Finalize server/discover and Add Client Modern Lifecycle Support per SEP-2575
## Motivation and Context Final step of the stateless lifecycle (SEP-2575, modelcontextprotocol/modelcontextprotocol#2575) for the 2026-07-28 MCP spec release, now that the server core and both server transports can serve modern traffic. Server side, `Server#discover` reaches its spec-final shape: - `supportedVersions` advertises modern versions only, matching the TypeScript and Python SDKs: legacy versions are negotiated via `initialize`, not selected from discovery. This also closes an interop hazard of the interim response: auto-negotiating TS and Python clients treat any `DiscoverResult` as proof of a modern server and do not fall back to `initialize`, so advertising only legacy versions made them fail outright. - The `ttlMs`/`cacheScope` cache hints are REQUIRED on `DiscoverResult` (unlike the opt-in SEP-2549 hints on list and read results), so the spec defaults (`0`, `"private"`) fill in when the server was not configured with `ttl_ms`/`cache_scope`, and the configured SEP-2549 values are reused otherwise. - The server identity rides in the result `_meta` as the optional `io.modelcontextprotocol/serverInfo` stamp instead of a top-level `serverInfo` field, following spec PR modelcontextprotocol/modelcontextprotocol#3002 (the TypeScript SDK stamps `_meta` the same way and the Python `DiscoverResult` carries no top-level `serverInfo`, so the top-level placement was invisible to both). `Client#discover` and the `server_implementation` reader read the `_meta` stamp with a top-level fallback for servers built against the frozen SEP text, and the key is exposed as `RequestEnvelope::SERVER_INFO_META_KEY`. Client side, both bundled transports learn the modern lifecycle, and `MCP::Client` negotiates it automatically by default: - `MCP::Client#discover` sends `server/discover` and returns a `DiscoverResult` struct (`supported_versions`, `capabilities`, `server_info`, `instructions`, `ttl_ms`, `cache_scope`). It works before `connect`; the stdio transport's connect guard exempts `server/discover` and spawns the subprocess on demand. - `connect` gains `mode:` and defaults to automatic negotiation, joining the Python, Go, and C# SDKs (the TypeScript SDK keeps a legacy default): transports whose `connect` declares `mode:` (the bundled HTTP and stdio transports) receive `:auto`, which probes `server/discover` and falls back to the legacy handshake on any discovery failure, including a successful discovery without a mutually supported modern version (rollout tolerance for servers that answer discovery while only serving legacy versions). Custom transports whose `connect` does not declare `mode:` keep receiving the historical legacy call shape, detected by keyword introspection; a bare `**kwargs` deliberately does not count, so wrappers and test doubles that absorb arbitrary keywords stay on the legacy shape. An explicit `:modern`/`:auto` against such a transport raises `ArgumentError` instead of silently downgrading. - The mode vocabulary is `:legacy`/`:auto` (shared with the Python and TypeScript SDKs) plus an explicit `:modern`, instead of folding a version-string pin into `mode` as Python and TypeScript do: this client has carried the scalar `protocol_version:` keyword since the handshake landed, so a second version-bearing input would make the API ambiguous about which one wins. `mode:` stays the strategy and `protocol_version:` stays the version, the same orthogonal split as the Go and C# scalar version pins; Python's `mode="2026-07-28"` is expressed here as `mode: :modern` with `protocol_version: "2026-07-28"`. - An explicit legacy-generation `protocol_version` (e.g. `"2025-11-25"`) pins the legacy handshake without a probe, so an explicitly requested version is never overridden by the default negotiation adopting the modern lifecycle. `mode: :legacy` forces the classic handshake unconditionally; prefer it for spawn-per-invocation CLI tools and when using server-initiated requests, which exist only on the legacy lifecycle. - Because the raw `connect` return value and `server_info` mirror the wire result, their shape depends on the negotiated era (`InitializeResult` vs `DiscoverResult`). New era-independent readers absorb that difference: `MCP::Client#protocol_version` (negotiated or adopted version; backed by a new stdio transport reader and the existing HTTP one), `#server_capabilities`, `#instructions`, and `#server_implementation`, which reads the spec-final `_meta` `io.modelcontextprotocol/serverInfo` stamp with a top-level fallback and returns `nil` when a modern server does not identify itself. `server_info` remains the permanent raw window to everything the readers do not cover. - The stdio `server/discover` probe is bounded by a new `DEFAULT_DISCOVER_PROBE_TIMEOUT` (5 seconds, matching the C# SDK) 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 must read as legacy evidence for the auto fallback instead of blocking `connect` forever. Regular requests keep the unbounded default. - In modern mode, the new shared `MCP::Client::ModernEnvelope` stamps the SEP-2575 `_meta` triple onto every request (never onto notifications, whose `_meta` carries no envelope), reusing the reserved key names from `MCP::RequestEnvelope`. The HTTP transport sends the matching `MCP-Protocol-Version` header and keeps the existing `Mcp-Method`/`Mcp-Name` mirror headers; no `Mcp-Session-Id` is ever attached because `initialize` is never sent. - The conformance client pins `mode: :legacy`: the referee validates the legacy `initialize` handshake and its scenario servers do not expect a preceding probe. Resolves #389. ## How Has This Been Tested? New tests in `test/mcp/server_test.rb` pin the required cache hints (spec defaults and configured SEP-2549 values); the existing discover assertions across `server_test.rb` and both transport test files were updated to the modern-only `supportedVersions`. New tests in `test/mcp/client_test.rb` cover the `DiscoverResult` struct mapping, `ValidationError`/`ServerError` on malformed and error responses, and the mode resolution contract: the `:auto` default on transports declaring `mode:`, the unchanged legacy call shape for transports without it, the