request("ping") { { custom: "pong" } } - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(response_stub) - end - - def test_a_ping_with_a_malformed_id_is_answered_with_method_not_found - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "some_tool", arguments: {} }, - } - - # A Hash id is not a JSON-RPC id; the reference SDKs reject such frames at schema - # validation, so the default pong does not fire and the frame falls through. - server_ping = { jsonrpc: "2.0", id: { x: 1 }, method: "ping" } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = <<~BODY - event: message - data: #{server_ping.to_json} - - event: message - data: #{tool_result.to_json} - - BODY - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_error = { - jsonrpc: "2.0", - id: { x: 1 }, - error: { - code: JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, - message: "Method not found: ping", - }, - } - error_stub = stub_request(:post, url).with( - body: expected_error.to_json, - ).to_return(status: 202, body: "") - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(error_stub) - end - - def test_send_request_answers_unregistered_server_request_with_method_not_found - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "some_tool", arguments: {} }, - } - - server_request = { - jsonrpc: "2.0", - id: 5, - method: "sampling/createMessage", - params: {}, - } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = "event: message\ndata: #{server_request.to_json}\n\n" \ - "event: message\ndata: #{tool_result.to_json}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_error_response = { - jsonrpc: "2.0", - id: 5, - error: { code: -32601, message: "Method not found: sampling/createMessage" }, - } - error_stub = stub_request(:post, url).with( - body: expected_error_response.to_json, - ).to_return( - status: 202, body: "", - ) - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(error_stub) - end - - def test_send_request_answers_raising_handler_with_internal_error - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "some_tool", arguments: {} }, - } - - server_request = { - jsonrpc: "2.0", - id: 9, - method: "elicitation/create", - params: {}, - } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = "event: message\ndata: #{server_request.to_json}\n\n" \ - "event: message\ndata: #{tool_result.to_json}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_error_response = { - jsonrpc: "2.0", - id: 9, - error: { code: -32603, message: "Internal error handling elicitation/create request: boom" }, - } - error_stub = stub_request(:post, url).with( - body: expected_error_response.to_json, - ).to_return( - status: 202, body: "", - ) - - client.on_server_request("elicitation/create") { raise "boom" } - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(error_stub) - end - - def test_send_request_answers_server_request_error_with_its_code - request = { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "ask_llm", arguments: {} }, - } - - server_request = { - jsonrpc: "2.0", - id: 11, - method: "sampling/createMessage", - params: {}, - } - tool_result = { jsonrpc: "2.0", id: "test_id", result: { content: [] } } - sse_body = "event: message\ndata: #{server_request.to_json}\n\n" \ - "event: message\ndata: #{tool_result.to_json}\n\n" - - stub_request(:post, url).with( - body: request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: sse_body, - ) - - expected_error_response = { - jsonrpc: "2.0", - id: 11, - error: { code: -1, message: "User rejected sampling request" }, - } - error_stub = stub_request(:post, url).with( - body: expected_error_response.to_json, - ).to_return( - status: 202, body: "", - ) - - client.on_server_request("sampling/createMessage") do - raise MCP::Client::ServerRequestError.new("User rejected sampling request", code: -1) - end - - response = client.send_request(request: request) - - assert_equal({ "content" => [] }, response["result"]) - assert_requested(error_stub) - end - - def test_on_server_request_requires_a_block - assert_raises(ArgumentError) do - client.on_server_request("elicitation/create") - end - end - - def test_registering_a_handler_after_connect_listens_on_standalone_get_stream - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - - elicitation_request = { - jsonrpc: "2.0", - id: 7, - method: "elicitation/create", - params: { - message: "Please accept with defaults", - requestedSchema: { - type: "object", - properties: { name: { type: "string", default: "John Doe" } }, - required: [], - }, - }, - } - stub_request(:get, url) - .with( - headers: { "Accept" => "text/event-stream", "Mcp-Session-Id" => "session-abc" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "event: message\ndata: #{elicitation_request.to_json}\n\n", - ) - - expected_response = { - jsonrpc: "2.0", - id: 7, - result: { action: "accept", content: { name: "John Doe" } }, - } - response_stub = stub_request(:post, url).with( - body: expected_response.to_json, - ).to_return( - status: 202, body: "", - ) - - client.connect - client.on_server_request("elicitation/create") do |params| - { - action: "accept", - content: { name: params.dig("requestedSchema", "properties", "name", "default") }, - } - end - - wait_until { requested?(response_stub) } - - assert_requested(response_stub) - ensure - client.close - end - - def test_connect_listens_on_standalone_get_stream_when_a_handler_is_registered - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - - get_stub = stub_request(:get, url).with( - headers: { "Accept" => "text/event-stream" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "", - ) - - client.on_server_request("elicitation/create") { { action: "decline" } } - - assert_not_requested(:get, url) - - client.connect - - wait_until { requested?(get_stub) } - - assert_requested(get_stub) - ensure - client.close - end - - def test_listener_stops_after_consecutive_connection_failures - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - stub_request(:get, url).to_return(status: 500) - - client.stubs(:sleep) - client.connect - client.on_server_request("elicitation/create") { { action: "decline" } } - listener = client.instance_variable_get(:@listener_thread) - - wait_until { !listener.alive? } - - assert_requested(:get, url, times: HTTP::MAX_RECONNECTION_ATTEMPTS) - ensure - client.close - end - - def test_listener_failure_count_resets_after_a_successful_stream - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - stub_request(:get, url).to_return( - { status: 500 }, - { status: 200, headers: { "Content-Type" => "text/event-stream" }, body: "" }, - { status: 500 }, - { status: 500 }, - ) - - client.stubs(:sleep) - client.connect - client.on_server_request("elicitation/create") { { action: "decline" } } - listener = client.instance_variable_get(:@listener_thread) - - wait_until { !listener.alive? } - - # Without the reset, the second failure (the third request) would - # already reach the cap and the fourth request would never be made. - assert_requested(:get, url, times: 4) - ensure - client.close - end - - def test_listener_stops_immediately_when_server_does_not_offer_a_get_stream - stub_initialize - stub_notification - stub_request(:delete, url).to_return(status: 200) - stub_request(:get, url).to_return(status: 405) - - client.stubs(:sleep) - client.connect - client.on_server_request("elicitation/create") { { action: "decline" } } - listener = client.instance_variable_get(:@listener_thread) - - wait_until { !listener.alive? } - - assert_requested(:get, url, times: 1) - ensure - client.close - end - - def test_captures_session_id_and_protocol_version_on_initialize - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - assert_equal("session-abc", client.session_id) - assert_equal("2025-11-25", client.protocol_version) - end - - def test_includes_session_and_protocol_version_headers_after_initialize - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - stub_request(:post, url) - .with( - headers: { - "Mcp-Session-Id" => "session-abc", - "MCP-Protocol-Version" => "2025-11-25", - }, - ) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: [] } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - end - - def test_adopts_a_counter_offered_protocol_version_from_the_handshake - # A server may answer `initialize` with a version other than the one offered, and everything - # after the handshake speaks the answer rather than the offer. This server counter-offers - # a handshake version to clients asking `initialize` for a modern one, which only resolves - # anything because clients behave this way. - counter_offered = "2025-06-18" - refute_equal( - counter_offered, - MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, - "the counter-offer has to differ from the offer for this to test anything", - ) - - offered = nil - stub_request(:post, url).with do |req| - body = JSON.parse(req.body) - offered = body.dig("params", "protocolVersion") if body["method"] == "initialize" - body["method"] == "initialize" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "session-abc" }, - body: { result: { protocolVersion: counter_offered } }.to_json, - ) - stub_notification - - client.connect - - assert_equal(MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, offered) - assert_equal(counter_offered, client.protocol_version) - - # Scoped to the body as well: `notifications/initialized` already went out under - # the adopted version, and a header-only stub would count that too. - header_stub = stub_request(:post, url).with( - headers: { "MCP-Protocol-Version" => counter_offered }, - ) do |req| - JSON.parse(req.body)["method"] == "tools/list" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: [] } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - - assert_requested(header_stub) - end - - def test_does_not_send_protocol_version_header_before_initialize - stub_request(:post, url) - .with { |req| !req.headers.keys.map(&:downcase).include?("mcp-protocol-version") } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - end - - def test_ignores_empty_session_id_header - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - assert_nil(client.session_id) - end - - def test_session_id_not_overwritten_by_subsequent_responses - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "original-session", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - assert_equal("original-session", client.session_id) - - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "different-session", - }, - body: { result: { tools: [] } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - - assert_equal("original-session", client.session_id) - end - - def test_stateless_server_without_session_id_header - stub_request(:post, url) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - assert_nil(client.session_id) - assert_equal("2025-11-25", client.protocol_version) - end - - def test_clears_session_state_on_404 - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - - assert_equal("session-abc", client.session_id) - - stub_request(:post, url).to_return(status: 404) - - assert_raises(SessionExpiredError) do - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "tools/list" }) - end - - assert_nil(client.session_id) - assert_nil(client.protocol_version) - end - - def test_close_sends_delete_with_session_headers - initialize_session - - stub_request(:delete, url) - .with( - headers: { - "Mcp-Session-Id" => "session-abc", - "MCP-Protocol-Version" => "2025-11-25", - }, - ) - .to_return(status: 200) - - client.close - end - - def test_close_clears_session_state - initialize_session - stub_request(:delete, url).to_return(status: 200) - - client.close - - assert_nil(client.session_id) - assert_nil(client.protocol_version) - end - - def test_close_without_session_is_noop - client.close - - assert_not_requested(:delete, url) - assert_nil(client.session_id) - end - - def test_close_clears_stateless_connection_state - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - stub_notification - - client.connect - client.close - - assert_not_requested(:delete, url) - refute_predicate(client, :connected?) - assert_nil(client.protocol_version) - assert_nil(client.server_info) - end - - def test_close_tolerates_405_response - initialize_session - stub_request(:delete, url).to_return(status: 405) - - client.close - - assert_nil(client.session_id) - end - - def test_close_tolerates_404_response - initialize_session - stub_request(:delete, url).to_return(status: 404) - - client.close - - assert_nil(client.session_id) - end - - def test_close_propagates_server_error_and_still_clears_state - initialize_session - stub_request(:delete, url).to_return(status: 500) - - assert_raises(Faraday::ServerError) do - client.close - end - - assert_nil(client.session_id) - assert_nil(client.protocol_version) - end - - def test_close_propagates_unauthorized_and_still_clears_state - initialize_session - stub_request(:delete, url).to_return(status: 401) - - assert_raises(Faraday::UnauthorizedError) do - client.close - end - - assert_nil(client.session_id) - end - - def test_close_propagates_connection_failure_and_still_clears_state - initialize_session - stub_request(:delete, url).to_raise(Faraday::ConnectionFailed.new("connection refused")) - - assert_raises(Faraday::ConnectionFailed) do - client.close - end - - assert_nil(client.session_id) - end - - def test_close_is_idempotent - initialize_session - stub_request(:delete, url).to_return(status: 200) - - client.close - client.close - - assert_requested(:delete, url, times: 1) - end - - def test_connect_performs_initialize_handshake - init_stub = stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "s1" }, - body: { - result: { - protocolVersion: "2025-11-25", - capabilities: { tools: {} }, - serverInfo: { name: "test-server", version: "1.0" }, - }, - }.to_json, - ) - - notification_stub = stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "notifications/initialized" } - .to_return(status: 202, body: "") - - result = client.connect - - assert_requested(init_stub) - assert_requested(notification_stub) - assert_equal("2025-11-25", result["protocolVersion"]) - assert_equal({ "tools" => {} }, result["capabilities"]) - assert_equal({ "name" => "test-server", "version" => "1.0" }, result["serverInfo"]) - end - - def test_connect_caches_server_info - stub_initialize - stub_notification - - client.connect - - assert_equal("2025-11-25", client.server_info["protocolVersion"]) - end - - def test_connect_uses_default_client_info_and_protocol_version - notification_stub = stub_notification - - init_stub = stub_request(:post, url) - .with do |req| - body = JSON.parse(req.body) - body["method"] == "initialize" && - body["params"]["protocolVersion"] == MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION && - body["params"]["clientInfo"] == { "name" => "mcp-ruby-client", "version" => MCP::VERSION } && - body["params"]["capabilities"] == {} - end - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION } }.to_json, - ) - - client.connect - - assert_requested(init_stub) - assert_requested(notification_stub) - end - - def test_connect_accepts_custom_parameters - notification_stub = stub_notification - - init_stub = stub_request(:post, url) - .with do |req| - body = JSON.parse(req.body) - body["method"] == "initialize" && - body["params"]["protocolVersion"] == "2025-03-26" && - body["params"]["clientInfo"] == { "name" => "my-app", "version" => "9.9" } && - body["params"]["capabilities"] == { "roots" => { "listChanged" => true } } - end - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-03-26" } }.to_json, - ) - - client.connect( - client_info: { name: "my-app", version: "9.9" }, - protocol_version: "2025-03-26", - capabilities: { roots: { listChanged: true } }, - ) - - assert_requested(init_stub) - assert_requested(notification_stub) - end - - def test_connect_offers_the_latest_handshake_version_by_default - # The handshake negotiates legacy versions only (SEP-2575 era model); modern versions are - # selected via `mode: :modern`/`:auto`, so the default offer is the latest handshake version. - offered = nil - init_stub = stub_request(:post, url).with do |req| - body = JSON.parse(req.body) - offered = body.dig("params", "protocolVersion") if body["method"] == "initialize" - body["method"] == "initialize" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - stub_notification - - client.connect - - assert_requested(init_stub) - assert_equal(MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, offered) - end - - def test_connect_rejects_a_modern_protocol_version_in_the_initialize_result - # A server answering `initialize` with a modern version is refused like an unknown one: - # the handshake settles on a legacy version by definition, and the TypeScript and Python clients - # refuse a modern counter-offer the same way. - init_stub = stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2026-07-28" } }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.connect - end - - assert_includes(error.message, "2026-07-28") - assert_requested(init_stub) - end - - def test_connect_raises_argument_error_for_an_explicit_modern_protocol_version_on_the_legacy_handshake - error = assert_raises(ArgumentError) do - client.connect(protocol_version: "2026-07-28", mode: :legacy) - end - - assert_includes(error.message, "cannot be negotiated through the legacy `initialize` handshake") - end - - def test_connect_does_not_warn_for_deprecated_capabilities_when_negotiated_protocol_version_is_older - notification_stub = stub_notification - - init_stub = stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - assert_no_deprecation_warning do - client.connect(capabilities: { roots: { listChanged: true }, sampling: {} }) - end - - assert_requested(init_stub) - assert_requested(notification_stub) - end - - def test_connect_is_idempotent - init_stub = stub_initialize - notification_stub = stub_notification - - first_result = client.connect - second_result = client.connect - - assert_same(first_result, second_result) - assert_requested(init_stub, times: 1) - assert_requested(notification_stub, times: 1) - end - - def test_connect_raises_on_jsonrpc_error_response - stub_request(:post, url).to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "session-abc" }, - body: { error: { code: -32602, message: "Unsupported protocol version" } }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.connect - end - - assert_includes(error.message, "Unsupported protocol version") - refute_predicate(client, :connected?) - assert_nil(client.session_id) - assert_nil(client.protocol_version) - assert_nil(client.server_info) - end - - def test_connect_raises_on_missing_result - stub_request(:post, url).to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "session-abc" }, - body: { jsonrpc: "2.0", id: "x" }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.connect - end - - assert_includes(error.message, "missing result in response") - refute_predicate(client, :connected?) - assert_nil(client.session_id) - assert_nil(client.protocol_version) - assert_nil(client.server_info) - end - - def test_connect_raises_on_unsupported_negotiated_protocol_version - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "session-abc" }, - body: { result: { protocolVersion: "2099-01-01" } }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.connect - end - - assert_includes(error.message, 'unsupported protocol version "2099-01-01"') - refute_predicate(client, :connected?) - assert_nil(client.session_id) - assert_nil(client.protocol_version) - assert_nil(client.server_info) - end - - def test_connect_clears_session_when_initialized_notification_fails - stub_initialize - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "notifications/initialized" } - .to_return(status: 500) - - assert_raises(RequestHandlerError) do - client.connect - end - - refute_predicate(client, :connected?) - assert_nil(client.session_id) - assert_nil(client.protocol_version) - assert_nil(client.server_info) - end - - def test_connected_lifecycle - refute_predicate(client, :connected?) - - stub_initialize - stub_notification - client.connect - - assert_predicate(client, :connected?) - - stub_request(:delete, url).to_return(status: 200) - client.close - - refute_predicate(client, :connected?) - end - - def test_connect_modern_probes_discover_and_adopts_the_modern_lifecycle - discover_stub = stub_discover - - result = client.connect(mode: :modern) - - assert_requested(discover_stub) - assert_predicate(client, :connected?) - assert_predicate(client, :modern?) - assert_equal(["2026-07-28"], result["supportedVersions"]) - assert_equal(result, client.server_info) - assert_equal("2026-07-28", client.protocol_version) - end - - def test_modern_requests_carry_the_envelope_and_matching_header - stub_discover - client.connect( - mode: :modern, - client_info: { name: "my-app", version: "9.9" }, - capabilities: { elicitation: {} }, - ) - - request_stub = stub_request(:post, url).with do |req| - body = JSON.parse(req.body) - meta = body.dig("params", "_meta") - body["method"] == "tools/list" && - req.headers["Mcp-Protocol-Version"] == "2026-07-28" && - meta == { - "io.modelcontextprotocol/protocolVersion" => "2026-07-28", - "io.modelcontextprotocol/clientInfo" => { "name" => "my-app", "version" => "9.9" }, - "io.modelcontextprotocol/clientCapabilities" => { "elicitation" => {} }, - } - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { tools: [] } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_requested(request_stub) - end - - def test_connect_modern_fails_without_a_mutual_modern_version - stub_request(:post, url).with do |req| - JSON.parse(req.body)["method"] == "server/discover" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { supportedVersions: ["2025-11-25"] } }.to_json, - ) - - error = assert_raises(RequestHandlerError) { client.connect(mode: :modern) } - - assert_includes(error.message, "no mutually supported modern protocol version") - refute_predicate(client, :connected?) - refute_predicate(client, :modern?) - end - - def test_connect_auto_falls_back_to_the_legacy_handshake_on_discovery_errors - stub_request(:post, url).with do |req| - JSON.parse(req.body)["method"] == "server/discover" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { error: { code: -32601, message: "Method not found" } }.to_json, - ) - init_stub = stub_initialize - notification_stub = stub_notification - - result = client.connect(mode: :auto) - - assert_requested(init_stub) - assert_requested(notification_stub) - refute_predicate(client, :modern?) - assert_predicate(client, :connected?) - assert_equal("2025-11-25", result["protocolVersion"]) - end - - def test_connect_auto_falls_back_when_discovery_lacks_a_mutual_modern_version - # Rollout tolerance: a server may answer discovery while only serving legacy versions; - # auto mode falls back to the legacy handshake. - stub_request(:post, url).with do |req| - JSON.parse(req.body)["method"] == "server/discover" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { supportedVersions: ["2025-11-25"] } }.to_json, - ) - init_stub = stub_initialize - stub_notification - - client.connect(mode: :auto) - - assert_requested(init_stub) - refute_predicate(client, :modern?) - assert_predicate(client, :connected?) - end - - def test_connect_rejects_unknown_modes_and_legacy_versions_for_modern_mode - assert_raises(ArgumentError) { client.connect(mode: :bogus) } - assert_raises(ArgumentError) { client.connect(mode: :modern, protocol_version: "2025-11-25") } - end - - def test_connect_auto_propagates_the_discovery_failure_for_an_explicitly_modern_version - # An explicitly requested modern version is never downgraded by the fallback: - # the legacy handshake cannot negotiate it, so the probe's failure is the real answer. - stub_request(:post, url).with do |req| - JSON.parse(req.body)["method"] == "server/discover" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { result: { supportedVersions: ["2025-11-25"] } }.to_json, - ) - - error = assert_raises(RequestHandlerError) do - client.connect(mode: :auto, protocol_version: "2026-07-28") - end - - assert_includes(error.message, "no mutually supported modern protocol version") - refute_predicate(client, :connected?) - end - - def test_connect_modern_warns_for_deprecated_capabilities - # SEP-2577 deprecates roots and sampling at 2026-07-28, the revision every - # modern connection speaks. - stub_discover - - assert_deprecation_warning(/MCP Roots .*2026-07-28.*MCP Sampling .*2026-07-28/m) do - client.connect(mode: :modern, capabilities: { roots: { listChanged: true }, sampling: {} }) - end - - assert_predicate(client, :modern?) - end - - def test_reconnect_after_close - stub_initialize - stub_notification - client.connect - stub_request(:delete, url).to_return(status: 200) - client.close - - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "s2" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.connect - - assert_predicate(client, :connected?) - assert_equal("s2", client.session_id) - end - - def test_close_allows_reinitializing_a_fresh_session - initialize_session - stub_request(:delete, url).to_return(status: 200) - client.close - - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-xyz", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "2", method: "initialize" }) - - assert_equal("session-xyz", client.session_id) - assert_equal("2025-11-25", client.protocol_version) - end - - def test_send_notification_posts_body_and_accepts_202 - notification = { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "req-1", reason: "user cancel" }, - } - - stub_request(:post, url).with(body: notification.to_json).to_return(status: 202, body: "") - - result = client.send_notification(notification: notification) - - assert_nil(result, "send_notification must return nil") - end - - def test_send_notification_surfaces_faraday_errors - notification = { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "req-1" }, - } - - stub_request(:post, url).to_return(status: 500) - - error = assert_raises(RequestHandlerError) do - client.send_notification(notification: notification) - end - - assert_equal(:internal_error, error.error_type) - assert_match(%r{notifications/cancelled}, error.message) - end - private - def initialize_session - stub_request(:post, url) - .to_return( - status: 200, - headers: { - "Content-Type" => "application/json", - "Mcp-Session-Id" => "session-abc", - }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - - client.send_request(request: { jsonrpc: "2.0", id: "1", method: "initialize" }) - end - - def stub_initialize - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "initialize" } - .to_return( - status: 200, - headers: { "Content-Type" => "application/json", "Mcp-Session-Id" => "session-abc" }, - body: { result: { protocolVersion: "2025-11-25" } }.to_json, - ) - end - - def stub_notification - stub_request(:post, url) - .with { |req| JSON.parse(req.body)["method"] == "notifications/initialized" } - .to_return(status: 202, body: "") - end - - def stub_discover - stub_request(:post, url).with do |req| - JSON.parse(req.body)["method"] == "server/discover" - end.to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: { - result: { - supportedVersions: ["2026-07-28"], - capabilities: { tools: {} }, - _meta: { "io.modelcontextprotocol/serverInfo": { name: "test-server", version: "1.0" } }, - ttlMs: 0, - cacheScope: "private", - }, - }.to_json, - ) - end - def stub_request(method, url) WebMock.stub_request(method, url) end - # Polls until the block is truthy; the listener runs on a background - # thread, so its requests are observed asynchronously. - def wait_until(timeout: 5) - deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + timeout - until yield - flunk("Timed out waiting for condition") if Process.clock_gettime(Process::CLOCK_MONOTONIC) > deadline - sleep(0.01) - end - end - - def requested?(stub) - WebMock::RequestRegistry.instance.times_executed(stub.request_pattern).positive? - end - - # Builds an `HTTP` client over the Faraday test adapter for the SEP-2243 mirroring tests: - # the stub serves `server/discover` (so `connect(mode: :modern)` works), answers `tools/list` - # with `tools` (an Array, or a Proc returning the listing per request), and captures - # the request headers of any other POST via `on_call`. - def mcp_param_test_client(tools:, on_call:) - stubs = Faraday::Adapter::Test::Stubs.new do |stub| - stub.post("/") do |env| - case JSON.parse(env.request_body)["method"] - when "server/discover" - discover = { supportedVersions: ["2026-07-28"], capabilities: { tools: {} }, ttlMs: 0, cacheScope: "private" } - [200, { "Content-Type" => "application/json" }, { result: discover }.to_json] - when "tools/list" - listing = tools.respond_to?(:call) ? tools.call : tools - [200, { "Content-Type" => "application/json" }, { result: { tools: listing } }.to_json] - else - on_call.call(env.request_headers) - [200, { "Content-Type" => "application/json" }, { result: { content: [] } }.to_json] - end - end - end - HTTP.new(url: url) { |faraday| faraday.adapter(:test, stubs) } - end - - def mcp_param_annotated_tool - { - name: "test_custom_headers", - inputSchema: { - type: "object", - properties: { - region: { type: "string", "x-mcp-header": "Region" }, - priority: { type: "integer", "x-mcp-header": "Priority" }, - non_ascii_val: { type: "string", "x-mcp-header": "NonAsciiVal" }, - null_val: { type: "string", "x-mcp-header": "NullVal" }, - }, - }, - } - end - def url "http://example.com" end @@ -2605,35 +282,6 @@ module MCP def client @client ||= HTTP.new(url: url) end - - # The SEP-1699 reconnection exchange: a `tools/call` whose SSE stream carries a priming event - # and the given `retry:` before closing, and a GET that replays the result for `Last-Event-ID`. - def reconnection_request - { - jsonrpc: "2.0", - id: "test_id", - method: "tools/call", - params: { name: "test_reconnection", arguments: {} }, - } - end - - def stub_reconnection_with_retry(retry_ms) - stub_request(:post, url).with( - body: reconnection_request.to_json, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: "id: event-1\nretry: #{retry_ms}\ndata:\n\n", - ) - - stub_request(:get, url).with( - headers: { "Last-Event-ID" => "event-1" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "text/event-stream" }, - body: %(data: {"jsonrpc":"2.0","id":"test_id","result":{"content":[]}}\n\n), - ) - end end end end diff --git a/test/mcp/client/mcp_param_headers_test.rb b/test/mcp/client/mcp_param_headers_test.rb deleted file mode 100644 index 639a0ab..0000000 --- a/test/mcp/client/mcp_param_headers_test.rb +++ /dev/null @@ -1,208 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/mcp_param_headers" - -module MCP - class Client - class McpParamHeadersTest < Minitest::Test - def test_scan_collects_declarations_from_properties - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { - "region" => { "type" => "string", "x-mcp-header" => "Region" }, - "priority" => { "type" => "integer", "x-mcp-header" => "Priority" }, - "verbose" => { "type" => "boolean", "x-mcp-header" => "Verbose" }, - "plain" => { "type" => "string" }, - }, - }) - - assert(scan[:valid]) - assert_equal( - [ - { path: ["region"], header_name: "Region", type: "string" }, - { path: ["priority"], header_name: "Priority", type: "integer" }, - { path: ["verbose"], header_name: "Verbose", type: "boolean" }, - ], - scan[:declarations], - ) - end - - def test_scan_collects_nested_declarations_and_symbol_keys - scan = McpParamHeaders.scan({ - type: "object", - properties: { - options: { - type: "object", - properties: { - region: { type: "string", "x-mcp-header": "Region" }, - }, - }, - }, - }) - - assert(scan[:valid]) - assert_equal([{ path: ["options", "region"], header_name: "Region", type: "string" }], scan[:declarations]) - end - - def test_scan_accepts_number_typed_declarations - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { "float_val" => { "type" => "number", "x-mcp-header" => "FloatVal" } }, - }) - - assert(scan[:valid]) - assert_equal("number", scan[:declarations].first[:type]) - end - - def test_scan_rejects_an_annotation_at_the_schema_root - scan = McpParamHeaders.scan({ "type" => "object", "x-mcp-header" => "Root" }) - - refute(scan[:valid]) - assert_includes(scan[:reason], "statically reachable") - end - - def test_scan_rejects_annotations_under_non_reachable_keywords - ["oneOf", "items", "$defs"].each do |keyword| - nested = { "type" => "string", "x-mcp-header" => "Hidden" } - sub = keyword == "$defs" ? { "entry" => nested } : [nested] - scan = McpParamHeaders.scan({ "type" => "object", keyword => sub }) - - refute(scan[:valid], "expected the annotation under #{keyword} to invalidate the schema") - end - end - - def test_scan_rejects_empty_and_non_string_annotations - ["", 42].each do |annotation| - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { "value" => { "type" => "string", "x-mcp-header" => annotation } }, - }) - - refute(scan[:valid]) - assert_includes(scan[:reason], "non-empty string") - end - end - - def test_scan_rejects_non_token_annotation_names - ["has space", "colon:name", "日本語", "line\nbreak"].each do |annotation| - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { "value" => { "type" => "string", "x-mcp-header" => annotation } }, - }) - - refute(scan[:valid], "expected #{annotation.inspect} to be rejected") - assert_includes(scan[:reason], "RFC 9110") - end - end - - def test_scan_rejects_non_primitive_declaring_properties - [{ "type" => "object" }, { "type" => "array" }, {}].each do |extra| - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { "value" => extra.merge("x-mcp-header" => "Value") }, - }) - - refute(scan[:valid]) - assert_includes(scan[:reason], "primitive-typed") - end - end - - def test_scan_rejects_case_insensitively_duplicated_names - scan = McpParamHeaders.scan({ - "type" => "object", - "properties" => { - "one" => { "type" => "string", "x-mcp-header" => "Region" }, - "two" => { "type" => "string", "x-mcp-header" => "REGION" }, - }, - }) - - refute(scan[:valid]) - assert_includes(scan[:reason], "case-insensitively unique") - end - - def test_primitive_to_string_conversions - assert_equal("us-west1", McpParamHeaders.primitive_to_string("us-west1")) - assert_equal("true", McpParamHeaders.primitive_to_string(true)) - assert_equal("false", McpParamHeaders.primitive_to_string(false)) - assert_equal("42", McpParamHeaders.primitive_to_string(42)) - assert_equal("42", McpParamHeaders.primitive_to_string(42.0)) - assert_equal("3.14159", McpParamHeaders.primitive_to_string(3.14159)) - assert_nil(McpParamHeaders.primitive_to_string(2**53 + 1)) - assert_nil(McpParamHeaders.primitive_to_string(Float::INFINITY)) - assert_nil(McpParamHeaders.primitive_to_string({ "nested" => true })) - end - - def test_encode_value_passes_safe_ascii_through - assert_equal("us-west1", McpParamHeaders.encode_value("us-west1")) - assert_equal("SELECT * FROM users", McpParamHeaders.encode_value("SELECT * FROM users")) - end - - def test_encode_value_wraps_unsafe_values_in_the_base64_sentinel - { - "" => "", - "Hello, 世界" => "Hello, 世界", - " padded " => " padded ", - "\tindented" => "\tindented", - "line1\nline2" => "line1\nline2", - "line1\r\nline2" => "line1\r\nline2", - "=?base64?Zm9v?=" => "=?base64?Zm9v?=", - }.each do |raw, decoded| - encoded = McpParamHeaders.encode_value(raw) - - assert_match(/\A=\?base64\?.*\?=\z/, encoded, "expected #{raw.inspect} to be wrapped") - payload = encoded.delete_prefix("=?base64?").delete_suffix("?=") - assert_equal(decoded, payload.unpack1("m0").force_encoding(Encoding::UTF_8)) - end - end - - def test_build_mirrors_declared_arguments_into_prefixed_headers - declarations = [ - { path: ["region"], header_name: "Region", type: "string" }, - { path: ["priority"], header_name: "Priority", type: "integer" }, - { path: ["method_val"], header_name: "Method", type: "string" }, - ] - - headers = McpParamHeaders.build(declarations, { "region" => "us-west1", priority: 42, "method_val" => "test-method" }) - - assert_equal( - { - "Mcp-Param-Region" => "us-west1", - "Mcp-Param-Priority" => "42", - "Mcp-Param-Method" => "test-method", - }, - headers, - ) - end - - def test_build_omits_null_absent_and_non_primitive_values - declarations = [ - { path: ["null_val"], header_name: "NullVal", type: "string" }, - { path: ["absent"], header_name: "Absent", type: "string" }, - { path: ["object_val"], header_name: "ObjectVal", type: "string" }, - ] - - headers = McpParamHeaders.build(declarations, { "null_val" => nil, "object_val" => { "a" => 1 } }) - - assert_empty(headers) - end - - def test_build_reads_nested_paths - declarations = [{ path: ["options", "region"], header_name: "Region", type: "string" }] - - headers = McpParamHeaders.build(declarations, { "options" => { "region" => "us-east1" } }) - - assert_equal({ "Mcp-Param-Region" => "us-east1" }, headers) - end - - def test_build_omits_values_that_cannot_be_represented_as_utf_8 - declarations = [{ path: ["blob"], header_name: "Blob", type: "string" }] - binary = (+"\xff\xfe").force_encoding(Encoding::ASCII_8BIT) - - headers = McpParamHeaders.build(declarations, { "blob" => binary }) - - assert_empty(headers) - end - end - end -end diff --git a/test/mcp/client/oauth/bounded_body_test.rb b/test/mcp/client/oauth/bounded_body_test.rb deleted file mode 100644 index aeaf118..0000000 --- a/test/mcp/client/oauth/bounded_body_test.rb +++ /dev/null @@ -1,150 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "faraday" -require "socket" -require "stringio" -require "zlib" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class BoundedBodyTest < Minitest::Test - def test_on_data_rejects_chunks_that_together_exceed_the_limit - bounded = bounded_body(max_bytes: 64) - - error = assert_raises(too_large_error) do - 4.times do - bounded.on_data.call("a" * 32, 32, nil) - end - end - - assert_includes(error.message, "exceeds 64 bytes") - end - - def test_on_data_accepts_a_body_that_stops_at_the_limit - bounded = bounded_body(max_bytes: 64) - - 2.times do - bounded.on_data.call("a" * 32, 32, nil) - end - - assert_equal("a" * 64, bounded.response_for(stub_response(body: "")).body) - end - - def test_response_for_rejects_an_over_limit_body_when_the_adapter_did_not_stream - bounded = bounded_body(max_bytes: 64) - - error = assert_raises(too_large_error) do - bounded.response_for(stub_response(body: "a" * 65)) - end - - assert_includes(error.message, "exceeds 64 bytes") - end - - def test_response_for_falls_back_to_the_response_body_when_the_adapter_did_not_stream - bounded = bounded_body(max_bytes: 64) - - assert_equal("a" * 64, bounded.response_for(stub_response(body: "a" * 64)).body) - end - - def test_response_for_coerces_a_non_string_body - bounded = bounded_body(max_bytes: 64) - - assert_equal("", bounded.response_for(stub_response(body: nil)).body) - end - - def test_response_for_carries_the_status_through - bounded = bounded_body(max_bytes: 64) - - assert_equal(404, bounded.response_for(stub_response(status: 404, body: "")).status) - end - - # Served over a real socket rather than WebMock: WebMock hands back the stubbed body verbatim - # whatever its `Content-Encoding`, so the adapter's inflater never runs and a stubbed version - # of this test would assert the opposite of what it looks like. - def test_the_cap_counts_decompressed_bytes - bounded = bounded_body(max_bytes: 1024 * 1024) - compressed = gzip("a" * (5 * 1024 * 1024)) - - assert_operator(compressed.bytesize, :<, 1024 * 1024, "the compressed body must fit under the cap") - - serving_gzip(compressed) do |url| - assert_raises(too_large_error) do - Faraday.new.get(url) do |req| - req.options.on_data = bounded.on_data - req.options.timeout = 5 - end - end - end - end - - private - - def gzip(content) - io = StringIO.new - - writer = Zlib::GzipWriter.new(io) - writer.write(content) - writer.close - - io.string - end - - def serving_gzip(body) - # Other test files load `webmock/minitest`, which blocks real connections process-wide. - # This is the one place that needs the adapter's own request path. - WebMock.disable! if defined?(WebMock) - - server = TCPServer.new("127.0.0.1", 0) - thread = Thread.new do - socket = server.accept - - loop do - line = socket.gets - - break if line.nil? || line == "\r\n" - end - - socket.write( - "HTTP/1.1 200 OK\r\n" \ - "Content-Type: application/json\r\n" \ - "Content-Encoding: gzip\r\n" \ - "Content-Length: #{body.bytesize}\r\n" \ - "Connection: close\r\n\r\n", - ) - socket.write(body) - - socket.close - rescue IOError, SystemCallError - nil - end - - # Scoped to start after both are assigned, so the cleanup below never runs against `nil` - # and a failure to open the socket surfaces as itself rather than as a `NoMethodError`. - begin - yield("http://127.0.0.1:#{server.addr[1]}/") - ensure - thread.kill - server.close - end - ensure - WebMock.enable! if defined?(WebMock) - end - - def bounded_body(max_bytes:) - OAuth.const_get(:BoundedBody).new(max_bytes: max_bytes) - end - - def too_large_error - OAuth.const_get(:BoundedBody)::TooLargeError - end - - def stub_response(body:, status: 200) - Struct.new(:status, :body).new(status, body) - end - end - end - end -end diff --git a/test/mcp/client/oauth/client_credentials_provider_test.rb b/test/mcp/client/oauth/client_credentials_provider_test.rb deleted file mode 100644 index 6c679e3..0000000 --- a/test/mcp/client/oauth/client_credentials_provider_test.rb +++ /dev/null @@ -1,286 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class ClientCredentialsProviderTest < Minitest::Test - # Every parameter the flow sets on a token request, spelled out rather than read from - # `Flow::RESERVED_TOKEN_REQUEST_PARAMS`, so a key dropped from that constant fails here. - RESERVED_TOKEN_REQUEST_PARAMS = [ - "grant_type", - "client_id", - "client_secret", - "client_assertion", - "client_assertion_type", - "scope", - "resource", - "code", - "code_verifier", - "redirect_uri", - "refresh_token", - "assertion", - ].freeze - - def test_initialize_stores_credentials_as_client_information - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret") - - info = provider.client_information - assert_equal("cc-client", info["client_id"]) - assert_equal("cc-secret", info["client_secret"]) - assert_equal("client_secret_basic", info["token_endpoint_auth_method"]) - end - - def test_authorization_flow_is_client_credentials - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret") - - assert_equal(:client_credentials, provider.authorization_flow) - end - - def test_initialize_accepts_client_secret_post - provider = ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - token_endpoint_auth_method: "client_secret_post", - ) - - assert_equal("client_secret_post", provider.client_information["token_endpoint_auth_method"]) - end - - def test_initialize_keeps_the_http_client_customizer - customizer = ->(_faraday) {} - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", http_client_customizer: customizer) - - assert_same(customizer, provider.http_client_customizer) - assert_nil(ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret").http_client_customizer) - end - - def test_initialize_rejects_a_non_callable_http_client_customizer_before_writing_credentials - storage = InMemoryStorage.new - - error = assert_raises(ArgumentError) do - ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", storage: storage, http_client_customizer: "recorder") - end - - assert_equal("http_client_customizer must respond to call (got String).", error.message) - assert_nil(storage.client_information) - end - - def test_initialize_rejects_missing_client_id - ["", " ", nil].each do |value| - assert_raises(ClientCredentialsProvider::InvalidCredentialsError, "should reject #{value.inspect}") do - ClientCredentialsProvider.new(client_id: value, client_secret: "cc-secret") - end - end - end - - def test_initialize_rejects_missing_client_secret - # The client_credentials grant is for confidential clients, so a credential is mandatory. - ["", " ", nil].each do |value| - assert_raises(ClientCredentialsProvider::InvalidCredentialsError, "should reject #{value.inspect}") do - ClientCredentialsProvider.new(client_id: "cc-client", client_secret: value) - end - end - end - - def test_initialize_rejects_none_auth_method - # An unauthenticated client_credentials request is meaningless. - assert_raises(ClientCredentialsProvider::InvalidCredentialsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - token_endpoint_auth_method: "none", - ) - end - end - - def test_token_helpers_delegate_to_storage - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret") - provider.save_tokens("access_token" => "cc-token") - - assert_equal("cc-token", provider.access_token) - provider.clear_tokens! - assert_nil(provider.tokens) - end - - # `OpenSSL::PKey::EC.generate` only exists from the openssl gem 2.2 (Ruby 3.0), - # while `EC#generate_key` raises on openssl 3.0+ where PKey objects are immutable, - # so branch on availability to keep CI green on every supported Ruby. - def generate_es256_key - if OpenSSL::PKey::EC.respond_to?(:generate) - OpenSSL::PKey::EC.generate("prime256v1") - else - OpenSSL::PKey::EC.new("prime256v1").tap(&:generate_key) - end - end - - def private_key_jwt_provider(key: generate_es256_key) - ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - private_key: key, - signing_algorithm: "ES256", - ) - end - - def test_initialize_accepts_private_key_jwt - provider = private_key_jwt_provider - - info = provider.client_information - assert_equal("cc-client", info["client_id"]) - assert_equal("private_key_jwt", info["token_endpoint_auth_method"]) - end - - def test_initialize_private_key_jwt_does_not_persist_the_key_or_a_secret - # The PEM must never reach a (potentially persistent) storage backend. - provider = private_key_jwt_provider - - info = provider.client_information - refute(info.key?("client_secret")) - refute(info.values.any? { |value| value.to_s.include?("PRIVATE KEY") }) - end - - def test_initialize_private_key_jwt_requires_private_key - assert_raises(ClientCredentialsProvider::InvalidCredentialsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - signing_algorithm: "ES256", - ) - end - end - - def test_initialize_private_key_jwt_requires_signing_algorithm - assert_raises(ClientCredentialsProvider::InvalidCredentialsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - private_key: generate_es256_key, - ) - end - end - - def test_initialize_private_key_jwt_rejects_client_secret - assert_raises(ClientCredentialsProvider::InvalidCredentialsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - token_endpoint_auth_method: "private_key_jwt", - private_key: generate_es256_key, - signing_algorithm: "ES256", - ) - end - end - - def test_initialize_private_key_jwt_fails_fast_on_key_algorithm_mismatch - assert_raises(JWTClientAssertion::InvalidKeyError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - private_key: OpenSSL::PKey::RSA.new(2048), - signing_algorithm: "ES256", - ) - end - end - - def test_client_assertion_returns_signed_jwt_for_the_audience - provider = private_key_jwt_provider - - assertion = provider.client_assertion(audience: "https://auth.example.com") - payload_segment = assertion.split(".")[1] - claims = JSON.parse(Base64.urlsafe_decode64(payload_segment + "=" * (-payload_segment.length % 4))) - - assert_equal("cc-client", claims["iss"]) - assert_equal("cc-client", claims["sub"]) - assert_equal("https://auth.example.com", claims["aud"]) - end - - def test_token_request_params_is_nil_by_default - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret") - - assert_nil(provider.token_request_params) - end - - def test_initialize_keeps_a_frozen_copy_of_token_request_params - params = { "audience" => +"https://api.example.com" } - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", token_request_params: params) - - params["audience"] << "/changed" - params["organization"] = "org_123" - - assert_equal({ "audience" => "https://api.example.com" }, provider.token_request_params) - assert_predicate(provider.token_request_params, :frozen?) - assert_predicate(provider.token_request_params["audience"], :frozen?) - end - - def test_initialize_rejects_token_request_params_that_the_sdk_sets_itself - RESERVED_TOKEN_REQUEST_PARAMS.each do |key| - error = assert_raises(Flow::InvalidTokenRequestParamsError, "should reject #{key.inspect}") do - ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", token_request_params: { key => "x" }) - end - - assert_includes(error.message, key.inspect) - end - end - - def test_initialize_rejects_token_request_params_that_are_not_a_hash_of_strings - ["audience=x", { audience: "x" }, { "audience" => 1 }, { "audience" => nil }].each do |params| - assert_raises(Flow::InvalidTokenRequestParamsError, "should reject #{params.inspect}") do - ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", token_request_params: params) - end - end - end - - def test_initialize_rejects_token_request_params_that_compare_keys_by_identity - # Two equal keys are two entries in such a Hash and would silently collapse into one when copied. - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - token_request_params: { "audience" => "x" }.compare_by_identity, - ) - end - - assert_match(/identity/, error.message) - end - - def test_initialize_copies_keys_that_hash_would_share_with_the_caller - # `Hash` copies and freezes only keys whose class is exactly `String`; a subclass key would otherwise - # stay shared with the caller, and a later `replace` would turn it into a reserved name. - key = Class.new(String).new("audience") - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", token_request_params: { key => "x" }) - - key.replace("grant_type") - - assert_equal({ "audience" => "x" }, provider.token_request_params) - refute_same(key, provider.token_request_params.keys.first) - assert_predicate(provider.token_request_params.keys.first, :frozen?) - end - - def test_initialize_keeps_empty_token_request_params_as_a_frozen_empty_hash - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", token_request_params: {}) - - assert_equal({}, provider.token_request_params) - assert_predicate(provider.token_request_params, :frozen?) - end - - def test_initialize_writes_no_client_information_when_token_request_params_are_rejected - storage = InMemoryStorage.new - - assert_raises(Flow::InvalidTokenRequestParamsError) do - ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - storage: storage, - token_request_params: { "grant_type" => "password" }, - ) - end - - assert_nil(storage.client_information) - end - end - end - end -end diff --git a/test/mcp/client/oauth/cross_app_access_provider_test.rb b/test/mcp/client/oauth/cross_app_access_provider_test.rb deleted file mode 100644 index ed49b47..0000000 --- a/test/mcp/client/oauth/cross_app_access_provider_test.rb +++ /dev/null @@ -1,160 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class CrossAppAccessProviderTest < Minitest::Test - def build_provider(assertion_provider: ->(**) { "id-jag" }) - CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: assertion_provider, - ) - end - - def test_initialize_stores_credentials_with_basic_auth_method - provider = build_provider - - info = provider.client_information - assert_equal("xaa-client", info["client_id"]) - assert_equal("xaa-secret", info["client_secret"]) - assert_equal("client_secret_basic", info["token_endpoint_auth_method"]) - end - - def test_authorization_flow_is_jwt_bearer - assert_equal(:jwt_bearer, build_provider.authorization_flow) - end - - def test_jwt_bearer_assertion_passes_audience_and_resource_through - received = nil - provider = build_provider( - assertion_provider: ->(audience:, resource:) { - received = { audience: audience, resource: resource } - "id-jag-assertion" - }, - ) - - assertion = provider.jwt_bearer_assertion( - audience: "https://auth.example.com", - resource: "https://srv.example.com/mcp", - ) - - assert_equal("id-jag-assertion", assertion) - assert_equal( - { audience: "https://auth.example.com", resource: "https://srv.example.com/mcp" }, - received, - ) - end - - def test_initialize_keeps_the_http_client_customizer - customizer = ->(_faraday) {} - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag" }, - http_client_customizer: customizer, - ) - - assert_same(customizer, provider.http_client_customizer) - assert_nil(build_provider.http_client_customizer) - end - - def test_initialize_rejects_a_non_callable_http_client_customizer_before_writing_credentials - storage = InMemoryStorage.new - - error = assert_raises(ArgumentError) do - CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag" }, - storage: storage, - http_client_customizer: "recorder", - ) - end - - assert_equal("http_client_customizer must respond to call (got String).", error.message) - assert_nil(storage.client_information) - end - - def test_initialize_rejects_missing_client_id - assert_raises(CrossAppAccessProvider::InvalidConfigurationError) do - CrossAppAccessProvider.new( - client_id: " ", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag" }, - ) - end - end - - def test_initialize_rejects_missing_client_secret - # SEP-990 authenticates the jwt-bearer grant with client_secret_basic. - assert_raises(CrossAppAccessProvider::InvalidConfigurationError) do - CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: nil, - assertion_provider: ->(**) { "id-jag" }, - ) - end - end - - def test_initialize_rejects_non_callable_assertion_provider - assert_raises(CrossAppAccessProvider::InvalidConfigurationError) do - CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: "not callable", - ) - end - end - - def test_token_helpers_delegate_to_storage - provider = build_provider - provider.save_tokens("access_token" => "xaa-token") - - assert_equal("xaa-token", provider.access_token) - provider.clear_tokens! - assert_nil(provider.tokens) - end - - def test_token_request_params_is_nil_by_default - assert_nil(build_provider.token_request_params) - end - - def test_initialize_keeps_a_frozen_copy_of_token_request_params - params = { "audience" => +"https://api.example.com" } - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag" }, - token_request_params: params, - ) - - params["audience"] << "/changed" - - assert_equal({ "audience" => "https://api.example.com" }, provider.token_request_params) - assert_predicate(provider.token_request_params, :frozen?) - end - - def test_initialize_writes_no_client_information_when_token_request_params_are_rejected - storage = InMemoryStorage.new - - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag" }, - storage: storage, - token_request_params: { "assertion" => "x" }, - ) - end - - assert_includes(error.message, '"assertion"') - assert_nil(storage.client_information) - end - end - end - end -end diff --git a/test/mcp/client/oauth/discovery_test.rb b/test/mcp/client/oauth/discovery_test.rb deleted file mode 100644 index d58c7f2..0000000 --- a/test/mcp/client/oauth/discovery_test.rb +++ /dev/null @@ -1,727 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/oauth/discovery" - -module MCP - class Client - module OAuth - class DiscoveryTest < Minitest::Test - def test_parse_www_authenticate_with_quoted_resource_metadata - header = 'Bearer error="invalid_token", error_description="Missing", ' \ - 'resource_metadata="https://srv.example.com/.well-known/oauth-protected-resource/mcp"' - params = Discovery.parse_www_authenticate(header) - - assert_equal("invalid_token", params["error"]) - assert_equal("Missing", params["error_description"]) - assert_equal("https://srv.example.com/.well-known/oauth-protected-resource/mcp", params["resource_metadata"]) - end - - def test_parse_www_authenticate_returns_empty_for_other_schemes - assert_empty(Discovery.parse_www_authenticate('Basic realm="x"')) - end - - def test_parse_www_authenticate_returns_empty_for_nil - assert_empty(Discovery.parse_www_authenticate(nil)) - end - - def test_parse_www_authenticate_finds_bearer_after_other_scheme - header = 'Basic realm="x", Bearer error="invalid_token", resource_metadata="https://srv/x"' - params = Discovery.parse_www_authenticate(header) - - assert_equal("invalid_token", params["error"]) - assert_equal("https://srv/x", params["resource_metadata"]) - end - - def test_parse_www_authenticate_stops_at_following_scheme - header = 'Bearer error="invalid_token", resource_metadata="https://srv/x", DPoP algs="ES256"' - params = Discovery.parse_www_authenticate(header) - - assert_equal("invalid_token", params["error"]) - assert_equal("https://srv/x", params["resource_metadata"]) - refute(params.key?("algs")) - end - - def test_parse_www_authenticate_returns_empty_when_bearer_absent - assert_empty(Discovery.parse_www_authenticate('DPoP algs="ES256"')) - end - - def test_parse_www_authenticate_handles_bare_bearer - assert_empty(Discovery.parse_www_authenticate("Bearer")) - end - - def test_parse_www_authenticate_handles_tab_separator - params = Discovery.parse_www_authenticate(%(Bearer\terror="invalid_token",\tresource_metadata="https://srv/x")) - - assert_equal("invalid_token", params["error"]) - assert_equal("https://srv/x", params["resource_metadata"]) - end - - def test_parse_www_authenticate_tolerates_trailing_comma - params = Discovery.parse_www_authenticate('Bearer error="invalid_token", resource_metadata="https://srv/x",') - - assert_equal("invalid_token", params["error"]) - assert_equal("https://srv/x", params["resource_metadata"]) - end - - def test_parse_www_authenticate_handles_quoted_value_with_comma_and_spaces - params = Discovery.parse_www_authenticate('Bearer error_description="missing, expired, or revoked token"') - - assert_equal("missing, expired, or revoked token", params["error_description"]) - end - - def test_parse_www_authenticate_unescapes_quoted_pair - # Per RFC 7230 Section 3.2.6, a backslash inside a quoted-string escapes - # the next character. The parser must surface the unescaped form. - header = 'Bearer error_description="value with \"quoted\" word and a back\\\\slash"' - params = Discovery.parse_www_authenticate(header) - - assert_equal('value with "quoted" word and a back\\slash', params["error_description"]) - end - - def test_protected_resource_metadata_urls_uses_explicit_url_first - urls = Discovery.protected_resource_metadata_urls( - server_url: "https://api.example.com/mcp", - resource_metadata_url: "https://api.example.com/.well-known/oauth-protected-resource/mcp", - ) - - assert_equal("https://api.example.com/.well-known/oauth-protected-resource/mcp", urls.first) - assert_includes(urls, "https://api.example.com/.well-known/oauth-protected-resource") - end - - def test_protected_resource_metadata_urls_falls_back_to_path_then_root - urls = Discovery.protected_resource_metadata_urls(server_url: "https://api.example.com/mcp") - - assert_equal( - [ - "https://api.example.com/.well-known/oauth-protected-resource/mcp", - "https://api.example.com/.well-known/oauth-protected-resource", - ], - urls, - ) - end - - def test_authorization_server_metadata_urls_for_root_issuer - urls = Discovery.authorization_server_metadata_urls("https://auth.example.com") - - assert_equal( - [ - "https://auth.example.com/.well-known/oauth-authorization-server", - "https://auth.example.com/.well-known/openid-configuration", - ], - urls, - ) - end - - def test_authorization_server_metadata_urls_for_path_issuer - urls = Discovery.authorization_server_metadata_urls("https://auth.example.com/tenant1") - - assert_includes(urls, "https://auth.example.com/.well-known/oauth-authorization-server/tenant1") - assert_includes(urls, "https://auth.example.com/.well-known/openid-configuration/tenant1") - assert_includes(urls, "https://auth.example.com/tenant1/.well-known/openid-configuration") - end - - # Per SEP-2351, MCP explicitly uses the RFC 8414 default `oauth-authorization-server` well-known URI suffix - # and defines no application-specific suffix. The first probed candidate for a root issuer must be exactly - # that default suffix. - def test_authorization_server_metadata_urls_probe_rfc8414_default_suffix_first - urls = Discovery.authorization_server_metadata_urls("https://auth.example.com") - - assert_equal("https://auth.example.com/.well-known/oauth-authorization-server", urls.first) - end - - def test_authorization_server_metadata_urls_use_only_registered_well_known_suffixes - root_urls = Discovery.authorization_server_metadata_urls("https://auth.example.com") - path_urls = Discovery.authorization_server_metadata_urls("https://auth.example.com/tenant1") - - (root_urls + path_urls).each do |url| - suffix = url[%r{/\.well-known/([^/]+)}, 1] - - assert_includes( - ["oauth-authorization-server", "openid-configuration"], suffix, "unexpected well-known suffix in #{url}" - ) - end - end - - def test_authorization_server_metadata_urls_put_path_inserted_oauth_candidate_first_for_path_issuer - urls = Discovery.authorization_server_metadata_urls("https://auth.example.com/tenant1") - - assert_equal("https://auth.example.com/.well-known/oauth-authorization-server/tenant1", urls.first) - end - - def test_authorization_server_metadata_urls_treat_trailing_slash_issuer_as_root - urls = Discovery.authorization_server_metadata_urls("https://auth.example.com/") - - assert_equal( - ["https://auth.example.com/.well-known/oauth-authorization-server", "https://auth.example.com/.well-known/openid-configuration"], - urls, - ) - end - - def test_infer_application_type_returns_native_for_loopback_http_redirect_uris - uris = ["http://localhost:0/callback", "http://127.0.0.1:8080/cb", "http://[::1]/cb"] - - assert_equal("native", Discovery.infer_application_type(uris)) - end - - def test_infer_application_type_returns_native_for_custom_scheme_redirect_uris - assert_equal("native", Discovery.infer_application_type(["com.example.app:/oauth/callback"])) - end - - def test_infer_application_type_returns_web_for_https_redirect_uris - assert_equal("web", Discovery.infer_application_type(["https://app.example.com/callback"])) - end - - def test_infer_application_type_returns_web_when_any_redirect_uri_is_not_native - uris = ["http://localhost:0/callback", "https://app.example.com/callback"] - - assert_equal("web", Discovery.infer_application_type(uris)) - end - - def test_infer_application_type_returns_web_for_localhost_lookalike_host - assert_equal("web", Discovery.infer_application_type(["http://localhost.example.com/cb"])) - end - - def test_infer_application_type_returns_web_for_nil_or_empty_redirect_uris - assert_equal("web", Discovery.infer_application_type(nil)) - assert_equal("web", Discovery.infer_application_type([])) - end - - def test_infer_application_type_returns_web_for_unparseable_redirect_uri - assert_equal("web", Discovery.infer_application_type(["http://[invalid"])) - end - - def test_canonicalize_url_normalizes_scheme_host_port_and_path - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("HTTPS://Srv.Example.COM:443/mcp#frag"), - ) - assert_equal( - "http://srv.example.com", - Discovery.canonicalize_url("http://Srv.Example.COM:80/"), - ) - assert_equal( - "https://srv.example.com:8443/mcp", - Discovery.canonicalize_url("https://srv.example.com:8443/mcp"), - ) - end - - def test_canonicalize_url_resolves_dot_segments - # Critical for audience binding: an attacker-supplied URL like - # `/api/../mcp` must collapse to `/mcp` so it cannot pass a PRM check - # whose `resource` is the more privileged `/api` path. - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/api/../mcp"), - ) - assert_equal( - "https://srv.example.com/api/mcp", - Discovery.canonicalize_url("https://srv.example.com/api/./mcp"), - ) - assert_equal( - "https://srv.example.com/bar", - Discovery.canonicalize_url("https://srv.example.com/foo/../../bar"), - ) - assert_equal( - "https://srv.example.com", - Discovery.canonicalize_url("https://srv.example.com/api/.."), - ) - end - - def test_canonicalize_url_resolves_percent_encoded_dot_segments - # `%2e` and `%2E` are percent-encoded forms of `.` (RFC 3986 Section 6.2.2.2) - # and must be decoded *before* dot-segment resolution. Otherwise, - # an attacker-supplied URL like `/api/%2e%2e/mcp` would slip past - # `remove_dot_segments` and escape the PRM `resource=/api` audience - # binding. - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/api/%2e%2e/mcp"), - ) - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/api/%2E%2E/mcp"), - ) - assert_equal( - "https://srv.example.com/api/mcp", - Discovery.canonicalize_url("https://srv.example.com/api/%2e/mcp"), - ) - end - - def test_canonicalize_url_drops_userinfo - # The canonicalized URL is sent on the wire as the RFC 8707 `resource` - # claim and is surfaced in error messages, so credentials in - # the authority must never round-trip: dropping `user:pass@` keeps them - # from leaking to the authorization server or to log destinations. - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://user:pass@Srv.Example.COM:443/api/../mcp"), - ) - end - - def test_redact_url_drops_credentials_query_and_fragment_but_keeps_the_spelling - # Reported next to a failed request, the URL must still match the server's access log, so the host - # and path are left alone: no lowercasing of the host, no dot-segment resolution, no decoding. - assert_equal( - "https://Srv.Example.COM:8443/tenant/%2e%2e/prm%2Ejson", - Discovery.redact_url("https://user:pass@Srv.Example.COM:8443/tenant/%2e%2e/prm%2Ejson?token=abc#frag"), - ) - end - - def test_redact_url_does_not_echo_a_url_it_cannot_parse - assert_equal("[unparseable URL]", Discovery.redact_url("https://user:pass@srv.example.com/pr m.json?token=abc")) - end - - def test_canonicalize_url_normalizes_query_to_match_faraday - # Faraday rewrites `env.url` before sending a request: it sorts - # parameters by name, uppercases percent-encoded hex, and drops - # a bare `?` with no parameters. The canonical form must apply - # the same transformation so the URL guard does not raise a false - # positive on every valid request with a query string. - assert_equal( - "https://srv.example.com/mcp?a=1&b=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?b=2&a=1"), - ) - assert_equal( - "https://srv.example.com/mcp?x=%2F", - Discovery.canonicalize_url("https://srv.example.com/mcp?x=%2f"), - ) - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/mcp?"), - ) - end - - def test_canonicalize_url_collapses_same_name_query_parameters - # Faraday's internal query encoder uses a Hash, so repeated keys - # collapse to the last value. The canonical form must apply - # the same collapse, otherwise the URL guard false-positives on URLs - # like `?a=1&a=2` (Faraday rewrites to `?a=2`). - assert_equal( - "https://srv.example.com/mcp?a=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?a=1&a=2"), - ) - assert_equal( - "https://srv.example.com/mcp?a=3&b=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?a=1&b=2&a=3"), - ) - assert_equal( - "https://srv.example.com/mcp?x=%2F", - Discovery.canonicalize_url("https://srv.example.com/mcp?x=%2f&x=%2F"), - ) - end - - def test_canonicalize_url_preserves_valueless_vs_empty_value_distinction - # Faraday preserves the difference between `?key` (no `=`) and - # `?key=` (empty value) exactly as the caller passed it. A naive - # `URI.decode_www_form` round-trip would collapse both to `?key=` - # and false-positive the URL guard / RFC 8707 `resource` check for - # any URL that uses the value-less form. - assert_equal( - "https://srv.example.com/mcp?tenant", - Discovery.canonicalize_url("https://srv.example.com/mcp?tenant"), - ) - assert_equal( - "https://srv.example.com/mcp?tenant=", - Discovery.canonicalize_url("https://srv.example.com/mcp?tenant="), - ) - assert_equal( - "https://srv.example.com/mcp?a=1&b", - Discovery.canonicalize_url("https://srv.example.com/mcp?a=1&b"), - ) - # Collapse with last-write-wins also keeps the `=` form of - # the surviving segment: `flag=1&flag` -> last is `flag` (no `=`), so - # the canonical form is `?flag`, matching Faraday. - assert_equal( - "https://srv.example.com/mcp?flag", - Discovery.canonicalize_url("https://srv.example.com/mcp?flag=1&flag"), - ) - end - - def test_canonicalize_url_preserves_array_form_repeated_keys - # Keys ending in `[]` are Faraday's array notation: the encoder - # preserves every occurrence in input order instead of collapsing - # them. The canonical form must do the same; otherwise a hijacked - # middleware that drops one entry from `?tenant[]=victim&tenant[]=...` - # would slip past the URL guard, and a legitimate - # `?roles[]=a&roles[]=b` URL would false-positive on the first - # request. - assert_equal( - "https://srv.example.com/mcp?a%5B%5D=1&a%5B%5D=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?a[]=1&a[]=2"), - ) - assert_equal( - "https://srv.example.com/mcp?tenant%5B%5D=evil&tenant%5B%5D=victim", - Discovery.canonicalize_url("https://srv.example.com/mcp?tenant[]=evil&tenant[]=victim"), - ) - assert_equal( - "https://srv.example.com/mcp?a%5B%5D=1&a%5B%5D=2&b=3", - Discovery.canonicalize_url("https://srv.example.com/mcp?a[]=1&a[]=2&b=3"), - ) - # Nested keys like `a[b]` are not array notation. They collapse with - # last-write-wins, matching Faraday's `NestedParamsEncoder`. - assert_equal( - "https://srv.example.com/mcp?a%5Bb%5D=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?a[b]=1&a[b]=2"), - ) - end - - def test_canonicalize_url_drops_empty_name_and_blank_query_segments - # Faraday's encoder treats pairs with an empty name and blank `&&` - # separators as no parameter at all. The canonical form must do - # the same; otherwise URLs like `?=v` or `?&&a=1&&` produce a snapshot - # that disagrees with the Faraday-rewritten effective URL and - # the request-time guard false-positives. - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/mcp?=v"), - ) - assert_equal( - "https://srv.example.com/mcp?a=1", - Discovery.canonicalize_url("https://srv.example.com/mcp?&&a=1&&"), - ) - assert_equal( - "https://srv.example.com/mcp?a=2", - Discovery.canonicalize_url("https://srv.example.com/mcp?a=1&&a=2"), - ) - assert_equal( - "https://srv.example.com/mcp?a=1", - Discovery.canonicalize_url("https://srv.example.com/mcp?=&=&a=1"), - ) - assert_equal( - "https://srv.example.com/mcp", - Discovery.canonicalize_url("https://srv.example.com/mcp?&"), - ) - end - - def test_resource_covers_blocks_dot_segment_bypass_after_canonicalization - server = Discovery.canonicalize_url("https://srv.example.com/api/../mcp") - prm = Discovery.canonicalize_url("https://srv.example.com/api") - - refute( - Discovery.resource_covers?(prm: prm, server: server), - "PRM `resource=/api` must not cover `/api/../mcp` after canonicalization", - ) - end - - def test_secure_url_accepts_https - assert(Discovery.secure_url?("https://srv.example.com/mcp")) - assert(Discovery.secure_url?("HTTPS://Srv.Example.COM/mcp")) - end - - def test_secure_url_accepts_loopback_http - assert(Discovery.secure_url?("http://localhost/x")) - assert(Discovery.secure_url?("http://localhost:8080/x")) - assert(Discovery.secure_url?("http://127.0.0.1/x")) - assert(Discovery.secure_url?("http://127.42.0.5/x")) - assert(Discovery.secure_url?("http://127.255.255.255/x")) - assert(Discovery.secure_url?("http://[::1]/x")) - end - - def test_secure_url_rejects_non_loopback_http - refute(Discovery.secure_url?("http://srv.example.com/mcp")) - refute(Discovery.secure_url?("http://192.168.1.1/x")) - refute(Discovery.secure_url?("http://10.0.0.1/x")) - end - - def test_secure_url_rejects_hostname_tricks_that_resemble_loopback - # Naive `start_with?("127.")` would let these slip through; IPAddr-based - # checks correctly classify them as non-loopback hostnames. - refute(Discovery.secure_url?("http://127.attacker.com/x")) - refute(Discovery.secure_url?("http://127.0.0.1.evil.com/x")) - refute(Discovery.secure_url?("http://127./x")) - # `localhost` MUST be matched exactly - `foo.localhost` is just a regular - # hostname that happens to share the suffix. - refute(Discovery.secure_url?("http://foo.localhost/x")) - end - - def test_secure_url_rejects_non_http_schemes - refute(Discovery.secure_url?("ftp://srv.example.com/mcp")) - refute(Discovery.secure_url?("file:///etc/passwd")) - refute(Discovery.secure_url?("javascript:alert(1)")) - refute(Discovery.secure_url?("")) - refute(Discovery.secure_url?(nil)) - end - - def test_secure_url_rejects_malformed_or_hostless_urls - refute(Discovery.secure_url?("https:/missing-host")) - refute(Discovery.secure_url?("https:///missing-host")) - refute(Discovery.secure_url?("https://")) - refute(Discovery.secure_url?("not a url")) - end - - def test_same_origin_accepts_matching_scheme_host_and_port - assert(Discovery.same_origin?("https://srv.example.com/.well-known/x", "https://srv.example.com/mcp")) - assert(Discovery.same_origin?("https://srv.example.com:8443/a", "https://srv.example.com:8443/b")) - assert(Discovery.same_origin?("http://localhost:9292/a", "http://localhost:9292/mcp")) - assert(Discovery.same_origin?("https://srv.example.com/a?q=1#f", "https://srv.example.com/mcp")) - end - - def test_same_origin_ignores_case_in_scheme_and_host - assert(Discovery.same_origin?("HTTPS://SRV.Example.COM/a", "https://srv.example.com/mcp")) - end - - def test_same_origin_treats_an_explicit_default_port_as_the_implicit_one - assert(Discovery.same_origin?("https://srv.example.com:443/a", "https://srv.example.com/mcp")) - assert(Discovery.same_origin?("http://srv.example.com:80/a", "http://srv.example.com/mcp")) - end - - def test_same_origin_rejects_differing_components - refute(Discovery.same_origin?("https://attacker.example.com/a", "https://srv.example.com/mcp")) - refute(Discovery.same_origin?("https://169.254.169.254/latest/", "https://srv.example.com/mcp")) - refute(Discovery.same_origin?("https://srv.example.com:8443/a", "https://srv.example.com/mcp")) - refute(Discovery.same_origin?("http://srv.example.com/a", "https://srv.example.com/mcp")) - # A subdomain is a different origin, so a hijacked challenge cannot walk - # sideways into a sibling host that shares the registrable domain. - refute(Discovery.same_origin?("https://evil.srv.example.com/a", "https://srv.example.com/mcp")) - end - - def test_same_origin_rejects_malformed_or_hostless_urls - refute(Discovery.same_origin?("not a url", "https://srv.example.com/mcp")) - refute(Discovery.same_origin?("https://srv.example.com/a", "not a url")) - refute(Discovery.same_origin?("https://", "https://srv.example.com/mcp")) - refute(Discovery.same_origin?(nil, "https://srv.example.com/mcp")) - refute(Discovery.same_origin?("/relative/path", "https://srv.example.com/mcp")) - end - - def test_private_network_host_recognizes_reserved_ipv4_ranges - assert(Discovery.private_network_host?("0.0.0.0")) - assert(Discovery.private_network_host?("10.0.0.5")) - assert(Discovery.private_network_host?("100.64.0.1")) - assert(Discovery.private_network_host?("127.0.0.1")) - # The cloud metadata address this check exists for. - assert(Discovery.private_network_host?("169.254.169.254")) - assert(Discovery.private_network_host?("172.16.0.1")) - assert(Discovery.private_network_host?("172.31.255.255")) - assert(Discovery.private_network_host?("192.168.1.1")) - end - - def test_private_network_host_recognizes_reserved_ipv6_ranges - assert(Discovery.private_network_host?("::")) - assert(Discovery.private_network_host?("::1")) - assert(Discovery.private_network_host?("[::1]")) - assert(Discovery.private_network_host?("fd00::1")) - assert(Discovery.private_network_host?("fe80::1")) - assert(Discovery.private_network_host?("[fe80::1]")) - end - - def test_private_network_host_unwraps_ipv4_mapped_ipv6 - # `::ffff:169.254.169.254` reaches the same interface as the IPv4 spelling, - # so the mapped form must not be a way around the ranges above. - assert(Discovery.private_network_host?("::ffff:169.254.169.254")) - assert(Discovery.private_network_host?("[::ffff:10.0.0.5]")) - assert(Discovery.private_network_host?("::ffff:127.0.0.1")) - refute(Discovery.private_network_host?("::ffff:93.184.216.34")) - end - - def test_private_network_host_refuses_non_canonical_ipv4_spellings - # `inet_aton` accepts forms `IPAddr` rejects, and the resolver reaches the same - # interfaces through them: `2130706433` and `127.1` are 127.0.0.1, and - # `0xa9fea9fe` is the cloud metadata address. Checking only the dotted-decimal - # spelling would refuse `169.254.169.254` and admit every alias of it. - assert(Discovery.private_network_host?("2130706433")) - assert(Discovery.private_network_host?("0x7f000001")) - assert(Discovery.private_network_host?("0xa9fea9fe")) - assert(Discovery.private_network_host?("127.1")) - assert(Discovery.private_network_host?("127.0.1")) - assert(Discovery.private_network_host?("0x7f.0.0.1")) - assert(Discovery.private_network_host?("0251.0376.0251.0376")) - end - - def test_private_network_host_refuses_numeric_spellings_whose_value_is_resolver_dependent - # `010.0.0.1` is 8.0.0.1 read as octal and 10.0.0.1 read as decimal, and platforms - # disagree on which it is. Both readings are refused rather than one being chosen, - # since the reading not taken would otherwise be a way through. - assert(Discovery.private_network_host?("010.0.0.1")) - assert(Discovery.private_network_host?("0177.0.0.1")) - - # The same applies to numeric spellings that land outside the blocked ranges, or - # nowhere at all: nothing is addressed this way on purpose. - assert(Discovery.private_network_host?("0x8080808")) - assert(Discovery.private_network_host?("256.1.1.1")) - end - - def test_private_network_host_recognizes_localhost_by_name_only - assert(Discovery.private_network_host?("localhost")) - assert(Discovery.private_network_host?("LOCALHOST")) - refute(Discovery.private_network_host?("foo.localhost")) - refute(Discovery.private_network_host?("localhost.attacker.com")) - end - - def test_private_network_host_rejects_public_addresses_and_names - refute(Discovery.private_network_host?("93.184.216.34")) - refute(Discovery.private_network_host?("8.8.8.8")) - refute(Discovery.private_network_host?("172.32.0.1")) - refute(Discovery.private_network_host?("2606:4700::1111")) - refute(Discovery.private_network_host?("srv.example.com")) - refute(Discovery.private_network_host?(nil)) - refute(Discovery.private_network_host?("")) - end - - def test_private_network_host_does_not_resolve_names - # Documents the deliberate limit of the predicate: an internal host that is - # named rather than addressed reads as public here. `same_origin?` is what - # keeps the `resource_metadata` URL from reaching one. - refute(Discovery.private_network_host?("vault.corp.internal")) - end - - def test_client_id_metadata_document_url_accepts_https_with_path - assert(Discovery.client_id_metadata_document_url?("https://app.example.com/client-metadata.json")) - assert(Discovery.client_id_metadata_document_url?("https://app.example.com/path/to/cm")) - assert(Discovery.client_id_metadata_document_url?("https://app.example.com:8443/cm")) - end - - def test_client_id_metadata_document_url_accepts_boundary_forms - # An uppercase scheme is `https` after case folding (URIs are scheme-insensitive, RFC 3986 Section 3.1). - assert(Discovery.client_id_metadata_document_url?("HTTPS://app.example.com/cm")) - - # A trailing slash and consecutive slashes are non-root, non-dot paths. - # RFC 3986 `remove_dot_segments` does not collapse them, so they remain - # stable `client_id` strings rather than aliasing another URL. - assert(Discovery.client_id_metadata_document_url?("https://app.example.com/cm/")) - assert(Discovery.client_id_metadata_document_url?("https://app.example.com//cm")) - - # The default https port is equivalent to omitting it; either form is a valid origin. - assert(Discovery.client_id_metadata_document_url?("https://app.example.com:443/cm")) - - # IPv6 literal hosts and Punycode (IDN) hosts are ordinary hosts. - assert(Discovery.client_id_metadata_document_url?("https://[2001:db8::1]/cm")) - assert(Discovery.client_id_metadata_document_url?("https://[::1]/cm")) - assert(Discovery.client_id_metadata_document_url?("https://xn--e1afmkfd.example.com/cm")) - end - - def test_client_id_metadata_document_url_rejects_non_https_schemes - refute(Discovery.client_id_metadata_document_url?("http://localhost/cm")) - refute(Discovery.client_id_metadata_document_url?("http://app.example.com/cm")) - refute(Discovery.client_id_metadata_document_url?("ftp://app.example.com/cm")) - refute(Discovery.client_id_metadata_document_url?("file:///cm")) - end - - def test_client_id_metadata_document_url_rejects_root_and_empty_path - refute(Discovery.client_id_metadata_document_url?("https://app.example.com")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/")) - end - - def test_client_id_metadata_document_url_rejects_fragment_query_userinfo - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/cm#frag")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/cm?x=1")) - refute(Discovery.client_id_metadata_document_url?("https://user:pass@app.example.com/cm")) - refute(Discovery.client_id_metadata_document_url?("https://user@app.example.com/cm")) - end - - def test_client_id_metadata_document_url_rejects_dot_segments - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/./cm")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/a/../cm")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/cm/.")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/cm/..")) - # Percent-encoded `.` would otherwise let `%2E` and `.` produce - # different `client_id` values for the same document. - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/%2E/cm")) - refute(Discovery.client_id_metadata_document_url?("https://app.example.com/%2e/cm")) - end - - def test_client_id_metadata_document_url_rejects_nil_or_empty_or_malformed - refute(Discovery.client_id_metadata_document_url?(nil)) - refute(Discovery.client_id_metadata_document_url?("")) - refute(Discovery.client_id_metadata_document_url?("not a url")) - refute(Discovery.client_id_metadata_document_url?("https://")) - end - - def test_resource_covers_blocks_percent_encoded_dot_segment_bypass - server = Discovery.canonicalize_url("https://srv.example.com/api/%2e%2e/mcp") - prm = Discovery.canonicalize_url("https://srv.example.com/api") - - refute( - Discovery.resource_covers?(prm: prm, server: server), - "PRM `resource=/api` must not cover `/api/%2e%2e/mcp` after canonicalization", - ) - end - - def test_resource_covers_blocks_cross_tenant_query_bypass - # An attacker-controlled PRM that advertises a different tenant's - # resource URI MUST NOT be treated as covering the server URL. If it - # were, the client would mint a token for `tenant=evil` while - # actually talking to `tenant=victim`, defeating audience binding. - server = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=victim") - prm_evil = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=evil") - - refute( - Discovery.resource_covers?(prm: prm_evil, server: server), - "PRM `resource=?tenant=evil` must not cover server `?tenant=victim`", - ) - end - - def test_resource_covers_allows_matching_query - server = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=victim") - prm = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=victim") - - assert(Discovery.resource_covers?(prm: prm, server: server)) - end - - def test_resource_covers_allows_prm_without_query_to_cover_server_with_query - # A query-less PRM acts as a generic identifier over the origin + - # path prefix and is allowed to cover server URLs that scope by query. - server = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=1") - prm = Discovery.canonicalize_url("https://srv.example.com/mcp") - - assert(Discovery.resource_covers?(prm: prm, server: server)) - end - - def test_resource_covers_blocks_prm_with_query_when_server_has_none - # PRM that names a specific tenant cannot cover an unscoped server - # URL; otherwise a hijacked PRM could re-bind the token to a tenant - # the user did not select. - server = Discovery.canonicalize_url("https://srv.example.com/mcp") - prm = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=evil") - - refute(Discovery.resource_covers?(prm: prm, server: server)) - end - - def test_resource_covers_does_not_treat_empty_query_as_wildcard - # `https://srv.example.com/mcp?` parses with `URI#query == ""`, which - # is distinct from "no query at all" (`URI#query == nil`). A naive - # `prm_query.nil? || prm_query.empty?` would let an attacker-supplied - # PRM with a trailing `?` slip past the cross-tenant audience check. - server = Discovery.canonicalize_url("https://srv.example.com/mcp?tenant=victim") - prm_empty_query = "https://srv.example.com/mcp?" - - refute( - Discovery.resource_covers?(prm: prm_empty_query, server: server), - "PRM with a literal empty query (`?`) must not act as a wildcard cover", - ) - end - - def test_resource_covers_returns_true_for_same_origin_prefix - assert(Discovery.resource_covers?( - prm: "https://srv.example.com", - server: "https://srv.example.com/mcp", - )) - assert(Discovery.resource_covers?( - prm: "https://srv.example.com/mcp", - server: "https://srv.example.com/mcp", - )) - assert(Discovery.resource_covers?( - prm: "https://srv.example.com/api", - server: "https://srv.example.com/api/v2/mcp", - )) - end - - def test_resource_covers_returns_false_for_different_origin_or_path_mismatch - refute(Discovery.resource_covers?( - prm: "https://evil.example.com/mcp", - server: "https://srv.example.com/mcp", - )) - refute(Discovery.resource_covers?( - prm: "https://srv.example.com:8443/mcp", - server: "https://srv.example.com/mcp", - )) - # Path "api" must not be considered a prefix of "/apiv2". - refute(Discovery.resource_covers?( - prm: "https://srv.example.com/api", - server: "https://srv.example.com/apiv2", - )) - end - end - end - end -end diff --git a/test/mcp/client/oauth/flow_test.rb b/test/mcp/client/oauth/flow_test.rb deleted file mode 100644 index c13b49b..0000000 --- a/test/mcp/client/oauth/flow_test.rb +++ /dev/null @@ -1,4453 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "base64" -require "json" -require "webmock/minitest" -require "faraday" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class FlowTest < Minitest::Test - def setup - WebMock.enable! - @server_url = "https://srv.example.com/mcp" - @prm_url = "https://srv.example.com/.well-known/oauth-protected-resource/mcp" - @auth_base = "https://auth.example.com" - @as_metadata_url = "#{@auth_base}/.well-known/oauth-authorization-server" - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client", client_name: "ruby-sdk-test"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return do |req| - form = URI.decode_www_form(req.body).to_h - { - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - access_token: "test-token-from-flow", - token_type: "Bearer", - expires_in: 3600, - grant_type_received: form["grant_type"], - code_verifier_received: form["code_verifier"], - ), - } - end - end - - def teardown - WebMock.reset! - end - - # A plain authorization-code provider for the destination-check tests. - # They all expect to fail before any redirect happens, so the handlers stay inert; - # a test that reached them would be asserting the wrong thing. - def ssrf_test_provider - Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - end - - def client_credentials_provider(token_endpoint_auth_method: "client_secret_basic", token_request_params: nil, http_client_customizer: nil) - ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - token_endpoint_auth_method: token_endpoint_auth_method, - token_request_params: token_request_params, - http_client_customizer: http_client_customizer, - ) - end - - # An authorization-code provider that drives the code exchange and refresh with the given parameters. - def provider_with_token_request_params(params, redirect_handler: ->(_url) {}, callback_handler: -> { [nil, nil] }) - Provider.new(**authorization_code_provider_arguments(redirect_handler, callback_handler), token_request_params: params) - end - - # Overriding the reader bypasses the constructor's validation, leaving the flow's own check to be exercised. - def provider_returning_token_request_params(params, redirect_handler: ->(_url) {}, callback_handler: -> { [nil, nil] }) - provider_class = Class.new(Provider) do - define_method(:token_request_params) { params } - end - - provider_class.new(**authorization_code_provider_arguments(redirect_handler, callback_handler)) - end - - def authorization_code_provider_arguments(redirect_handler, callback_handler) - { - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: redirect_handler, - callback_handler: callback_handler, - } - end - - # See `provider_returning_token_request_params`. - def client_credentials_provider_returning(token_request_params:) - provider_class = Class.new(ClientCredentialsProvider) do - define_method(:token_request_params) { token_request_params } - end - - provider_class.new(client_id: "cc-client", client_secret: "cc-secret") - end - - # `OpenSSL::PKey::EC.generate` only exists from the openssl gem 2.2 (Ruby 3.0); - # fall back to the pre-3.0 API on older Rubies. - def generate_es256_key - if OpenSSL::PKey::EC.respond_to?(:generate) - OpenSSL::PKey::EC.generate("prime256v1") - else - OpenSSL::PKey::EC.new("prime256v1").tap(&:generate_key) - end - end - - # Records `[method, url]` for every request that passes through, standing in for the tracing middleware - # an application adds through `http_client_customizer`. - class RecordingMiddleware - def initialize(app, log) - @app = app - @log = log - end - - def call(env) - @log << [env.method, env.url.to_s] - @app.call(env) - end - end - - # Sends the request for `from` to `to` instead, the shape redirect-following middleware leaves behind: - # the flow asked for one URL and the adapter is handed another. - class URLRewritingMiddleware - def initialize(app, from:, to:) - @app = app - @from = from - @to = to - end - - def call(env) - env.url = URI(@to) if env.url.to_s == @from - @app.call(env) - end - end - - # Replaces the per-request context the way instrumentation middleware may; the guard must not depend on it. - class ContextReplacingMiddleware - def initialize(app) - @app = app - end - - def call(env) - env.request.context = { tag: "instrumented" } - @app.call(env) - end - end - - # Hands the next middleware an environment rebuilt from Faraday's own members only, dropping whatever - # an earlier middleware recorded on the original. - class EnvRebuildingMiddleware - def initialize(app) - @app = app - end - - def call(env) - @app.call(Faraday::Env.from(env.to_h)) - end - end - - # Follows a `3xx` the way `faraday-follow_redirects` does: duplicates the environment, points it at the `Location`, - # and re-enters the stack from its own position. - class RedirectFollowingMiddleware - def initialize(app) - @app = app - end - - def call(env) - response = @app.call(env) - location = response.headers["Location"] - return response unless location && (300..399).cover?(response.status) - - redirected = env.dup - redirected.url = URI(location) - redirected.response = nil - @app.call(redirected) - end - end - - # Replaces the request options wholesale, the way middleware that resets timeouts or contexts might. - class RequestOptionsReplacingMiddleware - def initialize(app) - @app = app - end - - def call(env) - env.request = Faraday::RequestOptions.new - @app.call(env) - end - end - - # Re-enters the stack once with the same environment after a `5xx`, the way retry middleware does. - class RetryingMiddleware - def initialize(app) - @app = app - end - - def call(env) - response = @app.call(env) - return response unless response.status >= 500 - - env.response = nil - @app.call(env) - end - end - - # Records the application's `trace_id` from the per-request context, as a tracing middleware would. - class ContextRecordingMiddleware - def initialize(app, log) - @app = app - @log = log - end - - def call(env) - @log << env.request.context&.dig(:trace_id) - @app.call(env) - end - end - - # Runs the full authorization flow and returns the `scope` query parameter - # sent on the authorization request. The caller stubs the AS metadata; - # this helper supplies a provider whose `grant_types` and optional pre-set - # `scope` drive the SEP-2207 offline_access decision. - def capture_authorization_scope(grant_types:, provider_scope: nil) - captured_scope = nil - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: grant_types, - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - query = URI.decode_www_form(url.query).to_h - captured_scope = query["scope"] - state_holder[:state] = query.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - scope: provider_scope, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - captured_scope - end - - def test_run_uses_client_credentials_grant_for_client_credentials_provider - provider = client_credentials_provider - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal("test-token-from-flow", provider.access_token) - # No authorization-code machinery: /authorize is never contacted - # (no stub exists for it, so a request would raise), and DCR is not - # run because credentials are pre-registered. - assert_not_requested(:post, "#{@auth_base}/register") - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - expected_basic = "Basic " + Base64.strict_encode64("cc-client:cc-secret") - form["grant_type"] == "client_credentials" && - !form.key?("code") && - !form.key?("code_verifier") && - req.headers["Authorization"] == expected_basic - end - end - - def test_run_sends_every_authorization_server_request_through_the_provider_customizer - log = [] - provider = client_credentials_provider(http_client_customizer: ->(faraday) { faraday.use(RecordingMiddleware, log) }) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal([[:get, @prm_url], [:get, @as_metadata_url], [:post, "#{@auth_base}/token"]], log) - - # The SDK's defaults are applied before the customizer runs. - assert_requested(:get, @prm_url, headers: { "Accept" => "application/json" }) - end - - def test_run_refuses_a_customized_connection_that_sends_a_request_off_the_origin - stub_request(:get, "https://other.example.com/prm.json").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { faraday.use(URLRewritingMiddleware, from: @prm_url, to: "https://other.example.com/prm.json") }, - ) - - error = assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_equal(<<~MESSAGE, error.message) - Request to \"#{@prm_url}\" would be sent to \"https://other.example.com/prm.json\", on a different origin; \ - middleware that follows redirects or rewrites URLs is refused. - MESSAGE - - # The guard sits before the adapter, so the request never leaves. - assert_not_requested(:get, "https://other.example.com/prm.json") - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_keeps_a_same_origin_rewrite - moved_url = "https://srv.example.com/prm-moved.json" - stub_request(:get, moved_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { faraday.use(URLRewritingMiddleware, from: @prm_url, to: moved_url) }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:get, moved_url) - end - - def test_run_refuses_a_rewritten_request_even_when_middleware_replaces_the_request_context - stub_request(:get, "https://other.example.com/prm.json").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { - faraday.use(ContextReplacingMiddleware) - faraday.use(URLRewritingMiddleware, from: @prm_url, to: "https://other.example.com/prm.json") - }, - ) - - assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:get, "https://other.example.com/prm.json") - end - - def test_run_refuses_a_redirect_off_the_origin_followed_by_middleware_placed_ahead_of_the_stamp - # `builder.insert(0, ...)` is where middleware that wants to be outermost puts itself, so a follower can - # land ahead of the SDK's stamp and re-enter the stack; the record of the first URL must survive that. - stub_request(:get, @prm_url).to_return(status: 302, headers: { "Location" => "https://other.example.com/prm.json" }) - stub_request(:get, "https://other.example.com/prm.json").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { faraday.builder.insert(0, RedirectFollowingMiddleware) }, - ) - - error = assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/would be sent to "https:\/\/other\.example\.com\/prm\.json", on a different origin/, error.message) - assert_not_requested(:get, "https://other.example.com/prm.json") - end - - def test_run_keeps_a_same_origin_redirect_followed_by_middleware_placed_ahead_of_the_stamp - moved_url = "https://srv.example.com/prm-moved.json" - stub_request(:get, @prm_url).to_return(status: 302, headers: { "Location" => moved_url }) - stub_request(:get, moved_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { faraday.builder.insert(0, RedirectFollowingMiddleware) }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:get, moved_url) - end - - def test_run_refuses_a_request_whose_environment_was_rebuilt - provider = client_credentials_provider(http_client_customizer: ->(faraday) { faraday.use(EnvRebuildingMiddleware) }) - - error = assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_equal(<<~MESSAGE, error.message) - Request to \"#{@prm_url}\" carries no record of the URL the flow asked for; \ - middleware that rebuilds the request environment is refused. - MESSAGE - assert_not_requested(:get, @prm_url) - end - - def test_run_refuses_a_rewritten_token_request - stub_request(:post, "https://other.example.com/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "stolen", token_type: "Bearer"), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { - faraday.use(URLRewritingMiddleware, from: "#{@auth_base}/token", to: "https://other.example.com/token") - }, - ) - - assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:post, "https://other.example.com/token") - assert_not_requested(:post, "#{@auth_base}/token") - assert_nil(provider.access_token) - end - - def test_run_keeps_the_application_request_context_for_every_request - trace_ids = [] - - result = run_authorization_flow( - http_client_customizer: ->(faraday) { - faraday.options.context = { trace_id: "incident-123" } - faraday.use(ContextRecordingMiddleware, trace_ids) - }, - ) - - assert_equal(:authorized, result) - # Protected Resource Metadata and authorization server metadata (GET), registration (JSON POST), - # and the token exchange (form POST) all carry it. - assert_equal(["incident-123"] * 4, trace_ids) - end - - def test_run_keeps_the_application_request_context_on_a_factory_connection - trace_ids = [] - factory = -> { - Faraday.new do |faraday| - faraday.options.context = { trace_id: "incident-123" } - faraday.use(ContextRecordingMiddleware, trace_ids) - end - } - - result = Flow.new(provider: client_credentials_provider, http_client_factory: factory).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal(["incident-123"] * 3, trace_ids) - end - - def test_run_refuses_a_rewritten_request_even_when_middleware_replaces_the_request_options - stub_request(:get, "https://other.example.com/prm.json").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider( - http_client_customizer: ->(faraday) { - faraday.use(RequestOptionsReplacingMiddleware) - faraday.use(URLRewritingMiddleware, from: @prm_url, to: "https://other.example.com/prm.json") - }, - ) - - error = assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - # The mismatch, not a lost record: replacing the options must leave the record in place. - assert_match(/would be sent to "https:\/\/other\.example\.com\/prm\.json", on a different origin/, error.message) - assert_not_requested(:get, "https://other.example.com/prm.json") - end - - def test_run_refuses_a_redirect_off_the_origin_followed_by_middleware_placed_after_the_stamp - stub_request(:get, @prm_url).to_return(status: 302, headers: { "Location" => "https://other.example.com/prm.json" }) - stub_request(:get, "https://other.example.com/prm.json").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider(http_client_customizer: ->(faraday) { faraday.use(RedirectFollowingMiddleware) }) - - error = assert_raises(Flow::DestinationMismatchError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - # The mismatch, not a lost record: the duplicate the follower re-enters with shares the record. - assert_match(/would be sent to "https:\/\/other\.example\.com\/prm\.json", on a different origin/, error.message) - assert_not_requested(:get, "https://other.example.com/prm.json") - end - - def test_run_keeps_a_same_origin_redirect_followed_by_middleware_placed_after_the_stamp - moved_url = "https://srv.example.com/prm-moved.json" - stub_request(:get, @prm_url).to_return(status: 302, headers: { "Location" => moved_url }) - stub_request(:get, moved_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - provider = client_credentials_provider(http_client_customizer: ->(faraday) { faraday.use(RedirectFollowingMiddleware) }) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:get, moved_url) - end - - def test_run_keeps_a_retry_by_middleware_placed_ahead_of_the_stamp - # The same environment re-enters the stack with the same URL, so the first record still matches. - stub_request(:get, @prm_url).to_return( - { status: 503 }, - { - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - }, - ) - provider = client_credentials_provider(http_client_customizer: ->(faraday) { faraday.builder.insert(0, RetryingMiddleware) }) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:get, @prm_url, times: 2) - end - - def test_build_http_client_records_each_request_on_its_own - # A caller using the SDK-built connection directly may address different origins from one request - # to the next; each request gets its own record. - stub_request(:get, "https://a.example.com/one").to_return(status: 200, body: "one") - stub_request(:get, "https://b.example.com/two").to_return(status: 200, body: "two") - connection = Flow.build_http_client - - assert_equal("one", connection.get("https://a.example.com/one").body) - assert_equal("two", connection.get("https://b.example.com/two").body) - end - - def test_run_prefers_an_explicit_http_client_factory_over_the_customizer - provider = client_credentials_provider(http_client_customizer: ->(_faraday) { raise "the customizer must not run" }) - - result = Flow.new(provider: provider, http_client_factory: -> { Faraday.new }).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - end - - def test_run_client_credentials_with_client_secret_post_sends_credentials_in_body - # `client_secret_post` puts the credentials in the form body rather - # than an HTTP Basic header (RFC 6749 Section 2.3.1). - provider = client_credentials_provider(token_endpoint_auth_method: "client_secret_post") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - form["grant_type"] == "client_credentials" && - form["client_id"] == "cc-client" && - form["client_secret"] == "cc-secret" && - req.headers["Authorization"].nil? - end - end - - def test_run_client_credentials_with_client_secret_basic_omits_client_id_from_body - # Explicit Basic authentication must keep both credentials in the header - # to avoid servers treating body credentials as a second auth method. - provider = client_credentials_provider(token_endpoint_auth_method: "client_secret_basic") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - req.headers["Authorization"] == "Basic " + Base64.strict_encode64("cc-client:cc-secret") && - !form.key?("client_id") && - !form.key?("client_secret") - end - end - - def test_run_client_credentials_raises_clean_error_when_client_information_missing - # The constructor always stores credentials, but if a custom storage loses them - # the grant must fail with a domain error rather than a `NoMethodError` from - # the authorization-code registration helper. - provider = client_credentials_provider - provider.storage.save_client_information(nil) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - assert_match(/client_credentials grant/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_client_credentials_succeeds_with_matching_stored_issuer - provider = client_credentials_provider - provider.storage.save_client_information( - provider.storage.client_information.merge("issuer" => @auth_base), - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - end - - def test_run_client_credentials_raises_for_mismatched_stored_issuer - # Per SEP-2352, static machine-to-machine credentials bound to another authorization server must surface - # an error instead of being replayed; re-registration is not an option for pre-registered credentials. - provider = client_credentials_provider - provider.storage.save_client_information( - provider.storage.client_information.merge("issuer" => "https://old-as.example.com"), - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/bound to a different authorization server/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_client_credentials_requests_scope_from_prm_scopes_supported - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - scopes_supported: ["mcp:read", "mcp:write"], - ), - ) - - provider = client_credentials_provider - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["scope"] == "mcp:read mcp:write" - end - end - - def test_run_client_credentials_with_private_key_jwt_sends_signed_assertion - # SEP-1046 / RFC 7523 Section 2.2: the token request authenticates - # with a signed JWT assertion; `client_id` and any shared secret are - # absent from the body, and the assertion's audience is the AS issuer. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - token_endpoint: "#{@auth_base}/token", - grant_types_supported: ["client_credentials"], - token_endpoint_auth_methods_supported: ["private_key_jwt"], - token_endpoint_auth_signing_alg_values_supported: ["ES256"], - ), - ) - - provider = ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - private_key: generate_es256_key, - signing_algorithm: "ES256", - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal("test-token-from-flow", provider.access_token) - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - payload_segment = form["client_assertion"].to_s.split(".")[1].to_s - claims = JSON.parse(Base64.urlsafe_decode64(payload_segment + "=" * (-payload_segment.length % 4))) - - form["grant_type"] == "client_credentials" && - form["client_assertion_type"] == "urn:ietf:params:oauth:client-assertion-type:jwt-bearer" && - !form.key?("client_id") && - !form.key?("client_secret") && - req.headers["Authorization"].nil? && - claims["iss"] == "cc-client" && - claims["sub"] == "cc-client" && - claims["aud"] == @auth_base && - form["resource"] == "https://srv.example.com/mcp" - end - end - - def test_run_client_credentials_sends_token_request_params_with_client_secret_basic - provider = client_credentials_provider(token_request_params: { "audience" => "https://api.example.com" }) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "client_credentials" && - form["resource"] == "https://srv.example.com/mcp" && - form["audience"] == "https://api.example.com" && - !form.key?("client_id") && - req.headers["Authorization"] == "Basic " + Base64.strict_encode64("cc-client:cc-secret") - end - end - - def test_run_client_credentials_sends_token_request_params_returned_by_a_provider_method - provider = client_credentials_provider_returning(token_request_params: { "audience" => "https://api.example.com" }) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["audience"] == "https://api.example.com" - end - end - - def test_run_client_credentials_sends_the_same_request_for_empty_token_request_params - provider = client_credentials_provider(token_request_params: {}) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).map(&:first) == ["grant_type", "resource"] - end - end - - def test_run_client_credentials_sends_token_request_params_with_client_secret_post - provider = client_credentials_provider( - token_endpoint_auth_method: "client_secret_post", - token_request_params: { "audience" => "https://api.example.com" }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["audience"] == "https://api.example.com" && - form["client_id"] == "cc-client" && - form["client_secret"] == "cc-secret" - end - end - - def test_run_client_credentials_sends_token_request_params_with_private_key_jwt - provider = ClientCredentialsProvider.new( - client_id: "cc-client", - token_endpoint_auth_method: "private_key_jwt", - private_key: generate_es256_key, - signing_algorithm: "ES256", - token_request_params: { "audience" => "https://api.example.com" }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["audience"] == "https://api.example.com" && - form["client_assertion_type"] == "urn:ietf:params:oauth:client-assertion-type:jwt-bearer" && - !form["client_assertion"].to_s.empty? - end - end - - def test_run_sends_token_request_params_on_the_authorization_code_exchange - state_value = nil - provider = provider_with_token_request_params( - { "audience" => "https://api.example.com" }, - redirect_handler: ->(url) { state_value = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_value] }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "authorization_code" && - form["code"] == "test-auth-code" && - form["audience"] == "https://api.example.com" - end - end - - def test_refresh_sends_token_request_params - provider = provider_with_token_request_params({ "audience" => "https://api.example.com" }) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - result = Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:refreshed, result) - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "refresh_token" && - form["refresh_token"] == "saved-rt" && - form["audience"] == "https://api.example.com" - end - end - - def test_run_sends_token_request_params_on_the_jwt_bearer_grant - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag-assertion" }, - token_request_params: { "audience" => "https://api.example.com" }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "urn:ietf:params:oauth:grant-type:jwt-bearer" && - form["assertion"] == "id-jag-assertion" && - form["audience"] == "https://api.example.com" - end - end - - def test_run_refuses_token_request_params_that_name_a_reserved_parameter - provider = client_credentials_provider_returning(token_request_params: { "grant_type" => "password" }) - - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/"grant_type"/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_refuses_token_request_params_that_are_not_a_hash_of_strings - shapes = ["audience=x", { audience: "x" }, { "audience" => 1 }, { "audience" => nil }, { "audience" => "x" }.compare_by_identity] - shapes.each do |params| - provider = client_credentials_provider_returning(token_request_params: params) - - assert_raises(Flow::InvalidTokenRequestParamsError, "should refuse #{params.inspect}") do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - end - - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_refuses_token_request_params_that_name_a_reserved_parameter - # Not an `AuthorizationError`: the transport treats a failed refresh as a reason - # to run the interactive flow, which would fail the same way afterwards. - provider = provider_returning_token_request_params({ "refresh_token" => "other" }) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/"refresh_token"/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_refuses_token_request_params_on_the_authorization_code_exchange - state_value = nil - provider = provider_returning_token_request_params( - { "code" => "other" }, - redirect_handler: ->(url) { state_value = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_value] }, - ) - - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/"code"/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_uses_jwt_bearer_grant_for_cross_app_access_provider - # SEP-990: the ID-JAG assertion (obtained out of band, typically via IdP token exchange) is presented at - # the token endpoint with client_secret_basic; no PKCE, redirect, or DCR is involved. - received = nil - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(audience:, resource:) { - received = { audience: audience, resource: resource } - "id-jag-assertion" - }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal("test-token-from-flow", provider.access_token) - # The assertion audience is the validated AS issuer; the resource is the canonical MCP server URL. - assert_equal({ audience: @auth_base, resource: "https://srv.example.com/mcp" }, received) - assert_not_requested(:post, "#{@auth_base}/register") - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - expected_basic = "Basic " + Base64.strict_encode64("xaa-client:xaa-secret") - form["grant_type"] == "urn:ietf:params:oauth:grant-type:jwt-bearer" && - form["assertion"] == "id-jag-assertion" && - form["resource"] == "https://srv.example.com/mcp" && - !form.key?