* fix(elicitation): preserve enumNames through ElicitationSchema serde round-trip
UntitledSingleSelectEnumSchema lacked deny_unknown_fields, so a legacy
enum payload containing enumNames was silently matched by that variant
(ignoring the field) rather than falling through to LegacyEnumSchema.
The enumNames array was lost on re-serialization.
Add deny_unknown_fields to UntitledSingleSelectEnumSchema so that any
unknown field (including enumNames) causes serde to try the next
untagged variant, reaching LegacyEnumSchema correctly.
Also add skip_serializing_if = "Option::is_none" to
LegacyEnumSchema::enum_names so that an untitled legacy enum without
enumNames does not serialize "enumNames": null.
Fixes#903
* test(elicitation): regenerate server schema snapshot for deny_unknown_fields
deny_unknown_fields on UntitledSingleSelectEnumSchema makes schemars
emit additionalProperties: false for that definition. Regenerate the
golden schema fixtures to match (UPDATE_SCHEMA=1 cargo test -p rmcp
--test test_message_schema --all-features).
* docs(server): document Err vs Ok(CallToolResult::error) visibility contract
The MCP spec separates two failure modes that surface very differently in
clients:
- Err(ErrorData) is a JSON-RPC protocol error. Most MCP clients render
it opaquely ("Tool result missing due to internal error") - the
caller does not see the message text.
- Ok(CallToolResult::error(content)) is a tool-level error. Clients
render the content; the caller reads the message.
The right shape for "the tool didn't work" is the latter, but Err is
what most handlers reach for because it looks like the natural Rust
return value. This commit adds rustdoc on both ServerHandler::call_tool
and CallToolResult::error pointing handlers at the correct shape, with
a worked example showing protocol errors (-32602 invalid_params) vs
tool errors (empty result, downstream failure).
This is the docs half of the visibility-contract ask. A follow-up may
introduce a typed ToolOutcome sum type to enforce the distinction at
compile time; this PR is the lower-risk version that unblocks the
class immediately.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* docs: update crates/rmcp/src/handler/server.rs
* docs: update crates/rmcp/src/model.rs
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
* feat: implement SEP-2164 resource not found errors
* test: update protocol version utility expectations
* feat: gate not-found code at server boundary
---------
Co-authored-by: Michael Neale <michael.neale@gmail.com>
* feat(auth): specify OIDC application_type during client registration
SEP-837 [1] requires an MCP client to specify an application_type during
OIDC Dynamic Client Registration. When it is omitted, OIDC servers
default the client to "web", which conflicts with the loopback redirect
URIs that CLI and desktop clients use, so the registration can be
rejected.
I make register_client always send an application_type. It defaults to
"native" to match the loopback redirect this SDK uses, and I added
OAuthClientConfig::with_application_type so web clients can opt in. Tests
cover the serialized request body and the config default. Implements [2].
[1]: https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/docs/specification/draft/basic/authorization.mdx#L395
[2]: https://github.com/modelcontextprotocol/rust-sdk/issues/880
Signed-off-by: Stefano Amorelli <stefano@amorelli.tech>
* chore(auth): declare application_type in client metadata document
I set application_type to "native" in the hosted client metadata
document so the URL-based client id flow and dynamic registration agree
on the client type that SEP-837 [1] expects.
[1]: https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/docs/specification/draft/basic/authorization.mdx#L395
Signed-off-by: Stefano Amorelli <stefano@amorelli.tech>
---------
Signed-off-by: Stefano Amorelli <stefano@amorelli.tech>
SEP-2577 deprecates the Roots, Sampling, and Logging features. The
deprecation is advisory: the features stay fully functional and there is
no wire-level change. Mark the corresponding Rust APIs as deprecated so
downstream users get compiler warnings and migration guidance.
- Forward attributes through the service `method!` macros and deprecate
`Peer::create_message`, `Peer::list_roots`, `Peer::set_level`, and
`Peer::notify_logging_message`.