legacy pin for an explicit stable `protocol_version`, `ArgumentError` for explicit non-legacy modes on transports without `mode:`, unknown-mode rejection, and the era-independent readers against legacy results, modern results, the `_meta` `serverInfo` stamp, and absence. New tests in `test/mcp/client/http_test.rb` cover modern adoption via discovery, envelope stamping with the matching header on subsequent requests, the no-mutual-version failure, both auto-mode fallbacks, and argument validation. New tests in `test/mcp/client/stdio_test.rb` cover pre-connect `server/discover`, modern adoption with envelope stamping and no `initialize` frame, the auto-mode fallback, the probe timeout default applying only while probing, and the fallback when a server never answers the probe. ## Breaking Changes `server/discover` responses change shape (modern-only `supportedVersions` plus the required `ttlMs`/`cacheScope`); this method has not shipped in a gem release yet, so no released behavior changes. On the bundled HTTP and stdio transports, `MCP::Client#connect` without `mode:` now probes `server/discover` before the legacy handshake: against legacy servers this adds one round trip and an unknown-method entry in their logs with an unchanged final result, and once a server serves the modern lifecycle the connection adopts it, changing the raw result shape from `InitializeResult` to `DiscoverResult`. Pass `mode: :legacy` or an explicit legacy-generation `protocol_version` to keep the previous behavior unconditionally, or use the era-independent readers, which are stable across both lifecycles. Custom transports without `mode:` and direct `transport.connect` calls are unaffected.
This commit is contained in:
Koichi ITO
parent
d51d4a0f91
commit
d0d7308a89
6 changed files with 1203 additions and 151 deletions
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@ -1844,6 +1844,109 @@ module MCP
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refute_predicate(client, :connected?)
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end
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def test_connect_modern_probes_discover_and_adopts_the_modern_lifecycle
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discover_stub = stub_discover
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result = client.connect(mode: :modern)
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assert_requested(discover_stub)
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assert_predicate(client, :connected?)
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assert_predicate(client, :modern?)
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assert_equal(["2026-07-28"], result["supportedVersions"])
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assert_equal(result, client.server_info)
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assert_equal("2026-07-28", client.protocol_version)
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end
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def test_modern_requests_carry_the_envelope_and_matching_header
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stub_discover
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client.connect(
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mode: :modern,
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client_info: { name: "my-app", version: "9.9" },
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capabilities: { elicitation: {} },
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)
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request_stub = stub_request(:post, url).with do |req|
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body = JSON.parse(req.body)
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meta = body.dig("params", "_meta")
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body["method"] == "tools/list" &&
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req.headers["Mcp-Protocol-Version"] == "2026-07-28" &&
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meta == {
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"io.modelcontextprotocol/protocolVersion" => "2026-07-28",
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"io.modelcontextprotocol/clientInfo" => { "name" => "my-app", "version" => "9.9" },
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"io.modelcontextprotocol/clientCapabilities" => { "elicitation" => {} },
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}
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end.to_return(
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status: 200,
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headers: { "Content-Type" => "application/json" },
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body: { result: { tools: [] } }.to_json,
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)
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client.send_request(request: { jsonrpc: "2.0", id: "1", method: "tools/list" })
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assert_requested(request_stub)
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end
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def test_connect_modern_fails_without_a_mutual_modern_version
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stub_request(:post, url).with do |req|
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JSON.parse(req.body)["method"] == "server/discover"
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end.to_return(
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status: 200,
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headers: { "Content-Type" => "application/json" },
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body: { result: { supportedVersions: ["2025-11-25"] } }.to_json,
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)
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error = assert_raises(RequestHandlerError) { client.connect(mode: :modern) }
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assert_includes(error.message, "no mutually supported modern protocol version")
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refute_predicate(client, :connected?)