("code") && - !form.key?("code_verifier") && - req.headers["Authorization"] == expected_basic - end - end - - def test_run_jwt_bearer_raises_when_assertion_provider_returns_nothing - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(audience:, resource:) {}, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/returned no ID-JAG/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_uses_the_stored_credentials_of_a_cross_app_access_provider - # RFC 7521 Section 4.1 makes a refresh token unusual for an assertion grant, not forbidden; - # when the authorization server issued one, it is exchanged with the stored client secret - # and no new ID-JAG assertion is minted. - assertion_calls = 0 - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { - assertion_calls += 1 - "id-jag-assertion" - }, - ) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt", "issuer" => @auth_base) - - result = Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:refreshed, result) - assert_equal("test-token-from-flow", provider.access_token) - assert_equal(@auth_base, provider.tokens["issuer"]) - assert_equal(0, assertion_calls) - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "refresh_token" && - form["refresh_token"] == "saved-rt" && - !form.key?("assertion") && - req.headers["Authorization"] == "Basic " + Base64.strict_encode64("xaa-client:xaa-secret") - end - end - - def test_refresh_uses_the_stored_credentials_of_a_client_credentials_provider - # RFC 6749 Section 4.4.3 says a refresh token SHOULD NOT be issued for this grant, - # so one in storage is unusual, but it must be exchanged rather than crash the refresh. - provider = client_credentials_provider - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt", "issuer" => @auth_base) - - result = Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:refreshed, result) - assert_equal(@auth_base, provider.tokens["issuer"]) - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "refresh_token" && - form["refresh_token"] == "saved-rt" && - req.headers["Authorization"] == "Basic " + Base64.strict_encode64("cc-client:cc-secret") - end - end - - def test_refresh_refuses_an_authorization_server_that_did_not_issue_a_cross_app_access_token - # The token-level issuer binding is what protects these providers: their stored `client_information` carries no `issuer`, - # so `ensure_refreshable_client_information!` has nothing to compare. - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag-assertion" }, - ) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt", "issuer" => "https://old-as.example.com") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issued by a different authorization server/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_refresh_refuses_tokens_without_a_recorded_issuer_for_the_client_credentials_and_jwt_bearer_providers - # These providers had no refresh before their tokens recorded the issuer, so nothing older needs - # tolerating; without the record a refresh would go to whatever server discovery names, unasked. - cross_app = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag-assertion" }, - ) - [cross_app, client_credentials_provider].each do |provider| - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::AuthorizationError, "should refuse #{provider.class}") do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/record no issuer/, error.message) - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - assert_not_requested(:get, @prm_url) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_raises_cleanly_for_a_provider_with_neither_client_information_nor_a_cimd_url - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { "id-jag-assertion" }, - ) - provider.storage.save_client_information(nil) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt", "issuer" => @auth_base) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/no client_information/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_registers_through_dcr_for_a_provider_without_a_cimd_url_reader - # Registration reads the CIMD URL through the same duck-typed helper as refresh, - # so a provider that lacks the reader goes to Dynamic Client Registration. - provider_class = Class.new(Provider) { undef_method :client_id_metadata_document_url } - state_value = nil - provider = provider_class.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { state_value = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_value] }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_requested(:post, "#{@auth_base}/register") - end - - def test_run_uses_authorization_code_grant_for_default_provider - # A standard `Provider` declares `authorization_flow == :authorization_code`, - # so `Flow` runs the interactive grant regardless of what `client_metadata[:grant_types]` happens to list. - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code", "client_credentials"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["grant_type"] == "authorization_code" - end - end - - # Runs the full authorization flow with a minimal provider so tests can assert on - # the Dynamic Client Registration request body. The default loopback redirect URI - # exercises SEP-837's `"native"` inference; passing an HTTPS `redirect_uri` exercises - # the `"web"` inference. - def run_authorization_flow(redirect_uri: "http://localhost:0/callback", client_metadata_extra: {}, http_client_customizer: nil) - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: [redirect_uri], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }.merge(client_metadata_extra), - redirect_uri: redirect_uri, - redirect_handler: ->(url) { state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - http_client_customizer: http_client_customizer, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - # Runs the authorization-code flow with an `authorization_request_validator` that records what it - # was handed and answers `approve`. - private def run_flow_with_validator(approve:, recorder: []) - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - recorder << :redirected - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - authorization_request_validator: ->(request) { - recorder << request - approve - }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - def test_run_hands_the_authorization_server_and_scopes_to_the_validator - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: @server_url, - authorization_servers: [@auth_base], - scopes_supported: ["Mail.Read", "Files.ReadWrite.All"], - ), - ) - - recorder = [] - run_flow_with_validator(approve: true, recorder: recorder) - - request = recorder.first - - assert_equal(@auth_base, request.authorization_server) - assert_equal(["Mail.Read", "Files.ReadWrite.All"], request.scopes) - assert_equal(@server_url, request.server_url) - assert_equal("https://srv.example.com/mcp", request.resource) - end - - def test_run_refuses_the_flow_and_registers_nothing_when_the_validator_declines - recorder = [] - - error = assert_raises(Flow::AuthorizationRefusedError) do - run_flow_with_validator(approve: false, recorder: recorder) - end - - assert_match(/refused by `authorization_request_validator`/, error.message) - - # Refused before registration, so nothing of this client is left at the authorization server - # the host just rejected, and no browser was opened. - assert_not_requested(:post, "#{@auth_base}/register") - refute_includes(recorder, :redirected) - end - - def test_run_client_credentials_consults_the_validator - provider = ClientCredentialsProvider.new( - client_id: "cc-client", - client_secret: "cc-secret", - authorization_request_validator: ->(_request) { false }, - ) - - error = assert_raises(Flow::AuthorizationRefusedError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/refused by `authorization_request_validator`/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_jwt_bearer_consults_the_validator - minted = false - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(audience:, resource:) { - minted = true - "id-jag-assertion" - }, - authorization_request_validator: ->(_request) { false }, - ) - - error = assert_raises(Flow::AuthorizationRefusedError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/refused by `authorization_request_validator`/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - - # Refused before the identity provider was asked for an assertion carrying this authorization server as its audience. - refute(minted, "the ID-JAG assertion must not be minted for a refused authorization server") - end - - def test_run_registers_native_application_type_for_loopback_redirect_uri - run_authorization_flow - - assert_requested(:post, "#{@auth_base}/register") do |req| - JSON.parse(req.body)["application_type"] == "native" - end - end - - def test_run_registers_web_application_type_for_https_redirect_uri - run_authorization_flow(redirect_uri: "https://app.example.com/callback") - - assert_requested(:post, "#{@auth_base}/register") do |req| - JSON.parse(req.body)["application_type"] == "web" - end - end - - def test_run_does_not_override_explicit_application_type - run_authorization_flow(client_metadata_extra: { application_type: "web" }) - - assert_requested(:post, "#{@auth_base}/register") do |req| - JSON.parse(req.body)["application_type"] == "web" - end - end - - def test_run_does_not_override_explicit_string_keyed_application_type - run_authorization_flow( - redirect_uri: "https://app.example.com/callback", - client_metadata_extra: { "application_type" => "native" }, - ) - - assert_requested(:post, "#{@auth_base}/register") do |req| - JSON.parse(req.body)["application_type"] == "native" - end - end - - def test_run_completes_full_authorization_flow - captured_authorization_url = nil - state_value = nil - - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - captured_authorization_url = url - state_value = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_value] }, - ) - - flow = Flow.new(provider: provider) - result = flow.run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal("test-token-from-flow", provider.access_token) - - query = URI.decode_www_form(captured_authorization_url.query).to_h - assert_equal("code", query["response_type"]) - assert_equal("test-client", query["client_id"]) - assert_equal("S256", query["code_challenge_method"]) - assert_equal("http://localhost:0/callback", query["redirect_uri"]) - assert_equal("https://srv.example.com/mcp", query["resource"]) - - assert_requested(:get, @prm_url) - assert_requested(:post, "#{@auth_base}/register") - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - form["grant_type"] == "authorization_code" && - form["code"] == "test-auth-code" && - !form["code_verifier"].to_s.empty? && - form["resource"] == "https://srv.example.com/mcp" - end - end - - def test_run_requests_offline_access_when_advertised_and_refresh_token_grant_declared - # SEP-2207: a client that declares the `refresh_token` grant type requests `offline_access` - # when the AS advertises it, so it can obtain a refresh token. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic", "offline_access"], - ), - ) - - captured = capture_authorization_scope(grant_types: ["authorization_code", "refresh_token"]) - - assert_includes(captured.split, "offline_access") - end - - def test_run_does_not_request_offline_access_when_refresh_token_grant_not_declared - # The AS advertises offline_access, but the client did not opt into refresh tokens, - # so the scope is not requested. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic", "offline_access"], - ), - ) - - captured = capture_authorization_scope(grant_types: ["authorization_code"]) - - refute_includes(captured.to_s.split, "offline_access") - end - - def test_run_does_not_request_offline_access_when_server_does_not_advertise_it - # SEP-2207 forbids requesting offline_access when the AS does not list it, - # even if the client declared the refresh_token grant type. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic", "mcp:read"], - ), - ) - - captured = capture_authorization_scope(grant_types: ["authorization_code", "refresh_token"]) - - refute_includes(captured.to_s.split, "offline_access") - end - - def test_run_strips_offline_access_from_provider_scope_when_server_does_not_advertise_it - # SDK policy: even when `offline_access` reaches the resolved scope from a provider-supplied scope - # (or a challenge / PRM scope), do not propagate it to the AS when the AS does not advertise the scope. - # SEP-2207 itself only says clients should not request unsupported scopes; this strip is the SDK's - # defensive layer against misbehaving resource servers and misconfigured PRMs that surface `offline_access` - # even though the AS has not opted in. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic"], - ), - ) - - captured = capture_authorization_scope( - grant_types: ["authorization_code", "refresh_token"], - provider_scope: "mcp:basic offline_access", - ) - - refute_includes(captured.to_s.split, "offline_access") - assert_includes(captured.to_s.split, "mcp:basic") - end - - def test_run_strips_sole_offline_access_scope_when_server_does_not_advertise_it - # When stripping leaves an empty scope, no `scope` parameter is sent. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic"], - ), - ) - - captured = capture_authorization_scope( - grant_types: ["authorization_code", "refresh_token"], - provider_scope: "offline_access", - ) - - assert_nil(captured) - end - - def test_run_does_not_duplicate_offline_access_already_in_scope - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - scopes_supported: ["mcp:basic", "offline_access"], - ), - ) - - captured = capture_authorization_scope( - grant_types: ["authorization_code", "refresh_token"], - provider_scope: "mcp:basic offline_access", - ) - - assert_equal(1, captured.split.count("offline_access")) - end - - def test_run_raises_on_state_mismatch - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "wrong-state"] }, - ) - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - end - - def test_run_raises_when_pkce_unsupported - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["plain"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/S256/, error.message) - end - - def test_run_raises_when_authorization_endpoint_is_missing - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - # NB: no `authorization_endpoint`. - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["S256"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/authorization_endpoint/i, error.message) - end - - def test_run_raises_when_authorization_endpoint_is_malformed_uri - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "ht!tp:bad uri", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["S256"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/authorization_endpoint/i, error.message) - end - - def test_run_raises_when_prm_resource_is_malformed_uri - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "ht!tp:bad uri", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/PRM `resource`|not a valid URI/i, error.message) - end - - def test_run_falls_back_to_legacy_discovery_when_prm_is_not_a_json_object - # Valid JSON but the wrong shape counts as nothing usable being published, so it selects the legacy 2025-03-26 path - # (matching the TypeScript and Python SDKs); here the legacy path also dead-ends, surfacing a domain error rather than - # a raw `TypeError` from indexing the array. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: "[]", - ) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource/mcp").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/openid-configuration").to_return(status: 404) - stub_request(:post, "https://srv.example.com/register").to_return(status: 404) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/Dynamic client registration failed/i, error.message) - assert_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - end - - def test_run_surfaces_a_network_error_during_prm_discovery_instead_of_falling_back - # A request that never reached the server says nothing about whether it publishes PRM, so once - # the other candidates answer 404 the flow stops instead of moving to the legacy authorization base; - # the TypeScript and Python SDKs propagate the error the same way. - challenge_url = "https://srv.example.com/prm.json" - stub_request(:get, challenge_url).to_raise(Faraday::ConnectionFailed.new("connection refused")) - stub_prm_not_found - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: challenge_url) - end - - assert_match(/Faraday::ConnectionFailed/, error.message) - assert_not_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - assert_not_requested(:post, "https://srv.example.com/register") - end - - def test_run_reports_a_prm_candidate_url_without_its_query_in_the_discovery_error - # The candidate URL comes from the server's `WWW-Authenticate` challenge and lands in every log line - # the error reaches, so the query is dropped, while the path keeps the spelling that was requested - # (`%2E` is not decoded) so the line can be matched against the server's access log. - challenge_url = "https://srv.example.com/prm%2Ejson?token=abc" - stub_request(:get, challenge_url).to_raise(Faraday::ConnectionFailed.new("connection refused")) - stub_prm_not_found - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: challenge_url) - end - - assert_includes(error.message, "GET https://srv.example.com/prm%2Ejson raised Faraday::ConnectionFailed: connection refused; GET") - refute_includes(error.message, "token=abc") - end - - def test_run_cuts_an_overlong_prm_candidate_url_in_the_discovery_error - # The challenge URL is the server's to choose, so its length is bounded before it lands in the message. - challenge_url = "https://srv.example.com/#{"a" * 5000}/prm.json" - stub_request(:get, challenge_url).to_raise(Faraday::ConnectionFailed.new("connection refused")) - stub_prm_not_found - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: challenge_url) - end - - assert_includes(error.message, "GET #{challenge_url[0, Flow::METADATA_URL_MAX_LENGTH - 3]}... raised Faraday::ConnectionFailed") - refute_includes(error.message, "a" * (Flow::METADATA_URL_MAX_LENGTH - 3)) - end - - def test_run_bounds_the_transport_error_message_in_the_discovery_error - # A caller-supplied client can raise with server-chosen text in the message (Faraday's `raise_error` middleware repeats - # the status line and the request URL), so it is bounded like the parser's message. - stub_request(:get, @prm_url).to_raise(Faraday::ConnectionFailed.new("x" * 5000)) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_includes(error.message, "raised Faraday::ConnectionFailed: #{"x" * 125}...; GET") - refute_includes(error.message, "x" * 126) - end - - def test_run_bounds_the_parser_message_in_the_discovery_error - # json before 2.10 repeats the remaining source in `JSON::ParserError#message`, so a malformed body - # could otherwise put up to the response cap into the message once per candidate. - stub_request(:get, @prm_url).to_return(status: 200, headers: { "Content-Type" => "application/json" }, body: "{") - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 503) - JSON.stubs(:parse).raises(JSON::ParserError, "unexpected token at '#{"{" * 5000}'") - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - # `METADATA_DIAGNOSTIC_MAX_LENGTH` is 128: the first 125 characters survive, then three dots. - assert_includes(error.message, <<~MESSAGE.chomp) - returned a body that is not JSON: unexpected token at '#{"{" * 104}...; \ - GET https://srv.example.com/.well-known/oauth-protected-resource returned 503. - MESSAGE - - refute_includes(error.message, "{" * 105) - end - - def test_run_surfaces_a_server_error_during_prm_discovery_instead_of_falling_back - # A `5xx` or `429` says nothing about what the server publishes either, even when a later candidate answers 404; - # the Python SDK refuses the legacy path the same way. - [503, 429].each do |status| - stub_request(:get, @prm_url).to_return(status: status) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - - error = assert_raises(Flow::MetadataUnreachableError, "status #{status}") do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/returned #{status}/, error.message) - end - - assert_not_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - assert_not_requested(:post, "https://srv.example.com/register") - end - - def test_run_keeps_a_server_error_in_mind_when_a_later_candidate_is_unusable - # An unusable document from a later candidate must not turn an earlier `503` into "nothing published". - challenge_url = "https://srv.example.com/prm.json" - stub_request(:get, challenge_url).to_return(status: 503) - stub_request(:get, @prm_url).to_return(status: 200, headers: { "Content-Type" => "application/json" }, body: "[]") - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: challenge_url) - end - - assert_match(/returned 503/, error.message) - assert_not_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - end - - def test_run_uses_a_later_prm_candidate_when_the_challenge_url_serves_an_unusable_document - # The setup stubs a valid document at the well-known path; a broken one at the challenge URL is skipped. - challenge_url = "https://srv.example.com/prm.json" - stub_request(:get, challenge_url).to_return(status: 200, headers: { "Content-Type" => "application/json" }, body: "[]") - - result = Flow.new(provider: build_legacy_discovery_provider({})).run!(server_url: @server_url, resource_metadata_url: challenge_url) - - assert_equal(:authorized, result) - assert_requested(:get, @prm_url) - end - - def test_run_recovers_authorization_server_metadata_from_a_later_candidate_after_a_network_error - # The OAuth document being unreachable must not stop the OpenID one from being tried. - stub_request(:get, @as_metadata_url).to_raise(Faraday::TimeoutError.new("execution expired")) - stub_request(:get, "#{@auth_base}/.well-known/openid-configuration").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - result = run_authorization_flow - - assert_equal(:authorized, result) - assert_requested(:get, "#{@auth_base}/.well-known/openid-configuration") - end - - def test_run_recovers_authorization_server_metadata_from_a_later_candidate_after_an_unusable_document - # An OAuth document that is not JSON, or not a JSON object, must not stop the OpenID one from being tried. - stub_request(:get, "#{@auth_base}/.well-known/openid-configuration").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - ["{", "[]"].each do |body| - stub_request(:get, @as_metadata_url).to_return(status: 200, headers: { "Content-Type" => "application/json" }, body: body) - - assert_equal(:authorized, run_authorization_flow, "body #{body.inspect}") - end - - assert_requested(:get, "#{@auth_base}/.well-known/openid-configuration", times: 2) - end - - def test_refresh_surfaces_a_network_error_during_prm_discovery_instead_of_falling_back - stub_request(:get, @prm_url).to_raise(Faraday::TimeoutError.new("execution expired")) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - provider = build_legacy_discovery_provider({}) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - assert_not_requested(:post, "https://srv.example.com/token") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_refresh_surfaces_a_server_error_during_prm_discovery_instead_of_falling_back - stub_request(:get, @prm_url).to_return(status: 503) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - provider = build_legacy_discovery_provider({}) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::MetadataUnreachableError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/returned 503/, error.message) - assert_not_requested(:post, "https://srv.example.com/token") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - # Builds a provider for the legacy-discovery tests, capturing the authorization URL so tests can assert - # which endpoint was used. - def build_legacy_discovery_provider(holder) - Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - holder[:authorization_url] = url - holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", holder[:state]] }, - ) - end - - def stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource/mcp").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - end - - # Legacy 2025-03-26 shape: no PRM, AS metadata served from the MCP server origin with the given `issuer` - # and the OAuth endpoints under a path prefix. - def stub_legacy_metadata_with_prefixed_endpoints(issuer:, iss_supported: false) - stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: issuer, - authorization_endpoint: "https://srv.example.com/oauth/authorize", - token_endpoint: "https://srv.example.com/oauth/token", - registration_endpoint: "https://srv.example.com/oauth/register", - response_types_supported: ["code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - authorization_response_iss_parameter_supported: iss_supported, - ), - ) - stub_request(:post, "https://srv.example.com/oauth/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "legacy-client"), - ) - stub_request(:post, "https://srv.example.com/oauth/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "legacy-token", token_type: "Bearer", expires_in: 3600), - ) - end - - def test_run_falls_back_to_server_origin_metadata_without_prm - # The document names the origin, so the RFC 8414 Section 3.3 check passes and its prefixed endpoints are used. - stub_legacy_metadata_with_prefixed_endpoints(issuer: "https://srv.example.com") - - holder = {} - provider = build_legacy_discovery_provider(holder) - - result = Flow.new(provider: provider).run!(server_url: @server_url) - - assert_equal(:authorized, result) - assert_equal("legacy-token", provider.access_token) - assert_equal("https://srv.example.com", provider.tokens["issuer"]) - assert_equal("/oauth/authorize", holder[:authorization_url].path) - assert_requested(:post, "https://srv.example.com/oauth/register") - assert_requested(:post, "https://srv.example.com/oauth/token") - end - - def test_run_accepts_legacy_metadata_naming_the_origin_with_a_trailing_slash - # A root issuer rendered as `https://host/` names the same server; the TypeScript and Python SDKs accept it too, - # and the document's spelling is what the RFC 9207 `iss` and the recorded issuer carry. - stub_legacy_metadata_with_prefixed_endpoints(issuer: "https://srv.example.com/", iss_supported: true) - - holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", holder[:state], "https://srv.example.com/"] }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url) - - assert_equal(:authorized, result) - assert_equal("https://srv.example.com/", provider.tokens["issuer"]) - end - - def test_run_refuses_legacy_metadata_whose_issuer_is_not_the_origin - # RFC 8414 Section 3.3 applies on the legacy path as well: the 2025-03-26 spec places the metadata - # at the origin, so an issuer under a path prefix is a mismatch, as it is for the TypeScript and Python SDKs. - stub_legacy_metadata_with_prefixed_endpoints(issuer: "https://srv.example.com/oauth") - - holder = {} - provider = build_legacy_discovery_provider(holder) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url) - end - - assert_match(/`issuer` does not match/, error.message) - assert_nil(holder[:authorization_url]) - assert_not_requested(:post, "https://srv.example.com/oauth/register") - assert_not_requested(:post, "https://srv.example.com/oauth/token") - end - - def test_run_falls_back_to_default_endpoints_without_any_metadata - # Legacy 2025-03-26 "Fallbacks for Servers without Metadata Discovery": with no PRM and no AS metadata, - # the client MUST use /authorize, /token, and /register at the authorization base URL, still sending PKCE S256. - stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/openid-configuration").to_return(status: 404) - stub_request(:post, "https://srv.example.com/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "legacy-client"), - ) - stub_request(:post, "https://srv.example.com/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "legacy-token", token_type: "Bearer", expires_in: 3600), - ) - - holder = {} - provider = build_legacy_discovery_provider(holder) - - result = Flow.new(provider: provider).run!(server_url: @server_url) - - assert_equal(:authorized, result) - assert_equal("/authorize", holder[:authorization_url].path) - query = URI.decode_www_form(holder[:authorization_url].query).to_h - assert_equal("S256", query["code_challenge_method"]) - refute_empty(query["code_challenge"].to_s) - assert_requested(:post, "https://srv.example.com/register") - assert_requested(:post, "https://srv.example.com/token") do |req| - URI.decode_www_form(req.body).to_h["code_verifier"].to_s != "" - end - end - - def test_run_client_credentials_without_prm_uses_the_legacy_authorization_base - # A PRM-less server takes the legacy path for this grant too: metadata at the origin, no advertised scopes, - # so the provider's own scope is used and the tokens are bound to the origin. - stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: "https://srv.example.com", - token_endpoint: "https://srv.example.com/token", - token_endpoint_auth_methods_supported: ["client_secret_basic"], - ), - ) - stub_request(:post, "https://srv.example.com/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "legacy-token", token_type: "Bearer", expires_in: 3600), - ) - provider = ClientCredentialsProvider.new(client_id: "cc-client", client_secret: "cc-secret", scope: "mcp:read") - - result = Flow.new(provider: provider).run!(server_url: @server_url) - - assert_equal(:authorized, result) - assert_equal("legacy-token", provider.access_token) - assert_equal("https://srv.example.com", provider.tokens["issuer"]) - assert_requested(:post, "https://srv.example.com/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "client_credentials" && - form["scope"] == "mcp:read" && - form["resource"] == "https://srv.example.com/mcp" - end - end - - def test_run_jwt_bearer_without_any_metadata_uses_the_legacy_default_endpoints - stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/openid-configuration").to_return(status: 404) - stub_request(:post, "https://srv.example.com/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "legacy-token", token_type: "Bearer", expires_in: 3600), - ) - received = nil - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(audience:, resource:) { - received = { audience: audience, resource: resource } - "id-jag-assertion" - }, - ) - - result = Flow.new(provider: provider).run!(server_url: @server_url) - - assert_equal(:authorized, result) - # The assertion is minted for the legacy authorization base, which is the only identity such a server has. - assert_equal({ audience: "https://srv.example.com", resource: "https://srv.example.com/mcp" }, received) - assert_equal("https://srv.example.com", provider.tokens["issuer"]) - assert_requested(:post, "https://srv.example.com/token") do |req| - form = URI.decode_www_form(req.body).to_h - - form["grant_type"] == "urn:ietf:params:oauth:grant-type:jwt-bearer" && - form["assertion"] == "id-jag-assertion" && - form["resource"] == "https://srv.example.com/mcp" && - !form.key?("scope") - end - end - - def test_run_legacy_fallback_rejects_insecure_authorization_base - # The Communication Security requirement still applies on the legacy path: a remote plain-http origin must not - # become the authorization base URL. - stub_request(:get, "http://internal.example.com/.well-known/oauth-protected-resource/mcp").to_return(status: 404) - stub_request(:get, "http://internal.example.com/.well-known/oauth-protected-resource").to_return(status: 404) - - holder = {} - provider = build_legacy_discovery_provider(holder) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: "http://internal.example.com/mcp") - end - - assert_match(/legacy authorization base URL/, error.message) - end - - def test_run_keeps_strict_issuer_validation_when_prm_is_present - # The legacy issuer-check relaxation must not leak into the modern path: with PRM present, - # a mismatched issuer still aborts. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: "https://evil.example.com", - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - ), - ) - - holder = {} - provider = build_legacy_discovery_provider(holder) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/`issuer` does not match/, error.message) - end - - # Legacy metadata served at the MCP server origin that claims the identity of another authorization server, - # with every endpoint at the origin itself. The claim fails the RFC 8414 check, so none of these endpoints is reached. - def stub_legacy_metadata_claiming(issuer) - stub_prm_not_found - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: issuer, - authorization_endpoint: "https://srv.example.com/authorize", - token_endpoint: "https://srv.example.com/token", - registration_endpoint: "https://srv.example.com/register", - code_challenge_methods_supported: ["S256"], - ), - ) - stub_request(:post, "https://srv.example.com/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "legacy-client"), - ) - stub_request(:post, "https://srv.example.com/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "legacy-token", token_type: "Bearer", expires_in: 3600), - ) - end - - def test_run_refuses_legacy_metadata_claiming_another_authorization_server_before_the_validator - stub_legacy_metadata_claiming(@auth_base) - recorder = [] - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) { recorder << :redirected }, - callback_handler: -> { ["test-auth-code", "state"] }, - authorization_request_validator: ->(request) { - recorder << request - true - }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url) - end - - assert_match(/`issuer` does not match/, error.message) - assert_empty(recorder) - assert_not_requested(:post, "https://srv.example.com/register") - assert_not_requested(:post, "https://srv.example.com/token") - end - - def test_refresh_refuses_legacy_metadata_claiming_the_issuer_that_minted_the_tokens - # The tokens came from https://auth.example.com; a PRM-less server claiming that issuer at its own origin - # must not receive them, so the refresh token stays for the server that issued it. - stub_legacy_metadata_claiming(@auth_base) - provider = build_legacy_discovery_provider({}) - provider.save_client_information("client_id" => "conf-client", "client_secret" => "conf-secret") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt", "issuer" => @auth_base) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url) - end - - assert_match(/`issuer` does not match/, error.message) - assert_not_requested(:post, "https://srv.example.com/token") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_run_does_not_present_client_information_bound_elsewhere_when_legacy_metadata_claims_that_issuer - # Client information issued by https://auth.example.com is bound to it (SEP-2352); a PRM-less server claiming - # that issuer is refused before the credentials could be presented anywhere. - stub_legacy_metadata_claiming(@auth_base) - holder = {} - provider = build_legacy_discovery_provider(holder) - provider.save_client_information("client_id" => "conf-client", "client_secret" => "conf-secret", "issuer" => @auth_base) - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url) - end - - assert_nil(holder[:authorization_url]) - assert_not_requested(:post, "https://srv.example.com/register") - assert_not_requested(:post, "https://srv.example.com/token") - assert_equal("conf-secret", provider.client_information["client_secret"]) - assert_equal(@auth_base, provider.client_information["issuer"]) - end - - def test_run_raises_when_prm_authorization_servers_is_not_an_array - # `authorization_servers` MUST be an Array per RFC 9728. A misbehaving - # PRM that returns a String would otherwise reach `.first` and raise - # raw `NoMethodError` out of the SDK. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: "https://auth.example.com", - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/authorization_servers/i, error.message) - end - - def test_run_refuses_an_authorization_server_metadata_body_over_the_cap - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: over_cap_body, - ) - - error = assert_raises(Flow::AuthorizationError) { run_authorization_flow } - - assert_match(/exceeds \d+ bytes/, error.message) - end - - def test_run_refuses_a_protected_resource_metadata_body_over_the_cap - # An oversized document is refused outright rather than treated as unpublished, so the flow stops - # without the legacy fallback. The padded document is valid JSON naming an authorization server, - # so contacting that server is exactly what would happen if the body had been read: - # the assertion below fails if the cap stops working. - stub_request(:any, %r{\Ahttps://srv\.example\.com/}).to_return(status: 404) - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - padding: "a" * (4 * 1024 * 1024), - ), - ) - - error = assert_raises(Flow::AuthorizationError) { run_authorization_flow } - - assert_match(/exceeds \d+ bytes/, error.message) - assert_not_requested(:get, @as_metadata_url) - assert_not_requested(:get, "https://srv.example.com/.well-known/oauth-authorization-server") - end - - def test_run_refuses_a_dynamic_client_registration_body_over_the_cap - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: over_cap_body, - ) - - error = assert_raises(Flow::AuthorizationError) { run_authorization_flow } - - assert_match(/exceeds \d+ bytes/, error.message) - end - - def test_run_refuses_a_token_endpoint_body_over_the_cap - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: over_cap_body, - ) - - error = assert_raises(Flow::AuthorizationError) { run_authorization_flow } - - assert_match(/exceeds \d+ bytes/, error.message) - end - - # One byte past the cap, so the three request wrappers are each proven to install the streaming callback. - # A wrapper that forgot it would buffer this whole body and parse it. - def over_cap_body - "a" * (4 * 1024 * 1024 + 1) - end - - def test_run_raises_when_token_response_is_not_a_json_object - # The token endpoint MUST return a JSON object per RFC 6749 §5.1. - # A non-object body would otherwise be persisted into the provider - # and raise raw exceptions the next time `provider.access_token` - # is read. - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: "[]", - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/Token endpoint response is not a JSON object/i, error.message) - end - - def test_run_treats_whitespace_only_stored_client_id_as_unregistered - # `" "` (whitespace only) is just as meaningless as `""`. - # The check on stored client_information must trigger DCR rather than - # passing the blank value through to the token endpoint. - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "registered-after-whitespace"), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information("client_id" => " ") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - assert_equal("registered-after-whitespace", provider.client_information.fetch("client_id")) - end - - def test_run_raises_when_as_metadata_is_not_a_json_object - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: "null", - ) - stub_request(:get, "#{@auth_base}/.well-known/openid-configuration").to_return(status: 404) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/not a JSON object/i, error.message) - end - - def test_run_raises_when_dcr_response_has_blank_client_id - # A blank `client_id` is just as invalid as a missing one: peer SDKs - # (TS / Python) require a non-empty string, and treating `""` as - # truthy would let a misbehaving AS register a "client" the SDK can - # never authenticate as. - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "", client_name: "blank-id"), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/client_id/i, error.message) - end - - def test_run_treats_blank_stored_client_id_as_unregistered - # Pre-stored `client_information` with a blank `client_id` must - # trigger DCR rather than skipping registration; otherwise - # the token endpoint receives `client_id=""` which the AS will reject. - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "registered-after-blank"), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information("client_id" => "") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - assert_equal("registered-after-blank", provider.client_information.fetch("client_id")) - end - - def test_run_raises_when_dcr_response_lacks_client_id - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_name: "test-but-no-id"), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/client_id/i, error.message) - end - - # Builds a provider whose callback returns the given `iss` shape: - # `:omitted` keeps the legacy 2-element `[code, state]` form, any other value (including nil) returns - # the 3-element `[code, state, iss]` form that opts into SEP-2468 / RFC 9207 issuer validation. - def build_iss_validation_provider(callback_iss: :omitted) - state_holder = {} - callback_handler = if callback_iss == :omitted - -> { ["test-auth-code", state_holder[:state]] } - else - -> { ["test-auth-code", state_holder[:state], callback_iss] } - end - - Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: callback_handler, - ) - end - - # Re-stubs the AS metadata with `authorization_response_iss_parameter_supported: true`. - def stub_as_metadata_with_iss_support - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - authorization_response_iss_parameter_supported: true, - ), - ) - end - - def test_run_completes_when_authorization_response_iss_matches_issuer - provider = build_iss_validation_provider(callback_iss: @auth_base) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - assert_equal("test-token-from-flow", provider.access_token) - end - - def test_run_aborts_before_code_exchange_when_authorization_response_iss_mismatches - provider = build_iss_validation_provider(callback_iss: "https://evil.example.com") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - # Per RFC 9207, the client MUST NOT send the authorization code to a token endpoint after an `iss` mismatch. - assert_match(/`iss` does not match/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_aborts_when_iss_is_missing_but_as_advertises_iss_support - stub_as_metadata_with_iss_support - provider = build_iss_validation_provider(callback_iss: nil) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/carried no `iss`/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_completes_with_legacy_two_element_callback_even_when_as_advertises_iss_support - stub_as_metadata_with_iss_support - provider = build_iss_validation_provider - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - end - - def test_run_completes_when_iss_is_missing_and_as_does_not_advertise_iss_support - provider = build_iss_validation_provider(callback_iss: nil) - - result = Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:authorized, result) - end - - def test_run_validates_present_iss_even_when_as_does_not_advertise_iss_support - provider = build_iss_validation_provider(callback_iss: "https://evil.example.com") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_run_skips_dcr_when_client_information_already_stored - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information("client_id" => "preregistered-client") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal("test-token-from-flow", provider.access_token) - assert_not_requested(:post, "#{@auth_base}/register") - end - - def test_run_accepts_symbol_keys_in_preregistered_client_information - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information(client_id: "preregistered-symbol") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal("test-token-from-flow", provider.access_token) - assert_not_requested(:post, "#{@auth_base}/register") - end - - # Builds a provider that completes the non-interactive authorization - # flow against the stubs from `setup`, for the SEP-2352 issuer-binding - # tests. - def build_issuer_binding_provider - state_holder = {} - Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - end - - def test_run_skips_dcr_when_stored_issuer_matches - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - provider = build_issuer_binding_provider - provider.save_client_information("client_id" => "preregistered-client", "issuer" => @auth_base) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal("test-token-from-flow", provider.access_token) - assert_not_requested(:post, "#{@auth_base}/register") - end - - def test_run_reregisters_when_authorization_server_changes - provider = build_issuer_binding_provider - provider.save_client_information("client_id" => "old-client", "issuer" => "https://other-as.example.com") - provider.save_tokens("access_token" => "old-as-token") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - info = provider.client_information - assert_equal("test-client", info["client_id"]) - assert_equal(@auth_base, info["issuer"]) - end - - def test_run_clears_stale_tokens_when_authorization_server_changes - # Abort the flow right after the discard (DCR fails) to observe that tokens minted by - # the old authorization server were wiped before any re-registration attempt. - stub_request(:post, "#{@auth_base}/register").to_return(status: 500, body: "") - - provider = build_issuer_binding_provider - provider.save_client_information("client_id" => "old-client", "issuer" => "https://other-as.example.com") - provider.save_tokens("access_token" => "old-as-token", "refresh_token" => "old-as-rt") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_nil(provider.tokens) - assert_nil(provider.client_information) - end - - def test_run_binds_legacy_client_information_to_issuer_on_first_use - # Credentials persisted before issuer binding existed (or supplied as pre-registered credentials) - # are reused and stamped with the current issuer rather than discarded. - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - provider = build_issuer_binding_provider - provider.save_client_information("client_id" => "preregistered-client") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_not_requested(:post, "#{@auth_base}/register") - assert_equal(@auth_base, provider.client_information["issuer"]) - end - - def test_run_binds_symbol_keyed_client_information_to_issuer_on_first_use - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - provider = build_issuer_binding_provider - provider.save_client_information(client_id: "preregistered-symbol") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_not_requested(:post, "#{@auth_base}/register") - assert_equal("test-token-from-flow", provider.access_token) - assert_equal(@auth_base, provider.client_information["issuer"]) - end - - def test_run_reuses_portable_cimd_client_id_across_authorization_servers - # Per SEP-2352, a CIMD `client_id` (an HTTPS URL) is portable across authorization servers: - # reuse it and re-bind the issuer instead of discarding the registration. - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - provider = build_issuer_binding_provider - provider.save_client_information( - "client_id" => "https://app.example.com/client-metadata.json", - "issuer" => "https://other-as.example.com", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_not_requested(:post, "#{@auth_base}/register") - info = provider.client_information - assert_equal("https://app.example.com/client-metadata.json", info["client_id"]) - assert_equal(@auth_base, info["issuer"]) - end - - def test_run_persists_issuer_with_dcr_client_information - provider = build_issuer_binding_provider - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - info = provider.client_information - assert_equal("test-client", info["client_id"]) - assert_equal(@auth_base, info["issuer"]) - end - - def test_run_skips_dcr_when_as_supports_cimd_and_provider_has_cimd_url - # When the AS advertises Client ID Metadata Document support and the provider was configured with a CIMD URL, - # the SDK uses the URL as the OAuth `client_id` and does not call /register. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: true, - ), - ) - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - captured_authorization_url = nil - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - captured_authorization_url = url - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_not_requested(:post, "#{@auth_base}/register") - query = URI.decode_www_form(captured_authorization_url.query).to_h - assert_equal("https://app.example.com/client-metadata.json", query["client_id"]) - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["client_id"] == "https://app.example.com/client-metadata.json" - end - # The CIMD URL is NOT persisted to storage: AS metadata is re-read on every flow, - # so a later AS that no longer advertises CIMD will not be sent a stale CIMD `client_id`. - assert_nil(provider.client_information) - end - - def test_run_falls_back_to_dcr_when_provider_has_cimd_url_but_as_does_not_advertise_support - # The provider may carry a CIMD URL across multiple servers; if a particular AS does not advertise CIMD support, - # the SDK must still register via DCR rather than send an unsupported `client_id`. - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - assert_equal("test-client", provider.client_information["client_id"]) - end - - def test_run_does_not_enter_cimd_branch_when_support_advertised_as_string_false - # A misconfigured AS that ships `"client_id_metadata_document_supported": "false"` - # is truthy in Ruby. The SDK must NOT route through CIMD on truthy non-boolean values; - # only a JSON `boolean true` opts in. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: "false", - ), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - assert_equal("test-client", provider.client_information["client_id"]) - end - - def test_run_does_not_enter_cimd_branch_when_support_advertised_as_string_true - # Mirror of the previous test for the other truthy non-boolean value: - # `"true"` is also a string, not the JSON boolean the spec requires. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: "true", - ), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - end - - def test_run_does_not_persist_cimd_client_id_so_later_flow_recovers_when_as_drops_support - # Regression for the storage side-effect: if the SDK persisted the CIMD URL on the first flow, - # a second flow against an AS that no longer advertises CIMD support would still send the URL as - # the `client_id` and skip DCR. Re-running with the same provider must honour the updated AS metadata. - shared_storage = InMemoryStorage.new - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - storage: shared_storage, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - # First flow: AS supports CIMD, so DCR is skipped. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: true, - ), - ) - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - assert_nil(shared_storage.client_information, "CIMD client_id must not be persisted") - - # Second flow: AS no longer advertises CIMD. The SDK must register via DCR rather than reuse a stale CIMD URL. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/register") - assert_equal("test-client", shared_storage.client_information["client_id"]) - end - - def test_run_skips_cimd_when_pre_registered_client_information_exists - # Pre-registered `client_information` wins over CIMD: the user explicitly chose a DCR-style identity, - # so neither DCR nor the CIMD URL should overwrite it. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: true, - ), - ) - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - captured_authorization_url = nil - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - captured_authorization_url = url - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - provider.save_client_information("client_id" => "preregistered-client") - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - query = URI.decode_www_form(captured_authorization_url.query).to_h - assert_equal("preregistered-client", query["client_id"]) - end - - def test_run_uses_basic_auth_when_token_endpoint_auth_method_is_client_secret_basic - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "client_secret_basic", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information( - "client_id" => "pre-registered-client", - "client_secret" => "pre-registered-secret", - "token_endpoint_auth_method" => "client_secret_basic", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - expected = "Basic " + Base64.strict_encode64("pre-registered-client:pre-registered-secret") - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - req.headers["Authorization"] == expected && - !form.key?("client_id") && - !form.key?("client_secret") - end - end - - def test_run_form_urlencodes_basic_auth_credentials_with_special_characters - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "client_secret_basic", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - # Per RFC 6749 Section 2.3.1, credentials must be `application/x-www-form-urlencoded` - # before being joined with ":" and base64-encoded. A `:` in the secret would - # otherwise be ambiguous with the username/password separator. - provider.save_client_information( - "client_id" => "client:with colon", - "client_secret" => "secret:with:colons and spaces", - "token_endpoint_auth_method" => "client_secret_basic", - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - encoded_id = URI.encode_www_form_component("client:with colon") - encoded_secret = URI.encode_www_form_component("secret:with:colons and spaces") - expected = "Basic " + Base64.strict_encode64("#{encoded_id}:#{encoded_secret}") - assert_requested(:post, "#{@auth_base}/token") do |req| - req.headers["Authorization"] == expected - end - end - - def test_run_rejects_non_https_resource_metadata_url - # `WWW-Authenticate` may carry a `resource_metadata=` URL we have never - # seen before; if it isn't HTTPS-or-loopback, an attacker could lure us - # into fetching a doctored PRM document over plain HTTP. - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!( - server_url: @server_url, - resource_metadata_url: "http://attacker.example.com/.well-known/oauth-protected-resource", - ) - end - - assert_match(/resource_metadata|HTTPS|Communication Security/i, error.message) - end - - def test_run_does_not_fetch_a_resource_metadata_url_off_the_server_origin - # A server that answers 401 chooses the `resource_metadata` URL, and discovery puts it first - # in the candidate list. Left unchecked, a single response header aims the client's first OAuth request - # at any host it can route to, including the cloud metadata address. The assertion that matters is not - # the raise but `assert_not_requested`: nothing downstream can un-send a request. - metadata_url = "https://169.254.169.254/latest/meta-data/iam/" - stub_request(:get, metadata_url).to_return(status: 200, body: "{}") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!( - server_url: @server_url, - resource_metadata_url: metadata_url, - ) - end - - assert_not_requested(:get, metadata_url) - assert_match(/resource_metadata/i, error.message) - assert_match(/origin/i, error.message) - end - - def test_run_does_not_fetch_an_https_resource_metadata_url_on_a_foreign_public_origin - # The scheme check alone passes this one: it is HTTPS, just not the server's. - metadata_url = "https://attacker.example.com/.well-known/oauth-protected-resource" - stub_request(:get, metadata_url).to_return(status: 200, body: "{}") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!( - server_url: @server_url, - resource_metadata_url: metadata_url, - ) - end - - assert_not_requested(:get, metadata_url) - end - - def test_refresh_does_not_fetch_a_resource_metadata_url_off_the_server_origin - # `refresh!` reads the same header on a 401 and must gate it identically; - # otherwise the token-refresh path stays reachable after `run!` is closed. - metadata_url = "https://169.254.169.254/latest/meta-data/iam/" - stub_request(:get, metadata_url).to_return(status: 200, body: "{}") - - provider = ssrf_test_provider - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!( - server_url: @server_url, - resource_metadata_url: metadata_url, - ) - end - - assert_not_requested(:get, metadata_url) - end - - def test_run_does_not_contact_an_authorization_server_on_a_private_address - # One hop deeper than the `resource_metadata` URL: the server serves its own PRM from its own origin, - # then names a private address as its authorization server. Same-origin cannot see this one, - # so the range check has to. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: @server_url, - authorization_servers: ["https://169.254.169.254"], - ), - ) - stub_request(:get, %r{\Ahttps://169\.254\.169\.254/}).to_return(status: 200, body: "{}") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:get, %r{\Ahttps://169\.254\.169\.254/}) - assert_match(/private network/i, error.message) - end - - def test_run_does_not_contact_an_authorization_server_spelled_as_a_packed_integer - # `0xa9fea9fe` is 169.254.169.254 written for `inet_aton`. The connection resolves it to - # the same address, so the previous test's protection has to survive the rewrite. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: @server_url, - authorization_servers: ["https://0xa9fea9fe"], - ), - ) - stub_request(:get, %r{\Ahttps://0xa9fea9fe/}).to_return(status: 200, body: "{}") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:get, %r{\Ahttps://0xa9fea9fe/}) - assert_match(/private network/i, error.message) - end - - def test_run_does_not_post_to_a_token_endpoint_on_a_private_address - # The token endpoint receives the client credentials and the authorization code, - # so an AS document that relocates it inside the client's network is a credential disclosure, - # not just a probe. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "https://10.0.0.5/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - stub_request(:post, "https://10.0.0.5/token").to_return(status: 200, body: "{}") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:post, "https://10.0.0.5/token") - assert_match(/private network/i, error.message) - end - - def test_run_does_not_post_to_a_registration_endpoint_on_a_private_address - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "https://192.168.1.1/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - stub_request(:post, "https://192.168.1.1/register").to_return(status: 201, body: "{}") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: ssrf_test_provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_not_requested(:post, "https://192.168.1.1/register") - end - - def test_run_allows_a_private_authorization_server_when_the_mcp_server_is_also_private - # The shape the conformance harness runs and the shape local development takes: - # the MCP server and the authorization server sit on two loopback ports. - # Once the caller has pointed the client at a private address, the authorization server - # living there too is not an escalation, and refusing it would break every local setup. - server_url = "http://localhost:9292/mcp" - prm_url = "http://localhost:9292/.well-known/oauth-protected-resource/mcp" - auth_base = "http://localhost:9393" - - stub_request(:get, prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: server_url, authorization_servers: [auth_base]), - ) - stub_request(:get, "#{auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: auth_base, - authorization_endpoint: "#{auth_base}/authorize", - token_endpoint: "#{auth_base}/token", - registration_endpoint: "#{auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - stub_request(:post, "#{auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "local-client"), - ) - stub_request(:post, "#{auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "local-token", token_type: "Bearer", expires_in: 3600), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - result = Flow.new(provider: provider).run!(server_url: server_url, resource_metadata_url: prm_url) - - assert_equal(:authorized, result) - assert_equal("local-token", provider.access_token) - end - - def test_run_rejects_when_as_metadata_issuer_does_not_match - # RFC 8414 Section 3.3: the AS metadata's `issuer` value MUST equal the discovery URL. - # A metadata document advertising a different issuer than the one PRM pointed at is treated - # as a confused-deputy attempt. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: "https://other-auth.example.com", - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issuer/i, error.message) - end - - def test_run_rejects_when_as_metadata_issuer_differs_by_trailing_slash - # RFC 8414 Section 3.3 requires the issuer to be identical, not "equivalent after normalization". - # `https://auth.example.com` and `https://auth.example.com/` are different strings and MUST NOT match. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: "#{@auth_base}/", - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issuer/i, error.message) - end - - def test_run_rejects_when_as_metadata_issuer_differs_by_case - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base.upcase, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issuer/i, error.message) - end - - def test_run_rejects_when_as_metadata_lacks_issuer - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issuer/i, error.message) - end - - def test_run_rejects_non_https_authorization_server - # Communication Security: an `http://` authorization server URL (other - # than loopback) MUST be refused. Returning a non-HTTPS auth server - # from a hijacked PRM would let the attacker steer the client at - # an endpoint they control to harvest tokens. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: ["http://auth.example.com"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/HTTPS|Communication Security/i, error.message) - end - - def test_run_rejects_non_https_token_endpoint - # Even when PRM and AS metadata discovery happen over HTTPS, the AS - # metadata document itself can advertise an `http://` token endpoint. - # That endpoint is where the bearer token lands, so it MUST be rejected. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "http://insecure.example.com/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/HTTPS|Communication Security|token_endpoint/i, error.message) - end - - def test_refresh_swaps_refresh_token_for_new_access_token - # Refresh should NOT hit /register (no DCR) and SHOULD post - # grant_type=refresh_token with the saved refresh_token. - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token", "refresh_token" => "saved-rt")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer", expires_in: 3600), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - result = Flow.new(provider: provider).refresh!( - server_url: @server_url, - resource_metadata_url: @prm_url, - ) - - assert_equal(:refreshed, result) - assert_equal("fresh-at", provider.access_token) - # New response did not include a refresh_token, so the old one is preserved (RFC 6749 Section 6). - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_refresh_with_client_secret_basic_omits_client_id_from_body - # Stored credentials without an auth method default to Basic. Refresh - # must also omit the body `client_id` when using that fallback. - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer", expires_in: 3600), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "conf-client", "client_secret" => "conf-secret") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - req.headers["Authorization"] == "Basic " + Base64.strict_encode64("conf-client:conf-secret") && - !form.key?("client_id") && - !form.key?("client_secret") - end - end - - def test_run_records_the_issuer_that_minted_the_tokens - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(@auth_base, provider.tokens["issuer"]) - end - - def test_refresh_refuses_an_authorization_server_that_did_not_issue_the_tokens - # The stored tokens came from a different authorization server, so this refresh token must not reach the one named now. - stub_request(:post, "#{@auth_base}/token").to_raise(StandardError.new("must not reach the token endpoint.")) - - provider = refresh_only_provider - provider.save_tokens( - "access_token" => "stale-at", - "refresh_token" => "saved-rt", - "issuer" => "https://issued-by.example.com", - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/issued by a different authorization server/, error.message) - - # Left in place: it is still good at the server that issued it, and the caller answers this by running the full authorization flow. - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_refresh_proceeds_for_tokens_stored_before_the_issuer_was_recorded - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer"), - ) - - provider = refresh_only_provider - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - result = Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal(:refreshed, result) - - # Recorded on the way out, so the binding takes effect from here on. - assert_equal(@auth_base, provider.tokens["issuer"]) - end - - def test_refresh_succeeds_when_stored_issuer_matches - stub_request(:post, "#{@auth_base}/token").with( - body: hash_including("grant_type" => "refresh_token", "refresh_token" => "saved-rt"), - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer", expires_in: 3600), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client", "issuer" => @auth_base) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - result = Flow.new(provider: provider).refresh!( - server_url: @server_url, - resource_metadata_url: @prm_url, - ) - - assert_equal(:refreshed, result) - assert_equal("fresh-at", provider.access_token) - end - - def test_refresh_raises_when_stored_issuer_differs - # Per SEP-2352, another authorization server's credentials must not be replayed at this token endpoint; - # the caller falls back to the full flow, which discards the stale registration and re-registers. - stub_request(:post, "#{@auth_base}/token").to_raise(StandardError.new("Token endpoint should not be called.")) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "old-client", "issuer" => "https://other-as.example.com") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/different authorization server/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_uses_cimd_url_as_client_id_when_provider_has_cimd_and_as_supports_it - # Regression: the CIMD branch in `ensure_client_registered` does not persist `client_information`, - # so a refresh call that requires stored client info would always fail after a CIMD-only flow. - # `refresh!` must reconstruct the CIMD `client_id` from live AS metadata + the provider URL on every call. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: true, - ), - ) - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - stub_request(:post, "#{@auth_base}/token").with( - body: hash_including( - "grant_type" => "refresh_token", - "refresh_token" => "saved-rt", - "client_id" => "https://app.example.com/client-metadata.json", - ), - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer", expires_in: 3600), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - result = Flow.new(provider: provider).refresh!( - server_url: @server_url, - resource_metadata_url: @prm_url, - ) - - assert_equal(:refreshed, result) - assert_equal("fresh-at", provider.access_token) - assert_nil(provider.client_information, "refresh must not persist a CIMD client_information entry") - end - - def test_refresh_raises_when_provider_has_cimd_url_but_as_no_longer_advertises_support - # If the AS later drops CIMD support and the provider has neither a stored `client_information` nor - # an alternative identity, refresh has no way to authenticate. Fail loudly rather than send a CIMD - # `client_id` the AS no longer recognises. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - assert_match(/client_id_metadata_document_supported/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_prefers_stored_client_information_over_cimd_url - # Even when both are available, an explicitly stored `client_information` wins. - # CIMD MUST NOT silently override it. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: true, - ), - ) - stub_request(:post, "#{@auth_base}/token").with( - body: hash_including( - "grant_type" => "refresh_token", - "client_id" => "preregistered-client", - ), - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer", expires_in: 3600), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - provider.save_client_information("client_id" => "preregistered-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - assert_equal("fresh-at", provider.access_token) - end - - def test_refresh_raises_when_cimd_support_advertised_as_string_true - # Mirror of the `run!` strict-boolean tests on the refresh path: a truthy non-boolean value - # such as the string `"true"` must NOT be treated as CIMD support. With no stored `client_information` - # and no genuine CIMD support, refresh has no identity to authenticate with. - stub_request(:get, @as_metadata_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - client_id_metadata_document_supported: "true", - ), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - assert_match(/client_id_metadata_document_supported/, error.message) - assert_not_requested(:post, "#{@auth_base}/token") - end - - def test_refresh_raises_when_no_refresh_token - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "only-at") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - end - - def test_refresh_raises_when_token_endpoint_rejects_refresh - stub_request(:post, "#{@auth_base}/token").to_return(status: 401, body: "") - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "revoked-rt") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - end - - def test_refresh_raises_invalid_grant_error_when_token_endpoint_says_invalid_grant - stub_request(:post, "#{@auth_base}/token").to_return( - status: 400, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(error: "invalid_grant", error_description: "refresh token expired"), - ) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "revoked-rt") - - error = assert_raises(Flow::InvalidGrantError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - assert_equal(400, error.http_status) - assert_equal("invalid_grant", error.error) - assert_equal("refresh token expired", error.error_description) - assert_equal("Token endpoint returned status 400. invalid_grant: refresh token expired", error.message) - end - - def test_token_exchange_preserves_oauth_diagnostics - stub_request(:post, "#{@auth_base}/token").to_return( - status: 400, - body: JSON.generate( - error: "invalid_request", - error_description: "Client must not use multiple authentication methods", - access_token: "do-not-log-access-token", - refresh_token: "do-not-log-refresh-token", - client_secret: "do-not-log-client-secret", - error_uri: "https://auth.example.com/error?secret=do-not-log", - ), - ) - - error = assert_raises(Flow::AuthorizationError) do - capture_authorization_scope(grant_types: ["authorization_code"]) - end - - assert_equal(400, error.http_status) - assert_equal("invalid_request", error.error) - assert_equal("Client must not use multiple authentication methods", error.error_description) - assert_equal( - "Token endpoint returned status 400. invalid_request: Client must not use multiple authentication methods", - error.message, - ) - end - - def test_refresh_preserves_oauth_diagnostics - error = refresh_token_endpoint_error( - JSON.generate(error: "invalid_client", error_description: "Client authentication failed"), - status: 401, - ) - - assert_instance_of(Flow::AuthorizationError, error) - assert_equal(401, error.http_status) - assert_equal("invalid_client", error.error) - assert_equal("Client authentication failed", error.error_description) - assert_equal("Token endpoint returned status 401. invalid_client: Client authentication failed", error.message) - end - - def test_token_endpoint_errors_fall_back_for_malformed_bodies - ["", "secret", "{broken", "null", "[]", '"secret"', "42"].each do |body| - error = refresh_token_endpoint_error(body) - - assert_instance_of(Flow::AuthorizationError, error) - assert_equal(400, error.http_status) - assert_nil(error.error) - assert_nil(error.error_description) - assert_equal("Token endpoint returned status 400.", error.message) - end - end - - def test_token_endpoint_errors_ignore_non_string_and_empty_fields - [nil, 42, true, [], { secret: "hidden" }, "", " \r\n\t"].each do |value| - error = refresh_token_endpoint_error(JSON.generate(error: value, error_description: value)) - - assert_nil(error.error) - assert_nil(error.error_description) - assert_equal("Token endpoint returned status 400.", error.message) - end - end - - def test_token_endpoint_errors_preserve_optional_fields_independently - error = refresh_token_endpoint_error(JSON.generate(error: "provider_extension")) - assert_equal("provider_extension", error.error) - assert_nil(error.error_description) - assert_equal("Token endpoint returned status 400. provider_extension", error.message) - - error = refresh_token_endpoint_error(JSON.generate(error_description: "Details without a code")) - assert_nil(error.error) - assert_equal("Details without a code", error.error_description) - assert_equal("Token endpoint returned status 400. Details without a code", error.message) - end - - def test_token_endpoint_errors_sanitize_without_changing_grant_classification - error = refresh_token_endpoint_error( - JSON.generate(error: "invalid_grant\n", error_description: "expired\r\n\t\e\u0000\"\\\u2028token"), - ) - - assert_instance_of(Flow::AuthorizationError, error) - assert_equal("invalid_grant", error.error) - assert_equal("expired token", error.error_description) - assert_equal("Token endpoint returned status 400. invalid_grant: expired token", error.message) - end - - def test_invalid_grant_with_invalid_utf8_description_preserves_classification - error = refresh_token_endpoint_error( - "{\"error\":\"invalid_grant\",\"error_description\":\"bad \xFF byte\"}".b, - ) - - assert_instance_of(Flow::InvalidGrantError, error) - assert_equal(400, error.http_status) - assert_equal("invalid_grant", error.error) - assert_equal("bad byte", error.error_description) - assert_equal("Token endpoint returned status 400. invalid_grant: bad byte", error.message) - end - - def test_token_endpoint_errors_scrub_invalid_utf8_in_both_fields - error = refresh_token_endpoint_error( - "{\"error\":\"invalid_grant\xFF\",\"error_description\":\"bad \xFF byte\"}".b, - ) - - assert_instance_of(Flow::AuthorizationError, error) - assert_equal(400, error.http_status) - assert_equal("invalid_grant", error.error) - assert_equal("bad byte", error.error_description) - assert_equal("Token endpoint returned status 400. invalid_grant: bad byte", error.message) - end - - def test_token_endpoint_errors_fall_back_when_diagnostic_extraction_raises - Flow.any_instance.stubs(:bounded_diagnostic).raises(ArgumentError, "sensitive provider text") - - { "invalid_grant" => Flow::InvalidGrantError, "invalid_client" => Flow::AuthorizationError }.each do |code, klass| - error = refresh_token_endpoint_error(JSON.generate(error: code, error_description: "details")) - - assert_instance_of(klass, error) - assert_equal(400, error.http_status) - assert_nil(error.error) - assert_nil(error.error_description) - assert_equal("Token endpoint returned status 400.", error.message) - end - end - - def test_token_endpoint_errors_bound_diagnostic_lengths - error = refresh_token_endpoint_error(JSON.generate(error: "e" * 200, error_description: "d" * 1000)) - - assert_equal("#{"e" * 125}...", error.error) - assert_equal("#{"d" * 509}...", error.error_description) - assert_equal("Token endpoint returned status 400. #{error.error}: #{error.error_description}", error.message) - end - - def test_other_authorization_errors_have_no_token_endpoint_diagnostics - error = Flow::AuthorizationError.new("Discovery failed") - - assert_equal("Discovery failed", error.message) - assert_nil(error.http_status) - assert_nil(error.error) - assert_nil(error.error_description) - end - - def refresh_token_endpoint_error(body, status: 400) - stub_request(:post, "#{@auth_base}/token").to_return(status: status, body: body) - provider = ssrf_test_provider - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "saved-rt") - - assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - end - - def test_refresh_raises_generic_authorization_error_on_5xx - stub_request(:post, "#{@auth_base}/token").to_return(status: 503, body: "") - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-at", "refresh_token" => "live-rt") - - err = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - end - refute_kind_of( - Flow::InvalidGrantError, - err, - "5xx must not be classified as invalid_grant; transient failures must preserve the refresh token", - ) - end - - def test_resolve_scope_prefers_prm_scopes_supported_over_provider_scope - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - scopes_supported: ["mcp:read", "mcp:write"], - ), - ) - - captured = nil - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - scope: "provider-supplied-scope", - redirect_handler: ->(url) { captured = url }, - callback_handler: -> { - [ - "code-1", - URI.decode_www_form(captured.query).to_h["state"], - ] - }, - ) - - Flow.new(provider: provider).run!( - server_url: @server_url, - resource_metadata_url: @prm_url, - scope: nil, - ) - - authorized_params = URI.decode_www_form(captured.query).to_h - assert_equal( - "mcp:read mcp:write", - authorized_params["scope"], - "PRM scopes_supported must win over provider.scope when challenge scope is absent", - ) - end - - def test_resolve_scope_falls_back_to_provider_scope_when_prm_omits_scopes_supported - captured = nil - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - scope: "provider-fallback", - redirect_handler: ->(url) { captured = url }, - callback_handler: -> { - [ - "code-1", - URI.decode_www_form(captured.query).to_h["state"], - ] - }, - ) - - Flow.new(provider: provider).run!( - server_url: @server_url, - resource_metadata_url: @prm_url, - scope: nil, - ) - - authorized_params = URI.decode_www_form(captured.query).to_h - assert_equal( - "provider-fallback", - authorized_params["scope"], - "provider.scope is the last-resort fallback when neither challenge nor PRM supplies one", - ) - end - - def test_token_endpoint_defaults_to_client_secret_basic_for_confidential_clients - captured_authorization = nil - captured_form = nil - stub_request(:post, "#{@auth_base}/token").to_return do |req| - captured_authorization = req.headers["Authorization"] - captured_form = URI.decode_www_form(req.body).to_h - { - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "tok", token_type: "Bearer"), - } - end - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - # Confidential pre-registered client without `token_endpoint_auth_method`. - provider.save_client_information( - "client_id" => "preregistered", - "client_secret" => "s3cret", - ) - provider.save_tokens("access_token" => "stale", "refresh_token" => "live-rt") - - Flow.new(provider: provider).refresh!(server_url: @server_url, resource_metadata_url: @prm_url) - - expected = Base64.strict_encode64("preregistered:s3cret") - assert_equal( - "Basic #{expected}", - captured_authorization, - "default to client_secret_basic per RFC 6749 §2.3.1 and TS/Python SDK convention", - ) - refute( - captured_form.key?("client_secret"), - "client_secret must not be duplicated in the form when sent via Basic auth", - ) - end - - def test_run_blocks_percent_encoded_dot_segment_bypass_in_server_url - # Same audience-binding bypass as the literal `..` case, but using - # the percent-encoded form `%2e%2e`. RFC 3986 Section 6.2.2.2 normalization must - # decode `%2e`/`%2E` before resolving dot-segments. - stub_request(:get, "https://srv.example.com/api/%2e%2e/evil/.well-known/oauth-protected-resource") - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/api", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!( - server_url: "https://srv.example.com/api/%2e%2e/evil", - resource_metadata_url: "https://srv.example.com/api/%2e%2e/evil/.well-known/oauth-protected-resource", - ) - end - - assert_match(/resource/i, error.message) - end - - def test_run_blocks_dot_segment_bypass_in_server_url - # An attacker-supplied server URL like "/api/../evil" must not be - # treated as covered by a PRM whose resource is the more privileged - # "/api". Canonicalization resolves the dot-segments so the bypass - # is detected. - stub_request(:get, "https://srv.example.com/api/../evil/.well-known/oauth-protected-resource") - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/api", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!( - server_url: "https://srv.example.com/api/../evil", - resource_metadata_url: "https://srv.example.com/api/../evil/.well-known/oauth-protected-resource", - ) - end - - assert_match(/resource/i, error.message) - end - - def test_run_strips_userinfo_from_resource_parameter_when_server_url_carries_credentials - # `Discovery.canonicalize_url` drops `user:pass@`, so the RFC 8707 - # `resource` parameter sent on both the authorization request and - # the token exchange must contain only the origin + path: shipping - # the raw URL would hand the user's credentials to the authorization - # server. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(authorization_servers: [@auth_base]), - ) - - captured_url = nil - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { captured_url = url }, - callback_handler: -> { - [ - "test-auth-code", - URI.decode_www_form(captured_url.query).to_h.fetch("state"), - ] - }, - ) - - Flow.new(provider: provider).run!( - server_url: "https://hunter2:t0psecret@srv.example.com/mcp", - resource_metadata_url: @prm_url, - ) - - query = URI.decode_www_form(captured_url.query).to_h - assert_equal("https://srv.example.com/mcp", query["resource"]) - refute_includes(query["resource"], "hunter2") - refute_includes(query["resource"], "t0psecret") - - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - form["resource"] == "https://srv.example.com/mcp" - end - end - - def test_run_resource_mismatch_error_does_not_leak_userinfo - # When PRM advertises a `resource` that does not cover the MCP server - # URL, the mismatch error message MUST cite the canonicalized URLs so - # that `user:pass@` cannot reach logs, stack traces, or exception - # reporters. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://hunter2:t0psecret@evil.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!( - server_url: "https://hunter2:t0psecret@srv.example.com/mcp", - resource_metadata_url: @prm_url, - ) - end - - refute_includes(error.message, "hunter2") - refute_includes(error.message, "t0psecret") - end - - def test_run_blocks_cross_tenant_query_bypass - # A hijacked PRM that advertises a different tenant's `resource` - # MUST cause an audience-binding failure rather than allowing - # the client to mint a token bound to the attacker's tenant for - # the victim's MCP server. - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp?tenant=evil", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!( - server_url: "https://srv.example.com/mcp?tenant=victim", - resource_metadata_url: @prm_url, - ) - end - - assert_match(/resource/i, error.message) - end - - def test_run_raises_on_resource_mismatch - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://evil.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - error = assert_raises(Flow::AuthorizationError) do - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - end - - assert_match(/resource/i, error.message) - end - - def test_run_sends_server_url_as_resource_when_prm_omits_it - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(authorization_servers: [@auth_base]), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:url] = url - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - Flow.new(provider: provider).run!(server_url: @server_url, resource_metadata_url: @prm_url) - - query = URI.decode_www_form(state_holder[:url].query).to_h - assert_equal("https://srv.example.com/mcp", query["resource"]) - - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["resource"] == "https://srv.example.com/mcp" - end - end - - private - - def refresh_only_provider - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - provider.save_client_information("client_id" => "test-client") - - provider - end - end - end - end -end diff --git a/test/mcp/client/oauth/http_oauth_test.rb b/test/mcp/client/oauth/http_oauth_test.rb deleted file mode 100644 index dcbe302..0000000 --- a/test/mcp/client/oauth/http_oauth_test.rb +++ /dev/null @@ -1,1946 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "json" -require "webmock/minitest" -require "faraday" -require "mcp/client/http" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class HTTPOAuthTest < Minitest::Test - # Records `[method, url]` for every request that passes through, standing in for the tracing - # middleware an application adds through `http_client_customizer`. - class RecordingMiddleware - def initialize(app, log) - @app = app - @log = log - end - - def call(env) - @log << [env.method, env.url.to_s] - @app.call(env) - end - end - - # Sends the request for `from` to `to` instead, the shape redirect-following middleware leaves behind. - class URLRewritingMiddleware - def initialize(app, from:, to:) - @app = app - @from = from - @to = to - end - - def call(env) - env.url = URI(@to) if env.url.to_s == @from - @app.call(env) - end - end - - # Hands the next middleware an environment rebuilt from Faraday's own members only, dropping whatever - # an earlier middleware recorded on the original. - class EnvRebuildingMiddleware - def initialize(app) - @app = app - end - - def call(env) - @app.call(Faraday::Env.from(env.to_h)) - end - end - - def setup - WebMock.enable! - @mcp_url = "https://srv.example.com/mcp" - @prm_url = "https://srv.example.com/.well-known/oauth-protected-resource/mcp" - @auth_base = "https://auth.example.com" - end - - def teardown - WebMock.reset! - end - - def test_send_request_runs_oauth_flow_on_401_and_retries_with_bearer_token - # First POST: 401 with WWW-Authenticate. Second POST (with Bearer): 200. - stub_request(:post, @mcp_url) - .with { |req| req.headers["Authorization"].nil? } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer test-token-after-flow" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "test-token-after-flow", token_type: "Bearer", expires_in: 3600), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal("test-token-after-flow", provider.access_token) - end - - def test_send_request_runs_the_oauth_flow_through_the_provider_customizer - stub_request(:post, @mcp_url).with { |req| - req.headers["Authorization"].nil? - }.to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer test-token-after-flow" } - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "test-token-after-flow", token_type: "Bearer", expires_in: 3600), - ) - - log = [] - state_holder = {} - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - http_client_customizer: ->(faraday) { faraday.use(RecordingMiddleware, log) }, - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal( - [ - [:get, @prm_url], - [:get, "#{@auth_base}/.well-known/oauth-authorization-server"], - [:post, "#{@auth_base}/register"], - [:post, "#{@auth_base}/token"], - ], - log, - ) - end - - def test_send_request_does_not_follow_a_resource_metadata_challenge_off_the_server_origin - # End to end over the transport, which is where the header is actually parsed: - # a server that answers 401 must not be able to name an unrelated host in - # `resource_metadata` and have the client fetch it. The request never leaving - # is the point; the 401 surfacing to the caller is secondary. - metadata_url = "https://169.254.169.254/latest/meta-data/iam/" - - stub_request(:post, @mcp_url).to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{metadata_url}"), - }, - body: "", - ) - stub_request(:get, metadata_url).to_return(status: 200, body: "{}") - - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - assert_raises(StandardError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - - assert_not_requested(:get, metadata_url) - end - - def test_send_request_runs_step_up_flow_on_403_insufficient_scope - # First call with the initial token: 403 carrying an `insufficient_scope` - # Bearer challenge with the escalated scope. The transport must re-run - # a full authorization (NOT a refresh) with the escalated scope and - # retry the original request. - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer initial-token" }, - ).to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:basic mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer escalated-token" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_step_up_authorization_server - provider = build_step_up_provider - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: { name: "x" } }, - ) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal("escalated-token", provider.access_token) - - # The fresh authorization-code grant ran (refresh path was bypassed). - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - form["grant_type"] == "authorization_code" && - form["code"] == "test-auth-code" - end - - # And the authorization request the SDK handed to the redirect - # handler carried the escalated scope from the challenge. - authorization_query = URI.decode_www_form(provider.last_authorization_url.query).to_h - assert_equal("mcp:basic mcp:write", authorization_query["scope"]) - end - - def test_send_request_step_up_unions_existing_scope_with_challenge_scope - # MCP step-up: the re-authorization request must ask for the union - # of the previously granted scope and the newly demanded scope. - # Otherwise the new token would lack permissions the caller had - # before, triggering another step-up the next time they are used. - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer initial-token" }) - .to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer escalated-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_step_up_authorization_server - provider = build_step_up_provider - # The provider already holds a token granted for `mcp:read`. - provider.save_tokens( - "access_token" => "initial-token", - "token_type" => "Bearer", - "scope" => "mcp:read", - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - authorization_query = URI.decode_www_form(provider.last_authorization_url.query).to_h - requested = authorization_query["scope"].split - assert_includes(requested, "mcp:read", "must preserve previously granted scope") - assert_includes(requested, "mcp:write", "must add the newly demanded scope") - assert_equal(requested.uniq.length, requested.length, "must not duplicate scopes") - end - - def test_send_request_does_not_retry_plain_403 - # A 403 without an `insufficient_scope` Bearer challenge is a hard - # forbidden, not a step-up signal. Surface it as a `RequestHandlerError` - # rather than tripping the OAuth flow. - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer initial-token" }, - ).to_return( - status: 403, body: "", - ) - - provider = build_step_up_provider - transport = HTTP.new(url: @mcp_url, oauth: provider) - - error = assert_raises(MCP::Client::RequestHandlerError) do - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - end - assert_equal(:forbidden, error.error_type) - assert_not_requested(:get, "#{@auth_base}/.well-known/oauth-authorization-server") - end - - def test_send_request_does_not_loop_on_repeated_insufficient_scope - # The server keeps demanding more scope after every authorization. - # The transport retries the step-up flow at most once per - # `send_request`, then surfaces the 403 to the caller. - stub_request(:post, @mcp_url).to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:everything", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_step_up_authorization_server - provider = build_step_up_provider - transport = HTTP.new(url: @mcp_url, oauth: provider) - - error = assert_raises(MCP::Client::RequestHandlerError) do - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - end - assert_equal(:forbidden, error.error_type) - end - - def test_send_request_step_up_bypasses_refresh_token - # The provider has a refresh_token, but step-up MUST run a fresh - # authorization request with the escalated scope, not exchange the - # refresh_token. Refreshing would mint a new access token with the - # same scopes as the current one, which already failed. - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer initial-token" }, - ).to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:basic mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer escalated-token" }, - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_step_up_authorization_server - provider = build_step_up_provider - provider.save_tokens( - "access_token" => "initial-token", - "refresh_token" => "saved-rt", - "token_type" => "Bearer", - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - # The token endpoint was only called for the fresh - # `authorization_code` grant, never for `refresh_token`. - assert_not_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["grant_type"] == "refresh_token" - end - end - - def test_send_request_step_up_appends_offline_access_when_advertised - # Integration of step-up with the SEP-2207 offline_access logic: - # the re-authorization request unions the existing and challenge scopes, - # then -- because the AS advertises `offline_access` and the client - # declared the `refresh_token` grant -- `offline_access` is appended - # so the escalated token can itself be refreshed later. - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer initial-token" }) - .to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer escalated-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_step_up_authorization_server( - extra_as_metadata: { scopes_supported: ["mcp:read", "mcp:write", "offline_access"] }, - ) - provider = build_step_up_provider(grant_types: ["authorization_code", "refresh_token"]) - provider.save_tokens( - "access_token" => "initial-token", - "token_type" => "Bearer", - "scope" => "mcp:read", - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - requested = URI.decode_www_form(provider.last_authorization_url.query).to_h["scope"].split - assert_includes(requested, "mcp:read", "must preserve previously granted scope") - assert_includes(requested, "mcp:write", "must add the challenged scope") - assert_includes(requested, "offline_access", "must append offline_access when advertised") - end - - def test_send_request_step_up_strips_offline_access_when_not_advertised - # Mirror of the previous test: if the AS does NOT advertise - # `offline_access`, the step-up request must not carry it even when - # the existing token's scope happened to include it - # (SEP-2207 MUST-NOT, enforced by `normalize_offline_access_scope`). - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer initial-token" }) - .to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer escalated-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - # AS advertises only resource scopes, no offline_access. - stub_step_up_authorization_server( - extra_as_metadata: { scopes_supported: ["mcp:read", "mcp:write"] }, - ) - provider = build_step_up_provider(grant_types: ["authorization_code", "refresh_token"]) - provider.save_tokens( - "access_token" => "initial-token", - "token_type" => "Bearer", - "scope" => "mcp:read offline_access", - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - requested = URI.decode_www_form(provider.last_authorization_url.query).to_h["scope"].split - assert_includes(requested, "mcp:read") - assert_includes(requested, "mcp:write") - refute_includes(requested, "offline_access", "must strip offline_access when the AS does not advertise it") - end - - def test_send_request_step_up_uses_cimd_client_id - # Integration of step-up with Client ID Metadata Documents: - # when the provider is CIMD-configured and the AS advertises CIMD support, - # the step-up re-authorization uses the CIMD URL as `client_id` and skips - # Dynamic Client Registration, just like the initial flow. - cimd_url = "https://app.example.com/client-metadata.json" - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer initial-token" }) - .to_return( - status: 403, - headers: { - "WWW-Authenticate" => %(Bearer error="insufficient_scope", ) + - %(scope="mcp:basic mcp:write", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer escalated-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_step_up_authorization_server( - extra_as_metadata: { client_id_metadata_document_supported: true }, - ) - provider = build_step_up_provider(client_id_metadata_document_url: cimd_url) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - transport.send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - # DCR was skipped and the CIMD URL was used as the client_id on - # the escalated authorization request. - assert_not_requested(:post, "#{@auth_base}/register") - authorization_query = URI.decode_www_form(provider.last_authorization_url.query).to_h - assert_equal(cimd_url, authorization_query["client_id"]) - end - - def test_initialize_rejects_non_secure_mcp_url_when_oauth_is_set - # A bearer token sent to `http://attacker.example.com/mcp` would leak - # over the wire. When OAuth is on, the transport URL must clear - # the same Communication Security bar as every other OAuth-related URL. - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - MCP::Client::HTTP.new(url: "http://attacker.example.com/mcp", oauth: provider) - end - end - - def test_initialize_allows_loopback_http_mcp_url_when_oauth_is_set - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - ) - - # Loopback HTTP is permitted for local development / conformance. - MCP::Client::HTTP.new(url: "http://localhost:9292/mcp", oauth: provider) - MCP::Client::HTTP.new(url: "http://127.0.0.1:9292/mcp", oauth: provider) - end - - def test_initialize_allows_non_secure_mcp_url_when_oauth_is_nil - # Without OAuth, no bearer tokens are sent, so the SDK leaves - # the scheme decision to the caller. - MCP::Client::HTTP.new(url: "http://internal.example.com/mcp") - end - - def test_refresh_path_preserves_query_string_in_resource_claim - # The refresh flow MUST send the same canonical `resource` claim as - # the original authorization request -- otherwise the AS rejects - # the refresh as a different audience. Verify by giving the transport - # a query-bearing MCP URL and a saved refresh token, then asserting - # the refresh POST body carries the full URL. - tenant_mcp_url = "https://srv.example.com/mcp?tenant=1" - - stub_request(:post, tenant_mcp_url) - .with { |req| req.headers["Authorization"] != "Bearer refreshed-tenant-token" } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, tenant_mcp_url) - .with(headers: { "Authorization" => "Bearer refreshed-tenant-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "refreshed-tenant-token", token_type: "Bearer", expires_in: 3600), - ) - - provider = build_provider - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale", "refresh_token" => "valid-rt") - - transport = HTTP.new(url: tenant_mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - - # The refresh POST body's `resource` MUST keep the query string so it - # matches the audience the original token was minted for. - assert_requested(:post, "#{@auth_base}/token") do |req| - form = URI.decode_www_form(req.body).to_h - form["grant_type"] == "refresh_token" && - form["resource"] == "https://srv.example.com/mcp?tenant=1" - end - end - - def test_send_request_refreshes_when_refresh_token_is_available - # On 401 with a saved refresh_token, the transport should swap it for - # a fresh access token rather than re-running the full interactive - # Authorization Code flow. - stub_request(:post, @mcp_url) - .with { |req| req.headers["Authorization"] != "Bearer refreshed-token" } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer refreshed-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - # DCR and /authorize must not be invoked when refresh succeeds. - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - stub_request(:get, "#{@auth_base}/authorize").to_raise(StandardError.new("authorize should not be called.")) - - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "refreshed-token", token_type: "Bearer", expires_in: 3600), - ) - - provider = build_provider - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-token", "refresh_token" => "saved-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal("refreshed-token", provider.access_token) - end - - def test_send_request_refreshes_for_a_cross_app_access_provider_holding_a_refresh_token - # Refresh serves every provider, not only the authorization-code one that has a CIMD URL reader. - stub_request(:post, @mcp_url).with { |req| - req.headers["Authorization"] != "Bearer refreshed-token" - }.to_return( - status: 401, - headers: { "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}") }, - body: "", - ) - - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer refreshed-token" } - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - token_endpoint: "#{@auth_base}/token", - grant_types_supported: ["urn:ietf:params:oauth:grant-type:jwt-bearer", "refresh_token"], - token_endpoint_auth_methods_supported: ["client_secret_basic"], - ), - ) - - stub_request(:post, "#{@auth_base}/token").with( - body: hash_including("grant_type" => "refresh_token", "refresh_token" => "saved-rt") - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "refreshed-token", token_type: "Bearer", expires_in: 3600), - ) - - assertion_calls = 0 - provider = CrossAppAccessProvider.new( - client_id: "xaa-client", - client_secret: "xaa-secret", - assertion_provider: ->(**) { - assertion_calls += 1 - "id-jag-assertion" - }, - ) - provider.save_tokens("access_token" => "stale-token", "refresh_token" => "saved-rt", "issuer" => @auth_base) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal("refreshed-token", provider.access_token) - assert_equal(0, assertion_calls) - end - - def test_send_request_surfaces_a_bad_token_request_params_hook_instead_of_reauthorizing - # A provider whose `token_request_params` names a reserved key is misconfigured, not unauthorized: - # the refresh attempt must raise rather than fall through to the interactive flow, - # which would fail the same way after the user signed in. - stub_request(:post, @mcp_url).to_return( - status: 401, - headers: { "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}") }, - body: "", - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - redirected = false - provider_class = Class.new(Provider) do - define_method(:token_request_params) { { "grant_type" => "password" } } - end - provider = provider_class.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) { redirected = true }, - callback_handler: -> { ["code", "state"] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-token", "refresh_token" => "saved-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - assert_raises(Flow::InvalidTokenRequestParamsError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - refute(redirected) - assert_not_requested(:post, "#{@auth_base}/token") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_send_request_surfaces_a_refused_refresh_without_falling_back - # A customizer middleware that would carry the refresh request off the origin is refused before - # the request leaves, and that refusal is not one of the failures that start the interactive flow - # or discard the stored tokens. - stub_request(:post, @mcp_url).to_return( - status: 401, - headers: { "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}") }, - body: "", - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - stub_request(:post, "https://other.example.com/token").to_raise(StandardError.new("the rewritten request must not leave.")) - - provider = build_provider( - http_client_customizer: ->(faraday) { - faraday.use(URLRewritingMiddleware, from: "#{@auth_base}/token", to: "https://other.example.com/token") - }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-token", "refresh_token" => "saved-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - assert_raises(MCP::Client::OAuth::Flow::DestinationMismatchError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - - assert_not_requested(:post, "https://other.example.com/token") - assert_not_requested(:post, "#{@auth_base}/token") - assert_not_requested(:post, "#{@auth_base}/register") - assert_equal("saved-rt", provider.tokens["refresh_token"]) - end - - def test_send_request_surfaces_a_refresh_whose_environment_was_rebuilt_without_falling_back - # The missing-record refusal takes the same route as the origin mismatch: out of `send_request`, - # with no interactive fallback and the stored tokens intact. - stub_request(:post, @mcp_url).to_return( - status: 401, - headers: { "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}") }, - body: "", - ) - stub_request(:get, @prm_url).to_raise(StandardError.new("the rebuilt request must not leave.")) - stub_request(:post, "#{@auth_base}/register").to_raise(StandardError.new("DCR should not be called.")) - - interactive_flow_started = false - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) { interactive_flow_started = true }, - callback_handler: -> { ["code", "state"] }, - http_client_customizer: ->(faraday) { faraday.use(EnvRebuildingMiddleware) }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale-token", "refresh_token" => "saved-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - error = assert_raises(MCP::Client::OAuth::Flow::DestinationMismatchError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - - assert_match(/carries no record of the URL the flow asked for/, error.message) - refute(interactive_flow_started, "the refusal must not fall back to the interactive flow") - assert_not_requested(:get, @prm_url) - assert_not_requested(:post, "#{@auth_base}/token") - assert_not_requested(:post, "#{@auth_base}/register") - assert_equal({ "access_token" => "stale-token", "refresh_token" => "saved-rt" }, provider.tokens) - end - - def test_send_request_preserves_refresh_token_when_refresh_hits_a_transient_failure - # A 5xx (or any non-`invalid_grant`) from the token endpoint indicates - # a transient AS outage, NOT that the refresh token is dead. - # The transport must fall through to the full Authorization Code flow - # (we cannot serve the MCP request without a fresh access token), but - # the stored refresh_token must remain so subsequent attempts on - # the next outage-free request can succeed without interactive reauth. - stub_request(:post, @mcp_url) - .with { |req| req.headers["Authorization"] != "Bearer brand-new-token" } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer brand-new-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - # Refresh request: transient 503. Auth code exchange: succeeds with - # a NEW refresh token (so we can prove the live RT survived rather than - # being silently overwritten by the success path). - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token")) - .to_return(status: 503, body: "") - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "authorization_code")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "brand-new-token", token_type: "Bearer"), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale", "refresh_token" => "live-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - # The transient 503 must not wipe the refresh token; the auth-code - # success path overwrites tokens, but we asserted the prior refresh - # token survived the refresh-attempt failure by NOT seeing the full - # flow trigger `clear_tokens!