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Filename Latest commit message Latest commit date
Anar Azadaliyev 65d2b29da5
 fix(server): remove initialized notification gate to support Streamable HTTP (#788) 
* fix(server): remove initialized notification gate to support Streamable HTTP

The server's init handshake loop fatally rejected any request arriving
before the `notifications/initialized` message. This breaks Streamable
HTTP clients where each JSON-RPC message is a separate POST with no
ordering guarantee — `tools/list` can easily arrive before `initialized`.

Remove the ~40-line wait loop and enter `serve_inner` immediately after
sending `InitializeResult`. The `initialized` notification is now
handled as a regular notification by the main service loop, matching the
TypeScript SDK behavior (validated in typescript-sdk#578).

Also remove the now-unreachable `ExpectedInitializedNotification` error
variant from `ServerInitializeError`.

Closes #783

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(server): keep ExpectedInitializedNotification as deprecated

Retain the variant for semver compatibility — removing it would be a
breaking change caught by cargo-semver-checks. Mark it deprecated with
a note that it is never constructed and will be removed in a future
major release.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Anar Azadaliyev <anar.azadaliye@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-09 19:23:59 -04:00
..
src fix(server): remove initialized notification gate to support Streamable HTTP (#788) 2026-04-09 19:23:59 -04:00
tests fix(server): remove initialized notification gate to support Streamable HTTP (#788) 2026-04-09 19:23:59 -04:00
build.rs chore: add pre-commit hook for conventional commit verification (#619) 2026-01-14 16:01:28 -05:00
Cargo.toml feat(transport): add which_command for cross-platform executable resolution (#774) 2026-04-07 06:58:23 -04:00
CHANGELOG.md chore: release v1.3.0 (#747) 2026-03-26 11:31:13 -04:00
README.md feat: add local feature for !Send tool handler support (#740) 2026-03-11 17:22:56 -04:00

README.md

rmcp

Crates.io Documentation

The official Rust SDK for the Model Context Protocol. Build MCP servers that expose tools, resources, and prompts to AI assistants — or build clients that connect to them.

For getting started, usage guides, and full MCP feature documentation (resources, prompts, sampling, roots, logging, completions, subscriptions, etc.), see the main README.

Feature Flags

Feature Description Default
server Server functionality and the tool system ✅
client Client functionality
macros #[tool] / #[prompt] macros (re-exports rmcp-macros) ✅
schemars JSON Schema generation for tool definitions
auth OAuth 2.0 authentication support
elicitation Elicitation support

Transport features

Feature Description
transport-io Server-side stdio transport
transport-child-process Client-side stdio transport (spawns a child process)
transport-async-rw Generic async read/write transport
transport-streamable-http-client Streamable HTTP client (transport-agnostic)
transport-streamable-http-client-reqwest Streamable HTTP client with default reqwest backend
transport-streamable-http-server Streamable HTTP server transport

TLS backend options (for HTTP transports)

Feature Description
reqwest Uses rustls — pure Rust TLS (recommended default)
reqwest-native-tls Uses platform-native TLS (OpenSSL / Secure Transport / SChannel)
reqwest-tls-no-provider Uses rustls without a default crypto provider (bring your own)

Transports

The transport layer is pluggable. Two built-in pairs cover the most common cases:

Client Server
stdio TokioChildProcess stdio
Streamable HTTP StreamableHttpClientTransport StreamableHttpService

Any type that implements the Transport trait can be used. The IntoTransport helper trait provides automatic conversions from:

  1. (Sink, Stream) or a combined Sink + Stream
  2. (AsyncRead, AsyncWrite) or a combined AsyncRead + AsyncWrite
  3. A Worker implementation
  4. A Transport implementation directly

License

This project is licensed under the terms specified in the repository's LICENSE file.