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refute_predicate(client, :modern?)
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end
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def test_connect_auto_falls_back_to_the_legacy_handshake_on_discovery_errors
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stub_request(:post, url).with do |req|
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JSON.parse(req.body)["method"] == "server/discover"
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end.to_return(
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status: 200,
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headers: { "Content-Type" => "application/json" },
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body: { error: { code: -32601, message: "Method not found" } }.to_json,
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)
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init_stub = stub_initialize
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notification_stub = stub_notification
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result = client.connect(mode: :auto)
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assert_requested(init_stub)
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assert_requested(notification_stub)
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refute_predicate(client, :modern?)
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assert_predicate(client, :connected?)
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assert_equal("2025-11-25", result["protocolVersion"])
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end
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def test_connect_auto_falls_back_when_discovery_lacks_a_mutual_modern_version
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# Rollout tolerance: a server may answer discovery while only serving legacy versions;
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# auto mode falls back to the legacy handshake.
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stub_request(:post, url).with do |req|
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JSON.parse(req.body)["method"] == "server/discover"
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end.to_return(
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status: 200,
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headers: { "Content-Type" => "application/json" },
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body: { result: { supportedVersions: ["2025-11-25"] } }.to_json,
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)
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init_stub = stub_initialize
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stub_notification
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client.connect(mode: :auto)
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assert_requested(init_stub)
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refute_predicate(client, :modern?)
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assert_predicate(client, :connected?)
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end
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def test_connect_rejects_unknown_modes_and_legacy_versions_for_modern_mode
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assert_raises(ArgumentError) { client.connect(mode: :bogus) }
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assert_raises(ArgumentError) { client.connect(mode: :modern, protocol_version: "2025-11-25") }
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end
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def test_reconnect_after_close
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stub_initialize
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stub_notification
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@ -1949,6 +2052,24 @@ module MCP
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.to_return(status: 202, body: "")
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end
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def stub_discover
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stub_request(:post, url).with do |req|
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JSON.parse(req.body)["method"] == "server/discover"
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end.to_return(
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status: 200,
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headers: { "Content-Type" => "application/json" },
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body: {
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result: {
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supportedVersions: ["2026-07-28"],
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capabilities: { tools: {} },
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_meta: { "io.modelcontextprotocol/serverInfo": { name: "test-server", version: "1.0" } },
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ttlMs: 0,
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cacheScope: "private",
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},
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}.to_json,
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)
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end
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def stub_request(method, url)
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WebMock.stub_request(method, url)
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end
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@ -1414,6 +1414,198 @@ module MCP
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[transport, server_thread, [stdin_read, stdin_write, stdout_read, stdout_write]]
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end
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def test_send_request_allows_server_discover_before_connect
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stdin_read, stdin_write = IO.pipe
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stdout_read, stdout_write = IO.pipe
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stderr_read, _ = IO.pipe
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Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread])
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transport = Stdio.new(command: "ruby", args: ["server.rb"])
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server_thread = Thread.new do
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discover_request = JSON.parse(stdin_read.gets)
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response = {
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jsonrpc: "2.0",
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id: discover_request["id"],
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result: { supportedVersions: ["2026-07-28"], ttlMs: 0, cacheScope: "private" },
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}
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stdout_write.puts(JSON.generate(response))
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stdout_write.flush
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end
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# No prior `connect`: `server/discover` (SEP-2575) is sessionless discovery.
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response = transport.send_request(request: { jsonrpc: "2.0", id: "d1", method: "server/discover" })
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assert_equal(["2026-07-28"], response.dig("result", "supportedVersions"))
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refute_predicate(transport, :connected?)