`. To prove this, inspect that - # the final stored refresh_token is whatever the auth-code response - # provided (omitted here), not nil from a forced clear. - stored = provider.tokens || {} - assert_equal("brand-new-token", stored["access_token"] || stored[:access_token]) - end - - def test_send_request_falls_back_to_full_flow_when_refresh_fails - # If the refresh request itself is rejected (refresh token revoked), - # the transport should clear stale tokens and fall through to - # the full Authorization Code flow. - stub_request(:post, @mcp_url) - .with { |req| req.headers["Authorization"] != "Bearer brand-new-token" } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer brand-new-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: "https://srv.example.com/mcp", authorization_servers: [@auth_base]), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - # First /token call (refresh) fails; second call (authorization_code) succeeds. - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "refresh_token")) - .to_return(status: 401, body: "") - stub_request(:post, "#{@auth_base}/token") - .with(body: hash_including("grant_type" => "authorization_code")) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "brand-new-token", token_type: "Bearer", expires_in: 3600), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - provider.save_client_information("client_id" => "test-client") - provider.save_tokens("access_token" => "stale", "refresh_token" => "revoked-rt") - - transport = HTTP.new(url: @mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - assert_equal("brand-new-token", provider.access_token) - end - - def test_oauth_flow_preserves_query_string_in_resource_claim - # Query parameters on the MCP URL (e.g. `?tenant=...`) must be carried - # into the RFC 8707 `resource` claim sent on the authorization and - # token requests, matching how the TS and Python SDKs build - # the canonical resource URL. The URL guard's snapshot is allowed to drop - # the query because Faraday does the same at request time, but - # the OAuth-side snapshot must retain it. - tenant_mcp_url = "https://srv.example.com/mcp?tenant=1" - - stub_request(:post, tenant_mcp_url) - .with { |req| req.headers["Authorization"].nil? } - .to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:post, tenant_mcp_url) - .with(headers: { "Authorization" => "Bearer tenant-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - # PRM is allowed to omit `resource`; the client falls back to its - # canonical MCP URL (query and all). - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "tenant-token", token_type: "Bearer", expires_in: 3600), - ) - - captured_authorization_url = nil - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { captured_authorization_url = url }, - callback_handler: -> { - query = URI.decode_www_form(captured_authorization_url.query).to_h - ["test-auth-code", query.fetch("state")] - }, - ) - - transport = HTTP.new(url: tenant_mcp_url, oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - - # The authorization URL's `resource` parameter MUST keep the query. - query = URI.decode_www_form(captured_authorization_url.query).to_h - assert_equal("https://srv.example.com/mcp?tenant=1", query["resource"]) - - # The token endpoint POST body's `resource` MUST also keep the query. - assert_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["resource"] == "https://srv.example.com/mcp?tenant=1" - end - end - - def test_oauth_flow_uses_validated_url_after_url_mutation - # Even if an attacker mutates `@url` after construction (e.g. - # `instance_variable_set(:@url, "https://attacker.example.com/mcp")`), - # the OAuth discovery / authorization code flow MUST continue to use - # the URL snapshotted at initialize time. Otherwise PRM, AS metadata, - # and the `resource` claim sent to the authorization server would - # all point at the attacker-controlled host. - attacker_prm = "https://attacker.example.com/.well-known/oauth-protected-resource/mcp" - attacker_root_prm = "https://attacker.example.com/.well-known/oauth-protected-resource" - stub_request(:get, attacker_prm).to_raise(StandardError.new("PRM must not target attacker host.")) - stub_request(:get, attacker_root_prm).to_raise(StandardError.new("PRM must not target attacker host.")) - - stub_request(:post, @mcp_url) - .with { |req| req.headers["Authorization"] != "Bearer post-mutation-token" } - .to_return( - status: 401, - # No `resource_metadata` to force PRM derivation from - # the server_url -- this is exactly the path where a mutated - # `@url` could redirect discovery without the snapshot. - headers: { "WWW-Authenticate" => 'Bearer error="invalid_token"' }, - body: "", - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "post-mutation-token", token_type: "Bearer", expires_in: 3600), - ) - - captured_authorization_url = nil - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { captured_authorization_url = url }, - callback_handler: -> { - query = URI.decode_www_form(captured_authorization_url.query).to_h - ["test-auth-code", query.fetch("state")] - }, - ) - - stub_request(:post, @mcp_url) - .with(headers: { "Authorization" => "Bearer post-mutation-token" }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - # Force the lazy Faraday connection to be built against the validated - # URL before the mutation. After this, `@client.url_prefix` is - # locked to `srv.example.com` regardless of what `@url` later points - # at, which is what the URL guard middleware reads. - transport.send(:client) - transport.instance_variable_set(:@url, "https://attacker.example.com/mcp") - - # The first 401 must drive `run_oauth_flow!` against the validated - # URL, not the mutated `@url`. The OAuth flow succeeds, the retry - # carries the new bearer token, and Faraday (still pointed at - # the safe URL via its frozen `url_prefix`) returns the stubbed 200. - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - # Discovery must have aimed at the validated host. The attacker-host - # PRM stubs would have raised otherwise. - assert_requested(:get, @prm_url) - refute_requested(:get, attacker_prm) - refute_requested(:get, attacker_root_prm) - # The `resource` claim sent on the authorization URL is built from - # the validated URL, not the attacker-host mutation. - query = URI.decode_www_form(captured_authorization_url.query).to_h - assert_equal("https://srv.example.com/mcp", query["resource"]) - refute_includes(query["resource"], "attacker.example.com") - end - - def test_send_request_rejects_url_mutation_after_initialize - # The constructor secure-URL check alone is not enough: `@url` is - # a plain instance variable, so a caller can `instance_variable_set` it - # to a non-secure URL after the transport is built. The send-time - # re-check must catch this and refuse to send the bearer token. - provider = build_provider - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp", oauth: provider) - transport.instance_variable_set(:@url, "http://attacker.example.com/mcp") - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_rejects_faraday_customizer_url_swap - # An `&block` Faraday customizer can rewrite `url_prefix` to point at - # a plaintext attacker host; the constructor URL check would miss this. - # The send-time effective-URL check must reject it. - provider = build_provider - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp", oauth: provider) do |faraday| - faraday.url_prefix = "http://attacker.example.com/mcp" - end - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_rejects_https_to_different_host_via_customizer - # An `https://` URL alone is not enough - the URL must also match - # the one validated at initialize time. A customizer that swaps to - # a *different* https host (e.g. `https://attacker.example.com/mcp`) - # would otherwise pass a naive "still https?" check and leak - # the bearer token to the attacker. - provider = build_provider - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp", oauth: provider) do |faraday| - faraday.url_prefix = "https://attacker.example.com/mcp" - end - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_rejects_middleware_env_url_query_rewrite - # A Faraday middleware that swaps only the query (`tenant=victim` -> - # `tenant=evil`) must be caught by the URL guard. Otherwise - # an attacker who can inject middleware can ship the bearer token to - # a different tenant of the same origin/path while the OAuth-side - # audience binding stays correct. - rewrite_query_middleware = Class.new do - def initialize(app) - @app = app - end - - def call(env) - env.url.query = "tenant=evil" - @app.call(env) - end - end - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - transport = MCP::Client::HTTP.new( - url: "https://srv.example.com/mcp?tenant=victim", - oauth: provider, - ) do |faraday| - faraday.use(rewrite_query_middleware) - end - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_rejects_middleware_env_url_rewrite - # A Faraday middleware can mutate `env.url` at request time, which - # `Faraday::Connection#url_prefix` cannot detect. The identity guard - # must run as a middleware *after* the customizer so it sees - # the rewritten env.url before it reaches the adapter. - rewrite_middleware = Class.new do - def initialize(app) - @app = app - end - - def call(env) - env.url = URI("https://attacker.example.com/mcp") - @app.call(env) - end - end - - provider = build_provider - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp", oauth: provider) do |faraday| - faraday.use(rewrite_middleware) - end - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_accepts_validated_url_with_userinfo - # Faraday hoists `user:pass@` out of the URL into an `Authorization: - # Basic` header, so `env.url` at request time does not carry - # the userinfo. The identity guard must drop userinfo on both sides to - # avoid a false-positive `InsecureURLError` on this valid URL. - stub_request(:post, "https://srv.example.com/mcp") - .with(headers: { "Authorization" => /Basic|Bearer/ }) - .to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://user:pass@srv.example.com/mcp", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_insecure_url_error_does_not_leak_userinfo - # The error message MUST surface only the canonicalized (origin + path) - # form so that `user:pass@` cannot leak into logs, stack traces, or - # exception reporters. - provider = build_provider - error = assert_raises(MCP::Client::HTTP::InsecureURLError) do - MCP::Client::HTTP.new(url: "http://hunter2:t0psecret@attacker.example.com/mcp", oauth: provider) - end - - refute_includes(error.message, "hunter2") - refute_includes(error.message, "t0psecret") - end - - def test_send_request_accepts_validated_url_with_query_string - # A `?tenant=1` style query on the user-supplied URL must not trip - # the identity guard. `Faraday::Connection#url_prefix.to_s` drops - # the query, so naive string-compare would raise a false-positive - # `InsecureURLError` on the very first request. - stub_request(:post, "https://srv.example.com/mcp?tenant=1").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?tenant=1", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_unsorted_query_parameters - # Faraday sorts query parameters by name before sending the request, - # so the snapshot and the effective URL must compare as equal even - # when the user-supplied URL listed `b` first and `a` second. - stub_request(:post, "https://srv.example.com/mcp?b=2&a=1").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?b=2&a=1", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_lowercase_percent_encoded_hex - # Faraday uppercases percent-encoded hex digits (`%2f` -> `%2F`), - # so the snapshot and the effective URL must compare as equal even - # when the user-supplied URL used lowercase hex. - stub_request(:post, "https://srv.example.com/mcp?x=%2f").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?x=%2f", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_valueless_query_key - # `?tenant` (no `=`) and `?tenant=` (empty value) are distinct in - # Faraday's encoding. The snapshot must preserve that distinction - # so the URL guard does not false-positive when the user-supplied - # URL omits the `=`. - stub_request(:post, "https://srv.example.com/mcp?tenant").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?tenant", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_array_form_query_parameters - # Faraday preserves array-form (`?roles[]=a&roles[]=b`) duplicates - # rather than collapsing them. The snapshot must do the same so - # the URL guard does not raise a false positive. - stub_request(:post, "https://srv.example.com/mcp?roles[]=a&roles[]=b").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?roles[]=a&roles[]=b", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_rejects_array_form_query_entry_drop_via_middleware - # An attacker middleware that strips one value from a multi-value - # array-form query (`?tenant[]=victim&tenant[]=victim2` -> - # `?tenant[]=victim`) must be caught by the URL guard. If - # the snapshot collapsed duplicates, both forms would compare as equal - # and the bearer token would leak to a partially-rewritten audience. - drop_first_value_middleware = Class.new do - def initialize(app) - @app = app - end - - def call(env) - env.url.query = "tenant%5B%5D=victim" - @app.call(env) - end - end - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - transport = MCP::Client::HTTP.new( - url: "https://srv.example.com/mcp?tenant[]=victim&tenant[]=victim2", - oauth: provider, - ) do |faraday| - faraday.use(drop_first_value_middleware) - end - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_accepts_url_with_blank_query_segments - # Faraday's query encoder drops empty-name pairs and blank `&&` - # separators (`?&&a=1&&` -> `?a=1`). The snapshot must do the same - # so the URL guard does not raise a false positive. - stub_request(:post, "https://srv.example.com/mcp?a=1").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?&&a=1&&", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_repeated_query_parameters - # Faraday's query encoder collapses repeated same-name parameters - # to the last value (`?a=1&a=2` -> `?a=2`). The snapshot must apply - # the same collapse so the URL guard does not raise a false - # positive. - stub_request(:post, "https://srv.example.com/mcp?a=2").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?a=1&a=2", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_accepts_url_with_empty_query_marker - # Faraday drops a bare trailing `?` with no parameters, so - # the snapshot and the effective URL must compare as equal even when - # the user-supplied URL kept the `?` marker. - stub_request(:post, "https://srv.example.com/mcp").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - provider = build_provider - provider.save_tokens("access_token" => "valid-token") - - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp?", oauth: provider) - response = transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - - assert_equal({ "ok" => true }, response["result"]) - end - - def test_send_request_rejects_https_to_different_host_via_url_mutation - # Same identity-binding requirement when the swap goes through - # `instance_variable_set(:@url, ...)`: the new URL is HTTPS, but it - # is not the URL that was validated at initialize time. - stub_request(:post, "https://attacker.example.com/mcp").to_return(status: 200, body: "") - provider = build_provider - transport = MCP::Client::HTTP.new(url: "https://srv.example.com/mcp", oauth: provider) - transport.instance_variable_set(:@url, "https://attacker.example.com/mcp") - transport.instance_variable_set(:@client, nil) # force Faraday rebuild against mutated @url - - assert_raises(MCP::Client::HTTP::InsecureURLError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_raises_unauthorized_when_no_oauth_provider - stub_request(:post, @mcp_url).to_return(status: 401, body: "") - transport = HTTP.new(url: @mcp_url) - - error = assert_raises(MCP::Client::RequestHandlerError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - assert_equal(:unauthorized, error.error_type) - end - - def test_send_request_does_not_loop_when_oauth_flow_fails - stub_request(:post, @mcp_url).to_return(status: 401, body: "") - stub_request(:get, @prm_url).to_return(status: 404, body: "") - stub_request(:get, "https://srv.example.com/.well-known/oauth-protected-resource").to_return( - status: 404, - body: "", - ) - - # With no PRM, discovery falls back to the legacy 2025-03-26 path; dead-end that too so the flow fails exactly once. - stub_request(:get, "https://srv.example.com/.well-known/oauth-authorization-server").to_return(status: 404) - stub_request(:get, "https://srv.example.com/.well-known/openid-configuration").to_return(status: 404) - stub_request(:post, "https://srv.example.com/register").to_return(status: 404) - - provider = Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { [nil, nil] }, - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - assert_raises(Flow::AuthorizationError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - end - - def test_send_request_does_not_re_run_oauth_flow_on_repeated_401 - # Server keeps returning 401 even after a successful token exchange. - # The retry guard MUST limit OAuth flow execution to one attempt per - # `send_request` so we surface the failure instead of looping. - stub_request(:post, @mcp_url).to_return( - status: 401, - headers: { - "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}"), - }, - body: "", - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "still-bad-token", token_type: "Bearer", expires_in: 3600), - ) - - state_holder = {} - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - ) - - transport = HTTP.new(url: @mcp_url, oauth: provider) - - assert_raises(MCP::Client::RequestHandlerError) do - transport.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" }) - end - - # Token endpoint should be hit at most once across the failing call, - # proving the retry guard prevents an infinite re-authorization loop. - assert_requested(:post, "#{@auth_base}/token", times: 1) - end - - def test_send_request_reauthorizes_when_the_authorization_server_did_not_issue_the_stored_tokens - # The refusal in `refresh!` is only half the answer; this is the other half. - # A renamed authorization server makes the refresh fail, the transport falls through to a full authorization, - # and that is where the embedding application is asked about the new one. - stub_request(:post, @mcp_url).with { |req| - req.headers["Authorization"] != "Bearer fresh-at" - }.to_return( - status: 401, - headers: { "WWW-Authenticate" => %(Bearer error="invalid_token", resource_metadata="#{@prm_url}") }, - body: "", - ) - stub_request(:post, @mcp_url).with( - headers: { "Authorization" => "Bearer fresh-at" } - ).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(jsonrpc: "2.0", id: "1", result: { ok: true }), - ) - - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(resource: @mcp_url, authorization_servers: [@auth_base]), - ) - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - ), - ) - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "reauthorized-client"), - ) - stub_request(:post, "#{@auth_base}/token").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(access_token: "fresh-at", token_type: "Bearer"), - ) - - seen = [] - state_holder = {} - provider = Provider.new( - client_metadata: { - redirect_uris: ["http://localhost:0/callback"], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - authorization_request_validator: ->(request) { - seen << request.authorization_server - true - }, - ) - - # Registered and refreshable, so the refresh path is genuinely reachable and the issuer binding is - # what stops it rather than a missing client identity. - provider.save_client_information("client_id" => "test-client") - provider.save_tokens( - "access_token" => "stale-at", - "refresh_token" => "saved-rt", - "issuer" => "https://issued-by.example.com", - ) - - HTTP.new(url: @mcp_url, oauth: provider).send_request( - request: { jsonrpc: "2.0", id: "1", method: "tools/call", params: {} }, - ) - - # The refresh token was never presented to the authorization server now being named. - assert_not_requested(:post, "#{@auth_base}/token") do |req| - URI.decode_www_form(req.body).to_h["grant_type"] == "refresh_token" - end - assert_equal([@auth_base], seen) - assert_equal(@auth_base, provider.tokens["issuer"]) - end - - private - - # Stubs PRM, AS metadata, /register, and /token so a full authorization - # flow runs. The /token stub echoes `requested_scope` so callers can - # assert the escalated scope was sent. - # `extra_as_metadata` lets a test advertise additional AS capabilities - # (e.g. `scopes_supported` for the offline_access interaction, or - # `client_id_metadata_document_supported` for the CIMD interaction) - # without duplicating the whole stub. - def stub_step_up_authorization_server(extra_as_metadata: {}) - stub_request(:get, @prm_url).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - resource: "https://srv.example.com/mcp", - authorization_servers: [@auth_base], - ), - ) - - stub_request(:get, "#{@auth_base}/.well-known/oauth-authorization-server").to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate({ - issuer: @auth_base, - authorization_endpoint: "#{@auth_base}/authorize", - token_endpoint: "#{@auth_base}/token", - registration_endpoint: "#{@auth_base}/register", - response_types_supported: ["code"], - grant_types_supported: ["authorization_code", "refresh_token"], - code_challenge_methods_supported: ["S256"], - token_endpoint_auth_methods_supported: ["none"], - }.merge(extra_as_metadata)), - ) - - stub_request(:post, "#{@auth_base}/register").to_return( - status: 201, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(client_id: "test-client"), - ) - - stub_request(:post, "#{@auth_base}/token").to_return do |request| - form = URI.decode_www_form(request.body).to_h - - { - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - access_token: "escalated-token", - token_type: "Bearer", - expires_in: 3600, - requested_scope: form["scope"], - grant_type_received: form["grant_type"], - ), - } - end - end - - def build_step_up_provider(grant_types: ["authorization_code"], client_id_metadata_document_url: nil) - state_holder = {} - captured_authorization_url = nil - provider = Provider.new( - client_metadata: { - client_name: "ruby-sdk-test", - redirect_uris: ["http://localhost:0/callback"], - grant_types: grant_types, - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(url) { - captured_authorization_url = url - state_holder[:state] = URI.decode_www_form(url.query).to_h.fetch("state") - }, - callback_handler: -> { ["test-auth-code", state_holder[:state]] }, - client_id_metadata_document_url: client_id_metadata_document_url, - ) - provider.save_tokens("access_token" => "initial-token", "token_type" => "Bearer") - - # `captured_authorization_url` is a closure variable that the redirect handler writes at flow time; - # expose its current value via a method on the provider so tests can assert on what was sent to /authorize. - provider.define_singleton_method(:last_authorization_url) { captured_authorization_url } - provider - end - - def build_provider(http_client_customizer: nil) - Provider.new( - client_metadata: { redirect_uris: ["http://localhost:0/callback"] }, - redirect_uri: "http://localhost:0/callback", - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - http_client_customizer: http_client_customizer, - ) - end - end - end - end -end diff --git a/test/mcp/client/oauth/id_jag_token_exchange_test.rb b/test/mcp/client/oauth/id_jag_token_exchange_test.rb deleted file mode 100644 index 23d152c..0000000 --- a/test/mcp/client/oauth/id_jag_token_exchange_test.rb +++ /dev/null @@ -1,118 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "webmock/minitest" -require "faraday" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class IDJAGTokenExchangeTest < Minitest::Test - def setup - WebMock.enable! - @token_endpoint = "https://idp.example.com/token" - end - - def teardown - WebMock.reset! - end - - def request_exchange - IDJAGTokenExchange.request( - token_endpoint: @token_endpoint, - id_token: "idp-id-token", - client_id: "idp-client", - audience: "https://auth.example.com", - resource: "https://srv.example.com/mcp", - ) - end - - def test_request_sends_rfc8693_token_exchange_parameters - stub_request(:post, @token_endpoint).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - access_token: "id-jag-assertion", - issued_token_type: "urn:ietf:params:oauth:token-type:id-jag", - token_type: "N_A", - ), - ) - - assertion = request_exchange - - assert_equal("id-jag-assertion", assertion) - assert_requested(:post, @token_endpoint) do |req| - form = URI.decode_www_form(req.body).to_h - form["grant_type"] == "urn:ietf:params:oauth:grant-type:token-exchange" && - form["subject_token"] == "idp-id-token" && - form["subject_token_type"] == "urn:ietf:params:oauth:token-type:id_token" && - form["requested_token_type"] == "urn:ietf:params:oauth:token-type:id-jag" && - form["audience"] == "https://auth.example.com" && - form["resource"] == "https://srv.example.com/mcp" && - form["client_id"] == "idp-client" - end - end - - def test_request_rejects_response_without_id_jag_token_type - # A plain access token is not an ID-JAG; presenting it as a - # jwt-bearer assertion would fail confusingly downstream. - stub_request(:post, @token_endpoint).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate( - access_token: "ordinary-token", - issued_token_type: "urn:ietf:params:oauth:token-type:access_token", - ), - ) - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/did not issue an ID-JAG/, error.message) - end - - def test_request_rejects_missing_access_token - stub_request(:post, @token_endpoint).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: JSON.generate(issued_token_type: "urn:ietf:params:oauth:token-type:id-jag"), - ) - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/missing `access_token`/, error.message) - end - - def test_request_raises_on_non_2xx_response - stub_request(:post, @token_endpoint).to_return(status: 400, body: JSON.generate(error: "invalid_grant")) - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/status 400/, error.message) - end - - def test_request_raises_on_unparseable_response - stub_request(:post, @token_endpoint).to_return(status: 200, body: "not json") - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/Failed to parse/, error.message) - end - - def test_request_raises_on_non_object_json_response - stub_request(:post, @token_endpoint).to_return(status: 200, body: "[]") - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/not a JSON object/, error.message) - end - - def test_request_refuses_a_response_body_over_the_cap - stub_request(:post, @token_endpoint).to_return( - status: 200, - headers: { "Content-Type" => "application/json" }, - body: "a" * (4 * 1024 * 1024 + 1), - ) - - error = assert_raises(IDJAGTokenExchange::ExchangeError) { request_exchange } - assert_match(/exceeds \d+ bytes/, error.message) - end - end - end - end -end diff --git a/test/mcp/client/oauth/jwt_client_assertion_test.rb b/test/mcp/client/oauth/jwt_client_assertion_test.rb deleted file mode 100644 index 412f966..0000000 --- a/test/mcp/client/oauth/jwt_client_assertion_test.rb +++ /dev/null @@ -1,166 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class JWTClientAssertionTest < Minitest::Test - ES256_COMPONENT_BYTES = 32 - - # `OpenSSL::PKey::EC.generate` only exists from the openssl gem 2.2 (Ruby 3.0), - # while `EC#generate_key` raises on openssl 3.0+ where PKey objects are immutable, - # so branch on availability to keep CI green on every supported Ruby. - def generate_ec_key(curve) - if OpenSSL::PKey::EC.respond_to?(:generate) - OpenSSL::PKey::EC.generate(curve) - else - OpenSSL::PKey::EC.new(curve).tap(&:generate_key) - end - end - - def es256_key - @es256_key ||= generate_ec_key("prime256v1") - end - - def rs256_key - @rs256_key ||= OpenSSL::PKey::RSA.new(2048) - end - - def generate(private_key: es256_key, signing_algorithm: "ES256", **kwargs) - JWTClientAssertion.generate( - client_id: "cc-client", - audience: "https://auth.example.com", - private_key: private_key, - signing_algorithm: signing_algorithm, - **kwargs, - ) - end - - def decode_segment(segment) - JSON.parse(Base64.urlsafe_decode64(segment + "=" * (-segment.length % 4))) - end - - # JWS ES256 signatures are the raw 64-byte `r || s` concatenation; - # OpenSSL verifies the ASN.1 DER form, so convert back for verification. - def ecdsa_raw_to_der(raw) - r = OpenSSL::BN.new(raw[0, ES256_COMPONENT_BYTES], 2) - s = OpenSSL::BN.new(raw[ES256_COMPONENT_BYTES, ES256_COMPONENT_BYTES], 2) - OpenSSL::ASN1::Sequence.new([OpenSSL::ASN1::Integer.new(r), OpenSSL::ASN1::Integer.new(s)]).to_der - end - - def test_generate_builds_compact_jws_with_rfc7523_claims - before = Time.now.to_i - assertion = generate - after = Time.now.to_i - - header_segment, payload_segment, _signature_segment = assertion.split(".") - header = decode_segment(header_segment) - claims = decode_segment(payload_segment) - - assert_equal({ "alg" => "ES256", "typ" => "JWT" }, header) - assert_equal("cc-client", claims["iss"]) - assert_equal("cc-client", claims["sub"]) - assert_equal("https://auth.example.com", claims["aud"]) - assert_includes(before..after, claims["iat"]) - assert_equal(claims["iat"] + JWTClientAssertion::DEFAULT_LIFETIME, claims["exp"]) - refute_empty(claims["jti"]) - end - - def test_generate_uses_unpadded_base64url_segments - assertion = generate - - segments = assertion.split(".") - assert_equal(3, segments.size) - segments.each do |segment| - refute_match(%r{[+/=]}, segment, "JWS segments must be unpadded base64url") - end - end - - def test_generate_es256_signature_verifies_with_the_public_key - assertion = generate - - header_segment, payload_segment, signature_segment = assertion.split(".") - raw_signature = Base64.urlsafe_decode64(signature_segment + "=" * (-signature_segment.length % 4)) - - assert_equal(ES256_COMPONENT_BYTES * 2, raw_signature.bytesize) - assert( - es256_key.verify( - OpenSSL::Digest.new("SHA256"), - ecdsa_raw_to_der(raw_signature), - "#{header_segment}.#{payload_segment}", - ), - "ES256 signature must verify against the signing input", - ) - end - - def test_generate_rs256_signature_verifies_with_the_public_key - assertion = generate(private_key: rs256_key, signing_algorithm: "RS256") - - header_segment, payload_segment, signature_segment = assertion.split(".") - signature = Base64.urlsafe_decode64(signature_segment + "=" * (-signature_segment.length % 4)) - - assert_equal("RS256", decode_segment(header_segment)["alg"]) - assert(rs256_key.verify(OpenSSL::Digest.new("SHA256"), signature, "#{header_segment}.#{payload_segment}")) - end - - def test_generate_accepts_pem_encoded_private_key - assertion = generate(private_key: es256_key.to_pem) - - refute_empty(assertion) - end - - def test_generate_honors_lifetime_override - assertion = generate(lifetime: 60) - - claims = decode_segment(assertion.split(".")[1]) - assert_equal(claims["iat"] + 60, claims["exp"]) - end - - def test_generate_uses_a_unique_jti_per_assertion - jtis = Array.new(2) { decode_segment(generate.split(".")[1])["jti"] } - - refute_equal(jtis[0], jtis[1]) - end - - def test_generate_rejects_unsupported_algorithm - assert_raises(JWTClientAssertion::UnsupportedAlgorithmError) do - generate(signing_algorithm: "HS256") - end - end - - def test_generate_rejects_key_algorithm_mismatch - assert_raises(JWTClientAssertion::InvalidKeyError) do - generate(private_key: rs256_key, signing_algorithm: "ES256") - end - - assert_raises(JWTClientAssertion::InvalidKeyError) do - generate(private_key: es256_key, signing_algorithm: "RS256") - end - end - - def test_generate_rejects_ec_key_on_the_wrong_curve - assert_raises(JWTClientAssertion::InvalidKeyError) do - generate(private_key: generate_ec_key("secp384r1"), signing_algorithm: "ES256") - end - end - - def test_generate_rejects_unparseable_pem - assert_raises(JWTClientAssertion::InvalidKeyError) do - generate(private_key: "not a pem") - end - end - - def test_generate_rejects_public_only_key - # `RSA#public_key` is available on every supported openssl version, - # unlike `public_to_pem` (openssl 3.0+), so the public-only check is - # exercised with an RSA key. - assert_raises(JWTClientAssertion::InvalidKeyError) do - generate(private_key: rs256_key.public_key, signing_algorithm: "RS256") - end - end - end - end - end -end diff --git a/test/mcp/client/oauth/pkce_test.rb b/test/mcp/client/oauth/pkce_test.rb deleted file mode 100644 index 49a628b..0000000 --- a/test/mcp/client/oauth/pkce_test.rb +++ /dev/null @@ -1,34 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "base64" -require "digest" -require "mcp/client/oauth/pkce" - -module MCP - class Client - module OAuth - class PKCETest < Minitest::Test - def test_generate_returns_verifier_and_s256_challenge - result = PKCE.generate - - assert_kind_of(String, result[:code_verifier]) - assert_operator(result[:code_verifier].length, :>=, 43) - assert_operator(result[:code_verifier].length, :<=, 128) - assert_equal("S256", result[:code_challenge_method]) - - expected = Base64.urlsafe_encode64(Digest::SHA256.digest(result[:code_verifier]), padding: false) - assert_equal(expected, result[:code_challenge]) - end - - def test_generate_produces_distinct_values - a = PKCE.generate - b = PKCE.generate - - refute_equal(a[:code_verifier], b[:code_verifier]) - refute_equal(a[:code_challenge], b[:code_challenge]) - end - end - end - end -end diff --git a/test/mcp/client/oauth/provider_test.rb b/test/mcp/client/oauth/provider_test.rb deleted file mode 100644 index 7425131..0000000 --- a/test/mcp/client/oauth/provider_test.rb +++ /dev/null @@ -1,237 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "mcp/client/oauth" - -module MCP - class Client - module OAuth - class ProviderTest < Minitest::Test - # Builds a complete Provider argument hash whose `client_metadata` - # registers the same `redirect_uri` that is being asserted on. - # The registered-URI check in `Provider#initialize` requires the two to - # match, so accept-path tests need them paired. - def args_for(redirect_uri) - { - client_metadata: { - redirect_uris: [redirect_uri], - grant_types: ["authorization_code"], - response_types: ["code"], - token_endpoint_auth_method: "none", - }, - redirect_uri: redirect_uri, - redirect_handler: ->(_url) {}, - callback_handler: -> { ["code", "state"] }, - } - end - - def test_initialize_accepts_https_redirect_uri - provider = Provider.new(**args_for("https://app.example.com/callback")) - - assert_equal("https://app.example.com/callback", provider.redirect_uri) - end - - def test_initialize_accepts_loopback_http_redirect_uri - ["http://localhost/callback", "http://127.0.0.1:3000/cb", "http://[::1]/cb"].each do |uri| - provider = Provider.new(**args_for(uri)) - assert_equal(uri, provider.redirect_uri) - end - end - - def test_initialize_defaults_http_client_customizer_to_nil - assert_nil(Provider.new(**args_for("https://app.example.com/callback")).http_client_customizer) - end - - def test_initialize_keeps_the_http_client_customizer - customizer = ->(_faraday) {} - provider = Provider.new(**args_for("https://app.example.com/callback"), http_client_customizer: customizer) - - assert_same(customizer, provider.http_client_customizer) - end - - def test_initialize_rejects_a_non_callable_http_client_customizer - # A connection object in place of a callable is the likely mistake. - error = assert_raises(ArgumentError) do - Provider.new(**args_for("https://app.example.com/callback"), http_client_customizer: Object.new) - end - - assert_equal("http_client_customizer must respond to call (got Object).", error.message) - end - - def test_initialize_rejects_non_loopback_http_redirect_uri - # Communication Security: a non-loopback `http://` redirect URI would - # let an attacker steal the authorization code from a network sniffer, - # so the provider must refuse to construct. - assert_raises(Provider::InsecureRedirectURIError) do - Provider.new(**args_for("http://app.example.com/callback")) - end - end - - def test_initialize_rejects_non_http_scheme_redirect_uri - assert_raises(Provider::InsecureRedirectURIError) do - Provider.new(**args_for("ftp://app.example.com/callback")) - end - end - - def test_initialize_rejects_hostname_tricks_that_resemble_loopback - ["http://127.attacker.com/cb", "http://127.0.0.1.evil.com/cb", "http://foo.localhost/cb"].each do |uri| - assert_raises(Provider::InsecureRedirectURIError, "should reject #{uri}") do - Provider.new(**args_for(uri)) - end - end - end - - def test_initialize_rejects_redirect_uri_not_listed_in_client_metadata - # Per the OAuth Dynamic Client Registration response, the AS will - # bind the client_id to a specific set of redirect_uris and reject any - # authorization request that uses something else. Detect that mismatch - # at Provider construction so the failure surfaces immediately. - args = args_for("http://localhost:0/callback") - args[:redirect_uri] = "http://localhost:0/different" - - assert_raises(Provider::UnregisteredRedirectURIError) do - Provider.new(**args) - end - end - - def test_initialize_accepts_redirect_uri_with_string_keys_in_client_metadata - # `client_metadata` is hand-built by callers, so accept either symbol - # or string keys for `redirect_uris`. - args = args_for("http://localhost:0/callback") - args[:client_metadata] = { "redirect_uris" => ["http://localhost:0/callback"] } - - provider = Provider.new(**args) - assert_equal("http://localhost:0/callback", provider.redirect_uri) - end - - def test_initialize_defaults_client_id_metadata_document_url_to_nil - provider = Provider.new(**args_for("http://localhost:0/callback")) - - assert_nil(provider.client_id_metadata_document_url) - end - - def test_initialize_accepts_https_client_id_metadata_document_url - args = args_for("http://localhost:0/callback").merge( - client_id_metadata_document_url: "https://app.example.com/client-metadata.json", - ) - - provider = Provider.new(**args) - assert_equal( - "https://app.example.com/client-metadata.json", - provider.client_id_metadata_document_url, - ) - end - - def test_initialize_rejects_http_client_id_metadata_document_url - # The loopback `http` carve-out used for discovery does not extend to the CIMD URL: - # the URL is sent to the AS as the OAuth `client_id` and travels off-loopback, - # so MCP requires `https`. - ["http://localhost:8080/client-metadata.json", "http://app.example.com/cm"].each do |uri| - args = args_for("http://localhost:0/callback").merge(client_id_metadata_document_url: uri) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError, "should reject #{uri}") do - Provider.new(**args) - end - end - end - - def test_initialize_rejects_non_https_scheme_client_id_metadata_document_url - ["ftp://app.example.com/cm", "file:///cm", "foo://bar/cm"].each do |uri| - args = args_for("http://localhost:0/callback").merge(client_id_metadata_document_url: uri) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError, "should reject #{uri}") do - Provider.new(**args) - end - end - end - - def test_initialize_rejects_client_id_metadata_document_url_without_path - # The CIMD document is a discrete resource, not the origin. - # A bare origin or root-path URL would let two different deployments at - # the same origin shadow each other under one `client_id`. - ["https://app.example.com", "https://app.example.com/"].each do |uri| - args = args_for("http://localhost:0/callback").merge(client_id_metadata_document_url: uri) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError, "should reject #{uri}") do - Provider.new(**args) - end - end - end - - def test_initialize_rejects_client_id_metadata_document_url_with_fragment - # A fragment is never sent to the server; embedding one in the `client_id` value - # would make the OAuth `client_id` and the URL the AS dereferences point at different artifacts. - args = args_for("http://localhost:0/callback").merge( - client_id_metadata_document_url: "https://app.example.com/cm#frag", - ) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError) do - Provider.new(**args) - end - end - - def test_initialize_rejects_client_id_metadata_document_url_with_query - args = args_for("http://localhost:0/callback").merge( - client_id_metadata_document_url: "https://app.example.com/cm?x=1", - ) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError) do - Provider.new(**args) - end - end - - def test_initialize_rejects_client_id_metadata_document_url_with_userinfo - # Embedding credentials in the `client_id` leaks them to every AS - # log line and to the conformance audit trail. - args = args_for("http://localhost:0/callback").merge( - client_id_metadata_document_url: "https://user:pass@app.example.com/cm", - ) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError) do - Provider.new(**args) - end - end - - def test_initialize_rejects_client_id_metadata_document_url_with_dot_segments - # `https://x/a/./b` and `https://x/a/b` are RFC 3986 equivalent, - # so accepting both would let one client publish under two `client_id` values. - # Reject `.`/`..` (including percent-encoded `.`). - [ - "https://app.example.com/./cm", - "https://app.example.com/a/../cm", - "https://app.example.com/%2E/cm", - ].each do |uri| - args = args_for("http://localhost:0/callback").merge(client_id_metadata_document_url: uri) - assert_raises(Provider::InvalidClientIDMetadataDocumentURLError, "should reject #{uri}") do - Provider.new(**args) - end - end - end - - def test_authorization_flow_is_authorization_code - provider = Provider.new(**args_for("https://app.example.com/callback")) - - assert_equal(:authorization_code, provider.authorization_flow) - end - - def test_token_request_params_is_nil_by_default - provider = Provider.new(**args_for("https://app.example.com/callback")) - - assert_nil(provider.token_request_params) - end - - def test_initialize_keeps_a_frozen_copy_of_token_request_params - params = { "audience" => +"https://api.example.com" } - provider = Provider.new(**args_for("https://app.example.com/callback"), token_request_params: params) - - params["audience"] << "/changed" - - assert_equal({ "audience" => "https://api.example.com" }, provider.token_request_params) - assert_predicate(provider.token_request_params, :frozen?) - end - - def test_initialize_rejects_token_request_params_that_the_sdk_sets_itself - error = assert_raises(Flow::InvalidTokenRequestParamsError) do - Provider.new(**args_for("https://app.example.com/callback"), token_request_params: { "code" => "x" }) - end - - assert_includes(error.message, '"code"') - end - end - end - end -end diff --git a/test/mcp/client/stdio_test.rb b/test/mcp/client/stdio_test.rb deleted file mode 100644 index 08e8d17..0000000 --- a/test/mcp/client/stdio_test.rb +++ /dev/null @@ -1,1957 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" -require "json" -require "mcp/client" -require "mcp/client/stdio" -require "mcp/client/tool" - -module MCP - class Client - class StdioTest < Minitest::Test - include DeprecationWarningTestHelper - - def test_send_request_raises_when_connect_not_called - Open3.expects(:popen3).never - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - error = assert_raises(RuntimeError) do - transport.send_request(request: { jsonrpc: "2.0", id: "test-id", method: "tools/list" }) - end - - assert_equal("MCP::Client#connect must be called before sending requests.", error.message) - end - - def test_send_request_starts_process_and_returns_response - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - # Simulate server responses: initialize response, then tools/list response - server_thread = Thread.new do - # Read and respond to initialize request - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - init_response = { - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - } - stdout_write.puts(JSON.generate(init_response)) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read and respond to tools/list request - tools_line = stdin_read.gets - tools_request = JSON.parse(tools_line) - tools_response = { - jsonrpc: "2.0", - id: tools_request["id"], - result: { tools: [{ name: "test_tool", description: "A test tool", inputSchema: {} }] }, - } - stdout_write.puts(JSON.generate(tools_response)) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - - assert_equal("test-id", response["id"]) - assert_equal(1, response.dig("result", "tools").size) - assert_equal("test_tool", response.dig("result", "tools", 0, "name")) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - stderr_read.close - end - - def test_send_request_answers_a_server_ping_inline - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - pong_line = nil - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification, then the tools/list request. - stdin_read.gets - stdin_read.gets - - # Ping the client while it awaits the response; the receiver "MUST respond promptly". - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "srv-ping-1", method: "ping" })) - stdout_write.flush - - pong_line = stdin_read.gets - - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "test-id", result: { tools: [] } })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - server_thread.join - - assert_equal("test-id", response["id"]) - pong = JSON.parse(pong_line) - assert_equal("srv-ping-1", pong["id"]) - assert_equal({}, pong["result"]) - refute(pong.key?("error")) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_a_server_ping_reusing_the_awaited_id_is_answered_and_not_returned_as_the_response - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - pong_line = nil - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification, then the tools/list request. - stdin_read.gets - stdin_read.gets - - # JSON-RPC id spaces are per sender, so a server ping may reuse the id the client - # is awaiting; it must still be answered rather than treated as the response. - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "test-id", method: "ping" })) - stdout_write.flush - - pong_line = stdin_read.gets - - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "test-id", result: { tools: [] } })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - server_thread.join - - assert_equal("test-id", response["id"]) - assert_empty(response.dig("result", "tools")) - pong = JSON.parse(pong_line) - assert_equal("test-id", pong["id"]) - assert_equal({}, pong["result"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_a_pong_that_cannot_be_written_does_not_fail_the_awaited_request - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification, then the tools/list request. - stdin_read.gets - stdin_read.gets - - # Break the write path: the pong cannot be delivered, and that must not fail the request. - stdin_read.close - - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "srv-ping-1", method: "ping" })) - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "test-id", result: { tools: [] } })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - - assert_equal("test-id", response["id"]) - assert_empty(response.dig("result", "tools")) - ensure - server_thread.join - stdin_read.close unless stdin_read.closed? - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_a_ping_with_a_malformed_id_is_not_answered - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - pong_line = nil - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification, then the tools/list request. - stdin_read.gets - stdin_read.gets - - # A Hash id is not a JSON-RPC id; the reference SDKs reject such frames outright. - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: { "x" => 1 }, method: "ping" })) - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "srv-ping-2", method: "ping" })) - stdout_write.flush - - # The single pong that arrives must answer the well-formed ping, not the malformed one. - pong_line = stdin_read.gets - - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: "test-id", result: { tools: [] } })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - server_thread.join - - assert_equal("test-id", response["id"]) - pong = JSON.parse(pong_line) - assert_equal("srv-ping-2", pong["id"]) - assert_equal({}, pong["result"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_skips_notifications - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - # Handle initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read tools/list request - stdin_read.gets - - # Send a notification before the response - notification = { jsonrpc: "2.0", method: "notifications/tools/list_changed" } - stdout_write.puts(JSON.generate(notification)) - stdout_write.flush - - # Then send the actual response - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: "test-id", - result: { tools: [] }, - })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - - assert_equal("test-id", response["id"]) - assert_empty(response.dig("result", "tools")) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_skips_non_object_frames - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read tools/list request - stdin_read.gets - - # Non-object frames are skipped like any other non-matching frame. - stdout_write.puts("[[]]") - stdout_write.puts("null") - stdout_write.flush - - # Then send the actual response - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: "test-id", - result: { tools: [] }, - })) - stdout_write.flush - end - - transport.connect - response = transport.send_request(request: request) - - assert_equal("test-id", response["id"]) - assert_empty(response.dig("result", "tools")) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_raises_error_when_process_exits - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - - dead_thread = mock("wait_thread") - dead_thread.stubs(:alive?).returns(false) - dead_thread.stubs(:value).returns(nil) - - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, dead_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - - error = assert_raises(RequestHandlerError) do - transport.connect - end - - assert_equal("Server process has exited", error.message) - assert_equal(:internal_error, error.error_type) - ensure - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_raises_error_on_closed_stdout - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - # Handle initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read tools/list request, then close stdout - stdin_read.gets - stdout_write.close - end - - transport.connect - error = assert_raises(RequestHandlerError) do - transport.send_request(request: request) - end - - assert_equal("Server process closed stdout unexpectedly", error.message) - assert_equal(:internal_error, error.error_type) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_close_resets_state - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, stderr_write = IO.pipe - - wait_thread = mock("wait_thread") - wait_thread.stubs(:alive?).returns(true) - wait_thread.stubs(:value).returns(nil) - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - - assert(transport.instance_variable_get(:@started)) - - transport.close - - refute(transport.instance_variable_get(:@started)) - refute(transport.instance_variable_get(:@initialized)) - ensure - stdin_read.close - begin - stdin_write.close - rescue - nil - end - begin - stdout_read.close - rescue - nil - end - stdout_write.close - begin - stderr_read.close - rescue - nil - end - stderr_write.close - end - - def test_multiple_send_requests_do_not_reinitialize - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - received_methods = [] - - server_thread = Thread.new do - # First call: initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - received_methods << init_request["method"] - - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - notification_line = stdin_read.gets - received_methods << JSON.parse(notification_line)["method"] - - # First request: tools/list - first_line = stdin_read.gets - first_request = JSON.parse(first_line) - received_methods << first_request["method"] - - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: first_request["id"], - result: { tools: [] }, - })) - stdout_write.flush - - # Second request: tools/list (no re-initialization) - second_line = stdin_read.gets - second_request = JSON.parse(second_line) - received_methods << second_request["method"] - - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: second_request["id"], - result: { tools: [] }, - })) - stdout_write.flush - end - - transport.connect - transport.send_request(request: { jsonrpc: "2.0", id: "first", method: "tools/list" }) - transport.send_request(request: { jsonrpc: "2.0", id: "second", method: "tools/list" }) - - assert_equal( - ["initialize", "notifications/initialized", "tools/list", "tools/list"], - received_methods, - ) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_env_is_passed_to_process - transport = Stdio.new(command: "ruby", args: ["server.rb"], env: { "FOO" => "bar" }) - - Open3.expects(:popen3).with({ "FOO" => "bar" }, "ruby", "server.rb").returns( - [StringIO.new, StringIO.new, StringIO.new, mock_wait_thread], - ) - - transport.start - end - - def test_send_request_raises_error_on_invalid_json - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - # Handle initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read tools/list request, then send invalid JSON - stdin_read.gets - stdout_write.puts("not valid json") - stdout_write.flush - end - - transport.connect - error = assert_raises(RequestHandlerError) do - transport.send_request(request: request) - end - - assert_equal("Failed to parse server response", error.message) - assert_equal(:internal_error, error.error_type) - assert_instance_of(JSON::ParserError, error.original_error) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_close_kills_process_on_timeout - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - hanging_thread = mock("wait_thread") - hanging_thread.stubs(:alive?).returns(true) - hanging_thread.stubs(:pid).returns(99999) - hanging_thread.stubs(:value).raises(Timeout::Error) - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, hanging_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - - Process.expects(:kill).with("TERM", 99999).once - Process.expects(:kill).with("KILL", 99999).once - - transport.close - ensure - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_read_response_raises_error_on_timeout - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"], read_timeout: 0.01) - - request = { - jsonrpc: "2.0", - id: "test-id", - method: "tools/list", - } - - server_thread = Thread.new do - # Handle initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read tools/list request but don't respond (simulate timeout) - stdin_read.gets - end - - transport.connect - error = assert_raises(RequestHandlerError) do - transport.send_request(request: request) - end - - assert_equal("Timed out waiting for server response", error.message) - assert_equal(:internal_error, error.error_type) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_raises_error_when_stdin_is_closed - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - # Handle initialize handshake - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification - stdin_read.gets - - # Read and respond to first request - line = stdin_read.gets - request = JSON.parse(line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: request["id"], - result: {}, - })) - stdout_write.flush - end - - transport.connect - # Complete a successful request before breaking the pipe. - transport.send_request(request: { jsonrpc: "2.0", id: "setup", method: "ping" }) - server_thread.join - - # Now close stdin to simulate broken pipe - stdin_write.close - - error = assert_raises(RequestHandlerError) do - transport.send_request(request: { jsonrpc: "2.0", id: "test-id", method: "tools/list" }) - end - - assert_equal("Failed to write to server process", error.message) - assert_equal(:internal_error, error.error_type) - ensure - stdin_read.close - begin - stdin_write.close - rescue - nil - end - stdout_read.close - stdout_write.close - end - - def test_close_is_noop_when_not_started - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - # Should not raise - transport.close - end - - def test_start_raises_error_when_already_started - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - - error = assert_raises(RuntimeError) do - transport.start - end - - assert_equal("MCP::Client::Stdio already started", error.message) - ensure - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_start_raises_error_for_invalid_command - Open3.stubs(:popen3).raises(Errno::ENOENT.new("No such file or directory - nonexistent_command")) - - transport = Stdio.new(command: "nonexistent_command") - - error = assert_raises(RequestHandlerError) do - transport.start - end - - assert_match(/Failed to spawn server process/, error.message) - assert_equal(:internal_error, error.error_type) - assert_instance_of(Errno::ENOENT, error.original_error) - end - - def test_connect_performs_initialize_handshake_explicitly - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - received_methods = [] - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - received_methods << init_request["method"] - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: { tools: {} }, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - )) - stdout_write.flush - - notification_line = stdin_read.gets - received_methods << JSON.parse(notification_line)["method"] - end - - result = transport.connect - - server_thread.join - - assert_equal(["initialize", "notifications/initialized"], received_methods) - assert_equal("2025-11-25", result["protocolVersion"]) - assert_equal({ "tools" => {} }, result["capabilities"]) - assert_equal({ "name" => "test-server", "version" => "1.0.0" }, result["serverInfo"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_does_not_warn_after_explicit_connect - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - )) - stdout_write.flush - - stdin_read.gets - - ping_line = stdin_read.gets - ping_request = JSON.parse(ping_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: ping_request["id"], - result: {}, - )) - stdout_write.flush - end - - assert_silent do - transport.connect - end - - response = nil - assert_silent do - response = transport.send_request(request: { jsonrpc: "2.0", id: "ping-id", method: "ping" }) - end - - assert_equal("ping-id", response["id"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_caches_server_info - transport, server_thread, pipes = stub_successful_connect - - transport.connect - - assert_equal("2025-11-25", transport.server_info["protocolVersion"]) - assert_equal({ "tools" => {} }, transport.server_info["capabilities"]) - ensure - server_thread.join - pipes.each(&:close) - end - - def test_connect_is_idempotent - transport, server_thread, pipes = stub_successful_connect - - first_result = transport.connect - second_result = transport.connect - - assert_same(first_result, second_result) - ensure - server_thread.join - pipes.each(&:close) - end - - def test_connect_accepts_custom_parameters - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - sent_init_params = nil - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - sent_init_params = init_request["params"] - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2025-03-26" }, - )) - stdout_write.flush - stdin_read.gets - end - - transport.connect( - client_info: { name: "my-app", version: "9.9" }, - protocol_version: "2025-03-26", - capabilities: { roots: { listChanged: true } }, - ) - - assert_equal("2025-03-26", sent_init_params["protocolVersion"]) - assert_equal({ "name" => "my-app", "version" => "9.9" }, sent_init_params["clientInfo"]) - assert_equal({ "roots" => { "listChanged" => true } }, sent_init_params["capabilities"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_adopts_a_counter_offered_protocol_version - # A server may answer `initialize` with a version other than the one offered, and the connection - # then speaks the answer rather than the offer. This server counter-offers a handshake version - # to clients asking `initialize` for a modern one, which only resolves anything because - # clients behave this way. - counter_offered = "2025-06-18" - refute_equal( - counter_offered, - MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, - "the counter-offer has to differ from the offer for this to test anything", - ) - - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - offered = nil - - server_thread = Thread.new do - init_request = JSON.parse(stdin_read.gets) - offered = init_request.dig("params", "protocolVersion") - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: counter_offered }, - )) - stdout_write.flush - stdin_read.gets - end - - transport.connect - - assert_equal(MCP::Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, offered) - assert_equal(counter_offered, transport.protocol_version) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_rejects_a_modern_protocol_version_in_the_initialize_result - # A server answering `initialize` with a modern version is refused like an unknown one: - # the handshake settles on a legacy version by definition (SEP-2575 era model), - # and the TypeScript and Python clients refuse a modern counter-offer the same way. - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2026-07-28" }, - )) - stdout_write.flush - end - - error = assert_raises(RequestHandlerError) do - transport.connect(capabilities: { roots: { listChanged: true }, sampling: {} }) - end - - assert_includes(error.message, "2026-07-28") - refute_predicate(transport, :connected?) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_raises_argument_error_for_an_explicit_modern_protocol_version_on_the_legacy_handshake - # Validated before the child process is spawned: a pure argument error must not leave - # an orphaned server process behind. - Open3.expects(:popen3).never - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - error = assert_raises(ArgumentError) do - transport.connect(protocol_version: "2026-07-28", mode: :legacy) - end - - assert_includes(error.message, "cannot be negotiated through the legacy `initialize` handshake") - end - - def test_connect_raises_on_jsonrpc_error_response - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - error: { code: -32602, message: "boom" }, - )) - stdout_write.flush - end - - error = assert_raises(RequestHandlerError) do - transport.connect - end - - assert_includes(error.message, "boom") - refute_predicate(transport, :connected?) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_raises_on_missing_result - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - )) - stdout_write.flush - end - - error = assert_raises(RequestHandlerError) do - transport.connect - end - - assert_includes(error.message, "missing result in response") - refute_predicate(transport, :connected?) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_raises_on_non_hash_result - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: [], - )) - stdout_write.flush - end - - error = assert_raises(RequestHandlerError) do - transport.connect - end - - assert_includes(error.message, "missing result in response") - refute_predicate(transport, :connected?) - assert_nil(transport.server_info) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_clears_state_when_initialized_notification_fails - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - # Close stdin_read first so the next write to @stdin (the notification) raises EPIPE. - stdin_read.close - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2025-11-25" }, - )) - stdout_write.flush - end - - assert_raises(RequestHandlerError) do - transport.connect - end - - refute_predicate(transport, :connected?) - assert_nil(transport.server_info) - ensure - server_thread.join - [stdin_read, stdin_write, stdout_read, stdout_write].each do |io| - io.close unless io.closed? - end - end - - def test_connect_can_be_retried_after_failed_handshake - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - # First handshake: server returns an unsupported protocol version. - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "1999-01-01" }, - )) - stdout_write.flush - - # Second handshake: server returns a supported protocol version. - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2025-11-25" }, - )) - stdout_write.flush - stdin_read.gets - end - - assert_raises(RequestHandlerError) do - transport.connect - end - - refute_predicate(transport, :connected?) - assert_nil(transport.server_info) - - result = transport.connect - - server_thread.join - - assert_predicate(transport, :connected?) - assert_equal("2025-11-25", result["protocolVersion"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connect_raises_on_unsupported_protocol_version - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - sent_methods = [] - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - sent_methods << init_request["method"] - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "1999-01-01" }, - )) - stdout_write.flush - end - - error = assert_raises(RequestHandlerError) do - transport.connect - end - - assert_includes(error.message, "unsupported protocol version") - assert_includes(error.message, "1999-01-01") - assert_equal(["initialize"], sent_methods) - refute_predicate(transport, :connected?) - assert_nil(transport.server_info) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_connected_is_false_before_first_send_request - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - refute_predicate(transport, :connected?) - end - - def test_connected_is_true_after_explicit_connect - transport, server_thread, pipes = stub_successful_connect - - refute_predicate(transport, :connected?) - - transport.connect - - assert_predicate(transport, :connected?) - ensure - server_thread.join - pipes.each(&:close) - end - - def test_connected_is_false_after_close - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, stderr_write = IO.pipe - - wait_thread = mock("wait_thread") - wait_thread.stubs(:alive?).returns(true) - wait_thread.stubs(:value).returns(nil) - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - transport.instance_variable_set(:@initialized, true) - - assert_predicate(transport, :connected?) - - transport.close - - refute_predicate(transport, :connected?) - ensure - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read, stderr_write].each do |io| - io.close unless io.closed? - end - end - - def test_server_info_is_nil_before_connect - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - assert_nil(transport.server_info) - end - - def test_server_info_is_cleared_after_close - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, stderr_write = IO.pipe - - wait_thread = mock("wait_thread") - wait_thread.stubs(:alive?).returns(true) - wait_thread.stubs(:value).returns(nil) - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.start - transport.instance_variable_set(:@initialized, true) - transport.instance_variable_set(:@server_info, { "protocolVersion" => "2025-11-25" }) - - transport.close - - assert_nil(transport.server_info) - ensure - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read, stderr_write].each do |io| - io.close unless io.closed? - end - end - - def test_new_raises_argument_error_when_max_line_bytes_is_not_a_positive_integer - [nil, 0, -1, 1.5, "1024"].each do |invalid| - error = assert_raises(ArgumentError) do - Stdio.new(command: "ruby", args: ["server.rb"], max_line_bytes: invalid) - end - assert_equal("max_line_bytes must be a positive Integer", error.message) - end - end - - def test_send_request_raises_when_response_frame_exceeds_max_line_bytes - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"], max_line_bytes: 1024) - - request = { jsonrpc: "2.0", id: "test-id", method: "tools/list" } - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - # Read initialized notification. - stdin_read.gets - - # Read tools/list request, then stream an unbounded frame with no newline. - stdin_read.gets - stdout_write.write("A" * 2000) - stdout_write.flush - end - - transport.connect - - error = assert_raises(RequestHandlerError) do - transport.send_request(request: request) - end - - assert_match(/exceeds 1024 bytes without a newline/, error.message) - assert_equal(:internal_error, error.error_type) - # The stream is desynced (leftover bytes in the pipe), so the transport is closed - # rather than left resumable on a corrupt stream. - refute_predicate(transport, :connected?) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_request_accepts_response_within_custom_max_line_bytes - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"], max_line_bytes: 1024) - - request = { jsonrpc: "2.0", id: "test-id", method: "tools/list" } - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - })) - stdout_write.flush - - stdin_read.gets - - tools_line = stdin_read.gets - tools_request = JSON.parse(tools_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: tools_request["id"], - result: { tools: [] }, - })) - stdout_write.flush - end - - transport.connect - - response = transport.send_request(request: request) - - assert_equal("test-id", response["id"]) - assert_equal({ "tools" => [] }, response["result"]) - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_send_notification_writes_json_line_without_waiting_for_response - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - notification = { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "abc-123", reason: "user cancel" }, - } - - # Server: respond to initialize, then read the notification line. - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2025-11-25", capabilities: {}, serverInfo: { name: "test", version: "1.0.0" } }, - })) - stdout_write.flush - - stdin_read.gets # skip initialized notification - - stdin_read.gets # read the cancellation notification line we are testing - end - - result = transport.send_notification(notification: notification) - - assert_nil(result, "send_notification must return nil (no response expected)") - ensure - server_thread.join - stdin_read.close - stdin_write.close - stdout_read.close - stdout_write.close - end - - def test_concurrent_write_message_does_not_interleave_lines - # Regression: cancellation can call `send_notification` from a thread while `send_request` is mid-flight - # on another thread. The two writes must serialize so JSON-RPC lines do not interleave on stdin. - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - # Server: respond to initialize, then accept multiple lines. - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { protocolVersion: "2025-11-25", capabilities: {}, serverInfo: { name: "t", version: "1.0.0" } }, - })) - stdout_write.flush - stdin_read.gets # initialized - end - - # Force initialization synchronously. - notification = { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "warmup" }, - } - transport.send_notification(notification: notification) - server_thread.join - - # Now hammer send_notification from many threads concurrently. Each line is one JSON object terminated by `\n`; - # if writes interleave, the received text would not be one valid JSON object per line. - threads = 8.times.map do |i| - Thread.new do - 10.times do |j| - transport.send_notification( - notification: { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "t#{i}-#{j}" }, - }, - ) - end - end - end - threads.each(&:join) - - # Drain everything written to stdin and verify each line parses as JSON. - stdin_write.close - lines = [] - until stdin_read.eof? - line = stdin_read.gets - break if line.nil? - - lines << line - end - lines.each do |line| - assert(JSON.parse(line.strip), "interleaved write produced unparseable line: #{line.inspect}") - end - assert_operator(lines.size, :>=, 80, "expected at least 80 notification lines") - ensure - stdout_read.close - stdout_write.close - begin - stderr_read.close - rescue - nil - end - end - - private - - def stub_successful_connect - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - init_line = stdin_read.gets - init_request = JSON.parse(init_line) - stdout_write.puts(JSON.generate( - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: { tools: {} }, - serverInfo: { name: "test-server", version: "1.0.0" }, - }, - )) - stdout_write.flush - stdin_read.gets - end - - [transport, server_thread, [stdin_read, stdin_write, stdout_read, stdout_write]] - end - - def test_send_request_allows_server_discover_before_connect - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - discover_request = JSON.parse(stdin_read.gets) - response = { - jsonrpc: "2.0", - id: discover_request["id"], - result: { supportedVersions: ["2026-07-28"], ttlMs: 0, cacheScope: "private" }, - } - stdout_write.puts(JSON.generate(response)) - stdout_write.flush - end - - # No prior `connect`: `server/discover` (SEP-2575) is sessionless discovery. - response = transport.send_request(request: { jsonrpc: "2.0", id: "d1", method: "server/discover" }) - - assert_equal(["2026-07-28"], response.dig("result", "supportedVersions")) - refute_predicate(transport, :connected?) - ensure - server_thread&.join - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io| - io.close unless io.closed? - end - end - - def test_connect_modern_probes_discover_and_stamps_requests - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - received = [] - server_thread = Thread.new do - discover_request = JSON.parse(stdin_read.gets) - received << discover_request - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: discover_request["id"], - result: { - supportedVersions: ["2026-07-28"], - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0" }, - ttlMs: 0, - cacheScope: "private", - }, - })) - stdout_write.flush - - tools_request = JSON.parse(stdin_read.gets) - received << tools_request - stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: tools_request["id"], result: { tools: [] } })) - stdout_write.flush - end - - result = transport.connect(mode: :modern, client_info: { name: "my-app", version: "9.9" }) - response = transport.send_request(request: { jsonrpc: "2.0", id: "t1", method: "tools/list" }) - - assert_equal(["2026-07-28"], result["supportedVersions"]) - assert_predicate(transport, :modern?) - assert_predicate(transport, :connected?) - assert_equal("2026-07-28", transport.protocol_version) - assert_equal("t1", response["id"]) - - # No `initialize` was sent; both frames carry the SEP-2575 envelope. - assert_equal(["server/discover", "tools/list"], received.map { |frame| frame["method"] }) - triple = received[1].dig("params", "_meta") - assert_equal("2026-07-28", triple["io.modelcontextprotocol/protocolVersion"]) - assert_equal({ "name" => "my-app", "version" => "9.9" }, triple["io.modelcontextprotocol/clientInfo"]) - assert_equal({}, triple["io.modelcontextprotocol/clientCapabilities"]) - ensure - server_thread&.join - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io| - io.close unless io.closed? - end - end - - def test_connect_modern_warns_for_deprecated_capabilities - # SEP-2577 deprecates roots and sampling at 2026-07-28, the revision every modern connection speaks. - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - discover_request = JSON.parse(stdin_read.gets) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: discover_request["id"], - result: { - supportedVersions: ["2026-07-28"], - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0" }, - ttlMs: 0, - cacheScope: "private", - }, - })) - stdout_write.flush - end - - assert_deprecation_warning(/MCP Roots .*2026-07-28.*MCP Sampling .*2026-07-28/m) do - transport.connect(mode: :modern, capabilities: { roots: { listChanged: true }, sampling: {} }) - end - - assert_predicate(transport, :modern?) - ensure - server_thread&.join - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io| - io.close unless io.closed? - end - end - - def test_connect_auto_falls_back_to_the_legacy_handshake - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - - server_thread = Thread.new do - discover_request = JSON.parse(stdin_read.gets) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: discover_request["id"], - error: { code: -32601, message: "Method not found" }, - })) - stdout_write.flush - - init_request = JSON.parse(stdin_read.gets) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0" }, - }, - })) - stdout_write.flush - - # `notifications/initialized` - stdin_read.gets - end - - result = transport.connect(mode: :auto) - - assert_equal("2025-11-25", result["protocolVersion"]) - assert_equal("2025-11-25", transport.protocol_version) - refute_predicate(transport, :modern?) - assert_predicate(transport, :connected?) - ensure - server_thread&.join - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io| - io.close unless io.closed? - end - end - - def test_connect_auto_bounds_the_discover_probe_when_no_read_timeout_is_configured - transport = Stdio.new(command: "ruby", args: ["server.rb"]) - transport.stubs(:start) - - observed_timeout = nil - transport.define_singleton_method(:probe_discover) do - observed_timeout = @read_timeout - raise RequestHandlerError.new("probe timed out", {}, error_type: :internal_error) - end - transport.define_singleton_method(:connect_legacy) do |**| - { "protocolVersion" => "2025-11-25" } - end - - result = transport.connect(mode: :auto) - - assert_equal(Stdio::DEFAULT_DISCOVER_PROBE_TIMEOUT, observed_timeout) - assert_nil(transport.instance_variable_get(:@read_timeout)) - assert_equal("2025-11-25", result["protocolVersion"]) - end - - def test_connect_auto_falls_back_when_the_server_never_answers_the_probe - stdin_read, stdin_write = IO.pipe - stdout_read, stdout_write = IO.pipe - stderr_read, _ = IO.pipe - - Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread]) - # A configured `read_timeout` also bounds the probe; the server below reads - # the `server/discover` request and never responds, which must count as - # legacy evidence instead of blocking `connect` forever. - transport = Stdio.new(command: "ruby", args: ["server.rb"], read_timeout: 0.05) - - server_thread = Thread.new do - # Silently swallow the probe. - stdin_read.gets - - init_request = JSON.parse(stdin_read.gets) - stdout_write.puts(JSON.generate({ - jsonrpc: "2.0", - id: init_request["id"], - result: { - protocolVersion: "2025-11-25", - capabilities: {}, - serverInfo: { name: "test-server", version: "1.0" }, - }, - })) - stdout_write.flush - - # `notifications/initialized` - stdin_read.gets - end - - result = transport.connect(mode: :auto) - - assert_equal("2025-11-25", result["protocolVersion"]) - refute_predicate(transport, :modern?) - ensure - server_thread&.join - [stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io| - io.close unless io.closed? - end - end - - def mock_wait_thread - thread = mock("wait_thread") - thread.stubs(:alive?).returns(true) - thread.stubs(:value).returns(nil) - thread - end - end - end -end diff --git a/test/mcp/client/tool_test.rb b/test/mcp/client/tool_test.rb index f2025ab..88e82e9 100644 --- a/test/mcp/client/tool_test.rb +++ b/test/mcp/client/tool_test.rb @@ -33,24 +33,6 @@ module MCP assert_nil(@tool.output_schema) end - def test_annotations_returns_nil_when_not_provided - assert_nil(@tool.annotations) - end - - def test_annotations_returns_annotations_when_provided - tool_with_annotations = Tool.new( - name: "test_tool_with_annotations", - description: "A test tool with annotations", - input_schema: { "type" => "object" }, - annotations: { "readOnlyHint" => true, "title" => "Test Tool" }, - ) - - assert_equal( - { "readOnlyHint" => true, "title" => "Test Tool" }, - tool_with_annotations.annotations, - ) - end - def test_output_schema_returns_output_schema_when_provided tool_with_output = Tool.new( name: "test_tool_with_output", @@ -71,14 +53,12 @@ module MCP description: "A tool with all parameters", input_schema: { "type" => "object" }, output_schema: { "type" => "object", "properties" => { "status" => { "type" => "boolean" } } }, - annotations: { "readOnlyHint" => true }, ) assert_equal("full_tool", tool.name) assert_equal("A tool with all parameters", tool.description) assert_equal({ "type" => "object" }, tool.input_schema) assert_equal({ "type" => "object", "properties" => { "status" => { "type" => "boolean" } } }, tool.output_schema) - assert_equal({ "readOnlyHint" => true }, tool.annotations) end end end diff --git a/test/mcp/client_test.rb b/test/mcp/client_test.rb index bbd0652..168ed94 100644 --- a/test/mcp/client_test.rb +++ b/test/mcp/client_test.rb @@ -5,342 +5,12 @@ require "securerandom" module MCP class ClientTest < Minitest::Test - def test_connect_delegates_to_transport_and_forwards_keyword_args - transport = mock - init_result = { - "protocolVersion" => "2025-11-25", - "capabilities" => { "tools" => {} }, - "serverInfo" => { "name" => "test-server", "version" => "1.0" }, - } - transport.expects(:connect).with( - client_info: { name: "my-app", version: "1.0" }, - protocol_version: "2025-11-25", - capabilities: { roots: {} }, - ).returns(init_result).once - - result = Client.new(transport: transport).connect( - client_info: { name: "my-app", version: "1.0" }, - protocol_version: "2025-11-25", - capabilities: { roots: {} }, - ) - - assert_equal(init_result, result) - end - - def test_connect_passes_nil_defaults_to_transport - transport = mock - transport.expects(:connect) - .with(client_info: nil, protocol_version: nil, capabilities: {}) - .returns({ "protocolVersion" => "2025-11-25" }).once - - Client.new(transport: transport).connect - end - - def test_connect_is_noop_when_transport_does_not_respond_to_connect - transport = mock - transport.stubs(:respond_to?).with(:connect).returns(false) - transport.stubs(:respond_to?).with(:server_info).returns(false) - - client = Client.new(transport: transport) - - assert_nil(client.connect) - assert_nil(client.server_info) - end - - def test_on_elicitation_registers_handler_on_transport - transport = mock - handler = proc { { action: "accept", content: {} } } - transport.expects(:on_server_request).with("elicitation/create") - - Client.new(transport: transport).on_elicitation(&handler) - end - - def test_on_elicitation_is_accepted_when_transport_does_not_support_server_requests - # The handler still answers embedded `elicitation/create` requests of SEP-2322 `input_required` results, - # which need no server-to-client route. Refusing to register it would lock stdio clients, - # and every modern-lifecycle connection, out of the only way the spec leaves for asking. - transport = mock - transport.stubs(:respond_to?).with(:on_server_request).returns(false) - - Client.new(transport: transport).on_elicitation { { action: "accept", content: {} } } - end - - def test_on_sampling_registers_handler_on_transport - transport = mock - handler = proc { { role: "assistant", content: { type: "text", text: "hi" } } } - transport.expects(:on_server_request).with("sampling/createMessage") - - Client.new(transport: transport).on_sampling(&handler) - end - - def test_on_sampling_is_accepted_when_transport_does_not_support_server_requests - transport = mock - transport.stubs(:respond_to?).with(:on_server_request).returns(false) - - Client.new(transport: transport).on_sampling { { role: "assistant", content: { type: "text", text: "hi" } } } - end - - def test_on_roots_registers_handler_on_transport - transport = mock - handler = proc { { roots: [{ uri: "file:///project", name: "Project" }] } } - transport.expects(:on_server_request).with("roots/list") - - Client.new(transport: transport).on_roots(&handler) - end - - # A transport that declares `mode:` on `connect`, recording what it received. - # The `:not_forwarded` sentinel distinguishes "Client did not forward mode" from - # "Client forwarded mode: :legacy". - class ModeAwareTransport - attr_reader :received - - def connect(client_info: nil, protocol_version: nil, capabilities: {}, mode: :not_forwarded) - @received = { - client_info: client_info, - protocol_version: protocol_version, - capabilities: capabilities, - mode: mode, - } - { "supportedVersions" => ["2026-07-28"] } - end - end - - def test_connect_defaults_to_auto_on_transports_declaring_mode - transport = ModeAwareTransport.new - - Client.new(transport: transport).connect - - assert_equal(:auto, transport.received[:mode]) - end - - def test_connect_keeps_the_legacy_call_shape_for_transports_without_mode - # Custom transports whose `connect` does not declare `mode:` keep receiving - # the historical call shape, so the `:auto` default cannot break them. - transport = mock - transport.expects(:connect).with( - client_info: nil, protocol_version: nil, capabilities: {}, - ).returns({ "protocolVersion" => "2025-11-25" }).once - - Client.new(transport: transport).connect - end - - def test_connect_routes_explicit_legacy_through_the_legacy_call_shape - transport = ModeAwareTransport.new - - Client.new(transport: transport).connect(mode: :legacy) - - assert_equal(:not_forwarded, transport.received[:mode]) - end - - def test_connect_pins_legacy_for_an_explicit_stable_protocol_version - # An explicitly requested legacy-generation version must never be overridden - # by the default negotiation adopting the modern lifecycle. - transport = ModeAwareTransport.new - - Client.new(transport: transport).connect(protocol_version: "2025-11-25") - - assert_equal(:not_forwarded, transport.received[:mode]) - assert_equal("2025-11-25", transport.received[:protocol_version]) - end - - def test_connect_negotiates_automatically_for_an_explicit_modern_protocol_version - transport = ModeAwareTransport.new - - Client.new(transport: transport).connect(protocol_version: "2026-07-28") - - assert_equal(:auto, transport.received[:mode]) - end - - def test_connect_raises_for_explicit_non_legacy_mode_on_a_transport_without_mode - transport = mock - transport.expects(:connect).never - - error = assert_raises(ArgumentError) do - Client.new(transport: transport).connect(mode: :modern) - end - - assert_includes(error.message, "does not support mode:") - end - - def test_connect_rejects_unknown_modes - transport = ModeAwareTransport.new - - assert_raises(ArgumentError) do - Client.new(transport: transport).connect(mode: :bogus) - end - end - - def test_discover_returns_a_discover_result - transport = mock - transport.expects(:send_request).with do |args| - args[:request][:method] == "server/discover" - end.returns({ - "result" => { - "supportedVersions" => ["2026-07-28"], - "capabilities" => { "tools" => {} }, - "_meta" => { "io.modelcontextprotocol/serverInfo" => { "name" => "test-server", "version" => "1.0" } }, - "instructions" => "Optional instructions", - "ttlMs" => 3_600_000, - "cacheScope" => "public", - }, - }).once - - result = Client.new(transport: transport).discover - - assert_equal(["2026-07-28"], result.supported_versions) - assert_equal({ "tools" => {} }, result.capabilities) - assert_equal({ "name" => "test-server", "version" => "1.0" }, result.server_info) - assert_equal("Optional instructions", result.instructions) - assert_equal(3_600_000, result.ttl_ms) - assert_equal("public", result.cache_scope) - end - - def test_discover_maps_a_top_level_server_info_as_a_fallback - # Servers built against the frozen SEP text still stamp `serverInfo` at the top level; - # the finalized spec moved it into the result `_meta`. - transport = mock - transport.expects(:send_request).returns({ - "result" => { - "supportedVersions" => ["2026-07-28"], - "serverInfo" => { "name" => "sep-era-server", "version" => "1.0" }, - }, - }).once - - result = Client.new(transport: transport).discover - - assert_equal({ "name" => "sep-era-server", "version" => "1.0" }, result.server_info) - end - - def test_discover_raises_validation_error_on_missing_result - transport = mock - transport.expects(:send_request).returns({}).once - - assert_raises(Client::ValidationError) do - Client.new(transport: transport).discover - end - end - - def test_discover_raises_server_error_on_jsonrpc_error - transport = mock - transport.expects(:send_request).returns({ - "error" => { "code" => -32601, "message" => "Method not found" }, - }).once - - error = assert_raises(Client::ServerError) do - Client.new(transport: transport).discover - end - - assert_equal(-32601, error.code) - end - - def test_era_independent_readers_on_a_legacy_result - transport = mock - transport.stubs(:server_info).returns({ - "protocolVersion" => "2025-11-25", - "capabilities" => { "tools" => {} }, - "serverInfo" => { "name" => "legacy-server", "version" => "1.0" }, - "instructions" => "Be helpful", - }) - - client = Client.new(transport: transport) - - assert_equal("2025-11-25", client.protocol_version) - assert_equal({ "tools" => {} }, client.server_capabilities) - assert_equal("Be helpful", client.instructions) - assert_equal({ "name" => "legacy-server", "version" => "1.0" }, client.server_implementation) - end - - def test_era_independent_readers_on_a_modern_result - # A modern `DiscoverResult` has no `protocolVersion`; the adopted version comes - # from the transport. `serverInfo` sits in the result `_meta` per the final spec. - transport = mock - transport.stubs(:protocol_version).returns("2026-07-28") - transport.stubs(:server_info).returns({ - "supportedVersions" => ["2026-07-28"], - "capabilities" => { "tools" => {} }, - "instructions" => "Be helpful", - "_meta" => { "io.modelcontextprotocol/serverInfo" => { "name" => "modern-server", "version" => "2.0" } }, - "ttlMs" => 0, - "cacheScope" => "private", - }) - - client = Client.new(transport: transport) - - assert_equal("2026-07-28", client.protocol_version) - assert_equal({ "tools" => {} }, client.server_capabilities) - assert_equal("Be helpful", client.instructions) - assert_equal({ "name" => "modern-server", "version" => "2.0" }, client.server_implementation) - end - - def test_server_implementation_falls_back_to_the_top_level_and_tolerates_absence - transport = mock - transport.stubs(:server_info).returns({ - "supportedVersions" => ["2026-07-28"], - "serverInfo" => { "name" => "top-level", "version" => "1.0" }, - }) - - assert_equal({ "name" => "top-level", "version" => "1.0" }, Client.new(transport: transport).server_implementation) - - anonymous = mock - anonymous.stubs(:server_info).returns({ "supportedVersions" => ["2026-07-28"] }) - - assert_nil(Client.new(transport: anonymous).server_implementation) - end - - def test_era_independent_readers_return_nil_before_connect - transport = mock - transport.stubs(:respond_to?).with(:server_info).returns(false) - transport.stubs(:respond_to?).with(:protocol_version).returns(false) - - client = Client.new(transport: transport) - - assert_nil(client.protocol_version) - assert_nil(client.server_capabilities) - assert_nil(client.instructions) - assert_nil(client.server_implementation) - end - - def test_connected_delegates_to_transport_when_supported - transport = mock - transport.expects(:connected?).returns(true) - - assert_predicate(Client.new(transport: transport), :connected?) - end - - def test_connected_returns_true_when_transport_does_not_respond_to_connected - transport = mock - transport.stubs(:respond_to?).with(:connected?).returns(false) - - assert_predicate(Client.new(transport: transport), :connected?) - end - - def test_server_info_delegates_to_transport_when_supported - transport = mock - init_result = { "protocolVersion" => "2025-11-25" } - transport.expects(:server_info).returns(init_result) - - assert_equal(init_result, Client.new(transport: transport).server_info) - end - - def test_server_info_returns_nil_when_transport_does_not_expose_it - transport = mock - transport.stubs(:respond_to?).with(:server_info).returns(false) - - assert_nil(Client.new(transport: transport).server_info) - end - def test_tools_sends_request_to_transport_and_returns_tools_array transport = mock mock_response = { "result" => { "tools" => [ - { - "name" => "tool1", - "description" => "tool1", - "inputSchema" => {}, - "outputSchema" => { "type" => "object", "properties" => { "result" => { "type" => "string" } } }, - "annotations" => { "readOnlyHint" => true, "title" => "Tool One" }, - }, + { "name" => "tool1", "description" => "tool1", "inputSchema" => {} }, { "name" => "tool2", "description" => "tool2", "inputSchema" => {} }, ], }, @@ -356,11 +26,7 @@ module MCP assert_equal(2, tools.size) assert_equal("tool1", tools.first.name) - assert_equal({ "type" => "object", "properties" => { "result" => { "type" => "string" } } }, tools.first.output_schema) - assert_equal({ "readOnlyHint" => true, "title" => "Tool One" }, tools.first.annotations) assert_equal("tool2", tools.last.name) - assert_nil(tools.last.output_schema) - assert_nil(tools.last.annotations) end def test_tools_returns_empty_array_when_no_tools @@ -375,63 +41,7 @@ module MCP client = Client.new(transport: transport) tools = client.tools - assert_equal([], tools) - end - - def test_tools_excludes_invalid_x_mcp_header_definitions_on_a_modern_connection - # SEP-2243: on the modern lifecycle a tool definition violating the `x-mcp-header` - # constraints MUST be excluded from `tools/list` results, with a warning naming the tool. - transport = mock - transport.stubs(:modern?).returns(true) - mock_response = { - "result" => { - "tools" => [ - { "name" => "valid_tool", "inputSchema" => { "type" => "object" } }, - { - "name" => "invalid_tool", - "inputSchema" => { - "type" => "object", - "properties" => { "value" => { "type" => "string", "x-mcp-header" => "bad name" } }, - }, - }, - ], - }, - } - transport.expects(:send_request).returns(mock_response).once - client = Client.new(transport: transport) - - # `rake` runs the suite with `-W0`, which silences `Kernel#warn`; restore warnings - # locally so the SHOULD-level warning is observable. - original_verbose = $VERBOSE - $VERBOSE = false - tools = nil - _out, warning = capture_io { tools = client.tools } - $VERBOSE = original_verbose - - assert_equal(["valid_tool"], tools.map(&:name)) - assert_includes(warning, "invalid_tool") - end - - def test_tools_keeps_invalid_x_mcp_header_definitions_on_a_legacy_connection - transport = mock - transport.stubs(:modern?).returns(false) - mock_response = { - "result" => { - "tools" => [ - { - "name" => "invalid_tool", - "inputSchema" => { - "type" => "object", - "properties" => { "value" => { "type" => "string", "x-mcp-header" => "bad name" } }, - }, - }, - ], - }, - } - transport.expects(:send_request).returns(mock_response).once - client = Client.new(transport: transport) - - assert_equal(["invalid_tool"], client.tools.map(&:name)) + assert_empty(tools) end def test_call_tool_sends_request_to_transport_and_returns_content @@ -457,293 +67,6 @@ module MCP assert_equal([{ type: "text", text: "Hello, world!" }], content) end - def test_call_tool_by_name - transport = mock - arguments = { foo: "bar" } - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :params, :name) == "tool1" && - args.dig(:request, :params, :arguments) == arguments - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.call_tool(name: "tool1", arguments: arguments) - content = result.dig("result", "content") - - assert_equal([{ type: "text", text: "Hello, world!" }], content) - end - - def test_call_tool_raises_input_required_error_when_result_type_is_input_required - # Per SEP-2322, a result with `resultType: "input_required"` is not a final result; - # surface it instead of returning it as a normal result. - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - mock_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { - "1" => { "method" => "elicitation/create", "params" => { "mode" => "form", "message" => "Name?" } }, - }, - "requestState" => "opaque-state", - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::InputRequiredError) do - client.call_tool(tool: tool, arguments: {}) - end - - assert_equal( - { "1" => { "method" => "elicitation/create", "params" => { "mode" => "form", "message" => "Name?" } } }, - error.input_requests, - ) - assert_equal("opaque-state", error.request_state) - assert_equal(mock_response["result"], error.result) - end - - def test_call_tool_returns_normally_when_result_type_is_complete - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - mock_response = { - "result" => { - "resultType" => "complete", - "content" => [{ "type" => "text", "text" => "done" }], - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.call_tool(tool: tool, arguments: {}) - - assert_equal("done", result.dig("result", "content", 0, "text")) - end - - def test_call_tool_returns_normally_when_result_type_is_absent - # Regression guard: stable-protocol servers never send `resultType`. - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - mock_response = { - "result" => { "content" => [{ "type" => "text", "text" => "done" }] }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.call_tool(tool: tool, arguments: {}) - - assert_equal("done", result.dig("result", "content", 0, "text")) - end - - def test_list_tools_raises_input_required_error_for_input_required_results - # The recognition lives in the shared request path, so every client method is covered, not only tools/call. - transport = mock - mock_response = { - "result" => { "resultType" => "input_required", "inputRequests" => {} }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - assert_raises(Client::InputRequiredError) { client.list_tools } - end - - def test_call_tool_drives_the_input_required_loop_with_a_configured_handler - transport = mock - sent_requests = [] - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { - "region" => { "method" => "elicitation/create", "params" => { "message" => "Which region?" } }, - }, - "requestState" => "state-1", - }, - } - final_response = { "result" => { "content" => [{ "type" => "text", "text" => "done" }] } } - transport.expects(:send_request).twice.with do |args| - sent_requests << args[:request] - true - end.returns(input_required_response, final_response) - - handled_params = nil - client = Client.new(transport: transport) - client.on_elicitation do |params| - handled_params = params - { action: "accept", content: { value: "us-east-1" } } - end - - response = client.call_tool(name: "my_tool", arguments: { city: "Tokyo" }) - - assert_equal("done", response.dig("result", "content", 0, "text")) - assert_equal({ "message" => "Which region?" }, handled_params) - - first_leg, retry_leg = sent_requests - # The ORIGINAL params are preserved; the answers ride under the same keys with - # the byte-exact `requestState` echo, on a fresh JSON-RPC id. - assert_equal("my_tool", retry_leg.dig(:params, :name)) - assert_equal({ city: "Tokyo" }, retry_leg.dig(:params, :arguments)) - assert_equal( - { "region" => { action: "accept", content: { value: "us-east-1" } } }, - retry_leg.dig(:params, :inputResponses), - ) - assert_equal("state-1", retry_leg.dig(:params, :requestState)) - refute_equal(first_leg[:id], retry_leg[:id]) - end - - def test_input_required_loop_backs_off_on_request_state_only_legs - transport = mock - state_only_response = { - "result" => { "resultType" => "input_required", "requestState" => "busy-state" }, - } - final_response = { "result" => { "content" => [] } } - transport.stubs(:send_request).returns(state_only_response, state_only_response, final_response) - - client = Client.new(transport: transport) - client.on_elicitation { |_params| {} } - slept = [] - client.stubs(:sleep).with { |seconds| slept << seconds } - - response = client.call_tool(name: "my_tool") - - assert_equal(final_response, response) - - # Exponential from 50ms, matching the Python SDK. - assert_equal([0.05, 0.1], slept) - end - - def test_input_required_loop_raises_after_max_rounds - transport = mock - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { "q" => { "method" => "elicitation/create", "params" => {} } }, - "requestState" => "state-1", - }, - } - transport.stubs(:send_request).returns(input_required_response) - - client = Client.new(transport: transport, input_required_max_rounds: 2) - client.on_elicitation { |_params| { action: "decline" } } - - error = assert_raises(Client::InputRequiredError) { client.call_tool(name: "my_tool") } - - assert_includes(error.message, "after 2 rounds") - assert_equal("state-1", error.request_state) - end - - def test_input_required_loop_falls_back_to_the_error_for_unhandled_request_kinds - transport = mock - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { "llm" => { "method" => "sampling/createMessage", "params" => {} } }, - "requestState" => "state-1", - }, - } - transport.expects(:send_request).returns(input_required_response).once - - client = Client.new(transport: transport) - client.on_elicitation { |_params| {} } - - error = assert_raises(Client::InputRequiredError) { client.call_tool(name: "my_tool") } - - assert_includes(error.message, "sampling/createMessage") - assert_equal("state-1", error.request_state) - end - - def test_input_required_loop_runs_on_a_transport_without_server_request_support - # The modern lifecycle forbids server-to-client requests, so an `input_required` result is the only - # way a server can ask. A transport with no `on_server_request` must still drive the loop. - transport = mock - transport.stubs(:respond_to?).with(:on_server_request).returns(false) - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { "q" => { "method" => "elicitation/create", "params" => { "message" => "Region?" } } }, - "requestState" => "state-1", - }, - } - final_response = { "result" => { "content" => [{ "text" => "done" }] } } - transport.expects(:send_request).twice.returns(input_required_response, final_response) - - client = Client.new(transport: transport) - client.on_elicitation { |_params| { action: "accept", content: { value: "us-east-1" } } } - - response = client.call_tool(name: "my_tool") - - assert_equal("done", response.dig("result", "content", 0, "text")) - end - - def test_input_required_loop_uses_a_roots_handler_registered_with_on_roots - transport = mock - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { "r" => { "method" => "roots/list" } }, - "requestState" => "state-1", - }, - } - final_response = { "result" => { "content" => [{ "text" => "done" }] } } - transport.expects(:on_server_request).with("roots/list") - transport.expects(:send_request).twice.returns(input_required_response, final_response) - - client = Client.new(transport: transport) - client.on_roots { |_params| { roots: [{ uri: "file:///project", name: "Project" }] } } - - response = client.call_tool(name: "my_tool") - - assert_equal("done", response.dig("result", "content", 0, "text")) - end - - def test_call_tool_sends_manual_retry_fields - transport = mock - transport.expects(:send_request).with do |args| - params = args[:request][:params] - params[:inputResponses] == { "region" => { action: "accept" } } && params[:requestState] == "state-1" && params[:name] == "my_tool" - end.returns({ "result" => { "content" => [] } }).once - - client = Client.new(transport: transport) - client.call_tool(name: "my_tool", input_responses: { "region" => { action: "accept" } }, request_state: "state-1") - end - - def test_get_prompt_drives_the_input_required_loop - transport = mock - input_required_response = { - "result" => { - "resultType" => "input_required", - "inputRequests" => { "q" => { "method" => "elicitation/create", "params" => { "message" => "?" } } }, - "requestState" => "prompt-state", - }, - } - final_response = { "result" => { "messages" => [] } } - sent_requests = [] - transport.expects(:send_request).twice.with do |args| - sent_requests << args[:request] - true - end.returns(input_required_response, final_response) - - client = Client.new(transport: transport) - client.on_elicitation { |_params| { action: "accept", content: {} } } - - result = client.get_prompt(name: "my_prompt") - - assert_equal({ "messages" => [] }, result) - assert_equal("prompt-state", sent_requests[1].dig(:params, :requestState)) - end - - def test_call_tool_raises_when_no_name_or_tool - client = Client.new(transport: mock) - - error = assert_raises(ArgumentError) { client.call_tool(arguments: { foo: "bar" }) } - assert_equal("Either `name:` or `tool:` must be provided.", error.message) - end - def test_resources_sends_request_to_transport_and_returns_resources_array transport = mock mock_response = { @@ -779,7 +102,7 @@ module MCP client = Client.new(transport: transport) resources = client.resources - assert_equal([], resources) + assert_empty(resources) end def test_read_resource_sends_request_to_transport_and_returns_contents @@ -819,44 +142,7 @@ module MCP client = Client.new(transport: transport) contents = client.read_resource(uri: uri) - assert_equal([], contents) - end - - def test_resource_templates_sends_request_to_transport_and_returns_resource_templates_array - transport = mock - mock_response = { - "result" => { - "resourceTemplates" => [ - { "name" => "template1", "uriTemplate" => "file:///path/{filename}", "description" => "First template" }, - { "name" => "template2", "uriTemplate" => "http://example.com/{id}", "description" => "Second template" }, - ], - }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "resources/templates/list" && args.dig(:request, :jsonrpc) == "2.0" - end.returns(mock_response).once - - client = Client.new(transport: transport) - resource_templates = client.resource_templates - - assert_equal(2, resource_templates.size) - assert_equal("template1", resource_templates.first["name"]) - assert_equal("file:///path/{filename}", resource_templates.first["uriTemplate"]) - assert_equal("template2", resource_templates.last["name"]) - assert_equal("http://example.com/{id}", resource_templates.last["uriTemplate"]) - end - - def test_resource_templates_returns_empty_array_when_no_resource_templates - transport = mock - mock_response = { "result" => { "resourceTemplates" => [] } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - resource_templates = client.resource_templates - - assert_equal([], resource_templates) + assert_empty(contents) end def test_prompts_sends_request_to_transport_and_returns_prompts_array @@ -921,7 +207,7 @@ module MCP client = Client.new(transport: transport) prompts = client.prompts - assert_equal([], prompts) + assert_empty(prompts) end def test_get_prompt_sends_request_to_transport_and_returns_contents @@ -967,7 +253,7 @@ module MCP client = Client.new(transport: transport) contents = client.get_prompt(name: name) - assert_equal({}, contents) + assert_empty(contents) end def test_get_prompt_returns_empty_hash @@ -980,1158 +266,7 @@ module MCP client = Client.new(transport: transport) contents = client.get_prompt(name: name) - assert_equal({}, contents) - end - - def test_call_tool_includes_meta_progress_token_when_provided - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - arguments = { foo: "bar" } - progress_token = "my-progress-token" - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "tools/call" && - args.dig(:request, :params, :_meta, :progressToken) == progress_token && - args.dig(:request, :params, :name) == "tool1" && - args.dig(:request, :params, :arguments) == arguments - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: arguments, progress_token: progress_token) - end - - def test_call_tool_sends_trace_context_meta_entries - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - meta = { - MCP::TraceContext::TRACEPARENT_META_KEY => "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01", - MCP::TraceContext::TRACESTATE_META_KEY => "vendor=value", - MCP::TraceContext::BAGGAGE_META_KEY => "userId=alice", - } - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - sent_meta = args.dig(:request, :params, :_meta) - sent_meta["traceparent"] == meta["traceparent"] && - sent_meta["tracestate"] == meta["tracestate"] && - sent_meta["baggage"] == meta["baggage"] - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: {}, meta: meta) - end - - def test_call_tool_merges_meta_with_progress_token_taking_precedence - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - meta = { "traceparent" => "00-trace-span-01", "progressToken" => "from-meta" } - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - sent_meta = args.dig(:request, :params, :_meta) - sent_meta["traceparent"] == "00-trace-span-01" && - sent_meta[:progressToken] == "explicit-token" && - !sent_meta.key?("progressToken") - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: {}, progress_token: "explicit-token", meta: meta) - end - - def test_call_tool_omits_meta_when_empty_meta_hash_given - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :params).key?