History

Brandon Bennett 9e3de344f4 feat: relax outputSchema to accept non-object JSON Schema types (SEP-2106) (#895 ) * fix: address PR review - schema_for_output no longer validates or returns Result - Add strip_output() that strips title/description without validating type (Dale #1) - Change schema_for_output to return Arc<JsonObject> instead of Result (Dale #2) - Cache only Arc<JsonObject> success values, not Result (Dale #3) - Remove dead unwrap_or_else panic paths in with_output_schema, ToolBase, and macros - Tighten test assertions from contains to assert_eq on type field (Dale #4) - Update test_schema_for_output_rejects_primitive to accept_primitive (SEP-2106) Co-authored-by: Orca <help@stably.ai> * test(rmcp): add non-object output schema tests for SEP-2106 Add tests verifying schema_for_output accepts non-object types: - test_tool_builder_methods: primitive (i32), array (Vec<String>), option - test_structured_output: tool returning Json<Vec<T>> and Json<i32> - test_json_schema_detection: Json<Vec<T>>, Result<Json<Vec<T>>,E>, Json<String> - tool_traits: ToolBase::output_schema with Vec<AddOutput> output type * test(rmcp): add missing edge case tests from code review Add tests identified during code review: - description stripping for primitive types - composition types (Option<String> with anyOf/oneOf/null) - cache correctness (Arc::ptr_eq for repeated calls) - schema_for_input rejecting array types (not just primitives) - schema_for_output accepting unit type () * feat!: mark schema_for_output return-type change as breaking This introduces SEP-2106: schema_for_output no longer validates or returns Result. The public signature changed, so bump major. * fix: address Dale's PR review - direct schema.get assertions, remove ArrayTool - Replace loose schema_str.contains(...) assertions with direct schema.get("type") equality checks in test_tool_builder_methods.rs and test_structured_output.rs - Remove redundant ArrayTool fixture and its round-trip serde_json::from_str test from tool_traits.rs since schema is already Arc<JsonObject> - Drop dead schema_str variable in test_structured_output.rs --------- Co-authored-by: Brandon Bennett <brandonbennett@macbookair.myfiosgateway.com> Co-authored-by: Orca <help@stably.ai> Co-authored-by: Brandon Bennett <brandonbennett@Pursuits-Air.lan>		2026-07-08 14:19:28 -04:00
..
src	feat: relax outputSchema to accept non-object JSON Schema types (SEP-2106) (#895 )	2026-07-08 14:19:28 -04:00
tests	feat: relax outputSchema to accept non-object JSON Schema types (SEP-2106) (#895 )	2026-07-08 14:19:28 -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: add SEP-414 trace context meta accessors (#910 )	2026-07-01 16:51:05 -04:00
CHANGELOG.md	chore: release v2.2.0 (#953 )	2026-07-08 13:24:21 -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

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:

(Sink, Stream) or a combined Sink + Stream
(AsyncRead, AsyncWrite) or a combined AsyncRead + AsyncWrite
A Worker implementation
A Transport implementation directly

License

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