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ensure
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server_thread&.join
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[stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io|
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io.close unless io.closed?
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end
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end
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def test_connect_modern_probes_discover_and_stamps_requests
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stdin_read, stdin_write = IO.pipe
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stdout_read, stdout_write = IO.pipe
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stderr_read, _ = IO.pipe
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Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread])
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transport = Stdio.new(command: "ruby", args: ["server.rb"])
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received = []
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server_thread = Thread.new do
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discover_request = JSON.parse(stdin_read.gets)
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received << discover_request
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stdout_write.puts(JSON.generate({
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jsonrpc: "2.0",
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id: discover_request["id"],
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result: {
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supportedVersions: ["2026-07-28"],
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capabilities: {},
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serverInfo: { name: "test-server", version: "1.0" },
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ttlMs: 0,
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cacheScope: "private",
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},
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}))
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stdout_write.flush
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tools_request = JSON.parse(stdin_read.gets)
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received << tools_request
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stdout_write.puts(JSON.generate({ jsonrpc: "2.0", id: tools_request["id"], result: { tools: [] } }))
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stdout_write.flush
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end
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result = transport.connect(mode: :modern, client_info: { name: "my-app", version: "9.9" })
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response = transport.send_request(request: { jsonrpc: "2.0", id: "t1", method: "tools/list" })
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assert_equal(["2026-07-28"], result["supportedVersions"])
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assert_predicate(transport, :modern?)
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assert_predicate(transport, :connected?)
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assert_equal("2026-07-28", transport.protocol_version)
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assert_equal("t1", response["id"])
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# No `initialize` was sent; both frames carry the SEP-2575 envelope.
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assert_equal(["server/discover", "tools/list"], received.map { |frame| frame["method"] })
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triple = received[1].dig("params", "_meta")
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assert_equal("2026-07-28", triple["io.modelcontextprotocol/protocolVersion"])
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assert_equal({ "name" => "my-app", "version" => "9.9" }, triple["io.modelcontextprotocol/clientInfo"])
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assert_equal({}, triple["io.modelcontextprotocol/clientCapabilities"])
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ensure
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server_thread&.join
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[stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io|
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io.close unless io.closed?
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end
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end
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def test_connect_auto_falls_back_to_the_legacy_handshake
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stdin_read, stdin_write = IO.pipe
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stdout_read, stdout_write = IO.pipe
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stderr_read, _ = IO.pipe
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Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread])
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transport = Stdio.new(command: "ruby", args: ["server.rb"])
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server_thread = Thread.new do
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discover_request = JSON.parse(stdin_read.gets)
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stdout_write.puts(JSON.generate({
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jsonrpc: "2.0",
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id: discover_request["id"],
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error: { code: -32601, message: "Method not found" },
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}))
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stdout_write.flush
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init_request = JSON.parse(stdin_read.gets)
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stdout_write.puts(JSON.generate({
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jsonrpc: "2.0",
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id: init_request["id"],
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result: {
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protocolVersion: "2025-11-25",
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capabilities: {},
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serverInfo: { name: "test-server", version: "1.0" },
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},
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}))
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stdout_write.flush
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# `notifications/initialized`
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stdin_read.gets
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end
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result = transport.connect(mode: :auto)
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assert_equal("2025-11-25", result["protocolVersion"])
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assert_equal("2025-11-25", transport.protocol_version)
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refute_predicate(transport, :modern?)
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assert_predicate(transport, :connected?)
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ensure
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server_thread&.join
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[stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io|
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io.close unless io.closed?
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end
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end
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def test_connect_auto_bounds_the_discover_probe_when_no_read_timeout_is_configured
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transport = Stdio.new(command: "ruby", args: ["server.rb"])
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transport.stubs(:start)
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observed_timeout = nil
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transport.define_singleton_method(:probe_discover) do
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observed_timeout = @read_timeout
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raise RequestHandlerError.new("probe timed out", {}, error_type: :internal_error)
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end
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transport.define_singleton_method(:connect_legacy) do |**|
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{ "protocolVersion" => "2025-11-25" }
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end
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result = transport.connect(mode: :auto)
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assert_equal(Stdio::DEFAULT_DISCOVER_PROBE_TIMEOUT, observed_timeout)
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assert_nil(transport.instance_variable_get(:@read_timeout))
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assert_equal("2025-11-25", result["protocolVersion"])
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end
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def test_connect_auto_falls_back_when_the_server_never_answers_the_probe
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stdin_read, stdin_write = IO.pipe
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stdout_read, stdout_write = IO.pipe
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stderr_read, _ = IO.pipe
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Open3.stubs(:popen3).returns([stdin_write, stdout_read, stderr_read, mock_wait_thread])
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# A configured `read_timeout` also bounds the probe; the server below reads
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# the `server/discover` request and never responds, which must count as
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# legacy evidence instead of blocking `connect` forever.