(:_meta) == false - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: {}, meta: {}) - end - - def test_call_tool_does_not_mutate_caller_meta - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - meta = { "traceparent" => "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01" } - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: {}, progress_token: "t", meta: meta) - - assert_equal({ "traceparent" => "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01" }, meta) - end - - def test_read_resource_sends_meta_when_provided - transport = mock - traceparent = "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01" - mock_response = { "result" => { "contents" => [] } } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "resources/read" && - args.dig(:request, :params, :uri) == "file:///foo" && - args.dig(:request, :params, :_meta, :traceparent) == traceparent - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.read_resource(uri: "file:///foo", meta: { traceparent: traceparent }) - end - - def test_request_methods_send_meta_when_provided - # Per SEP-414, trace context should flow on every request, so the `meta:` keyword - # is available on all client request methods. - traceparent = "00-0af7651916cd43dd8448eb211c80319c-00f067aa0ba902b7-01" - meta = { traceparent: traceparent } - - [ - ["tools/list", { "tools" => [] }, ->(client) { client.list_tools(meta: meta) }], - ["resources/list", { "resources" => [] }, ->(client) { client.list_resources(meta: meta) }], - ["resources/templates/list", { "resourceTemplates" => [] }, ->(client) { client.list_resource_templates(meta: meta) }], - ["prompts/list", { "prompts" => [] }, ->(client) { client.list_prompts(meta: meta) }], - ["prompts/get", {}, ->(client) { client.get_prompt(name: "p", meta: meta) }], - [ - "completion/complete", - { "completion" => { "values" => [] } }, - ->(client) { - client.complete(ref: { type: "ref/prompt", name: "p" }, argument: { name: "a", value: "v" }, meta: meta) - }, - ], - ["ping", {}, ->(client) { client.ping(meta: meta) }], - ].each do |method, result, invoke| - transport = mock - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == method && - args.dig(:request, :params, :_meta, :traceparent) == traceparent - end.returns({ "result" => result }).once - - invoke.call(Client.new(transport: transport)) - end - end - - def test_request_methods_omit_meta_when_not_provided - # Wire-format regression: without `meta:`, list requests keep sending no `params` at all. - transport = mock - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "tools/list" && !args[:request].key?(:params) - end.returns({ "result" => { "tools" => [] } }).once - - Client.new(transport: transport).list_tools - end - - def test_call_tool_omits_meta_when_no_progress_token - transport = mock - tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {}) - arguments = { foo: "bar" } - mock_response = { - "result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "tools/call" && - args.dig(:request, :params, :name) == "tool1" && - args.dig(:request, :params).key?(:_meta) == false - end.returns(mock_response).once - - client = Client.new(transport: transport) - client.call_tool(tool: tool, arguments: arguments) - end - - def test_tools_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.tools } - assert_equal(-32_601, error.code) - assert_equal("Method not found", error.message) - end - - def test_resources_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_602, "message" => "Invalid params" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.resources } - assert_equal(-32_602, error.code) - end - - def test_read_resource_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_602, "message" => "Resource not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - assert_raises(Client::ServerError) { client.read_resource(uri: "file:///missing") } - end - - def test_read_resource_surfaces_resource_not_found_code_and_data - # Per SEP-2164, servers report unknown resource URIs with -32602 and - # the URI in the error `data`; the client must expose both unmodified. - transport = mock - mock_response = { - "error" => { - "code" => -32_602, - "message" => "Resource not found: file:///missing.txt", - "data" => { "uri" => "file:///missing.txt" }, - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.read_resource(uri: "file:///missing.txt") } - - assert_equal(-32_602, error.code) - assert_equal({ "uri" => "file:///missing.txt" }, error.data) - end - - def test_get_prompt_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_602, "message" => "Prompt not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - assert_raises(Client::ServerError) { client.get_prompt(name: "missing") } - end - - def test_prompts_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - assert_raises(Client::ServerError) { client.prompts } - end - - def test_resource_templates_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - assert_raises(Client::ServerError) { client.resource_templates } - end - - def test_call_tool_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_602, "message" => "Tool not found" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.call_tool(name: "missing") } - assert_equal(-32_602, error.code) - end - - def test_server_error_includes_data_field - transport = mock - mock_response = { - "error" => { "code" => -32_603, "message" => "Internal error", "data" => "extra details" }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.tools } - assert_equal("extra details", error.data) - end - - def test_complete_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_602, "message" => "Invalid params" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.complete(ref: { type: "ref/prompt", name: "missing" }, argument: { name: "arg", value: "" }) } - assert_equal(-32_602, error.code) - end - - def test_complete_sends_request_and_returns_completion_result - transport = mock - mock_response = { - "result" => { - "completion" => { - "values" => ["python", "pytorch"], - "hasMore" => false, - }, - }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "completion/complete" && - args.dig(:request, :jsonrpc) == "2.0" && - args.dig(:request, :params, :ref) == { type: "ref/prompt", name: "code_review" } && - args.dig(:request, :params, :argument) == { name: "language", value: "py" } && - !args.dig(:request, :params).key?(:context) - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.complete( - ref: { type: "ref/prompt", name: "code_review" }, - argument: { name: "language", value: "py" }, - ) - - assert_equal(["python", "pytorch"], result["values"]) - refute(result["hasMore"]) - end - - def test_complete_includes_context_when_provided - transport = mock - mock_response = { - "result" => { - "completion" => { - "values" => ["flask"], - "hasMore" => false, - }, - }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :params, :context) == { arguments: { language: "python" } } - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.complete( - ref: { type: "ref/prompt", name: "code_review" }, - argument: { name: "framework", value: "fla" }, - context: { arguments: { language: "python" } }, - ) - - assert_equal(["flask"], result["values"]) - end - - def test_complete_returns_default_when_result_is_missing - transport = mock - mock_response = { "result" => {} } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.complete( - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "" }, - ) - - assert_equal([], result["values"]) - refute(result["hasMore"]) - end - - def test_ping_sends_request_and_returns_empty_hash - transport = mock - mock_response = { "result" => {} } - - transport.expects(:send_request).with do |args| - req = args[:request] - req[:method] == "ping" && - req[:jsonrpc] == "2.0" && - !req.key?(:params) - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.ping - - assert_equal({}, result) - end - - def test_ping_raises_server_error_on_error_response - transport = mock - mock_response = { "error" => { "code" => -32_603, "message" => "Internal error" } } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ServerError) { client.ping } - assert_equal(-32_603, error.code) - assert_equal("Internal error", error.message) - end - - def test_ping_raises_validation_error_when_result_is_missing - transport = mock - mock_response = {} - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ValidationError) { client.ping } - assert_equal("Response validation failed: missing or invalid `result`", error.message) - end - - def test_ping_raises_validation_error_when_result_is_wrong_type - transport = mock - mock_response = { "result" => "ok" } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - error = assert_raises(Client::ValidationError) { client.ping } - assert_equal("Response validation failed: missing or invalid `result`", error.message) - end - - def test_ping_propagates_transport_errors - transport = mock - transport_error = StandardError.new("read timeout") - transport.expects(:send_request).raises(transport_error).once - - client = Client.new(transport: transport) - error = assert_raises(StandardError) { client.ping } - assert_equal("read timeout", error.message) - end - - def test_tools_auto_paginates_across_multiple_pages - transport = mock - - page1_response = { - "result" => { - "tools" => [{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} }], - "nextCursor" => "cursor1", - }, - } - page2_response = { - "result" => { - "tools" => [{ "name" => "tool2", "description" => "tool2", "inputSchema" => {} }], - }, - } - - call_count = 0 - transport.expects(:send_request).twice.with do |args| - call_count += 1 - req = args[:request] - if call_count == 1 - req[:method] == "tools/list" && req[:params].nil? - else - req[:method] == "tools/list" && req[:params] == { cursor: "cursor1" } - end - end.returns(page1_response).then.returns(page2_response) - - client = Client.new(transport: transport) - tools = client.tools - - assert_equal(2, tools.size) - assert_equal("tool1", tools[0].name) - assert_equal("tool2", tools[1].name) - end - - def test_list_tools_returns_single_page_with_cursor - transport = mock - - mock_response = { - "result" => { - "tools" => [{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} }], - "nextCursor" => "cursor1", - }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == "tools/list" - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.list_tools - - assert_equal(1, result.tools.size) - assert_equal("tool1", result.tools[0].name) - assert_equal("cursor1", result.next_cursor) - end - - def test_list_results_expose_ttl_ms_and_cache_scope - # SEP-2549 cache hints are surfaced on every paginated result struct. - [ - ["tools/list", "tools", :list_tools], - ["prompts/list", "prompts", :list_prompts], - ["resources/list", "resources", :list_resources], - ["resources/templates/list", "resourceTemplates", :list_resource_templates], - ].each do |method, items_key, client_method| - transport = mock - mock_response = { - "result" => { items_key => [], "ttlMs" => 5000, "cacheScope" => "private" }, - } - transport.expects(:send_request).with do |args| - args.dig(:request, :method) == method - end.returns(mock_response).once - - result = Client.new(transport: transport).public_send(client_method) - - assert_equal(5000, result.ttl_ms, "#{method} missing ttl_ms") - assert_equal("private", result.cache_scope, "#{method} missing cache_scope") - end - end - - def test_list_results_have_nil_cache_hints_when_server_omits_them - transport = mock - mock_response = { "result" => { "tools" => [] } } - transport.expects(:send_request).returns(mock_response).once - - result = Client.new(transport: transport).list_tools - - assert_nil(result.ttl_ms) - assert_nil(result.cache_scope) - end - - def test_list_tools_with_cursor_param - transport = mock - - mock_response = { - "result" => { - "tools" => [{ "name" => "tool2", "description" => "tool2", "inputSchema" => {} }], - }, - } - - transport.expects(:send_request).with do |args| - args.dig(:request, :params) == { cursor: "cursor1" } - end.returns(mock_response).once - - client = Client.new(transport: transport) - result = client.list_tools(cursor: "cursor1") - - assert_equal(1, result.tools.size) - assert_equal("tool2", result.tools[0].name) - assert_nil(result.next_cursor) - end - - def test_resources_auto_paginates_across_multiple_pages - transport = mock - - page1_response = { - "result" => { - "resources" => [{ "uri" => "https://a.invalid", "name" => "a" }], - "nextCursor" => "cursor1", - }, - } - page2_response = { - "result" => { - "resources" => [{ "uri" => "https://b.invalid", "name" => "b" }], - }, - } - - transport.expects(:send_request).twice.returns(page1_response).then.returns(page2_response) - - client = Client.new(transport: transport) - resources = client.resources - - assert_equal(2, resources.size) - assert_equal("a", resources[0]["name"]) - assert_equal("b", resources[1]["name"]) - end - - def test_list_resources_returns_single_page_with_cursor - transport = mock - - mock_response = { - "result" => { - "resources" => [{ "uri" => "https://a.invalid", "name" => "a" }], - "nextCursor" => "cursor1", - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.list_resources - - assert_equal(1, result.resources.size) - assert_equal("cursor1", result.next_cursor) - end - - def test_resource_templates_auto_paginates_across_multiple_pages - transport = mock - - page1_response = { - "result" => { - "resourceTemplates" => [{ "uriTemplate" => "https://a.invalid/{id}", "name" => "a" }], - "nextCursor" => "cursor1", - }, - } - page2_response = { - "result" => { - "resourceTemplates" => [{ "uriTemplate" => "https://b.invalid/{id}", "name" => "b" }], - }, - } - - transport.expects(:send_request).twice.returns(page1_response).then.returns(page2_response) - - client = Client.new(transport: transport) - templates = client.resource_templates - - assert_equal(2, templates.size) - assert_equal("a", templates[0]["name"]) - assert_equal("b", templates[1]["name"]) - end - - def test_list_resource_templates_returns_single_page_with_cursor - transport = mock - - mock_response = { - "result" => { - "resourceTemplates" => [{ "uriTemplate" => "https://a.invalid/{id}", "name" => "a" }], - "nextCursor" => "cursor1", - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.list_resource_templates - - assert_equal(1, result.resource_templates.size) - assert_equal("cursor1", result.next_cursor) - end - - def test_prompts_auto_paginates_across_multiple_pages - transport = mock - - page1_response = { - "result" => { - "prompts" => [{ "name" => "prompt_a", "description" => "A" }], - "nextCursor" => "cursor1", - }, - } - page2_response = { - "result" => { - "prompts" => [{ "name" => "prompt_b", "description" => "B" }], - }, - } - - transport.expects(:send_request).twice.returns(page1_response).then.returns(page2_response) - - client = Client.new(transport: transport) - prompts = client.prompts - - assert_equal(2, prompts.size) - assert_equal("prompt_a", prompts[0]["name"]) - assert_equal("prompt_b", prompts[1]["name"]) - end - - def test_tools_breaks_when_server_returns_same_cursor_repeatedly - transport = mock - - stuck_response = { - "result" => { - "tools" => [{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} }], - "nextCursor" => "stuck_cursor", - }, - } - - # If the server keeps returning the same cursor, the client must not loop forever. - # Expect at most 2 calls: the initial request (cursor=nil) and one retry (cursor="stuck_cursor") - # that detects the repeat and breaks out. - transport.expects(:send_request).twice.returns(stuck_response) - - client = Client.new(transport: transport) - tools = client.tools - - assert_equal(2, tools.size) - end - - def test_tools_raises_when_the_server_offers_more_pages_than_max_pages - transport = mock - - pages = (1..3).map do |n| - { - "result" => { - "tools" => [{ "name" => "tool#{n}", "description" => "tool#{n}", "inputSchema" => {} }], - "nextCursor" => "cursor#{n}", - }, - } - end - - # A fresh cursor on every response defeats the repeat guard, so only `max_pages` stops the walk. - transport.expects(:send_request).times(3).returns(*pages) - - client = Client.new(transport: transport, max_pages: 3) - - error = assert_raises(Client::PaginationLimitError) { client.tools } - assert_equal( - "Server returned more than 3 pages; pass a larger `max_pages:` to `MCP::Client.new` if this is expected.", - error.message, - ) - end - - def test_tools_returns_every_page_when_the_server_stops_exactly_at_max_pages - transport = mock - - page1 = { - "result" => { - "tools" => [{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} }], - "nextCursor" => "cursor1", - }, - } - page2 = { - "result" => { - "tools" => [{ "name" => "tool2", "description" => "tool2", "inputSchema" => {} }], - }, - } - - transport.expects(:send_request).twice.returns(page1, page2) - - client = Client.new(transport: transport, max_pages: 2) - tools = client.tools - - assert_equal(["tool1", "tool2"], tools.map(&:name)) - end - - def test_raises_argument_error_when_max_pages_is_not_positive - error = assert_raises(ArgumentError) { Client.new(transport: mock, max_pages: 0) } - - assert_equal("max_pages must be a positive Integer", error.message) - end - - def test_tools_breaks_when_server_cycles_between_cursors - transport = mock - - page_a = { - "result" => { - "tools" => [{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} }], - "nextCursor" => "A", - }, - } - page_b = { - "result" => { - "tools" => [{ "name" => "tool2", "description" => "tool2", "inputSchema" => {} }], - "nextCursor" => "B", - }, - } - # Server cycles A -> B -> A. Client must detect the revisited cursor and break. - page_a_again = { - "result" => { - "tools" => [{ "name" => "tool3", "description" => "tool3", "inputSchema" => {} }], - "nextCursor" => "A", - }, - } - - transport.expects(:send_request).times(3).returns(page_a, page_b, page_a_again) - - client = Client.new(transport: transport) - tools = client.tools - - assert_equal(3, tools.size) - assert_equal(["tool1", "tool2", "tool3"], tools.map(&:name)) - end - - def test_resources_breaks_when_server_returns_same_cursor_repeatedly - transport = mock - - stuck_response = { - "result" => { - "resources" => [{ "uri" => "https://a.invalid", "name" => "a" }], - "nextCursor" => "stuck_cursor", - }, - } - - transport.expects(:send_request).twice.returns(stuck_response) - - client = Client.new(transport: transport) - resources = client.resources - - assert_equal(2, resources.size) - end - - def test_resource_templates_breaks_when_server_returns_same_cursor_repeatedly - transport = mock - - stuck_response = { - "result" => { - "resourceTemplates" => [{ "uriTemplate" => "https://a.invalid/{id}", "name" => "a" }], - "nextCursor" => "stuck_cursor", - }, - } - - transport.expects(:send_request).twice.returns(stuck_response) - - client = Client.new(transport: transport) - templates = client.resource_templates - - assert_equal(2, templates.size) - end - - def test_prompts_breaks_when_server_returns_same_cursor_repeatedly - transport = mock - - stuck_response = { - "result" => { - "prompts" => [{ "name" => "prompt_a", "description" => "A" }], - "nextCursor" => "stuck_cursor", - }, - } - - transport.expects(:send_request).twice.returns(stuck_response) - - client = Client.new(transport: transport) - prompts = client.prompts - - assert_equal(2, prompts.size) - end - - def test_list_prompts_returns_single_page_with_cursor - transport = mock - - mock_response = { - "result" => { - "prompts" => [{ "name" => "prompt_a", "description" => "A" }], - "nextCursor" => "cursor1", - }, - } - - transport.expects(:send_request).returns(mock_response).once - - client = Client.new(transport: transport) - result = client.list_prompts - - assert_equal(1, result.prompts.size) - assert_equal("cursor1", result.next_cursor) - end - - def test_cancellation_without_reason_omits_reason_in_notification - # The token-driven cancel path must omit `reason` from the `notifications/cancelled` params - # when the token is cancelled without one. - sent = Queue.new - cancellation = MCP::Cancellation.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |**| - cancellation.cancel # no reason - { "result" => {} } - end - transport.define_singleton_method(:send_notification) do |notification:| - sent.push(notification) - nil - end - - client = Client.new(transport: transport) - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "slow", arguments: {}, cancellation: cancellation) - end - - notification = sent.pop - assert_equal(Methods::NOTIFICATIONS_CANCELLED, notification[:method]) - refute(notification[:params].key?(:reason)) - end - - def test_call_tool_with_cancellation_returns_response_when_no_cancel - transport = mock - transport.expects(:send_request).returns({ "result" => { "content" => [{ "type" => "text", "text" => "ok" }] } }).once - transport.stubs(:send_notification) # required for `cancellation:` capability check - - cancellation = MCP::Cancellation.new - client = Client.new(transport: transport) - - response = client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - - assert_equal("ok", response.dig("result", "content", 0, "text")) - end - - def test_call_tool_with_cancellation_already_cancelled_raises_without_sending - transport = mock - transport.expects(:send_request).never - transport.expects(:send_notification).never - - cancellation = MCP::Cancellation.new - cancellation.cancel(reason: "pre-cancelled") - - client = Client.new(transport: transport) - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - end - end - - def test_call_tool_with_cancellation_mid_flight_raises_and_sends_notification - cancellation = MCP::Cancellation.new - notification_queue = Queue.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |**| - # Cancel while the request is "in flight". - cancellation.cancel(reason: "user abort") - sleep(0.05) - { "result" => {} } - end - transport.define_singleton_method(:send_notification) do |notification:| - notification_queue.push(notification) - nil - end - - client = Client.new(transport: transport) - - error = assert_raises(MCP::CancelledError) do - client.call_tool(name: "slow", arguments: {}, cancellation: cancellation) - end - - assert_equal("user abort", error.reason) - - # Cancel notification is dispatched fire-and-forget on a separate thread; - # block here until it reaches the transport. - notification = notification_queue.pop - assert_equal(Methods::NOTIFICATIONS_CANCELLED, notification[:method]) - assert_equal("user abort", notification[:params][:reason]) - end - - def test_loop_methods_accept_cancellation_keyword - # Regression: `tools` / `resources` / `resource_templates` / `prompts` are the high-level pagination loops. - # They must accept `cancellation:` so the README's "all request methods accept the cancellation: keyword" - # claim holds. The token is propagated to each underlying `list_*` page. - cancellation = MCP::Cancellation.new - - transport = mock - transport.stubs(:send_request).returns({ "result" => { "tools" => [] } }) - transport.stubs(:send_notification) # required for `cancellation:` capability check - - client = Client.new(transport: transport) - - [ - -> { client.tools(cancellation: cancellation) }, - -> { client.resources(cancellation: cancellation) }, - -> { client.resource_templates(cancellation: cancellation) }, - -> { client.prompts(cancellation: cancellation) }, - ].each do |loop_call| - transport.stubs(:send_request).returns({ "result" => {} }) - loop_call.call - end - end - - def test_cancel_callback_does_not_deadlock_when_transport_holds_a_mutex - # Regression: when the cancellation callback fires on the same thread that is currently inside - # `transport.send_request` (and therefore holds a transport-level mutex), a synchronous `send_notification` - # from the callback would deadlock by re-entering the same mutex. The fix wakes the calling thread first - # and dispatches the notification on a separate thread. - transport_mutex = Mutex.new - cancellation = MCP::Cancellation.new - - # Custom transport class so we can model a mutex held during send_request. - transport = Object.new - transport.define_singleton_method(:send_request) do |**| - transport_mutex.synchronize do - # Trigger cancel while we hold the mutex. The callback must NOT try to synchronously acquire - # the same mutex via send_notification. - cancellation.cancel(reason: "mid-flight") - # Hold the mutex briefly to give the callback time to (incorrectly) try to re-enter. - sleep(0.05) - { "result" => {} } - end - end - - # send_notification also needs the mutex - this is the path that would deadlock under synchronous dispatch. - send_notification_called = Queue.new - transport.define_singleton_method(:send_notification) do |notification:| - transport_mutex.synchronize do - send_notification_called.push(notification) - end - end - - client = Client.new(transport: transport) - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - end - - # The notification must reach the transport eventually (after the mutex is released by the now-finished send_request). - notification = send_notification_called.pop - assert_equal(Methods::NOTIFICATIONS_CANCELLED, notification[:method]) - assert_equal("mid-flight", notification[:params][:reason]) - end - - def test_late_cancel_after_response_does_not_send_stray_notification - # Regression: between the worker thread pushing `:response` and the main thread leaving `dispatch_with_cancellation`, - # a cancellation firing in that gap must not emit a stray `notifications/cancelled` for the already-completed request. - # The completion-mutex gate makes the worker and the on_cancel callback fight for a single slot; whichever sets - # `completed` first wins, the loser bails. - cancellation = MCP::Cancellation.new - notification_count = 0 - notification_count_mutex = Mutex.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |**, &on_sent| - on_sent&.call - { "result" => {} } - end - transport.define_singleton_method(:send_notification) do |**| - notification_count_mutex.synchronize { notification_count += 1 } - nil - end - - client = Client.new(transport: transport) - response = client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - - assert_equal({}, response["result"]) - - # Cancel after the call returned. The on_cancel hook was deregistered in the `ensure` block; - # even if a callback raced with the response handoff, `completed` would already be true and - # `queue.push :cancelled` plus the cancel-dispatch thread would not run. - cancellation.cancel(reason: "late") - - sleep(0.05) # let any erroneous cancel-dispatch thread complete. - - count = notification_count_mutex.synchronize { notification_count } - assert_equal(0, count, "no stray notifications/cancelled for an already-completed request") - end - - def test_call_tool_with_cancellation_raises_NoMethodError_when_transport_lacks_send_notification - # Regression: a transport that only implements `send_request` cannot deliver `notifications/cancelled`. - # We must surface this upfront with a clear `NoMethodError` rather than silently swallow - # the failure inside the cancel-dispatch thread - otherwise the user sees `CancelledError` but - # the server never receives the notification. - transport = Object.new - transport.define_singleton_method(:send_request) do |**| - { "result" => {} } - end - # NOTE: no send_notification. - - cancellation = MCP::Cancellation.new - client = Client.new(transport: transport) - - error = assert_raises(NoMethodError) do - client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - end - - assert_match(/send_notification/, error.message) - end - - def test_cancel_notification_is_dispatched_after_request_write_via_on_sent_block - # Regression for the wire-order race: a transport that yields from `send_request` after writing - # the request must see `:request` recorded before `:cancel` even when the cancel signal arrives concurrently. - recorded = [] - recorded_mutex = Mutex.new - cancellation = MCP::Cancellation.new - cancel_complete = Queue.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |request:, &on_sent| - # Trigger cancel BEFORE the simulated wire-write so the cancel-dispatch thread starts racing immediately. - # The `on_sent` block is yielded only after we have recorded the request - so any cancel-write that obeys - # the block must land afterwards. - cancellation.cancel(reason: "race") - sleep(0.02) # give cancel-dispatch thread time to spawn and start waiting - recorded_mutex.synchronize { recorded << [:request, request[:id]] } - on_sent&.call - { "result" => {} } - end - transport.define_singleton_method(:send_notification) do |notification:| - recorded_mutex.synchronize { recorded << [:cancel, notification[:params][:requestId]] } - cancel_complete.push(:done) - nil - end - - client = Client.new(transport: transport) - client.stubs(:generate_request_id).returns("req-A") - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "slow", arguments: {}, cancellation: cancellation) - end - - cancel_complete.pop # wait for the fire-and-forget cancel dispatch - - # Wire-order must be: request first, then cancel. - assert_equal([[:request, "req-A"], [:cancel, "req-A"]], recorded) - end - - def test_cancel_notification_waits_for_delayed_on_sent_signal - # Regression: the cancel-dispatch thread must wait for `&on_sent` no matter how long it takes - - # it cannot fall back to wall-clock-based timeout. An earlier 100 ms fixed-duration fallback - # could release the cancel thread before the worker reached its send-boundary at all, allowing - # the cancel to be issued without any prior request commitment - which the spec only covers under - # the receiver's MAY-ignore-unknown-id clause. The wait is now bounded by worker termination - # (via `ensure -> signal_sent.call`), not by elapsed time. - recorded = [] - recorded_mutex = Mutex.new - cancellation = MCP::Cancellation.new - cancel_complete = Queue.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |request:, &on_sent| - cancellation.cancel(reason: "race") - # Delay well beyond any plausible fixed-duration fallback (200 ms). - # If cancel-dispatch fires on a timer rather than waiting for on_sent, - # the recorded order will be [:cancel, :request] and the assertion below will fail. - sleep(0.2) - recorded_mutex.synchronize { recorded << [:request, request[:id]] } - on_sent&.call - { "result" => {} } - end - transport.define_singleton_method(:send_notification) do |notification:| - recorded_mutex.synchronize { recorded << [:cancel, notification[:params][:requestId]] } - cancel_complete.push(:done) - nil - end - - client = Client.new(transport: transport) - client.stubs(:generate_request_id).returns("req-D") - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "slow", arguments: {}, cancellation: cancellation) - end - - cancel_complete.pop - - assert_equal([[:request, "req-D"], [:cancel, "req-D"]], recorded) - end - - def test_cancel_notification_dispatches_when_worker_raises_before_on_sent - # Regression: if the worker raises before `&on_sent` is called - which can happen if a transport rejects - # a malformed request synchronously - the cancel-dispatch thread must still terminate AND deliver the notification. - # The worker's `ensure` block invokes `signal_sent.call`, which broadcasts to the condition variable and unblocks - # the `until request_sent` wait. Without the ensure-driven unblock, the dispatch thread would leak. - cancellation = MCP::Cancellation.new - send_notification_called = Queue.new - - transport = Object.new - transport.define_singleton_method(:send_request) do |**| - # Trigger cancel before raising so the cancel hook fires while the worker is mid-flight, - # then bail out without ever calling on_sent. - cancellation.cancel(reason: "race") - raise StandardError, "transport boom" - end - transport.define_singleton_method(:send_notification) do |notification:| - send_notification_called.push(notification) - nil - end - - client = Client.new(transport: transport) - client.stubs(:generate_request_id).returns("req-E") - - assert_raises(MCP::CancelledError) do - client.call_tool(name: "slow", arguments: {}, cancellation: cancellation) - end - - # The cancel-dispatch thread should still send the notification because the worker's `ensure` triggers `signal_sent.call`. - notification = send_notification_called.pop - assert_equal("req-E", notification[:params][:requestId]) - end - - def test_call_tool_with_cancellation_normal_completion_does_not_send_notification - transport = mock - transport.expects(:send_request).returns({ "result" => {} }).once - transport.expects(:send_notification).never - - cancellation = MCP::Cancellation.new - client = Client.new(transport: transport) - - client.call_tool(name: "noop", arguments: {}, cancellation: cancellation) - - # Late cancel after normal completion: hook should already be deregistered. - cancellation.cancel(reason: "late") + assert_empty(contents) end end end diff --git a/test/mcp/configuration_test.rb b/test/mcp/configuration_test.rb index 058bc19..afd1c0f 100644 --- a/test/mcp/configuration_test.rb +++ b/test/mcp/configuration_test.rb @@ -36,21 +36,15 @@ module MCP assert_equal test_context, reported_context end + # https://github.com/modelcontextprotocol/modelcontextprotocol/blob/14ec41c/schema/draft/schema.ts#L15 test "initializes with default protocol version" do - # The unset pin reads as the version the handshake settles on, which is also the only kind of - # value the writer accepts: reading back a version that cannot be set again would break code - # that round-trips the setting. config = Configuration.new - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, config.protocol_version - refute_predicate config, :protocol_version? - assert_nothing_raised { Configuration.new(protocol_version: config.protocol_version) } + assert_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, config.protocol_version end - test "uses the default protocol version when protocol_version is set to nil" do + test "uses the draft protocol version when protocol_version is set to nil" do config = Configuration.new(protocol_version: nil) - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, config.protocol_version + assert_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, config.protocol_version end test "raises ArgumentError when setting the draft protocol version" do @@ -72,29 +66,6 @@ module MCP assert_equal("protocol_version must be 2025-11-25, 2025-06-18, 2025-03-26, or 2024-11-05", exception.message) end - test "exposes the SEP-2575 modern protocol versions" do - assert_equal "2026-07-28", Configuration::LATEST_MODERN_PROTOCOL_VERSION - assert_equal ["2026-07-28"], Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS - assert Configuration.modern_protocol_version?("2026-07-28") - refute Configuration.modern_protocol_version?("2025-11-25") - end - - test "rejects a modern version as the protocol version pin" do - # The pin scopes the `initialize` handshake; a modern version has no handshake to pin - # (its version rides every request in `_meta`), so accepting it would configure nothing. - # The message names that reason instead of listing the accepted values, because this is - # the error an upgrade from a release that accepted the value lands on. - exception = assert_raises(ArgumentError) do - Configuration.new(protocol_version: Configuration::LATEST_MODERN_PROTOCOL_VERSION) - end - - assert_includes(exception.message, "is a modern protocol version and cannot be pinned here") - assert_includes(exception.message, "remove the setting") - - config = Configuration.new - assert_raises(ArgumentError) { config.protocol_version = "2026-07-28" } - end - test "raises ArgumentError when protocol_version is not a boolean value" do config = Configuration.new exception = assert_raises(ArgumentError) do @@ -103,14 +74,6 @@ module MCP assert_equal("validate_tool_call_arguments must be a boolean", exception.message) end - test "raises ArgumentError when validate_tool_call_results is not a boolean value" do - config = Configuration.new - exception = assert_raises(ArgumentError) do - config.validate_tool_call_results = "true" - end - assert_equal("validate_tool_call_results must be a boolean", exception.message) - end - test "merges protocol version from other configuration" do config1 = Configuration.new(protocol_version: "2025-03-26") config2 = Configuration.new(protocol_version: "2025-06-18") @@ -160,116 +123,6 @@ module MCP refute merged.validate_tool_call_arguments end - test "defaults instrument_server_context to false" do - config = Configuration.new - - refute_predicate config, :instrument_server_context? - end - - test "accepts instrument_server_context in the constructor" do - config = Configuration.new(instrument_server_context: true) - - assert_predicate config, :instrument_server_context? - end - - test "raises ArgumentError when instrument_server_context is not a boolean value" do - config = Configuration.new - - exception = assert_raises(ArgumentError) do - config.instrument_server_context = "true" - end - assert_equal("instrument_server_context must be a boolean", exception.message) - end - - test "merge carries instrument_server_context from the other configuration" do - base = Configuration.new(instrument_server_context: true) - other = Configuration.new(instrument_server_context: false) - - refute_predicate base.merge(other), :instrument_server_context? - assert_predicate other.merge(base), :instrument_server_context? - end - - test "defaults validate_tool_call_results to false" do - config = Configuration.new - refute config.validate_tool_call_results - end - - test "can set validate_tool_call_results to true" do - config = Configuration.new(validate_tool_call_results: true) - assert config.validate_tool_call_results - end - - test "validate_tool_call_results? returns false when not set" do - config = Configuration.new - refute config.validate_tool_call_results? - end - - test "validate_tool_call_results? returns true when set" do - config = Configuration.new(validate_tool_call_results: true) - assert config.validate_tool_call_results? - end - - test "merge preserves validate_tool_call_results from other config" do - config1 = Configuration.new(validate_tool_call_results: true) - config2 = Configuration.new - merged = config1.merge(config2) - refute merged.validate_tool_call_results? - end - - test "merge preserves validate_tool_call_results from self when other set" do - config1 = Configuration.new(validate_tool_call_results: true) - config2 = Configuration.new - merged = config2.merge(config1) - assert merged.validate_tool_call_results - end - - test "initializes with a default pass-through around_request" do - config = Configuration.new - called = false - config.around_request.call({}) { called = true } - assert called - end - - test "allows setting a custom around_request" do - config = Configuration.new - call_log = [] - config.around_request = ->(_data, &request_handler) { - call_log << :before - request_handler.call - call_log << :after - } - - config.around_request.call({}) { call_log << :execute } - assert_equal([:before, :execute, :after], call_log) - end - - test "around_request? returns false by default" do - config = Configuration.new - refute config.around_request? - end - - test "around_request? returns true when set" do - config = Configuration.new - config.around_request = ->(_data, &request_handler) { request_handler.call } - assert config.around_request? - end - - test "merge preserves around_request from other config" do - custom = ->(_data, &request_handler) { request_handler.call } - config1 = Configuration.new - config2 = Configuration.new(around_request: custom) - merged = config1.merge(config2) - assert_equal custom, merged.around_request - end - - test "merge preserves around_request from self when other not set" do - custom = ->(_data, &request_handler) { request_handler.call } - config1 = Configuration.new(around_request: custom) - config2 = Configuration.new - merged = config1.merge(config2) - assert_equal custom, merged.around_request - end - test "raises ArgumentError when protocol_version is not a supported value" do exception = assert_raises(ArgumentError) do Configuration.new(protocol_version: "1999-12-31") @@ -283,12 +136,5 @@ module MCP end assert_equal("validate_tool_call_arguments must be a boolean", exception.message) end - - test "raises ArgumentError when validate_tool_call_results is not a boolean" do - exception = assert_raises(ArgumentError) do - Configuration.new(validate_tool_call_results: "true") - end - assert_equal("validate_tool_call_results must be a boolean", exception.message) - end end end diff --git a/test/mcp/content_test.rb b/test/mcp/content_test.rb deleted file mode 100644 index fc2103e..0000000 --- a/test/mcp/content_test.rb +++ /dev/null @@ -1,169 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - module Content - class ImageTest < ActiveSupport::TestCase - test "#to_h returns mimeType (camelCase) per MCP spec" do - image = Image.new("base64data", "image/png") - result = image.to_h - - assert_equal "image/png", result[:mimeType] - refute result.key?(:mime_type), "Expected camelCase mimeType, got snake_case mime_type" - assert_equal "image", result[:type] - assert_equal "base64data", result[:data] - end - - test "#to_h with annotations" do - image = Image.new("base64data", "image/png", annotations: { role: "thumbnail" }) - result = image.to_h - - assert_equal({ role: "thumbnail" }, result[:annotations]) - end - - test "#to_h without annotations omits the key" do - image = Image.new("base64data", "image/png") - result = image.to_h - - refute result.key?(:annotations) - end - - test "#to_h with meta" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - image = Image.new("base64data", "image/png", meta: meta) - - assert_equal meta, image.to_h[:_meta] - end - - test "#to_h without meta omits the key" do - image = Image.new("base64data", "image/png") - - refute image.to_h.key?(:_meta) - end - end - - class AudioTest < ActiveSupport::TestCase - test "#to_h returns correct format per MCP spec" do - audio = Audio.new("base64data", "audio/wav") - result = audio.to_h - - assert_equal "audio", result[:type] - assert_equal "base64data", result[:data] - assert_equal "audio/wav", result[:mimeType] - end - - test "#to_h with annotations" do - audio = Audio.new("base64data", "audio/wav", annotations: { role: "recording" }) - result = audio.to_h - - assert_equal({ role: "recording" }, result[:annotations]) - end - - test "#to_h without annotations omits the key" do - audio = Audio.new("base64data", "audio/wav") - result = audio.to_h - - refute result.key?(:annotations) - end - - test "#to_h with meta" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - audio = Audio.new("base64data", "audio/wav", meta: meta) - - assert_equal meta, audio.to_h[:_meta] - end - - test "#to_h without meta omits the key" do - audio = Audio.new("base64data", "audio/wav") - - refute audio.to_h.key?(:_meta) - end - end - - class EmbeddedResourceTest < ActiveSupport::TestCase - test "#to_h returns correct format per MCP spec" do - resource = Object.new - def resource.to_h - { uri: "test://example", mimeType: "text/plain", text: "content" } - end - - embedded = EmbeddedResource.new(resource) - result = embedded.to_h - - assert_equal "resource", result[:type] - assert_equal({ uri: "test://example", mimeType: "text/plain", text: "content" }, result[:resource]) - end - - test "#to_h with annotations" do - resource = Object.new - def resource.to_h - { uri: "test://x" } - end - - embedded = EmbeddedResource.new(resource, annotations: { role: "data" }) - result = embedded.to_h - - assert_equal({ role: "data" }, result[:annotations]) - end - - test "#to_h without annotations omits the key" do - resource = Object.new - def resource.to_h - { uri: "test://x" } - end - - embedded = EmbeddedResource.new(resource) - result = embedded.to_h - - refute result.key?(:annotations) - end - - test "#to_h with meta" do - resource = Object.new - def resource.to_h - { uri: "test://x" } - end - - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - embedded = EmbeddedResource.new(resource, meta: meta) - - assert_equal meta, embedded.to_h[:_meta] - end - - test "#to_h without meta omits the key" do - resource = Object.new - def resource.to_h - { uri: "test://x" } - end - - embedded = EmbeddedResource.new(resource) - - refute embedded.to_h.key?(:_meta) - end - end - - class TextTest < ActiveSupport::TestCase - test "#to_h returns correct format per MCP spec" do - text = Text.new("hello") - result = text.to_h - - assert_equal "text", result[:type] - assert_equal "hello", result[:text] - end - - test "#to_h with meta" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - text = Text.new("hello", meta: meta) - - assert_equal meta, text.to_h[:_meta] - end - - test "#to_h without meta omits the key" do - text = Text.new("hello") - - refute text.to_h.key?(:_meta) - end - end - end -end diff --git a/test/mcp/elicitation/enum_schema_test.rb b/test/mcp/elicitation/enum_schema_test.rb deleted file mode 100644 index 19a4246..0000000 --- a/test/mcp/elicitation/enum_schema_test.rb +++ /dev/null @@ -1,143 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - module Elicitation - class EnumSchemaTest < ActiveSupport::TestCase - test "untitled_single_select returns string + enum schema" do - schema = EnumSchema.untitled_single_select(values: ["red", "green", "blue"]) - - assert_equal({ type: "string", enum: ["red", "green", "blue"] }, schema.to_h) - end - - test "untitled_single_select preserves default value" do - schema = EnumSchema.untitled_single_select(values: ["red", "green"], default: "red") - - assert_equal "red", schema.to_h[:default] - end - - test "titled_single_select returns string + oneOf schema" do - schema = EnumSchema.titled_single_select( - options: [ - { value: "small", title: "Small" }, - { value: "large", title: "Large" }, - ], - ) - - assert_equal( - { - type: "string", - oneOf: [ - { const: "small", title: "Small" }, - { const: "large", title: "Large" }, - ], - }, - schema.to_h, - ) - end - - test "untitled_multi_select returns array + items.enum schema" do - schema = EnumSchema.untitled_multi_select(values: ["a", "b", "c"]) - - assert_equal( - { type: "array", items: { type: "string", enum: ["a", "b", "c"] } }, - schema.to_h, - ) - end - - test "untitled_multi_select preserves default array" do - schema = EnumSchema.untitled_multi_select(values: ["a", "b"], default: ["a"]) - - assert_equal ["a"], schema.to_h[:default] - end - - test "titled_multi_select returns array + items.anyOf schema" do - schema = EnumSchema.titled_multi_select( - options: [ - { value: "us", title: "United States" }, - { value: "jp", title: "Japan" }, - ], - ) - - assert_equal( - { - type: "array", - items: { - anyOf: [ - { const: "us", title: "United States" }, - { const: "jp", title: "Japan" }, - ], - }, - }, - schema.to_h, - ) - end - - test "legacy_titled returns enum + enumNames" do - schema = EnumSchema.legacy_titled( - values: ["s", "m", "l"], - value_titles: ["Small", "Medium", "Large"], - ) - - assert_equal( - { - type: "string", - enum: ["s", "m", "l"], - enumNames: ["Small", "Medium", "Large"], - }, - schema.to_h, - ) - end - - test "title and description are included when provided" do - schema = EnumSchema.untitled_single_select( - values: ["a"], - title: "Color", - description: "Pick a color", - ) - - assert_equal "Color", schema.to_h[:title] - assert_equal "Pick a color", schema.to_h[:description] - end - - test "raises ArgumentError when values array is empty" do - assert_raises(ArgumentError) do - EnumSchema.untitled_single_select(values: []) - end - end - - test "raises ArgumentError when titled options miss :value" do - assert_raises(ArgumentError) do - EnumSchema.titled_single_select(options: [{ title: "missing value" }]) - end - end - - test "raises ArgumentError when titled options miss :title" do - assert_raises(ArgumentError) do - EnumSchema.titled_single_select(options: [{ value: "v" }]) - end - end - - test "raises ArgumentError when legacy value_titles length differs" do - assert_raises(ArgumentError) do - EnumSchema.legacy_titled(values: ["a", "b"], value_titles: ["A"]) - end - end - - test "preserves an empty-string default value" do - # Regression for `unless @default.nil?`: empty-but-non-nil defaults must still survive `to_h` - # (the guard distinguishes nil from "absent vs supplied", not truthy vs falsey). - schema = EnumSchema.untitled_single_select(values: ["", "yes", "no"], default: "") - - assert_equal "", schema.to_h[:default] - end - - test "preserves an empty-array default for multi-select" do - schema = EnumSchema.untitled_multi_select(values: ["a", "b"], default: []) - - assert_equal [], schema.to_h[:default] - end - end - end -end diff --git a/test/mcp/error_codes_test.rb b/test/mcp/error_codes_test.rb deleted file mode 100644 index 80826b8..0000000 --- a/test/mcp/error_codes_test.rb +++ /dev/null @@ -1,14 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ErrorCodesTest < ActiveSupport::TestCase - test "exposes the SEP-2575 stateless lifecycle error codes" do - # The exact values are wire vocabulary shared with other SDKs. - assert_equal(-32020, ErrorCodes::HEADER_MISMATCH) - assert_equal(-32021, ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY) - assert_equal(-32022, ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION) - end - end -end diff --git a/test/mcp/icon_test.rb b/test/mcp/icon_test.rb index f2fbc9a..a4ac119 100644 --- a/test/mcp/icon_test.rb +++ b/test/mcp/icon_test.rb @@ -15,112 +15,32 @@ module MCP assert_equal({ mimeType: "image/png", sizes: ["48x48", "96x96"], src: "https://example.com", theme: "light" }, icon.to_h) end - def test_initialization_with_only_src - icon = Icon.new(src: "https://example.com/icon.png") + def test_initialization_by_default + icon = Icon.new assert_nil(icon.mime_type) assert_nil(icon.sizes) - assert_equal("https://example.com/icon.png", icon.src) + assert_nil(icon.src) assert_nil(icon.theme) - assert_equal({ src: "https://example.com/icon.png" }, icon.to_h) - end - - def test_src_is_required - exception = assert_raises(ArgumentError) do - Icon.new - end - assert_equal("missing keyword: :src", exception.message) - end - - def test_src_rejects_nil_and_an_empty_string - [nil, ""].each do |src| - exception = assert_raises(ArgumentError) do - Icon.new(src: src) - end - assert_equal("The value of src must be a non-empty String (got #{src.class}).", exception.message) - end - end - - def test_src_rejects_a_non_string - exception = assert_raises(ArgumentError) do - Icon.new(src: :icon) - end - assert_equal("The value of src must be a non-empty String (got Symbol).", exception.message) - end - - def test_sizes_accepts_an_array_of_strings - [["48x48", "96x96"], ["any"], []].each do |sizes| - icon = Icon.new(sizes: sizes, src: "https://example.com/icon.png") - - assert_equal(sizes, icon.to_h[:sizes]) - end - end - - # https://github.com/modelcontextprotocol/ruby-sdk/issues/562 - def test_sizes_rejects_a_string - exception = assert_raises(ArgumentError) do - Icon.new(mime_type: "image/png", sizes: "51x51", src: "https://example.com/icon.png") - end - assert_equal( - 'The value of sizes must be an Array of Strings such as ["48x48"] or ["any"] (got String).', - exception.message, - ) - end - - def test_sizes_rejects_an_array_holding_a_non_string - { - ["48x48", 96] => "Integer", - [nil] => "NilClass", - ["48x48", nil] => "NilClass", - [nil, 96] => "NilClass", - }.each do |sizes, offender| - exception = assert_raises(ArgumentError) do - Icon.new(sizes: sizes, src: "https://example.com/icon.png") - end - assert_equal( - "The value of sizes must be an Array of Strings such as [\"48x48\"] or [\"any\"] (got #{offender} inside the Array).", - exception.message, - ) - end - end - - def test_src_accepts_any_scheme_and_sizes_accept_any_string - string_subclass = Class.new(String) - icon = Icon.new(sizes: ["unconventional", +"48x48", string_subclass.new("any")], src: "custom:icon") - - assert_equal({ sizes: ["unconventional", "48x48", "any"], src: "custom:icon" }, icon.to_h) - end - - def test_mime_type_rejects_a_non_string - exception = assert_raises(ArgumentError) do - Icon.new(mime_type: :png, src: "https://example.com/icon.png") - end - assert_equal("The value of mime_type must be a String (got Symbol).", exception.message) + assert_empty(icon.to_h) end def test_valid_theme_for_light assert_nothing_raised do - Icon.new(src: "https://example.com/icon.png", theme: "light") + Icon.new(theme: "light") end end def test_valid_theme_for_dark assert_nothing_raised do - Icon.new(src: "https://example.com/icon.png", theme: "dark") + Icon.new(theme: "dark") end end def test_invalid_theme exception = assert_raises(ArgumentError) do - Icon.new(src: "https://example.com/icon.png", theme: "unexpected") - end - assert_equal('The value of theme must specify "light" or "dark".', exception.message) - end - - def test_theme_rejects_false - exception = assert_raises(ArgumentError) do - Icon.new(src: "https://example.com/icon.png", theme: false) + Icon.new(theme: "unexpected") end assert_equal('The value of theme must specify "light" or "dark".', exception.message) end diff --git a/test/mcp/instrumentation_test.rb b/test/mcp/instrumentation_test.rb index 8fb06af..e1ecf51 100644 --- a/test/mcp/instrumentation_test.rb +++ b/test/mcp/instrumentation_test.rb @@ -1,7 +1,6 @@ # frozen_string_literal: true require "test_helper" -require "mcp/instrumentation" module MCP class InstrumentationTest < ActiveSupport::TestCase @@ -25,92 +24,6 @@ module MCP add_instrumentation_data(additional_data: "test") end end - - def instrumented_method_with_server_context(context) - instrument_call("instrumented_method_with_server_context", server_context: context) do - # nothing to do - end - end - - def instrumented_method_that_raises_with_error_set - instrument_call("instrumented_method_that_raises_with_error_set") do - add_instrumentation_data(error: :custom_error) - raise "block error" - end - end - end - - # Mirrors `MCP::Server`, which exposes the user-defined hash through - # `attr_accessor :server_context`. - class SubjectWithServerContext < Subject - attr_accessor :server_context - - def initialize(server_context) - super() - @server_context = server_context - end - end - - test "#instrument_call omits the user-defined server_context by default" do - subject = SubjectWithServerContext.new({ user_id: 42 }) - - subject.instrumented_method - - refute_includes subject.instrumentation_data_received.keys, :server_context - end - - test "#instrument_call exposes the user-defined server_context when instrument_server_context is enabled" do - subject = SubjectWithServerContext.new({ user_id: 42 }) - subject.configuration.instrument_server_context = true - - subject.instrumented_method - - assert_equal({ user_id: 42 }, subject.instrumentation_data_received[:server_context]) - end - - test "#instrument_call exposes the user-defined server_context to around_request" do - subject = SubjectWithServerContext.new({ user_id: 42 }) - subject.configuration.instrument_server_context = true - seen = nil - subject.configuration.around_request = ->(data, &handler) { - seen = data[:server_context] - handler.call - } - - subject.instrumented_method - - assert_equal({ user_id: 42 }, seen) - end - - test "#instrument_call reports the user-defined server_context as nil when the host does not set one" do - subject = SubjectWithServerContext.new(nil) - subject.configuration.instrument_server_context = true - - subject.instrumented_method - - assert_includes subject.instrumentation_data_received.keys, :server_context - assert_nil subject.instrumentation_data_received[:server_context] - end - - test "#instrument_call does not confuse the reporter context with the user-defined server_context" do - # `instrument_call(server_context:)` is the exception-reporter context, a - # different value from the user-defined hash. Enabling the flag must - # surface the latter, not the former. - subject = SubjectWithServerContext.new({ user_id: 42 }) - subject.configuration.instrument_server_context = true - - subject.instrumented_method_with_server_context({ request: "reporter-context" }) - - assert_equal({ user_id: 42 }, subject.instrumentation_data_received[:server_context]) - end - - test "#instrument_call skips server_context for hosts without the reader even when enabled" do - subject = Subject.new - subject.configuration.instrument_server_context = true - - subject.instrumented_method - - refute_includes subject.instrumentation_data_received.keys, :server_context end test "#instrument_call adds the method name to the instrumentation data" do @@ -132,329 +45,6 @@ module MCP ) end - test "#instrument_call invokes around_request wrapping execution" do - call_log = [] - subject = Subject.new - subject.configuration.around_request = ->(_data, &request_handler) { - call_log << :before - request_handler.call - call_log << :after - } - - subject.instrumented_method - - assert_equal([:before, :after], call_log) - end - - test "#instrument_call around_request receives method before request_handler.call" do - received_method = nil - subject = Subject.new - subject.configuration.around_request = ->(data, &request_handler) { - received_method = data[:method] - request_handler.call - } - - subject.instrumented_method - - assert_equal("instrumented_method", received_method) - end - - test "#instrument_call around_request data is populated after request_handler.call" do - data_after_call = nil - subject = Subject.new - subject.configuration.around_request = ->(data, &request_handler) { - request_handler.call - data_after_call = data.dup - } - - subject.instrumented_method_with_additional_data - - assert_equal("instrumented_method_with_additional_data", data_after_call[:method]) - assert_equal("test", data_after_call[:additional_data]) - end - - test "#instrument_call default around_request is pass-through" do - subject = Subject.new - - subject.instrumented_method_with_additional_data - - assert_equal( - { method: "instrumented_method_with_additional_data", additional_data: "test" }, - subject.instrumentation_data_received.tap { |data| data.delete(:duration) }, - ) - end - - test "#instrument_call reports exception and sets error when around_request raises before request_handler.call" do - reported_exception = nil - reported_context = nil - subject = Subject.new - subject.configuration.exception_reporter = ->(e, server_context) { - reported_exception = e - reported_context = server_context - } - subject.configuration.around_request = ->(_data, &_request_handler) { raise "boom before" } - - error = assert_raises(RuntimeError) { subject.instrumented_method } - assert_equal("boom before", error.message) - assert_same(error, reported_exception) - assert_equal({}, reported_context) - assert_equal(:internal_error, subject.instrumentation_data_received[:error]) - assert(subject.instrumentation_data_received.key?(:duration)) - end - - test "#instrument_call reports exception and sets error when around_request raises after request_handler.call" do - reported_exception = nil - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported_exception = e } - subject.configuration.around_request = ->(_data, &request_handler) { - request_handler.call - raise "boom after" - } - - error = assert_raises(RuntimeError) { subject.instrumented_method } - assert_equal("boom after", error.message) - assert_same(error, reported_exception) - assert_equal(:internal_error, subject.instrumentation_data_received[:error]) - end - - test "#instrument_call preserves block's custom error tag and reports the exception" do - report_count = 0 - subject = Subject.new - subject.configuration.exception_reporter = ->(_e, _server_context) { report_count += 1 } - - assert_raises(RuntimeError) { subject.instrumented_method_that_raises_with_error_set } - assert_equal(1, report_count) - assert_equal(:custom_error, subject.instrumentation_data_received[:error]) - end - - test "#instrument_call skips reporting when exception_already_reported returns true" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - error = StandardError.new("inner failure") - subject.define_singleton_method(:instrumented_with_skip) do - instrument_call("instrumented_with_skip", exception_already_reported: ->(e) { error.equal?(e) }) do - raise error - end - end - - assert_raises(StandardError) { subject.instrumented_with_skip } - assert_equal([], reported) - end - - test "#instrument_call reports when exception_already_reported returns false for a new exception" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - target = StandardError.new("inner failure") - subject.configuration.around_request = ->(_data, &request_handler) do - request_handler.call - ensure - raise "ensure boom" - end - - subject.define_singleton_method(:instrumented_with_skip) do - instrument_call("instrumented_with_skip", exception_already_reported: ->(e) { target.equal?(e) }) do - raise target - end - end - - assert_raises(RuntimeError) { subject.instrumented_with_skip } - assert_equal(["ensure boom"], reported) - end - - test "#instrument_call falls back to reporting when exception_already_reported itself raises" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - subject.define_singleton_method(:instrumented_with_broken_predicate) do - instrument_call( - "instrumented_with_broken_predicate", - exception_already_reported: ->(_e) { raise "predicate blew up" }, - ) do - raise "original failure" - end - end - - error = assert_raises(RuntimeError) { subject.instrumented_with_broken_predicate } - assert_equal("original failure", error.message) - assert_equal(["original failure"], reported) - end - - test "#instrument_call falls back to reporting when exception_already_reported raises a non-StandardError" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - subject.define_singleton_method(:instrumented_with_system_exit_predicate) do - instrument_call( - "instrumented_with_system_exit_predicate", - exception_already_reported: ->(_e) { raise SystemExit, 9 }, - ) do - raise "original failure" - end - end - - error = assert_raises(RuntimeError) { subject.instrumented_with_system_exit_predicate } - assert_equal("original failure", error.message) - assert_equal(["original failure"], reported) - end - - test "#instrument_call normalizes non-boolean truthy return values from exception_already_reported" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - subject.define_singleton_method(:instrumented_with_truthy_predicate) do - instrument_call( - "instrumented_with_truthy_predicate", - exception_already_reported: ->(_e) { "non-boolean truthy" }, - ) do - raise "original failure" - end - end - - assert_raises(RuntimeError) { subject.instrumented_with_truthy_predicate } - assert_equal([], reported) - end - - test "#instrument_call reports when exception_already_reported returns nil" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - subject.define_singleton_method(:instrumented_with_nil_predicate) do - instrument_call( - "instrumented_with_nil_predicate", - exception_already_reported: ->(_e) { nil }, - ) do - raise "original failure" - end - end - - assert_raises(RuntimeError) { subject.instrumented_with_nil_predicate } - assert_equal(["original failure"], reported) - end - - test "#instrument_call does not carry reported state across invocations when the same exception is reused" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - shared_error = RuntimeError.new("reused") - subject.configuration.around_request = ->(_data, &_request_handler) { raise shared_error } - - 2.times do - assert_raises(RuntimeError) { subject.instrumented_method } - end - assert_equal(["reused", "reused"], reported) - end - - test "#instrument_call reports frozen exceptions without mutating them" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e } - - frozen_error = RuntimeError.new("frozen").freeze - subject.configuration.around_request = ->(_data, &_request_handler) { raise frozen_error } - - error = assert_raises(RuntimeError) { subject.instrumented_method } - assert_same(frozen_error, error) - assert_equal([frozen_error], reported) - assert_predicate(frozen_error, :frozen?) - end - - test "#instrument_call nested calls sharing an exception_already_reported predicate report only once" do - reported = [] - subject = Subject.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - reported_exception = nil - predicate = ->(e) { reported_exception.equal?(e) } - - subject.define_singleton_method(:outer) do - instrument_call("outer", exception_already_reported: predicate) { inner } - end - - subject.define_singleton_method(:inner) do - instrument_call("inner", exception_already_reported: predicate) do - raise "nested boom" - rescue => e - configuration.exception_reporter.call(e, {}) - reported_exception = e - raise - end - end - - assert_raises(RuntimeError) { subject.outer } - assert_equal(["nested boom"], reported) - end - - test "#instrument_call keeps reported state isolated across concurrent threads on a shared subject" do - subject = Subject.new - reported = Queue.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - threads = 10.times.map do |i| - Thread.new do - subject.instrument_call("threaded_#{i}") { raise "thread #{i}" } - rescue RuntimeError - # Swallow the intentional raise so the thread finishes cleanly. - # The test verifies side effects via the shared `reported` queue. - end - end - threads.each(&:join) - - messages = [] - messages << reported.pop until reported.empty? - - assert_equal(10.times.map { |i| "thread #{i}" }, messages.sort) - end - - test "#instrument_call reports each invocation when the same exception instance is raised from multiple threads" do - subject = Subject.new - reported = Queue.new - subject.configuration.exception_reporter = ->(e, _server_context) { reported << e } - - shared_error = RuntimeError.new("shared across threads") - start_gate = Queue.new - - threads = 10.times.map do - Thread.new do - start_gate.pop - begin - subject.instrument_call("shared_error_method") { raise shared_error } - rescue RuntimeError - # Swallow the intentional raise so the thread finishes cleanly. - # The test verifies side effects via the shared `reported` queue. - end - end - end - 10.times { start_gate << :go } - threads.each(&:join) - - collected = [] - collected << reported.pop until reported.empty? - - assert_equal(10, collected.size) - assert(collected.all? { |e| e.equal?(shared_error) }) - end - - test "#instrument_call forwards server_context to exception_reporter on around_request failure" do - reported_context = nil - subject = Subject.new - subject.configuration.exception_reporter = ->(_e, server_context) { reported_context = server_context } - subject.configuration.around_request = ->(_data, &_request_handler) { raise "boom" } - - assert_raises(RuntimeError) do - subject.instrumented_method_with_server_context(request: { id: 42 }) - end - assert_equal({ request: { id: 42 } }, reported_context) - end - test "#instrument_call resets the instrumentation data between calls" do subject = Subject.new diff --git a/test/mcp/logging_message_notification_test.rb b/test/mcp/logging_message_notification_test.rb deleted file mode 100644 index 7eb7515..0000000 --- a/test/mcp/logging_message_notification_test.rb +++ /dev/null @@ -1,47 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class LoggingMessageNotificationTest < ActiveSupport::TestCase - test "valid_level? returns true for valid levels" do - LoggingMessageNotification::LOG_LEVEL_SEVERITY.keys.each do |level| - logging_message_notification = LoggingMessageNotification.new(level: level) - assert logging_message_notification.valid_level?, "#{level} should be valid" - end - end - - test "valid_level? returns false for invalid levels" do - invalid_levels = ["invalid", 1, "", nil, :fatal] - invalid_levels.each do |level| - logging_message_notification = LoggingMessageNotification.new(level: level) - refute logging_message_notification.valid_level?, "#{level} should be invalid" - end - end - - test "should_notify? returns true when notification level is higher priority than threshold level or equals to it" do - logging_message_notification = LoggingMessageNotification.new(level: "warning") - assert logging_message_notification.should_notify?("warning") - assert logging_message_notification.should_notify?("error") - assert logging_message_notification.should_notify?("critical") - assert logging_message_notification.should_notify?("alert") - assert logging_message_notification.should_notify?("emergency") - end - - test "should_notify? returns false when notification level is lower priority than threshold level" do - logging_message_notification = LoggingMessageNotification.new(level: "warning") - refute logging_message_notification.should_notify?("notice") - refute logging_message_notification.should_notify?("info") - refute logging_message_notification.should_notify?("debug") - end - - test "should_notify? returns false for invalid log levels" do - logging_message_notification = LoggingMessageNotification.new(level: "warning") - refute logging_message_notification.should_notify?("invalid") - refute logging_message_notification.should_notify?(1) - refute logging_message_notification.should_notify?("") - refute logging_message_notification.should_notify?(nil) - refute logging_message_notification.should_notify?(:fatal) - end - end -end diff --git a/test/mcp/methods_test.rb b/test/mcp/methods_test.rb index c6ae11a..0f765d9 100644 --- a/test/mcp/methods_test.rb +++ b/test/mcp/methods_test.rb @@ -1,7 +1,6 @@ # frozen_string_literal: true require "test_helper" -require "mcp/methods" module MCP class MethodsTest < ActiveSupport::TestCase @@ -24,8 +23,6 @@ module MCP # Server methods and notifications ensure_capability_does_not_raise_for Methods::INITIALIZE - # `server/discover` (SEP-2575) must respond regardless of declared capabilities. - ensure_capability_does_not_raise_for Methods::SERVER_DISCOVER ensure_capability_raises_error_for Methods::PROMPTS_LIST, required_capability_name: "prompts" ensure_capability_raises_error_for Methods::PROMPTS_GET, required_capability_name: "prompts" @@ -70,7 +67,10 @@ module MCP ensure_capability_does_not_raise_for Methods::NOTIFICATIONS_INITIALIZED ensure_capability_raises_error_for Methods::ROOTS_LIST, required_capability_name: "roots" - ensure_capability_does_not_raise_for Methods::NOTIFICATIONS_ROOTS_LIST_CHANGED + ensure_capability_raises_error_for Methods::NOTIFICATIONS_ROOTS_LIST_CHANGED, required_capability_name: "roots" + ensure_capability_raises_error_for Methods::NOTIFICATIONS_ROOTS_LIST_CHANGED, + required_capability_name: "roots.listChanged", + capabilities: { roots: {} } ensure_capability_raises_error_for Methods::SAMPLING_CREATE_MESSAGE, required_capability_name: "sampling" @@ -80,6 +80,5 @@ module MCP ensure_capability_does_not_raise_for Methods::PING ensure_capability_does_not_raise_for Methods::NOTIFICATIONS_PROGRESS ensure_capability_does_not_raise_for Methods::NOTIFICATIONS_CANCELLED - ensure_capability_does_not_raise_for Methods::NOTIFICATIONS_ELICITATION_COMPLETE end end diff --git a/test/mcp/progress_test.rb b/test/mcp/progress_test.rb deleted file mode 100644 index e9552ba..0000000 --- a/test/mcp/progress_test.rb +++ /dev/null @@ -1,71 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ProgressTest < ActiveSupport::TestCase - class MockTransport < Transport - attr_reader :notifications - - def initialize(server) - super - @notifications = [] - end - - def send_notification(method, params = nil) - @notifications << { method: method, params: params } - true - end - - def send_response(response); end - def open; end - def close; end - def handle_request(request); end - end - - setup do - @server = Server.new(name: "test_server") - @transport = MockTransport.new(@server) - @session = ServerSession.new(server: @server, transport: @transport) - end - - test "#report is a no-op when progress_token is nil" do - progress = Progress.new(notification_target: @session, progress_token: nil) - progress.report(50, total: 100, message: "halfway") - - assert_equal 0, @transport.notifications.size - end - - test "#report is a no-op when notification_target is nil" do - progress = Progress.new(notification_target: nil, progress_token: "token-1") - progress.report(50, total: 100, message: "halfway") - - assert_equal 0, @transport.notifications.size - end - - test "#report sends notification when progress_token is present" do - progress = Progress.new(notification_target: @session, progress_token: "token-1") - progress.report(50, total: 100, message: "halfway") - - assert_equal 1, @transport.notifications.size - notification = @transport.notifications.first - assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method] - assert_equal "token-1", notification[:params]["progressToken"] - assert_equal 50, notification[:params]["progress"] - assert_equal 100, notification[:params]["total"] - assert_equal "halfway", notification[:params]["message"] - end - - test "#report omits total and message when not provided" do - progress = Progress.new(notification_target: @session, progress_token: "token-1") - progress.report(50) - - assert_equal 1, @transport.notifications.size - notification = @transport.notifications.first - assert_equal "token-1", notification[:params]["progressToken"] - assert_equal 50, notification[:params]["progress"] - refute notification[:params].key?("total") - refute notification[:params].key?("message") - end - end -end diff --git a/test/mcp/prompt/result_test.rb b/test/mcp/prompt/result_test.rb deleted file mode 100644 index 62f161e..0000000 --- a/test/mcp/prompt/result_test.rb +++ /dev/null @@ -1,41 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Prompt - class ResultTest < ActiveSupport::TestCase - test "#to_h returns description and messages" do - result = Prompt::Result.new( - description: "a prompt", - messages: [Prompt::Message.new(role: "user", content: Content::Text.new("hi"))], - ) - - hash = result.to_h - - assert_equal "a prompt", hash[:description] - assert_equal 1, hash[:messages].size - end - - test "#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - result = Prompt::Result.new( - description: "a prompt", - messages: [Prompt::Message.new(role: "user", content: Content::Text.new("hi"))], - meta: meta, - ) - - assert_equal meta, result.to_h[:_meta] - end - - test "#to_h omits _meta when nil" do - result = Prompt::Result.new( - description: "a prompt", - messages: [Prompt::Message.new(role: "user", content: Content::Text.new("hi"))], - ) - - refute result.to_h.key?(:_meta) - end - end - end -end diff --git a/test/mcp/prompt_test.rb b/test/mcp/prompt_test.rb index a6fe18a..a434e06 100644 --- a/test/mcp/prompt_test.rb +++ b/test/mcp/prompt_test.rb @@ -182,7 +182,7 @@ module MCP assert_equal expected, FullPrompt.to_h end - test "#to_h omits arguments key when arguments are not declared" do + test "#to_h handles nil arguments value" do class NoArgumentsPrompt < Prompt description "No arguments prompt" end @@ -196,51 +196,6 @@ module MCP assert_equal expected, prompt.to_h end - test "#validate_arguments! does not raise when arguments are not declared" do - prompt_class = Class.new(Prompt) do - prompt_name "no_args_prompt" - description "A prompt with no arguments" - # NOTE: no `arguments` declaration at all - end - - assert_nothing_raised do - prompt_class.validate_arguments!({}) - end - end - - test "#validate_arguments! handles nil args" do - prompt_class = Class.new(Prompt) do - prompt_name "no_args_prompt" - description "A prompt with no arguments" - end - - assert_nothing_raised do - prompt_class.validate_arguments!(nil) - end - end - - test "#validate_arguments! does not raise when arguments is explicitly set to nil" do - prompt_class = Class.new(Prompt) do - prompt_name "nil_args_prompt" - description "A prompt with nil arguments" - arguments nil - end - - assert_nothing_raised do - prompt_class.validate_arguments!({}) - end - end - - test "#to_h omits arguments key when arguments is empty" do - prompt = Prompt.define( - name: "no_args_prompt", - description: "a prompt without arguments", - arguments: [], - ) - - refute prompt.to_h.key?(:arguments) - end - test "#to_h does not have `:icons` key when icons is empty" do prompt = Prompt.define( name: "prompt_without_icons", diff --git a/test/mcp/protocol_deprecations_test.rb b/test/mcp/protocol_deprecations_test.rb deleted file mode 100644 index d7fbbd9..0000000 --- a/test/mcp/protocol_deprecations_test.rb +++ /dev/null @@ -1,14 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ProtocolDeprecationsTest < ActiveSupport::TestCase - test "roots, sampling, and logging are deprecated in 2026-07-28 and later" do - refute ProtocolDeprecations.deprecated_roots_sampling_logging?(nil) - refute ProtocolDeprecations.deprecated_roots_sampling_logging?("2025-11-25") - assert ProtocolDeprecations.deprecated_roots_sampling_logging?("2026-07-28") - assert ProtocolDeprecations.deprecated_roots_sampling_logging?("2027-01-01") - end - end -end diff --git a/test/mcp/request_envelope_test.rb b/test/mcp/request_envelope_test.rb deleted file mode 100644 index e7261be..0000000 --- a/test/mcp/request_envelope_test.rb +++ /dev/null @@ -1,145 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class RequestEnvelopeTest < ActiveSupport::TestCase - test "exposes the reserved SEP-2575 meta key names" do - # The exact strings are wire vocabulary shared with other SDKs. - assert_equal "io.modelcontextprotocol/protocolVersion", RequestEnvelope::PROTOCOL_VERSION_META_KEY - assert_equal "io.modelcontextprotocol/clientInfo", RequestEnvelope::CLIENT_INFO_META_KEY - assert_equal "io.modelcontextprotocol/clientCapabilities", RequestEnvelope::CLIENT_CAPABILITIES_META_KEY - assert_equal "io.modelcontextprotocol/logLevel", RequestEnvelope::LOG_LEVEL_META_KEY - end - - test ".modern? returns true when the protocolVersion claim key is present" do - assert RequestEnvelope.modern?(modern_params) - assert RequestEnvelope.modern?({ _meta: { "io.modelcontextprotocol/protocolVersion": "2026-07-28" } }) - end - - test ".modern? returns true for string keys" do - params = { - "_meta" => { - "io.modelcontextprotocol/protocolVersion" => "2026-07-28", - "io.modelcontextprotocol/clientInfo" => { "name" => "c", "version" => "1" }, - "io.modelcontextprotocol/clientCapabilities" => {}, - }, - } - - assert RequestEnvelope.modern?(params) - end - - test ".modern? stays true for a claimed but incomplete envelope" do - # A claimed envelope must be validated by `parse!` (`-32602`), never silently served as legacy, - # matching the TypeScript and Python classifiers. - params = modern_params - params[:_meta].delete(:"io.modelcontextprotocol/clientCapabilities") - - assert RequestEnvelope.modern?(params) - end - - test ".modern? returns false for legacy _meta entries such as progressToken" do - refute RequestEnvelope.modern?({ name: "echo", _meta: { progressToken: "token" } }) - end - - test ".modern? returns false without params or _meta" do - refute RequestEnvelope.modern?(nil) - refute RequestEnvelope.modern?({}) - refute RequestEnvelope.modern?({ name: "echo" }) - refute RequestEnvelope.modern?({ _meta: nil }) - end - - test ".parse! returns a frozen envelope with the triple and optional log level" do - params = modern_params - params[:_meta][:"io.modelcontextprotocol/logLevel"] = "warning" - - envelope = RequestEnvelope.parse!(params) - - assert_predicate envelope, :frozen? - assert_equal "2026-07-28", envelope.protocol_version - assert_equal({ name: "test_client", version: "1.0.0" }, envelope.client_info) - assert_equal({ elicitation: {} }, envelope.client_capabilities) - assert_equal "warning", envelope.log_level - end - - test ".parse! leaves log_level nil when absent" do - assert_nil RequestEnvelope.parse!(modern_params).log_level - end - - test ".parse! raises UnsupportedProtocolVersionError with the SEP-2575 data shape" do - params = modern_params(version: "2025-11-25") - - error = assert_raises(Server::UnsupportedProtocolVersionError) do - RequestEnvelope.parse!(params) - end - - assert_equal ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, error.error_code - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, error.error_data[:supported] - assert_equal "2025-11-25", error.error_data[:requested] - end - - test ".parse! accepts an envelope without the optional clientInfo" do - # `clientInfo` became optional after the SEP was finalized (spec PR #3002); - # a conformant client configured not to identify itself must not be rejected. - params = modern_params - params[:_meta].delete(:"io.modelcontextprotocol/clientInfo") - - envelope = RequestEnvelope.parse!(params) - - assert_nil envelope.client_info - assert_equal "2026-07-28", envelope.protocol_version - assert_equal({ elicitation: {} }, envelope.client_capabilities) - end - - test ".parse! raises Invalid params naming the missing key when clientCapabilities is absent" do - params = modern_params - params[:_meta].delete(:"io.modelcontextprotocol/clientCapabilities") - - error = assert_raises(Server::RequestHandlerError) do - RequestEnvelope.parse!(params) - end - - assert_equal :invalid_params, error.error_type - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, error.error_code - assert_includes error.message, "io.modelcontextprotocol/clientCapabilities" - refute_includes error.message, "io.modelcontextprotocol/protocolVersion" - end - - test ".parse! raises Invalid params when a required field has the wrong type" do - params = modern_params - params[:_meta][:"io.modelcontextprotocol/clientCapabilities"] = "not-a-hash" - - error = assert_raises(Server::RequestHandlerError) do - RequestEnvelope.parse!(params) - end - - assert_equal :invalid_params, error.error_type - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, error.error_code - end - - test ".parse! raises Invalid params when the optional clientInfo has the wrong type" do - params = modern_params - params[:_meta][:"io.modelcontextprotocol/clientInfo"] = "not-a-hash" - - error = assert_raises(Server::RequestHandlerError) do - RequestEnvelope.parse!(params) - end - - assert_equal :invalid_params, error.error_type - assert_includes error.message, "io.modelcontextprotocol/clientInfo" - end - - private - - def modern_params(version: "2026-07-28") - { - name: "echo", - _meta: { - "io.modelcontextprotocol/protocolVersion": version, - "io.modelcontextprotocol/clientInfo": { name: "test_client", version: "1.0.0" }, - "io.modelcontextprotocol/clientCapabilities": { elicitation: {} }, - }, - } - end - end -end diff --git a/test/mcp/resource/contents_test.rb b/test/mcp/resource/contents_test.rb deleted file mode 100644 index f89f8f2..0000000 --- a/test/mcp/resource/contents_test.rb +++ /dev/null @@ -1,147 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Resource - class ContentsTest < ActiveSupport::TestCase - test "Contents#to_h returns hash with mimeType" do - contents = Resource::Contents.new( - uri: "test://example", - mime_type: "text/plain", - ) - - result = contents.to_h - - assert_equal "test://example", result[:uri] - assert_equal "text/plain", result[:mimeType] - refute result.key?(:mime_type), "Should use camelCase 'mimeType' not snake_case 'mime_type'" - end - - test "Contents#to_h omits mimeType when nil" do - contents = Resource::Contents.new(uri: "test://example") - - result = contents.to_h - - assert_equal({ uri: "test://example" }, result) - refute result.key?(:mimeType) - end - - test "TextContents#to_h returns hash with text and mimeType" do - text_contents = Resource::TextContents.new( - uri: "test://text", - mime_type: "text/plain", - text: "Hello, world!", - ) - - result = text_contents.to_h - - assert_equal "test://text", result[:uri] - assert_equal "text/plain", result[:mimeType] - assert_equal "Hello, world!", result[:text] - refute result.key?(:mime_type), "Should use camelCase 'mimeType' not snake_case 'mime_type'" - end - - test "BlobContents#to_h returns hash with blob and mimeType" do - blob_contents = Resource::BlobContents.new( - uri: "test://binary", - mime_type: "image/png", - data: "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==", - ) - - result = blob_contents.to_h - - assert_equal "test://binary", result[:uri] - assert_equal "image/png", result[:mimeType] - assert_equal "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==", result[:blob] - refute result.key?(:data), "Should use 'blob' not 'data' per MCP specification" - refute result.key?(:mime_type), "Should use camelCase 'mimeType' not snake_case 'mime_type'" - end - - test "BlobContents#to_h omits mimeType when nil" do - blob_contents = Resource::BlobContents.new( - uri: "test://binary", - mime_type: nil, - data: "base64data", - ) - - result = blob_contents.to_h - - assert_equal({ uri: "test://binary", blob: "base64data" }, result) - refute result.key?(:mimeType) - end - - test "Contents#to_h omits _meta when nil" do - contents = Resource::Contents.new(uri: "test://example", mime_type: "text/plain") - - refute contents.to_h.key?(:_meta) - end - - test "Contents#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - contents = Resource::Contents.new(uri: "test://example", mime_type: "text/plain", meta: meta) - - assert_equal meta, contents.to_h[:_meta] - end - - test "TextContents#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - text_contents = Resource::TextContents.new( - uri: "test://text", - mime_type: "text/plain", - text: "Hello", - meta: meta, - ) - - result = text_contents.to_h - - assert_equal meta, result[:_meta] - assert_equal "Hello", result[:text] - end - - test "TextContents#to_h omits _meta when nil" do - text_contents = Resource::TextContents.new( - uri: "test://text", - mime_type: "text/plain", - text: "Hello", - ) - - refute text_contents.to_h.key?(:_meta) - end - - test "BlobContents#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - blob_contents = Resource::BlobContents.new( - uri: "test://binary", - mime_type: "image/png", - data: "base64data", - meta: meta, - ) - - result = blob_contents.to_h - - assert_equal meta, result[:_meta] - assert_equal "base64data", result[:blob] - end - - test "BlobContents#to_h omits _meta when nil" do - blob_contents = Resource::BlobContents.new( - uri: "test://binary", - mime_type: "image/png", - data: "base64data", - ) - - refute blob_contents.to_h.key?(:_meta) - end - - test "Contents#to_h preserves empty _meta hash" do - contents = Resource::Contents.new(uri: "test://example", mime_type: "text/plain", meta: {}) - - result = contents.to_h - - assert result.key?(:_meta) - assert_equal({}, result[:_meta]) - end - end - end -end diff --git a/test/mcp/resource/embedded_test.rb b/test/mcp/resource/embedded_test.rb deleted file mode 100644 index 2967de9..0000000 --- a/test/mcp/resource/embedded_test.rb +++ /dev/null @@ -1,107 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Resource - class EmbeddedTest < ActiveSupport::TestCase - test "initializes with resource" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - ) - embedded = Resource::Embedded.new(resource: resource) - - assert_equal resource, embedded.resource - end - - test "initializes with resource and annotations" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - ) - annotations = { audience: ["user"], priority: 1.0 } - embedded = Resource::Embedded.new(resource: resource, annotations: annotations) - - assert_equal resource, embedded.resource - assert_equal annotations, embedded.annotations - end - - test "initializes with annotations as nil when not provided" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - ) - embedded = Resource::Embedded.new(resource: resource) - - assert_nil embedded.annotations - end - - test "#to_h returns hash with resource data when annotations is nil" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - ) - embedded = Resource::Embedded.new(resource: resource) - - expected = { - resource: { - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - }, - } - - assert_equal expected, embedded.to_h - end - - test "#to_h returns hash with resource and annotations when both are present" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - ) - annotations = { audience: ["user"], priority: 1.0 } - embedded = Resource::Embedded.new(resource: resource, annotations: annotations) - - expected = { - resource: { - uri: "file:///test.txt", - name: "test_resource", - description: "a test resource", - }, - annotations: { audience: ["user"], priority: 1.0 }, - } - - assert_equal expected, embedded.to_h - end - - test "#to_h handles resource with all optional fields" do - resource = Resource.new( - uri: "file:///test.txt", - name: "test_resource", - title: "Test Resource", - description: "a test resource", - mime_type: "text/plain", - ) - embedded = Resource::Embedded.new(resource: resource) - - expected = { - resource: { - uri: "file:///test.txt", - name: "test_resource", - title: "Test Resource", - description: "a test resource", - mimeType: "text/plain", - }, - } - - assert_equal expected, embedded.to_h - end - end - end -end diff --git a/test/mcp/resource_template_test.rb b/test/mcp/resource_template_test.rb index ffe742d..6b8a565 100644 --- a/test/mcp/resource_template_test.rb +++ b/test/mcp/resource_template_test.rb @@ -36,175 +36,5 @@ module MCP assert_equal expected_icons, resource_template.to_h[:icons] end - - test "#to_h omits _meta when nil" do - resource_template = ResourceTemplate.new(uri_template: "file:///{path}", name: "template_without_meta") - - refute resource_template.to_h.key?(:_meta) - end - - test "#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - resource_template = ResourceTemplate.new( - uri_template: "file:///{path}", - name: "template_with_meta", - meta: meta, - ) - - assert_equal meta, resource_template.to_h[:_meta] - end - - test "#to_h omits annotations when nil" do - resource_template = ResourceTemplate.new(uri_template: "file:///{path}", name: "template_without_annotations") - - refute resource_template.to_h.key?(:annotations) - end - - test "#to_h includes annotations when present" do - annotations = Annotations.new(audience: ["user"], priority: 0.8, last_modified: "2025-01-12T15:00:58Z") - resource_template = ResourceTemplate.new( - uri_template: "file:///{path}", - name: "template_with_annotations", - annotations: annotations, - ) - - expected = { audience: ["user"], priority: 0.8, lastModified: "2025-01-12T15:00:58Z" } - assert_equal expected, resource_template.to_h[:annotations] - end - - class UserProfileTemplate < ResourceTemplate - uri_template "users://{user_id}/profile" - title "User Profile" - description "profile for a user" - mime_type "application/json" - - class << self - def contents(user_id:) - [Resource::TextContents.new(uri: "users://#{user_id}/profile", mime_type: mime_type, text: "profile of #{user_id}")] - end - end - end - - test "class-based .to_h emits the same keys as the equivalent instance" do - instance = ResourceTemplate.new( - uri_template: "users://{user_id}/profile", - name: "user_profile_template", - title: "User Profile", - description: "profile for a user", - mime_type: "application/json", - ) - - assert_equal instance.to_h, UserProfileTemplate.to_h - end - - test "class-based name defaults to the snake_cased class name" do - assert_equal "user_profile_template", UserProfileTemplate.name_value - end - - test "explicit resource_template_name wins over the class name" do - template_class = Class.new(UserProfileTemplate) do - resource_template_name "custom_template" - end - - assert_equal "custom_template", template_class.resource_template_name - assert_equal "custom_template", template_class.name_value - end - - test "subclasses of a configured class start clean" do - subclass = Class.new(UserProfileTemplate) - - assert_nil subclass.uri_template - assert_nil subclass.title - assert_nil subclass.description - assert_nil subclass.mime_type - end - - test ".contents raises NotImplementedError unless implemented" do - template_class = Class.new(ResourceTemplate) - - assert_raises(NotImplementedError) { template_class.contents(user_id: "42") } - end - - test ".match_uri extracts a single template variable" do - assert_equal({ user_id: "42" }, UserProfileTemplate.match_uri("users://42/profile")) - end - - test ".match_uri extracts multiple template variables" do - template_class = Class.new(ResourceTemplate) do - uri_template "repos://{owner}/{repo}" - end - - assert_equal({ owner: "octo", repo: "sdk" }, template_class.match_uri("repos://octo/sdk")) - end - - test ".match_uri returns an empty hash for an exact match without variables" do - template_class = Class.new(ResourceTemplate) do - uri_template "config://app" - end - - assert_equal({}, template_class.match_uri("config://app")) - end - - test ".match_uri returns nil when the URI does not match" do - assert_nil UserProfileTemplate.match_uri("users://42/settings") - assert_nil UserProfileTemplate.match_uri("posts://42/profile") - end - - test ".match_uri variables do not cross path separators" do - assert_nil UserProfileTemplate.match_uri("users://42/extra/profile") - end - - test ".match_uri returns nil when uri_template is not set" do - template_class = Class.new(ResourceTemplate) - - assert_nil template_class.match_uri("users://42/profile") - end - - test ".match_uri escapes regex metacharacters in literal parts" do - template_class = Class.new(ResourceTemplate) do - uri_template "file:///data.v1/{name}" - end - - assert_equal({ name: "foo" }, template_class.match_uri("file:///data.v1/foo")) - assert_nil template_class.match_uri("file:///dataXv1/foo") - end - - test ".match_uri treats unsupported RFC 6570 operators as literals" do - template_class = Class.new(ResourceTemplate) do - uri_template "search://items{?query}" - end - - assert_nil template_class.match_uri("search://items?query=foo") - assert_equal({}, template_class.match_uri("search://items{?query}")) - end - - test "re-setting uri_template invalidates the compiled pattern" do - template_class = Class.new(ResourceTemplate) do - uri_template "old://{id}" - end - assert_equal({ id: "1" }, template_class.match_uri("old://1")) - - template_class.uri_template("new://{id}") - - assert_nil template_class.match_uri("old://1") - assert_equal({ id: "2" }, template_class.match_uri("new://2")) - end - - test ".define creates a template class whose block implements contents" do - template_class = ResourceTemplate.define( - uri_template: "items://{item_id}", - name: "item_template", - mime_type: "text/plain", - ) do |item_id:| - [Resource::TextContents.new(uri: "items://#{item_id}", mime_type: mime_type, text: "item #{item_id}")] - end - - assert_equal "items://{item_id}", template_class.uri_template - assert_equal "item_template", template_class.name_value - - contents = template_class.contents(item_id: "7") - assert_equal 1, contents.size - assert_equal "item 7", contents.first.text - end end end diff --git a/test/mcp/resource_test.rb b/test/mcp/resource_test.rb index 3c8ff1b..9e78012 100644 --- a/test/mcp/resource_test.rb +++ b/test/mcp/resource_test.rb @@ -36,156 +36,5 @@ module MCP assert_equal expected_icons, resource.to_h[:icons] end - - test "#to_h omits _meta when nil" do - resource = Resource.new(uri: "file:///test.txt", name: "resource_without_meta") - - refute resource.to_h.key?(:_meta) - end - - test "#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - resource = Resource.new(uri: "file:///test.txt", name: "resource_with_meta", meta: meta) - - assert_equal meta, resource.to_h[:_meta] - end - - test "#to_h omits size when nil" do - resource = Resource.new(uri: "file:///test.txt", name: "resource_without_size") - - refute resource.to_h.key?(:size) - end - - test "#to_h includes size when present" do - resource = Resource.new(uri: "file:///test.txt", name: "resource_with_size", size: 12_345) - - assert_equal 12_345, resource.to_h[:size] - end - - test "#to_h includes size when zero" do - resource = Resource.new(uri: "file:///empty.txt", name: "empty_resource", size: 0) - - assert_equal 0, resource.to_h[:size] - end - - test "#to_h omits annotations when nil" do - resource = Resource.new(uri: "file:///test.txt", name: "resource_without_annotations") - - refute resource.to_h.key?(:annotations) - end - - test "#to_h includes annotations when present" do - annotations = Annotations.new(audience: ["user"], priority: 0.8, last_modified: "2025-01-12T15:00:58Z") - resource = Resource.new(uri: "file:///test.txt", name: "resource_with_annotations", annotations: annotations) - - expected = { audience: ["user"], priority: 0.8, lastModified: "2025-01-12T15:00:58Z" } - assert_equal expected, resource.to_h[:annotations] - end - - class UserGuideResource < Resource - uri "file:///docs/user_guide.md" - title "User Guide" - description "the user guide" - icons [Icon.new(mime_type: "image/png", sizes: ["48x48"], src: "https://example.com", theme: "light")] - mime_type "text/markdown" - annotations audience: ["user"], priority: 0.5 - size 2_048 - meta({ "example" => "value" }) - - class << self - def contents - [Resource::TextContents.new(uri: uri, mime_type: mime_type, text: "guide body")] - end - end - end - - test "class-based .to_h emits the same keys as the equivalent instance" do - instance = Resource.new( - uri: "file:///docs/user_guide.md", - name: "user_guide_resource", - title: "User Guide", - description: "the user guide", - icons: [Icon.new(mime_type: "image/png", sizes: ["48x48"], src: "https://example.com", theme: "light")], - mime_type: "text/markdown", - annotations: Annotations.new(audience: ["user"], priority: 0.5), - size: 2_048, - meta: { "example" => "value" }, - ) - - assert_equal instance.to_h, UserGuideResource.to_h - end - - test "class-based name defaults to the snake_cased class name" do - assert_equal "user_guide_resource", UserGuideResource.name_value - end - - test "explicit resource_name wins over the class name" do - resource_class = Class.new(UserGuideResource) do - resource_name "custom_name" - end - - assert_equal "custom_name", resource_class.resource_name - assert_equal "custom_name", resource_class.name_value - end - - test "class-based .to_h omits keys that are not set" do - resource_class = Class.new(Resource) do - uri "file:///bare.txt" - resource_name "bare" - end - - assert_equal({ uri: "file:///bare.txt", name: "bare" }, resource_class.to_h) - end - - test "class-level annotations accepts an Annotations instance" do - annotations = Annotations.new(audience: ["assistant"]) - resource_class = Class.new(Resource) do - annotations annotations - end - - assert_same annotations, resource_class.annotations - end - - test "subclasses of a configured class start clean" do - subclass = Class.new(UserGuideResource) - - assert_nil subclass.uri - assert_nil subclass.title - assert_nil subclass.description - assert_nil subclass.icons - assert_nil subclass.mime_type - assert_nil subclass.annotations - assert_nil subclass.size - assert_nil subclass.meta - end - - test ".contents raises NotImplementedError unless implemented" do - resource_class = Class.new(Resource) - - assert_raises(NotImplementedError) { resource_class.contents } - end - - test ".define creates a resource class whose block implements contents" do - resource_class = Resource.define( - uri: "file:///defined.txt", - name: "defined_resource", - mime_type: "text/plain", - ) do - [Resource::TextContents.new(uri: uri, mime_type: mime_type, text: "defined body")] - end - - assert_equal "file:///defined.txt", resource_class.uri - assert_equal "defined_resource", resource_class.name_value - - contents = resource_class.contents - assert_equal 1, contents.size - assert_equal "defined body", contents.first.text - end - - test ".define without a name omits :name from to_h" do - resource_class = Resource.define(uri: "file:///anonymous.txt") - - refute resource_class.to_h.key?(:name) - end end end diff --git a/test/mcp/server/capabilities_test.rb b/test/mcp/server/capabilities_test.rb deleted file mode 100644 index 93e7e5f..0000000 --- a/test/mcp/server/capabilities_test.rb +++ /dev/null @@ -1,71 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Server - class CapabilitiesTest < ActiveSupport::TestCase - test "to_h omits everything by default" do - assert_empty(Capabilities.new.to_h) - end - - test "constructor accepts a capabilities hash" do - capabilities = Capabilities.new( - completions: {}, - logging: {}, - prompts: { listChanged: true }, - resources: { listChanged: true, subscribe: true }, - tools: { listChanged: true }, - ) - - assert_equal( - { - completions: {}, - logging: {}, - prompts: { listChanged: true }, - resources: { listChanged: true, subscribe: true }, - tools: { listChanged: true }, - }, - capabilities.to_h, - ) - end - - test "constructor accepts extensions" do - capabilities = Capabilities.new( - tools: {}, - extensions: { "com.example/feature" => { enabled: true } }, - ) - - assert_equal({ "com.example/feature" => { enabled: true } }, capabilities.to_h[:extensions]) - end - - test "support_extensions merges repeated declarations" do - capabilities = Capabilities.new - capabilities.support_extensions("com.example/feature" => { enabled: true }) - capabilities.support_extensions("io.modelcontextprotocol/tasks" => {}) - - assert_equal( - { "com.example/feature" => { enabled: true }, "io.modelcontextprotocol/tasks" => {} }, - capabilities.to_h[:extensions], - ) - end - - test "support_extensions with no arguments declares an empty extensions object" do - capabilities = Capabilities.new - capabilities.support_extensions - - assert_equal({}, capabilities.to_h[:extensions]) - end - - test "support_extensions tolerates nil" do - capabilities = Capabilities.new(extensions: nil) - - assert_equal({}, capabilities.to_h[:extensions]) - end - - test "to_h omits extensions when never declared" do - refute(Capabilities.new(tools: {}).to_h.key?(:extensions)) - end - end - end -end diff --git a/test/mcp/server/input_required_result_test.rb b/test/mcp/server/input_required_result_test.rb deleted file mode 100644 index ba8ce43..0000000 --- a/test/mcp/server/input_required_result_test.rb +++ /dev/null @@ -1,109 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Server - class InputRequiredResultTest < ActiveSupport::TestCase - test "requires at least one of input_requests or request_state" do - assert_raises(ArgumentError) { InputRequiredResult.new } - assert_raises(ArgumentError) { InputRequiredResult.new(input_requests: {}) } - assert_raises(ArgumentError) { InputRequiredResult.new(request_state: 42) } - end - - test "validates input_requests entries" do - assert_raises(ArgumentError) { InputRequiredResult.new(input_requests: []) } - assert_raises(ArgumentError) { InputRequiredResult.new(input_requests: { region: "not-a-hash" }) } - assert_raises(ArgumentError) do - InputRequiredResult.new(input_requests: { region: { method: "tools/call" } }) - end - assert_raises(ArgumentError) do - InputRequiredResult.new(input_requests: { region: { method: "elicitation/create", params: "x" } }) - end - end - - test "normalizes keys, tolerates string entry keys, and freezes" do - result = InputRequiredResult.new(input_requests: { - region: { "method" => "elicitation/create", "params" => { message: "Which region?" } }, - }) - - assert_predicate result, :frozen? - assert_equal ["region"], result.input_requests.keys - assert_equal "elicitation/create", result.input_requests["region"][:method] - assert_equal({ message: "Which region?" }, result.input_requests["region"][:params]) - end - - test "#to_h serializes the SEP-2322 wire shape" do - result = InputRequiredResult.new( - input_requests: { region: { method: "elicitation/create", params: { message: "Which region?" } } }, - request_state: "opaque-state", - ) - - assert_equal( - { - resultType: "input_required", - inputRequests: { "region" => { method: "elicitation/create", params: { message: "Which region?" } } }, - requestState: "opaque-state", - }, - result.to_h, - ) - end - - test "#to_h omits absent fields" do - state_only = InputRequiredResult.new(request_state: "opaque-state") - - assert_equal({ resultType: "input_required", requestState: "opaque-state" }, state_only.to_h) - end - - test "#required_client_capabilities maps every embedded request kind" do - result = InputRequiredResult.new(input_requests: { - form: { method: "elicitation/create", params: { message: "?" } }, - url: { method: "elicitation/create", params: { mode: "url", url: "https://example.com" } }, - plain_sampling: { method: "sampling/createMessage", params: { messages: [] } }, - tool_sampling: { method: "sampling/createMessage", params: { messages: [], tools: [] } }, - roots: { method: "roots/list" }, - }) - - assert_equal( - { - elicitation: { form: {}, url: {} }, - sampling: { tools: {} }, - roots: {}, - }, - result.required_client_capabilities, - ) - end - - test "#missing_client_capabilities returns only undeclared branches" do - result = InputRequiredResult.new(input_requests: { - form: { method: "elicitation/create", params: { message: "?" } }, - roots: { method: "roots/list" }, - }) - - assert_equal( - { elicitation: { form: {} }, roots: {} }, - result.missing_client_capabilities({}), - ) - assert_equal( - { roots: {} }, - result.missing_client_capabilities({ elicitation: { form: {} } }), - ) - assert_empty result.missing_client_capabilities({ "elicitation" => { "form" => {} }, "roots" => {} }) - end - - test "#missing_client_capabilities treats a bare elicitation declaration as implying form" do - # 2025 back-compat rule shared with the TypeScript and Python SDKs; an explicit - # url-only declaration does not imply form support. - result = InputRequiredResult.new(input_requests: { - form: { method: "elicitation/create", params: { message: "?" } }, - }) - - assert_empty result.missing_client_capabilities({ elicitation: {} }) - assert_equal( - { elicitation: { form: {} } }, - result.missing_client_capabilities({ elicitation: { url: {} } }), - ) - end - end - end -end diff --git a/test/mcp/server/pagination_test.rb b/test/mcp/server/pagination_test.rb deleted file mode 100644 index 4885459..0000000 --- a/test/mcp/server/pagination_test.rb +++ /dev/null @@ -1,166 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Server - class PaginationTest < ActiveSupport::TestCase - class PaginationHost - include Pagination - - # Expose private methods for testing. - public :paginate, :cursor_from - - # RequestHandlerError must be accessible. - RequestHandlerError = Server::RequestHandlerError - end - - setup do - @host = PaginationHost.new - @items = [{ name: "a" }, { name: "b" }, { name: "c" }, { name: "d" }, { name: "e" }] - @request = { method: "tools/list" } - end - - test "paginate returns all items when page_size is nil and no cursor" do - result = @host.paginate(@items, cursor: nil, page_size: nil, request: @request) - - assert_equal @items, result[:items] - assert_nil result[:next_cursor] - end - - test "paginate returns first page with nextCursor when page_size is set" do - result = @host.paginate(@items, cursor: nil, page_size: 2, request: @request) - - assert_equal [{ name: "a" }, { name: "b" }], result[:items] - assert_not_nil result[:next_cursor] - end - - test "paginate returns correct second page when cursor is provided" do - first = @host.paginate(@items, cursor: nil, page_size: 2, request: @request) - second = @host.paginate(@items, cursor: first[:next_cursor], page_size: 2, request: @request) - - assert_equal [{ name: "c" }, { name: "d" }], second[:items] - assert_not_nil second[:next_cursor] - end - - test "paginate returns last page without nextCursor" do - first = @host.paginate(@items, cursor: nil, page_size: 2, request: @request) - second = @host.paginate(@items, cursor: first[:next_cursor], page_size: 2, request: @request) - third = @host.paginate(@items, cursor: second[:next_cursor], page_size: 2, request: @request) - - assert_equal [{ name: "e" }], third[:items] - assert_nil third[:next_cursor] - end - - test "paginate with page_size equal to items count returns all without nextCursor" do - result = @host.paginate(@items, cursor: nil, page_size: 5, request: @request) - - assert_equal @items, result[:items] - assert_nil result[:next_cursor] - end - - test "paginate with page_size larger than items count returns all without nextCursor" do - result = @host.paginate(@items, cursor: nil, page_size: 100, request: @request) - - assert_equal @items, result[:items] - assert_nil result[:next_cursor] - end - - test "paginate with empty items returns empty array" do - result = @host.paginate([], cursor: nil, page_size: 2, request: @request) - - assert_equal [], result[:items] - assert_nil result[:next_cursor] - end - - test "paginate raises RequestHandlerError for non-numeric cursor" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: "not_a_number", page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate raises RequestHandlerError for Integer cursor (spec requires string)" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: 2, page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate raises RequestHandlerError for Float cursor (spec requires string)" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: 1.5, page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate raises RequestHandlerError for negative offset cursor" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: "-1", page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate raises RequestHandlerError for out-of-range cursor" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: "100", page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate returns all items from cursor offset when page_size is nil" do - result = @host.paginate(@items, cursor: "2", page_size: nil, request: @request) - - assert_equal [{ name: "c" }, { name: "d" }, { name: "e" }], result[:items] - assert_nil result[:next_cursor] - end - - test "paginate raises RequestHandlerError when cursor points exactly at items.size" do - error = assert_raises(RequestHandlerError) do - @host.paginate(@items, cursor: @items.size.to_s, page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate on empty items with any cursor raises RequestHandlerError" do - error = assert_raises(RequestHandlerError) do - @host.paginate([], cursor: "0", page_size: 2, request: @request) - end - assert_equal :invalid_params, error.error_type - end - - test "cursor_from returns nil for nil request" do - assert_nil @host.cursor_from(nil) - end - - test "cursor_from returns cursor for Hash request" do - assert_equal "abc", @host.cursor_from(cursor: "abc") - end - - test "cursor_from returns nil when Hash request has no cursor" do - assert_nil @host.cursor_from({}) - end - - test "cursor_from raises RequestHandlerError for non-Hash request" do - error = assert_raises(RequestHandlerError) do - @host.cursor_from([1, 2, 3]) - end - assert_equal :invalid_params, error.error_type - end - - test "paginate with page_size 1 iterates one item at a time" do - results = [] - cursor = nil - - loop do - page = @host.paginate(@items, cursor: cursor, page_size: 1, request: @request) - results.concat(page[:items]) - cursor = page[:next_cursor] - break unless cursor - end - - assert_equal @items, results - end - end - end -end diff --git a/test/mcp/server/request_state_security_test.rb b/test/mcp/server/request_state_security_test.rb deleted file mode 100644 index 29b7d79..0000000 --- a/test/mcp/server/request_state_security_test.rb +++ /dev/null @@ -1,90 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Server - class RequestStateSecurityTest < ActiveSupport::TestCase - include ActiveSupport::Testing::TimeHelpers - - KEY = ("k" * 32).freeze - - test "validates constructor arguments" do - assert_raises(ArgumentError) { RequestStateSecurity.new(key: "short") } - assert_raises(ArgumentError) { RequestStateSecurity.new(key: KEY, ttl: 0) } - end - - test "seals and unseals a state bound to the originating request" do - security = RequestStateSecurity.new(key: KEY, audience: "my_server") - sealed = security.seal("plain-state", method: "tools/call", target: "my_tool", arguments_digest: "digest") - - assert sealed.start_with?