- Forward per-field attributes through the capability `builder!` macro and
deprecate the generated `enable_roots`, `enable_sampling`, and
`enable_logging` builders, plus the hand-written
`enable_roots_list_changed`, `enable_sampling_tools`, and
`enable_sampling_context`.
- Document the deprecation on the capability types and fields, and in the
README feature sections.
- Allow `deprecated` at the crate's own call sites so the build stays
warning-clean, and refresh the message schema snapshots.
The Resource variant of PromptMessageContent was missing #[serde(flatten)],
causing the embedded resource content block to serialize as a double-nested
shape `{ "type": "resource", "resource": { "resource": {...} } }` instead of
the spec-compliant flat shape `{ "type": "resource", "resource": {uri, mimeType, text} }`.
This caused Zod-based MCP clients (e.g. Claude Code) to reject prompts/get
responses containing embedded resource messages with InvalidUnion errors.
The Image and ResourceLink variants already use #[serde(flatten)] correctly;
only Resource was missing it.
Fix: add #[serde(flatten)] so EmbeddedResource (=Annotated<RawEmbeddedResource>)
fields _meta / annotations / resource are flattened to the content-block level,
matching the MCP spec for prompts embedded resources.
Regression test: test_prompt_message_resource_serialization_is_flat verifies
content.resource.uri is reachable and content.resource.resource is absent.
Schema snapshots regenerated via UPDATE_SCHEMA=1.
* fix(transport): downgrade idle timeout log from error to debug
Idle keep-alive timeout is normal zombie-session cleanup, not a transport failure.
Route it through a dedicated WorkerQuitReason::IdleTimeout variant.
Log it at debug level instead of treating it as a fatal error.
Remove the unused LocalSessionWorkerError::KeepAliveTimeout variant.
Closes#817
* fix(session): tolerate dead worker in close_session
Swallow SessionServiceTerminated in close_session when the worker has already exited.
This prevents a spurious ERROR log during the post-exit cleanup path in
spawn_session_worker.
* fix(transport): address PR review feedback
- deprecate KeepAliveTimeout
- harden tests
* feat(router): support runtime disabling of tools
Add methods to disable/enable tools at runtime.
Disabled tools are hidden from listing, lookup,
and execution, including in composed routers.
Closes#477
* fix(router): simplify disable tool api
* feat(router): auto-send tools/list_changed on disable/enable
* refactor(router): simplify disable_route and notifier call
The README examples used `#[tool(param)]` on function parameters,
which is not a supported syntax and fails to compile. Replace with
the `Parameters<T>` wrapper pattern that the macros actually expect.
Closes#812
In fetch_resource_metadata_from_url, a JSON parse failure on the
response body caused a fatal AuthError::MetadataError, preventing
discover_metadata() from falling through to direct
.well-known/oauth-authorization-server discovery (Strategy B).
MCP servers that return HTTP 200 with non-JSON content (e.g. HTML)
at their base URL caused the OAuth flow to abort entirely, even
when the server had a valid .well-known/oauth-authorization-server
endpoint.
Return Ok(None) on parse failure, consistent with how HTTP errors
are already handled in the same function.
* fix: include http_request_id in request-wise priming event IDs
* refactor: use Option::into_iter and usize::from for priming
* fix: retain event cache for completed request-wise channels
* fix: track completed_at for cache eviction and resume
* fix: log resume failures at warn level
* test: add completed_cache_ttl eviction test
* fix: return empty stream on failed resume
* test: add resume after completion test
* fix(http): reduce latency on subsequent StreamableHttp calls
* refactor: rely on stream drain for connection reuse
* refactor: clean up comments and naming
* fix: restore pool_max_idle_per_host(0) for Linux
AuthRequiredError, InsufficientScopeError, and DynamicTransportError
were marked #[non_exhaustive] in #715/#768 but don't have constructors
usable by external crates. Add new() for the error types and
from_parts() for DynamicTransportError (the existing new() requires a
Transport type parameter, making it unusable for test fixtures).
Fixes#805
* 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>