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transport = Stdio.new(command: "ruby", args: ["server.rb"], read_timeout: 0.05)
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server_thread = Thread.new do
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# Silently swallow the probe.
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stdin_read.gets
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init_request = JSON.parse(stdin_read.gets)
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stdout_write.puts(JSON.generate({
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jsonrpc: "2.0",
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id: init_request["id"],
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result: {
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protocolVersion: "2025-11-25",
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capabilities: {},
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serverInfo: { name: "test-server", version: "1.0" },
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},
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}))
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stdout_write.flush
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# `notifications/initialized`
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stdin_read.gets
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end
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result = transport.connect(mode: :auto)
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assert_equal("2025-11-25", result["protocolVersion"])
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refute_predicate(transport, :modern?)
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ensure
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server_thread&.join
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[stdin_read, stdin_write, stdout_read, stdout_write, stderr_read].each do |io|
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io.close unless io.closed?
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end
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end
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def mock_wait_thread
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thread = mock("wait_thread")
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thread.stubs(:alive?).returns(true)
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|
|
@ -85,6 +85,218 @@ module MCP
|
|||
assert_includes(error.message, "does not support server-to-client requests")
|
||||
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)
|
||||
|
|
|
|||
|
|
@ -583,7 +583,7 @@ module MCP
|
|||
modern_ping_request(id: 3),
|
||||
])
|
||||
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, responses[0].dig(:result, :supportedVersions)
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, responses[0].dig(:result, :supportedVersions)
|
||||
assert_equal :modern, session_era
|
||||
assert_equal ErrorCodes::UNSUPPORTED_PROTOCOL_VERSION, responses[1].dig(:error, :code)
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, responses[1].dig(:error, :data, :supported)
|
||||
|
|
|
|||
|
|
@ -660,7 +660,7 @@ module MCP
|
|||
|
||||
assert_equal 200, response[0]
|
||||
body = JSON.parse(response[2][0])
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
refute response[1].key?("mcp-session-id")
|
||||
end
|
||||
|
||||
|
|
@ -678,7 +678,7 @@ module MCP
|
|||
|
||||
assert_equal 200, response[0]
|
||||
body = JSON.parse(response[2][0])
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
end
|
||||
|
||||
test "rejects duplicate SSE connection with 409" do
|
||||
|
|
@ -5426,7 +5426,7 @@ module MCP
|
|||
assert_equal 200, response[0]
|
||||
refute response[1].key?("mcp-session-id")
|
||||
body = JSON.parse(response[2][0])
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, body.dig("result", "supportedVersions")
|
||||
end
|
||||
|
||||
test "legacy POST rejects a modern envelope body without the modern header as -32020" do
|
||||
|
|
|
|||
|
|
@ -129,10 +129,13 @@ module MCP
|
|||
response = @server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })
|
||||
result = response[:result]
|
||||
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, result[:supportedVersions]
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, result[:supportedVersions]
|
||||
assert_equal @server.capabilities, result[:capabilities]
|
||||
assert_equal @server_name, result.dig(:serverInfo, :name)
|
||||
assert_equal "1.2.3", result.dig(:serverInfo, :version)
|
||||
# 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
|
||||
|
||||
|
|
@ -142,7 +145,7 @@ module MCP
|
|||
|
||||
response = server.handle({ jsonrpc: "2.0", method: "server/discover", id: 1 })
|
||||
|
||||
assert_equal Configuration::SUPPORTED_STABLE_PROTOCOL_VERSIONS, response.dig(:result, :supportedVersions)
|
||||
assert_equal Configuration::SUPPORTED_MODERN_PROTOCOL_VERSIONS, response.dig(:result, :supportedVersions)
|
||||
end
|
||||
|
||||
test "#handle server/discover does not mark the session initialized" do
|
||||
|
|
@ -167,6 +170,26 @@ module MCP
|
|||
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") { {} }
|
||||
|
|
|
|||
Loading…
Reference in a new issue