("v1.") - refute_includes sealed, "plain-state" - assert_equal "plain-state", - security.unseal(sealed, method: "tools/call", target: "my_tool", arguments_digest: "digest") - end - - test "rejects expired tokens" do - security = RequestStateSecurity.new(key: KEY, ttl: 60) - sealed = security.seal("state", method: "tools/call", target: "t", arguments_digest: "d") - - travel 120 do - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(sealed, method: "tools/call", target: "t", arguments_digest: "d") - end - end - end - - test "rejects claims mismatches fail-closed" do - security = RequestStateSecurity.new(key: KEY, audience: "my_server") - sealed = security.seal("state", method: "tools/call", target: "my_tool", arguments_digest: "digest") - - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(sealed, method: "prompts/get", target: "my_tool", arguments_digest: "digest") - end - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(sealed, method: "tools/call", target: "other_tool", arguments_digest: "digest") - end - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(sealed, method: "tools/call", target: "my_tool", arguments_digest: "other") - end - - other_audience = RequestStateSecurity.new(key: KEY, audience: "other_server") - assert_raises(RequestStateSecurity::InvalidStateError) do - other_audience.unseal(sealed, method: "tools/call", target: "my_tool", arguments_digest: "digest") - end - end - - test "rejects tampered and malformed tokens" do - security = RequestStateSecurity.new(key: KEY) - sealed = security.seal("state", method: "tools/call", target: "t", arguments_digest: "d") - - tampered = sealed.dup - tampered[-1] = tampered[-1] == "A" ? "B" : "A" - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(tampered, method: "tools/call", target: "t", arguments_digest: "d") - end - - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal("not-a-token", method: "tools/call", target: "t", arguments_digest: "d") - end - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal("v1.!!!", method: "tools/call", target: "t", arguments_digest: "d") - end - assert_raises(RequestStateSecurity::InvalidStateError) do - security.unseal(nil, method: "tools/call", target: "t", arguments_digest: "d") - end - end - - test "rejects tokens sealed under a different key" do - sealed = RequestStateSecurity.new(key: KEY) - .seal("state", method: "tools/call", target: "t", arguments_digest: "d") - other = RequestStateSecurity.new(key: "x" * 32) - - assert_raises(RequestStateSecurity::InvalidStateError) do - other.unseal(sealed, method: "tools/call", target: "t", arguments_digest: "d") - end - end - end - end -end diff --git a/test/mcp/server/transports/stdio_notification_integration_test.rb b/test/mcp/server/transports/stdio_notification_integration_test.rb index f0d1963..6030e4b 100644 --- a/test/mcp/server/transports/stdio_notification_integration_test.rb +++ b/test/mcp/server/transports/stdio_notification_integration_test.rb @@ -27,7 +27,7 @@ module MCP nil # Simulate end of input end - def set_encoding(encoding) + def set_encoding(encoding) # rubocop:disable Naming/AccessorMethodName # Mock implementation end @@ -61,6 +61,7 @@ module MCP resources: [], ) @transport = StdioTransport.new(@server) + @server.transport = @transport end teardown do @@ -78,12 +79,8 @@ module MCP # Test resources notification @server.notify_resources_list_changed - # Test log notification - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - # Check the notifications were sent - assert_equal 4, @mock_stdout.output.size + assert_equal 3, @mock_stdout.output.size # Parse and verify each notification notifications = @mock_stdout.output.map { |msg| JSON.parse(msg) } @@ -99,10 +96,6 @@ module MCP assert_equal "2.0", notifications[2]["jsonrpc"] assert_equal Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED, notifications[2]["method"] assert_nil notifications[2]["params"] - - assert_equal "2.0", notifications[3]["jsonrpc"] - assert_equal Methods::NOTIFICATIONS_MESSAGE, notifications[3]["method"] - assert_equal({ "level" => "error", "data" => { "error" => "Connection Failed" } }, notifications[3]["params"]) end test "notifications include params when provided" do @@ -127,7 +120,6 @@ module MCP @server.notify_tools_list_changed @server.notify_prompts_list_changed @server.notify_resources_list_changed - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") end end @@ -212,7 +204,7 @@ module MCP # This test verifies the complete integration from server to transport # Start with no output - assert_equal([], @mock_stdout.output) + assert_empty @mock_stdout.output # Add a prompt and notify @server.define_prompt( @@ -248,16 +240,6 @@ module MCP assert_equal 2, @mock_stdout.output.size second_notification = JSON.parse(@mock_stdout.output.last) assert_equal Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED, second_notification["method"] - - # Set log level and notify - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - - # Manually trigger notification - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - assert_equal 3, @mock_stdout.output.size - third_notification = JSON.parse(@mock_stdout.output.last) - assert_equal Methods::NOTIFICATIONS_MESSAGE, third_notification["method"] - assert_equal({ "data" => { "error" => "Connection Failed" }, "level" => "error" }, third_notification["params"]) end end end diff --git a/test/mcp/server/transports/stdio_transport_test.rb b/test/mcp/server/transports/stdio_transport_test.rb index 683e2ae..48acf46 100644 --- a/test/mcp/server/transports/stdio_transport_test.rb +++ b/test/mcp/server/transports/stdio_transport_test.rb @@ -7,7 +7,6 @@ module MCP module Transports class StdioTransportTest < ActiveSupport::TestCase include InstrumentationTestHelper - include InitializeParamsTestHelper setup do configuration = MCP::Configuration.new @@ -46,7 +45,7 @@ module MCP response = JSON.parse(output.string, symbolize_names: true) assert_equal("2.0", response[:jsonrpc]) assert_equal("123", response[:id]) - assert_equal({}, response[:result]) + assert_empty(response[:result]) refute(@transport.instance_variable_get(:@open)) ensure $stdin = original_stdin @@ -102,111 +101,6 @@ module MCP end end - test "open creates a ServerSession and processes requests through it" do - request = { - jsonrpc: "2.0", - method: "initialize", - id: "1", - params: { - protocolVersion: "2025-11-25", - capabilities: {}, - clientInfo: { name: "stdio-client", version: "1.0" }, - }, - } - input = StringIO.new(JSON.generate(request) + "\n") - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - @transport.open - - # Verify a session was created. - session = @transport.instance_variable_get(:@session) - assert_instance_of(ServerSession, session) - - # Verify client info was stored on the session, not on the server. - assert_equal({ name: "stdio-client", version: "1.0" }, session.client) - ensure - $stdin = original_stdin - $stdout = original_stdout - end - end - - test "open handles a malformed JSON-RPC batch element and emits an error response" do - input = StringIO.new("[[]]\n") - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - @transport.open - - response = JSON.parse(output.string, symbolize_names: true) - assert_nil(response[:id]) - assert_equal(-32600, response[:error][:code]) - assert_equal("Invalid Request", response[:error][:message]) - ensure - $stdin = original_stdin - $stdout = original_stdout - end - end - - test "rejects duplicate initialize on the same stdio session with -32600" do - first = { - jsonrpc: "2.0", - method: "initialize", - id: "first", - params: { - protocolVersion: "2025-11-25", - capabilities: {}, - clientInfo: { name: "original", version: "1.0" }, - }, - } - second = { - jsonrpc: "2.0", - method: "initialize", - id: "second", - params: { - protocolVersion: "2024-11-05", - capabilities: {}, - clientInfo: { name: "intruder", version: "9.9" }, - }, - } - input = StringIO.new("#{JSON.generate(first)}\n#{JSON.generate(second)}\n") - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - @transport.open - - lines = output.string.lines - assert_equal(2, lines.length) - first_response = JSON.parse(lines[0], symbolize_names: true) - second_response = JSON.parse(lines[1], symbolize_names: true) - - assert_equal("first", first_response[:id]) - refute_nil(first_response[:result]) - - assert_equal("second", second_response[:id]) - assert_equal(-32600, second_response[:error][:code]) - assert_equal("Invalid Request", second_response[:error][:message]) - - session = @transport.instance_variable_get(:@session) - assert_equal({ name: "original", version: "1.0" }, session.client) - ensure - $stdin = original_stdin - $stdout = original_stdout - end - end - test "handles invalid JSON requests" do invalid_json = "invalid json" output = StringIO.new @@ -225,526 +119,6 @@ module MCP $stdout = original_stdout end end - - test "send_request sends request to stdout and waits for response" do - reader, writer = IO.pipe - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = reader - $stdout = output - @transport.instance_variable_set(:@open, true) - - # Send response from client in a thread. - Thread.new do - sleep(0.05) # Wait for request to be written to `StringIO`. - request = JSON.parse(output.string.lines.first, symbolize_names: true) - response = { - jsonrpc: "2.0", - id: request[:id], - result: { content: "test response" }, - } - writer.puts(response.to_json) - writer.flush - end - - result = @transport.send_request("test/method", { param: "value" }) - - assert_equal({ content: "test response" }, result) - - # Verify request was sent. - request = JSON.parse(output.string.lines.first, symbolize_names: true) - assert_equal("2.0", request[:jsonrpc]) - assert_equal("test/method", request[:method]) - assert_equal({ param: "value" }, request[:params]) - assert(request[:id]) - ensure - $stdin = original_stdin - $stdout = original_stdout - begin - writer.close - rescue - nil - end - begin - reader.close - rescue - nil - end - end - end - - test "send_request raises on error response from client" do - reader, writer = IO.pipe - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = reader - $stdout = output - @transport.instance_variable_set(:@open, true) - - Thread.new do - sleep(0.05) # Wait for request to be written to `StringIO`. - request = JSON.parse(output.string.lines.first, symbolize_names: true) - error_response = { - jsonrpc: "2.0", - id: request[:id], - error: { code: -1, message: "User rejected sampling request" }, - } - writer.puts(error_response.to_json) - writer.flush - end - - error = assert_raises(StandardError) do - @transport.send_request("sampling/createMessage", { messages: [] }) - end - - assert_equal("Client returned an error for sampling/createMessage request (code: -1): User rejected sampling request", error.message) - ensure - $stdin = original_stdin - $stdout = original_stdout - begin - writer.close - rescue - nil - end - begin - reader.close - rescue - nil - end - end - end - - test "send_request does not double-report intentional raises via exception_reporter" do - reader, writer = IO.pipe - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - reported_errors = [] - original_reporter = MCP.configuration.exception_reporter - - begin - MCP.configuration.exception_reporter = ->(e, ctx) { reported_errors << [e, ctx] } - $stdin = reader - $stdout = output - @transport.instance_variable_set(:@open, true) - - Thread.new do - sleep(0.05) # Wait for request to be written to `StringIO`. - request = JSON.parse(output.string.lines.first, symbolize_names: true) - error_response = { - jsonrpc: "2.0", - id: request[:id], - error: { code: -1, message: "rejected" }, - } - writer.puts(error_response.to_json) - writer.flush - end - - assert_raises(StandardError) do - @transport.send_request("sampling/createMessage", { messages: [] }) - end - - assert_empty(reported_errors) - ensure - MCP.configuration.exception_reporter = original_reporter - $stdin = original_stdin - $stdout = original_stdout - begin - writer.close - rescue - nil - end - begin - reader.close - rescue - nil - end - end - end - - test "send_request processes interleaved requests via session" do - reader, writer = IO.pipe - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = reader - $stdout = output - @transport.instance_variable_set(:@open, true) - - # Initialize a session so @session is set. - session = MCP::ServerSession.new(server: @server, transport: @transport) - @transport.instance_variable_set(:@session, session) - - Thread.new do - sleep(0.05) # Wait for request to be written to `StringIO`. - request = JSON.parse(output.string.lines.first, symbolize_names: true) - - # Send an interleaved ping request before the response. - ping = { jsonrpc: "2.0", method: "ping", id: "ping-1" } - writer.puts(ping.to_json) - writer.flush - - sleep(0.05) # Wait for the ping to be processed. - - # Then send the actual response. - response = { - jsonrpc: "2.0", - id: request[:id], - result: { content: "done" }, - } - writer.puts(response.to_json) - writer.flush - end - - result = @transport.send_request("test/method", { param: "value" }) - - assert_equal({ content: "done" }, result) - - # Verify the interleaved ping was handled (response sent to output). - lines = output.string.lines - ping_response = lines.find { |l| l.include?("ping-1") } - assert(ping_response, "Interleaved ping request should have been handled") - ensure - $stdin = original_stdin - $stdout = original_stdout - begin - writer.close - rescue - nil - end - begin - reader.close - rescue - nil - end - end - end - - test "send_request raises when transport is closed while waiting" do - reader, writer = IO.pipe - output = StringIO.new - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = reader - $stdout = output - @transport.instance_variable_set(:@open, true) - - # Close transport while waiting for response. - Thread.new do - sleep(0.05) # Wait for request to be written to `StringIO`. - @transport.instance_variable_set(:@open, false) - writer.close - end - - error = assert_raises(RuntimeError) do - @transport.send_request("sampling/createMessage", { messages: [] }) - end - - assert_equal("Transport closed while waiting for response to sampling/createMessage request.", error.message) - ensure - $stdin = original_stdin - $stdout = original_stdout - begin - writer.close - rescue IOError - nil - end - begin - reader.close - rescue IOError - nil - end - end - end - - test "raises ArgumentError when max_line_bytes is not a positive Integer" do - [nil, 0, -1, 1.5, "1024"].each do |invalid| - error = assert_raises(ArgumentError) do - StdioTransport.new(@server, max_line_bytes: invalid) - end - assert_equal("max_line_bytes must be a positive Integer", error.message) - end - end - - test "open stops and reports when a stdin frame exceeds max_line_bytes without a newline" do - transport = StdioTransport.new(@server, max_line_bytes: 64) - input = StringIO.new("A" * 200) # No newline: an unbounded frame. - output = StringIO.new - - reported = [] - original_stdin = $stdin - original_stdout = $stdout - original_reporter = MCP.configuration.exception_reporter - - begin - $stdin = input - $stdout = output - MCP.configuration.exception_reporter = ->(e, ctx) { reported << [e, ctx] } - - transport.open - - refute(transport.instance_variable_get(:@open)) - assert_equal(1, reported.size) - error, _ctx = reported.first - assert_instance_of(RequestHandlerError, error) - assert_match(/exceeds 64 bytes without a newline/, error.message) - ensure - $stdin = original_stdin - $stdout = original_stdout - MCP.configuration.exception_reporter = original_reporter - end - end - - test "open processes a valid final frame that ends at EOF without a trailing newline" do - request = { jsonrpc: "2.0", method: "ping", id: "eof" } - input = StringIO.new(JSON.generate(request)) # No trailing newline. - output = StringIO.new - - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - - @transport.open - - response = JSON.parse(output.string, symbolize_names: true) - assert_equal("eof", response[:id]) - assert_equal({}, response[:result]) - ensure - $stdin = original_stdin - $stdout = original_stdout - end - end - - test "send_request raises when a response frame exceeds max_line_bytes without a newline" do - transport = StdioTransport.new(@server, max_line_bytes: 64) - input = StringIO.new("A" * 200) # No newline: an unbounded frame. - output = StringIO.new - - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - transport.instance_variable_set(:@open, true) - - error = assert_raises(RequestHandlerError) do - transport.send_request("sampling/createMessage", { messages: [] }) - end - - assert_match(/exceeds 64 bytes without a newline/, error.message) - ensure - $stdin = original_stdin - $stdout = original_stdout - end - end - - test "locks the legacy era on a successful initialize and rejects a later modern envelope" do - responses = run_transport_session([ - initialize_request(id: 1), - modern_tools_list_request(id: 2), - ]) - - refute responses[0].key?(:error) - assert_equal :legacy, session_era - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, responses[1].dig(:error, :code) - end - - test "initialize requesting 2026-07-28 is counter-offered 2025-11-25 and locks the legacy era" do - # Per the SEP-2575 era model, the handshake never lands on a modern version; the connection proceeds on - # the legacy lifecycle it selected, so a later modern envelope is still rejected. - responses = run_transport_session([ - initialize_request(id: 1, protocol_version: "2026-07-28"), - modern_tools_list_request(id: 2), - ]) - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, responses[0].dig(:result, :protocolVersion) - assert_equal :legacy, session_era - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, responses[1].dig(:error, :code) - end - - test "locks the modern era on a successful server/discover and rejects a later initialize with -32601" do - responses = run_transport_session([ - { jsonrpc: "2.0", method: "server/discover", id: 1 }, - initialize_request(id: 2), - modern_tools_list_request(id: 3), - ]) - - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, responses[0].dig(:result, :supportedVersions) - assert_equal :modern, session_era - # SEP-2575 removes `initialize` from the modern lifecycle, so a modern-locked connection - # answers it with Method not found. - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, responses[1].dig(:error, :code) - refute responses[2].key?(:error) - end - - test "locks the modern era on a successful request carrying the modern envelope" do - responses = run_transport_session([modern_tools_list_request(id: 1)]) - - refute responses[0].key?(:error) - assert_equal :modern, session_era - end - - test "rejects a removed lifecycle method carrying the envelope as the connection's first frame" do - # The era locks only after a response succeeds, so this frame reaches the server unlocked. - # SEP-2575 removed `resources/subscribe`, and the envelope is what identifies the request as modern. - responses = run_transport_session([ - { - jsonrpc: "2.0", - method: "resources/subscribe", - id: 1, - params: { - uri: "https://example.invalid/resource", - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - }, - }, - }, - ]) - - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, responses[0].dig(:error, :code) - refute_equal :legacy, session_era - end - - test "does not lock an era when the era-distinctive request fails" do - # An unsupported envelope version fails with -32022, so the connection stays unlocked - # and a legacy initialize can still succeed afterwards. - responses = run_transport_session([ - modern_tools_list_request(id: 1, version: "2027-01-01"), - initialize_request(id: 2), - ]) - - assert_equal ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, responses[0].dig(:error, :code) - refute responses[1].key?(:error) - assert_equal :legacy, session_era - end - - test "requires the modern envelope after a modern era lock" do - responses = run_transport_session([ - modern_tools_list_request(id: 1), - { jsonrpc: "2.0", method: "tools/list", id: 2 }, - ]) - - refute responses[0].key?(:error) - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, responses[1].dig(:error, :code) - end - - test "answers removed lifecycle methods with -32601 after a modern era lock" do - removed_requests = Methods::MODERN_REMOVED_METHODS.each_with_index.map do |method, index| - { jsonrpc: "2.0", method: method, id: index + 2 } - end - responses = run_transport_session([modern_tools_list_request(id: 1)] + removed_requests) - - refute responses[0].key?(:error) - responses[1..].each_with_index do |response, index| - method = Methods::MODERN_REMOVED_METHODS[index] - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code), "expected -32601 for #{method}" - end - end - - test "subscriptions/listen is not served over stdio and answers -32601" do - # Like the Python SDK, the stream-pair transport does not serve the SEP-2575 notification subscription stream. - listen = { - jsonrpc: "2.0", - method: "subscriptions/listen", - id: "listen-1", - params: { - notifications: { toolsListChanged: true }, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - }, - }, - } - - responses = run_transport_session([listen]) - - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, responses[0].dig(:error, :code) - end - - test "#send_request raises on a modern-locked session" do - run_transport_session([modern_tools_list_request(id: 1)]) - - error = assert_raises(RuntimeError) do - @transport.send_request("roots/list") - end - assert_match(/modern lifecycle/, error.message) - end - - private - - def initialize_request(id:, protocol_version: "2025-11-25") - { - jsonrpc: "2.0", - method: "initialize", - id: id, - params: initialize_params( - protocolVersion: protocol_version, - clientInfo: { name: "legacy_client", version: "1.0" }, - ), - } - end - - # `tools/list` stands in as the era-distinctive modern request: `ping` cannot, - # because SEP-2575 removes it from the modern lifecycle (-32601 there). - def modern_tools_list_request(id:, version: "2026-07-28") - { - jsonrpc: "2.0", - method: "tools/list", - id: id, - params: { - _meta: { - "io.modelcontextprotocol/protocolVersion": version, - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - }, - }, - } - end - - # Feeds the frames to a fresh transport session over swapped stdio and returns the parsed responses in order. - def run_transport_session(frames) - input = StringIO.new(frames.map { |frame| JSON.generate(frame) }.join("\n") + "\n") - output = StringIO.new - - original_stdin = $stdin - original_stdout = $stdout - - begin - $stdin = input - $stdout = output - - thread = Thread.new { @transport.open } - sleep(0.1) - @transport.close - thread.join - ensure - $stdin = original_stdin - $stdout = original_stdout - end - - output.string.each_line.map { |line| JSON.parse(line, symbolize_names: true) } - end - - def session_era - @transport.instance_variable_get(:@session).era - end end end end diff --git a/test/mcp/server/transports/streamable_http_notification_integration_test.rb b/test/mcp/server/transports/streamable_http_notification_integration_test.rb index e1a37a5..4e926ae 100644 --- a/test/mcp/server/transports/streamable_http_notification_integration_test.rb +++ b/test/mcp/server/transports/streamable_http_notification_integration_test.rb @@ -7,8 +7,6 @@ module MCP class Server module Transports class StreamableHTTPNotificationIntegrationTest < ActiveSupport::TestCase - include InitializeParamsTestHelper - setup do @server = Server.new( name: "test_server", @@ -17,6 +15,7 @@ module MCP resources: [], ) @transport = StreamableHTTPTransport.new(@server) + @server.transport = @transport end test "server notification methods send SSE notifications through HTTP transport" do @@ -25,10 +24,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new @@ -52,12 +51,6 @@ module MCP # Test resources notification @server.notify_resources_list_changed - # Set log level to error for log notification - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - - # Test log notification - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - # Check the notifications were received io.rewind output = io.read @@ -65,7 +58,6 @@ module MCP assert_includes output, "data: {\"jsonrpc\":\"2.0\",\"method\":\"#{Methods::NOTIFICATIONS_TOOLS_LIST_CHANGED}\"}" assert_includes output, "data: {\"jsonrpc\":\"2.0\",\"method\":\"#{Methods::NOTIFICATIONS_PROMPTS_LIST_CHANGED}\"}" assert_includes output, "data: {\"jsonrpc\":\"2.0\",\"method\":\"#{Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED}\"}" - assert_includes output, "data: {\"jsonrpc\":\"2.0\",\"method\":\"#{Methods::NOTIFICATIONS_MESSAGE}\",\"params\":{\"data\":{\"error\":\"Connection Failed\"},\"level\":\"error\"}}\n\n" end test "notifications are broadcast to all connected sessions" do @@ -74,19 +66,19 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response1 = @transport.handle_request(init_request1) - session_id1 = init_response1[1]["mcp-session-id"] + session_id1 = init_response1[1]["Mcp-Session-Id"] init_request2 = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "456", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "456" }.to_json, ) init_response2 = @transport.handle_request(init_request2) - session_id2 = init_response2[1]["mcp-session-id"] + session_id2 = init_response2[1]["Mcp-Session-Id"] # Connect both sessions with SSE io1 = StringIO.new @@ -129,10 +121,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new @@ -155,7 +147,6 @@ module MCP @server.notify_tools_list_changed @server.notify_prompts_list_changed @server.notify_resources_list_changed - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") end end @@ -165,10 +156,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new @@ -209,10 +200,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new diff --git a/test/mcp/server/transports/streamable_http_transport_test.rb b/test/mcp/server/transports/streamable_http_transport_test.rb index bf032b2..55bae1c 100644 --- a/test/mcp/server/transports/streamable_http_transport_test.rb +++ b/test/mcp/server/transports/streamable_http_transport_test.rb @@ -7,33 +7,6 @@ module MCP class Server module Transports class StreamableHTTPTransportTest < ActiveSupport::TestCase - include InitializeParamsTestHelper - - # A stream that buffers writes and remains readable after close. - class TestStream - def initialize - @buffer = "".dup - @closed = false - end - - def write(data) - raise IOError, "closed stream" if @closed - - @buffer << data - end - - def flush - end - - def close - @closed = true - end - - def string - @buffer - end - end - setup do @server = Server.new( name: "test_server", @@ -41,13 +14,7 @@ module MCP prompts: [], resources: [], ) - # Disable the listen keepalive by default so opening a listen stream in a test does not - # spawn a background timer thread; the keepalive is exercised by its own dedicated tests. - @transport = StreamableHTTPTransport.new(@server, listen_keepalive_interval: nil) - end - - teardown do - @transport.close + @transport = StreamableHTTPTransport.new(@server) end test "handles POST request with valid JSON-RPC message" do @@ -56,10 +23,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Now make the ping request with the session ID request = create_rack_request( @@ -74,87 +41,12 @@ module MCP response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] + assert_equal({ "Content-Type" => "application/json" }, response[1]) - io = StringIO.new - response[2].call(io) - body = JSON.parse(io.string.match(/^data: (.+)$/)[1]) + body = JSON.parse(response[2][0]) assert_equal "2.0", body["jsonrpc"] assert_equal "123", body["id"] - assert_equal({}, body["result"]) - end - - test "response header names are lowercase as required by the Rack 3 spec" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - delete_request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - parse_error_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - "invalid json", - ) - - responses = { - initialize: init_response, - get_sse: @transport.handle_request(get_request), - delete: @transport.handle_request(delete_request), - parse_error: @transport.handle_request(parse_error_request), - } - - responses.each do |name, (_status, headers, _body)| - headers.each_key do |key| - assert_equal key.downcase, key, "#{name} response header `#{key}` must be lowercase" - end - end - end - - test "id-bearing notification message is rejected with Method not found" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "notifications/cancelled", id: "123" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - - io = StringIO.new - response[2].call(io) - body = JSON.parse(io.string.match(/^data: (.+)$/)[1]) - - assert_equal "123", body["id"] - refute body.key?("result") - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, body["error"]["code"] + assert_empty(body["result"]) end test "handles POST request with invalid JSON" do @@ -167,69 +59,10 @@ module MCP response = @transport.handle_request(request) assert_equal 400, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::PARSE_ERROR, body["error"]["code"] - assert_equal "Parse error: Invalid JSON", body["error"]["message"] - end - - test "POST request with JSON array body returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - [{ jsonrpc: "2.0", method: "tools/list", id: "list" }].to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - - body = JSON.parse(response[2][0]) - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_match(/single request object/i, body["error"]["message"]) - end - - test "POST request with non-object JSON body returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - "\"foo\"", - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - - body = JSON.parse(response[2][0]) - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_match(/single request object/i, body["error"]["message"]) + assert_equal "Invalid JSON", body["error"] end test "handles POST request with initialize method" do @@ -237,160 +70,18 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "application/json", response[1]["content-type"] - assert response[1]["mcp-session-id"] + assert_equal "application/json", response[1]["Content-Type"] + assert response[1]["Mcp-Session-Id"] body = JSON.parse(response[2][0]) assert_equal "2.0", body["jsonrpc"] assert_equal "123", body["id"] - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, body["result"]["protocolVersion"] - end - - test "rejects duplicate initialize with existing Mcp-Session-Id and preserves session" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "first", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - assert session_id - - duplicate_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "initialize", id: "second", params: initialize_params }.to_json, - ) - duplicate_response = @transport.handle_request(duplicate_request) - - assert_equal 400, duplicate_response[0] - body = JSON.parse(duplicate_response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_equal "second", body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_match(/already initialized/i, body["error"]["message"]) - - # Original session should still be usable. - ping_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "ping", id: "ping-1" }.to_json, - ) - ping_response = @transport.handle_request(ping_request) - assert_equal 200, ping_response[0] - end - - test "rejects initialize with stale Mcp-Session-Id with 404" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => "unknown-session" }, - { jsonrpc: "2.0", method: "initialize", id: "1", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 404, response[0] - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Session not found", body["error"]["message"] - end - - test "rejects duplicate initialize against an idle-expired session with 404 and evicts it" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.05) - begin - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "first", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - assert(session_id) - - sleep(0.1) - - duplicate_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "initialize", id: "second", params: initialize_params }.to_json, - ) - duplicate_response = transport.handle_request(duplicate_request) - - assert_equal(404, duplicate_response[0]) - body = JSON.parse(duplicate_response[2][0]) - assert_equal("Session not found", body["error"]["message"]) - - refute(transport.send(:session_exists?, session_id), "expired session must be evicted") - ensure - transport.close - end - end - - test "evicts session and omits Mcp-Session-Id when initialize fails" do - # An `initialize` whose JSON-RPC envelope is rejected (e.g. wrong `jsonrpc` version) - # never reaches `Server#init`, so `mark_initialized!` is never called. The transport - # must drop the registered-but-uninitialized session to keep retries clean. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "1.0", method: "initialize", id: "broken" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - refute response[1].key?("mcp-session-id"), "no session id should leak from a failed init" - - body = JSON.parse(response[2][0]) - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal({}, @transport.instance_variable_get(:@sessions)) - end - - test "acks an initialize sent without an id and retains no session" do - # `initialize` framed as a notification (no id) produces no JSON-RPC response. - # The transport must not put nil in the Rack body or retain the orphaned session. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize" }.to_json, - ) - - response = @transport.handle_request(request) - - assert_equal 202, response[0] - refute response[1].key?("mcp-session-id"), "no session id should leak from an id-less init" - assert_equal [], response[2] - assert_equal({}, @transport.instance_variable_get(:@sessions)) - end - - test "rejects non-Hash JSON-RPC body with HTTP 400 and -32600" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - [{ jsonrpc: "2.0", method: "initialize", id: "batched", params: initialize_params }].to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_match(/single request object/i, body["error"]["message"]) + assert_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, body["result"]["protocolVersion"] end test "handles GET request with valid session ID" do @@ -399,10 +90,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Then try to connect with GET request = create_rack_request( @@ -415,21 +106,22 @@ module MCP response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] + assert_equal "text/event-stream", response[1]["Content-Type"] assert response[2].is_a?(Proc) # The body should be a Proc for streaming end - test "handles POST request as SSE even when GET SSE stream is closed" do + test "handles POST request when IOError raised" do + # Create and initialize a session init_request = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] - # Connect with SSE then close it + # Connect with SSE io = StringIO.new get_request = create_rack_request( "GET", @@ -438,10 +130,13 @@ module MCP ) response = @transport.handle_request(get_request) response[2].call(io) if response[2].is_a?(Proc) + + # Give the stream time to set up sleep(0.1) + + # Close the stream io.close - # POST request should still return SSE response via POST response stream request = create_rack_request( "POST", "/", @@ -452,23 +147,30 @@ module MCP { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, ) + # This should handle IOError and return the original response response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] + assert_equal({ "Content-Type" => "application/json" }, response[1]) + + # Verify session was cleaned up + assert_not @transport.instance_variable_get(:@sessions).key?(session_id) end - test "handles POST request as SSE even when GET SSE stream has EPIPE" do + test "handles POST request when Errno::EPIPE raised" do + # Create and initialize a session init_request = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] - # Connect GET SSE with a broken pipe + # Create a pipe to simulate EPIPE condition reader, writer = IO.pipe + + # Connect with SSE using the writer end of the pipe get_request = create_rack_request( "GET", "/", @@ -476,55 +178,13 @@ module MCP ) response = @transport.handle_request(get_request) response[2].call(writer) if response[2].is_a?(Proc) + + # Give the stream time to set up sleep(0.1) + + # Close the reader end to break the pipe - this will cause EPIPE on write reader.close - # POST request should still return SSE response via POST response stream - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "789" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal(200, response[0]) - assert_equal("text/event-stream", response[1]["content-type"]) - ensure - begin - writer.close - rescue StandardError - nil - end - end - - test "handles POST request as SSE even when GET SSE stream has ECONNRESET" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE with a mock that raises ECONNRESET - mock_stream = Object.new - mock_stream.define_singleton_method(:write) { |_data| raise Errno::ECONNRESET } - mock_stream.define_singleton_method(:close) {} - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(mock_stream) if response[2].is_a?(Proc) - sleep(0.1) - - # POST request should still return SSE response via POST response stream request = create_rack_request( "POST", "/", @@ -535,9 +195,19 @@ module MCP { jsonrpc: "2.0", method: "ping", id: "789" }.to_json, ) + # This should handle Errno::EPIPE and return the original response response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] + assert_equal({ "Content-Type" => "application/json" }, response[1]) + + # Verify session was cleaned up + assert_not @transport.instance_variable_get(:@sessions).key?(session_id) + + begin + writer.close + rescue + nil + end end test "handles GET request with missing session ID" do @@ -549,198 +219,10 @@ module MCP response = @transport.handle_request(request) assert_equal 400, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Missing session ID", body["error"]["message"] - end - - test "rejects POST request without session ID in stateful mode" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Missing session ID", body["error"]["message"] - end - - test "rejects notification without session ID in stateful mode" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "notifications/initialized" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Missing session ID", body["error"]["message"] - end - - test "rejects notification with an unknown session ID in stateful mode" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => "does-not-exist" }, - { jsonrpc: "2.0", method: "notifications/initialized" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 404, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - - test "accepts a notification carrying a live session ID in stateful mode" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = @transport.handle_request(init_request)[1]["mcp-session-id"] - - notification = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "notifications/initialized" }.to_json, - ) - - response = @transport.handle_request(notification) - assert_equal 202, response[0] - end - - test "rejects response without session ID in stateful mode" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", id: "1", result: {} }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Missing session ID", body["error"]["message"] - end - - test "allows POST request without session ID in stateless mode" do - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - response = stateless_transport.handle_request(request) - assert_equal 200, response[0] - end - - test "allows server/discover POST without session ID in stateful mode" do - # Per SEP-2575, `server/discover` is sessionless capability discovery and is exempt - # from the session requirement, like `initialize`. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "server/discover", id: "1" }.to_json, - ) - - response = @transport.handle_request(request) - - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions") - refute response[1].key?("mcp-session-id") - end - - test "allows server/discover POST without session ID in stateless mode" do - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "server/discover", id: "1" }.to_json, - ) - - response = stateless_transport.handle_request(request) - - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions") - end - - test "rejects duplicate SSE connection with 409" do - # Create a session - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Simulate an active SSE stream by storing a stream object in the session - mock_stream = StringIO.new - @transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] = mock_stream - - # Attempt a second GET request for the same session - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - - response = @transport.handle_request(get_request) - assert_equal 409, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) - - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Conflict: Only one SSE stream is allowed per session", body["error"]["message"] - end - - test "store_stream_for_session does not overwrite existing stream (TOCTOU guard)" do - # Create a session - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Establish stream A - stream_a = StringIO.new - @transport.send(:store_stream_for_session, session_id, stream_a) - assert_equal stream_a, @transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] - - # Attempt to store stream B (simulating a racing request) - stream_b = StringIO.new - @transport.send(:store_stream_for_session, session_id, stream_b) - - # Stream A should still be the active stream - assert_equal stream_a, @transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] - - # Stream B should have been closed - assert stream_b.closed? + assert_equal "Missing session ID", body["error"] end test "handles GET request with invalid session ID" do @@ -752,29 +234,10 @@ module MCP response = @transport.handle_request(request) assert_equal 404, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - - test "handles POST request with invalid session ID" do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => "invalid_id", - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 404, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) - - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] + assert_equal "Session not found", body["error"] end test "handles DELETE request with valid session ID" do @@ -783,10 +246,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Then try to delete it request = create_rack_request( @@ -797,90 +260,12 @@ module MCP response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) assert body["success"] end - test "handles DELETE request with invalid session ID" do - request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => "invalid_id" }, - ) - - response = @transport.handle_request(request) - assert_equal 404, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) - - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - - test "POST returns 404 after session is deleted" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - delete_request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - @transport.handle_request(delete_request) - - post_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - response = @transport.handle_request(post_request) - assert_equal 404, response[0] - - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - - test "DELETE returns 404 after session is already deleted" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - first_delete = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(first_delete) - assert_equal 200, response[0] - - second_delete = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(second_delete) - assert_equal 404, response[0] - - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - test "handles DELETE request with missing session ID" do request = create_rack_request( "DELETE", @@ -890,10 +275,10 @@ module MCP response = @transport.handle_request(request) assert_equal 400, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "Missing session ID", body["error"]["message"] + assert_equal "Missing session ID", body["error"] end test "closes transport and cleans up session" do @@ -902,10 +287,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Then connect with GET io = StringIO.new @@ -930,77 +315,29 @@ module MCP @transport.close # Verify session was cleaned up - assert_equal({}, @transport.instance_variable_get(:@sessions)) - end - - test "cleanup_session_unsafe closes request_streams" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Simulate multiple request_streams being set on the session. - closed = [] - 2.times do |i| - mock_stream = Object.new - mock_stream.define_singleton_method(:close) { closed << i } - thread = Thread.new {} - thread.join - @transport.instance_variable_get(:@sessions)[session_id][:post_request_streams] ||= {} - @transport.instance_variable_get(:@sessions)[session_id][:post_request_streams][thread] = mock_stream - end - - delete_request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - @transport.handle_request(delete_request) - - assert_equal [0, 1], closed.sort assert_empty @transport.instance_variable_get(:@sessions) end - test "broadcast notification skips sessions without GET SSE stream" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - @transport.handle_request(init_request) - - # No GET SSE stream connected, only request_streams. - # Pass **{} to prevent Ruby 2.7 from converting the Hash to keyword arguments. - result = @transport.send_notification("test/notify", { message: "hello" }, **{}) - - assert_equal 0, result - end - test "sends notification to correct session with multiple active sessions" do # Create first session init_request1 = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response1 = @transport.handle_request(init_request1) - session_id1 = init_response1[1]["mcp-session-id"] + session_id1 = init_response1[1]["Mcp-Session-Id"] # Create second session init_request2 = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "456", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "456" }.to_json, ) init_response2 = @transport.handle_request(init_request2) - session_id2 = init_response2[1]["mcp-session-id"] + session_id2 = init_response2[1]["Mcp-Session-Id"] # Connect first session with GET io1 = StringIO.new @@ -1048,16 +385,15 @@ module MCP # Monkey-patch handle_json on the server to send a notification when called original_handle_json = @server.method(:handle_json) transport = @transport # Capture the transport in a local variable - @server.define_singleton_method(:handle_json) do |request, **kwargs| - result = original_handle_json.call(request, **kwargs) + @server.define_singleton_method(:handle_json) do |request| + result = original_handle_json.call(request) # Send notification while still in request context - broadcast to all sessions transport.send_notification("test_notification", { session: "current" }, **{}) result end - # Handle request from session 1 (execute SSE proc) - response1 = @transport.handle_request(request_as_session1) - response1[2].call(StringIO.new) if response1[2].is_a?(Proc) + # Handle request from session 1 + @transport.handle_request(request_as_session1) # Make a request as session 2 request_as_session2 = create_rack_request( @@ -1070,17 +406,18 @@ module MCP { jsonrpc: "2.0", method: "ping", id: "890" }.to_json, ) - # Handle request from session 2 (execute SSE proc) - response2_post = @transport.handle_request(request_as_session2) - response2_post[2].call(StringIO.new) if response2_post[2].is_a?(Proc) + # Handle request from session 2 + @transport.handle_request(request_as_session2) - # Broadcast notifications are sent to GET SSE streams (no related_request_id) + # Check that each session received one notification io1.rewind output1 = io1.read + # Session 1 should have received two notifications (one from each request since we broadcast) assert_equal 2, output1.scan(/data: {"jsonrpc":"2.0","method":"test_notification","params":{"session":"current"}}/).count io2.rewind output2 = io2.read + # Session 2 should have received two notifications (one from each request since we broadcast) assert_equal 2, output2.scan(/data: {"jsonrpc":"2.0","method":"test_notification","params":{"session":"current"}}/).count end @@ -1090,10 +427,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new @@ -1126,19 +463,19 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response1 = @transport.handle_request(init_request1) - session_id1 = init_response1[1]["mcp-session-id"] + session_id1 = init_response1[1]["Mcp-Session-Id"] init_request2 = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "456", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "456" }.to_json, ) init_response2 = @transport.handle_request(init_request2) - session_id2 = init_response2[1]["mcp-session-id"] + session_id2 = init_response2[1]["Mcp-Session-Id"] # Connect both sessions with SSE io1 = StringIO.new @@ -1190,10 +527,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] # Connect with SSE io = StringIO.new @@ -1221,322 +558,6 @@ module MCP assert_not @transport.instance_variable_get(:@sessions).key?(session_id) end - test "send_notification handles Errno::ECONNRESET gracefully" do - # Create and initialize a session. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Use a mock stream that raises Errno::ECONNRESET on write. - mock_stream = Object.new - mock_stream.define_singleton_method(:write) { |_data| raise Errno::ECONNRESET } - mock_stream.define_singleton_method(:close) {} - - # Connect with SSE using the mock stream. - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(mock_stream) if response[2].is_a?(Proc) - - # Give the stream time to set up. - sleep(0.1) - - # Try to send notification - should handle ECONNRESET without raising. - result = @transport.send_notification("test", { message: "test" }, session_id: session_id) - - # Should return false and clean up the session. - refute result - - # Verify session was cleaned up. - assert_not @transport.instance_variable_get(:@sessions).key?(session_id) - end - - test "send_notification closes stream outside mutex on write error" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Use a mock stream that verifies mutex is NOT held during close. - mutex = @transport.instance_variable_get(:@mutex) - closed_outside_mutex = false - mock_stream = Object.new - mock_stream.define_singleton_method(:write) { |_data| raise Errno::EPIPE } - mock_stream.define_singleton_method(:close) do - if mutex.try_lock - closed_outside_mutex = true - mutex.unlock - end - end - - @transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] = mock_stream - - result = @transport.send_notification("test", { message: "test" }, session_id: session_id) - - refute result - assert closed_outside_mutex, "Stream should be closed outside the mutex" - assert_not @transport.instance_variable_get(:@sessions).key?(session_id) - end - - test "send_notification on broken request_stream removes only that stream, not the session" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - sleep(0.1) - - # Simulate a broken request_stream. - broken_stream = Object.new - broken_stream.define_singleton_method(:write) { |_data| raise Errno::EPIPE } - broken_stream.define_singleton_method(:close) {} - related_id = "req-1" - @transport.instance_variable_get(:@sessions)[session_id][:post_request_streams] = { related_id => broken_stream } - - result = @transport.send_notification("test", { msg: "hello" }, session_id: session_id, related_request_id: related_id) - - refute result - # Session should still exist. - assert @transport.instance_variable_get(:@sessions).key?(session_id) - # The broken request_stream should be removed. - refute @transport.instance_variable_get(:@sessions)[session_id][:post_request_streams].key?(related_id) - # GET SSE stream should still be intact. - assert @transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] - end - - test "active_stream does not fall back to GET SSE when related_request_id is given but request_stream is missing" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - sleep(0.1) - - # Send notification with a related_request_id that has no matching request_stream. - result = @transport.send_notification( - "test/notify", - { message: "should not arrive" }, - session_id: session_id, - related_request_id: "nonexistent-request-id", - ) - - # Should return false because no matching request_stream exists. - refute result - - # Session should still exist (not cleaned up). - assert @transport.instance_variable_get(:@sessions).key?(session_id) - - # GET SSE stream should NOT have received the notification. - io.rewind - refute_includes io.read, "should not arrive" - end - - test "send_notification broadcast continues when one session raises Errno::ECONNRESET" do - # Create two sessions. - init_request1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "1", params: initialize_params }.to_json, - ) - init_response1 = @transport.handle_request(init_request1) - session_id1 = init_response1[1]["mcp-session-id"] - - init_request2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "2", params: initialize_params }.to_json, - ) - init_response2 = @transport.handle_request(init_request2) - session_id2 = init_response2[1]["mcp-session-id"] - - # Session 1: mock stream that raises ECONNRESET. - broken_stream = Object.new - broken_stream.define_singleton_method(:write) { |_data| raise Errno::ECONNRESET } - broken_stream.define_singleton_method(:close) {} - - get_request1 = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id1 }, - ) - response1 = @transport.handle_request(get_request1) - response1[2].call(broken_stream) if response1[2].is_a?(Proc) - - # Session 2: healthy stream. - healthy_stream = StringIO.new - get_request2 = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id2 }, - ) - response2 = @transport.handle_request(get_request2) - response2[2].call(healthy_stream) if response2[2].is_a?(Proc) - - # Give the streams time to set up. - sleep(0.1) - - # Broadcast notification - should not abort despite ECONNRESET from session 1. - sent_count = @transport.send_notification("test", { message: "hello" }, **{}) - - # Session 2 should have received the notification. - assert_equal 1, sent_count - - healthy_stream.rewind - output = healthy_stream.read - assert_includes output, '"method":"test"' - - # Session 1 should have been cleaned up. - assert_not @transport.instance_variable_get(:@sessions).key?(session_id1) - - # Session 2 should still exist. - assert @transport.instance_variable_get(:@sessions).key?(session_id2) - end - - test "send_notification to a session writes outside the mutex" do - session_id = initialize_test_session - writes = install_mutex_probe_stream(session_id) - - result = @transport.send_notification("test", { message: "hi" }, session_id: session_id) - - assert result - assert_equal 1, writes[:total] - assert_equal 0, writes[:under_mutex], "notification write must not hold @mutex" - end - - test "send_notification broadcast writes outside the mutex" do - session_id1 = initialize_test_session(id: "1") - session_id2 = initialize_test_session(id: "2") - writes1 = install_mutex_probe_stream(session_id1) - writes2 = install_mutex_probe_stream(session_id2) - - sent_count = @transport.send_notification("broadcast", { message: "hi" }, **{}) - - assert_equal 2, sent_count - assert_equal 0, writes1[:under_mutex], "broadcast write must not hold @mutex" - assert_equal 0, writes2[:under_mutex], "broadcast write must not hold @mutex" - end - - test "send_keepalive_ping writes outside the mutex" do - session_id = initialize_test_session - writes = install_mutex_probe_stream(session_id) - - @transport.send(:send_keepalive_ping, session_id) - - assert_equal 1, writes[:total] - assert_equal 0, writes[:under_mutex], "keepalive write must not hold @mutex" - end - - test "send_request writes outside the mutex" do - session_id = initialize_test_session - writes = install_mutex_probe_stream(session_id) - - result_queue = Queue.new - thread = Thread.new do - result_queue.push(@transport.send_request("ping", nil, session_id: session_id)) - end - - # Wait until the request has been written to the probe stream. - Thread.pass until writes[:total].positive? - - request_id = @transport.instance_variable_get(:@pending_responses).keys.first - @transport.send(:handle_response, { jsonrpc: "2.0", id: request_id, result: {} }, session_id: session_id) - - result_queue.pop - thread.join - - assert_equal 1, writes[:total] - assert_equal 0, writes[:under_mutex], "server-to-client request write must not hold @mutex" - end - - test "send_keepalive_ping handles Errno::ECONNRESET gracefully" do - # Create and initialize a session. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Use a mock stream that raises Errno::ECONNRESET on write. - mock_stream = Object.new - mock_stream.define_singleton_method(:write) { |_data| raise Errno::ECONNRESET } - mock_stream.define_singleton_method(:close) {} - - # Connect with SSE using the mock stream. - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(mock_stream) if response[2].is_a?(Proc) - - # Give the stream time to set up. - sleep(0.1) - - # send_keepalive_ping is private; re-raises to exit the keepalive loop. - # Errno::ECONNRESET should be caught by the rescue clause (which reports - # the exception) before being re-raised. Verify that exception_reporter - # is called — this fails if ECONNRESET is not in the rescue list. - reported_errors = [] - original_reporter = MCP.configuration.exception_reporter - MCP.configuration.exception_reporter = ->(error, context) { reported_errors << [error, context] } - - begin - assert_raises(Errno::ECONNRESET) do - @transport.send(:send_keepalive_ping, session_id) - end - - assert_equal(1, reported_errors.size) - assert_instance_of(Errno::ECONNRESET, reported_errors.first[0]) - assert_equal("Stream closed", reported_errors.first[1][:error]) - ensure - MCP.configuration.exception_reporter = original_reporter - end - end - test "responds with 405 for unsupported methods" do request = create_rack_request( "PUT", @@ -1546,61 +567,10 @@ module MCP response = @transport.handle_request(request) assert_equal 405, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Method not allowed", body["error"]["message"] - end - - test "POST request without Content-Type returns 415" do - request = create_rack_request_without_accept( - "POST", - "/", - { "HTTP_ACCEPT" => "application/json, text/event-stream" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 415, response[0] - - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Unsupported Media Type: Content-Type must be application/json", body["error"]["message"] - end - - test "POST request with wrong Content-Type returns 415" do - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "text/plain", - "HTTP_ACCEPT" => "application/json, text/event-stream", - }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 415, response[0] - end - - test "POST request with Content-Type including charset succeeds" do - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json; charset=utf-8", - "HTTP_ACCEPT" => "application/json, text/event-stream", - }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] + assert_equal "Method not allowed", body["error"] end test "POST request without Accept header returns 406" do @@ -1608,16 +578,16 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) assert_equal 406, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) assert_equal "Not Acceptable: Accept header must include application/json and text/event-stream", - body["error"]["message"] + body["error"] end test "POST request with Accept header missing text/event-stream returns 406" do @@ -1628,7 +598,7 @@ module MCP "CONTENT_TYPE" => "application/json", "HTTP_ACCEPT" => "application/json", }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) @@ -1636,7 +606,7 @@ module MCP body = JSON.parse(response[2][0]) assert_equal "Not Acceptable: Accept header must include application/json and text/event-stream", - body["error"]["message"] + body["error"] end test "POST request with Accept header missing application/json returns 406" do @@ -1647,7 +617,7 @@ module MCP "CONTENT_TYPE" => "application/json", "HTTP_ACCEPT" => "text/event-stream", }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) @@ -1655,7 +625,7 @@ module MCP body = JSON.parse(response[2][0]) assert_equal "Not Acceptable: Accept header must include application/json and text/event-stream", - body["error"]["message"] + body["error"] end test "POST request with valid Accept header succeeds" do @@ -1666,7 +636,7 @@ module MCP "CONTENT_TYPE" => "application/json", "HTTP_ACCEPT" => "application/json, text/event-stream", }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) @@ -1681,76 +651,22 @@ module MCP "CONTENT_TYPE" => "application/json", "HTTP_ACCEPT" => "application/json;q=0.9, text/event-stream;q=0.8", }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) response = @transport.handle_request(request) assert_equal 200, response[0] end - test "POST request with Accept: */* succeeds" do - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "*/*", - }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "POST request with mixed-case Accept header succeeds" do - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "Application/JSON, Text/Event-Stream", - }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "GET request with upper-case Accept header succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request_without_accept( - "GET", - "/", - { - "HTTP_ACCEPT" => "TEXT/EVENT-STREAM", - "HTTP_MCP_SESSION_ID" => session_id, - }, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - end - test "GET request without Accept header returns 406" do init_request = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] request = create_rack_request_without_accept( "GET", @@ -1762,10 +678,7 @@ module MCP assert_equal 406, response[0] body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - assert_equal "Not Acceptable: Accept header must include text/event-stream", body["error"]["message"] + assert_equal "Not Acceptable: Accept header must include text/event-stream", body["error"] end test "GET request with Accept header missing text/event-stream returns 406" do @@ -1773,10 +686,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] request = create_rack_request_without_accept( "GET", @@ -1791,7 +704,7 @@ module MCP assert_equal 406, response[0] body = JSON.parse(response[2][0]) - assert_equal "Not Acceptable: Accept header must include text/event-stream", body["error"]["message"] + assert_equal "Not Acceptable: Accept header must include text/event-stream", body["error"] end test "GET request with valid Accept header succeeds" do @@ -1799,10 +712,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "123" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] request = create_rack_request( "GET", @@ -1815,438 +728,7 @@ module MCP response = @transport.handle_request(request) assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - end - - test "GET request with Accept: */* succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request_without_accept( - "GET", - "/", - { - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_ACCEPT" => "*/*", - }, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - end - - test "POST initialize request ignores MCP-Protocol-Version header among legacy versions" do - # Per SEP-2575 header-primary routing, stable-only header values stay on the legacy path - # where `initialize` treats the body `params.protocolVersion` as authoritative. - # An unknown header value routes to the modern path (see the test below), and under - # the dual-era 2026-07-28 header a sessionless `initialize` stays legacy as well. - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_PROTOCOL_VERSION" => "2024-11-05", - }, - { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "POST initialize request with a non-legacy MCP-Protocol-Version header is rejected as modern traffic" do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_PROTOCOL_VERSION" => "1900-01-01", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32022, body.dig("error", "code")) - assert_equal "1900-01-01", body.dig("error", "data", "requested") - end - - test "POST initialize request negotiates body protocolVersion when header is an older supported version" do - older_version = "2025-06-18" - assert_includes Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, older_version - refute_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, older_version - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_PROTOCOL_VERSION" => older_version, - }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - # The body's requested version drives negotiation (not the older header); - # the default modern request is counter-offered the latest handshake version. - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, body["result"]["protocolVersion"] - end - - test "POST initialize request negotiates body protocolVersion when header is a newer supported version" do - older_version = "2025-06-18" - assert_includes Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, older_version - refute_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, older_version - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_PROTOCOL_VERSION" => Configuration::LATEST_STABLE_PROTOCOL_VERSION, - }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params(protocolVersion: older_version), - }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - assert_equal older_version, body["result"]["protocolVersion"] - end - - test "POST request with unsupported MCP-Protocol-Version returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01", - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) - - # Per SEP-2575 header-primary routing, a non-legacy version is modern traffic and - # receives `-32022` with the supported list instead of the legacy `-32600` message. - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_equal(-32022, body["error"]["code"]) - assert_equal "1999-01-01", body.dig("error", "data", "requested") - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("error", "data", "supported") - end - - test "POST request with malformed MCP-Protocol-Version returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "not-a-version", - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - - body = JSON.parse(response[2][0]) - assert_equal(-32022, body["error"]["code"]) - assert_equal "not-a-version", body.dig("error", "data", "requested") - end - - test "POST request with supported MCP-Protocol-Version succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => Configuration::LATEST_STABLE_PROTOCOL_VERSION, - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "POST request with the 2026-07-28 MCP-Protocol-Version header succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params(protocolVersion: "2026-07-28") }.to_json, - ) - init_response = @transport.handle_request(init_request) - # The handshake never negotiates a modern version (SEP-2575 era model); - # the session proceeds on the counter-offered 2025-11-25. - assert_equal "2025-11-25", JSON.parse(init_response[2][0])["result"]["protocolVersion"] - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28", - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "POST request without MCP-Protocol-Version header succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "missing MCP-Protocol-Version header falls back to default for validation" do - # The constant is frozen, so swap it out instead of stubbing `include?` on it. - original_versions = MCP::Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS - MCP::Configuration.send(:remove_const, :SUPPORTED_STABLE_PROTOCOL_VERSIONS) - MCP::Configuration.const_set(:SUPPORTED_STABLE_PROTOCOL_VERSIONS, [].freeze) - - request = Rack::Request.new( - "REQUEST_METHOD" => "POST", - "PATH_INFO" => "/", - "rack.input" => StringIO.new(""), - ) - - response = @transport.send(:validate_protocol_version_header, request) - assert_equal(400, response[0]) - - body = JSON.parse(response[2][0]) - assert_includes(body["error"]["message"], MCP::Configuration::DEFAULT_NEGOTIATED_PROTOCOL_VERSION) - ensure - MCP::Configuration.send(:remove_const, :SUPPORTED_STABLE_PROTOCOL_VERSIONS) - MCP::Configuration.const_set(:SUPPORTED_STABLE_PROTOCOL_VERSIONS, original_versions) - end - - test "POST request with empty MCP-Protocol-Version header returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "", - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - - body = JSON.parse(response[2][0]) - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - end - - test "POST request with array body and unsupported MCP-Protocol-Version returns 400" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01", - }, - [{ jsonrpc: "2.0", method: "tools/list", id: "list" }].to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - - body = JSON.parse(response[2][0]) - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, body["error"]["code"] - end - - test "GET request with a non-legacy MCP-Protocol-Version returns 405" do - # Per SEP-2575 header-primary routing, a non-legacy version is modern traffic, - # and the modern lifecycle removed the GET listening stream. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "GET", - "/", - { - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01", - }, - ) - - response = @transport.handle_request(request) - assert_equal 405, response[0] - end - - test "GET request without MCP-Protocol-Version header succeeds" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - end - - test "DELETE request with a non-legacy MCP-Protocol-Version returns 405" do - # Per SEP-2575 header-primary routing, a non-legacy version is modern traffic, - # and the modern lifecycle has no DELETE (there is no session to terminate). - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "DELETE", - "/", - { - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01", - }, - ) - - response = @transport.handle_request(request) - assert_equal 405, response[0] - end - - test "DELETE request with a non-legacy MCP-Protocol-Version returns 405 in stateless mode" do - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01" }, - ) - - response = stateless_transport.handle_request(request) - assert_equal 405, response[0] - end - - test "DELETE request with an unknown session and a non-legacy MCP-Protocol-Version returns 405" do - # Header-primary routing (SEP-2575) decides the era before any session validation. - request = create_rack_request( - "DELETE", - "/", - { - "HTTP_MCP_SESSION_ID" => "unknown-session-id", - "HTTP_MCP_PROTOCOL_VERSION" => "1999-01-01", - }, - ) - - response = @transport.handle_request(request) - assert_equal 405, response[0] + assert_equal "text/event-stream", response[1]["Content-Type"] end test "stateless mode allows requests without session IDs, responding with no session ID" do @@ -2256,10 +738,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = stateless_transport.handle_request(init_request) - assert_nil init_response[1]["mcp-session-id"] + assert_nil init_response[1]["Mcp-Session-Id"] end test "stateless mode responds without any session ID when session ID is present" do @@ -2279,7 +761,7 @@ module MCP assert_equal 200, response[0] assert_equal( { - "content-type" => "application/json", + "Content-Type" => "application/json", }, response[1], ) @@ -2301,10 +783,10 @@ module MCP ) response = stateless_transport.handle_request(get_request) assert_equal 405, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "Method not allowed", body["error"]["message"] + assert_equal "Method not allowed", body["error"] end test "stateless mode silently responds with success to session DELETE when session ID is not present" do @@ -2317,7 +799,7 @@ module MCP ) response = stateless_transport.handle_request(delete_request) assert_equal 200, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) assert body["success"] @@ -2333,106 +815,24 @@ module MCP ) response = stateless_transport.handle_request(delete_request) assert_equal 200, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) assert body["success"] end test "stateless mode does not support server-sent events" do - # Notifications have no stream to ride in stateless mode; the transport reports non-delivery - # instead of raising so per-request session notify_* helpers degrade gracefully (SEP-2567). stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - result = stateless_transport.send_notification( - "test_notification", - { message: "Hello" }, - session_id: "some_session_id", - ) - - refute result - end - - test "stateless mode does not leak client info onto the shared server" do - # Each stateless POST runs against an ephemeral per-request session (SEP-2567); concurrent requests - # must never observe another client's identity through the shared Server instance. - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { roots: {} }, - clientInfo: { name: "client-a", version: "1.0" }, - }, - }.to_json, - ) - response = stateless_transport.handle_request(request) - - assert_equal 200, response[0] - assert_nil @server.client_capabilities - assert_nil @server.instance_variable_get(:@client) - end - - test "stateless mode allows repeated initialize requests" do - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - 2.times do |i| - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: i + 1, - params: initialize_params(clientInfo: { name: "client-#{i}", version: "1.0" }), - }.to_json, + e = assert_raises(RuntimeError) do + stateless_transport.send_notification( + "test_notification", + { message: "Hello" }, + session_id: "some_session_id", ) - response = stateless_transport.handle_request(request) - - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - assert body.key?("result"), "initialize ##{i + 1} should succeed, got #{body.inspect}" - refute response[1].key?("mcp-session-id") end - end - test "stateless mode skips progress notifications without raising" do - reported = [] - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(exception, _context) { reported << exception } - - server = Server.new(name: "stateless_progress_test", configuration: configuration) - server.define_tool(name: "progress_tool") do |server_context:| - server_context.report_progress(50, total: 100) - Tool::Response.new([{ type: "text", text: "ok" }]) - end - stateless_transport = StreamableHTTPTransport.new(server, stateless: true) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "progress_tool", arguments: {}, _meta: { progressToken: "tok" } }, - }.to_json, - ) - response = stateless_transport.handle_request(request) - - assert_equal 200, response[0] - body = JSON.parse(response[2][0]) - assert_equal "ok", body.dig("result", "content", 0, "text") - assert_empty reported + assert_equal("Stateless mode does not support notifications", e.message) end test "stateless mode responds with 202 when client sends a notification/initialized request" do @@ -2447,475 +847,18 @@ module MCP response = stateless_transport.handle_request(request) assert_equal 202, response[0] - assert_equal({}, response[1]) + assert_empty(response[1]) body = response[2][0] assert_nil(body) end - test "POST request returns SSE response even with GET SSE connected" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect with GET SSE - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - sleep(0.1) - - # POST request should return SSE, not 202 - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - - post_io = StringIO.new - response[2].call(post_io) - body = JSON.parse(post_io.string.match(/^data: (.+)$/)[1]) - assert_equal "456", body["id"] - end - - test "JSON response mode returns application/json for POST requests" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - - body = JSON.parse(response[2][0]) - assert_equal("1", body["id"]) - ensure - transport.close - end - - test "JSON response mode accepts application/json only in Accept header" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "application/json", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - ensure - transport.close - end - - test "JSON response mode returns 406 when Accept header is missing" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - request = create_rack_request_without_accept( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(406, response[0]) - ensure - transport.close - end - - test "JSON response mode accepts wildcard Accept header" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - request = create_rack_request_without_accept( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "*/*", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - ensure - transport.close - end - - test "JSON response mode drops notifications during tool execution" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - server.define_tool(name: "log_tool") do |server_context:| - server_context.notify_log_message(data: "should be dropped", level: "info") - Tool::Response.new([{ type: "text", text: "ok" }]) - end - server.server_context = server - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "call-1", - method: "tools/call", - params: { name: "log_tool", arguments: {} }, - }.to_json, - ) - - response = transport.handle_request(tool_request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - - body = JSON.parse(response[2][0]) - assert_equal("call-1", body["id"]) - refute_includes(response[2][0], "should be dropped") - ensure - transport.close - end - - test "JSON response mode drops notifications even with GET SSE connected" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - server.define_tool(name: "log_tool") do |server_context:| - server_context.notify_log_message(data: "should not leak", level: "info") - Tool::Response.new([{ type: "text", text: "ok" }]) - end - server.server_context = server - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - get_response = transport.handle_request(get_request) - get_response[2].call(io) if get_response[2].is_a?(Proc) - sleep(0.1) - - # Call tool that sends a notification. - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "call-1", - method: "tools/call", - params: { name: "log_tool", arguments: {} }, - }.to_json, - ) - - response = transport.handle_request(tool_request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - - # Notification should NOT leak to GET SSE stream. - io.rewind - refute_includes(io.read, "should not leak") - ensure - transport.close - end - - test "JSON response mode raises on send_request (sampling)" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - error = assert_raises(RuntimeError) do - transport.send_request("sampling/createMessage", { messages: [] }, session_id: "s1") - end - - assert_equal("JSON response mode does not support server-to-client requests.", error.message) - ensure - transport.close - end - - test "JSON response mode raises on send_request (roots/list)" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - error = assert_raises(RuntimeError) do - transport.send_request("roots/list", nil, session_id: "s1") - end - - assert_equal("JSON response mode does not support server-to-client requests.", error.message) - ensure - transport.close - end - - test "JSON response mode raises on send_request (elicitation/create)" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - error = assert_raises(RuntimeError) do - transport.send_request( - "elicitation/create", - { mode: "form", message: "test", requestedSchema: {} }, - session_id: "s1", - ) - end - - assert_equal("JSON response mode does not support server-to-client requests.", error.message) - ensure - transport.close - end - - test "JSON response mode allows broadcast notifications via GET SSE" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - server.server_context = server - - server.define_tool(name: "notify_tool") do |server_context:| - server_context.notify_tools_list_changed - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - get_response = transport.handle_request(get_request) - get_response[2].call(io) if get_response[2].is_a?(Proc) - sleep(0.1) - - # Call tool that triggers a broadcast notification. - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "call-1", - method: "tools/call", - params: { name: "notify_tool", arguments: {} }, - }.to_json, - ) - - response = transport.handle_request(tool_request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - - # Broadcast notification should arrive on GET SSE stream. - io.rewind - assert_includes(io.read, "notifications/tools/list_changed") - ensure - transport.close - end - - test "JSON response mode with stateless returns application/json without session ID" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, stateless: true, enable_json_response: true) - server.transport = transport - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - assert_nil(response[1]["mcp-session-id"]) - - body = JSON.parse(response[2][0]) - assert_equal("1", body["id"]) - ensure - transport.close - end - - test "JSON response mode with stateless returns 405 on GET" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, stateless: true, enable_json_response: true) - server.transport = transport - - request = create_rack_request("GET", "/", {}) - - response = transport.handle_request(request) - assert_equal(405, response[0]) - ensure - transport.close - end - - test "JSON response mode delivers session-scoped standalone notifications via GET SSE" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - server.server_context = server - - server.define_tool(name: "touch_tool") do |server_context:| - server_context.notify_resources_updated(uri: "file:///example.txt") - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - get_response = transport.handle_request(get_request) - get_response[2].call(io) if get_response[2].is_a?(Proc) - sleep(0.1) - - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "call-1", - method: "tools/call", - params: { name: "touch_tool", arguments: {} }, - }.to_json, - ) - - response = transport.handle_request(tool_request) - assert_equal(200, response[0]) - assert_equal("application/json", response[1]["content-type"]) - - io.rewind - assert_includes(io.read, "notifications/resources/updated") - ensure - transport.close - end - test "handle post request with a standard error" do request = create_rack_request( "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "4567", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "4567" }.to_json, ) @transport.define_singleton_method(:extract_session_id) do |_request| @@ -2924,1088 +867,10 @@ module MCP response = @transport.handle_request(request) assert_equal 500, response[0] - assert_equal({ "content-type" => "application/json" }, response[1]) + assert_equal({ "Content-Type" => "application/json" }, response[1]) body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_nil body["id"] - assert_equal JsonRpcHandler::ErrorCode::INTERNAL_ERROR, body["error"]["code"] - assert_equal "Internal server error", body["error"]["message"] - end - - test "send_request raises error in stateless mode" do - stateless_transport = StreamableHTTPTransport.new(@server, stateless: true) - - error = assert_raises(RuntimeError) do - stateless_transport.send_request("sampling/createMessage", { "messages" => [] }) - end - - assert_equal("Stateless mode does not support server-to-client requests.", error.message) - end - - test "send_request refuses to run at all in the modern lifecycle" do - # SEP-2575 removes server-initiated requests, so a modern handler reaching for elicitation or sampling - # is told why rather than being sent down a path that fails on an unrelated session lookup. - modern_session = ServerSession.new(server: @server, transport: @transport, session_id: "modern-1", era: :modern) - - error = assert_raises(RuntimeError) do - @transport.send_request("elicitation/create", { message: "hi" }, session_id: "modern-1", server_session: modern_session) - end - - assert_equal("Server-initiated requests are not available in the modern lifecycle (SEP-2575).", error.message) - end - - test "send_request raises error when session_id is not provided" do - error = assert_raises(RuntimeError) do - @transport.send_request("sampling/createMessage", { "messages" => [] }) - end - - assert_equal("session_id is required for server-to-client requests.", error.message) - end - - test "send_request raises error when session is not found" do - error = assert_raises(RuntimeError) do - @transport.send_request("sampling/createMessage", { "messages" => [] }, session_id: "nonexistent") - end - - assert_equal("Session not found: nonexistent.", error.message) - end - - test "send_request raises error when no active SSE streams" do - # Create session but do NOT connect SSE. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - error = assert_raises(RuntimeError) do - @transport.send_request("sampling/createMessage", { "messages" => [] }, session_id: session_id) - end - - assert_equal("No active stream for sampling/createMessage request.", error.message) - end - - test "send_request sends via SSE and waits for response" do - # Create session. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) # Give the stream time to set up. - - # Send request in background. - result_queue = Queue.new - Thread.new do - result = @transport.send_request( - "sampling/createMessage", - { messages: [{ role: "user", content: { type: "text", text: "Hello" } }], maxTokens: 100 }, - session_id: session_id, - ) - result_queue.push(result) - end - - sleep(0.1) # Wait for the request to be sent. - - # Verify request was sent to stream. - io.rewind - output = io.read - assert_includes output, "sampling/createMessage" - - # Parse the sent request to get its ID. - data_lines = output.lines.select { |line| line.start_with?("data: ") } - request_data = JSON.parse(data_lines.first.sub("data: ", "")) - request_id = request_data["id"] - - # Simulate client response. - client_response = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: request_id, - result: { role: "assistant", content: { type: "text", text: "Hi there" } }, - }.to_json, - ) - @transport.handle_request(client_response) - - # Get result. - result = result_queue.pop - assert_equal "assistant", result[:role] - assert_equal "Hi there", result[:content][:text] - end - - test "send_request times out when the client never answers" do - # The spec asks implementations to bound every sent request so an unanswered one cannot - # exhaust the sender's resources. - transport = StreamableHTTPTransport.new(@server, server_to_client_request_timeout: 0.05) - session_id = open_sse_session(transport) - - error = assert_raises(MCP::Server::RequestTimeoutError) do - transport.send_request("sampling/createMessage", { messages: [] }, session_id: session_id) - end - - assert_equal 0.05, error.timeout - assert_includes error.message, "sampling/createMessage" - - # Left uncaught in a handler, the originating request is answered with a timeout code rather than - # a generic internal error, so the peer that failed to answer can tell the two apart. - assert_equal(-32001, error.error_code) - ensure - transport.close - end - - test "send_request timeout is overridable per request" do - transport = StreamableHTTPTransport.new(@server, server_to_client_request_timeout: 60) - session_id = open_sse_session(transport) - - error = assert_raises(MCP::Server::RequestTimeoutError) do - transport.send_request("ping", nil, session_id: session_id, timeout: 0.05) - end - - assert_equal 0.05, error.timeout - ensure - transport.close - end - - test "send_request tells the peer it gave up when the timeout fires" do - # These requests only happen on 2025-11-25 and earlier connections, whose spec asks the sender - # to issue a cancellation notification for the request it stops waiting on. - transport = StreamableHTTPTransport.new(@server, server_to_client_request_timeout: 0.05) - io = StringIO.new - session_id = open_sse_session(transport, io: io) - session = transport.instance_variable_get(:@sessions)[session_id][:server_session] - - assert_raises(MCP::Server::RequestTimeoutError) do - transport.send_request("ping", nil, session_id: session_id, server_session: session) - end - - events = io.string.lines.grep(/\Adata: /).map { |line| JSON.parse(line.sub("data: ", "")) } - cancellation = events.find { |event| event["method"] == "notifications/cancelled" } - refute_nil cancellation, "expected the peer to be told the request was abandoned" - assert_match(/Timed out after 0.05 seconds/, cancellation.dig("params", "reason")) - ensure - transport.close - end - - test "send_request returns the response when it arrives before the timeout" do - transport = StreamableHTTPTransport.new(@server, server_to_client_request_timeout: 30) - io = StringIO.new - session_id = open_sse_session(transport, io: io) - - result_queue = Queue.new - Thread.new do - result_queue.push(transport.send_request("ping", nil, session_id: session_id)) - end - wait_until { io.string.include?("ping") } - - request_id = JSON.parse(io.string.lines.grep(/\Adata: /).first.sub("data: ", ""))["id"] - transport.handle_request(create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", id: request_id, result: { ok: true } }.to_json, - )) - - assert_equal({ ok: true }, result_queue.pop) - ensure - transport.close - end - - test "server_to_client_request_timeout rejects a non-positive value" do - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, server_to_client_request_timeout: 0) } - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, server_to_client_request_timeout: -1) } - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, server_to_client_request_timeout: nil) } - end - - test "send_request with related_request_id rides the originating POST stream, not the GET stream" do - # Per SEP-2260, server-to-client requests associated with a client request are delivered on - # that request's POST SSE response stream rather than the standalone GET stream. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - get_io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(get_io) if response[2].is_a?(Proc) - sleep(0.1) - - # Register an in-flight POST request stream for "req-1". - post_io = StringIO.new - @transport.instance_variable_get(:@sessions)[session_id][:post_request_streams] = { "req-1" => post_io } - - result_queue = Queue.new - Thread.new do - result = @transport.send_request( - "roots/list", - nil, - session_id: session_id, - related_request_id: "req-1", - ) - result_queue.push(result) - end - - sleep(0.1) - - post_io.rewind - post_output = post_io.read - assert_includes post_output, "roots/list" - - get_io.rewind - refute_includes get_io.read, "roots/list" - - # Respond so the background send_request completes. - data_lines = post_output.lines.select { |line| line.start_with?("data: ") } - request_id = JSON.parse(data_lines.first.sub("data: ", ""))["id"] - client_response = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", id: request_id, result: { roots: [] } }.to_json, - ) - @transport.handle_request(client_response) - - assert_equal({ roots: [] }, result_queue.pop) - end - - test "send_request ignores response from wrong session" do - # Create two sessions. - init_a = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init-a", params: initialize_params }.to_json, - ) - resp_a = @transport.handle_request(init_a) - session_a = resp_a[1]["mcp-session-id"] - - init_b = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init-b", params: initialize_params }.to_json, - ) - resp_b = @transport.handle_request(init_b) - session_b = resp_b[1]["mcp-session-id"] - - # Connect SSE for session A. - io_a = StringIO.new - get_a = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session_a }) - response_a = @transport.handle_request(get_a) - response_a[2].call(io_a) if response_a[2].is_a?(Proc) - - sleep(0.1) # Give the stream time to set up. - - # Send sampling request targeting session A. - result_queue = Queue.new - Thread.new do - result = @transport.send_request( - "sampling/createMessage", - { messages: [{ role: "user", content: { type: "text", text: "Hello" } }], maxTokens: 100 }, - session_id: session_a, - ) - result_queue.push(result) - end - - sleep(0.1) # Wait for the request to be sent. - - # Get the request ID from session A's stream. - io_a.rewind - data_lines = io_a.read.lines.select { |line| line.start_with?("data: ") } - request_data = JSON.parse(data_lines.first.sub("data: ", "")) - request_id = request_data["id"] - - # Session B tries to respond (cross-session injection attempt). - cross_session_response = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_b }, - { jsonrpc: "2.0", id: request_id, result: { role: "assistant", content: { type: "text", text: "injected" } } }.to_json, - ) - @transport.handle_request(cross_session_response) - - # The request should still be pending (not resolved by wrong session). - assert_empty(result_queue, "Response from wrong session should be ignored") - - # Now send the correct response from session A. - correct_response = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_a }, - { jsonrpc: "2.0", id: request_id, result: { role: "assistant", content: { type: "text", text: "correct" } } }.to_json, - ) - @transport.handle_request(correct_response) - - result = result_queue.pop - assert_equal "correct", result[:content][:text] - end - - test "send_request with parent_cancellation unblocks with MCP::CancelledError when cancelled" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - io = StringIO.new - get_request = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session_id }) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) - - cancellation = MCP::Cancellation.new(request_id: "parent-1") - server_session = @transport.instance_variable_get(:@sessions)[session_id][:server_session] - - result_queue = Queue.new - Thread.new do - @transport.send_request( - "sampling/createMessage", - { messages: [] }, - session_id: session_id, - parent_cancellation: cancellation, - server_session: server_session, - ) - rescue => e - result_queue.push(e) - end - - sleep(0.1) - cancellation.cancel(reason: "parent cancelled") - - error = result_queue.pop - assert_kind_of MCP::CancelledError, error - end - - test "send_request deregisters on_cancel hook after completion so late parent cancel is a no-op" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - io = StringIO.new - get_request = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session_id }) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) - - cancellation = MCP::Cancellation.new(request_id: "parent-x") - server_session = @transport.instance_variable_get(:@sessions)[session_id][:server_session] - - result_queue = Queue.new - Thread.new do - result = @transport.send_request( - "sampling/createMessage", - { messages: [] }, - session_id: session_id, - parent_cancellation: cancellation, - server_session: server_session, - ) - result_queue.push(result) - end - - sleep(0.1) - - io.rewind - data_lines = io.read.lines.select { |line| line.start_with?("data: ") } - request_data = JSON.parse(data_lines.first.sub("data: ", "")) - nested_request_id = request_data["id"] - - # Client responds successfully; send_request completes normally. - client_response = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", id: nested_request_id, result: { role: "assistant", content: { type: "text", text: "ok" } } }.to_json, - ) - @transport.handle_request(client_response) - - result = result_queue.pop - assert_equal "ok", result[:content][:text] - - # Snapshot what was written to the SSE stream before late cancel. - io.rewind - before_cancel = io.read - - # Parent is cancelled after the nested request already completed. The hook must - # have been deregistered, so no `notifications/cancelled` should go to the peer - # for the already-completed nested request. - cancellation.cancel(reason: "late") - - sleep(0.05) # Give any stray callback time to fire (none should). - - io.rewind - after_cancel = io.read - - refute_includes after_cancel.sub(before_cancel, ""), "notifications/cancelled" - end - - test "cancel_pending_request is no-op when a real response is already queued (race)" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - io = StringIO.new - get_request = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session_id }) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) - - result_queue = Queue.new - Thread.new do - result = @transport.send_request( - "sampling/createMessage", - { messages: [] }, - session_id: session_id, - ) - result_queue.push(result) - end - - sleep(0.1) - - io.rewind - data_lines = io.read.lines.select { |line| line.start_with?("data: ") } - request_data = JSON.parse(data_lines.first.sub("data: ", "")) - request_id = request_data["id"] - - # Client responded first. - client_response = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", id: request_id, result: { role: "assistant", content: { type: "text", text: "ok" } } }.to_json, - ) - @transport.handle_request(client_response) - - # Cancel arrives after the response was already enqueued. Must not clobber the result. - @transport.cancel_pending_request(request_id, reason: "late cancel") - - result = result_queue.pop - assert_equal "ok", result[:content][:text] - end - - test "refuses a POST reusing an in-flight request id and keeps the original stream" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - server.transport = transport - - gate = Queue.new - server.define_tool(name: "victim_tool") do |server_context:| - server_context.report_progress(1, message: "first-frame") - gate.pop - server_context.report_progress(2, message: "second-frame") - Tool::Response.new([{ type: "text", text: "done" }]) - end - - session_id, server_session = start_session(transport) - - victim = transport.handle_request(colliding_tool_call(session_id, "req-1")) - victim_stream = TestStream.new - victim_thread = Thread.new { victim[2].call(victim_stream) } - sleep(0.01) until server_session.lookup_in_flight("req-1") - - attacker = transport.handle_request(colliding_tool_call(session_id, "req-1")) - - assert_equal 409, attacker[0] - assert_equal( - JsonRpcHandler::ErrorCode::INVALID_REQUEST, - JSON.parse(attacker[2][0]).dig("error", "code"), - ) - - gate << :go - victim_thread.join - - # The registration survived the refusal, so the frame emitted after it still reaches - # the request that asked for it. - assert_includes victim_stream.string, "first-frame" - assert_includes victim_stream.string, "second-frame" - end - - test "a finishing request leaves a stream another request registered under the same id" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - server.transport = transport - - gate = Queue.new - server.define_tool(name: "victim_tool") do |server_context:| - gate.pop - Tool::Response.new([{ type: "text", text: "done" }]) - end - - session_id, server_session = start_session(transport) - - victim = transport.handle_request(colliding_tool_call(session_id, "req-1")) - victim_stream = TestStream.new - victim_thread = Thread.new { victim[2].call(victim_stream) } - sleep(0.01) until server_session.lookup_in_flight("req-1") - - # Stand in for a stream that won the registration in a race the pre-dispatch refusal normally prevents. - # Finishing the other request must not unregister it. - foreign_stream = TestStream.new - sessions = transport.instance_variable_get(:@sessions) - sessions[session_id][:post_request_streams]["req-1"] = foreign_stream - - gate << :go - victim_thread.join - - assert_same foreign_stream, sessions[session_id][:post_request_streams]["req-1"] - end - - test "a broken request-scoped stream drops only itself, even when it is not the registered one" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - server.transport = transport - - session_id, = start_session(transport) - sessions = transport.instance_variable_get(:@sessions) - registered = TestStream.new - sessions[session_id][:post_request_streams] = { "req-1" => registered } - - transport.send(:drop_broken_stream, session_id, TestStream.new, "req-1") - - assert sessions.key?(session_id), "a request-scoped failure must not tear down the session" - assert_same registered, sessions[session_id][:post_request_streams]["req-1"] - end - - test "allows a request id to be reused once the earlier request has finished" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - server.transport = transport - - server.define_tool(name: "victim_tool") do |server_context:| - Tool::Response.new([{ type: "text", text: "done" }]) - end - - session_id, = start_session(transport) - - 2.times do - response = transport.handle_request(colliding_tool_call(session_id, "req-1")) - - assert_equal 200, response[0] - stream = TestStream.new - response[2].call(stream) - assert_includes stream.string, "done" - end - end - - test "JSON response mode returns accepted when cancellation suppresses response" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server, enable_json_response: true) - server.transport = transport - - server.define_tool(name: "slow_tool") do |server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - - Tool::Response.new([{ type: "text", text: "done" }]) - end - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "init", - params: initialize_params, - }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - server_session = transport.instance_variable_get(:@sessions)[session_id][:server_session] - - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "call-1", - method: "tools/call", - params: { name: "slow_tool", arguments: {} }, - }.to_json, - ) - - response_queue = Queue.new - request_thread = Thread.new { response_queue.push(transport.handle_request(tool_request)) } - sleep(0.01) until server_session.lookup_in_flight("call-1") - - cancel_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - method: MCP::Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "call-1", reason: "user cancelled" }, - }.to_json, - ) - - cancel_response = transport.handle_request(cancel_request) - assert_equal(202, cancel_response[0]) - - response = response_queue.pop - assert_equal(202, response[0]) - assert_empty(response[1]) - assert_empty(response[2]) - ensure - request_thread.kill if request_thread.alive? - transport.close - end - - test "send_request raises on error response from client" do - # Create session. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) # Give the stream time to set up. - - error_queue = Queue.new - Thread.new do - @transport.send_request("sampling/createMessage", { messages: [] }, session_id: session_id) - rescue => e - error_queue.push(e) - end - - sleep(0.1) # Wait for the request to be sent. - - # Get request ID from stream. - io.rewind - data_lines = io.read.lines.select { |line| line.start_with?("data: ") } - request_data = JSON.parse(data_lines.first.sub("data: ", "")) - request_id = request_data["id"] - - # Send error response. - error_response = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: request_id, - error: { code: -1, message: "User rejected" }, - }.to_json, - ) - @transport.handle_request(error_response) - - error = error_queue.pop - assert_kind_of StandardError, error - assert_equal("Client returned an error for sampling/createMessage request (code: -1): User rejected", error.message) - end - - test "send_request unblocks when session is cleaned up" do - # Create session. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect SSE. - io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = @transport.handle_request(get_request) - response[2].call(io) if response[2].is_a?(Proc) - - sleep(0.1) # Give the stream time to set up. - - error_queue = Queue.new - Thread.new do - @transport.send_request("sampling/createMessage", { messages: [] }, session_id: session_id) - rescue => e - error_queue.push(e) - end - - sleep(0.1) # Wait for the request to be sent. - - # Delete the session to trigger cleanup (simulates client disconnect). - delete_request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - @transport.handle_request(delete_request) - - error = error_queue.pop - assert_kind_of RuntimeError, error - assert_equal("SSE session closed while waiting for sampling/createMessage response.", error.message) - end - - test "send_request sends via POST response stream even with GET SSE connected" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Connect GET SSE. - get_io = StringIO.new - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - get_response = @transport.handle_request(get_request) - get_response[2].call(get_io) if get_response[2].is_a?(Proc) - sleep(0.1) - - # Set up sampling capability for the session. - @transport.instance_variable_get(:@sessions)[session_id][:server_session] - .store_client_info(client: { name: "test" }, capabilities: { sampling: {} }) - - # Define a tool that calls create_sampling_message. - sampling_tool = MCP::Tool.define( - name: "sampling_tool", - input_schema: { properties: { prompt: { type: "string" } }, required: ["prompt"] }, - ) do |prompt:, server_context:| - result = server_context.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: prompt } }], - max_tokens: 100, - ) - MCP::Tool::Response.new([{ type: "text", text: result[:content][:text] }]) - end - @server.tools[sampling_tool.name_value] = sampling_tool - - # Send tools/call via POST (GET SSE is connected). - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "tool-1", - method: "tools/call", - params: { name: "sampling_tool", arguments: { prompt: "Hello" } }, - }.to_json, - ) - - post_stream = TestStream.new - result_queue = Queue.new - Thread.new do - response = @transport.handle_request(tool_request) - response[2].call(post_stream) - result_queue.push(:done) - end - - sleep(0.2) - - # Sampling request should be in POST response stream, not GET SSE. - output = post_stream.string - data_lines = output.lines.select { |line| line.start_with?("data: ") } - sampling_request = JSON.parse(data_lines.first.sub("data: ", "")) - assert_equal "sampling/createMessage", sampling_request["method"] - - # GET SSE should NOT have the sampling request. - get_io.rewind - refute_includes get_io.read, "sampling/createMessage" - - # Simulate client sending sampling result via POST. - client_response = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: sampling_request["id"], - result: { role: "assistant", content: { type: "text", text: "Hi from LLM" } }, - }.to_json, - ) - @transport.handle_request(client_response) - - result_queue.pop - - tool_response_lines = post_stream.string.lines.select { |line| line.start_with?("data: ") } - tool_response = JSON.parse(tool_response_lines.last.sub("data: ", "")) - assert_equal "tool-1", tool_response["id"] - assert_includes tool_response["result"]["content"].first["text"], "Hi from LLM" - end - - test "send_request sends via POST response stream when no GET SSE stream" do - # Create session without connecting GET SSE. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Set up sampling capability for the session. - @transport.instance_variable_get(:@sessions)[session_id][:server_session] - .store_client_info(client: { name: "test" }, capabilities: { sampling: {} }) - - # Define a tool that calls create_sampling_message. - sampling_tool = MCP::Tool.define( - name: "sampling_tool", - input_schema: { properties: { prompt: { type: "string" } }, required: ["prompt"] }, - ) do |prompt:, server_context:| - result = server_context.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: prompt } }], - max_tokens: 100, - ) - MCP::Tool::Response.new([{ type: "text", text: result[:content][:text] }]) - end - @server.tools[sampling_tool.name_value] = sampling_tool - - # Send tools/call via POST (no GET SSE stream). - tool_request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "tool-1", - method: "tools/call", - params: { name: "sampling_tool", arguments: { prompt: "Hello" } }, - }.to_json, - ) - - # Process in background since handle_request blocks until tool completes. - post_stream = TestStream.new - result_queue = Queue.new - Thread.new do - response = @transport.handle_request(tool_request) - response[2].call(post_stream) - result_queue.push(:done) - end - - sleep(0.2) # Wait for the tool to start and send sampling request. - - # Read the sampling request from the POST response stream. - output = post_stream.string - data_lines = output.lines.select { |line| line.start_with?("data: ") } - sampling_request = JSON.parse(data_lines.first.sub("data: ", "")) - assert_equal "sampling/createMessage", sampling_request["method"] - - # Simulate client sending sampling result via POST. - client_response = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: sampling_request["id"], - result: { role: "assistant", content: { type: "text", text: "Hi from LLM" } }, - }.to_json, - ) - @transport.handle_request(client_response) - - result_queue.pop # Wait for tool to complete. - - # Verify the tool result was written to the POST response stream. - tool_response_lines = post_stream.string.lines.select { |line| line.start_with?("data: ") } - tool_response = JSON.parse(tool_response_lines.last.sub("data: ", "")) - assert_equal "tool-1", tool_response["id"] - assert_includes tool_response["result"]["content"].first["text"], "Hi from LLM" - end - - test "send_notification uses POST response stream when no GET SSE stream" do - # Create session without connecting GET SSE. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Define a tool that sends a notification during execution. - notification_sent = Queue.new - slow_tool = MCP::Tool.define( - name: "slow_tool", - ) do |server_context:| - server_context.notify_log_message(data: "test log", level: "info") - notification_sent.push(true) - MCP::Tool::Response.new([{ type: "text", text: "done" }]) - end - @server.tools[slow_tool.name_value] = slow_tool - - # Configure logging so notifications are sent. - @transport.instance_variable_get(:@sessions)[session_id][:server_session] - .configure_logging(MCP::LoggingMessageNotification.new(level: "debug")) - - # Send tools/call via POST (no GET SSE stream). - post_stream = TestStream.new - result_queue = Queue.new - Thread.new do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "tool-1", - method: "tools/call", - params: { name: "slow_tool", arguments: {} }, - }.to_json, - ) - response = @transport.handle_request(request) - response[2].call(post_stream) - result_queue.push(:done) - end - - notification_sent.pop # Wait for tool to send notification. - result_queue.pop - - # Verify notification was written to the POST response stream. - assert_includes post_stream.string, "notifications/message" - assert_includes post_stream.string, "test log" - end - - test "progress notification uses POST response stream when no GET SSE stream" do - # Create session without connecting GET SSE. - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Define a tool that reports progress during execution. - progress_reported = Queue.new - progress_tool = MCP::Tool.define( - name: "progress_tool", - ) do |server_context:| - server_context.report_progress(50, total: 100, message: "halfway") - progress_reported.push(true) - MCP::Tool::Response.new([{ type: "text", text: "done" }]) - end - @server.tools[progress_tool.name_value] = progress_tool - - # Send tools/call via POST (no GET SSE stream) with a progress token. - post_stream = TestStream.new - result_queue = Queue.new - Thread.new do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { - jsonrpc: "2.0", - id: "tool-1", - method: "tools/call", - params: { name: "progress_tool", arguments: {}, _meta: { progressToken: "token-1" } }, - }.to_json, - ) - response = @transport.handle_request(request) - response[2].call(post_stream) - result_queue.push(:done) - end - - progress_reported.pop - result_queue.pop - - # Verify progress notification was written to the POST response stream. - assert_includes post_stream.string, "notifications/progress" - assert_includes post_stream.string, "token-1" + assert_equal "Internal server error", body["error"] end test "POST notifications/initialized returns 202 with no body" do @@ -4014,10 +879,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] notif_request = create_rack_request( "POST", @@ -4031,462 +896,8 @@ module MCP response = @transport.handle_request(notif_request) assert_equal 202, response[0] - assert_equal({}, response[1]) - assert_equal([], response[2]) - end - - test "expired session returns 404 on GET request" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - # Create a session - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "123", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - assert(session_id) - - # Session should now be expired (timeout is 0) - sleep(0.01) - - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = transport.handle_request(get_request) - assert_equal(404, response[0]) - - body = JSON.parse(response[2][0]) - assert_equal("Session not found", body["error"]["message"]) - ensure - transport.close - end - - test "expired session returns 404 on POST request" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - # Create a session - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Session should now be expired (timeout is 0) - sleep(0.01) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(404, response[0]) - - body = JSON.parse(response[2][0]) - assert_equal("Session not found", body["error"]["message"]) - ensure - transport.close - end - - test "session_idle_timeout: nil disables session expiry" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: nil) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Make a request - session should still be valid - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - ensure - transport.close - end - - test "session within timeout period remains valid" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 3600) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - response = transport.handle_request(request) - assert_equal(200, response[0]) - ensure - transport.close - end - - test "session activity resets the idle timeout" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.5) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Send requests every 0.2s to keep the session alive. - # Total elapsed time (~0.6s) exceeds timeout (0.5s), but each request - # resets the idle timer so the session remains valid. - 3.times do - sleep(0.2) - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - response = transport.handle_request(request) - assert_equal(200, response[0]) - end - ensure - transport.close - end - - test "reaper thread cleans up expired sessions" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - assert(session_id) - - # Wait for session to expire - sleep(0.02) - - # Manually trigger reaper since the background thread runs on 60s interval - transport.send(:reap_expired_sessions) - - # Session should have been reaped - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - ) - response = transport.handle_request(get_request) - assert_equal(404, response[0]) - ensure - transport.close - end - - test "reaper thread cleans up expired sessions and POST returns 404" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Wait for the session to exceed the idle timeout (0.01s) - sleep(0.02) - transport.send(:reap_expired_sessions) - - # POST to a reaped session should also return 404 - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - response = transport.handle_request(request) - assert_equal(404, response[0]) - - body = JSON.parse(response[2][0]) - assert_equal("Session not found", body["error"]["message"]) - ensure - transport.close - end - - test "reap_expired_sessions closes stream outside mutex" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Replace the stream with one that verifies mutex is NOT held during close. - mutex = transport.instance_variable_get(:@mutex) - closed_outside_mutex = false - mock_stream = Object.new - mock_stream.define_singleton_method(:close) do - # If stream.close runs outside the mutex, try_lock succeeds. - if mutex.try_lock - closed_outside_mutex = true - mutex.unlock - end - end - transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] = mock_stream - - sleep(0.02) # Wait for session to expire. - - transport.send(:reap_expired_sessions) - - assert(closed_outside_mutex, "Stream should be closed outside the mutex") - assert_empty(transport.instance_variable_get(:@sessions)) - ensure - transport.close - end - - test "close stops the reaper thread" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 3600) - reaper_thread = transport.instance_variable_get(:@reaper_thread) - assert reaper_thread - assert reaper_thread.alive? - - transport.close - - sleep(0.01) - refute reaper_thread.alive? - assert_nil transport.instance_variable_get(:@reaper_thread) - end - - test "reaper thread is not started when session_idle_timeout is nil" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: nil) - assert_nil(transport.instance_variable_get(:@reaper_thread)) - ensure - transport.close - end - - test "applies a finite session_idle_timeout by default and starts the reaper" do - # Secure default: stateful mode expires idle sessions out of the box. - transport = StreamableHTTPTransport.new(@server) - assert_equal( - StreamableHTTPTransport::DEFAULT_SESSION_IDLE_TIMEOUT, - transport.instance_variable_get(:@session_idle_timeout), - ) - assert(transport.instance_variable_get(:@reaper_thread).alive?) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - # A freshly created session is well within the timeout, so normal use is unaffected. - session_id = transport.handle_request(init_request)[1]["mcp-session-id"] - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - - assert_equal(200, transport.handle_request(request)[0]) - ensure - transport.close - end - - test "session_idle_timeout: nil opts out of expiry" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: nil) - assert_nil(transport.instance_variable_get(:@session_idle_timeout)) - assert_nil(transport.instance_variable_get(:@reaper_thread)) - ensure - transport.close - end - - test "stateless mode keeps no idle timeout despite the secure default" do - transport = StreamableHTTPTransport.new(@server, stateless: true) - assert_nil(transport.instance_variable_get(:@session_idle_timeout)) - assert_nil(transport.instance_variable_get(:@reaper_thread)) - ensure - transport.close - end - - test "rejects new initialize with 503 once max_sessions is reached" do - transport = StreamableHTTPTransport.new(@server, max_sessions: 2) - - 2.times do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - assert_equal(200, transport.handle_request(request)[0]) - end - - overflow = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - response = transport.handle_request(overflow) - - assert_equal(503, response[0]) - assert_equal(2, transport.instance_variable_get(:@sessions).size) - ensure - transport.close - end - - test "at the cap, reclaims an already-expired session before rejecting" do - # A very short idle timeout so the first session is expired by the time the cap would otherwise reject - # a new initialize; the expired slot is reclaimed. - transport = StreamableHTTPTransport.new(@server, max_sessions: 1, session_idle_timeout: 0.01) - init = lambda do - transport.handle_request(create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - )) - end - - assert_equal(200, init.call[0]) - sleep(0.05) # let the first session's idle timer expire - second = init.call - - # The expired session was reclaimed in-line, so the second initialize succeeds (200) rather than - # being rejected with 503, and the store stays at the cap. - assert_equal(200, second[0]) - assert_equal(1, transport.instance_variable_get(:@sessions).size) - ensure - transport.close - end - - test "max_sessions: nil opts out of the session cap" do - transport = StreamableHTTPTransport.new(@server, max_sessions: nil) - assert_nil(transport.instance_variable_get(:@max_sessions)) - ensure - transport.close - end - - test "raises ArgumentError for an invalid max_sessions" do - [0, -1, 1.5, "10"].each do |invalid| - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, max_sessions: invalid) } - end - end - - test "raises ArgumentError when session_idle_timeout is zero" do - error = assert_raises(ArgumentError) do - StreamableHTTPTransport.new(@server, session_idle_timeout: 0) - end - assert_equal("session_idle_timeout must be a positive number.", error.message) - end - - test "raises ArgumentError when session_idle_timeout is negative" do - error = assert_raises(ArgumentError) do - StreamableHTTPTransport.new(@server, session_idle_timeout: -1) - end - assert_equal("session_idle_timeout must be a positive number.", error.message) - end - - test "raises ArgumentError when session_idle_timeout is used with stateless mode" do - error = assert_raises(ArgumentError) do - StreamableHTTPTransport.new(@server, stateless: true, session_idle_timeout: 3600) - end - assert_equal("session_idle_timeout is not supported in stateless mode.", error.message) - end - - test "expired session does not receive targeted notification" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Wait for the session to exceed the idle timeout (0.01s) - sleep(0.02) - - result = transport.send_notification("test/notify", { message: "hello" }, session_id: session_id) - refute(result) - ensure - transport.close - end - - test "expired session is skipped during broadcast notification" do - transport = StreamableHTTPTransport.new(@server, session_idle_timeout: 0.01) - - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - init_response = transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - # Attach a mock stream to the session - stream = StringIO.new - transport.instance_variable_get(:@sessions)[session_id][:get_sse_stream] = stream - - # Wait for the session to exceed the idle timeout (0.01s) - sleep(0.02) - - sent_count = transport.send_notification("test/notify", { message: "hello" }, **{}) - assert_equal(0, sent_count) - ensure - transport.close + assert_empty(response[1]) + assert_empty(response[2]) end test "handles POST request with body including JSON-RPC response object and returns with no body" do @@ -4494,10 +905,10 @@ module MCP "POST", "/", { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, + { jsonrpc: "2.0", method: "initialize", id: "init" }.to_json, ) init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] + session_id = init_response[1]["Mcp-Session-Id"] request = create_rack_request( "POST", @@ -4511,1916 +922,12 @@ module MCP response = @transport.handle_request(request) assert_equal 202, response[0] - assert_equal({}, response[1]) - assert_equal([], response[2]) - end - - test "POST response without session ID returns 400" do - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", result: "success", id: "123" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Missing session ID", body["error"]["message"] - end - - test "POST response with invalid session ID returns 404" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - @transport.handle_request(init_request) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => "invalid-session-id", - }, - { jsonrpc: "2.0", result: "success", id: "123" }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 404, response[0] - body = JSON.parse(response[2][0]) - assert_equal "Session not found", body["error"]["message"] - end - - test "handle_regular_request returns 404 for unknown session_id" do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => "nonexistent-session", - }, - { jsonrpc: "2.0", method: "ping", id: "456" }.to_json, - ) - response = @transport.handle_request(request) - assert_equal(404, response[0]) - body = JSON.parse(response[2][0]) - assert_equal("Session not found", body["error"]["message"]) - end - - test "session-scoped log notification is sent only to the originating session" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - transport = StreamableHTTPTransport.new(server) - - server.define_tool(name: "log_tool") do |server_context:| - server_context.notify_log_message(data: "secret", level: "info") - Tool::Response.new([{ type: "text", text: "ok" }]) - end - server.server_context = server - - # Create two sessions. - init1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "1", - params: initialize_params(clientInfo: { name: "a", version: "1.0" }), - }.to_json, - ) - session1 = transport.handle_request(init1)[1]["mcp-session-id"] - - init2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "2", - params: initialize_params(clientInfo: { name: "b", version: "1.0" }), - }.to_json, - ) - session2 = transport.handle_request(init2)[1]["mcp-session-id"] - - # Connect SSE for both sessions. - io1 = StringIO.new - get1 = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session1 }) - response1 = transport.handle_request(get1) - response1[2].call(io1) if response1[2].is_a?(Proc) - - io2 = StringIO.new - get2 = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session2 }) - response2 = transport.handle_request(get2) - response2[2].call(io2) if response2[2].is_a?(Proc) - - sleep(0.1) - - # Call tool from session 1. - tool_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session1 }, - { - jsonrpc: "2.0", - method: "tools/call", - id: "call-1", - params: { name: "log_tool", arguments: {} }, - }.to_json, - ) - tool_response = transport.handle_request(tool_request) - post_io = StringIO.new - tool_response[2].call(post_io) - - # Session 1's POST response stream should contain the log notification. - assert_includes post_io.string, "secret" - - # GET SSE streams should NOT receive the log notification. - io1.rewind - refute_includes io1.read, "secret" - io2.rewind - refute_includes io2.read, "secret" - end - - test "session-scoped progress notification is sent only to the originating session" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - - server.define_tool(name: "progress_tool") do |server_context:| - server_context.report_progress(50, total: 100, message: "halfway") - Tool::Response.new([{ type: "text", text: "ok" }]) - end - server.server_context = server - - # Create two sessions. - init1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "1", - params: initialize_params(clientInfo: { name: "a", version: "1.0" }), - }.to_json, - ) - session1 = transport.handle_request(init1)[1]["mcp-session-id"] - - init2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "2", - params: initialize_params(clientInfo: { name: "b", version: "1.0" }), - }.to_json, - ) - session2 = transport.handle_request(init2)[1]["mcp-session-id"] - - # Connect SSE for both sessions. - io1 = StringIO.new - get1 = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session1 }) - response1 = transport.handle_request(get1) - response1[2].call(io1) if response1[2].is_a?(Proc) - - io2 = StringIO.new - get2 = create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session2 }) - response2 = transport.handle_request(get2) - response2[2].call(io2) if response2[2].is_a?(Proc) - - sleep(0.1) - - # Call tool from session 1 with a progress token. - tool_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session1 }, - { - jsonrpc: "2.0", - method: "tools/call", - id: "call-1", - params: { - name: "progress_tool", - arguments: {}, - _meta: { progressToken: "token-1" }, - }, - }.to_json, - ) - tool_response = transport.handle_request(tool_request) - post_io = StringIO.new - tool_response[2].call(post_io) - - # Session 1's POST response stream should contain the progress notification. - assert_includes post_io.string, "halfway" - - # GET SSE streams should NOT receive the progress notification. - io1.rewind - refute_includes io1.read, "halfway" - io2.rewind - refute_includes io2.read, "halfway" - end - - test "each session stores its own client info independently" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - - # Initialize session 1 with client "alpha". - init1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "1", - params: initialize_params(clientInfo: { name: "alpha", version: "1.0" }), - }.to_json, - ) - session1 = transport.handle_request(init1)[1]["mcp-session-id"] - - # Initialize session 2 with client "beta". - init2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "2", - params: initialize_params(clientInfo: { name: "beta", version: "2.0" }), - }.to_json, - ) - session2 = transport.handle_request(init2)[1]["mcp-session-id"] - - # Each session should have its own client info. - sessions = transport.instance_variable_get(:@sessions) - assert_equal({ name: "alpha", version: "1.0" }, sessions[session1][:server_session].client) - assert_equal({ name: "beta", version: "2.0" }, sessions[session2][:server_session].client) - end - - test "each session stores its own logging level independently" do - server = Server.new(name: "test", tools: [], prompts: [], resources: []) - transport = StreamableHTTPTransport.new(server) - - # Initialize two sessions. - init1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "1", - params: initialize_params(clientInfo: { name: "a", version: "1.0" }), - }.to_json, - ) - session1 = transport.handle_request(init1)[1]["mcp-session-id"] - - init2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { - jsonrpc: "2.0", - method: "initialize", - id: "2", - params: initialize_params(clientInfo: { name: "b", version: "1.0" }), - }.to_json, - ) - session2 = transport.handle_request(init2)[1]["mcp-session-id"] - - # Session 1 sets log level to "error". - set_level1 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session1 }, - { - jsonrpc: "2.0", - method: "logging/setLevel", - id: "3", - params: { level: "error" }, - }.to_json, - ) - response1 = transport.handle_request(set_level1) - response1[2].call(StringIO.new) - - # Session 2 sets log level to "debug". - set_level2 = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session2 }, - { - jsonrpc: "2.0", - method: "logging/setLevel", - id: "4", - params: { level: "debug" }, - }.to_json, - ) - response2 = transport.handle_request(set_level2) - response2[2].call(StringIO.new) - - # Session 1 (error level) should not notify for "info", but should for "error". - session1_logging = transport.instance_variable_get(:@sessions)[session1][:server_session].logging_message_notification - refute session1_logging.should_notify?("info") - assert session1_logging.should_notify?("error") - - # Session 2 (debug level) should notify for both "info" and "debug". - session2_logging = transport.instance_variable_get(:@sessions)[session2][:server_session].logging_message_notification - assert session2_logging.should_notify?("info") - assert session2_logging.should_notify?("debug") - end - - test "call(env) works as a Rack app for POST requests" do - env = { - "REQUEST_METHOD" => "POST", - "PATH_INFO" => "/", - "rack.input" => StringIO.new({ jsonrpc: "2.0", method: "initialize", id: "init-1", params: initialize_params }.to_json), - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "application/json, text/event-stream", - } - - response = @transport.call(env) - assert_equal 200, response[0] - assert_equal "application/json", response[1]["content-type"] - - body = JSON.parse(response[2][0]) - assert_equal "2.0", body["jsonrpc"] - assert_equal "init-1", body["id"] - end - - test "call(env) returns 405 for unsupported HTTP methods" do - env = { - "REQUEST_METHOD" => "PUT", - "PATH_INFO" => "/", - "rack.input" => StringIO.new(""), - } - - response = @transport.call(env) - assert_equal 405, response[0] - end - - test "call(env) handles GET SSE stream request" do - init_env = { - "REQUEST_METHOD" => "POST", - "PATH_INFO" => "/", - "rack.input" => StringIO.new({ jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json), - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "application/json, text/event-stream", - } - init_response = @transport.call(init_env) - session_id = init_response[1]["mcp-session-id"] - - get_env = { - "REQUEST_METHOD" => "GET", - "PATH_INFO" => "/", - "rack.input" => StringIO.new(""), - "HTTP_ACCEPT" => "text/event-stream", - "HTTP_MCP_SESSION_ID" => session_id, - } - - response = @transport.call(get_env) - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - assert response[2].is_a?(Proc) - end - - test "call(env) handles DELETE session request" do - init_env = { - "REQUEST_METHOD" => "POST", - "PATH_INFO" => "/", - "rack.input" => StringIO.new({ jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json), - "CONTENT_TYPE" => "application/json", - "HTTP_ACCEPT" => "application/json, text/event-stream", - } - init_response = @transport.call(init_env) - session_id = init_response[1]["mcp-session-id"] - - delete_env = { - "REQUEST_METHOD" => "DELETE", - "PATH_INFO" => "/", - "rack.input" => StringIO.new(""), - "HTTP_MCP_SESSION_ID" => session_id, - } - - response = @transport.call(delete_env) - assert_equal 200, response[0] - - body = JSON.parse(response[2][0]) - assert body["success"] - end - - test "SSE response headers are not frozen so Rack middleware can modify them" do - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init-frozen", params: initialize_params }.to_json, - ) - init_response = @transport.handle_request(init_request) - session_id = init_response[1]["mcp-session-id"] - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "tools/list", id: "sse-headers-1" }.to_json, - ) - - status, headers, = @transport.handle_request(request) - assert_equal 200, status - assert_equal "text/event-stream", headers["content-type"] - refute headers.frozen?, "SSE response headers should not be frozen" - end - - test "rejects a request body over max_request_bytes with 413 without reading it all" do - transport = StreamableHTTPTransport.new(@server, max_request_bytes: 1024) - oversized = { jsonrpc: "2.0", method: "initialize", id: "1", params: { x: "A" * 4096 } }.to_json - - # Content-Length present: rejected before reading. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "CONTENT_LENGTH" => oversized.bytesize.to_s }, - oversized, - ) - response = transport.handle_request(request) - - assert_equal 413, response[0] - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, JSON.parse(response[2][0]).dig("error", "code") - end - - test "rejects an oversized body even when Content-Length is absent" do - transport = StreamableHTTPTransport.new(@server, max_request_bytes: 1024) - oversized = { jsonrpc: "2.0", method: "initialize", id: "1", params: { x: "A" * 4096 } }.to_json - - # No CONTENT_LENGTH: the bounded read must still catch it. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - oversized, - ) - response = transport.handle_request(request) - - assert_equal 413, response[0] - end - - test "accepts a request body at the max_request_bytes boundary" do - transport = StreamableHTTPTransport.new(@server, max_request_bytes: 4096) - body = { jsonrpc: "2.0", method: "initialize", id: "1", params: initialize_params }.to_json - assert_operator body.bytesize, :<=, 4096 - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - body, - ) - response = transport.handle_request(request) - - assert_equal 200, response[0] - end - - test "rejects deeply nested JSON beyond the nesting cap as a parse error" do - depth = StreamableHTTPTransport::MAX_JSON_NESTING + 5 - nested = ("[" * depth) + ("]" * depth) - body = %({"jsonrpc":"2.0","method":"initialize","id":"1","params":{"deep":#{nested}}}) - - request = create_rack_request("POST", "/", { "CONTENT_TYPE" => "application/json" }, body) - response = @transport.handle_request(request) - - assert_equal 400, response[0] - assert_equal JsonRpcHandler::ErrorCode::PARSE_ERROR, JSON.parse(response[2][0]).dig("error", "code") - end - - test "raises ArgumentError for an invalid max_request_bytes" do - [nil, 0, -1, 1.5, "1024"].each do |invalid| - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, max_request_bytes: invalid) } - end - end - - test "handle_request returns 403 for POST when Origin is not in allowed_origins" do - transport = StreamableHTTPTransport.new(@server, allowed_origins: ["https://app.example.com"]) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ORIGIN" => "https://evil.example.com", - }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - status, headers, body = transport.handle_request(request) - assert_equal(403, status) - assert_equal("application/json", headers["content-type"]) - parsed = JSON.parse(body.first) - assert_equal(JsonRpcHandler::ErrorCode::INVALID_REQUEST, parsed["error"]["code"]) - assert_equal("Forbidden: Invalid Origin header", parsed["error"]["message"]) - ensure - transport&.close - end - - test "handle_request returns 403 for GET when Origin is not in allowed_origins" do - transport = StreamableHTTPTransport.new(@server, allowed_origins: ["https://app.example.com"]) - - request = create_rack_request( - "GET", - "/", - { "HTTP_ORIGIN" => "https://evil.example.com" }, - ) - - status, = transport.handle_request(request) - assert_equal(403, status) - ensure - transport&.close - end - - test "handle_request returns 403 for DELETE when Origin is not in allowed_origins" do - transport = StreamableHTTPTransport.new(@server, allowed_origins: ["https://app.example.com"]) - - request = create_rack_request( - "DELETE", - "/", - { - "HTTP_ORIGIN" => "https://evil.example.com", - "HTTP_MCP_SESSION_ID" => "any", - }, - ) - - status, = transport.handle_request(request) - assert_equal(403, status) - ensure - transport&.close - end - - test "handle_request allows POST when Origin is in allowed_origins" do - transport = StreamableHTTPTransport.new(@server, allowed_origins: ["https://app.example.com"]) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ORIGIN" => "https://app.example.com", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = transport.handle_request(request) - assert_equal(200, status) - ensure - transport&.close - end - - test "handle_request allows POST when Origin header is absent (e.g. non-browser client)" do - transport = StreamableHTTPTransport.new(@server, allowed_origins: ["https://app.example.com"]) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = transport.handle_request(request) - assert_equal(200, status) - ensure - transport&.close - end - - test "handle_request rejects a cross-origin request by default (secure-by-default)" do - # No allowed_origins configured: a browser cross-origin Origin is still rejected. - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_ORIGIN" => "https://anywhere.example.com", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = @transport.handle_request(request) - assert_equal 403, status - end - - test "handle_request allows a same-origin browser request" do - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => "localhost:3000", - "HTTP_ORIGIN" => "http://localhost:3000", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = @transport.handle_request(request) - assert_equal 200, status - end - - test "handle_request rejects a rebound Host by default" do - # DNS rebinding: a foreign Host re-pointed at the loopback server is rejected. - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => "evil.example.com", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, headers, body = @transport.handle_request(request) - assert_equal(403, status) - assert_equal("application/json", headers["content-type"]) - parsed = JSON.parse(body.first) - assert_equal(JsonRpcHandler::ErrorCode::INVALID_REQUEST, parsed["error"]["code"]) - assert_equal("Forbidden: Invalid Host header", parsed["error"]["message"]) - end - - test "handle_request allows loopback Host values by default" do - ["127.0.0.1:8080", "localhost:3000", "[::1]:8080"].each do |host| - transport = StreamableHTTPTransport.new(@server) - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => host, - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = transport.handle_request(request) - assert_equal(200, status, "expected #{host} to be allowed") - ensure - transport.close - end - end - - test "handle_request matches Host case-insensitively" do - # Host names are case-insensitive, so an upper-cased loopback Host is allowed. - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => "LOCALHOST:3000", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = @transport.handle_request(request) - assert_equal(200, status) - end - - test "handle_request allows a non-loopback Host listed in allowed_hosts" do - transport = StreamableHTTPTransport.new(@server, allowed_hosts: ["app.example.com"]) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => "app.example.com", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = transport.handle_request(request) - assert_equal(200, status) - ensure - transport.close - end - - test "handle_request matches a host:port entry in allowed_hosts exactly" do - transport = StreamableHTTPTransport.new(@server, allowed_hosts: ["app.example.com:8443"]) - - allowed = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_HOST" => "app.example.com:8443" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - rejected = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_HOST" => "app.example.com:9000" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - assert_equal(200, transport.handle_request(allowed).first) - assert_equal(403, transport.handle_request(rejected).first) - ensure - transport.close - end - - test "handle_request treats a default port as same-origin" do - # `Origin: http://localhost` (no port) is same-origin with `Host: localhost:80`. - [ - ["http://localhost", "localhost:80"], - ["https://localhost", "localhost:443"], - ].each do |origin, host| - transport = StreamableHTTPTransport.new(@server) - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_HOST" => host, "HTTP_ORIGIN" => origin }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - assert_equal(200, transport.handle_request(request).first, "expected #{origin} / #{host} to match") - ensure - transport.close - end - end - - test "handle_request rejects opaque and malformed Origins" do - ["null", "file:///etc/passwd", "http://localhost:3000/path"].each do |origin| - transport = StreamableHTTPTransport.new(@server) - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_HOST" => "localhost:3000", "HTTP_ORIGIN" => origin }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - assert_equal(403, transport.handle_request(request).first, "expected #{origin} to be rejected") - ensure - transport.close - end - end - - test "handle_request enforces Host validation on GET requests" do - request = create_rack_request( - "GET", - "/", - { "HTTP_HOST" => "evil.example.com" }, - ) - - status, = @transport.handle_request(request) - assert_equal(403, status) - end - - test "handle_request allows a request with no Host header" do - # Non-browser clients may omit Host; the rebinding vector always carries one. - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = @transport.handle_request(request) - assert_equal(200, status) - end - - test "handle_request skips DNS rebinding checks when protection is disabled" do - transport = StreamableHTTPTransport.new(@server, dns_rebinding_protection: false) - - request = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_HOST" => "evil.example.com", - "HTTP_ORIGIN" => "https://evil.example.com", - }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - - status, = transport.handle_request(request) - assert_equal(200, status) - ensure - transport.close - end - - test "rejects a POST to a session whose Origin differs from initialize with 403" do - # Both origins are allow-listed so they pass DNS rebinding protection; the rejection - # below comes from the per-session Origin-consistency gate, not from the rebinding check. - transport = StreamableHTTPTransport.new( - @server, - enable_json_response: true, - allowed_origins: ["https://app.example.com", "https://evil.example.com"], - ) - init = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_ORIGIN" => "https://app.example.com" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(init)[1]["mcp-session-id"] - - attacker = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_ORIGIN" => "https://evil.example.com", - }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - response = transport.handle_request(attacker) - - assert_equal(403, response[0]) - ensure - transport.close - end - - test "allows a POST with a matching Origin and one with no Origin" do - transport = StreamableHTTPTransport.new( - @server, - enable_json_response: true, - allowed_origins: ["https://app.example.com"], - ) - init = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_ORIGIN" => "https://app.example.com" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(init)[1]["mcp-session-id"] - - same_origin = create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_ORIGIN" => "https://app.example.com", - }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - - # A non-browser client that sends no Origin is not rejected by the built-in check. - no_origin = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "ping", id: "2" }.to_json, - ) - - assert_equal(200, transport.handle_request(same_origin)[0]) - assert_equal(200, transport.handle_request(no_origin)[0]) - ensure - transport.close - end - - test "a custom session_request_validator rejects and allows requests" do - allowed = { value: true } - validator = ->(_request, _session_id) { allowed[:value] } - transport = StreamableHTTPTransport.new(@server, enable_json_response: true, session_request_validator: validator) - init = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(init)[1]["mcp-session-id"] - - ping = lambda do - create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - end - - assert_equal(200, transport.handle_request(ping.call)[0]) - allowed[:value] = false - assert_equal(403, transport.handle_request(ping.call)[0]) - ensure - transport.close - end - - test "the validator also gates notification and response POSTs, not just regular requests" do - # A stolen session ID must not be able to POST `notifications/cancelled` (which would cancel a victim's in-flight request) - # or a client response by bypassing the ownership gate. `initialize` establishes the session and is exempt, - # so a single transport whose validator always rejects still initializes. - transport = StreamableHTTPTransport.new( - @server, - enable_json_response: true, - session_request_validator: ->(_request, _session_id) { false }, - ) - init = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(init)[1]["mcp-session-id"] - refute_nil(session_id) - - headers = { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id } - cancelled = create_rack_request( - "POST", - "/", - headers, - { jsonrpc: "2.0", method: "notifications/cancelled", params: { requestId: "1" } }.to_json, - ) - client_response = create_rack_request( - "POST", - "/", - headers, - { jsonrpc: "2.0", id: "1", result: {} }.to_json, - ) - - assert_equal(403, transport.handle_request(cancelled)[0]) - assert_equal(403, transport.handle_request(client_response)[0]) - ensure - transport.close - end - - test "session_request_validator receives the request and session id" do - seen = {} - validator = ->(request, session_id) { - seen[:origin] = request.env["HTTP_ORIGIN"] - seen[:session_id] = session_id - true - } - transport = StreamableHTTPTransport.new( - @server, - enable_json_response: true, - allowed_origins: ["https://app.example.com"], - session_request_validator: validator, - ) - init = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(init)[1]["mcp-session-id"] - - transport.handle_request(create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id, "HTTP_ORIGIN" => "https://app.example.com" }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - )) - - assert_equal(session_id, seen[:session_id]) - assert_equal("https://app.example.com", seen[:origin]) - ensure - transport.close - end - - test "session validation does not apply in stateless mode" do - rejecting = ->(_request, _session_id) { false } - transport = StreamableHTTPTransport.new(@server, stateless: true, enable_json_response: true, session_request_validator: rejecting) - - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "ping", id: "1" }.to_json, - ) - response = transport.handle_request(request) - - # Stateless mode keeps no sessions, so the validator is never consulted. - assert_equal(200, response[0]) - ensure - transport.close - end - - test "modern POST serves a single sessionless JSON exchange" do - @server.define_tool(name: "echo_tool") do - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - response = @transport.handle_request(modern_rack_request( - modern_body("tools/call", { name: "echo_tool", arguments: {} }), - headers: { "HTTP_MCP_METHOD" => "tools/call", "HTTP_MCP_NAME" => "echo_tool" }, - )) - - assert_equal 200, response[0] - refute response[1].key?("mcp-session-id") - body = JSON.parse(response[2][0]) - assert_equal "ok", body.dig("result", "content", 0, "text") - end - - test "modern POST with an unsupported header version returns 400 with -32022 and the supported list" do - response = @transport.handle_request(modern_rack_request( - modern_body("ping", {}, version: "2027-01-01"), - version: "2027-01-01", - )) - - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32022, body.dig("error", "code")) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("error", "data", "supported") - assert_equal "2027-01-01", body.dig("error", "data", "requested") - end - - test "modern POST with a header/body version mismatch returns 400 with -32020" do - # Header names the supported modern version; the body envelope claims another. - response = @transport.handle_request(modern_rack_request( - modern_body("ping", {}, version: "2027-01-01"), - )) - - assert_equal 400, response[0] - assert_equal(-32020, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern POST with an Mcp-Method header mismatch returns 400 with -32020" do - response = @transport.handle_request(modern_rack_request( - modern_body("ping", {}), - headers: { "HTTP_MCP_METHOD" => "tools/call" }, - )) - - assert_equal 400, response[0] - assert_equal(-32020, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern POST without the Mcp-Method header returns 400 with -32020" do - # The header is required on every modern POST; a missing required standard header is - # a validation failure, matching the TypeScript SDK's enforcement. - response = @transport.handle_request(modern_rack_request( - modern_body("ping", {}), - method_header: nil, - )) - - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32020, body.dig("error", "code")) - assert_includes body.dig("error", "message"), "Mcp-Method" - end - - test "modern POST without the Mcp-Name header on a name-bearing method returns 400 with -32020" do - response = @transport.handle_request(modern_rack_request( - modern_body("tools/call", { name: "some_tool", arguments: {} }), - name_header: nil, - )) - - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32020, body.dig("error", "code")) - assert_includes body.dig("error", "message"), "Mcp-Name" - end - - test "modern POST decodes the base64 Mcp-Name sentinel and enforces the match" do - # `Mcp-Name` mirrors `params.uri` for `resources/read`; a non-ASCII value arrives - # wrapped in the `=?base64?...?=` sentinel produced by `MCP::Client::HTTP`. - uri = "file:///日本語.txt" - encoded = "=?base64?#{[uri].pack("m0")}?=" - - matched = @transport.handle_request(modern_rack_request( - modern_body("resources/read", { uri: uri }), - headers: { "HTTP_MCP_NAME" => encoded }, - )) - mismatched = @transport.handle_request(modern_rack_request( - modern_body("resources/read", { uri: "file:///other.txt" }), - headers: { "HTTP_MCP_NAME" => encoded }, - )) - - assert_equal 200, matched[0] - assert_equal 400, mismatched[0] - assert_equal(-32020, JSON.parse(mismatched[2][0]).dig("error", "code")) - end - - test "modern POST rejects an Mcp-Session-Id header" do - response = @transport.handle_request(modern_rack_request( - modern_body("ping", {}), - headers: { "HTTP_MCP_SESSION_ID" => "some-session" }, - )) - - assert_equal 400, response[0] - assert_equal(-32600, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern GET and DELETE are not allowed" do - get_request = create_rack_request( - "GET", - "/", - { "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28" }, - ) - delete_request = create_rack_request( - "DELETE", - "/", - { "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28" }, - ) - - assert_equal 405, @transport.handle_request(get_request)[0] - assert_equal 405, @transport.handle_request(delete_request)[0] - end - - test "modern POST maps an unknown method to 404 with -32601" do - response = @transport.handle_request(modern_rack_request(modern_body("no/such_method", {}))) - - assert_equal 404, response[0] - assert_equal(-32601, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern POST requires the _meta envelope" do - response = @transport.handle_request(modern_rack_request( - { jsonrpc: "2.0", method: "tools/list", id: 1 }.to_json, - )) - - assert_equal 400, response[0] - assert_equal(-32602, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern POST rejects an envelope missing clientCapabilities with 400 and -32602" do - body = { - jsonrpc: "2.0", - method: "tools/list", - id: 1, - params: { _meta: { "io.modelcontextprotocol/protocolVersion": "2026-07-28" } }, - }.to_json - - response = @transport.handle_request(modern_rack_request(body)) - - assert_equal 400, response[0] - assert_equal(-32602, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "modern POST serves an envelope without the optional clientInfo" do - body = { - jsonrpc: "2.0", - method: "tools/list", - id: 1, - params: { - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientCapabilities": {}, - }, - }, - }.to_json - - response = @transport.handle_request(modern_rack_request(body)) - - assert_equal 200, response[0] - assert JSON.parse(response[2][0]).key?("result") - end - - test "modern POST answers removed lifecycle methods with 404 and -32601" do - MCP::Methods::MODERN_REMOVED_METHODS.each do |method| - response = @transport.handle_request(modern_rack_request(modern_body(method, {}))) - - assert_equal 404, response[0], "expected 404 for #{method}" - body = JSON.parse(response[2][0]) - assert_equal(-32601, body.dig("error", "code"), "expected -32601 for #{method}") - assert_equal 1, body["id"], "expected the request id to be preserved for #{method}" - end - end - - test "modern POST maps a missing client capability to 400 with -32021" do - @server.define_tool(name: "guarded_tool") do |server_context:| - server_context.require_client_capability!(:elicitation, :form) - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - response = @transport.handle_request(modern_rack_request( - modern_body("tools/call", { name: "guarded_tool", arguments: {} }), - headers: { "HTTP_MCP_NAME" => "guarded_tool" }, - )) - - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32021, body.dig("error", "code")) - assert_equal({ "elicitation" => { "form" => {} } }, body.dig("error", "data", "requiredCapabilities")) - end - - test "modern POST streams handler notifications ahead of the final response" do - @server.define_tool(name: "progress_tool") do |server_context:| - server_context.report_progress(50, total: 100) - Tool::Response.new([{ type: "text", text: "done" }]) - end - - body = { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "progress_tool", - arguments: {}, - _meta: { - progressToken: "tok-1", - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - }, - }, - }.to_json - - response = @transport.handle_request(modern_rack_request(body)) - - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - frames = response[2][0].split("\n\n").reject(&:empty?).map do |chunk| - JSON.parse(chunk.sub(/\Aevent: message\ndata: /, "")) - end - assert_equal "notifications/progress", frames.first["method"] - assert_equal "tok-1", frames.first.dig("params", "progressToken") - assert frames.last.key?("result"), "expected the final frame to carry the result" - assert_equal 1, frames.last["id"] - end - - test "modern POST bounds the buffered notifications per request" do - # The sink holds notifications in memory until the handler returns, so a handler - # emitting in proportion to client input must not grow one request without bound. - overflow = 5 - delivery_results = [] - @server.define_tool(name: "flood_tool") do |server_context:| - (StreamableHTTPTransport::MAX_MODERN_REQUEST_NOTIFICATIONS + overflow).times do |i| - delivery_results << server_context.notify_log_message(data: "message #{i}", level: "info") - end - Tool::Response.new([{ type: "text", text: "done" }]) - end - - body = { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "flood_tool", - arguments: {}, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - "io.modelcontextprotocol/logLevel": "info", - }, - }, - }.to_json - - response = @transport.handle_request(modern_rack_request(body)) - - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - frames = response[2][0].split("\n\n").reject(&:empty?) - assert_equal StreamableHTTPTransport::MAX_MODERN_REQUEST_NOTIFICATIONS + 1, frames.size - assert_equal overflow, delivery_results.count { |result| result == false } - end - - test "modern POST without handler notifications keeps the single JSON exchange" do - response = @transport.handle_request(modern_rack_request(modern_body("tools/list", {}))) - - assert_equal 200, response[0] - assert_equal "application/json", response[1]["content-type"] - end - - test "modern POST suppresses log notifications without the envelope logLevel" do - # SEP-2575: log delivery is authorized per request via the `_meta` logLevel; - # the server-wide level does not apply to modern requests. - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - @server.define_tool(name: "logging_tool") do |server_context:| - server_context.notify_log_message(data: "hi", level: "info") - Tool::Response.new([{ type: "text", text: "done" }]) - end - - response = @transport.handle_request(modern_rack_request( - modern_body("tools/call", { name: "logging_tool", arguments: {} }), - )) - - assert_equal 200, response[0] - assert_equal "application/json", response[1]["content-type"] - refute_includes response[2][0], "notifications/message" - end - - test "modern POST delivers log notifications when the envelope carries logLevel" do - @server.define_tool(name: "logging_tool") do |server_context:| - server_context.notify_log_message(data: "hi", level: "info") - Tool::Response.new([{ type: "text", text: "done" }]) - end - - body = { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "logging_tool", - arguments: {}, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - "io.modelcontextprotocol/logLevel": "info", - }, - }, - }.to_json - - response = @transport.handle_request(modern_rack_request(body)) - - assert_equal 200, response[0] - assert_equal "text/event-stream", response[1]["content-type"] - assert_includes response[2][0], "notifications/message" - end - - test "modern POST treats an unrecognized envelope logLevel as absent" do - # Matching the Python SDK, an unrecognized level reads as absent: - # delivery stays off instead of erroring on every log call. - reported = [] - configuration = MCP::Configuration.new(exception_reporter: ->(e, _ctx) { reported << e }) - server = Server.new(name: "log_level_test", configuration: configuration) - transport = StreamableHTTPTransport.new(server, dns_rebinding_protection: false) - server.define_tool(name: "logging_tool") do |server_context:| - server_context.notify_log_message(data: "hi", level: "info") - Tool::Response.new([{ type: "text", text: "done" }]) - end - - body = { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "logging_tool", - arguments: {}, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - "io.modelcontextprotocol/logLevel": "bogus", - }, - }, - }.to_json - - response = transport.handle_request(modern_rack_request(body)) - - assert_equal 200, response[0] - assert_equal "application/json", response[1]["content-type"] - refute_includes response[2][0], "notifications/message" - assert_empty reported - end - - test "modern POST serves server/discover carrying the envelope" do - response = @transport.handle_request(modern_rack_request(modern_body("server/discover", {}))) - - assert_equal 200, response[0] - refute response[1].key?("mcp-session-id") - body = JSON.parse(response[2][0]) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions") - end - - test "modern POST rejects an envelope-less server/discover with 400 and -32602" do - # The 2026-07-28 conformance requirements validate the `_meta` envelope on `server/discover` like - # on every other modern request (SEP-2575). - response = @transport.handle_request(modern_rack_request( - { jsonrpc: "2.0", method: "server/discover", id: 1 }.to_json, - )) - - assert_equal 400, response[0] - assert_equal(-32602, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "legacy POST rejects a modern envelope body without the modern header as -32020" do - # Without header-primary routing evidence, the body-level triple would silently fall through - # the legacy path via the header default. - session_id = initialize_test_session - - response = @transport.handle_request(create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - modern_body("ping", {}), - )) - - assert_equal 400, response[0] - assert_equal(-32020, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "sessionless POST initialize with the dual-era header stays legacy and is counter-offered" do - # The 2026-07-28 header alone cannot route the era: a sessionless `initialize` body is - # the legacy-distinctive handshake, so a client sending both connects over the legacy lifecycle - # and is counter-offered the latest handshake version (SEP-2575 era model). - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params(protocolVersion: "2026-07-28") }.to_json, - ) - - response = @transport.handle_request(request) - assert_equal 200, response[0] - refute_nil response[1]["mcp-session-id"] - assert_equal "2025-11-25", JSON.parse(response[2][0]).dig("result", "protocolVersion") - end - - test "session-bound POST with the dual-era header stays on the legacy path" do - # A deliberately lenient reading. The header names a version the handshake refused to - # negotiate, so it disagrees with the session; the session wins and the request is served - # at the negotiated revision, unstamped. Rejecting instead would read the spec's - # "invalid or unsupported MCP-Protocol-Version MUST be 400" as covering a version this - # server does in fact support (through the modern lifecycle), and would break a client - # over what is a SHOULD on its side: sending the negotiated version rather than its own. - session_id = initialize_test_session - - response = @transport.handle_request(create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28", - }, - { jsonrpc: "2.0", method: "tools/list", id: "list" }.to_json, - )) - - assert_equal 200, response[0] - - io = StringIO.new - response[2].call(io) - body = sse_events(io).first - - # No `resultType`: the header claim does not move the session onto the modern wire. - refute(body["result"].key?("resultType")) - end - - test "session-bound DELETE with the dual-era header terminates the legacy session" do - session_id = initialize_test_session - - response = @transport.handle_request(create_rack_request( - "DELETE", - "/", - { - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28", - }, - )) - - assert_equal 200, response[0] - end - - test "session-bound POST with the dual-era header carrying the modern envelope is rejected as -32600" do - # The session already negotiated the legacy lifecycle, and a connection can never change eras - # (mirroring the stdio era lock). - session_id = initialize_test_session - - response = @transport.handle_request(create_rack_request( - "POST", - "/", - { - "CONTENT_TYPE" => "application/json", - "HTTP_MCP_SESSION_ID" => session_id, - "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28", - }, - modern_body("ping", {}), - )) - - assert_equal 400, response[0] - body = JSON.parse(response[2][0]) - assert_equal(-32600, body.dig("error", "code")) - assert_includes body.dig("error", "message"), "legacy lifecycle" - end - - test "modern POST larger than max_request_bytes returns 413" do - transport = StreamableHTTPTransport.new(@server, max_request_bytes: 64) - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_PROTOCOL_VERSION" => "2026-07-28" }, - modern_body("ping", { filler: "A" * 200 }), - ) - - response = transport.handle_request(request) - assert_equal(413, response[0]) - ensure - transport.close - end - - test "subscriptions/listen opens an SSE stream and acknowledges the honored subset first" do - # `resourceSubscriptions` honoring requires the `resources.subscribe` capability flag, - # which the server defaults do not declare. - server = Server.new( - name: "listen_test", - capabilities: { tools: { listChanged: true }, resources: { listChanged: true, subscribe: true } }, - ) - transport = StreamableHTTPTransport.new(server) - - io = open_listen_stream( - id: "listen-1", - notifications: { toolsListChanged: true, resourceSubscriptions: ["file:///a.txt"] }, - transport: transport, - ) - - events = sse_events(io) - assert_equal(1, events.size) - ack = events[0] - assert_equal("notifications/subscriptions/acknowledged", ack["method"]) - assert_equal( - { "toolsListChanged" => true, "resourceSubscriptions" => ["file:///a.txt"] }, - ack.dig("params", "notifications"), - ) - assert_equal("listen-1", ack.dig("params", "_meta", "io.modelcontextprotocol/subscriptionId")) - ensure - transport.close - end - - test "SSE responses disable proxy buffering" do - # The spec asks servers to send `X-Accel-Buffering: no` on SSE streams so a reverse proxy - # delivers events as they are written; on a listen stream, buffering would also swallow - # the keepalive frames that detect a dropped peer. - listen = @transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-1", params: { notifications: { toolsListChanged: true } }), - )) - - session_id = initialize_test_session - get_stream = @transport.handle_request(create_rack_request("GET", "/", { "HTTP_MCP_SESSION_ID" => session_id })) - - assert_equal("no", listen[1]["x-accel-buffering"]) - assert_equal("no", get_stream[1]["x-accel-buffering"]) - end - - test "subscriptions/listen acknowledgement omits notification types the server does not support" do - server = Server.new(name: "listen_test", capabilities: { tools: { listChanged: true } }) - transport = StreamableHTTPTransport.new(server) - - io = open_listen_stream( - id: "listen-1", - notifications: { toolsListChanged: true, promptsListChanged: true, resourceSubscriptions: ["file:///a.txt"] }, - transport: transport, - ) - - ack = sse_events(io)[0] - assert_equal({ "toolsListChanged" => true }, ack.dig("params", "notifications")) - ensure - transport.close - end - - test "subscriptions/listen requires a notifications filter object" do - response = @transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-1", params: {}), - )) - - assert_equal 400, response[0] - assert_equal(-32602, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "subscriptions/listen requires the modern _meta envelope" do - response = @transport.handle_request(modern_rack_request( - { jsonrpc: "2.0", method: "subscriptions/listen", id: "listen-1", params: { notifications: {} } }.to_json, - )) - - assert_equal 400, response[0] - assert_equal(-32600, JSON.parse(response[2][0]).dig("error", "code")) - end - - test "subscriptions/listen delivers only opted-in notifications with the subscriptionId" do - io = open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - - @server.notify_tools_list_changed - # Not opted in: MUST NOT be delivered. - @server.notify_prompts_list_changed - - events = sse_events(io) - assert_equal 2, events.size - assert_equal "notifications/subscriptions/acknowledged", events[0]["method"] - assert_equal "notifications/tools/list_changed", events[1]["method"] - assert_equal "listen-1", events[1].dig("params", "_meta", "io.modelcontextprotocol/subscriptionId") - end - - test "subscriptions/listen delivers resource updates only for subscribed URIs" do - server = Server.new( - name: "listen_test", - capabilities: { resources: { listChanged: true, subscribe: true } }, - ) - transport = StreamableHTTPTransport.new(server) - - io = open_listen_stream( - id: "listen-1", - notifications: { resourceSubscriptions: ["file:///subscribed.txt"] }, - transport: transport, - ) - - # `**{}` keeps the params Hash positional on Ruby 2.7, matching the other `send_notification` tests. - transport.send_notification("notifications/resources/updated", { uri: "file:///subscribed.txt" }, **{}) - transport.send_notification("notifications/resources/updated", { uri: "file:///other.txt" }, **{}) - - events = sse_events(io) - assert_equal(2, events.size) - assert_equal("notifications/resources/updated", events[1]["method"]) - assert_equal("file:///subscribed.txt", events[1].dig("params", "uri")) - assert_equal("listen-1", events[1].dig("params", "_meta", "io.modelcontextprotocol/subscriptionId")) - ensure - transport.close - end - - test "notifications are delivered only after the listen acknowledgement" do - # Inject an entry in the registered-but-not-yet-acknowledged state: the window between - # the registry insert and the acknowledgement write, which happens outside the lock. - io = StringIO.new - @transport.instance_variable_get(:@listen_subscriptions)["listen-1"] = { - stream: io, filter: { toolsListChanged: true }, active: false, write_mutex: Mutex.new - } - - @server.notify_tools_list_changed - - assert_empty sse_events(io) - - @transport.send(:activate_listen_subscription, "listen-1") - @server.notify_tools_list_changed - - assert_equal ["notifications/tools/list_changed"], sse_events(io).map { |event| event["method"] } - end - - test "a delivery racing the graceful teardown cannot write after the final result" do - io = open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - entry = @transport.instance_variable_get(:@listen_subscriptions)["listen-1"] - - @transport.close - - # Simulate an in-flight delivery that snapshotted the entry before teardown cleared - # the registry: the closed flag set under the write mutex makes it a no-op. - @transport.instance_variable_get(:@listen_subscriptions)["listen-1"] = entry - @server.notify_tools_list_changed - - events = sse_events(io) - - assert_equal "complete", events.last.dig("result", "resultType") - refute(events.any? { |event| event["method"] == "notifications/tools/list_changed" }) - end - - test "subscriptions/listen streams for different subscriptions receive their own subscriptionId" do - first = open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - second = open_listen_stream(id: "listen-2", notifications: { toolsListChanged: true }) - - @server.notify_tools_list_changed - - first_events = sse_events(first) - second_events = sse_events(second) - assert_equal "listen-1", first_events[1].dig("params", "_meta", "io.modelcontextprotocol/subscriptionId") - assert_equal "listen-2", second_events[1].dig("params", "_meta", "io.modelcontextprotocol/subscriptionId") - end - - test "subscriptions/listen closes gracefully with a SubscriptionsListenResult on transport close" do - io = open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - - @transport.close - - events = sse_events(io) - result = events.last - assert_equal "listen-1", result["id"] - assert_equal "listen-1", result.dig("result", "_meta", "io.modelcontextprotocol/subscriptionId") - # `SubscriptionsListenResult` is a 2026-07-28 result, so it carries the REQUIRED `resultType`. - assert_equal "complete", result.dig("result", "resultType") - assert_predicate io, :closed? - - # The subscription is gone: further notifications are not delivered anywhere. - @server.notify_tools_list_changed - assert_equal events, sse_events(io) - end - - test "subscriptions/listen honoring reads the capability flags, not capability presence" do - # A server declaring `tools` without `listChanged: true` promises no - # list-changed delivery, so the acknowledgement omits the type. - server = Server.new(name: "listen_test", capabilities: { tools: {}, resources: { listChanged: true } }) - transport = StreamableHTTPTransport.new(server) - - io = open_listen_stream( - id: "listen-1", - notifications: { toolsListChanged: true, resourcesListChanged: true, resourceSubscriptions: ["file:///a.txt"] }, - transport: transport, - ) - - ack = sse_events(io)[0] - assert_equal({ "resourcesListChanged" => true }, ack.dig("params", "notifications")) - ensure - transport.close - end - - test "a buffered read of the listen stream body raises guidance instead of NoMethodError" do - response = @transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-1", params: { notifications: { toolsListChanged: true } }), - )) - - error = assert_raises(RuntimeError) { response[2].first } - assert_includes error.message, "serve_subscriptions_listen: false" - - # The cited page is a published-URL contract, like the kwarg name above. - assert_includes error.message, "https://ruby.sdk.modelcontextprotocol.io/server/transports/" - - # Responding to `each` would make Rack classify the body as enumerable and break streaming. - refute_respond_to response[2], :each - end - - test "subscriptions/listen is refused as unimplemented when the transport does not serve it" do - transport = StreamableHTTPTransport.new(@server, serve_subscriptions_listen: false) - - status, headers, body = transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-1", params: { notifications: { toolsListChanged: true } }), - )) - - assert_equal 404, status - assert_equal "application/json", headers["content-type"] - - # The documented Rails controller pattern renders `body.first`, so the refusal must be an Array body, - # never the streaming Proc. - assert_kind_of Array, body - assert_equal(-32601, JSON.parse(body.first).dig("error", "code")) - ensure - transport.close - end - - test "discover stops advertising subscription capabilities when listen is not served" do - server = Server.new( - name: "listen_test", - capabilities: { tools: { listChanged: true }, resources: { listChanged: true, subscribe: true } }, - ) - transport = StreamableHTTPTransport.new(server, serve_subscriptions_listen: false) - - response = transport.handle_request(modern_rack_request(modern_body("server/discover", {}))) - capabilities = JSON.parse(response[2].first).dig("result", "capabilities") - - assert_nil capabilities.dig("tools", "listChanged") - assert_nil capabilities.dig("resources", "listChanged") - assert_nil capabilities.dig("resources", "subscribe") - ensure - transport.close - end - - test "subscriptions/listen past the concurrent stream cap is rejected with 503" do - transport = StreamableHTTPTransport.new(@server, max_listen_subscriptions: 1) - open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }, transport: transport) - - response = transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-2", params: { notifications: { toolsListChanged: true } }), - )) - - assert_equal(503, response[0]) - body = JSON.parse(response[2][0]) - assert_equal("listen-2", body["id"]) - assert_includes(body.dig("error", "message"), "maximum concurrent subscriptions/listen streams") - ensure - transport.close - end - - test "subscriptions/listen rejects a duplicate subscription id by closing the new stream" do - open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - - duplicate = StringIO.new - response = @transport.handle_request(modern_rack_request( - modern_listen_body(id: "listen-1", params: { notifications: { toolsListChanged: true } }), - )) - response[2].call(duplicate) - - assert_predicate duplicate, :closed? - end - - test "listen keepalive writes a comment frame outside the mutex" do - # Register a subscription backed by a mutex-probing stream, then invoke the ping directly. - mutex = @transport.instance_variable_get(:@mutex) - writes = { total: 0, under_mutex: 0 } - ping = nil - stream = Object.new - stream.define_singleton_method(:write) do |data| - writes[:total] += 1 - mutex.try_lock ? mutex.unlock : writes[:under_mutex] += 1 - ping = data - end - stream.define_singleton_method(:flush) {} - @transport.instance_variable_get(:@listen_subscriptions)["listen-1"] = { stream: stream, filter: {}, write_mutex: Mutex.new } - - @transport.send(:send_listen_keepalive_ping, "listen-1") - - assert_equal 1, writes[:total] - assert_equal 0, writes[:under_mutex], "keepalive write must not hold @mutex" - assert_match(/\A: ping /, ping) - end - - test "listen keepalive frees the slot and closes the stream when the peer is gone" do - transport = StreamableHTTPTransport.new(@server, listen_keepalive_interval: 0.01) - io = open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }, transport: transport) - io.define_singleton_method(:write) { |_data| raise Errno::ECONNRESET } - - deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + 2 - until transport.instance_variable_get(:@listen_subscriptions).empty? - flunk("keepalive did not free the slot for a dead peer") if Process.clock_gettime(Process::CLOCK_MONOTONIC) > deadline - sleep(0.01) - end - - assert_predicate io, :closed? - ensure - transport.close - end - - test "listen keepalive is not started when the interval is nil" do - # The set of threads, not their count: `Thread.list` is process-wide, so a thread another test left running - # that finishes between the two samples moves the count in the direction this assertion does not care about. - # Only a thread that appears is evidence of a keepalive timer. - before = Thread.list - open_listen_stream(id: "listen-1", notifications: { toolsListChanged: true }) - - assert_empty(Thread.list - before, "a nil interval must not spawn a keepalive thread") - end - - test "listen_keepalive_interval rejects a non-positive value" do - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, listen_keepalive_interval: 0) } - assert_raises(ArgumentError) { StreamableHTTPTransport.new(@server, listen_keepalive_interval: -1) } + assert_empty(response[1]) + assert_empty(response[2]) end private - def initialize_test_session(id: "init") - init_request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: id, params: initialize_params }.to_json, - ) - @transport.handle_request(init_request)[1]["mcp-session-id"] - end - - # Polls until the block is truthy; the work being awaited happens on another thread. - def wait_until(timeout: 5) - deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + timeout - until yield - flunk("Timed out waiting for condition") if Process.clock_gettime(Process::CLOCK_MONOTONIC) > deadline - sleep(0.01) - end - end - - # Initializes a session on `transport` and attaches a GET SSE stream to it, so - # server-to-client requests have somewhere to go. Returns the session id. - def open_sse_session(transport, io: StringIO.new) - session_id = transport.handle_request(create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ))[1]["mcp-session-id"] - - get_response = transport.handle_request(create_rack_request( - "GET", - "/", - { "HTTP_MCP_SESSION_ID" => session_id }, - )) - get_response[2].call(io) if get_response[2].is_a?(Proc) - wait_until { transport.instance_variable_get(:@sessions).dig(session_id, :get_sse_stream) } - - session_id - end - - # Installs a stream that records, on every write, whether `@mutex` was held at that moment. - # `mutex.try_lock` fails while the transport still holds the lock, so a nonzero `writes[:under_mutex]` - # means a blocking write is being performed under the lock. - def install_mutex_probe_stream(session_id, related_request_id: nil) - mutex = @transport.instance_variable_get(:@mutex) - writes = { total: 0, under_mutex: 0 } - stream = Object.new - stream.define_singleton_method(:write) do |_data| - writes[:total] += 1 - if mutex.try_lock - mutex.unlock - else - writes[:under_mutex] += 1 - end - end - stream.define_singleton_method(:flush) {} - stream.define_singleton_method(:close) {} - - session = @transport.instance_variable_get(:@sessions)[session_id] - if related_request_id - (session[:post_request_streams] ||= {})[related_request_id] = stream - else - session[:get_sse_stream] = stream - end - - writes - end - - # Initializes `transport` and returns its session id together with the `ServerSession`, - # which the in-flight request id tests poll to know when a request has really started. - def start_session(transport) - request = create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json" }, - { jsonrpc: "2.0", method: "initialize", id: "init", params: initialize_params }.to_json, - ) - session_id = transport.handle_request(request)[1]["mcp-session-id"] - - [session_id, transport.instance_variable_get(:@sessions)[session_id][:server_session]] - end - - # A `tools/call` for `victim_tool` under a caller-chosen request id, with a progress token so - # the tool's `report_progress` has somewhere to go. - def colliding_tool_call(session_id, request_id) - create_rack_request( - "POST", - "/", - { "CONTENT_TYPE" => "application/json", "HTTP_MCP_SESSION_ID" => session_id }, - { - jsonrpc: "2.0", - id: request_id, - method: "tools/call", - params: { name: "victim_tool", arguments: {}, _meta: { progressToken: "tok" } }, - }.to_json, - ) - end - def create_rack_request(method, path, headers, body = nil) default_accept = case method when "POST" @@ -6449,86 +956,6 @@ module MCP Rack::Request.new(env) end - - # Builds a POST request routed to the modern path via the `MCP-Protocol-Version` header. - # Mirrors what a conforming modern client sends: `Mcp-Method` is required on every modern POST - # and `Mcp-Name` on a name-bearing method whose body carries a target name, so both default to - # the body's values. Pass `method_header: nil` / `name_header: nil` to omit one - # (for tests of the requirement itself) or a String to send a specific value. - def modern_rack_request(body, version: "2026-07-28", headers: {}, method_header: :from_body, - name_header: :from_body) - parsed = begin - JSON.parse(body) - rescue JSON::ParserError - nil - end - parsed = nil unless parsed.is_a?(Hash) - - derived_method = method_header == :from_body ? parsed&.dig("method") : method_header - derived_name = if name_header == :from_body - if StreamableHTTPTransport::NAME_BEARING_METHODS.include?(parsed&.dig("method")) - parsed.dig("params", "name") || parsed.dig("params", "uri") - end - else - name_header - end - - base_headers = { "CONTENT_TYPE" => "application/json", "HTTP_MCP_PROTOCOL_VERSION" => version } - base_headers["HTTP_MCP_METHOD"] = derived_method if derived_method - base_headers["HTTP_MCP_NAME"] = derived_name if derived_name - create_rack_request("POST", "/", base_headers.merge(headers), body) - end - - # Builds a JSON-RPC body carrying the SEP-2575 modern `_meta` envelope. - def modern_body(method, params, version: "2026-07-28", capabilities: {}) - { - jsonrpc: "2.0", - method: method, - id: 1, - params: params.merge( - _meta: { - "io.modelcontextprotocol/protocolVersion": version, - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": capabilities, - }, - ), - }.to_json - end - - def modern_listen_body(id:, params:) - { - jsonrpc: "2.0", - method: "subscriptions/listen", - id: id, - params: params.merge( - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": {}, - }, - ), - }.to_json - end - - # Opens a `subscriptions/listen` stream on the modern path and returns the StringIO - # backing the SSE stream (already carrying the acknowledgement event). - def open_listen_stream(id:, notifications:, transport: @transport) - response = transport.handle_request(modern_rack_request( - modern_listen_body(id: id, params: { notifications: notifications }), - )) - - assert_equal(200, response[0]) - assert_equal("text/event-stream", response[1]["content-type"]) - - io = StringIO.new - response[2].call(io) - io - end - - # Parses every `data:` event written to an SSE StringIO. - def sse_events(io) - io.string.scan(/^data: (.+)$/).map { |match| JSON.parse(match[0]) } - end end end end diff --git a/test/mcp/server_cancellation_test.rb b/test/mcp/server_cancellation_test.rb deleted file mode 100644 index 9fc28cf..0000000 --- a/test/mcp/server_cancellation_test.rb +++ /dev/null @@ -1,786 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerCancellationTest < ActiveSupport::TestCase - include InstrumentationTestHelper - include InitializeParamsTestHelper - - class MockTransport < Transport - attr_reader :requests, :notifications, :cancelled_request_ids - - def initialize(server) - super - @requests = [] - @notifications = [] - @cancelled_request_ids = [] - end - - def send_request(method, params = nil, **_kwargs) - @requests << { method: method, params: params } - {} - end - - def send_notification(method, params = nil, **_kwargs) - @notifications << { method: method, params: params } - true - end - - def cancel_pending_request(request_id, reason: nil) - @cancelled_request_ids << request_id - end - - def send_response(response); end - def open; end - def close; end - def handle_request(request); end - end - - setup do - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - - @server = Server.new(name: "test_server", version: "1.0.0", configuration: configuration) - @mock_transport = MockTransport.new(@server) - @server.transport = @mock_transport - @session = ServerSession.new(server: @server, transport: @mock_transport, session_id: "sess-1") - end - - test "cooperative cancellation via server_context suppresses response" do - observed_cancelled = false - - @server.define_tool(name: "slow") do |server_context:| - 20.times do - break if server_context.cancelled? - - sleep(0.01) - end - observed_cancelled = server_context.cancelled? - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request_id = 42 - - call_thread = Thread.new do - @session.handle( - jsonrpc: "2.0", - id: request_id, - method: Methods::TOOLS_CALL, - params: { name: "slow", arguments: {} }, - ) - end - - sleep(0.02) until @session.lookup_in_flight(request_id) - - @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "user aborted" }, - ) - - response = call_thread.value - - assert observed_cancelled, "tool handler should observe cancellation" - assert_nil response, "cancelled request must not emit a JSON-RPC response" - end - - test "tool raising CancelledError via raise_if_cancelled! suppresses the JSON-RPC response" do - @server.define_tool(name: "raising") do |server_context:| - 50.times do - server_context.raise_if_cancelled! - sleep(0.01) - end - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request_id = 99 - - call_thread = Thread.new do - @session.handle( - jsonrpc: "2.0", - id: request_id, - method: Methods::TOOLS_CALL, - params: { name: "raising", arguments: {} }, - ) - end - - sleep(0.02) until @session.lookup_in_flight(request_id) - - @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "raised" }, - ) - - response = call_thread.value - - assert_nil response, "raise_if_cancelled! must result in no JSON-RPC response" - end - - test "CancelledError raised from nested server-to-client call suppresses response" do - @server.define_tool(name: "nesting") do |**| - # Simulate a transport-level CancelledError coming back from a nested - # send_request (e.g. sampling/createMessage after parent was cancelled). - raise MCP::CancelledError.new(request_id: "nested-xyz", reason: "parent aborted") - end - - response = @session.handle( - jsonrpc: "2.0", - id: 123, - method: Methods::TOOLS_CALL, - params: { name: "nesting", arguments: {} }, - ) - - assert_nil response, "CancelledError propagating from a nested call must suppress the JSON-RPC response" - end - - test "cancellation with unknown request id is silently ignored" do - response = @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: "does-not-exist" }, - ) - - assert_nil response - end - - test "id-bearing notifications/cancelled is rejected with Method not found, not result: null" do - response = @session.handle( - jsonrpc: "2.0", - id: 1001, - method: Methods::NOTIFICATIONS_CANCELLED, - ) - - assert_equal 1001, response[:id] - refute response.key?(:result) - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code) - end - - test "id-bearing notifications/initialized is rejected with Method not found" do - response = @session.handle( - jsonrpc: "2.0", - id: 1002, - method: Methods::NOTIFICATIONS_INITIALIZED, - ) - - assert_equal 1002, response[:id] - refute response.key?(:result) - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code) - end - - test "id-bearing notifications/progress is rejected with Method not found" do - response = @session.handle( - jsonrpc: "2.0", - id: 1003, - method: Methods::NOTIFICATIONS_PROGRESS, - params: { progressToken: "tok", progress: 1 }, - ) - - assert_equal 1003, response[:id] - refute response.key?(:result) - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code) - end - - test "well-formed notifications/initialized still receives no response" do - response = @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_INITIALIZED, - ) - - assert_nil response - end - - test "id-bearing notification mixed into a batch yields only its Method not found error" do - responses = @session.handle([ - { jsonrpc: "2.0", method: Methods::NOTIFICATIONS_CANCELLED, params: { requestId: "x" } }, - { jsonrpc: "2.0", id: 2001, method: Methods::NOTIFICATIONS_CANCELLED }, - { jsonrpc: "2.0", id: 2002, method: Methods::PING }, - ]) - - cancelled_error = responses.find { |response| response[:id] == 2001 } - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, cancelled_error.dig(:error, :code) - - ping_response = responses.find { |response| response[:id] == 2002 } - assert_equal({}, ping_response[:result]) - - # The well-formed notification carries no id and contributes no response. - assert_equal 2, responses.size - end - - test "id-bearing custom notifications/* method is rejected with Method not found" do - called = false - @server.define_custom_method(method_name: "notifications/custom") { called = true } - - response = @session.handle( - jsonrpc: "2.0", - id: 3001, - method: "notifications/custom", - ) - - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code) - refute called - end - - test "well-formed custom notifications/* method is dispatched without a response" do - called = false - @server.define_custom_method(method_name: "notifications/custom") { called = true } - - response = @session.handle( - jsonrpc: "2.0", - method: "notifications/custom", - ) - - assert_nil response - assert called - end - - test "duplicate cancellation for the same in-flight request is idempotent" do - @server.define_tool(name: "slow_dup") do |server_context:| - 20.times do - break if server_context.cancelled? - - sleep(0.01) - end - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request_id = 51 - - call_thread = Thread.new do - @session.handle( - jsonrpc: "2.0", - id: request_id, - method: Methods::TOOLS_CALL, - params: { name: "slow_dup", arguments: {} }, - ) - end - - sleep(0.02) until @session.lookup_in_flight(request_id) - - first = @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "first" }, - ) - - second = @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "second" }, - ) - - response = call_thread.value - - assert_nil first - assert_nil second, "duplicate cancel must not emit a response" - assert_nil response, "cancelled request must not emit a response" - end - - test "cancellation arriving after the request already completed is silently ignored" do - @server.define_tool(name: "quick") do - Tool::Response.new([{ type: "text", text: "done" }]) - end - - request_id = 61 - - response = @session.handle( - jsonrpc: "2.0", - id: request_id, - method: Methods::TOOLS_CALL, - params: { name: "quick", arguments: {} }, - ) - - assert response, "the tool should have completed successfully before the cancel arrives" - assert_nil @session.lookup_in_flight(request_id), "completed request must be unregistered" - - late = @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "late" }, - ) - - assert_nil late, "late cancel for a completed request must be silently ignored" - end - - test "initialize request cannot be cancelled" do - init_params = { - protocolVersion: Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, - clientInfo: { name: "test", version: "1.0" }, - capabilities: {}, - } - - response = @session.handle( - jsonrpc: "2.0", - id: "init-1", - method: Methods::INITIALIZE, - params: init_params, - ) - - assert response, "initialize returns a response" - assert response[:result][:protocolVersion] - # The initialize request is not registered in the in-flight map. - assert_nil @session.lookup_in_flight("init-1") - end - - test "ServerSession#cancel_request sends notification and cancels pending" do - @session.cancel_request(request_id: "req-9", reason: "timeout") - - notification = @mock_transport.notifications.last - assert_equal Methods::NOTIFICATIONS_CANCELLED, notification[:method] - assert_equal "req-9", notification[:params][:requestId] - assert_equal "timeout", notification[:params][:reason] - - assert_includes @mock_transport.cancelled_request_ids, "req-9" - end - - test "register_in_flight refuses an id that is already in flight" do - first = @session.register_in_flight("req-1") - - assert first - assert_nil @session.register_in_flight("req-1"), "a second live request cannot share the id" - assert_same first, @session.lookup_in_flight("req-1"), "the first registration must survive" - end - - test "unregister_in_flight leaves a registration it does not own" do - owner = @session.register_in_flight("req-1") - @session.unregister_in_flight("req-1", cancellation: Cancellation.new(request_id: "req-1")) - - assert_same owner, @session.lookup_in_flight("req-1") - - @session.unregister_in_flight("req-1", cancellation: owner) - - assert_nil @session.lookup_in_flight("req-1") - end - - test "in_flight? reports whether an id is registered" do - refute @session.in_flight?("req-1") - - @session.register_in_flight("req-1") - - assert @session.in_flight?("req-1") - end - - test "a request reusing an in-flight id is answered with Invalid Request" do - @server.define_tool(name: "slow") do |server_context:| - sleep(0.2) - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request = { - jsonrpc: "2.0", - id: "req-1", - method: Methods::TOOLS_CALL, - params: { name: "slow", arguments: {} }, - } - - in_flight = Thread.new { @session.handle(request) } - sleep(0.01) until @session.lookup_in_flight("req-1") - - duplicate = @session.handle(request) - - assert_equal( - JsonRpcHandler::ErrorCode::INVALID_REQUEST, - duplicate.dig(:error, :code) || duplicate.dig("error", "code"), - ) - in_flight.join - end - - test "a refused duplicate initialize leaves an in-flight registration under its reused id" do - @session.handle(jsonrpc: "2.0", id: "init", method: Methods::INITIALIZE, params: initialize_params) - - owner = @session.register_in_flight("req-1") - - # `initialize` bypasses the duplicate-id refusal (it is never in flight itself), so its - # rejection path is the one place a reused id reaches a handler while the id is still live. - duplicate = @session.handle(jsonrpc: "2.0", id: "req-1", method: Methods::INITIALIZE, params: initialize_params) - - assert_equal( - JsonRpcHandler::ErrorCode::INVALID_REQUEST, - duplicate.dig(:error, :code) || duplicate.dig("error", "code"), - ) - assert_same owner, @session.lookup_in_flight("req-1"), "the registration must survive the refused initialize" - end - - test "parent cancellation propagates to nested server-to-client requests" do - @session.instance_variable_set(:@client_capabilities, { elicitation: {} }) - - parent_request_id = 101 - cancellation = @session.register_in_flight(parent_request_id) - - # Simulate a nested sampling/elicitation send via ServerSession. The transport - # is expected to receive `parent_cancellation:` and `server_session:` kwargs so - # it can install an `on_cancel` hook. Here we assert those kwargs are forwarded. - recorded = {} - (class << @mock_transport; self; end).define_method(:send_request) do |method, _params = nil, **kwargs| - recorded[:method] = method - recorded[:kwargs] = kwargs - {} - end - - @session.create_form_elicitation( - message: "ignored", - requested_schema: { type: "object", properties: {} }, - related_request_id: parent_request_id, - ) - - assert_equal Methods::ELICITATION_CREATE, recorded[:method] - assert_equal parent_request_id, recorded[:kwargs][:related_request_id] - assert_same cancellation, recorded[:kwargs][:parent_cancellation] - assert_same @session, recorded[:kwargs][:server_session] - end - - test "cancellation reason is recorded in instrumentation data" do - recorded_data = nil - @server.configuration.instrumentation_callback = ->(data) { recorded_data = data } - - @server.define_tool(name: "slow_with_reason") do |server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request_id = 77 - - call_thread = Thread.new do - @session.handle( - jsonrpc: "2.0", - id: request_id, - method: Methods::TOOLS_CALL, - params: { name: "slow_with_reason", arguments: {} }, - ) - end - - sleep(0.02) until @session.lookup_in_flight(request_id) - - @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "explicit reason string" }, - ) - - call_thread.value - - assert recorded_data - assert recorded_data[:cancelled] - assert_equal "explicit reason string", recorded_data[:cancellation_reason] - end - - # Helper for the non-tools cancellation regression tests below. Spawns a background - # request, waits for the in-flight entry, sends `notifications/cancelled`, and - # returns [response, thread_result_flag_yielded_by_block]. - def drive_cancellation(request_id:, method:, params:) - result_flag = { observed: false } - call_thread = Thread.new do - @session.handle(jsonrpc: "2.0", id: request_id, method: method, params: params) - end - - sleep(0.02) until @session.lookup_in_flight(request_id) - - yield(result_flag) if block_given? - - @session.handle( - jsonrpc: "2.0", - method: Methods::NOTIFICATIONS_CANCELLED, - params: { requestId: request_id, reason: "caller aborted" }, - ) - - [call_thread.value, result_flag] - end - - test "resources/read handler that opts in to server_context observes cancellation" do - observed = false - @server.resources_read_handler do |_params, server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - observed = server_context.cancelled? - [{ uri: "test://resource", text: "done" }] - end - - response, = drive_cancellation( - request_id: 201, - method: Methods::RESOURCES_READ, - params: { uri: "test://resource" }, - ) - - assert observed, "resources/read handler should observe cancellation via server_context" - assert_nil response, "cancelled resources/read must not emit a JSON-RPC response" - end - - test "completion/complete handler that opts in to server_context observes cancellation" do - observed = false - @server.capabilities[:completions] = {} - @server.completion_handler do |_params, server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - observed = server_context.cancelled? - { completion: { values: ["v"], hasMore: false } } - end - - # completion/complete requires a known ref; register a dummy prompt. - @server.define_prompt(name: "dummy") { MCP::Prompt::Result.new(messages: []) } - - response, = drive_cancellation( - request_id: 202, - method: Methods::COMPLETION_COMPLETE, - params: { ref: { type: "ref/prompt", name: "dummy" }, argument: { name: "arg", value: "" } }, - ) - - assert observed, "completion/complete handler should observe cancellation via server_context" - assert_nil response, "cancelled completion/complete must not emit a JSON-RPC response" - end - - test "prompts/get template that opts in to server_context observes cancellation" do - observed = false - prompt_class = Class.new(MCP::Prompt) do - prompt_name "slow_prompt" - - define_singleton_method(:template) do |_args, server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - observed = server_context.cancelled? - MCP::Prompt::Result.new(messages: []) - end - end - @server.prompts[prompt_class.name_value] = prompt_class - # Share `observed` between the closure above and the test scope. - @server.singleton_class.define_method(:_test_observed) { observed } - - response, = drive_cancellation( - request_id: 203, - method: Methods::PROMPTS_GET, - params: { name: "slow_prompt" }, - ) - - assert observed, "prompt template should observe cancellation via server_context" - assert_nil response, "cancelled prompts/get must not emit a JSON-RPC response" - end - - test "send_to_transport (notifications) works with a custom transport that only implements the abstract signature" do - # Regression: `ServerSession#send_to_transport` must not assume the - # transport's `send_notification` accepts the new kwargs - # (`session_id:` / `related_request_id:`). Custom transports that - # implement the abstract `Transport#send_notification(method, params = nil)` - # contract must keep working - this is exercised via `cancel_request` / - # `send_peer_cancellation` which the cancellation feature relies on. - minimal_transport = Class.new(Transport) do - attr_reader :recorded - - def initialize(server) - super - @recorded = [] - end - - def send_notification(method, params = nil) - @recorded << [method, params] - true - end - - def send_request(method, params = nil) - @recorded << [method, params] - {} - end - - def send_response(_); end - def open; end - def close; end - end.new(@server) - - session = ServerSession.new(server: @server, transport: minimal_transport) - - assert_nothing_raised do - session.cancel_request(request_id: "req-1", reason: "timeout") - end - - recorded = minimal_transport.recorded.last - assert_equal Methods::NOTIFICATIONS_CANCELLED, recorded[0] - assert_equal "req-1", recorded[1][:requestId] - assert_equal "timeout", recorded[1][:reason] - end - - test "send_to_transport_request works with a custom transport that only implements the abstract signature" do - # Regression: `ServerSession#send_to_transport_request` must not assume - # the transport's `send_request` accepts the new kwargs - # (`session_id:` / `related_request_id:` / `parent_cancellation:` / - # `server_session:`). Custom transports that implement the abstract - # `Transport#send_request(method, params = nil)` contract must keep working. - minimal_transport = Class.new(Transport) do - attr_reader :recorded - - def initialize(server) - super - @recorded = [] - end - - def send_request(method, params = nil) - @recorded << [method, params] - {} # fake response - end - - def send_notification(method, params = nil) - @recorded << [method, params] - true - end - - def send_response(_); end - def open; end - def close; end - end.new(@server) - - session = ServerSession.new(server: @server, transport: minimal_transport) - session.instance_variable_set(:@client_capabilities, { sampling: {} }) - - assert_nothing_raised do - session.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "hi" } }], - max_tokens: 10, - ) - end - - recorded = minimal_transport.recorded.last - assert_equal Methods::SAMPLING_CREATE_MESSAGE, recorded[0] - refute_nil recorded[1] - end - - test "tool with positional `server_context` parameter is not auto-opted-in" do - # Regression: `accepts_server_context?` (used by tool/prompt dispatch) must - # require `server_context` as a *keyword* parameter. A tool whose `call` - # signature is `def self.call(arg, server_context)` (positional name collision) - # would previously have been opt-in, and `tool.call(**args, server_context: ctx)` - # would have blown up or passed the wrapped Hash to the wrong slot. - tool = Class.new(MCP::Tool) do - tool_name "positional_collision" - input_schema(properties: { a: { type: "string" } }, required: ["a"]) - - class << self - def call(a, server_context) - [a, server_context] - end - end - end - @server.tools[tool.name_value] = tool - - # Should dispatch without `server_context:` kwarg - the positional arg collision - # must NOT trigger opt-in. The tool receives only its declared positional (a). - response = @session.handle( - jsonrpc: "2.0", - id: 303, - method: Methods::TOOLS_CALL, - params: { name: "positional_collision", arguments: { a: "hello" } }, - ) - - # Because the tool signature isn't opt-in, `tool.call(**args)` is called - # (without `server_context:`). The method has `server_context` as a required - # positional, so missing it raises ArgumentError - caught as an internal error. - # The key assertion is that we do NOT pass `server_context:` kwarg that would - # flow into the positional slot as a Hash. - assert response.dig(:error), "dispatch should not silently inject server_context kwarg" - end - - test "handler with positional `server_context` parameter is not auto-opted-in" do - # Regression: `handler_declares_server_context?` must require `server_context` - # as a *keyword* parameter. A positional parameter that happens to be named - # `server_context` (rare but possible) would previously have been treated as - # opt-in, and the dispatch site would call `handler.call(params, server_context: ctx)` - # - the second positional argument would become the Hash `{server_context: ctx}`, - # which is never what the user intended. - received_args = nil - @server.define_custom_method(method_name: "custom/positional_name") do |params, server_context| - received_args = [params, server_context] - { ok: true } - end - - response = @session.handle( - jsonrpc: "2.0", - id: 302, - method: "custom/positional_name", - params: { hello: "world" }, - ) - - assert_equal [{ hello: "world" }, nil], - received_args, - "positional `server_context` must receive the single `params` argument, not an auto-wrapped context" - assert_equal({ ok: true }, response[:result]) - end - - test "handler with **kwargs-only signature is not auto-opted-in to server_context" do - # Regression: a block like `|**opts|` would have triggered opt-in under the - # looser `accepts_server_context?` check used by tools, and the dispatch site - # would then call `handler.call(params, server_context:)` - but a proc that - # only declares `**opts` cannot accept the positional `params` (lambdas raise - # ArgumentError, non-lambda procs silently drop it). The stricter - # `handler_declares_server_context?` check requires `server_context` as a - # named keyword to opt in, so a kwargs-only handler receives only `params`. - received_positional = nil - @server.define_custom_method(method_name: "custom/kwargs_only") do |params, **_opts| - received_positional = params - { ok: true } - end - - response = @session.handle( - jsonrpc: "2.0", - id: 301, - method: "custom/kwargs_only", - params: { hello: "world" }, - ) - - assert_equal({ hello: "world" }, received_positional) - assert_equal({ ok: true }, response[:result]) - end - - test "custom method handler that opts in to server_context observes cancellation" do - observed = false - @server.define_custom_method(method_name: "custom/slow") do |_params, server_context:| - 50.times do - break if server_context.cancelled? - - sleep(0.01) - end - observed = server_context.cancelled? - { ok: true } - end - - response, = drive_cancellation( - request_id: 204, - method: "custom/slow", - params: {}, - ) - - assert observed, "custom method handler should observe cancellation via server_context" - assert_nil response, "cancelled custom method must not emit a JSON-RPC response" - end - - test "send_peer_cancellation routes notification on parent stream via related_request_id" do - recorded_notifications = [] - (class << @mock_transport; self; end).define_method(:send_notification) do |method, params = nil, **kwargs| - recorded_notifications << { method: method, params: params, kwargs: kwargs } - true - end - - @session.send_peer_cancellation( - nested_request_id: "nested-1", - related_request_id: 42, - reason: "parent aborted", - ) - - notif = recorded_notifications.last - assert_equal Methods::NOTIFICATIONS_CANCELLED, notif[:method] - assert_equal "nested-1", notif[:params][:requestId] - assert_equal "parent aborted", notif[:params][:reason] - # Crucially, the cancel notification targets the parent's stream, not the GET SSE stream. - assert_equal 42, notif[:kwargs][:related_request_id] - end - end -end diff --git a/test/mcp/server_context_test.rb b/test/mcp/server_context_test.rb index 10089c5..8307af5 100644 --- a/test/mcp/server_context_test.rb +++ b/test/mcp/server_context_test.rb @@ -4,430 +4,6 @@ require "test_helper" module MCP class ServerContextTest < ActiveSupport::TestCase - test "ServerContext delegates method calls to the underlying context" do - context = { user: "test_user" } - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - assert_equal "test_user", server_context[:user] - end - - test "ServerContext respond_to? returns true for methods on the underlying context" do - context = { user: "test_user" } - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - assert_respond_to server_context, :[] - assert_respond_to server_context, :keys - end - - test "ServerContext respond_to? returns false for methods not on the underlying context" do - context = { user: "test_user" } - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - refute_respond_to server_context, :nonexistent_method - end - - test "ServerContext raises NoMethodError for methods not on the underlying context" do - context = { user: "test_user" } - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - assert_raises(NoMethodError) { server_context.nonexistent_method } - end - - test "ServerContext#list_roots delegates to notification_target" do - notification_target = mock - notification_target.expects(:list_roots).with( - related_request_id: nil, - ).returns({ roots: [{ uri: "file:///project", name: "Project" }] }) - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.list_roots - - assert_equal [{ uri: "file:///project", name: "Project" }], result[:roots] - end - - test "ServerContext#list_roots stamps the originating request id" do - # Per SEP-2260, server-to-client requests are associated with the originating client request automatically. - notification_target = mock - notification_target.expects(:list_roots).with(related_request_id: "req-1").returns({ roots: [] }) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new( - mock, - progress: progress, - notification_target: notification_target, - related_request_id: "req-1", - ) - - server_context.list_roots - end - - test "ServerContext#create_sampling_message stamps related_request_id non-overridably" do - # A caller-supplied `related_request_id:` must not detach the request from its originating client request (SEP-2260): - # the literal keyword after `**kwargs` wins. - notification_target = mock - notification_target.expects(:create_sampling_message).with( - messages: [], - max_tokens: 5, - related_request_id: "req-1", - ).returns({}) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new( - mock, - progress: progress, - notification_target: notification_target, - related_request_id: "req-1", - ) - - server_context.create_sampling_message(messages: [], max_tokens: 5, related_request_id: "attacker") - end - - test "ServerContext#create_form_elicitation stamps related_request_id non-overridably" do - notification_target = mock - notification_target.expects(:create_form_elicitation).with( - message: "hi", - requested_schema: {}, - related_request_id: "req-1", - ).returns({}) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new( - mock, - progress: progress, - notification_target: notification_target, - related_request_id: "req-1", - ) - - server_context.create_form_elicitation(message: "hi", requested_schema: {}, related_request_id: "attacker") - end - - test "ServerContext#create_url_elicitation stamps related_request_id non-overridably" do - notification_target = mock - notification_target.expects(:create_url_elicitation).with( - message: "hi", - url: "https://example.com", - elicitation_id: "el-1", - related_request_id: "req-1", - ).returns({}) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new( - mock, - progress: progress, - notification_target: notification_target, - related_request_id: "req-1", - ) - - server_context.create_url_elicitation( - message: "hi", - url: "https://example.com", - elicitation_id: "el-1", - related_request_id: "attacker", - ) - end - - test "ServerContext#list_roots raises NoMethodError when notification_target does not respond" do - notification_target = mock - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - assert_raises(NoMethodError) { server_context.list_roots } - end - - test "ServerContext#ping delegates to notification_target" do - notification_target = mock - notification_target.expects(:ping).with(related_request_id: nil).returns({}) - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.ping - - assert_equal({}, result) - end - - test "ServerContext forwards a per-request timeout to the notification target" do - notification_target = mock - notification_target.expects(:ping).with(related_request_id: nil, timeout: 12).returns({}) - notification_target.expects(:list_roots).with(related_request_id: nil, timeout: 34).returns({ roots: [] }) - notification_target.expects(:create_form_elicitation).with( - message: "Approve?", - requested_schema: { type: "object", properties: {} }, - related_request_id: nil, - timeout: 56, - ).returns({ action: "accept" }) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new(mock, progress: progress, notification_target: notification_target) - - server_context.ping(timeout: 12) - server_context.list_roots(timeout: 34) - server_context.create_form_elicitation( - message: "Approve?", - requested_schema: { type: "object", properties: {} }, - timeout: 56, - ) - end - - test "ServerContext omits timeout entirely when the caller does not ask for one" do - # A notification target predating the keyword (a custom object standing in for a session) keeps working, - # and the transport applies its own default. - notification_target = mock - notification_target.expects(:ping).with(related_request_id: nil).returns({}) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new(mock, progress: progress, notification_target: notification_target) - - server_context.ping - end - - test "ServerContext#ping raises NoMethodError when notification_target does not respond" do - notification_target = mock - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - assert_raises(NoMethodError) { server_context.ping } - end - - test "ServerContext#create_sampling_message delegates to notification_target over context" do - notification_target = mock - notification_target.expects(:create_sampling_message).with( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - related_request_id: nil, - ).returns({ role: "assistant", content: { type: "text", text: "Hi" } }) - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - - assert_equal "Hi", result[:content][:text] - end - - test "ServerContext#create_sampling_message falls back to context when notification_target does not respond" do - notification_target = mock - context = mock - context.expects(:create_sampling_message).with( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - related_request_id: nil, - ).returns({ role: "assistant", content: { type: "text", text: "Fallback" } }) - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - - assert_equal "Fallback", result[:content][:text] - end - - test "ServerContext#create_form_elicitation delegates to notification_target" do - notification_target = mock - notification_target.expects(:create_form_elicitation).with( - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - related_request_id: nil, - ).returns(action: "accept", content: { name: "test_user" }) - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.create_form_elicitation( - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - ) - - assert_equal "accept", result[:action] - end - - test "ServerContext#create_url_elicitation delegates to notification_target" do - notification_target = mock - notification_target.expects(:create_url_elicitation).with( - message: "Please authorize", - url: "https://example.com/oauth", - elicitation_id: "abc-123", - related_request_id: nil, - ).returns(action: "accept") - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - result = server_context.create_url_elicitation( - message: "Please authorize", - url: "https://example.com/oauth", - elicitation_id: "abc-123", - ) - - assert_equal "accept", result[:action] - end - - test "ServerContext#notify_elicitation_complete delegates to notification_target" do - notification_target = mock - notification_target.expects(:notify_elicitation_complete).with(elicitation_id: "abc-123") - - context = mock - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: notification_target) - - server_context.notify_elicitation_complete(elicitation_id: "abc-123") - end - - test "ServerContext delegates to custom object context" do - context = Object.new - def context.custom_method - "custom_value" - end - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - assert_equal "custom_value", server_context.custom_method - end - - test "ServerContext forwards positional, keyword, and block arguments to the context" do - context = Object.new - def context.combine(prefix, suffix:, &block) - block.call("#{prefix}-#{suffix}") - end - progress = Progress.new(notification_target: mock, progress_token: nil) - - server_context = ServerContext.new(context, progress: progress, notification_target: mock) - - result = server_context.combine("a", suffix: "b", &:upcase) - - assert_equal "A-B", result - end - - test "ServerContext#report_progress works with nil context" do - progress = mock - progress.expects(:report).with(50, total: 100, message: nil).once - - server_context = ServerContext.new(nil, progress: progress, notification_target: mock) - server_context.report_progress(50, total: 100) - end - - test "ServerContext#notify_log_message is a no-op when notification_target is nil" do - progress = Progress.new(notification_target: nil, progress_token: nil) - server_context = ServerContext.new(nil, progress: progress, notification_target: nil) - - assert_nothing_raised { server_context.notify_log_message(data: "test", level: "info") } - end - - test "ServerContext#notify_log_message drops messages on modern requests without a logLevel" do - # Per SEP-2575, without `io.modelcontextprotocol/logLevel` in `_meta`, the server MUST NOT send - # any `notifications/message` for the request. - notification_target = mock - notification_target.expects(:notify_log_message).never - server_context = build_modern_server_context(notification_target, log_level: nil) - - server_context.notify_log_message(data: "test", level: "error") - end - - test "ServerContext#notify_log_message drops messages below the modern request logLevel" do - notification_target = mock - notification_target.expects(:notify_log_message).never - server_context = build_modern_server_context(notification_target, log_level: "error") - - server_context.notify_log_message(data: "test", level: "info") - end - - test "ServerContext#notify_log_message delegates messages at or above the modern request logLevel" do - notification_target = mock - notification_target.expects(:notify_log_message).with( - data: "test", level: "error", logger: nil, related_request_id: nil, - ).once - server_context = build_modern_server_context(notification_target, log_level: "warning") - - server_context.notify_log_message(data: "test", level: "error") - end - - test "ServerContext exposes envelope data and falls back to the session on legacy requests" do - notification_target = mock - notification_target.stubs(:client).returns({ name: "legacy_client", version: "1.0" }) - notification_target.stubs(:client_capabilities).returns({ roots: {} }) - progress = Progress.new(notification_target: notification_target, progress_token: nil) - - legacy_context = ServerContext.new(nil, progress: progress, notification_target: notification_target) - modern_context = build_modern_server_context(notification_target) - - refute_predicate legacy_context, :modern? - assert_equal({ name: "legacy_client", version: "1.0" }, legacy_context.client_info) - assert_equal({ roots: {} }, legacy_context.client_capabilities) - assert_nil legacy_context.protocol_version - - assert_predicate modern_context, :modern? - assert_equal({ name: "modern_client", version: "2.0" }, modern_context.client_info) - assert_equal({ elicitation: { form: {} } }, modern_context.client_capabilities) - assert_equal "2026-07-28", modern_context.protocol_version - end - - test "ServerContext#require_client_capability! matches string-keyed capabilities and requires a path" do - envelope = RequestEnvelope.new( - protocol_version: "2026-07-28", - client_info: { name: "c", version: "1" }, - client_capabilities: { "elicitation" => { "form" => {} } }, - ) - progress = Progress.new(notification_target: nil, progress_token: nil) - server_context = ServerContext.new(nil, progress: progress, notification_target: nil, envelope: envelope) - - assert_nothing_raised { server_context.require_client_capability!(:elicitation, :form) } - assert_raises(ArgumentError) { server_context.require_client_capability! } - error = assert_raises(Server::MissingRequiredClientCapabilityError) do - server_context.require_client_capability!(:sampling) - end - assert_equal({ requiredCapabilities: { sampling: {} } }, error.error_data) - end - - test "ServerContext#notify_resources_updated delegates to notification_target" do - notification_target = mock - notification_target.expects(:notify_resources_updated).with(uri: "test://resource-1").once - - progress = Progress.new(notification_target: notification_target, progress_token: nil) - server_context = ServerContext.new(nil, progress: progress, notification_target: notification_target) - - server_context.notify_resources_updated(uri: "test://resource-1") - end - - test "ServerContext#notify_resources_updated is a no-op when notification_target is nil" do - progress = Progress.new(notification_target: nil, progress_token: nil) - server_context = ServerContext.new(nil, progress: progress, notification_target: nil) - - assert_nothing_raised { server_context.notify_resources_updated(uri: "test://resource-1") } - end - # Tool without server_context parameter class SimpleToolWithoutContext < Tool tool_name "simple_without_context" @@ -451,8 +27,7 @@ module MCP class << self def call(message:, server_context: nil) - user = server_context.respond_to?(:[]) ? server_context[:user] : nil - context_info = user ? "with context: #{user}" : "no context" + context_info = server_context ? "with context: #{server_context[:user]}" : "no context" Tool::Response.new([ { type: "text", content: "ToolWithOptionalContext: #{message} (#{context_info})" }, ]) @@ -559,7 +134,7 @@ module MCP response[:result][:content][0][:content] end - test "tool with required server_context returns protocol error in JSON-RPC format when server has no context" do + test "tool with required server_context fails when server has no context" do server_no_context = Server.new( name: "test_server_no_context", tools: [ToolWithRequiredContext], @@ -577,10 +152,10 @@ module MCP response = server_no_context.handle(request) - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool tool_with_required_context", response[:error][:data] + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_match(/Internal error calling tool tool_with_required_context: /, response[:result][:content][0][:text]) end test "call_tool_with_args correctly detects server_context parameter presence" do @@ -666,8 +241,7 @@ module MCP class << self def template(args, server_context: nil) - user = server_context.respond_to?(:[]) ? server_context[:user] : nil - context_info = user ? "with context: #{user}" : "no context" + context_info = server_context ? "with context: #{server_context[:user]}" : "no context" Prompt::Result.new( messages: [ Prompt::Message.new( @@ -840,278 +414,5 @@ module MCP assert_equal "FlexiblePrompt: Hello (context: present)", response[:result][:messages][0][:content][:text] end - - test "tool receives _meta when provided in request params" do - class ToolWithMeta < Tool - tool_name "tool_with_meta" - description "A tool that uses _meta" - input_schema({ properties: { message: { type: "string" } }, required: ["message"] }) - - class << self - def call(message:, server_context:) - meta_info = server_context.dig(:_meta, :provider, :metadata) - Tool::Response.new([ - { type: "text", content: "Message: #{message}, Metadata: #{meta_info}" }, - ]) - end - end - end - - server = Server.new( - name: "test_server", - tools: [ToolWithMeta], - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_meta", - arguments: { message: "Hello" }, - _meta: { - provider: { - metadata: "test_value", - }, - }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "Message: Hello, Metadata: test_value", - response[:result][:content][0][:content] - end - - test "_meta is nested within server_context" do - class ToolWithNestedMeta < Tool - tool_name "tool_with_nested_meta" - description "A tool that uses nested _meta" - input_schema({ properties: { message: { type: "string" } }, required: ["message"] }) - - class << self - def call(message:, server_context:) - user = server_context[:user] - session_id = server_context.dig(:_meta, :session_id) - Tool::Response.new([ - { type: "text", content: "User: #{user}, Session: #{session_id}, Message: #{message}" }, - ]) - end - end - end - - server = Server.new( - name: "test_server", - tools: [ToolWithNestedMeta], - server_context: { user: "test_user", original_field: "value" }, - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_nested_meta", - arguments: { message: "Hello" }, - _meta: { - session_id: "abc123", - }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "User: test_user, Session: abc123, Message: Hello", - response[:result][:content][0][:content] - end - - test "_meta preserves original server_context" do - class ToolPreservesContext < Tool - tool_name "tool_preserves_context" - description "A tool that checks context preservation" - - class << self - def call(server_context:) - priority = server_context[:priority] - meta_priority = server_context.dig(:_meta, :priority) - Tool::Response.new([ - { type: "text", content: "Context priority: #{priority}, Meta priority: #{meta_priority}" }, - ]) - end - end - end - - server = Server.new( - name: "test_server", - tools: [ToolPreservesContext], - server_context: { priority: "low" }, - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_preserves_context", - arguments: {}, - _meta: { - priority: "high", - }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "Context priority: low, Meta priority: high", response[:result][:content][0][:content] - end - - test "prompt receives _meta when provided in request params" do - class PromptWithMeta < Prompt - prompt_name "prompt_with_meta" - description "A prompt that uses _meta" - arguments [Prompt::Argument.new(name: "message", required: true)] - - class << self - def template(args, server_context:) - meta_info = server_context.dig(:_meta, :request_id) - Prompt::Result.new( - messages: [ - Prompt::Message.new( - role: "user", - content: Content::Text.new("Message: #{args[:message]}, Request ID: #{meta_info}"), - ), - ], - ) - end - end - end - - server = Server.new( - name: "test_server", - prompts: [PromptWithMeta], - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "prompts/get", - params: { - name: "prompt_with_meta", - arguments: { message: "Hello" }, - _meta: { - request_id: "req_12345", - }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "Message: Hello, Request ID: req_12345", - response[:result][:messages][0][:content][:text] - end - - test "non-Hash server_context is preserved when _meta is present" do - server_obj = Object.new - def server_obj.custom_method - "custom_value" - end - - tool_class = Class.new(Tool) do - tool_name "tool_with_non_hash_context" - - define_singleton_method(:call) do |server_context:, **_args| - Tool::Response.new([ - { type: "text", content: "custom: #{server_context.custom_method}" }, - ]) - end - end - - server = Server.new( - name: "test_server", - tools: [tool_class], - server_context: server_obj, - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_non_hash_context", - arguments: {}, - _meta: { progressToken: "token-1" }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "custom: custom_value", response[:result][:content][0][:content] - end - - test "_meta is nested within server_context for prompts" do - class PromptWithNestedContext < Prompt - prompt_name "prompt_with_nested_context" - description "A prompt that uses nested context" - arguments [Prompt::Argument.new(name: "message", required: true)] - - class << self - def template(args, server_context:) - user = server_context[:user] - trace_id = server_context.dig(:_meta, :trace_id) - Prompt::Result.new( - messages: [ - Prompt::Message.new( - role: "user", - content: Content::Text.new("User: #{user}, Trace: #{trace_id}, Message: #{args[:message]}"), - ), - ], - ) - end - end - end - - server = Server.new( - name: "test_server", - prompts: [PromptWithNestedContext], - server_context: { user: "prompt_user" }, - ) - - request = { - jsonrpc: "2.0", - id: 1, - method: "prompts/get", - params: { - name: "prompt_with_nested_context", - arguments: { message: "World" }, - _meta: { - trace_id: "trace_xyz789", - }, - }, - } - - response = server.handle(request) - - assert response[:result] - assert_equal "User: prompt_user, Trace: trace_xyz789, Message: World", - response[:result][:messages][0][:content][:text] - end - - private - - def build_modern_server_context(notification_target, log_level: nil) - envelope = RequestEnvelope.new( - protocol_version: "2026-07-28", - client_info: { name: "modern_client", version: "2.0" }, - client_capabilities: { elicitation: { form: {} } }, - log_level: log_level, - ) - progress = Progress.new(notification_target: notification_target, progress_token: nil) - ServerContext.new(nil, progress: progress, notification_target: notification_target, envelope: envelope) - end end end diff --git a/test/mcp/server_elicitation_test.rb b/test/mcp/server_elicitation_test.rb deleted file mode 100644 index 03f3609..0000000 --- a/test/mcp/server_elicitation_test.rb +++ /dev/null @@ -1,248 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerElicitationTest < ActiveSupport::TestCase - include InstrumentationTestHelper - - class MockTransport < Transport - attr_reader :requests, :notifications - - def initialize(server) - super - @requests = [] - @notifications = [] - end - - def send_request(method, params = nil, **_kwargs) - @requests << { method: method, params: params } - { action: "accept" } - end - - def send_response(response); end - - def send_notification(method, params = nil, **_kwargs) - @notifications << { method: method, params: params } - end - - def open; end - def close; end - def handle_request(request); end - end - - setup do - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - - @server = Server.new( - name: "test_server", - version: "1.0.0", - configuration: configuration, - ) - - @mock_transport = MockTransport.new(@server) - @server.transport = @mock_transport - - @session = ServerSession.new(server: @server, transport: @mock_transport) - @session.instance_variable_set(:@client_capabilities, { elicitation: {} }) - end - - test "#create_form_elicitation warns when called without related_request_id" do - # Per SEP-2260, server-to-client requests must be associated with an originating client request. - # `$VERBOSE = false` because the rake test task runs with `-W0`, under which `Kernel#warn` emits nothing. - original_verbose = $VERBOSE - $VERBOSE = false - - assert_output(nil, /SEP-2260/) do - @session.create_form_elicitation( - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - ) - end - ensure - $VERBOSE = original_verbose - end - - test "#create_url_elicitation warns when called without related_request_id" do - @session.instance_variable_set(:@client_capabilities, { elicitation: { url: true } }) - - original_verbose = $VERBOSE - $VERBOSE = false - - assert_output(nil, /SEP-2260/) do - @session.create_url_elicitation( - message: "Please sign in", - url: "https://example.com/signin", - elicitation_id: "el-1", - ) - end - ensure - $VERBOSE = original_verbose - end - - test "#create_form_elicitation does not warn when related_request_id is given" do - assert_silent do - @session.create_form_elicitation( - related_request_id: "req-1", - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - ) - end - end - - test "#create_form_elicitation sends request through transport" do - result = @session.create_form_elicitation( - related_request_id: "req-1", - message: "Please provide your name", - requested_schema: { - type: "object", - properties: { - name: { type: "string" }, - }, - required: ["name"], - }, - ) - - assert_equal 1, @mock_transport.requests.size - - request = @mock_transport.requests.first - - assert_equal Methods::ELICITATION_CREATE, request[:method] - assert_equal "form", request[:params][:mode] - assert_equal "Please provide your name", request[:params][:message] - assert_equal "object", request[:params][:requestedSchema][:type] - assert_equal({ action: "accept" }, result) - end - - test "#create_form_elicitation raises error when client does not support elicitation" do - @session.instance_variable_set(:@client_capabilities, {}) - - error = assert_raises(RuntimeError) do - @session.create_form_elicitation( - related_request_id: "req-1", - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - ) - end - - assert_equal( - "Client does not support elicitation. The client must declare the `elicitation` capability during initialization.", - error.message, - ) - end - - test "#create_form_elicitation raises error when client capabilities are nil" do - @session.instance_variable_set(:@client_capabilities, nil) - @server.instance_variable_set(:@client_capabilities, nil) - - error = assert_raises(RuntimeError) do - @session.create_form_elicitation( - related_request_id: "req-1", - message: "Please provide your name", - requested_schema: { type: "object", properties: { name: { type: "string" } } }, - ) - end - - assert_equal( - "Client does not support elicitation. The client must declare the `elicitation` capability during initialization.", - error.message, - ) - end - - test "#create_url_elicitation sends url mode request through transport" do - @session.instance_variable_set(:@client_capabilities, { elicitation: { url: {} } }) - - result = @session.create_url_elicitation( - related_request_id: "req-1", - message: "Please authorize access", - url: "https://example.com/oauth", - elicitation_id: "abc-123", - ) - - assert_equal 1, @mock_transport.requests.size - - request = @mock_transport.requests.first - - assert_equal Methods::ELICITATION_CREATE, request[:method] - assert_equal "url", request[:params][:mode] - assert_equal "Please authorize access", request[:params][:message] - assert_equal "https://example.com/oauth", request[:params][:url] - assert_equal "abc-123", request[:params][:elicitationId] - assert_equal({ action: "accept" }, result) - end - - test "#create_url_elicitation raises error when client does not support url mode" do - error = assert_raises(RuntimeError) do - @session.create_url_elicitation( - related_request_id: "req-1", - message: "Please authorize access", - url: "https://example.com/oauth", - elicitation_id: "abc-123", - ) - end - - assert_equal( - "Client does not support URL mode elicitation. The client must declare the `elicitation.url` capability during initialization.", - error.message, - ) - end - - test "#create_url_elicitation raises error when client capabilities are nil" do - @session.instance_variable_set(:@client_capabilities, nil) - @server.instance_variable_set(:@client_capabilities, nil) - - error = assert_raises(RuntimeError) do - @session.create_url_elicitation( - related_request_id: "req-1", - message: "Please authorize access", - url: "https://example.com/oauth", - elicitation_id: "abc-123", - ) - end - - assert_equal( - "Client does not support URL mode elicitation. The client must declare the `elicitation.url` capability during initialization.", - error.message, - ) - end - - test "#notify_elicitation_complete sends notification through transport" do - @session.notify_elicitation_complete(elicitation_id: "abc-123") - - assert_equal 1, @mock_transport.notifications.size - - notification = @mock_transport.notifications.first - - assert_equal Methods::NOTIFICATIONS_ELICITATION_COMPLETE, notification[:method] - assert_equal "abc-123", notification[:params][:elicitationId] - end - - test "URLElicitationRequiredError can be raised from a tool handler" do - @server.define_tool(name: "needs_auth", description: "Needs OAuth") do - raise Server::URLElicitationRequiredError, [ - { mode: "url", elicitationId: "abc-123", url: "https://example.com/oauth", message: "Auth required" }, - ] - end - - response = JSON.parse(@server.handle_json(JSON.generate({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "needs_auth", arguments: {} }, - }))) - - assert_equal(-32042, response["error"]["code"]) - assert_equal "URL elicitation required", response["error"]["message"] - - elicitations = response["error"]["data"]["elicitations"] - - assert_equal 1, elicitations.size - assert_equal "abc-123", elicitations.first["elicitationId"] - - assert_instrumentation_data( - method: "tools/call", tool_name: "needs_auth", tool_arguments: {}, error: :url_elicitation_required, - ) - end - end -end diff --git a/test/mcp/server_input_required_legacy_shim_test.rb b/test/mcp/server_input_required_legacy_shim_test.rb deleted file mode 100644 index ce0f4b4..0000000 --- a/test/mcp/server_input_required_legacy_shim_test.rb +++ /dev/null @@ -1,337 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - # The SEP-2322 dual-era authoring shim: a handler returning an `InputRequiredResult` - # on the legacy wire is fulfilled through real server-to-client requests and re-run, - # so handlers written in the 2026 style serve pre-2026 clients too. - class ServerInputRequiredLegacyShimTest < ActiveSupport::TestCase - # Answers every server-to-client request like a cooperative client and records what was sent. - class AnsweringTransport - attr_reader :sent - - def initialize(answers = {}) - @answers = answers - @sent = [] - end - - def send_request(method, params = nil, related_request_id: nil) - @sent << { method: method, params: params, related_request_id: related_request_id } - @answers.fetch(method) do - case method - when Methods::ELICITATION_CREATE - { action: "accept", content: { name: "Koichi" } } - when Methods::ROOTS_LIST - { roots: [{ uri: "file:///workspace", name: "workspace" }] } - when Methods::SAMPLING_CREATE_MESSAGE - { role: "assistant", content: { type: "text", text: "sampled" }, model: "test-model" } - end - end - end - - def send_notification(method, params = nil, session_id: nil, related_request_id: nil) - true - end - end - - # Raises like the bundled transports when the client answers a server-to-client request - # with a JSON-RPC error. - class RejectingTransport - def send_request(method, params = nil, related_request_id: nil) - raise StandardError, "Client returned an error for #{method} request (code: -1): User rejected" - end - - def send_notification(method, params = nil, session_id: nil, related_request_id: nil) - true - end - end - - setup do - @greeting_tool = Tool.define(name: "greeter") do |server_context:| - answer = server_context.input_response("who") - if answer - Tool::Response.new([{ type: "text", text: "Hello, #{answer.dig(:content, :name)}!" }]) - else - Server::InputRequiredResult.new( - input_requests: { "who" => { method: Methods::ELICITATION_CREATE, params: { message: "Who?" } } }, - request_state: "round-1", - ) - end - end - end - - test "a legacy tools/call is fulfilled through a real elicitation and completes" do - transport = AnsweringTransport.new - session = legacy_session(tools: [@greeting_tool], transport: transport) - - response = session.handle(tool_call_request) - - assert_equal "Hello, Koichi!", response.dig(:result, :content, 0, :text) - refute response[:result].key?(:resultType) - - sent = transport.sent.first - assert_equal Methods::ELICITATION_CREATE, sent[:method] - assert_equal({ message: "Who?" }, sent[:params]) - - # SEP-2260: the fulfilment request stays associated with the originating request. - assert_equal 1, sent[:related_request_id] - end - - test "the handler re-runs with the collected responses and the raw requestState" do - seen = [] - tool = Tool.define(name: "stateful") do |server_context:| - seen << { responses: server_context.input_responses, state: server_context.request_state } - if server_context.request_state == "opaque-state" - Tool::Response.new([{ type: "text", text: "resumed" }]) - else - Server::InputRequiredResult.new( - input_requests: { "k" => { method: Methods::ELICITATION_CREATE, params: { message: "?" } } }, - request_state: "opaque-state", - ) - end - end - session = legacy_session(tools: [tool], transport: AnsweringTransport.new) - - response = session.handle(tool_call_request(name: "stateful")) - - assert_equal "resumed", response.dig(:result, :content, 0, :text) - assert_equal 2, seen.size - assert_nil seen.first[:responses] - assert_equal "opaque-state", seen.last[:state] - assert_equal({ action: "accept", content: { name: "Koichi" } }, seen.last[:responses]["k"]) - end - - test "the shim bypasses requestState sealing" do - seen_state = nil - tool = Tool.define(name: "sealed") do |server_context:| - if server_context.request_state - seen_state = server_context.request_state - Tool::Response.new([{ type: "text", text: "done" }]) - else - Server::InputRequiredResult.new( - input_requests: { "k" => { method: Methods::ELICITATION_CREATE, params: { message: "?" } } }, - request_state: "plain-state", - ) - end - end - security = Server::RequestStateSecurity.new(key: "k" * 32) - session = legacy_session(tools: [tool], transport: AnsweringTransport.new, request_state_security: security) - - response = session.handle(tool_call_request(name: "sealed")) - - assert_equal "done", response.dig(:result, :content, 0, :text) - - # In-process replay round-trips the handler's own value; sealing is wire hardening. - assert_equal "plain-state", seen_state - end - - test "prompts/get and resources/read are shimmed too" do - prompt = Prompt.define(name: "greeting_prompt") do |_args, server_context:| - if server_context.input_response("who") - Prompt::Result.new(messages: [Prompt::Message.new(role: "user", content: Content::Text.new("hi"))]) - else - Server::InputRequiredResult.new( - input_requests: { "who" => { method: Methods::ELICITATION_CREATE, params: { message: "Who?" } } }, - ) - end - end - server = Server.new(name: "shim_test", prompts: [prompt], resources: []) - server.resources_read_handler do |params| - # `server_context` is unavailable in this handler shape, so park once via the params-visible retry fields instead. - if params[:inputResponses] - [{ uri: params[:uri], mimeType: "text/plain", text: "read" }] - else - Server::InputRequiredResult.new( - input_requests: { "who" => { method: Methods::ELICITATION_CREATE, params: { message: "Who?" } } }, - ) - end - end - transport = AnsweringTransport.new - session = ServerSession.new(server: server, transport: transport, session_id: "legacy") - session.store_client_info(client: { name: "legacy" }, capabilities: { elicitation: { form: {} } }) - - prompt_response = session.handle( - { jsonrpc: "2.0", id: 10, method: Methods::PROMPTS_GET, params: { name: "greeting_prompt" } }, - ) - assert_equal "hi", prompt_response.dig(:result, :messages, 0, :content, :text) - - read_response = session.handle( - { jsonrpc: "2.0", id: 11, method: Methods::RESOURCES_READ, params: { uri: "file:///a.txt" } }, - ) - assert_equal "read", read_response.dig(:result, :contents, 0, :text) - end - - test "multiple rounds collect each round's answers" do - rounds = [] - tool = Tool.define(name: "two_rounds") do |server_context:| - rounds << server_context.input_responses&.keys - if server_context.input_response("second") - Tool::Response.new([{ type: "text", text: "done" }]) - elsif server_context.input_response("first") - Server::InputRequiredResult.new( - input_requests: { "second" => { method: Methods::ELICITATION_CREATE, params: { message: "2?" } } }, - request_state: "after-first", - ) - else - Server::InputRequiredResult.new( - input_requests: { "first" => { method: Methods::ELICITATION_CREATE, params: { message: "1?" } } }, - ) - end - end - session = legacy_session(tools: [tool], transport: AnsweringTransport.new) - - response = session.handle(tool_call_request(name: "two_rounds")) - - assert_equal "done", response.dig(:result, :content, 0, :text) - assert_equal [nil, ["first"], ["second"]], rounds - end - - test "a url-mode elicitation leg gains the elicitationId the legacy wire requires" do - # The 2026-07-28 in-band shape has no `elicitationId` (correlation rides `requestState`), - # but the 2025-11-25 wire requires the field on URL-mode elicitation requests. - transport = AnsweringTransport.new - tool = Tool.define(name: "url_asker") do |server_context:| - if server_context.input_response("auth") - Tool::Response.new([{ type: "text", text: "authed" }]) - else - Server::InputRequiredResult.new( - input_requests: { - "auth" => { - method: Methods::ELICITATION_CREATE, - params: { mode: "url", url: "https://example.com/auth", message: "Sign in" }, - }, - }, - ) - end - end - session = legacy_session(tools: [tool], transport: transport, capabilities: { elicitation: { url: {} } }) - - response = session.handle(tool_call_request(name: "url_asker")) - - assert_equal "authed", response.dig(:result, :content, 0, :text) - sent = transport.sent.first - assert_equal "https://example.com/auth", sent[:params][:url] - refute_nil sent[:params][:elicitationId] - end - - test "a handler-supplied elicitationId rides the leg unchanged" do - transport = AnsweringTransport.new - tool = Tool.define(name: "url_asker") do |server_context:| - if server_context.input_response("auth") - Tool::Response.new([{ type: "text", text: "authed" }]) - else - Server::InputRequiredResult.new( - input_requests: { - "auth" => { - method: Methods::ELICITATION_CREATE, - params: { mode: "url", url: "https://example.com/auth", elicitationId: "mine" }, - }, - }, - ) - end - end - session = legacy_session(tools: [tool], transport: transport, capabilities: { elicitation: { url: {} } }) - - session.handle(tool_call_request(name: "url_asker")) - - assert_equal "mine", transport.sent.first[:params][:elicitationId] - end - - test "a client answering a fulfilment leg with an error fails the original request" do - session = legacy_session(tools: [@greeting_tool], transport: RejectingTransport.new) - - response = session.handle(tool_call_request) - - assert_equal(-32603, response.dig(:error, :code)) - end - - test "a handler that never completes fails after the round cap" do - tool = Tool.define(name: "greedy") do |server_context:| - round = (server_context.request_state || "0").to_i + 1 - Server::InputRequiredResult.new( - input_requests: { "k#{round}" => { method: Methods::ELICITATION_CREATE, params: { message: "?" } } }, - request_state: round.to_s, - ) - end - session = legacy_session(tools: [tool], transport: AnsweringTransport.new) - - response = session.handle(tool_call_request(name: "greedy")) - - assert_equal(-32603, response.dig(:error, :code)) - assert_match(/#{Server::LEGACY_INPUT_REQUIRED_MAX_ROUNDS} legacy shim rounds/, response.dig(:error, :message)) - end - - test "embedded requests exceeding the declared capabilities fail without contacting the client" do - transport = AnsweringTransport.new - session = legacy_session(tools: [@greeting_tool], transport: transport, capabilities: {}) - - response = session.handle(tool_call_request) - - assert_equal(-32603, response.dig(:error, :code)) - assert_match(/elicitation/, response.dig(:error, :message)) - assert_empty transport.sent - end - - test "opting out restores the strict legacy rejection" do - session = legacy_session( - tools: [@greeting_tool], - transport: AnsweringTransport.new, - input_required_legacy_shim: false, - ) - - response = session.handle(tool_call_request) - - assert_equal(-32603, response.dig(:error, :code)) - end - - test "a session-less legacy request is still rejected" do - server = Server.new(name: "shim_test", tools: [@greeting_tool]) - - response = server.handle(tool_call_request) - - assert_equal(-32603, response.dig(:error, :code)) - end - - test "modern requests keep the input_required result untouched" do - session = legacy_session(tools: [@greeting_tool], transport: transport = AnsweringTransport.new) - - response = session.handle({ - jsonrpc: "2.0", - id: 1, - method: Methods::TOOLS_CALL, - params: { - name: "greeter", - arguments: {}, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientInfo": { name: "modern", version: "1" }, - "io.modelcontextprotocol/clientCapabilities": { elicitation: { form: {} } }, - }, - }, - }) - - assert_equal "input_required", response.dig(:result, :resultType) - assert_empty transport.sent - end - - private - - def legacy_session(tools:, transport:, capabilities: { elicitation: { form: {} } }, - input_required_legacy_shim: true, request_state_security: nil) - server = Server.new( - name: "shim_test", - tools: tools, - input_required_legacy_shim: input_required_legacy_shim, - request_state_security: request_state_security, - ) - session = ServerSession.new(server: server, transport: transport, session_id: "legacy") - session.store_client_info(client: { name: "legacy" }, capabilities: capabilities) - session - end - - def tool_call_request(name: "greeter") - { jsonrpc: "2.0", id: 1, method: Methods::TOOLS_CALL, params: { name: name, arguments: {} } } - end - end -end diff --git a/test/mcp/server_notification_test.rb b/test/mcp/server_notification_test.rb index ffeb3a8..3b4ebf0 100644 --- a/test/mcp/server_notification_test.rb +++ b/test/mcp/server_notification_test.rb @@ -5,7 +5,6 @@ require "test_helper" module MCP class ServerNotificationTest < ActiveSupport::TestCase include InstrumentationTestHelper - include DeprecationWarningTestHelper class MockTransport < Transport attr_reader :notifications @@ -37,6 +36,7 @@ module MCP ) @mock_transport = MockTransport.new(@server) + @server.transport = @mock_transport end test "#notify_tools_list_changed sends notification through transport" do @@ -66,179 +66,36 @@ module MCP assert_nil notification[:params] end - test "#notify_log_message sends notification through transport" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - - assert_equal 1, @mock_transport.notifications.size - assert_equal Methods::NOTIFICATIONS_MESSAGE, @mock_transport.notifications.first[:method] - assert_equal({ "data" => { error: "Connection Failed" }, "level" => "error" }, @mock_transport.notifications.first[:params]) - end - - test "#notify_log_message does not warn when no protocol version has been established" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - - assert_no_deprecation_warning do - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - end - - assert_equal Methods::NOTIFICATIONS_MESSAGE, @mock_transport.notifications.first[:method] - end - - test "#notify_log_message does not warn on any server configuration" do - # A modern pin is rejected at configuration time and the handshake never lands on - # a deprecating revision, so no server-side path can reach the SEP-2577 warnings; - # the notification itself still goes out (or is suppressed below the configured level). - server = Server.new(name: "test_server", version: "1.0.0") - mock_transport = MockTransport.new(server) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - - assert_no_deprecation_warning do - server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - end - - assert_equal Methods::NOTIFICATIONS_MESSAGE, mock_transport.notifications.first[:method] - - assert_no_deprecation_warning do - server.notify_log_message(data: { message: "test" }, level: "info") - end - - assert_equal 1, mock_transport.notifications.size - end - - test "#notify_log_message does not warn when configured protocol version is older" do - server = Server.new( - name: "test_server", - version: "1.0.0", - configuration: Configuration.new(protocol_version: "2025-11-25"), - ) - MockTransport.new(server) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - - assert_no_deprecation_warning do - server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - end - end - - test "ServerSession#notify_log_message does not warn after a modern initialize request is counter-offered" do - # `initialize` asking for 2026-07-28 lands on 2025-11-25 (SEP-2575 era model), where logging - # is not deprecated; the below-configured-level suppression still applies. - server = Server.new(name: "test_server", version: "1.0.0") - mock_transport = MockTransport.new(server) - session = ServerSession.new(server: server, transport: mock_transport) - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2026-07-28", - capabilities: {}, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }, - session: session, - ) - session.configure_logging(MCP::LoggingMessageNotification.new(level: "error")) - - assert_no_deprecation_warning do - session.notify_log_message(data: { message: "test" }, level: "info") - end - - assert_empty mock_transport.notifications - end - - test "ServerSession#notify_log_message on a modern-era session ignores the server-wide level" do - # SEP-2575: on the modern lifecycle, log delivery is authorized per request via - # the envelope's logLevel; the server-wide level MUST NOT apply. - server = Server.new(name: "test_server", version: "1.0.0") - mock_transport = MockTransport.new(server) - server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "debug") - session = ServerSession.new(server: server, transport: mock_transport, era: :modern) - - session.notify_log_message(data: { message: "test" }, level: "error") - - assert_empty mock_transport.notifications - end - - test "ServerSession#notify_log_message on a modern-era session honors a per-request level" do - server = Server.new(name: "test_server", version: "1.0.0") - mock_transport = MockTransport.new(server) - session = ServerSession.new(server: server, transport: mock_transport, era: :modern) - session.configure_logging(MCP::LoggingMessageNotification.new(level: "info")) - - session.notify_log_message(data: { message: "test" }, level: "error") - - assert_equal 1, mock_transport.notifications.length - assert_equal Methods::NOTIFICATIONS_MESSAGE, mock_transport.notifications.first[:method] - end - - test "#notify_log_message sends notification with logger through transport" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error", logger: "DatabaseLogger") - - assert_equal 1, @mock_transport.notifications.size - notification = @mock_transport.notifications.first - assert_equal Methods::NOTIFICATIONS_MESSAGE, notification[:method] - assert_equal({ "data" => { error: "Connection Failed" }, "level" => "error", "logger" => "DatabaseLogger" }, notification[:params]) - end - - test "#notify_log_message does not send notification with invalid log level" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { message: "test" }, level: "invalid") - - assert_equal 0, @mock_transport.notifications.size - end - - test "#notify_log_message does not send notification when level is below configured level" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { message: "test" }, level: "info") - - assert_equal 0, @mock_transport.notifications.size - end - - test "#notify_log_message sends notification when level is above configured level through transport" do - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { message: "test" }, level: "critical") - - assert_equal 1, @mock_transport.notifications.size - assert_equal Methods::NOTIFICATIONS_MESSAGE, @mock_transport.notifications[0][:method] - assert_equal({ "data" => { message: "test" }, "level" => "critical" }, @mock_transport.notifications[0][:params]) - end - test "notification methods work without transport" do server_without_transport = Server.new(name: "test_server") - server_without_transport.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") # Should not raise any errors assert_nothing_raised do server_without_transport.notify_tools_list_changed server_without_transport.notify_prompts_list_changed server_without_transport.notify_resources_list_changed - server_without_transport.notify_log_message(data: { error: "Connection Failed" }, level: "error") end end test "notification methods handle transport errors gracefully" do - # Replace server's transport with one that raises on send_notification. - Class.new(MockTransport) do + # Create a transport that raises errors + error_transport = Class.new(MockTransport) do def send_notification(method, params = nil) raise StandardError, "Transport error" end end.new(@server) - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") + @server.transport = error_transport # Mock the exception reporter expected_contexts = [ { notification: "tools_list_changed" }, { notification: "prompts_list_changed" }, { notification: "resources_list_changed" }, - { notification: "log_message" }, ] call_count = 0 - @server.configuration.exception_reporter.expects(:call).times(4).with do |exception, context| + @server.configuration.exception_reporter.expects(:call).times(3).with do |exception, context| assert_kind_of StandardError, exception assert_equal "Transport error", exception.message assert_includes expected_contexts, context @@ -251,44 +108,22 @@ module MCP @server.notify_tools_list_changed @server.notify_prompts_list_changed @server.notify_resources_list_changed - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") end - assert_equal 4, call_count + assert_equal 3, call_count end test "multiple notification methods can be called in sequence" do @server.notify_tools_list_changed @server.notify_prompts_list_changed @server.notify_resources_list_changed - @server.logging_message_notification = MCP::LoggingMessageNotification.new(level: "error") - @server.notify_log_message(data: { error: "Connection Failed" }, level: "error") - assert_equal 4, @mock_transport.notifications.size + assert_equal 3, @mock_transport.notifications.size notifications = @mock_transport.notifications assert_equal Methods::NOTIFICATIONS_TOOLS_LIST_CHANGED, notifications[0][:method] assert_equal Methods::NOTIFICATIONS_PROMPTS_LIST_CHANGED, notifications[1][:method] assert_equal Methods::NOTIFICATIONS_RESOURCES_LIST_CHANGED, notifications[2][:method] - assert_equal Methods::NOTIFICATIONS_MESSAGE, notifications[3][:method] - end - - test "server.notify_log_message works after logging/setLevel via session" do - session = ServerSession.new(server: @server, transport: @mock_transport) - - # Client sends logging/setLevel through session. - @server.handle( - { jsonrpc: "2.0", id: 1, method: "logging/setLevel", params: { level: "info" } }, - session: session, - ) - - # Server-level broadcast should still work because logging level - # is stored on both the session and the server. - @server.notify_log_message(data: "broadcast log", level: "info") - - log_notifications = @mock_transport.notifications.select { |n| n[:method] == Methods::NOTIFICATIONS_MESSAGE } - assert_equal 1, log_notifications.size - assert_equal "broadcast log", log_notifications.first[:params]["data"] end end end diff --git a/test/mcp/server_progress_test.rb b/test/mcp/server_progress_test.rb deleted file mode 100644 index e13fde5..0000000 --- a/test/mcp/server_progress_test.rb +++ /dev/null @@ -1,317 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerProgressTest < ActiveSupport::TestCase - class MockTransport < Transport - attr_reader :notifications - - def initialize(server) - super - @notifications = [] - end - - def send_notification(method, params = nil) - @notifications << { method: method, params: params } - true - end - - def send_response(response); end - def open; end - def close; end - def handle_request(request); end - end - - # Tool without progress parameter. - class SimpleToolWithoutProgress < Tool - tool_name "simple_without_progress" - description "A tool that doesn't use progress" - input_schema(properties: { message: { type: "string" } }, required: ["message"]) - - class << self - def call(message:) - Tool::Response.new([{ type: "text", text: "SimpleToolWithoutProgress: #{message}" }]) - end - end - end - - # Tool with progress via server_context. - class ToolWithProgress < Tool - tool_name "tool_with_progress" - description "A tool that uses progress" - input_schema(properties: { message: { type: "string" } }, required: ["message"]) - - class << self - def call(message:, server_context:) - server_context.report_progress(50, total: 100, message: "halfway") - server_context.report_progress(100, total: 100, message: "done") - Tool::Response.new([{ type: "text", text: "ToolWithProgress: #{message}" }]) - end - end - end - - # Tool with server_context accessing both context data and progress. - class ToolWithContextAndProgress < Tool - tool_name "tool_with_context_and_progress" - description "A tool that uses both server_context and progress" - input_schema(properties: { message: { type: "string" } }, required: ["message"]) - - class << self - def call(message:, server_context:) - server_context.report_progress(100) - context_info = server_context[:user] || "none" - Tool::Response.new([{ type: "text", text: "ToolWithContextAndProgress: #{message} context=#{context_info}" }]) - end - end - end - - # Tool with **kwargs. - class ToolWithKwargs < Tool - tool_name "tool_with_kwargs" - description "A tool that uses **kwargs" - - class << self - def call(**kwargs) - context = kwargs[:server_context] - context.report_progress(75) - Tool::Response.new([{ type: "text", text: "ToolWithKwargs: progress=#{context ? "present" : "absent"}" }]) - end - end - end - - setup do - @server = Server.new( - name: "test_server", - version: "1.0.0", - tools: [SimpleToolWithoutProgress, ToolWithProgress, ToolWithContextAndProgress, ToolWithKwargs], - server_context: { user: "test_user" }, - ) - - @mock_transport = MockTransport.new(@server) - @session = ServerSession.new(server: @server, transport: @mock_transport) - end - - test "tool with progress parameter receives Progress instance and sends notifications via _meta.progressToken" do - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_progress", - arguments: { message: "Hello" }, - _meta: { progressToken: "token-abc" }, - }, - } - - response = @session.handle(request) - - assert response[:result] - assert_equal "ToolWithProgress: Hello", response[:result][:content][0][:text] - - assert_equal 2, @mock_transport.notifications.size - - first = @mock_transport.notifications[0] - assert_equal Methods::NOTIFICATIONS_PROGRESS, first[:method] - assert_equal "token-abc", first[:params]["progressToken"] - assert_equal 50, first[:params]["progress"] - assert_equal 100, first[:params]["total"] - assert_equal "halfway", first[:params]["message"] - - second = @mock_transport.notifications[1] - assert_equal Methods::NOTIFICATIONS_PROGRESS, second[:method] - assert_equal "token-abc", second[:params]["progressToken"] - assert_equal 100, second[:params]["progress"] - assert_equal 100, second[:params]["total"] - assert_equal "done", second[:params]["message"] - end - - test "tool without progress parameter works normally" do - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "simple_without_progress", - arguments: { message: "Hello" }, - }, - } - - response = @session.handle(request) - - assert response[:result] - assert_equal "SimpleToolWithoutProgress: Hello", response[:result][:content][0][:text] - assert_equal 0, @mock_transport.notifications.size - end - - test "server_context.report_progress is a no-op when no progressToken in request" do - received_context = :unset - - tool_class = Class.new(Tool) do - tool_name "progress_nil_tool" - - define_singleton_method(:call) do |server_context:| - received_context = server_context - Tool::Response.new([{ type: "text", text: "done" }]) - end - end - - server = Server.new( - name: "test_server", - tools: [tool_class], - server_context: { user: "test" }, - ) - server.transport = @mock_transport - session = ServerSession.new(server: server, transport: @mock_transport) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "progress_nil_tool", - arguments: {}, - }, - } - - session.handle(request) - - assert_instance_of ServerContext, received_context - assert_nothing_raised { received_context.report_progress(50) } - assert_equal 0, @mock_transport.notifications.size - end - - test "tool with both server_context and progress receives both" do - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_context_and_progress", - arguments: { message: "Hello" }, - _meta: { progressToken: "token-xyz" }, - }, - } - - response = @session.handle(request) - - assert response[:result] - assert_equal "ToolWithContextAndProgress: Hello context=test_user", response[:result][:content][0][:text] - - assert_equal 1, @mock_transport.notifications.size - notification = @mock_transport.notifications.first - assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method] - assert_equal "token-xyz", notification[:params]["progressToken"] - assert_equal 100, notification[:params]["progress"] - end - - test "tool with **kwargs receives Progress instance" do - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "tool_with_kwargs", - arguments: {}, - _meta: { progressToken: "token-kwargs" }, - }, - } - - response = @session.handle(request) - - assert response[:result] - assert_equal "ToolWithKwargs: progress=present", response[:result][:content][0][:text] - - assert_equal 1, @mock_transport.notifications.size - notification = @mock_transport.notifications.first - assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method] - assert_equal "token-kwargs", notification[:params]["progressToken"] - assert_equal 75, notification[:params]["progress"] - end - - test "block-defined tool with progress via server_context works" do - server = Server.new(name: "test_server") - server.transport = @mock_transport - - server.define_tool(name: "block_tool") do |server_context:| - server_context.report_progress(42, total: 100) - Tool::Response.new([{ type: "text", text: "block_tool done" }]) - end - - session = ServerSession.new(server: server, transport: @mock_transport) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "block_tool", - arguments: {}, - _meta: { progressToken: "block-token" }, - }, - } - - response = session.handle(request) - - assert response[:result] - assert_equal "block_tool done", response[:result][:content][0][:text] - - assert_equal 1, @mock_transport.notifications.size - notification = @mock_transport.notifications.first - assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method] - assert_equal "block-token", notification[:params]["progressToken"] - assert_equal 42, notification[:params]["progress"] - assert_equal 100, notification[:params]["total"] - end - - test "multiple progress notifications during tool execution" do - server = Server.new(name: "test_server") - server.transport = @mock_transport - - server.define_tool(name: "multi_progress_tool") do |server_context:| - (1..5).each do |i| - server_context.report_progress(i * 20, total: 100) - end - Tool::Response.new([{ type: "text", text: "done" }]) - end - - session = ServerSession.new(server: server, transport: @mock_transport) - - request = { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "multi_progress_tool", - arguments: {}, - _meta: { progressToken: "multi-token" }, - }, - } - - session.handle(request) - - assert_equal 5, @mock_transport.notifications.size - @mock_transport.notifications.each_with_index do |n, i| - assert_equal Methods::NOTIFICATIONS_PROGRESS, n[:method] - assert_equal "multi-token", n[:params]["progressToken"] - assert_equal (i + 1) * 20, n[:params]["progress"] - assert_equal 100, n[:params]["total"] - end - end - - test "incoming notifications/progress is handled as no-op" do - request = { - jsonrpc: "2.0", - method: "notifications/progress", - params: { - progressToken: "token-1", - progress: 50, - }, - } - - # Should not raise and should return nil (notification, no id). - result = @session.handle(request) - assert_nil result - end - end -end diff --git a/test/mcp/server_roots_test.rb b/test/mcp/server_roots_test.rb deleted file mode 100644 index 39c4e8f..0000000 --- a/test/mcp/server_roots_test.rb +++ /dev/null @@ -1,301 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerRootsTest < ActiveSupport::TestCase - include DeprecationWarningTestHelper - - class MockTransport < Transport - attr_reader :requests - - def initialize(server) - super - @requests = [] - end - - def send_request(method, params = nil) - @requests << { method: method, params: params } - { - roots: [ - { uri: "file:///home/user/projects/myproject", name: "My Project" }, - ], - } - end - - def send_response(response); end - def send_notification(method, params = nil); end - def open; end - def close; end - end - - setup do - @server = Server.new( - name: "test_server", - version: "1.0.0", - ) - - @mock_transport = MockTransport.new(@server) - - @server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { roots: { listChanged: true } }, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }) - end - - test "roots_list_changed_handler registers callback invoked when notification received" do - callback_called = false - - @server.roots_list_changed_handler do |_params| - callback_called = true - end - - @server.handle({ - jsonrpc: "2.0", - method: "notifications/roots/list_changed", - }) - - assert callback_called - end - - test "notifications/roots/list_changed does not warn after a modern initialize request is counter-offered" do - # `initialize` asking for 2026-07-28 lands on 2025-11-25 (SEP-2575 era model), - # where roots is not deprecated. - server = Server.new(name: "test", version: "1.0") - server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2026-07-28", - capabilities: { roots: { listChanged: true } }, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }) - - assert_no_deprecation_warning do - server.handle({ - jsonrpc: "2.0", - method: "notifications/roots/list_changed", - }) - end - end - - test "notifications/roots/list_changed does not warn when negotiated protocol version is older" do - assert_no_deprecation_warning do - @server.handle({ - jsonrpc: "2.0", - method: "notifications/roots/list_changed", - }) - end - end - - test "notifications/roots/list_changed is handled as no-op by default" do - result = @server.handle({ - jsonrpc: "2.0", - method: "notifications/roots/list_changed", - }) - - assert_nil result - end - - test "init stores client capabilities" do - server = Server.new(name: "test", version: "1.0") - server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { roots: { listChanged: true } }, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }) - - assert_equal({ roots: { listChanged: true } }, server.client_capabilities) - end - - test "init rejects params without capabilities and stores nothing" do - server = Server.new(name: "test", version: "1.0") - response = server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - clientInfo: { name: "test-client", version: "1.0" }, - }, - }) - - assert_equal(-32602, response[:error][:code]) - assert_nil server.client_capabilities - end - - test "list_roots uses per-session capabilities via ServerSession" do - transport = MCP::Server::Transports::StreamableHTTPTransport.new(@server) - - session_with_roots = ServerSession.new(server: @server, transport: transport, session_id: "s1") - session_with_roots.store_client_info(client: { name: "capable" }, capabilities: { roots: {} }) - transport.instance_variable_get(:@sessions)["s1"] = { stream: nil, server_session: session_with_roots } - - error_with_roots = assert_raises(RuntimeError) do - capture_io { session_with_roots.list_roots } - end - assert_equal("No active stream for roots/list request.", error_with_roots.message) - - session_without_roots = ServerSession.new(server: @server, transport: transport, session_id: "s2") - session_without_roots.store_client_info(client: { name: "incapable" }, capabilities: {}) - - error = assert_raises(RuntimeError) do - capture_io { session_without_roots.list_roots } - end - assert_equal("Client does not support roots.", error.message) - end - - test "ServerSession#list_roots warns when called without related_request_id" do - # Per SEP-2260, server-to-client requests must be associated with an originating client request. - # `$VERBOSE = false` because the rake test task runs with `-W0`, under which `Kernel#warn` emits nothing. - session = ServerSession.new(server: @server, transport: @mock_transport) - session.store_client_info(client: { name: "capable" }, capabilities: { roots: {} }) - - original_verbose = $VERBOSE - $VERBOSE = false - assert_output(nil, /SEP-2260/) { session.list_roots } - ensure - $VERBOSE = original_verbose - end - - test "ServerSession#list_roots does not warn when related_request_id is given" do - session = ServerSession.new(server: @server, transport: @mock_transport) - session.store_client_info(client: { name: "capable" }, capabilities: { roots: {} }) - - assert_silent { session.list_roots(related_request_id: "req-1") } - end - - test "ServerSession#list_roots raises without a warning when the client lacks roots" do - # A modern pin is rejected at configuration time and the handshake never lands on - # a deprecating revision, so no server-side path can reach the SEP-2577 warnings. - session = ServerSession.new(server: @server, transport: @mock_transport, era: :modern) - session.store_client_info(client: { name: "test-client" }, capabilities: {}) - - error = nil - assert_no_deprecation_warning do - error = assert_raises(RuntimeError) do - session.list_roots(related_request_id: "req-1") - end - end - - assert_equal("Client does not support roots.", error.message) - end - - test "ServerSession#client_capabilities falls back to server global capabilities" do - transport = MCP::Server::Transports::StreamableHTTPTransport.new(@server) - - session = ServerSession.new(server: @server, transport: transport, session_id: "s3") - transport.instance_variable_get(:@sessions)["s3"] = { stream: nil, server_session: session } - - error = assert_raises(RuntimeError) do - capture_io { session.list_roots } - end - assert_equal("No active stream for roots/list request.", error.message) - end - - test "session init does not overwrite server global client_capabilities" do - server = Server.new(name: "test", version: "1.0") - MockTransport.new(server) - - server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { roots: {} }, - clientInfo: { name: "first-client", version: "1.0" }, - }, - }) - - assert_equal({ roots: {} }, server.client_capabilities) - - transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - session = ServerSession.new(server: server, transport: transport, session_id: "s1") - - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 2, - params: { - protocolVersion: "2025-11-25", - capabilities: {}, - clientInfo: { name: "second-client", version: "1.0" }, - }, - }, - session: session, - ) - - assert_equal({ roots: {} }, server.client_capabilities) - assert_equal({}, session.client_capabilities) - end - - test "ServerSession#list_roots uses session-scoped capabilities from HTTP init" do - server = Server.new(name: "test", version: "1.0") - transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - - session = ServerSession.new(server: server, transport: transport, session_id: "s1") - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { roots: {} }, - clientInfo: { name: "http-client", version: "1.0" }, - }, - }, - session: session, - ) - - transport.instance_variable_get(:@sessions)["s1"] = { stream: nil, server_session: session } - error = assert_raises(RuntimeError) do - capture_io { session.list_roots } - end - assert_equal("No active stream for roots/list request.", error.message) - end - - test "ServerSession#list_roots does not warn after a modern initialize request is counter-offered" do - # `initialize` asking for 2026-07-28 lands on 2025-11-25 (SEP-2575 era model), - # where roots is not deprecated; the request itself still goes out. - server = Server.new(name: "test", version: "1.0") - transport = MockTransport.new(server) - - session = ServerSession.new(server: server, transport: transport, session_id: "s1") - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2026-07-28", - capabilities: { roots: {} }, - clientInfo: { name: "http-client", version: "1.0" }, - }, - }, - session: session, - ) - - assert_no_deprecation_warning do - session.list_roots(related_request_id: "req-1") - end - - assert_equal Methods::ROOTS_LIST, transport.requests.first[:method] - end - end -end diff --git a/test/mcp/server_sampling_test.rb b/test/mcp/server_sampling_test.rb deleted file mode 100644 index c5d0d59..0000000 --- a/test/mcp/server_sampling_test.rb +++ /dev/null @@ -1,327 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerSamplingTest < ActiveSupport::TestCase - include InstrumentationTestHelper - include DeprecationWarningTestHelper - - class MockTransport < Transport - attr_reader :requests - - def initialize(server) - super - @requests = [] - end - - def send_request(method, params = nil, **_kwargs) - @requests << { method: method, params: params } - { - role: "assistant", - content: { type: "text", text: "Response from LLM" }, - model: "test-model", - stopReason: "endTurn", - } - end - - def send_response(response); end - def send_notification(method, params = nil, **_kwargs); end - def open; end - def close; end - end - - setup do - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - - @server = Server.new( - name: "test_server", - version: "1.0.0", - configuration: configuration, - ) - - @mock_transport = MockTransport.new(@server) - - @session = ServerSession.new(server: @server, transport: @mock_transport) - @session.store_client_info(client: { name: "test-client" }, capabilities: { sampling: {} }) - end - - test "create_sampling_message sends request with required params" do - result = @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - - assert_equal 1, @mock_transport.requests.size - request = @mock_transport.requests.first - assert_equal Methods::SAMPLING_CREATE_MESSAGE, request[:method] - assert_equal 100, request[:params][:maxTokens] - assert_equal [{ role: "user", content: { type: "text", text: "Hello" } }], request[:params][:messages] - - assert_equal "assistant", result[:role] - assert_equal "Response from LLM", result[:content][:text] - end - - test "create_sampling_message does not warn on a modern-era session" do - # A modern pin is rejected at configuration time and the handshake never lands on - # a deprecating revision, so no server-side path can reach the SEP-2577 warnings. - session = ServerSession.new(server: @server, transport: @mock_transport, era: :modern) - session.store_client_info(client: { name: "test-client" }, capabilities: { sampling: {} }) - - assert_no_deprecation_warning do - session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - - test "create_sampling_message does not warn when session negotiated protocol version is older" do - @session.mark_initialized!(protocol_version: "2025-11-25") - - assert_no_deprecation_warning do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - - test "create_sampling_message sends all optional params" do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - system_prompt: "You are helpful", - model_preferences: { intelligencePriority: 0.8 }, - include_context: "none", - temperature: 0.7, - stop_sequences: ["STOP"], - metadata: { key: "value" }, - ) - - request = @mock_transport.requests.first - params = request[:params] - - assert_equal "You are helpful", params[:systemPrompt] - assert_equal({ intelligencePriority: 0.8 }, params[:modelPreferences]) - assert_equal "none", params[:includeContext] - assert_equal 0.7, params[:temperature] - assert_equal ["STOP"], params[:stopSequences] - assert_equal({ key: "value" }, params[:metadata]) - end - - test "create_sampling_message raises error when client does not support sampling" do - @session.store_client_info(client: { name: "test-client" }, capabilities: {}) - - error = assert_raises(RuntimeError) do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - - assert_equal("Client does not support sampling.", error.message) - end - - test "create_sampling_message raises error when tools used but client lacks sampling.tools" do - error = assert_raises(RuntimeError) do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - tools: [{ name: "test_tool", inputSchema: { type: "object" } }], - ) - end - - assert_equal("Client does not support sampling with tools.", error.message) - end - - test "create_sampling_message raises error when tool_choice used alone but client lacks sampling.tools" do - error = assert_raises(RuntimeError) do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - tool_choice: { mode: "auto" }, - ) - end - - assert_equal("Client does not support sampling with tool_choice.", error.message) - end - - test "create_sampling_message allows tools when client has sampling.tools capability" do - @session.store_client_info(client: { name: "test-client" }, capabilities: { sampling: { tools: {} } }) - - result = @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - tools: [{ name: "test_tool", inputSchema: { type: "object" } }], - tool_choice: { mode: "auto" }, - ) - - request = @mock_transport.requests.first - params = request[:params] - - assert_equal [{ name: "test_tool", inputSchema: { type: "object" } }], params[:tools] - assert_equal({ mode: "auto" }, params[:toolChoice]) - assert_equal "Response from LLM", result[:content][:text] - end - - test "create_sampling_message warns when called without related_request_id" do - # Per SEP-2260, server-to-client requests must be associated with an originating client request. - # `$VERBOSE = false` because the rake test task runs with `-W0`, under which `Kernel#warn` emits nothing. - original_verbose = $VERBOSE - $VERBOSE = false - assert_output(nil, /SEP-2260/) do - @session.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - ensure - $VERBOSE = original_verbose - end - - test "create_sampling_message does not warn when related_request_id is given" do - assert_silent do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - - test "create_sampling_message uses per-session capabilities via ServerSession" do - transport = MCP::Server::Transports::StreamableHTTPTransport.new(@server) - - # Session with sampling capability passes validation (fails at send_request due to no stream). - session_with_sampling = ServerSession.new(server: @server, transport: transport, session_id: "s1") - session_with_sampling.store_client_info(client: { name: "capable" }, capabilities: { sampling: {} }) - transport.instance_variable_get(:@sessions)["s1"] = { stream: nil, server_session: session_with_sampling } - - error_with_sampling = assert_raises(RuntimeError) do - capture_io do - session_with_sampling.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - assert_equal("No active stream for sampling/createMessage request.", error_with_sampling.message) - - # Session without sampling capability should be rejected. - session_without_sampling = ServerSession.new(server: @server, transport: transport, session_id: "s2") - session_without_sampling.store_client_info(client: { name: "incapable" }, capabilities: {}) - - error = assert_raises(RuntimeError) do - capture_io do - session_without_sampling.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - assert_equal("Client does not support sampling.", error.message) - end - - test "ServerSession#client_capabilities falls back to server global capabilities" do - transport = MCP::Server::Transports::StreamableHTTPTransport.new(@server) - - # Initialize server with sampling capability. - @server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { sampling: {} }, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }) - - # Session without capabilities stored falls back to @server.client_capabilities. - session = ServerSession.new(server: @server, transport: transport, session_id: "s3") - transport.instance_variable_get(:@sessions)["s3"] = { stream: nil, server_session: session } - - # Server was initialized with sampling capability, so fallback should pass validation. - error = assert_raises(RuntimeError) do - capture_io do - session.create_sampling_message( - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - end - end - assert_equal("No active stream for sampling/createMessage request.", error.message) - end - - test "session init does not overwrite server global client_capabilities" do - server = Server.new(name: "test", version: "1.0") - # Assigns server.transport via Transport#initialize. - MockTransport.new(server) - - # Non-session init sets global capabilities. - server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: { sampling: {} }, - clientInfo: { name: "first-client", version: "1.0" }, - }, - }) - - assert_equal({ sampling: {} }, server.client_capabilities) - - # Session-scoped init must NOT overwrite global capabilities. - transport = MCP::Server::Transports::StreamableHTTPTransport.new(server) - session = ServerSession.new(server: server, transport: transport, session_id: "s1") - - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 2, - params: { - protocolVersion: "2025-11-25", - capabilities: {}, - clientInfo: { name: "second-client", version: "1.0" }, - }, - }, - session: session, - ) - - # Global must still have sampling. - assert_equal({ sampling: {} }, server.client_capabilities) - # Session must have its own (empty) capabilities. - assert_equal({}, session.client_capabilities) - end - - test "create_sampling_message omits nil optional params" do - @session.create_sampling_message( - related_request_id: "req-1", - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - system_prompt: nil, - temperature: nil, - ) - - request = @mock_transport.requests.first - params = request[:params] - - refute params.key?(:systemPrompt) - refute params.key?(:temperature) - assert params.key?(:messages) - assert params.key?(:maxTokens) - end - end -end diff --git a/test/mcp/server_session_ping_test.rb b/test/mcp/server_session_ping_test.rb deleted file mode 100644 index b467d3e..0000000 --- a/test/mcp/server_session_ping_test.rb +++ /dev/null @@ -1,93 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class ServerSessionPingTest < ActiveSupport::TestCase - class MockTransport < Transport - attr_reader :requests - attr_accessor :response, :error_to_raise - - def initialize(server) - super - @requests = [] - @response = {} - @error_to_raise = nil - end - - # Matches real transports: returns the `result` body directly (not the full envelope). - def send_request(method, params = nil, session_id: nil, related_request_id: nil) - @requests << { method: method, params: params, session_id: session_id, related_request_id: related_request_id } - raise @error_to_raise if @error_to_raise - - @response - end - - def send_response(response); end - def send_notification(method, params = nil); end - def open; end - def close; end - def handle_request(request); end - end - - setup do - @server = Server.new(name: "test_server", version: "1.0.0") - @mock_transport = MockTransport.new(@server) - @server.transport = @mock_transport - end - - test "#ping sends request through transport and returns the result hash" do - session = ServerSession.new(server: @server, transport: @mock_transport) - - result = session.ping - - assert_equal({}, result) - assert_equal(1, @mock_transport.requests.size) - - request = @mock_transport.requests.first - assert_equal(Methods::PING, request[:method]) - assert_nil(request[:params]) - end - - test "#ping passes related_request_id through when session_id is set" do - session = ServerSession.new(server: @server, transport: @mock_transport, session_id: "session-1") - - session.ping(related_request_id: "req-abc") - - request = @mock_transport.requests.first - assert_equal("session-1", request[:session_id]) - assert_equal("req-abc", request[:related_request_id]) - end - - test "#ping raises ValidationError when result is nil" do - @mock_transport.response = nil - session = ServerSession.new(server: @server, transport: @mock_transport) - - error = assert_raises(Server::ValidationError) { session.ping } - assert_equal("Response validation failed: invalid `result`", error.message) - end - - test "#ping raises ValidationError when result is the wrong type" do - @mock_transport.response = "ok" - session = ServerSession.new(server: @server, transport: @mock_transport) - - error = assert_raises(Server::ValidationError) { session.ping } - assert_equal("Response validation failed: invalid `result`", error.message) - end - - test "#ping propagates transport-level errors" do - @mock_transport.error_to_raise = StandardError.new("read timeout") - session = ServerSession.new(server: @server, transport: @mock_transport) - - error = assert_raises(StandardError) { session.ping } - assert_equal("read timeout", error.message) - end - - test "#ping succeeds without a client capability declaration" do - session = ServerSession.new(server: @server, transport: @mock_transport) - assert_nil(session.client_capabilities) - - assert_equal({}, session.ping) - end - end -end diff --git a/test/mcp/server_session_request_timeout_test.rb b/test/mcp/server_session_request_timeout_test.rb deleted file mode 100644 index f3ef1e6..0000000 --- a/test/mcp/server_session_request_timeout_test.rb +++ /dev/null @@ -1,99 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - # Every server-to-client request accepts a per-request deadline, which the spec asks SDKs to offer - # ("SDKs and other middleware SHOULD allow these timeouts to be configured on a per-request basis"). - # `ServerSession` only carries the value; the transport is what waits on it. - class ServerSessionRequestTimeoutTest < ActiveSupport::TestCase - # Declares `timeout:`, as the bundled Streamable HTTP transport does. - class TimeoutAwareTransport < Transport - attr_reader :requests - - def initialize(server) - super - @requests = [] - end - - def send_request(method, params = nil, session_id: nil, related_request_id: nil, parent_cancellation: nil, server_session: nil, timeout: nil) - @requests << { method: method, timeout: timeout } - {} - end - - def send_response(response); end - def send_notification(method, params = nil, **_kwargs); end - def open; end - def close; end - def handle_request(request); end - end - - # Implements only the abstract `send_request(method, params = nil)` contract, as `StdioTransport` does. - class TimeoutUnawareTransport < TimeoutAwareTransport - def send_request(method, params = nil) - @requests << { method: method, timeout: :not_passed } - {} - end - end - - setup do - @server = Server.new(name: "test_server", version: "1.0.0") - @transport = TimeoutAwareTransport.new(@server) - @session = ServerSession.new(server: @server, transport: @transport, session_id: "session-1") - @session.instance_variable_set( - :@client_capabilities, - { roots: {}, sampling: {}, elicitation: { url: {} } }, - ) - end - - test "every server-to-client request carries its timeout down to the transport" do - @session.ping(related_request_id: "req-1", timeout: 11) - @session.list_roots(related_request_id: "req-1", timeout: 22) - @session.create_sampling_message( - related_request_id: "req-1", - timeout: 33, - messages: [{ role: "user", content: { type: "text", text: "Hello" } }], - max_tokens: 100, - ) - @session.create_form_elicitation( - message: "Approve?", - requested_schema: { type: "object", properties: {} }, - related_request_id: "req-1", - timeout: 44, - ) - @session.create_url_elicitation( - message: "Approve?", - url: "https://example.com/approve", - elicitation_id: "elicit-1", - related_request_id: "req-1", - timeout: 55, - ) - - assert_equal( - [ - { method: "ping", timeout: 11 }, - { method: "roots/list", timeout: 22 }, - { method: "sampling/createMessage", timeout: 33 }, - { method: "elicitation/create", timeout: 44 }, - { method: "elicitation/create", timeout: 55 }, - ], - @transport.requests, - ) - end - - test "an omitted timeout leaves the transport to apply its own default" do - @session.ping(related_request_id: "req-1") - - assert_equal [{ method: "ping", timeout: nil }], @transport.requests - end - - test "a transport that does not declare timeout keeps its existing signature" do - transport = TimeoutUnawareTransport.new(@server) - session = ServerSession.new(server: @server, transport: transport, session_id: "session-1") - - session.ping(related_request_id: "req-1", timeout: 11) - - assert_equal [{ method: "ping", timeout: :not_passed }], transport.requests - end - end -end diff --git a/test/mcp/server_test.rb b/test/mcp/server_test.rb index 80162e5..0f54cae 100644 --- a/test/mcp/server_test.rb +++ b/test/mcp/server_test.rb @@ -5,8 +5,6 @@ require "test_helper" module MCP class ServerTest < ActiveSupport::TestCase include InstrumentationTestHelper - include InitializeParamsTestHelper - include DeprecationWarningTestHelper setup do @tool = Tool.define( name: "test_tool", @@ -125,596 +123,11 @@ module MCP assert_instrumentation_data({ method: "ping" }) end - test "#handle server/discover returns supported versions, capabilities, server info, and instructions" do - response = @server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }) - result = response[:result] - - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, result[:supportedVersions] - # Without a `subscriptions/listen`-serving transport, the `listChanged` flags are - # stripped from the advertised capabilities (see the dedicated tests below). - assert_equal @server.capabilities.keys, result[:capabilities].keys - # Per the finalized spec (PR #3002), the server identity is the optional `_meta` stamp, - # not a top-level `serverInfo` field. - assert_equal @server_name, result.dig(:_meta, RequestEnvelope::SERVER_INFO_META_KEY, :name) - assert_equal "1.2.3", result.dig(:_meta, RequestEnvelope::SERVER_INFO_META_KEY, :version) - refute result.key?(:serverInfo) - assert_equal "Optional instructions for the client", result[:instructions] - end - - test "#handle server/discover strips listChanged and subscribe flags without a listen-serving transport" do - server = Server.new(name: "discover_test", capabilities: { - tools: { listChanged: true }, - resources: { listChanged: true, subscribe: true }, - logging: {}, - }) - - result = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })[:result] - - assert_equal({ tools: {}, resources: {}, logging: {} }, result[:capabilities]) - end - - test "#handle server/discover keeps listChanged flags when the transport serves subscriptions/listen" do - server = Server.new(name: "discover_test", capabilities: { tools: { listChanged: true } }) - transport = mock - transport.stubs(:serves_subscriptions_listen?).returns(true) - server.transport = transport - - result = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })[:result] - - assert_equal({ tools: { listChanged: true } }, result[:capabilities]) - end - - test "#handle server/discover responds before initialize and regardless of capabilities" do - # Per SEP-2575, discovery is sessionless: no prior `initialize`, no capability gate. - server = Server.new(name: "discover_test", capabilities: {}) - - response = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }) - - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, response.dig(:result, :supportedVersions) - end - - test "#handle server/discover does not mark the session initialized" do - session = ServerSession.new(server: @server, transport: mock) - - @server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }, session: session) - - refute_predicate session, :initialized? - # `initialize` must still succeed afterwards. - response = @server.handle( - { jsonrpc: "2.0", method: "initialize", id: 2, params: initialize_params }, - session: session, - ) - refute_nil response[:result] - end - - test "#handle server/discover omits instructions when the server has none" do - server = Server.new(name: "discover_test") - - response = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }) - - refute response[:result].key?(:instructions) - end - - test "#handle server/discover always carries the required cache hints with spec defaults" do - # Unlike the opt-in SEP-2549 hints on list/read results, `ttlMs`/`cacheScope` - # are REQUIRED on `DiscoverResult`. - server = Server.new(name: "discover_test") - - result = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })[:result] - - assert_equal 0, result[:ttlMs] - assert_equal "private", result[:cacheScope] - end - - test "#handle server/discover reuses the configured SEP-2549 cache hints" do - server = Server.new(name: "discover_test", ttl_ms: 3_600_000, cache_scope: "public") - - result = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })[:result] - - assert_equal 3_600_000, result[:ttlMs] - assert_equal "public", result[:cacheScope] - end - - test "#define_custom_method raises for server/discover" do - assert_raises(Server::MethodAlreadyDefinedError) do - @server.define_custom_method(method_name: "server/discover") { {} } - end - end - - test "UnsupportedProtocolVersionError surfaces as -32022 with the SEP-2575 data shape" do - server = Server.new(name: "error_test", tools: [TestTool]) - server.define_tool(name: "unsupported_version_tool") do - raise Server::UnsupportedProtocolVersionError, "1900-01-01" - end - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "unsupported_version_tool" }, - }) - - assert_equal ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, response.dig(:error, :code) - assert_equal "Unsupported protocol version", response.dig(:error, :message) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, response.dig(:error, :data, :supported) - assert_equal "1900-01-01", response.dig(:error, :data, :requested) - end - - test "UnsupportedProtocolVersionError reports an unknown requested version" do - error = Server::UnsupportedProtocolVersionError.new(nil) - - assert_equal "unknown", error.error_data[:requested] - end - - test "UnsupportedProtocolVersionError accepts a symbol-keyed request Hash on every Ruby version" do - # On Ruby 2.7, a keyword parameter in `initialize` would make the trailing symbol-keyed Hash split - # into keywords and raise an ArgumentError. - request = { name: "echo", arguments: {}, _meta: {} } - - error = Server::UnsupportedProtocolVersionError.new("1900-01-01", request) - - assert_equal "1900-01-01", error.error_data[:requested] - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, error.error_data[:supported] - end - - test "MissingRequiredClientCapabilityError surfaces as -32021 with the SEP-2575 data shape" do - server = Server.new(name: "error_test", tools: [TestTool]) - server.define_tool(name: "missing_capability_tool") do - raise Server::MissingRequiredClientCapabilityError, { elicitation: {} } - end - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "missing_capability_tool" }, - }) - - assert_equal ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY, response.dig(:error, :code) - assert_equal "Missing required client capability", response.dig(:error, :message) - assert_equal({ elicitation: {} }, response.dig(:error, :data, :requiredCapabilities)) - end - - test "#handle tools/call with a modern envelope exposes per-request client data without touching the session" do - server = Server.new(name: "modern_test", tools: []) - received = nil - server.define_tool(name: "modern_tool") do |server_context:| - received = { - modern: server_context.modern?, - client_info: server_context.client_info, - client_capabilities: server_context.client_capabilities, - protocol_version: server_context.protocol_version, - } - Tool::Response.new([{ type: "text", text: "ok" }]) - end - session = ServerSession.new(server: server, transport: mock) - - response = server.handle( - modern_request("tools/call", { name: "modern_tool", arguments: {} }, capabilities: { elicitation: {} }), - session: session, - ) - - refute_nil response[:result] - assert received[:modern] - assert_equal({ name: "modern_client", version: "2.0" }, received[:client_info]) - assert_equal({ elicitation: {} }, received[:client_capabilities]) - assert_equal "2026-07-28", received[:protocol_version] - # Per SEP-2575, servers MUST NOT infer client state from prior requests, so nothing is stored. - assert_nil session.client - refute_predicate session, :initialized? - end - - test "#handle tools/call with an unsupported envelope version returns -32022" do - server = Server.new(name: "modern_test", tools: []) - called = false - server.define_tool(name: "modern_tool") do - called = true - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - response = server.handle(modern_request("tools/call", { name: "modern_tool" }, version: "2027-01-01")) - - refute called - assert_equal ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, response.dig(:error, :code) - assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, response.dig(:error, :data, :supported) - assert_equal "2027-01-01", response.dig(:error, :data, :requested) - end - - test "#handle rejects a claimed but incomplete envelope with -32602 naming the missing key" do - # A request carrying the `protocolVersion` claim key must be validated, never silently served as legacy: - # the spec maps missing required envelope fields to Invalid params, and the TypeScript and Python classifiers - # answer the same way. - server = Server.new(name: "modern_test", tools: []) - server.define_tool(name: "modern_tool") { Tool::Response.new([{ type: "text", text: "ok" }]) } - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "modern_tool", - arguments: {}, - _meta: { "io.modelcontextprotocol/protocolVersion": "2026-07-28" }, - }, - }) - - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, response.dig(:error, :code) - assert_includes response.dig(:error, :message), "io.modelcontextprotocol/clientCapabilities" - end - - test "#handle serves an envelope without the optional clientInfo" do - # `clientInfo` became optional after the SEP was finalized (spec PR #3002). - server = Server.new(name: "modern_test", tools: []) - received_context = nil - server.define_tool(name: "modern_tool") do |server_context:| - received_context = server_context - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "modern_tool", - arguments: {}, - _meta: { - "io.modelcontextprotocol/protocolVersion": "2026-07-28", - "io.modelcontextprotocol/clientCapabilities": { elicitation: {} }, - }, - }, - }) - - refute_nil response[:result] - assert_predicate received_context, :modern? - assert_nil received_context.client_info - assert_equal({ elicitation: {} }, received_context.client_capabilities) - end - - test "#handle requires the envelope for requests on a modern-locked session" do - server = Server.new(name: "modern_test", tools: []) - server.define_tool(name: "modern_tool") { Tool::Response.new([{ type: "text", text: "ok" }]) } - session = ServerSession.new(server: server, transport: mock, era: :modern) - - response = server.handle( - { jsonrpc: "2.0", method: "tools/call", id: 1, params: { name: "modern_tool" } }, - session: session, - ) - - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, response.dig(:error, :code) - assert_includes response.dig(:error, :message), "io.modelcontextprotocol/protocolVersion" - end - - test "#handle rejects removed lifecycle methods on a modern-locked session with -32601" do - session = ServerSession.new(server: @server, transport: mock, era: :modern) - - Methods::MODERN_REMOVED_METHODS.each_with_index do |method, index| - response = @server.handle( - { jsonrpc: "2.0", method: method, id: index + 1 }, - session: session, - ) - - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code), "expected -32601 for #{method}" - assert_equal index + 1, response[:id], "expected the request id to be preserved for #{method}" - end - end - - test "#handle rejects removed lifecycle methods carrying the envelope before the era locks" do - # `StdioTransport` locks the era only after a response succeeds, so the first request of a connection - # arrives with `era == nil`. The envelope on the request is what identifies it as modern there. - Methods::MODERN_REMOVED_METHODS.each do |method| - session = ServerSession.new(server: @server, transport: mock) - - response = @server.handle(modern_request(method, {}), session: session) - - assert_equal JsonRpcHandler::ErrorCode::METHOD_NOT_FOUND, response.dig(:error, :code), "expected -32601 for #{method}" - end - end - - test "#handle does not let an enveloped initialize lock the era before it is settled" do - # Serving it would negotiate the legacy lifecycle for a request that declared the modern one, - # pinning the connection to the wrong era for its whole lifetime. - session = ServerSession.new(server: @server, transport: mock) - - @server.handle(modern_request("initialize", initialize_params), session: session) - - assert_nil session.era - refute_predicate session, :initialized? - end - - test "#handle serves an enveloped method the modern lifecycle keeps before the era locks" do - session = ServerSession.new(server: @server, transport: mock) - - response = @server.handle(modern_request("tools/list", {}), session: session) - - refute_nil response[:result] - end - - test "#handle counter-offers the latest handshake version for a modern initialize request and locks the legacy era" do - # Per the SEP-2575 era model, the handshake never lands on a modern version: the client is - # counter-offered 2025-11-25 and the connection proceeds on the legacy lifecycle it selected. - session = ServerSession.new(server: @server, transport: mock) - - response = @server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2026-07-28"), - }, - session: session, - ) - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, response.dig(:result, :protocolVersion) - assert_equal :legacy, session.era - end - - test "#handle server/discover requires the envelope on a modern-locked session" do - # The 2026-07-28 conformance requirements reject an envelope-less `server/discover` - # on the modern era with -32602 (SEP-2575). - session = ServerSession.new(server: @server, transport: mock, era: :modern) - - response = @server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }, session: session) - - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, response.dig(:error, :code) - end - - test "#handle server/discover succeeds without an envelope outside the modern era" do - response = @server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 }) - - refute_nil response[:result] - end - - test "#handle tools/call enforces require_client_capability! from the envelope" do - server = Server.new(name: "modern_test", tools: []) - server.define_tool(name: "guarded_tool") do |server_context:| - server_context.require_client_capability!(:elicitation, :form) - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - declared = server.handle( - modern_request("tools/call", { name: "guarded_tool" }, capabilities: { elicitation: { form: {} } }), - ) - undeclared = server.handle(modern_request("tools/call", { name: "guarded_tool" })) - - refute_nil declared[:result] - assert_equal ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY, undeclared.dig(:error, :code) - assert_equal( - { elicitation: { form: {} } }, - undeclared.dig(:error, :data, :requiredCapabilities), - ) - end - - test "#handle tools/call serializes an input_required result on a modern request" do - server = Server.new(name: "mrtr_test", tools: []) - server.define_tool(name: "mrtr_tool") do |server_context:| - if server_context.input_responses - Tool::Response.new([{ type: "text", text: "done" }]) - else - Server::InputRequiredResult.new( - input_requests: { region: { method: "elicitation/create", params: { message: "Which region?" } } }, - request_state: "state-1", - ) - end - end - - response = server.handle( - modern_request("tools/call", { name: "mrtr_tool" }, capabilities: { elicitation: { form: {} } }), - ) - result = response[:result] - - assert_equal "input_required", result[:resultType] - assert_equal "state-1", result[:requestState] - assert_equal( - { method: "elicitation/create", params: { message: "Which region?" } }, - result.dig(:inputRequests, "region"), - ) - end - - test "#handle tools/call retry leg exposes input responses and request state to the handler" do - server = Server.new(name: "mrtr_test", tools: []) - seen = nil - server.define_tool(name: "mrtr_tool") do |server_context:| - seen = { - input_responses: server_context.input_responses, - request_state: server_context.request_state, - region: server_context.input_response(:region), - } - Tool::Response.new([{ type: "text", text: "done" }]) - end - - request = modern_request("tools/call", { - name: "mrtr_tool", - arguments: {}, - inputResponses: { region: { action: "accept", content: { value: "us-east-1" } } }, - requestState: "state-1", - }) - response = server.handle(request) - - refute_nil response[:result] - assert_equal "state-1", seen[:request_state] - assert_equal({ action: "accept", content: { value: "us-east-1" } }, seen[:region]) - assert_equal seen[:region], seen[:input_responses][:region] - end - - test "#handle rejects an input_required result on a legacy request with an internal error" do - # The result type exists only in the 2026-07-28 lifecycle: pre-2026 clients treat - # an unknown resultType as a final result, so it must never reach them. - server = Server.new(name: "mrtr_test", tools: []) - server.define_tool(name: "mrtr_tool") do - Server::InputRequiredResult.new(request_state: "state-1") - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "mrtr_tool" }, - }) - - assert_equal JsonRpcHandler::ErrorCode::INTERNAL_ERROR, response.dig(:error, :code) - end - - test "#handle rejects an input_required result whose embedded requests exceed declared capabilities" do - server = Server.new(name: "mrtr_test", tools: []) - server.define_tool(name: "mrtr_tool") do - Server::InputRequiredResult.new(input_requests: { - region: { method: "elicitation/create", params: { message: "?" } }, - roots: { method: "roots/list" }, - }) - end - - response = server.handle(modern_request("tools/call", { name: "mrtr_tool" }, capabilities: {})) - - assert_equal ErrorCodes::MISSING_REQUIRED_CLIENT_CAPABILITY, response.dig(:error, :code) - assert_equal( - { elicitation: { form: {} }, roots: {} }, - response.dig(:error, :data, :requiredCapabilities), - ) - end - - test "#handle tools/call input_required bypasses output schema validation" do - configuration = Configuration.new(validate_tool_call_results: true) - server = Server.new(name: "mrtr_test", tools: [], configuration: configuration) - server.define_tool(name: "mrtr_tool", output_schema: { properties: { value: { type: "string" } }, required: ["value"] }) do - Server::InputRequiredResult.new(request_state: "state-1") - end - - response = server.handle(modern_request("tools/call", { name: "mrtr_tool" })) - - assert_equal "input_required", response.dig(:result, :resultType) - end - - test "#handle seals and unseals requestState transparently when request_state_security is set" do - security = Server::RequestStateSecurity.new(key: "k" * 32) - server = Server.new(name: "mrtr_test", tools: [], request_state_security: security) - seen_state = nil - server.define_tool(name: "mrtr_tool") do |server_context:| - if server_context.request_state - seen_state = server_context.request_state - Tool::Response.new([{ type: "text", text: "done" }]) - else - Server::InputRequiredResult.new(request_state: "plain-state") - end - end - - first = server.handle(modern_request("tools/call", { name: "mrtr_tool", arguments: {} })) - sealed = first.dig(:result, :requestState) - - assert sealed.start_with?("v1.") - refute_equal "plain-state", sealed - - retry_response = server.handle(modern_request("tools/call", { - name: "mrtr_tool", - arguments: {}, - requestState: sealed, - })) - - refute_nil retry_response[:result] - # The handler reads the plaintext it originally wrote. - assert_equal "plain-state", seen_state - end - - test "#handle rejects a tampered or cross-call requestState echo with -32602" do - security = Server::RequestStateSecurity.new(key: "k" * 32) - server = Server.new(name: "mrtr_test", tools: [], request_state_security: security) - server.define_tool(name: "mrtr_tool") do |server_context:| - if server_context.request_state - Tool::Response.new([{ type: "text", text: "done" }]) - else - Server::InputRequiredResult.new(request_state: "plain-state") - end - end - - first = server.handle(modern_request("tools/call", { name: "mrtr_tool", arguments: {} })) - sealed = first.dig(:result, :requestState) - - tampered = server.handle(modern_request("tools/call", { - name: "mrtr_tool", - arguments: {}, - requestState: sealed.sub("v1.", "v1.x"), - })) - # Different arguments than the sealing call: the digest claim no longer matches. - cross_call = server.handle(modern_request("tools/call", { - name: "mrtr_tool", - arguments: { other: true }, - requestState: sealed, - })) - - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, tampered.dig(:error, :code) - assert_equal "Invalid or expired requestState", tampered.dig(:error, :message) - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, cross_call.dig(:error, :code) - end - - test "#handle passes requestState through untouched without request_state_security" do - server = Server.new(name: "mrtr_test", tools: []) - seen_state = nil - server.define_tool(name: "mrtr_tool") do |server_context:| - seen_state = server_context.request_state - Tool::Response.new([{ type: "text", text: "done" }]) - end - - server.handle(modern_request("tools/call", { name: "mrtr_tool", requestState: "raw-state" })) - - assert_equal "raw-state", seen_state - end - - test "#handle prompts/get serializes an input_required result on a modern request" do - server = Server.new(name: "mrtr_test") - server.define_prompt(name: "mrtr_prompt", arguments: []) do |_args, server_context:| - server_context.request_state # participates via server_context: - Server::InputRequiredResult.new(request_state: "prompt-state") - end - - response = server.handle(modern_request("prompts/get", { name: "mrtr_prompt", arguments: {} })) - - assert_equal "input_required", response.dig(:result, :resultType) - assert_equal "prompt-state", response.dig(:result, :requestState) - end - - test "#handle resources/read passes an input_required result through unwrapped and without cache hints" do - server = Server.new(name: "mrtr_test", ttl_ms: 5000, cache_scope: "public") - server.resources_read_handler do |_params, server_context:| - server_context.request_state - Server::InputRequiredResult.new(request_state: "resource-state") - end - - response = server.handle(modern_request("resources/read", { uri: "file:///pending.txt" })) - result = response[:result] - - assert_equal "input_required", result[:resultType] - assert_equal "resource-state", result[:requestState] - refute result.key?(:contents) - refute result.key?(:ttlMs) - refute result.key?(:cacheScope) - end - - test "ServerSession locks the legacy era on mark_initialized! and refuses to flip eras" do - session = ServerSession.new(server: @server, transport: mock) - - assert_nil session.era - session.mark_initialized! - assert_equal :legacy, session.era - - session.lock_era!(:legacy) - assert_equal :legacy, session.era - assert_raises(RuntimeError) { session.lock_era!(:modern) } - end - - test "ServerSession accepts a preset era and validates era values" do - session = ServerSession.new(server: @server, transport: mock, era: :modern) - - assert_equal :modern, session.era - assert_raises(ArgumentError) { ServerSession.new(server: @server, transport: mock, era: :future) } - assert_raises(ArgumentError) { session.lock_era!(:future) } - end - test "#handle initialize request returns protocol info, server info, and capabilities" do request = { jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = @server.handle(request) @@ -724,12 +137,11 @@ module MCP jsonrpc: "2.0", id: 1, result: { - protocolVersion: Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, + protocolVersion: Configuration::LATEST_STABLE_PROTOCOL_VERSION, capabilities: { prompts: { listChanged: true }, resources: { listChanged: true }, tools: { listChanged: true }, - logging: {}, }, serverInfo: { description: "Test server", @@ -743,205 +155,7 @@ module MCP } assert_equal expected_result, response - assert_instrumentation_data({ method: "initialize", client: { name: "test-client", version: "1.0.0" } }) - end - - test "#handle initialize result carries declared capability extensions" do - server = Server.new( - name: "extensions_test", - capabilities: { - tools: { listChanged: true }, - extensions: { "com.example/feature" => { enabled: true } }, - }, - ) - - response = server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - - assert_equal( - { "com.example/feature" => { enabled: true } }, - response.dig(:result, :capabilities, :extensions), - ) - end - - test "Server.new accepts an MCP::Server::Capabilities instance" do - capabilities = Server::Capabilities.new - capabilities.support_tools - capabilities.support_extensions("io.modelcontextprotocol/tasks" => {}) - - server = Server.new(name: "extensions_test", capabilities: capabilities) - response = server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - - assert_equal( - { - tools: {}, - extensions: { "io.modelcontextprotocol/tasks" => {} }, - }, - response.dig(:result, :capabilities), - ) - end - - test "client-declared capability extensions are readable via client_capabilities" do - extensions = { "com.example/feature": { enabled: true } } - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(capabilities: { extensions: extensions }), - } - - @server.handle(request) - - assert_equal extensions, @server.client_capabilities[:extensions] - end - - test "client-declared capability extensions are readable via the session" do - session = ServerSession.new(server: @server, transport: mock) - extensions = { "com.example/feature": {} } - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(capabilities: { extensions: extensions }), - } - - @server.handle(request, session: session) - - assert_equal extensions, session.client_capabilities[:extensions] - end - - test "#handle initialize request with clientInfo includes client in instrumentation data" do - client_info = { name: "test_client", version: "1.0.0" } - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(clientInfo: client_info), - } - - @server.handle(request) - assert_instrumentation_data({ method: "initialize", client: client_info }) - end - - test "instrumentation data includes client info for subsequent requests after initialize" do - client_info = { name: "test_client", version: "1.0.0" } - initialize_request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(clientInfo: client_info), - } - @server.handle(initialize_request) - - ping_request = { - jsonrpc: "2.0", - method: "ping", - id: 2, - } - @server.handle(ping_request) - assert_instrumentation_data({ method: "ping", client: client_info }) - end - - test "#handle rejects duplicate initialize on an already-initialized session with -32600" do - session = ServerSession.new(server: @server, transport: mock) - - first_request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(clientInfo: { name: "original", version: "1.0" }), - } - first_response = @server.handle(first_request, session: session) - refute_nil first_response[:result] - - second_request = { - jsonrpc: "2.0", - method: "initialize", - id: 2, - params: initialize_params(clientInfo: { name: "intruder", version: "9.9" }, protocolVersion: "2024-11-05"), - } - second_response = @server.handle(second_request, session: session) - - assert_equal JsonRpcHandler::ErrorCode::INVALID_REQUEST, second_response[:error][:code] - assert_equal "Invalid Request", second_response[:error][:message] - assert_equal({ name: "original", version: "1.0" }, session.client) - end - - test "#handle initialize with empty params returns -32602 and does not initialize the session" do - session = ServerSession.new(server: @server, transport: mock) - - response = @server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: {} }, session: session) - - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - refute_predicate session, :initialized? - end - - test "#handle initialize without params returns -32602" do - response = @server.handle({ jsonrpc: "2.0", method: "initialize", id: 1 }) - - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - end - - test "#handle initialize with a missing required field returns -32602" do - [:protocolVersion, :capabilities, :clientInfo].each do |field| - params = initialize_params.tap { |hash| hash.delete(field) } - - response = @server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: params }) - - assert_equal(-32602, response[:error][:code], "expected -32602 when #{field} is missing") - assert_includes response[:error][:data], field.to_s - end - end - - test "#handle initialize with clientInfo missing name or version returns -32602" do - [{ name: "client-without-version" }, { version: "1.0.0" }].each do |client_info| - response = @server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(clientInfo: client_info), - }) - - assert_equal(-32602, response[:error][:code]) - assert_includes response[:error][:data], "clientInfo" - end - end - - test "#handle initialize with an unsupported protocolVersion still negotiates the fallback version" do - response = @server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "1999-01-01"), - }) - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, response[:result][:protocolVersion] - end - - test "instrumentation data does not include client key when no clientInfo provided" do - request = { - jsonrpc: "2.0", - method: "ping", - id: 1, - } - - @server.handle(request) - assert_instrumentation_data({ method: "ping" }) - end - - test "unsupported method instrumentation includes client from session" do - session = ServerSession.new(server: @server, transport: mock) - session.store_client_info(client: { name: "session-client", version: "1.0" }) - - request = { - jsonrpc: "2.0", - method: "does/not/exist", - id: 1, - } - - @server.handle(request, session: session) - assert_instrumentation_data({ method: "unsupported_method", client: { name: "session-client", version: "1.0" } }) + assert_instrumentation_data({ method: "initialize" }) end test "#handle returns nil for notification requests" do @@ -987,9 +201,7 @@ module MCP assert_equal "test_tool", result[:tools][0][:name] assert_equal "Test tool", result[:tools][0][:title] assert_equal "A test tool", result[:tools][0][:description] - assert_equal( - { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" }, result[:tools][0][:inputSchema] - ) + assert_equal({ type: "object" }, result[:tools][0][:inputSchema]) assert_equal({ foo: "bar" }, result[:tools][0][:_meta]) assert_instrumentation_data({ method: "tools/list" }) end @@ -1010,22 +222,21 @@ module MCP assert_equal({ foo: "bar" }, result[:tools][0][:_meta]) end - test "#handle tools/list emits 2020-12 $schema on inputSchema and outputSchema" do - tool_with_output = Tool.define( - name: "tool_with_output", - description: "tool with output schema", - input_schema: { properties: { msg: { type: "string" } } }, - output_schema: { properties: { result: { type: "string" } } }, - ) do - Tool::Response.new([{ type: "text", content: "OK" }]) + test "#tools_list_handler sets the tools/list handler" do + @server.tools_list_handler do + [{ name: "hammer", description: "Hammer time!" }] end - server = Server.new(name: "test_server", tools: [tool_with_output]) - response = server.handle({ jsonrpc: "2.0", method: "tools/list", id: 1 }) - tool = response[:result][:tools][0] + request = { + jsonrpc: "2.0", + method: "tools/list", + id: 1, + } - assert_equal "https://json-schema.org/draft/2020-12/schema", tool[:inputSchema][:"$schema"] - assert_equal "https://json-schema.org/draft/2020-12/schema", tool[:outputSchema][:"$schema"] + response = @server.handle(request) + result = response[:result] + assert_equal({ tools: [{ name: "hammer", description: "Hammer time!" }] }, result) + assert_instrumentation_data({ method: "tools/list" }) end test "#handle tools/call executes tool and returns result" do @@ -1035,7 +246,7 @@ module MCP if RUBY_VERSION >= "3.1" # Ruby 3.1+: Mocha stub preserves `method.parameters` info. - @tool.expects(:call).with(arg: "value", server_context: is_a(ServerContext)).returns(tool_response) + @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response) else # Ruby 3.0: Mocha stub changes `method.parameters`, so `accepts_server_context?` returns false. @tool.expects(:call).with(arg: "value").returns(tool_response) @@ -1053,58 +264,10 @@ module MCP response = @server.handle(request) assert_equal tool_response.to_h, response[:result] - assert_instrumentation_data({ method: "tools/call", tool_name: tool_name, tool_arguments: tool_args }) + assert_instrumentation_data({ method: "tools/call", tool_name: tool_name }) end - test "#handle_json tools/call delivers nested object arguments with symbol keys at every level" do - received_payload = nil - server = Server.new(name: "test_server") - server.define_tool( - name: "nested_args_tool", - input_schema: { properties: { message: { type: "string" }, payload: { type: "object" } }, required: ["message"] }, - ) do |message:, payload: nil, server_context:| - received_payload = payload - Tool::Response.new([{ type: "text", text: "#{message} #{server_context.class}" }]) - end - - request_json = JSON.generate( - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "nested_args_tool", - arguments: { message: "hi", payload: { subject: "greet", nested: { deep: "value" } } }, - }, - ) - - server.handle_json(request_json) - - assert_equal({ subject: "greet", nested: { deep: "value" } }, received_payload) - assert_equal "greet", received_payload[:subject] - assert_nil received_payload["subject"] - end - - test "tool receives symbol keys when called under the JSON-round-tripped argument shape" do - received_payload = nil - tool = Tool.define( - name: "nested_args_tool", - input_schema: { properties: { payload: { type: "object" } } }, - ) do |payload: nil, server_context:| - received_payload = payload - Tool::Response.new([{ type: "text", text: server_context.class.to_s }]) - end - - # Round-trip the arguments through JSON the way a transport does, so the tool - # is exercised under the symbolized shape it actually receives at runtime. - arguments = { payload: { "subject" => "greet" } } - delivered = JSON.parse(JSON.generate(arguments), symbolize_names: true) - tool.call(**delivered, server_context: nil) - - assert_equal({ subject: "greet" }, received_payload) - assert_nil received_payload["subject"] - end - - test "#handle tools/call returns tool execution error if required tool arguments are missing" do + test "#handle tools/call returns error response with isError true if required tool arguments are missing" do tool_with_required_argument = Tool.define( name: "test_tool", title: "Test tool", @@ -1128,10 +291,10 @@ module MCP response = server.handle(request) - assert_nil response[:error] - assert(response[:result][:isError]) + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] assert_equal "text", response[:result][:content][0][:type] - assert_includes response[:result][:content][0][:text], "Missing required arguments: message" + assert_equal "Missing required arguments: message", response[:result][:content][0][:text] end test "#handle_json tools/call executes tool and returns result" do @@ -1141,7 +304,7 @@ module MCP if RUBY_VERSION >= "3.1" # Ruby 3.1+: Mocha stub preserves `method.parameters` info. - @tool.expects(:call).with(arg: "value", server_context: is_a(ServerContext)).returns(tool_response) + @tool.expects(:call).with(arg: "value", server_context: nil).returns(tool_response) else # Ruby 3.0: Mocha stub changes `method.parameters`, so `accepts_server_context?` returns false. @tool.expects(:call).with(arg: "value").returns(tool_response) @@ -1157,7 +320,7 @@ module MCP raw_response = @server.handle_json(request) response = JSON.parse(raw_response, symbolize_names: true) if raw_response assert_equal tool_response.to_h, response[:result] if response - assert_instrumentation_data({ method: "tools/call", tool_name: tool_name, tool_arguments: { arg: "value" } }) + assert_instrumentation_data({ method: "tools/call", tool_name: tool_name }) end test "#handle_json tools/call executes tool and returns result, when the tool is typed with Sorbet" do @@ -1199,7 +362,17 @@ module MCP assert_equal({ content: [{ type: "text", content: "OK" }], isError: false }, response[:result]) end - test "#handle tools/call returns protocol error in JSON-RPC format if the tool raises an uncaught exception" do + test "#handle tools/call returns error response with isError true if the tool raises an error" do + @server.configuration.exception_reporter.expects(:call).with do |exception, server_context| + assert_not_nil exception + assert_equal( + { + request: { name: "tool_that_raises", arguments: { message: "test" } }, + }, + server_context, + ) + end + request = { jsonrpc: "2.0", method: "tools/call", @@ -1210,18 +383,13 @@ module MCP id: 1, } - @server.configuration.exception_reporter.expects(:call).with do |exception, server_context| - refute_kind_of MCP::Server::RequestHandlerError, exception - assert_equal({ request: request }, server_context) - end - response = @server.handle(request) - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool tool_that_raises", response[:error][:data] - assert_instrumentation_data({ method: "tools/call", tool_name: "tool_that_raises", tool_arguments: { message: "test" }, error: :internal_error }) + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_match(/Internal error calling tool tool_that_raises: /, response[:result][:content][0][:text]) + assert_instrumentation_data({ method: "tools/call", tool_name: "tool_that_raises" }) end test "registers tools with the same class name in different namespaces" do @@ -1262,7 +430,7 @@ module MCP MESSAGE end - test "#handle_json returns protocol error in JSON-RPC format if the tool raises an uncaught exception" do + test "#handle_json returns error response with isError true if the tool raises an error" do request = JSON.generate({ jsonrpc: "2.0", method: "tools/call", @@ -1274,14 +442,14 @@ module MCP }) response = JSON.parse(@server.handle_json(request), symbolize_names: true) - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool tool_that_raises", response[:error][:data] - assert_instrumentation_data({ method: "tools/call", tool_name: "tool_that_raises", tool_arguments: { message: "test" }, error: :internal_error }) + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_match(/Internal error calling tool tool_that_raises: /, response[:result][:content][0][:text]) + assert_instrumentation_data({ method: "tools/call", tool_name: "tool_that_raises" }) end - test "#handle tools/call returns protocol error in JSON-RPC format if input_schema raises an error during validation" do + test "#handle tools/call returns error response with isError true if input_schema raises an error during validation" do tool = Tool.define( name: "tool_with_faulty_schema", title: "Tool with faulty schema", @@ -1305,13 +473,13 @@ module MCP response = server.handle(request) - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool tool_with_faulty_schema", response[:error][:data] + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_match(/Internal error calling tool tool_with_faulty_schema: Unexpected schema error/, response[:result][:content][0][:text]) end - test "#handle tools/call returns JSON-RPC error for unknown tool" do + test "#handle tools/call returns error response with isError true for unknown tool" do request = { jsonrpc: "2.0", method: "tools/call", @@ -1323,14 +491,14 @@ module MCP } response = @server.handle(request) - assert_nil response[:result] - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - assert_includes response[:error][:data], "Tool not found: unknown_tool" - assert_instrumentation_data({ method: "tools/call", tool_name: "unknown_tool", error: :invalid_params }) + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_equal "Tool not found: unknown_tool", response[:result][:content][0][:text] + assert_instrumentation_data({ method: "tools/call", tool_name: "unknown_tool", error: :tool_not_found }) end - test "#handle_json returns JSON-RPC error for unknown tool" do + test "#handle_json returns error response with isError true for unknown tool" do request = JSON.generate({ jsonrpc: "2.0", method: "tools/call", @@ -1342,10 +510,28 @@ module MCP }) response = JSON.parse(@server.handle_json(request), symbolize_names: true) - assert_nil response[:result] - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - assert_includes response[:error][:data], "Tool not found: unknown_tool" + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] + assert_equal "text", response[:result][:content][0][:type] + assert_equal "Tool not found: unknown_tool", response[:result][:content][0][:text] + end + + test "#tools_call_handler sets the tools/call handler" do + @server.tools_call_handler do |request| + tool_name = request[:name] + Tool::Response.new("#{tool_name} called successfully").to_h + end + + request = { + jsonrpc: "2.0", + method: "tools/call", + params: { name: "my_tool", arguments: {} }, + id: 1, + } + + response = @server.handle(request) + assert_equal({ content: "my_tool called successfully", isError: false }, response[:result]) + assert_instrumentation_data({ method: "tools/call" }) end test "#handle prompts/list returns list of prompts" do @@ -1360,6 +546,22 @@ module MCP assert_instrumentation_data({ method: "prompts/list" }) end + test "#prompts_list_handler sets the prompts/list handler" do + @server.prompts_list_handler do + [{ name: "foo_prompt", description: "Foo prompt" }] + end + + request = { + jsonrpc: "2.0", + method: "prompts/list", + id: 1, + } + + response = @server.handle(request) + assert_equal({ prompts: [{ name: "foo_prompt", description: "Foo prompt" }] }, response[:result]) + assert_instrumentation_data({ method: "prompts/list" }) + end + test "#handle prompts/get returns templated prompt" do request = { jsonrpc: "2.0", @@ -1395,9 +597,6 @@ module MCP } response = @server.handle(request) - # An unknown prompt is client input, so it maps to Invalid Params (-32602), not the - # default Internal Error (-32603); matches the tools/call and completion/complete siblings. - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, response.dig(:error, :code) assert_equal("Prompt not found unknown_prompt", response[:error][:data]) assert_instrumentation_data({ method: "prompts/get", error: :prompt_not_found }) end @@ -1414,9 +613,6 @@ module MCP } response = @server.handle(request) - # A missing required argument is client input, so it maps to Invalid Params (-32602), - # not the default Internal Error (-32603). - assert_equal JsonRpcHandler::ErrorCode::INVALID_PARAMS, response.dig(:error, :code) assert_equal "Missing required arguments: test_argument", response[:error][:data] assert_instrumentation_data({ method: "prompts/get", @@ -1425,6 +621,32 @@ module MCP }) end + test "#prompts_get_handler sets the prompts/get handler" do + @server.prompts_get_handler do |request| + prompt_name = request[:name] + Prompt::Result.new( + description: prompt_name, + messages: [ + Prompt::Message.new(role: "user", content: Content::Text.new(request[:arguments]["foo"])), + ], + ).to_h + end + + request = { + jsonrpc: "2.0", + method: "prompts/get", + id: 1, + params: { name: "foo_bar_prompt", arguments: { "foo" => "bar" } }, + } + + response = @server.handle(request) + assert_equal( + { description: "foo_bar_prompt", messages: [{ role: "user", content: { type: "text", text: "bar" } }] }, + response[:result], + ) + assert_instrumentation_data({ method: "prompts/get" }) + end + test "#handle resources/list returns a list of resources" do request = { jsonrpc: "2.0", @@ -1437,52 +659,23 @@ module MCP assert_instrumentation_data({ method: "resources/list" }) end - test "#resources_list_handler replaces the served resource collection" do - other = Resource.new(uri: "https://other.invalid", name: "other", mime_type: "text/plain") - @server.resources_list_handler { |_params| [other] } - - response = @server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - - assert_equal({ resources: [other.to_h] }, response[:result]) - end - - test "#resources_list_handler receives server_context when it opts in" do - real = Resource.new(uri: "https://real.invalid", name: "real", mime_type: "text/plain") - demo = Resource.new(uri: "https://demo.invalid", name: "demo", mime_type: "text/plain") - @server.resources_list_handler do |_params, server_context:| - server_context[:authenticated] ? [real] : [demo] + test "#resources_list_handler sets the resources/list handler" do + @server.resources_list_handler do + [{ uri: "https://test_resource.invalid", name: "test-resource", title: "Test Resource", description: "Test resource" }] end - @server.server_context = { authenticated: false } - anon = @server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - @server.server_context = { authenticated: true } - authed = @server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) + request = { + jsonrpc: "2.0", + method: "resources/list", + id: 1, + } - assert_equal({ resources: [demo.to_h] }, anon[:result]) - assert_equal({ resources: [real.to_h] }, authed[:result]) - end - - test "#resources_list_handler paginates and stamps cache hints on the returned collection" do - first = Resource.new(uri: "https://first.invalid", name: "first", mime_type: "text/plain") - second = Resource.new(uri: "https://second.invalid", name: "second", mime_type: "text/plain") - server = Server.new(name: @server_name, resources: [], page_size: 1, ttl_ms: 60_000) - server.resources_list_handler { |_params| [first, second] } - - response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - - assert_equal([first.to_h], response[:result][:resources]) - assert_equal("1", response[:result][:nextCursor]) - assert_equal(60_000, response[:result][:ttlMs]) - end - - test "#resources_list_handler serves a server with no constructor-provided resources" do - only = Resource.new(uri: "https://only.invalid", name: "only", mime_type: "text/plain") - server = Server.new(name: @server_name, resources: []) - server.resources_list_handler { |_params| [only] } - - response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - - assert_equal({ resources: [only.to_h] }, response[:result]) + response = @server.handle(request) + assert_equal( + { resources: [{ uri: "https://test_resource.invalid", name: "test-resource", title: "Test Resource", description: "Test resource" }] }, + response[:result], + ) + assert_instrumentation_data({ method: "resources/list" }) end test "#handle resources/read returns an empty array of contents by default" do @@ -1525,25 +718,6 @@ module MCP ) end - test "#handle resources/read returns -32602 with the uri in error data when the handler raises ResourceNotFoundError" do - # Per SEP-2164, resource-not-found errors use the standard JSON-RPC Invalid Params code (-32602) - # and carry the requested URI in `data`. - @server.resources_read_handler do |request| - raise Server::ResourceNotFoundError.new(request[:uri], request) - end - - response = @server.handle({ - jsonrpc: "2.0", - method: "resources/read", - id: 1, - params: { uri: "file:///missing.txt" }, - }) - - assert_equal(-32602, response[:error][:code]) - assert_equal("Resource not found: file:///missing.txt", response[:error][:message]) - assert_equal({ uri: "file:///missing.txt" }, response[:error][:data]) - end - test "#handle resources/templates/list returns a list of resource templates" do request = { jsonrpc: "2.0", @@ -1561,327 +735,31 @@ module MCP assert_instrumentation_data({ method: "resources/templates/list" }) end - class GreetingResource < Resource - uri "greeting://hello" - resource_name "greeting" - mime_type "text/plain" - - class << self - def contents - [Resource::TextContents.new(uri: uri, mime_type: mime_type, text: "hello")] - end + test "#resources_templates_list_handler sets the resources/templates/list handler" do + @server.resources_templates_list_handler do + [{ uriTemplate: "test_resource_template/{id}", name: "Test resource template", description: "a template" }] end - end - class UserProfileTemplate < ResourceTemplate - uri_template "users://{user_id}/profile" - resource_template_name "user_profile" - mime_type "text/plain" - - class << self - def contents(user_id:) - [Resource::TextContents.new(uri: "users://#{user_id}/profile", mime_type: mime_type, text: "profile of #{user_id}")] - end - end - end - - def read_resource_request(uri) - { + request = { jsonrpc: "2.0", - method: "resources/read", + method: "resources/templates/list", id: 1, - params: { uri: uri }, } - end - test "#handle resources/read auto-routes to a class-based resource by exact URI" do - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - server = Server.new(name: "test_server", resources: [GreetingResource], configuration: configuration) - - response = server.handle(read_resource_request("greeting://hello")) - - expected = [{ uri: "greeting://hello", mimeType: "text/plain", text: "hello" }] - assert_equal({ contents: expected }, response[:result]) - assert_instrumentation_data({ method: "resources/read", resource_uri: "greeting://hello" }) - end - - test "#handle resources/read wraps a single contents object returned by a class-based resource" do - resource = Resource.define(uri: "single://one", name: "single") do - Resource::TextContents.new(uri: "single://one", mime_type: "text/plain", text: "only one") - end - server = Server.new(name: "test_server", resources: [resource]) - - response = server.handle(read_resource_request("single://one")) - - expected = [{ uri: "single://one", mimeType: "text/plain", text: "only one" }] - assert_equal({ contents: expected }, response[:result]) - end - - test "#handle resources/read passes server_context to contents that opt in" do - received = nil - resource = Resource.define(uri: "ctx://resource", name: "ctx") do |server_context:| - received = server_context - [Resource::TextContents.new(uri: "ctx://resource", mime_type: "text/plain", text: "ctx")] - end - server = Server.new(name: "test_server", resources: [resource]) - - server.handle(read_resource_request("ctx://resource")) - - assert_instance_of ServerContext, received - end - - test "#handle resources/read auto-routes to a class-based resource template with extracted params" do - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - server = Server.new(name: "test_server", resource_templates: [UserProfileTemplate], configuration: configuration) - - response = server.handle(read_resource_request("users://42/profile")) - - expected = [{ uri: "users://42/profile", mimeType: "text/plain", text: "profile of 42" }] - assert_equal({ contents: expected }, response[:result]) - assert_instrumentation_data({ - method: "resources/read", - resource_uri: "users://42/profile", - resource_template: "users://{user_id}/profile", - }) - end - - test "#handle resources/read prefers an exact resource match over a template match" do - resource = Resource.define(uri: "users://42/profile", name: "pinned_profile") do - [Resource::TextContents.new(uri: "users://42/profile", mime_type: "text/plain", text: "pinned")] - end - server = Server.new(name: "test_server", resources: [resource], resource_templates: [UserProfileTemplate]) - - response = server.handle(read_resource_request("users://42/profile")) - - assert_equal "pinned", response[:result][:contents].first[:text] - end - - test "#handle resources/read returns -32602 for an unknown URI when class-based resources are registered" do - server = Server.new(name: "test_server", resources: [GreetingResource]) - - response = server.handle(read_resource_request("greeting://unknown")) - - assert_equal(-32602, response[:error][:code]) - assert_equal("Resource not found: greeting://unknown", response[:error][:message]) - assert_equal({ uri: "greeting://unknown" }, response[:error][:data]) - end - - test "#handle resources/read returns -32602 for a non-matching URI when class-based templates are registered" do - server = Server.new(name: "test_server", resource_templates: [UserProfileTemplate]) - - response = server.handle(read_resource_request("users://42/settings")) - - assert_equal(-32602, response[:error][:code]) - assert_equal({ uri: "users://42/settings" }, response[:error][:data]) - end - - test "#handle resources/read keeps returning [] for unknown URIs when only instance-based resources are registered" do - server = Server.new(name: "test_server", resources: [@resource], resource_templates: [@resource_template]) - - response = server.handle(read_resource_request("unknown://resource")) - - assert_equal({ contents: [] }, response[:result]) - end - - test "#resources_read_handler overrides auto-routing for class-based resources" do - server = Server.new(name: "test_server", resources: [GreetingResource]) - server.resources_read_handler do |request| - [{ uri: request[:uri], mimeType: "text/plain", text: "handler wins" }] - end - - response = server.handle(read_resource_request("greeting://hello")) - - assert_equal "handler wins", response[:result][:contents].first[:text] - end - - test "#handle resources/list and resources/templates/list render class-based and instance-based entries together" do - server = Server.new( - name: "test_server", - resources: [@resource, GreetingResource], - resource_templates: [@resource_template, UserProfileTemplate], - ) - - list_response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - assert_equal [@resource.to_h, GreetingResource.to_h], list_response[:result][:resources] - - templates_response = server.handle({ jsonrpc: "2.0", method: "resources/templates/list", id: 1 }) - assert_equal [@resource_template.to_h, UserProfileTemplate.to_h], templates_response[:result][:resourceTemplates] - end - - test "#resources= rebuilds the resource index used for auto-routing" do - server = Server.new(name: "test_server", resources: [GreetingResource]) - - replacement = Resource.define(uri: "replacement://res", name: "replacement") do - [Resource::TextContents.new(uri: "replacement://res", mime_type: "text/plain", text: "replaced")] - end - server.resources = [replacement] - - response = server.handle(read_resource_request("replacement://res")) - assert_equal "replaced", response[:result][:contents].first[:text] - - stale_response = server.handle(read_resource_request("greeting://hello")) - assert_equal(-32602, stale_response[:error][:code]) - end - - test "#define_resource registers a resource served by auto-routing" do - server = Server.new(name: "test_server") - server.define_resource(uri: "defined://res", name: "defined", mime_type: "text/plain") do - [Resource::TextContents.new(uri: "defined://res", mime_type: "text/plain", text: "defined body")] - end - - list_response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - assert_equal ["defined"], list_response[:result][:resources].map { |resource| resource[:name] } - - response = server.handle(read_resource_request("defined://res")) - assert_equal "defined body", response[:result][:contents].first[:text] - end - - test "#define_resource_template registers a template served by auto-routing" do - server = Server.new(name: "test_server") - server.define_resource_template(uri_template: "items://{item_id}", name: "item_template") do |item_id:| - [Resource::TextContents.new(uri: "items://#{item_id}", mime_type: "text/plain", text: "item #{item_id}")] - end - - templates_response = server.handle({ jsonrpc: "2.0", method: "resources/templates/list", id: 1 }) - assert_equal ["item_template"], templates_response[:result][:resourceTemplates].map { |template| template[:name] } - - response = server.handle(read_resource_request("items://7")) - assert_equal "item 7", response[:result][:contents].first[:text] - end - - test "#configure_logging_level returns empty hash on success" do - response = @server.handle( + response = @server.handle(request) + assert_equal( { - jsonrpc: "2.0", - id: 1, - method: "logging/setLevel", - params: { - level: "info", - }, - }, - ) - - assert_equal "2.0", response[:jsonrpc] - assert_equal 1, response[:id] - assert_equal({}, response[:result]) - refute response.key?(:error) - end - - test "#configure_logging_level does not warn after a modern initialize request is counter-offered" do - # `initialize` asking for 2026-07-28 lands on 2025-11-25, where logging is not deprecated, - # so no warning fires. On the modern lifecycle itself `logging/setLevel` is a removed method - # and never reaches this handler. - server = Server.new(tools: [TestTool]) - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2026-07-28", - capabilities: {}, - clientInfo: { name: "test-client", version: "1.0" }, - }, - }, - ) - - response = nil - assert_no_deprecation_warning do - response = server.handle( - { - jsonrpc: "2.0", - id: 2, - method: "logging/setLevel", - params: { - level: "info", + resourceTemplates: [ + { + uriTemplate: "test_resource_template/{id}", + name: "Test resource template", + description: "a template", }, - }, - ) - end - - assert_empty response[:result] - end - - test "#configure_logging_level does not warn when negotiated protocol version is older" do - server = Server.new(tools: [TestTool]) - server.handle( - { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - capabilities: {}, - clientInfo: { name: "test-client", version: "1.0" }, - }, + ], }, + response[:result], ) - - assert_no_deprecation_warning do - server.handle( - { - jsonrpc: "2.0", - id: 2, - method: "logging/setLevel", - params: { - level: "info", - }, - }, - ) - end - end - - test "#configure_logging_level returns an error object when invalid log level is provided" do - server = Server.new( - tools: [TestTool], - configuration: Configuration.new(validate_tool_call_arguments: true), - ) - - response = server.handle( - { - jsonrpc: "2.0", - id: 1, - method: "logging/setLevel", - params: { - level: "invalid_level", - }, - }, - ) - - assert_equal "2.0", response[:jsonrpc] - assert_equal 1, response[:id] - assert_equal(-32602, response[:error][:code]) - assert_includes response[:error][:data], "Invalid log level invalid_level" - end - - test "#configure_logging_level returns an error object when server has not logging capability" do - server = Server.new( - tools: [TestTool], - configuration: Configuration.new(validate_tool_call_arguments: true), - capabilities: { - tools: { listChanged: true }, - prompts: { listChanged: true }, - resources: { listChanged: true }, - }, - ) - - response = server.handle( - { - jsonrpc: "2.0", - id: 1, - method: "logging/setLevel", - params: { - level: "debug", - }, - }, - ) - - assert_equal "2.0", response[:jsonrpc] - assert_equal 1, response[:id] - assert_equal(-32603, response[:error][:code]) - assert_includes response[:error][:data], "Server does not support logging" + assert_instrumentation_data({ method: "resources/templates/list" }) end test "#handle method with missing required top-level capability returns an error" do @@ -1947,263 +825,6 @@ module MCP assert_instrumentation_data({ method: "notify" }) end - test "#handle tools/call invokes around_request with correct data" do - call_log = [] - data_before = nil - data_after = nil - - configuration = MCP::Configuration.new - configuration.instrumentation_callback = instrumentation_helper.callback - configuration.around_request = ->(data, &request_handler) { - data_before = data.dup - call_log << :before - request_handler.call - call_log << :after - data_after = data.dup - } - - tool = Tool.define(name: "around_test_tool", description: "Test") do |arg:| - Tool::Response.new([{ type: "text", text: arg }]) - end - - server = Server.new(name: "test_server", tools: [tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "around_test_tool", arguments: { arg: "hello" } }, - id: 1, - } - - server.handle(request) - - assert_equal([:before, :after], call_log) - assert_equal("tools/call", data_before[:method]) - assert_nil(data_before[:tool_name]) - assert_equal("around_test_tool", data_after[:tool_name]) - assert_equal({ arg: "hello" }, data_after[:tool_arguments]) - end - - test "#handle around_request and instrumentation_callback coexist" do - around_called = false - callback_data = nil - - configuration = MCP::Configuration.new - configuration.around_request = ->(_data, &request_handler) { - around_called = true - request_handler.call - } - configuration.instrumentation_callback = ->(data) { - callback_data = data.dup - } - - server = Server.new(name: "test_server", configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "ping", - id: 1, - } - - server.handle(request) - - assert(around_called) - assert_equal("ping", callback_data[:method]) - assert(callback_data[:duration]) - end - - test "#handle reports exception and sets error when around_request raises" do - reported_exception = nil - reported_context = nil - callback_data = nil - - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, server_context) { - reported_exception = e - reported_context = server_context - } - configuration.instrumentation_callback = ->(data) { callback_data = data.dup } - configuration.around_request = ->(_data, &_request_handler) { raise "around_request failure" } - - server = Server.new(name: "test_server", configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "ping", - id: 1, - } - - response = server.handle(request) - - assert_equal("around_request failure", reported_exception.message) - assert_equal({ request: request }, reported_context) - assert_equal(:internal_error, callback_data[:error]) - assert_equal(JsonRpcHandler::ErrorCode::INTERNAL_ERROR, response[:error][:code]) - end - - test "#handle does not double-report exception_reporter when a tool handler raises" do - report_count = 0 - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(_e, _server_context) { report_count += 1 } - - failing_tool = Tool.define(name: "failing_tool", description: "Always fails") do - raise "tool failure" - end - - server = Server.new(name: "test_server", tools: [failing_tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "failing_tool", arguments: {} }, - id: 1, - } - - server.handle(request) - - assert_equal(1, report_count) - end - - test "#handle reports both exceptions when around_request ensure raises after tool failure" do - reported = [] - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - configuration.around_request = ->(_data, &request_handler) do - request_handler.call - ensure - raise "around ensure boom" - end - - failing_tool = Tool.define(name: "failing_tool", description: "Always fails") do - raise "tool failure" - end - - server = Server.new(name: "test_server", tools: [failing_tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "failing_tool", arguments: {} }, - id: 1, - } - - response = server.handle(request) - - assert_equal(["tool failure", "around ensure boom"], reported) - assert_equal(JsonRpcHandler::ErrorCode::INTERNAL_ERROR, response[:error][:code]) - assert_nil(response[:error][:data]) - end - - test "#handle reports the same exception object reused across requests on every call" do - reported = [] - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, _server_context) { reported << e } - - shared_error = RuntimeError.new("reused") - shared_tool = Tool.define(name: "shared_failing_tool", description: "Always fails") do - raise shared_error - end - - server = Server.new(name: "test_server", tools: [shared_tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "shared_failing_tool", arguments: {} }, - id: 1, - } - - server.handle(request) - server.handle(request) - - assert_equal(2, reported.size) - assert_same(shared_error, reported[0]) - assert_same(shared_error, reported[1]) - end - - test "#handle reports frozen exceptions raised by tool handlers without wrapping them" do - reported = [] - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, _server_context) { reported << e } - - frozen_error = RuntimeError.new("frozen failure").freeze - frozen_tool = Tool.define(name: "frozen_tool", description: "Raises frozen") do - raise frozen_error - end - - server = Server.new(name: "test_server", tools: [frozen_tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "frozen_tool", arguments: {} }, - id: 1, - } - - response = server.handle(request) - - assert_equal([frozen_error], reported) - assert_equal("Internal error calling tool frozen_tool", response[:error][:data]) - end - - test "#handle still reports via exception_reporter when around_request swallows the tool failure" do - reported = [] - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - configuration.around_request = ->(_data, &request_handler) do - request_handler.call - rescue StandardError - { swallowed: true } - end - - failing_tool = Tool.define(name: "failing_tool", description: "Always fails") do - raise "tool failure" - end - - server = Server.new(name: "test_server", tools: [failing_tool], configuration: configuration) - - request = { - jsonrpc: "2.0", - method: "tools/call", - params: { name: "failing_tool", arguments: {} }, - id: 1, - } - - response = server.handle(request) - - assert_equal(["tool failure"], reported) - assert_equal({ swallowed: true }, response[:result]) - end - - test "#handle concurrent requests on a shared server report exceptions independently" do - reported = Queue.new - configuration = MCP::Configuration.new - configuration.exception_reporter = ->(e, _server_context) { reported << e.message } - - failing_tool = Tool.define(name: "concurrent_tool", description: "Raises per-thread") do |i:| - raise "thread #{i}" - end - - server = Server.new(name: "test_server", tools: [failing_tool], configuration: configuration) - - threads = 10.times.map do |i| - Thread.new do - server.handle({ - jsonrpc: "2.0", - method: "tools/call", - params: { name: "concurrent_tool", arguments: { i: i } }, - id: i, - }) - end - end - threads.each(&:join) - - messages = [] - messages << reported.pop until reported.empty? - - assert_equal(10.times.map { |i| "thread #{i}" }.sort, messages.sort) - end - test "#define_custom_method raises an error if the method is already defined" do assert_raises(Server::MethodAlreadyDefinedError) do @server.define_custom_method(method_name: "tools/call") do @@ -2235,16 +856,15 @@ module MCP assert_equal local_exception_reporter, server.configuration.exception_reporter end - test "server uses the latest handshake version when not configured" do + test "server uses default protocol version when not configured" do request = { jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = @server.handle(request) - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, response[:result][:protocolVersion] + assert_equal Configuration::LATEST_STABLE_PROTOCOL_VERSION, response[:result][:protocolVersion] end test "server response does not include optional parameters when configured" do @@ -2253,7 +873,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2269,7 +888,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2283,7 +901,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2296,7 +913,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2312,7 +928,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) expected_icons = [{ mimeType: "image/png", sizes: ["48x48"], src: "https://example.com", theme: "light" }] @@ -2326,7 +941,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2339,7 +953,6 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params, } response = server.handle(request) @@ -2454,58 +1067,6 @@ module MCP assert_equal("Error occurred in Test resource. `title` is not supported in protocol version 2025-03-26 or earlier", exception.message) end - test "raises error if `title` of class-based resource is used with protocol version 2025-03-26" do - configuration = Configuration.new(protocol_version: "2025-03-26") - - resource = Resource.define( - uri: "https://test_resource.invalid", - name: "test-resource", - title: "Test resource", - ) - exception = assert_raises(ArgumentError) do - Server.new(name: "test_server", resources: [resource], configuration: configuration) - end - assert_equal("Error occurred in Test resource. `title` is not supported in protocol version 2025-03-26 or earlier", exception.message) - end - - test "allows `$ref` in tool input schema with protocol version 2025-11-25" do - tool = Tool.define( - name: "ref_tool", - description: "Tool with $ref", - input_schema: { - type: "object", - "$defs": { address: { type: "object", properties: { city: { type: "string" } } } }, - properties: { address: { "$ref": "#/$defs/address" } }, - }, - ) - configuration = Configuration.new(protocol_version: "2025-11-25") - - assert_nothing_raised do - Server.new(name: "test_server", tools: [tool], configuration: configuration) - end - end - - test "raises error if `$ref` in tool input schema is used with protocol version 2025-06-18" do - tool = Tool.define( - name: "ref_tool", - description: "Tool with $ref", - input_schema: { - type: "object", - "$defs": { address: { type: "object", properties: { city: { type: "string" } } } }, - properties: { address: { "$ref": "#/$defs/address" } }, - }, - ) - configuration = Configuration.new(protocol_version: "2025-06-18") - - exception = assert_raises(ArgumentError) do - Server.new(name: "test_server", tools: [tool], configuration: configuration) - end - assert_equal( - "Error occurred in ref_tool. `$ref` in input schemas is supported by protocol version 2025-11-25 or higher", - exception.message, - ) - end - test "raises error if `title` of resource template is used with protocol version 2025-03-26" do configuration = Configuration.new(protocol_version: "2025-03-26") @@ -2525,16 +1086,11 @@ module MCP name: "defined_tool", description: "Defined tool", input_schema: { type: "object", properties: { message: { type: "string" } }, required: ["message"] }, - output_schema: { type: "object", properties: { response: { type: "string" } }, required: ["response"] }, meta: { foo: "bar" }, ) do |message:| - Tool::Response.new({ "response" => message }) + Tool::Response.new(message) end - stored_tool = @server.tools["defined_tool"] - assert_not_nil(stored_tool) - assert_equal(MCP::Tool::OutputSchema.new({ type: "object", properties: { response: { type: "string" } }, required: ["response"] }), stored_tool.output_schema) - response = @server.handle({ jsonrpc: "2.0", method: "tools/call", @@ -2542,7 +1098,7 @@ module MCP id: 1, }) - assert_equal({ content: { "response" => "success" }, isError: false }, response[:result]) + assert_equal({ content: "success", isError: false }, response[:result]) end test "#define_tool adds a tool with duplicated tool name to the server" do @@ -2613,114 +1169,18 @@ module MCP jsonrpc: "2.0", method: "initialize", id: 1, - params: initialize_params(protocolVersion: "1999-01-01"), } response = server.handle(request) assert_equal custom_version, response[:result][:protocolVersion] end - test "server negotiates protocol version when client requests a supported version" do - server = Server.new(name: "test_server") - - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2025-06-18"), - } - - response = server.handle(request) - assert_equal "2025-06-18", response[:result][:protocolVersion] - end - - test "server falls back to the latest handshake version when client requests unsupported version" do - server = Server.new(name: "test_server") - - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "1999-01-01"), - } - - response = server.handle(request) - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, response[:result][:protocolVersion] - end - - test "server counter-offers 2025-11-25 when the client requests 2026-07-28 via initialize" do - # Per the SEP-2575 era model, `initialize` negotiates legacy versions only: a modern version carries - # its own version on every request and has no handshake at all. The TypeScript and Python servers - # answer the same way. - server = Server.new(name: "test_server") - - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2026-07-28"), - } - - response = server.handle(request) - assert_equal "2025-11-25", response[:result][:protocolVersion] - end - - test "server removes description and icons from server_info when negotiating to 2025-06-18" do + test "tools/call handles missing arguments field" do server = Server.new( - name: "test_server", - description: "A test server", - icons: [Icon.new(src: "https://example.com/icon.png")], + tools: [TestTool], + configuration: Configuration.new(validate_tool_call_arguments: true), ) - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2025-06-18"), - } - - response = server.handle(request) - assert_equal "2025-06-18", response[:result][:protocolVersion] - refute response[:result][:serverInfo].key?(:description) - refute response[:result][:serverInfo].key?(:icons) - end - - test "server removes title and websiteUrl when negotiating to 2025-03-26" do - server = Server.new(name: "test_server", title: "Test Server", website_url: "https://example.com") - - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2025-03-26"), - } - - response = server.handle(request) - assert_equal "2025-03-26", response[:result][:protocolVersion] - refute response[:result][:serverInfo].key?(:title) - refute response[:result][:serverInfo].key?(:websiteUrl) - end - - test "server removes instructions when negotiating to 2024-11-05" do - server = Server.new(name: "test_server", instructions: "Some instructions") - - request = { - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: initialize_params(protocolVersion: "2024-11-05"), - } - - response = server.handle(request) - assert_equal "2024-11-05", response[:result][:protocolVersion] - refute response[:result].key?(:instructions) - end - - test "tools/call returns tool execution error for missing arguments" do - configuration = Configuration.new(validate_tool_call_arguments: true) - configuration.instrumentation_callback = instrumentation_helper.callback - server = Server.new(tools: [TestTool], configuration: configuration) - response = server.handle( { jsonrpc: "2.0", @@ -2734,22 +1194,16 @@ module MCP assert_equal "2.0", response[:jsonrpc] assert_equal 1, response[:id] - assert_nil response[:error] - assert(response[:result][:isError]) - assert_equal "text", response[:result][:content][0][:type] + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] assert_includes response[:result][:content][0][:text], "Missing required arguments" - assert_instrumentation_data({ - method: "tools/call", - tool_name: "test_tool", - tool_arguments: {}, - error: :missing_required_arguments, - }) end - test "tools/call returns tool execution error for invalid arguments when validate_tool_call_arguments is true" do - configuration = Configuration.new(validate_tool_call_arguments: true) - configuration.instrumentation_callback = instrumentation_helper.callback - server = Server.new(tools: [TestTool], configuration: configuration) + test "tools/call validates arguments against input schema when validate_tool_call_arguments is true" do + server = Server.new( + tools: [TestTool], + configuration: Configuration.new(validate_tool_call_arguments: true), + ) response = server.handle( { @@ -2765,43 +1219,8 @@ module MCP assert_equal "2.0", response[:jsonrpc] assert_equal 1, response[:id] - assert_nil response[:error] - assert(response[:result][:isError]) - assert_equal "text", response[:result][:content][0][:type] - assert_includes response[:result][:content][0][:text], "Invalid arguments" - assert_instrumentation_data({ - method: "tools/call", - tool_name: "test_tool", - tool_arguments: { message: 123 }, - error: :invalid_schema, - }) - end - - test "tools/call returns tool execution error for nested schema validation failure" do - server = Server.new( - tools: [ComplexTypesTool], - configuration: Configuration.new(validate_tool_call_arguments: true), - ) - - response = server.handle( - { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "complex_types_tool", - arguments: { - numbers: [1, 2, 3], - strings: ["a", "b", "c"], - objects: [{ name: 123 }], - }, - }, - }, - ) - - assert_nil response[:error] - assert(response[:result][:isError]) - assert_equal "text", response[:result][:content][0][:type] + assert_nil response[:error], "Expected no JSON-RPC error" + assert response[:result][:isError] assert_includes response[:result][:content][0][:text], "Invalid arguments" end @@ -2887,7 +1306,7 @@ module MCP assert_equal "OK", response[:result][:content][0][:content] end - test "tools/call returns tool execution error when additionalProperties set to false" do + test "tools/call disallows additional properties when additionalProperties set to false" do server = Server.new( tools: [TestToolWithAdditionalPropertiesSetToFalse], configuration: Configuration.new(validate_tool_call_arguments: true), @@ -2910,923 +1329,9 @@ module MCP assert_equal "2.0", response[:jsonrpc] assert_equal 1, response[:id] - assert_nil response[:error] - assert(response[:result][:isError]) - assert_equal "text", response[:result][:content][0][:type] - assert_includes response[:result][:content][0][:text], "Invalid arguments" - end - - test "tools/call skips output schema validation by default" do - tool = Tool.define( - name: "invalid_structured_content_tool", - output_schema: { - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, - ) do - Tool::Response.new( - [{ type: "text", text: "ok" }], - structured_content: { result: 123 }, - ) - end - server = Server.new(tools: [tool]) - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "invalid_structured_content_tool" }, - }) - - assert_nil response[:error] - assert_equal({ result: 123 }, response[:result][:structuredContent]) - end - - test "tools/call validates structuredContent against output schema when enabled" do - tool = Tool.define( - name: "valid_structured_content_tool", - output_schema: { - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, - ) do - Tool::Response.new( - [{ type: "text", text: "ok" }], - structured_content: { result: "success" }, - ) - end - server = Server.new( - tools: [tool], - configuration: Configuration.new(validate_tool_call_results: true), - ) - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "valid_structured_content_tool" }, - }) - - assert_nil response[:error] - assert_equal({ result: "success" }, response[:result][:structuredContent]) - end - - test "tools/call returns JSON-RPC error for invalid structuredContent when output schema validation is enabled" do - tool = Tool.define( - name: "invalid_structured_content_tool", - output_schema: { - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, - ) do - Tool::Response.new( - [{ type: "text", text: "ok" }], - structured_content: { result: 123 }, - ) - end - server = Server.new( - tools: [tool], - configuration: Configuration.new(validate_tool_call_results: true), - ) - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "invalid_structured_content_tool" }, - }) - - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool invalid_structured_content_tool", response[:error][:data] - end - - test "tools/call returns JSON-RPC error when output schema validation is enabled and structuredContent is missing" do - tool = Tool.define( - name: "missing_structured_content_tool", - output_schema: { - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, - ) do - Tool::Response.new([{ type: "text", text: "ok" }]) - end - server = Server.new( - tools: [tool], - configuration: Configuration.new(validate_tool_call_results: true), - ) - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "missing_structured_content_tool" }, - }) - - assert_nil response[:result] - assert_equal(-32603, response[:error][:code]) - assert_equal "Internal error", response[:error][:message] - assert_equal "Internal error calling tool missing_structured_content_tool", response[:error][:data] - end - - test "tools/call skips output schema validation for error responses" do - tool = Tool.define( - name: "error_response_tool", - output_schema: { - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, - ) do - Tool::Response.new( - [{ type: "text", text: "failed" }], - error: true, - structured_content: { result: 123 }, - ) - end - server = Server.new( - tools: [tool], - configuration: Configuration.new(validate_tool_call_results: true), - ) - - response = server.handle({ - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { name: "error_response_tool" }, - }) - - assert_nil response[:error] + assert_nil response[:error], "Expected no JSON-RPC error" assert response[:result][:isError] - assert_equal({ result: 123 }, response[:result][:structuredContent]) - end - - test "tools/call returns JSON-RPC -32602 protocol error when tool is not found" do - server = Server.new( - tools: [TestTool], - ) - - response = server.handle( - { - jsonrpc: "2.0", - id: 1, - method: "tools/call", - params: { - name: "unknown_tool", - arguments: {}, - }, - }, - ) - - assert_nil response[:result] - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - assert_includes response[:error][:data], "Tool not found: unknown_tool" - end - - test "#handle completion/complete returns default completion result" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: { completion: { values: [], hasMore: false } }, - }, - response, - ) - end - - test "#handle completion/complete with custom handler for ref/prompt" do - prompt = Prompt.define( - name: "code_review", - arguments: [Prompt::Argument.new(name: "language", required: true)], - ) {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - { completion: { values: ["python", "pytorch", "pyside"], total: 10, hasMore: true } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "code_review" }, - argument: { name: "language", value: "py" }, - }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: { completion: { values: ["python", "pytorch", "pyside"], total: 10, hasMore: true } }, - }, - response, - ) - end - - test "#handle completion/complete with custom handler for ref/resource" do - template = ResourceTemplate.new( - uri_template: "file:///{path}", - name: "file", - ) - server = Server.new( - name: "test_server", - resource_templates: [template], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - { completion: { values: ["file:///src", "file:///spec"], hasMore: false } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/resource", uri: "file:///{path}" }, - argument: { name: "path", value: "s" }, - }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: { completion: { values: ["file:///src", "file:///spec"], hasMore: false } }, - }, - response, - ) - end - - test "#handle completion/complete passes context arguments to handler" do - prompt = Prompt.define( - name: "code_review", - arguments: [ - Prompt::Argument.new(name: "language", required: true), - Prompt::Argument.new(name: "framework", required: false), - ], - ) {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - received_params = nil - server.completion_handler do |params| - received_params = params - { completion: { values: ["flask"], hasMore: false } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "code_review" }, - argument: { name: "framework", value: "fla" }, - context: { arguments: { language: "python" } }, - }, - }) - - assert_equal({ language: "python" }, received_params.dig(:context, :arguments)) - end - - test "#handle completion/complete truncates values exceeding 100 items" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - { completion: { values: (1..150).map(&:to_s), hasMore: false } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "" }, - }, - }) - - completion = response[:result][:completion] - assert_equal 100, completion[:values].length - assert_equal "1", completion[:values].first - assert_equal "100", completion[:values].last - assert(completion[:hasMore]) - assert_equal 150, completion[:total] - end - - test "#handle completion/complete returns error for nonexistent prompt" do - server = Server.new( - name: "test_server", - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "nonexistent" }, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete returns error for nonexistent resource template" do - server = Server.new( - name: "test_server", - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/resource", uri: "unknown://template" }, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete resource-not-found error carries the uri in error data" do - server = Server.new( - name: "test_server", - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/resource", uri: "unknown://template" }, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal(-32602, response[:error][:code]) - assert_equal("Resource not found: unknown://template", response[:error][:message]) - assert_equal({ uri: "unknown://template" }, response[:error][:data]) - end - - test "#handle completion/complete returns error for invalid ref type" do - server = Server.new( - name: "test_server", - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/invalid" }, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete returns error for missing ref" do - server = Server.new( - name: "test_server", - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: {}, - argument: { name: "arg", value: "val" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete with custom handler for ref/resource with resource URI" do - resource = Resource.new( - uri: "file:///README.md", - name: "readme", - ) - server = Server.new( - name: "test_server", - resources: [resource], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - { completion: { values: ["file:///README.md"], hasMore: false } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/resource", uri: "file:///README.md" }, - argument: { name: "path", value: "R" }, - }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: { completion: { values: ["file:///README.md"], hasMore: false } }, - }, - response, - ) - end - - test "#handle completion/complete returns error for missing argument" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete returns error for missing argument value" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg" }, - }, - }) - - assert_equal(-32_602, response[:error][:code]) - end - - test "#handle completion/complete returns default when handler returns nil" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - nil - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "" }, - }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: { completion: { values: [], hasMore: false } }, - }, - response, - ) - end - - test "#handle completion/complete with string-keyed handler result" do - prompt = Prompt.define(name: "test") {} - server = Server.new( - name: "test_server", - prompts: [prompt], - capabilities: { completions: {} }, - ) - - server.completion_handler do |_params| - { "completion" => { "values" => ["alpha", "beta"], "hasMore" => true } } - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "" }, - }, - }) - - assert_equal ["alpha", "beta"], response[:result][:completion][:values] - assert response[:result][:completion][:hasMore] - end - - test "#handle completion/complete returns invalid params for non-Hash params" do - server = Server.new( - name: "test_server", - prompts: [], - capabilities: { completions: {} }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: "invalid", - }) - - assert_equal(-32602, response[:error][:code]) - end - - test "#handle completion/complete returns error when completions capability is not declared" do - server = Server.new( - name: "test_server", - prompts: [], - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "completion/complete", - params: { - ref: { type: "ref/prompt", name: "test" }, - argument: { name: "arg", value: "" }, - }, - }) - - assert response[:error] - assert_includes response[:error][:data], "completions" - end - - test "#handle resources/subscribe returns empty result" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/subscribe", - params: { uri: "https://example.com/resource" }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: {}, - }, - response, - ) - end - - test "#handle resources/unsubscribe returns empty result" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/unsubscribe", - params: { uri: "https://example.com/resource" }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: {}, - }, - response, - ) - end - - test "#handle resources/subscribe with custom handler calls the handler" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - received_params = nil - server.resources_subscribe_handler do |params| - received_params = params - {} - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/subscribe", - params: { uri: "https://example.com/resource" }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: {}, - }, - response, - ) - assert_equal "https://example.com/resource", received_params[:uri] - end - - test "#handle resources/unsubscribe with custom handler calls the handler" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - received_params = nil - server.resources_unsubscribe_handler do |params| - received_params = params - {} - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/unsubscribe", - params: { uri: "https://example.com/resource" }, - }) - - assert_equal( - { - jsonrpc: "2.0", - id: 2, - result: {}, - }, - response, - ) - assert_equal "https://example.com/resource", received_params[:uri] - end - - test "#handle resources/subscribe without uri returns -32602" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/subscribe", - params: {}, - }) - - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - assert_includes response[:error][:data], "uri" - end - - test "#handle resources/unsubscribe without uri returns -32602" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/unsubscribe", - params: {}, - }) - - assert_equal(-32602, response[:error][:code]) - assert_equal "Invalid params", response[:error][:message] - end - - # Builds an initialized server that advertises the `resources.subscribe` capability. - def subscription_server - server = Server.new(name: "test_server", capabilities: { resources: { subscribe: true } }) - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - server - end - - # Sends `method` (`resources/subscribe` or `resources/unsubscribe`) and returns the JSON-RPC result. - def handle_subscription(server, method) - server.handle({ - jsonrpc: "2.0", - id: 2, - method: method, - params: { uri: "https://example.com/resource" }, - })[:result] - end - - test "#handle resources/subscribe passes a handler-returned _meta through to the result" do - server = subscription_server - server.resources_subscribe_handler { |_params| { _meta: { "acme.example/subscriptionId" => "sub-1" } } } - - result = handle_subscription(server, "resources/subscribe") - - assert_equal({ _meta: { "acme.example/subscriptionId" => "sub-1" } }, result) - end - - test "#handle resources/unsubscribe passes a handler-returned _meta through to the result" do - server = subscription_server - server.resources_unsubscribe_handler { |_params| { _meta: { "acme.example/note" => "gone" } } } - - result = handle_subscription(server, "resources/unsubscribe") - - assert_equal({ _meta: { "acme.example/note" => "gone" } }, result) - end - - test "#handle resources/subscribe drops a handler-returned field that is not _meta" do - # The spec's result defines no member other than `_meta`, so a top-level field the handler adds is not - # a subscription protocol; it stays out of the response. - server = subscription_server - server.resources_subscribe_handler { |_params| { subscriptionId: "sub-1" } } - - result = handle_subscription(server, "resources/subscribe") - - assert_equal({}, result) - end - - test "#handle resources/subscribe accepts a string _meta key from the handler" do - server = subscription_server - server.resources_subscribe_handler { |_params| { "_meta" => { "k" => "v" } } } - - result = handle_subscription(server, "resources/subscribe") - - assert_equal({ _meta: { "k" => "v" } }, result) - end - - test "#handle resources/subscribe ignores a handler-returned _meta that is not a hash" do - server = subscription_server - server.resources_subscribe_handler { |_params| { _meta: "not-a-hash" } } - - result = handle_subscription(server, "resources/subscribe") - - assert_equal({}, result) - end - - test "#handle resources/subscribe keeps an empty result when the handler returns a non-hash" do - server = subscription_server - server.resources_subscribe_handler { |_params| nil } - - result = handle_subscription(server, "resources/subscribe") - - assert_equal({}, result) - end - - test "#handle resources/subscribe without uri does not invoke a custom handler" do - server = Server.new( - name: "test_server", - capabilities: { resources: { subscribe: true } }, - ) - - handler_called = false - server.resources_subscribe_handler do |_params| - handler_called = true - {} - end - - server.handle({ jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params }) - server.handle({ jsonrpc: "2.0", method: "notifications/initialized" }) - - response = server.handle({ - jsonrpc: "2.0", - id: 2, - method: "resources/subscribe", - params: {}, - }) - - assert_equal(-32602, response[:error][:code]) - refute handler_called + assert_includes response[:result][:content][0][:text], "Invalid arguments" end test "tools/call with no args" do @@ -3901,666 +1406,5 @@ module MCP end end end - - class JsonObjectValue - def initialize(value) - @value = value - end - - def to_json(*args) - @value.to_json(*args) - end - end - - test "server_context_with_meta uses accessor method, not ivar directly" do - subclass = Class.new(Server) do - def server_context - { custom: "from_accessor" } - end - end - - server = subclass.new(name: "test", tools: []) - - received_context = nil - server.define_tool(name: "ctx_tool") do |server_context:| - received_context = server_context - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - request = { - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "ctx_tool", arguments: {} }, - } - - server.handle(request) - assert_equal "from_accessor", received_context[:custom] - end - - test "#handle tools/call passes W3C trace context _meta keys through to the handler" do - # Per SEP-414, `traceparent`, `tracestate`, and `baggage` are reserved - # un-prefixed `_meta` keys and must never be stripped by the SDK. - server = Server.new(name: "trace_test", tools: []) - received_context = nil - server.define_tool(name: "trace_tool") do |server_context:| - received_context = server_context - Tool::Response.new([{ type: "text", text: "ok" }]) - end - - server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { - name: "trace_tool", - arguments: {}, - _meta: { - traceparent: "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01", - tracestate: "vendor=value", - baggage: "userId=alice", - progressToken: "token-1", - }, - }, - }) - - meta = received_context[:_meta] - assert_equal "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01", meta[:traceparent] - assert_equal "vendor=value", meta[:tracestate] - assert_equal "userId=alice", meta[:baggage] - assert_equal "token-1", meta[:progressToken] - end - - test "#handle prompts/get passes W3C trace context _meta keys through to the handler" do - server = Server.new(name: "trace_test", prompts: []) - received_context = nil - server.define_prompt(name: "trace_prompt", arguments: []) do |_args, server_context:| - received_context = server_context - Prompt::Result.new( - description: "a prompt description", - messages: [Prompt::Message.new(role: "user", content: Content::Text.new("a prompt message"))], - ) - end - - server.handle({ - jsonrpc: "2.0", - method: "prompts/get", - id: 1, - params: { - name: "trace_prompt", - arguments: {}, - _meta: { - traceparent: "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01", - tracestate: "vendor=value", - baggage: "userId=alice", - }, - }, - }) - - meta = received_context[:_meta] - MCP::TraceContext::META_KEYS.each do |key| - assert meta.key?(key.to_sym), "expected _meta to retain #{key}" - end - end - - test "#handle tools/call mirrors non-object structuredContent when content is omitted or nil" do - # Per SEP-2106, `structuredContent` may be any JSON value. Older clients may only read `content`, - # so the server adds a serialized fallback when the tool provided no content blocks. - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "nil_content_tool") do - Tool::Response.new(nil, structured_content: [1, 2]) - end - server.define_tool(name: "omitted_content_tool") do - Tool::Response.new(structured_content: [1, 2]) - end - - ["nil_content_tool", "omitted_content_tool"].each_with_index do |tool_name, index| - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: index + 1, - params: { name: tool_name, arguments: {} }, - }) - - assert_equal [1, 2], response.dig(:result, :structuredContent) - assert_equal [{ type: "text", text: "[1,2]" }], response.dig(:result, :content) - end - end - - test "#handle tools/call does not overwrite explicit content when structuredContent is non-object" do - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "array_tool") do - Tool::Response.new([{ type: "text", text: "two items" }], structured_content: [1, 2]) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "array_tool", arguments: {} }, - }) - - assert_equal [{ type: "text", text: "two items" }], response.dig(:result, :content) - end - - test "#handle tools/call leaves object structuredContent without a text fallback" do - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "object_tool") do - Tool::Response.new(nil, structured_content: { answer: 42 }) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "object_tool", arguments: {} }, - }) - - assert_equal({ answer: 42 }, response.dig(:result, :structuredContent)) - assert_empty response.dig(:result, :content) - end - - test "#handle tools/call recognizes object-like structuredContent by its JSON shape" do - structured_content = JsonObjectValue.new(answer: 42) - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "object_tool") do - Tool::Response.new(nil, structured_content: structured_content) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "object_tool", arguments: {} }, - }) - - assert_equal structured_content, response.dig(:result, :structuredContent) - assert_empty response.dig(:result, :content) - end - - test "#handle tools/call preserves explicit empty content for non-object structuredContent" do - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "array_tool") do - Tool::Response.new([], structured_content: [1, 2]) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "array_tool", arguments: {} }, - }) - - assert_equal [1, 2], response.dig(:result, :structuredContent) - assert_empty response.dig(:result, :content) - end - - test "#handle tools/call preserves explicit empty content for object-like structuredContent" do - structured_content = JsonObjectValue.new(answer: 42) - - server = Server.new(name: "structured_test", tools: []) - server.define_tool(name: "object_tool") do - Tool::Response.new([], structured_content: structured_content) - end - - response = server.handle({ - jsonrpc: "2.0", - method: "tools/call", - id: 1, - params: { name: "object_tool", arguments: {} }, - }) - - assert_equal structured_content, response.dig(:result, :structuredContent) - assert_empty response.dig(:result, :content) - end - - test "list results carry ttlMs and cacheScope when ttl_ms is configured" do - # SEP-2549 cache hints. The unset cacheScope fills as "private", the side that cannot - # leak a user-dependent result through a shared cache, matching the TypeScript and - # Python SDK defaults (the spec names no default scope). - server = Server.new(name: "ttl_test", ttl_ms: 5000) - - ["tools/list", "prompts/list", "resources/list", "resources/templates/list"].each_with_index do |method, index| - result = server.handle({ jsonrpc: "2.0", method: method, id: index + 1 })[:result] - - assert_equal 5000, result[:ttlMs], "#{method} missing ttlMs" - assert_equal "private", result[:cacheScope], "#{method} missing cacheScope" - end - end - - test "resources/read carries cache hints when cache_scope is configured" do - # The ttlMs default is 0 (do not cache), the only universally safe value. - server = Server.new(name: "ttl_test", cache_scope: "private") - - result = server.handle({ - jsonrpc: "2.0", - method: "resources/read", - id: 1, - params: { uri: "file:///x" }, - })[:result] - - assert_equal 0, result[:ttlMs] - assert_equal "private", result[:cacheScope] - end - - test "results omit cache hints when ttl_ms and cache_scope are not configured" do - # Wire-format regression: opt-in emission keeps default output unchanged. - list_result = @server.handle({ jsonrpc: "2.0", method: "tools/list", id: 1 })[:result] - read_result = @server.handle({ - jsonrpc: "2.0", - method: "resources/read", - id: 2, - params: { uri: "file:///x" }, - })[:result] - - refute list_result.key?(:ttlMs) - refute list_result.key?(:cacheScope) - refute read_result.key?(:ttlMs) - refute read_result.key?(:cacheScope) - end - - test "cache hints appear alongside nextCursor when paginating" do - tool_a = Tool.define(name: "tool_a", description: "Tool A") - tool_b = Tool.define(name: "tool_b", description: "Tool B") - server = Server.new(name: "ttl_test", tools: [tool_a, tool_b], page_size: 1, ttl_ms: 1000, cache_scope: "private") - - result = server.handle({ jsonrpc: "2.0", method: "tools/list", id: 1 })[:result] - - assert_not_nil result[:nextCursor] - assert_equal 1000, result[:ttlMs] - assert_equal "private", result[:cacheScope] - end - - test "a resources_read_handler can override the server-level cache hints per result" do - server = Server.new(name: "ttl_test", ttl_ms: 5000) - server.resources_read_handler do |params| - { contents: [{ uri: params[:uri], mimeType: "text/plain", text: "hi" }], ttlMs: 60_000 } - end - - result = server.handle({ - jsonrpc: "2.0", - method: "resources/read", - id: 1, - params: { uri: "file:///x" }, - })[:result] - - assert_equal 60_000, result[:ttlMs] - assert_equal "private", result[:cacheScope] - assert_equal [{ uri: "file:///x", mimeType: "text/plain", text: "hi" }], result[:contents] - end - - test "ttl_ms and cache_scope writers reject invalid values" do - assert_raises(ArgumentError) { Server.new(name: "ttl_test", ttl_ms: -1) } - assert_raises(ArgumentError) { Server.new(name: "ttl_test", ttl_ms: 1.5) } - assert_raises(ArgumentError) { Server.new(name: "ttl_test", cache_scope: "internal") } - end - - test "#handle tools/list returns paginated results when page_size is set" do - tool_a = Tool.define(name: "tool_a", title: "Tool A", description: "Tool A") - tool_b = Tool.define(name: "tool_b", title: "Tool B", description: "Tool B") - tool_c = Tool.define(name: "tool_c", title: "Tool C", description: "Tool C") - - server = Server.new( - name: "pagination_test", - tools: [tool_a, tool_b, tool_c], - page_size: 2, - ) - - first_request = { jsonrpc: "2.0", method: "tools/list", id: 1 } - first_response = server.handle(first_request) - first_result = first_response[:result] - - assert_equal 2, first_result[:tools].size - assert_equal "tool_a", first_result[:tools][0][:name] - assert_equal "tool_b", first_result[:tools][1][:name] - assert_not_nil first_result[:nextCursor] - - second_request = { jsonrpc: "2.0", method: "tools/list", id: 2, params: { cursor: first_result[:nextCursor] } } - second_response = server.handle(second_request) - second_result = second_response[:result] - - assert_equal 1, second_result[:tools].size - assert_equal "tool_c", second_result[:tools][0][:name] - # Final page omits the nextCursor key entirely (not just sets it to nil). - refute second_result.key?(:nextCursor) - end - - test "#handle tools/list returns all tools when page_size is not set" do - response = @server.handle({ jsonrpc: "2.0", method: "tools/list", id: 1 }) - result = response[:result] - - assert_kind_of Array, result[:tools] - assert_nil result[:nextCursor] - end - - test "#handle tools/list returns error for invalid cursor" do - server = Server.new(name: "pagination_test", tools: [@tool], page_size: 1) - - request = { jsonrpc: "2.0", method: "tools/list", id: 1, params: { cursor: "!!!invalid!!!" } } - response = server.handle(request) - - assert_not_nil response[:error] - assert_equal(-32602, response[:error][:code]) - end - - test "#handle prompts/list returns paginated results when page_size is set" do - prompt_a = Prompt.define(name: "prompt_a", title: "Prompt A", description: "A") { Prompt::Result.new(description: "A", messages: []) } - prompt_b = Prompt.define(name: "prompt_b", title: "Prompt B", description: "B") { Prompt::Result.new(description: "B", messages: []) } - - server = Server.new(name: "pagination_test", prompts: [prompt_a, prompt_b], page_size: 1) - - first_response = server.handle({ jsonrpc: "2.0", method: "prompts/list", id: 1 }) - first_result = first_response[:result] - - assert_equal 1, first_result[:prompts].size - assert_equal "prompt_a", first_result[:prompts][0][:name] - assert_not_nil first_result[:nextCursor] - - second_response = server.handle({ jsonrpc: "2.0", method: "prompts/list", id: 2, params: { cursor: first_result[:nextCursor] } }) - second_result = second_response[:result] - - assert_equal 1, second_result[:prompts].size - assert_equal "prompt_b", second_result[:prompts][0][:name] - assert_nil second_result[:nextCursor] - end - - test "#handle resources/list returns paginated results when page_size is set" do - resource_a = Resource.new(uri: "https://a.invalid", name: "a", description: "A", mime_type: "text/plain") - resource_b = Resource.new(uri: "https://b.invalid", name: "b", description: "B", mime_type: "text/plain") - - server = Server.new(name: "pagination_test", resources: [resource_a, resource_b], page_size: 1) - - first_response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 1 }) - first_result = first_response[:result] - - assert_equal 1, first_result[:resources].size - assert_equal "a", first_result[:resources][0][:name] - assert_not_nil first_result[:nextCursor] - - second_response = server.handle({ jsonrpc: "2.0", method: "resources/list", id: 2, params: { cursor: first_result[:nextCursor] } }) - second_result = second_response[:result] - - assert_equal 1, second_result[:resources].size - assert_equal "b", second_result[:resources][0][:name] - assert_nil second_result[:nextCursor] - end - - test "Server.new raises ArgumentError when page_size is zero" do - assert_raises(ArgumentError) do - Server.new(name: "test", page_size: 0) - end - end - - test "Server.new raises ArgumentError when page_size is negative" do - assert_raises(ArgumentError) do - Server.new(name: "test", page_size: -1) - end - end - - test "Server.new raises ArgumentError when page_size is non-Integer" do - assert_raises(ArgumentError) do - Server.new(name: "test", page_size: "10") - end - end - - test "page_size= raises ArgumentError for invalid values" do - server = Server.new(name: "test") - - assert_raises(ArgumentError) { server.page_size = 0 } - assert_raises(ArgumentError) { server.page_size = -1 } - assert_raises(ArgumentError) { server.page_size = "5" } - - server.page_size = nil - server.page_size = 10 - assert_equal 10, server.page_size - end - - test "#handle tools/list returns -32602 for non-Hash params" do - server = Server.new(name: "test", tools: [@tool], page_size: 1) - - request = { jsonrpc: "2.0", method: "tools/list", id: 1, params: [1, 2, 3] } - response = server.handle(request) - - assert_not_nil response[:error] - assert_equal(-32602, response[:error][:code]) - end - - test "#handle_json tools/list returns -32602 for numeric cursor (spec requires string)" do - server = Server.new(name: "test", tools: [@tool], page_size: 1) - - request_json = '{"jsonrpc":"2.0","method":"tools/list","id":1,"params":{"cursor":0}}' - response = JSON.parse(server.handle_json(request_json), symbolize_names: true) - - assert_not_nil response[:error] - assert_equal(-32602, response[:error][:code]) - end - - test "#handle resources/templates/list returns paginated results when page_size is set" do - template_a = ResourceTemplate.new(uri_template: "https://a.invalid/{id}", name: "a", description: "A", mime_type: "text/plain") - template_b = ResourceTemplate.new(uri_template: "https://b.invalid/{id}", name: "b", description: "B", mime_type: "text/plain") - - server = Server.new(name: "pagination_test", resource_templates: [template_a, template_b], page_size: 1) - - first_response = server.handle({ jsonrpc: "2.0", method: "resources/templates/list", id: 1 }) - first_result = first_response[:result] - - assert_equal 1, first_result[:resourceTemplates].size - assert_equal "a", first_result[:resourceTemplates][0][:name] - assert_not_nil first_result[:nextCursor] - - second_response = server.handle({ jsonrpc: "2.0", method: "resources/templates/list", id: 2, params: { cursor: first_result[:nextCursor] } }) - second_result = second_response[:result] - - assert_equal 1, second_result[:resourceTemplates].size - assert_equal "b", second_result[:resourceTemplates][0][:name] - assert_nil second_result[:nextCursor] - end - - test "an MCP Apps server advertises the extension and serves ui:// templates" do - # SEP-1865: the extension rides the SEP-2133 `capabilities.extensions` machinery, - # UI templates are ordinary resources, and tools link to them via `_meta.ui.resourceUri`. - dashboard = Apps.ui_resource(uri: "ui://weather/dashboard", name: "weather_dashboard") - capabilities = Server::Capabilities.new - capabilities.support_tools - capabilities.support_resources - capabilities.support_extensions(Apps.capability) - server = Server.new(name: "apps_test", capabilities: capabilities, resources: [dashboard]) - server.define_tool( - name: "get_weather", - meta: Apps.tool_meta(resource_uri: "ui://weather/dashboard"), - ) do - Tool::Response.new([{ type: "text", text: "Sunny" }]) - end - - server.resources_read_handler do |params| - [{ uri: params[:uri], mimeType: Apps::RESOURCE_MIME_TYPE, text: "dashboard" }] - end - - init_response = server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - clientInfo: { name: "host", version: "1.0" }, - capabilities: { extensions: Apps.capability }, - }, - }) - - tools_response = server.handle({ - jsonrpc: "2.0", - method: "tools/list", - id: 2, - }) - - read_response = server.handle({ - jsonrpc: "2.0", - method: "resources/read", - id: 3, - params: { uri: "ui://weather/dashboard" }, - }) - - assert_equal( - { mimeTypes: [Apps::RESOURCE_MIME_TYPE] }, - init_response.dig(:result, :capabilities, :extensions, Apps::EXTENSION_ID), - ) - tool_entry = tools_response.dig(:result, :tools, 0) - - assert_equal "ui://weather/dashboard", tool_entry.dig(:_meta, :ui, :resourceUri) - assert_equal "dashboard", read_response.dig(:result, :contents, 0, :text) - # The server can gate the text-only fallback on the client's declaration. - assert Apps.client_supports?(server.client_capabilities) - end - - test "an MCP Apps tool falls back to text for clients without the extension" do - capabilities = Server::Capabilities.new - capabilities.support_extensions(Apps.capability) - server = Server.new(name: "apps_test", capabilities: capabilities) - - server.handle({ - jsonrpc: "2.0", - method: "initialize", - id: 1, - params: { - protocolVersion: "2025-11-25", - clientInfo: { name: "plain_client", version: "1.0" }, - capabilities: {}, - }, - }) - - refute Apps.client_supports?(server.client_capabilities) - end - - # SEP-2322 makes `resultType` REQUIRED on every result of a 2026-07-28 server; - # `"complete"` is the standard shape, and legacy results stay unstamped. - test "modern results carry resultType complete" do - server = Server.new(name: "result_type_test", tools: [result_type_tool]) - - # Every method here has to be one the modern lifecycle still has. `ping` does not qualify: - # SEP-2575 removed it, so a modern request naming it is answered with -32601, not a stamped result. - [ - modern_request(Methods::TOOLS_LIST, {}), - modern_request(Methods::PROMPTS_LIST, {}), - modern_request(Methods::TOOLS_CALL, { name: "result_type_tool", arguments: {} }), - ].each do |request| - response = server.handle(request) - assert_equal "complete", response.dig(:result, :resultType), "expected stamp for #{request[:method]}" - end - end - - test "legacy results carry no resultType" do - server = Server.new(name: "result_type_test", tools: [result_type_tool]) - - [ - { jsonrpc: "2.0", method: Methods::TOOLS_LIST, id: 1 }, - { jsonrpc: "2.0", method: Methods::PING, id: 2 }, - { jsonrpc: "2.0", method: Methods::TOOLS_CALL, id: 3, params: { name: "result_type_tool", arguments: {} } }, - ].each do |request| - response = server.handle(request) - refute response[:result].key?(:resultType), "expected no stamp for #{request[:method]}" - end - end - - test "results after a counter-offered modern initialize carry no resultType" do - # The scenario from issue #512: a client asking `initialize` for 2026-07-28 lands on - # 2025-11-25, where `resultType` does not exist, so its absence is the correct shape - # (clients MUST read an absent `resultType` as "complete" on that revision). - server = Server.new(name: "result_type_test", tools: [result_type_tool]) - session = ServerSession.new(server: server, transport: mock) - - init_response = server.handle( - { jsonrpc: "2.0", method: "initialize", id: 1, params: initialize_params(protocolVersion: "2026-07-28") }, - session: session, - ) - response = server.handle({ jsonrpc: "2.0", method: Methods::TOOLS_LIST, id: 2 }, session: session) - - assert_equal Configuration::LATEST_HANDSHAKE_PROTOCOL_VERSION, init_response.dig(:result, :protocolVersion) - refute response[:result].key?(:resultType) - end - - test "server/discover carries resultType complete" do - server = Server.new(name: "result_type_test", tools: [result_type_tool]) - - response = server.handle({ jsonrpc: "2.0", method: Methods::SERVER_DISCOVER, id: 1 }) - - assert_equal "complete", response.dig(:result, :resultType) - end - - # SEP-2549 makes the `ttlMs`/`cacheScope` cache hints REQUIRED on cacheable results at 2026-07-28; - # unset hints get the spec defaults, and stable protocol versions keep the opt-in emission. - test "modern cacheable results carry the default cache hints" do - server = Server.new(name: "cache_hints_test", tools: [result_type_tool]) - - response = server.handle(modern_request(Methods::TOOLS_LIST, {})) - - assert_equal 0, response.dig(:result, :ttlMs) - assert_equal "private", response.dig(:result, :cacheScope) - end - - test "modern non-cacheable results carry no cache hints" do - server = Server.new(name: "cache_hints_test", tools: [result_type_tool]) - - # `tools/call` is the non-cacheable example here: the spec types `CallToolResult` as a plain `Result`, - # while the results it types as `CacheableResult` are the discover, list, and read families. - # `ping` cannot stand in for it - SEP-2575 removed that method, so a modern request naming it is refused. - response = server.handle(modern_request(Methods::TOOLS_CALL, { name: "result_type_tool", arguments: {} })) - - refute response[:result].key?(:ttlMs) - refute response[:result].key?(:cacheScope) - end - - test "configured cache hints win over the modern defaults" do - server = Server.new(name: "cache_hints_test", tools: [result_type_tool], ttl_ms: 5000, cache_scope: "private") - - response = server.handle(modern_request(Methods::TOOLS_LIST, {})) - - assert_equal 5000, response.dig(:result, :ttlMs) - assert_equal "private", response.dig(:result, :cacheScope) - end - - test "modern resources/read results carry the default cache hints" do - server = Server.new(name: "cache_hints_test") - server.resources_read_handler do |params| - [{ uri: params[:uri], mimeType: "text/plain", text: "hi" }] - end - - response = server.handle(modern_request(Methods::RESOURCES_READ, { uri: "file:///x" })) - - assert_equal 0, response.dig(:result, :ttlMs) - assert_equal "private", response.dig(:result, :cacheScope) - end - - test "legacy cacheable results keep the opt-in cache hint emission" do - server = Server.new(name: "cache_hints_test", tools: [result_type_tool]) - - response = server.handle({ jsonrpc: "2.0", method: Methods::TOOLS_LIST, id: 1 }) - - refute response[:result].key?(:ttlMs) - refute response[:result].key?(:cacheScope) - end - - private - - # Builds a request carrying the SEP-2575 modern `_meta` envelope. - def modern_request(method, params, version: "2026-07-28", capabilities: {}) - { - jsonrpc: "2.0", - method: method, - id: 1, - params: params.merge( - _meta: { - "io.modelcontextprotocol/protocolVersion": version, - "io.modelcontextprotocol/clientInfo": { name: "modern_client", version: "2.0" }, - "io.modelcontextprotocol/clientCapabilities": capabilities, - }, - ), - } - end - - def result_type_tool - @result_type_tool ||= Tool.define(name: "result_type_tool") do |**| - Tool::Response.new([{ type: "text", text: "ok" }]) - end - end end end diff --git a/test/mcp/tool/input_schema_test.rb b/test/mcp/tool/input_schema_test.rb index 6b239eb..45f98a0 100644 --- a/test/mcp/tool/input_schema_test.rb +++ b/test/mcp/tool/input_schema_test.rb @@ -7,18 +7,13 @@ module MCP class InputSchemaTest < ActiveSupport::TestCase test "required arguments are converted to strings" do input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: [:message]) - assert_equal ["message"], input_schema.to_h[:required] + assert_equal ["message"], input_schema.schema[:required] end test "to_h returns a hash representation of the input schema" do input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"]) assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { message: { type: "string" } }, - required: ["message"], - }, + { type: "object", properties: { message: { type: "string" } }, required: ["message"] }, input_schema.to_h, ) end @@ -26,52 +21,11 @@ module MCP test "to_h returns a hash representation of the input schema with additionalProperties set to false" do input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"], additionalProperties: false) assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { message: { type: "string" } }, - required: ["message"], - additionalProperties: false, - }, + { type: "object", properties: { message: { type: "string" } }, required: ["message"], additionalProperties: false }, input_schema.to_h, ) end - test "to_h preserves user-supplied $schema dialect" do - input_schema = InputSchema.new( - "$schema": "https://json-schema.org/draft/2019-09/schema", - properties: { message: { type: "string" } }, - ) - assert_equal "https://json-schema.org/draft/2019-09/schema", input_schema.to_h[:"$schema"] - end - - test "validate_arguments works when user supplies a 2020-12 $schema" do - input_schema = InputSchema.new( - "$schema": "https://json-schema.org/draft/2020-12/schema", - properties: { foo: { type: "string" } }, - required: ["foo"], - ) - assert_nil(input_schema.validate_arguments(foo: "bar")) - assert_raises(InputSchema::ValidationError) do - input_schema.validate_arguments({ foo: 123 }) - end - end - - test "to_h preserves user-supplied $schema given via string key" do - # The initializer normalizes input through `JSON.parse(..., - # symbolize_names: true)`, so a string-keyed `"$schema"` should - # arrive at `schema_for_validation` the same as a symbol-keyed one. - input_schema = InputSchema.new( - { - "$schema" => "https://json-schema.org/draft/2020-12/schema", - "properties" => { "foo" => { "type" => "string" } }, - "required" => ["foo"], - }, - ) - assert_equal "https://json-schema.org/draft/2020-12/schema", input_schema.to_h[:"$schema"] - assert_nil(input_schema.validate_arguments(foo: "bar")) - end - test "missing_required_arguments returns an array of missing required arguments" do input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"]) assert_equal ["message"], input_schema.missing_required_arguments({}) @@ -79,20 +33,12 @@ module MCP test "missing_required_arguments returns an empty array if no required arguments are missing" do input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"]) - assert_equal([], input_schema.missing_required_arguments({ message: "Hello, world!" })) + assert_empty input_schema.missing_required_arguments({ message: "Hello, world!" }) end test "valid schema initialization" do schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"]) - assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { foo: { type: "string" } }, - required: ["foo"], - }, - schema.to_h, - ) + assert_equal({ type: "object", properties: { foo: { type: "string" } }, required: ["foo"] }, schema.to_h) end test "invalid schema raises argument error" do @@ -101,22 +47,6 @@ module MCP end end - test "rejects a draft-04-only boolean exclusiveMinimum under the 2020-12 dialect" do - # SEP-2106 validates tool schemas against the JSON Schema 2020-12 metaschema, - # where `exclusiveMinimum` must be a number. The draft-04 boolean form (deprecated since draft-06) - # is rejected at construction, matching the Python SDK's `jsonschema` validator selection. - error = assert_raises(ArgumentError) do - InputSchema.new(properties: { age: { type: "integer", minimum: 0, exclusiveMinimum: true } }) - end - assert_includes error.message, "Invalid JSON Schema" - end - - test "accepts the 2020-12 numeric exclusiveMinimum form" do - assert_nothing_raised do - InputSchema.new(properties: { age: { type: "integer", exclusiveMinimum: 0 } }) - end - end - test "schema without required arguments is valid" do assert_nothing_raised do InputSchema.new(properties: { foo: { type: "string" } }) @@ -155,68 +85,23 @@ module MCP test "unexpected errors bubble up from validate_arguments" do schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"]) - JSONSchemer::Schema.any_instance.stubs(:validate).raises("unexpected error") - - assert_raises(RuntimeError) do - schema.validate_arguments(foo: "bar") + JSON::Validator.stub(:fully_validate, ->(*) { raise "unexpected error" }) do + assert_raises(RuntimeError) do + schema.validate_arguments({ foo: "bar" }) + end end end - test "accepts schemas with $ref references" do - schema = InputSchema.new( - properties: { - foo: { type: "string" }, - }, - definitions: { - bar: { type: "string" }, - }, - required: ["foo"], - ) - assert_includes schema.to_h.keys, :definitions + test "rejects schemas with $ref references" do + assert_raises(ArgumentError) do + InputSchema.new(properties: { foo: { "$ref" => "#/definitions/bar" } }, required: ["foo"]) + end end - test "accepts schemas with $ref string key and includes $ref in to_h" do - schema = InputSchema.new({ - "properties" => { - "foo" => { "$ref" => "#/definitions/bar" }, - }, - "definitions" => { - "bar" => { "type" => "string" }, - }, - }) - assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref] - end - - test "accepts schemas with $ref symbol key and includes $ref in to_h" do - schema = InputSchema.new({ - properties: { - foo: { :$ref => "#/definitions/bar" }, - }, - definitions: { - bar: { type: "string" }, - }, - }) - assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref] - end - - test "keeps the object root type while accepting 2020-12 composition keywords" do - # Per SEP-2106, an input schema root must stay `type: "object"` but may use - # the full 2020-12 vocabulary below the root. - schema = InputSchema.new( - "$defs": { name: { type: "string", minLength: 1 } }, - properties: { - name: { "$ref": "#/$defs/name" }, - value: { oneOf: [{ type: "string" }, { type: "integer" }] }, - }, - if: { properties: { value: { type: "integer" } } }, - then: { required: ["name"] }, - allOf: [{ properties: { extra: { type: "boolean" } } }], - ) - - assert_equal "object", schema.to_h[:type] - assert schema.to_h.key?(:"$defs") - assert schema.to_h.key?(:if) - assert schema.to_h.key?(:allOf) + test "rejects schemas with symbol $ref references" do + assert_raises(ArgumentError) do + InputSchema.new(properties: { foo: { :$ref => "#/definitions/bar" } }, required: ["foo"]) + end end test "== compares two input schemas with the same properties, required fields" do @@ -236,26 +121,6 @@ module MCP schema6 = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"], additionalProperties: false) refute_equal schema1, schema6 end - - test "format keyword is not enforced (legacy behavior)" do - schema = InputSchema.new( - properties: { email: { type: "string", format: "email" } }, - required: ["email"], - ) - assert_nil(schema.validate_arguments(email: "not_an_email")) - end - - test "invalid pattern raises ArgumentError, not RegexpError" do - error = assert_raises(ArgumentError) do - InputSchema.new(properties: { id: { type: "string", pattern: "[" } }) - end - assert_includes error.message, "Invalid JSON Schema" - end - - test "Symbol values in arguments are treated as strings" do - schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"]) - assert_nil(schema.validate_arguments(foo: :bar)) - end end end end diff --git a/test/mcp/tool/output_schema_test.rb b/test/mcp/tool/output_schema_test.rb index a9522cc..0eb160d 100644 --- a/test/mcp/tool/output_schema_test.rb +++ b/test/mcp/tool/output_schema_test.rb @@ -8,38 +8,11 @@ module MCP test "to_h returns a hash representation of the output schema" do output_schema = OutputSchema.new(properties: { result: { type: "string" } }, required: ["result"]) assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, + { type: "object", properties: { result: { type: "string" } }, required: ["result"] }, output_schema.to_h, ) end - test "to_h preserves user-supplied $schema dialect" do - output_schema = OutputSchema.new( - "$schema": "https://json-schema.org/draft/2019-09/schema", - properties: { result: { type: "string" } }, - ) - assert_equal "https://json-schema.org/draft/2019-09/schema", output_schema.to_h[:"$schema"] - end - - test "validate_result works when user supplies a 2020-12 $schema" do - output_schema = OutputSchema.new( - "$schema": "https://json-schema.org/draft/2020-12/schema", - properties: { result: { type: "string" } }, - required: ["result"], - ) - assert_nothing_raised do - output_schema.validate_result({ result: "success" }) - end - assert_raises(OutputSchema::ValidationError) do - output_schema.validate_result({ result: 123 }) - end - end - test "validate_result validates result against the schema" do output_schema = OutputSchema.new(properties: { result: { type: "string" } }, required: ["result"]) assert_nothing_raised do @@ -84,15 +57,7 @@ module MCP test "valid schema initialization" do schema = OutputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"]) - assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { foo: { type: "string" } }, - required: ["foo"], - }, - schema.to_h, - ) + assert_equal({ type: "object", properties: { foo: { type: "string" } }, required: ["foo"] }, schema.to_h) end test "invalid schema raises argument error" do @@ -110,48 +75,23 @@ module MCP test "unexpected errors bubble up from validate_result" do schema = OutputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"]) - JSONSchemer::Schema.any_instance.stubs(:validate).raises("unexpected error") - - assert_raises(RuntimeError) do - schema.validate_result(foo: "bar") + JSON::Validator.stub(:fully_validate, ->(*) { raise "unexpected error" }) do + assert_raises(RuntimeError) do + schema.validate_result({ foo: "bar" }) + end end end - test "accepts schemas with $ref references" do - schema = OutputSchema.new( - properties: { - foo: { type: "string" }, - }, - definitions: { - bar: { type: "string" }, - }, - required: ["foo"], - ) - assert_includes schema.to_h.keys, :definitions + test "rejects schemas with $ref references" do + assert_raises(ArgumentError) do + OutputSchema.new(properties: { foo: { "$ref" => "#/definitions/bar" } }, required: ["foo"]) + end end - test "accepts schemas with $ref string key and includes $ref in to_h" do - schema = OutputSchema.new({ - "properties" => { - "foo" => { "$ref" => "#/definitions/bar" }, - }, - "definitions" => { - "bar" => { "type" => "string" }, - }, - }) - assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref] - end - - test "accepts schemas with $ref symbol key and includes $ref in to_h" do - schema = OutputSchema.new({ - properties: { - foo: { :$ref => "#/definitions/bar" }, - }, - definitions: { - bar: { type: "string" }, - }, - }) - assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref] + test "rejects schemas with symbol $ref references" do + assert_raises(ArgumentError) do + OutputSchema.new(properties: { foo: { :$ref => "#/definitions/bar" } }, required: ["foo"]) + end end test "== compares two output schemas with the same properties and required fields" do @@ -171,10 +111,7 @@ module MCP test "empty schema is valid" do schema = OutputSchema.new - assert_equal( - { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" }, - schema.to_h, - ) + assert_equal({ type: "object" }, schema.to_h) end test "validates complex nested schemas" do @@ -215,51 +152,6 @@ module MCP end end - test "does not inject a root type into a root-level oneOf schema" do - # Per SEP-2106, an output schema may be any JSON Schema 2020-12 document. - # Merging `type: "object"` into a root combinator would produce a wrong schema. - schema = OutputSchema.new(oneOf: [{ type: "string" }, { type: "integer" }]) - - refute schema.to_h.key?(:type) - assert_equal [{ type: "string" }, { type: "integer" }], schema.to_h[:oneOf] - assert_nothing_raised { schema.validate_result("text") } - assert_nothing_raised { schema.validate_result(42) } - assert_raises(OutputSchema::ValidationError) { schema.validate_result(1.5) } - end - - test "does not inject a root type into a root-level $ref schema" do - schema = OutputSchema.new( - "$ref": "#/$defs/result", - "$defs": { result: { type: "string" } }, - ) - - refute schema.to_h.key?(:type) - assert_nothing_raised { schema.validate_result("text") } - assert_raises(OutputSchema::ValidationError) { schema.validate_result(42) } - end - - test "allows primitive root schemas" do - schema = OutputSchema.new(type: "string") - - assert_nothing_raised { schema.validate_result("text") } - assert_raises(OutputSchema::ValidationError) { schema.validate_result(42) } - end - - test "does not inject a root type into a root-level enum schema" do - schema = OutputSchema.new(enum: ["red", "green", "blue"]) - - refute schema.to_h.key?(:type) - assert_nothing_raised { schema.validate_result("red") } - assert_raises(OutputSchema::ValidationError) { schema.validate_result("yellow") } - end - - test "defaults a properties-only schema to a root object" do - # Wire-format regression: the common shorthand keeps serializing with the injected `type: "object"`. - schema = OutputSchema.new(properties: { result: { type: "string" } }) - - assert_equal "object", schema.to_h[:type] - end - test "allow to declare array schemas" do schema = OutputSchema.new({ type: "array", @@ -270,7 +162,6 @@ module MCP }) assert_equal( { - "$schema": "https://json-schema.org/draft/2020-12/schema", type: "array", items: { properties: { foo: { type: "string" } }, diff --git a/test/mcp/tool/response_test.rb b/test/mcp/tool/response_test.rb index afa7d3b..5fd70a8 100644 --- a/test/mcp/tool/response_test.rb +++ b/test/mcp/tool/response_test.rb @@ -16,12 +16,6 @@ module MCP refute response.error? end - test "#content_provided? distinguishes empty content from omitted or nil content" do - assert Response.new([]).content_provided? - refute Response.new.content_provided? - refute Response.new(nil).content_provided? - end - test "#initialize with content and error set to true" do content = [{ type: "text", @@ -113,7 +107,7 @@ module MCP actual = response.to_h assert_equal [:content, :isError, :structuredContent], actual.keys - assert_equal([], actual[:content]) + assert_empty actual[:content] assert_equal structured_content, actual[:structuredContent] refute actual[:isError] end @@ -124,24 +118,10 @@ module MCP actual = response.to_h assert_equal [:content, :isError, :structuredContent], actual.keys - assert_equal([], actual[:content]) + assert_empty actual[:content] assert_equal structured_content, actual[:structuredContent] refute actual[:isError] end - - test "#to_h includes _meta when present" do - meta = { "application/vnd.ant.mcp-app" => { "csp" => "default-src 'self'" } } - response = Response.new([{ type: "text", text: "ok" }], meta: meta) - actual = response.to_h - - assert_equal meta, actual[:_meta] - end - - test "#to_h omits _meta when nil" do - response = Response.new([{ type: "text", text: "ok" }]) - - refute response.to_h.key?(:_meta) - end end end end diff --git a/test/mcp/tool/schema_test.rb b/test/mcp/tool/schema_test.rb deleted file mode 100644 index cb3fd7a..0000000 --- a/test/mcp/tool/schema_test.rb +++ /dev/null @@ -1,129 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class Tool - class SchemaTest < ActiveSupport::TestCase - setup do - Schema::VALIDATION_CACHE.clear - end - - test "validates a schema once and reuses the result for identical schemas" do - JSONSchemer::Schema.any_instance.expects(:validate_schema).once.returns([]) - - schema = { properties: { validates_once: { type: "string" } } } - InputSchema.new(schema) - InputSchema.new(schema) - end - - test "validates distinct schemas separately" do - JSONSchemer::Schema.any_instance.expects(:validate_schema).twice.returns([]) - - InputSchema.new(properties: { distinct_a: { type: "string" } }) - InputSchema.new(properties: { distinct_b: { type: "string" } }) - end - - test "a cache hit still yields a usable, validated schema" do - schema = { properties: { cache_hit: { type: "string" } }, required: ["cache_hit"] } - InputSchema.new(schema) - cached = InputSchema.new(schema) - - assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { cache_hit: { type: "string" } }, - required: ["cache_hit"], - }, - cached.to_h, - ) - assert_nil(cached.validate_arguments(cache_hit: "value")) - assert_raises(InputSchema::ValidationError) do - cached.validate_arguments(cache_hit: 123) - end - end - - test "an invalid schema raises every time and is not cached" do - invalid = { properties: { not_cached: { type: "invalid_type" } } } - - assert_raises(ArgumentError) { InputSchema.new(invalid) } - assert_raises(ArgumentError) { InputSchema.new(invalid) } - end - - test "a schema nested deeper than MAX_SCHEMA_DEPTH raises" do - # SEP-2106 resource bounds: unbounded nesting would make downstream validation arbitrarily expensive. - # Each wrapping adds two levels (the schema hash and its `properties` hash), so this is the smallest - # nesting that exceeds MAX_SCHEMA_DEPTH. - wrappings = Schema::MAX_SCHEMA_DEPTH / 2 + 1 - schema = { type: "string" } - wrappings.times do - schema = { type: "object", properties: { child: schema } } - end - - error = assert_raises(ArgumentError) { InputSchema.new(schema) } - assert_match(/maximum depth/, error.message) - end - - test "a schema with more subschema objects than MAX_SUBSCHEMA_COUNT raises" do - properties = {} - (Schema::MAX_SUBSCHEMA_COUNT + 1).times do |i| - properties[:"property_#{i}"] = { type: "string" } - end - - error = assert_raises(ArgumentError) { InputSchema.new(properties: properties) } - assert_match(/subschema/, error.message) - end - - test "rejects a $ref pointing outside the schema document" do - # SEP-2106 requires same-document `$ref` resolution only; a remote URI or a sibling file must never trigger network - # or file access. - error = assert_raises(ArgumentError) do - InputSchema.new(properties: { foo: { "$ref": "https://example.com/schema.json#/defs/bar" } }) - end - assert_match(/same-document/, error.message) - - assert_raises(ArgumentError) do - InputSchema.new(properties: { foo: { "$ref": "other.json#/defs/bar" } }) - end - end - - test "rejects a $dynamicRef pointing outside the schema document" do - # 2020-12 allows `$dynamicRef` to carry an absolute URI too, so the same-document restriction must cover it as well as `$ref`. - error = assert_raises(ArgumentError) do - InputSchema.new(properties: { foo: { "$dynamicRef": "https://example.com/schema.json#meta" } }) - end - assert_match(/same-document/, error.message) - assert_match(/\$dynamicRef/, error.message) - end - - test "accepts a same-document $ref" do - assert_nothing_raised do - InputSchema.new( - "$defs": { bar: { type: "string" } }, - properties: { foo: { "$ref": "#/$defs/bar" } }, - ) - end - end - - test "ValidationCache evicts the oldest entry beyond its max size" do - cache = Schema::ValidationCache.new(max_size: 2) - cache.store("a") - cache.store("b") - cache.store("c") - - refute cache.validated?("a") - assert cache.validated?("b") - assert cache.validated?("c") - end - - test "ValidationCache#clear empties the cache" do - cache = Schema::ValidationCache.new - cache.store("a") - cache.clear - - refute cache.validated?("a") - end - end - end -end diff --git a/test/mcp/tool_test.rb b/test/mcp/tool_test.rb index bdec7b6..ede3fbf 100644 --- a/test/mcp/tool_test.rb +++ b/test/mcp/tool_test.rb @@ -33,7 +33,7 @@ module MCP title: "Mock Tool", description: "a mock tool for testing", icons: [{ mimeType: "image/png", sizes: ["48x48", "96x96"], src: "https://example.com", theme: "light" }], - inputSchema: { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" }, + inputSchema: { type: "object" }, } tool = Tool.define( name: "mock_tool", @@ -109,15 +109,7 @@ module MCP tool = MockTool assert_equal "my_mock_tool", tool.name_value assert_equal "a mock tool for testing", tool.description - assert_equal( - { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { message: { type: "string" } }, - required: ["message"], - }, - tool.input_schema.to_h, - ) + assert_equal({ type: "object", properties: { message: { type: "string" } }, required: ["message"] }, tool.input_schema.to_h) end test "defaults to class name as tool name" do @@ -134,7 +126,7 @@ module MCP tool = NoInputSchemaTool - expected = { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" } + expected = { type: "object" } assert_equal expected, tool.input_schema.to_h end @@ -145,12 +137,7 @@ module MCP tool = InputSchemaTool - expected = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { message: { type: "string" } }, - required: ["message"], - } + expected = { type: "object", properties: { message: { type: "string" } }, required: ["message"] } assert_equal expected, tool.input_schema.to_h end @@ -167,8 +154,8 @@ module MCP end assert_includes error.message, "Invalid JSON Schema" - assert_includes error.message, "properties/count/minimum" - assert_includes error.message, "number" + assert_includes error.message, "#/properties/count/minimum" + assert_includes error.message, "string did not match the following type: number" end test ".define allows definition of simple tools with a block" do @@ -333,7 +320,7 @@ module MCP assert_equal [{ type: "text", content: "OK" }], response.content end - test "input_schema accepts $ref in schema" do + test "input_schema rejects any $ref in schema" do schema_with_ref = { properties: { foo: { "$ref" => "#/definitions/bar" }, @@ -343,10 +330,12 @@ module MCP bar: { type: "string" }, }, } - tool_class = Class.new(MCP::Tool) do - input_schema schema_with_ref + error = assert_raises(ArgumentError) do + Class.new(MCP::Tool) do + input_schema schema_with_ref + end end - assert_equal "#/definitions/bar", tool_class.input_schema.to_h[:properties][:foo][:$ref] + assert_match(/Invalid JSON Schema/, error.message) end test "#to_h includes outputSchema when present" do @@ -355,13 +344,8 @@ module MCP title: "Mock Tool", description: "a mock tool for testing", icons: [{ mimeType: "image/png", sizes: ["48x48", "96x96"], src: "https://example.com", theme: "light" }], - inputSchema: { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" }, - outputSchema: { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - }, + inputSchema: { type: "object" }, + outputSchema: { type: "object", properties: { result: { type: "string" } }, required: ["result"] }, } tool = Tool.define( name: "mock_tool", @@ -394,12 +378,7 @@ module MCP end tool = HashOutputSchemaTool - expected = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - } + expected = { type: "object", properties: { result: { type: "string" } }, required: ["result"] } assert_equal expected, tool.output_schema.to_h end @@ -409,12 +388,7 @@ module MCP end tool = OutputSchemaObjectTool - expected = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - } + expected = { type: "object", properties: { result: { type: "string" } }, required: ["result"] } assert_equal expected, tool.output_schema.to_h end @@ -431,11 +405,11 @@ module MCP end assert_includes error.message, "Invalid JSON Schema" - assert_includes error.message, "properties/count/minimum" - assert_includes error.message, "number" + assert_includes error.message, "#/properties/count/minimum" + assert_includes error.message, "string did not match the following type: number" end - test "output_schema accepts $ref in schema" do + test "output_schema rejects any $ref in schema" do schema_with_ref = { properties: { foo: { "$ref" => "#/definitions/bar" }, @@ -445,10 +419,12 @@ module MCP bar: { type: "string" }, }, } - tool_class = Class.new(MCP::Tool) do - output_schema schema_with_ref + error = assert_raises(ArgumentError) do + Class.new(MCP::Tool) do + output_schema schema_with_ref + end end - assert_equal "#/definitions/bar", tool_class.output_schema.to_h[:properties][:foo][:$ref] + assert_match(/Invalid JSON Schema/, error.message) end test ".define allows definition of tools with output_schema" do @@ -464,12 +440,7 @@ module MCP assert_equal "mock_tool", tool.name_value assert_equal "a mock tool for testing", tool.description assert_instance_of Tool::OutputSchema, tool.output_schema - expected_output_schema = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" } }, - required: ["result"], - } + expected_output_schema = { type: "object", properties: { result: { type: "string" } }, required: ["result"] } assert_equal expected_output_schema, tool.output_schema.to_h end @@ -491,20 +462,10 @@ module MCP assert_equal "test_tool_with_output", tool.name_value assert_equal "a test tool with output schema", tool.description - expected_input = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { message: { type: "string" } }, - required: ["message"], - } + expected_input = { type: "object", properties: { message: { type: "string" } }, required: ["message"] } assert_equal expected_input, tool.input_schema.to_h - expected_output = { - "$schema": "https://json-schema.org/draft/2020-12/schema", - type: "object", - properties: { result: { type: "string" }, success: { type: "boolean" } }, - required: ["result", "success"], - } + expected_output = { type: "object", properties: { result: { type: "string" }, success: { type: "boolean" } }, required: ["result", "success"] } assert_equal expected_output, tool.output_schema.to_h end diff --git a/test/mcp/trace_context_test.rb b/test/mcp/trace_context_test.rb deleted file mode 100644 index cfe59d8..0000000 --- a/test/mcp/trace_context_test.rb +++ /dev/null @@ -1,20 +0,0 @@ -# frozen_string_literal: true - -require "test_helper" - -module MCP - class TraceContextTest < ActiveSupport::TestCase - test "exposes the W3C Trace Context reserved _meta key names" do - # The exact un-prefixed names are reserved by SEP-414; renaming any of them - # would break interoperability with other SDKs. - assert_equal "traceparent", TraceContext::TRACEPARENT_META_KEY - assert_equal "tracestate", TraceContext::TRACESTATE_META_KEY - assert_equal "baggage", TraceContext::BAGGAGE_META_KEY - end - - test "META_KEYS lists all reserved keys and is frozen" do - assert_equal ["traceparent", "tracestate", "baggage"], TraceContext::META_KEYS - assert_predicate TraceContext::META_KEYS, :frozen? - end - end -end diff --git a/test/test_helper.rb b/test/test_helper.rb index 8cd6b9e..19e9974 100644 --- a/test/test_helper.rb +++ b/test/test_helper.rb @@ -6,38 +6,9 @@ require "minitest/autorun" require "minitest/mock" require "mocha/minitest" -# mocha relies on `Hash.ruby2_keywords_hash?`, which is absent on Ruby 2.7.0 and the earlier 2.7.x releases -# before it was backported. Those versions also lack the flag-setting APIs, so no hash is ever flagged as -# ruby2_keywords and returning `false` is correct. Without this shim, mocha raises `NoMethodError` and -# the suite cannot run on Ruby 2.7.0. -unless Hash.respond_to?(:ruby2_keywords_hash?) - def Hash.ruby2_keywords_hash?(_hash) - false - end -end - require "active_support" require "active_support/test_case" require "sorbet-runtime" if RUBY_VERSION >= "3.0" require_relative "instrumentation_test_helper" -require_relative "initialize_params_test_helper" - -module DeprecationWarningTestHelper - def assert_deprecation_warning(message_pattern, &block) - original_verbose = $VERBOSE - $VERBOSE = false - assert_output(nil, message_pattern, &block) - ensure - $VERBOSE = original_verbose - end - - def assert_no_deprecation_warning(&block) - original_verbose = $VERBOSE - $VERBOSE = false - assert_output(nil, "", &block) - ensure - $VERBOSE = original_verbose - end -end