* 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>
Re-applies #919 (reverted by #932): ToolResultContent.structured_content
becomes Option<Value> so non-object structured content is accepted,
matching CallToolResult and SEP-2106.
BREAKING CHANGE: ToolResultContent.structured_content changes from
Option<JsonObject> to Option<Value>.
* fix: interpret task ttl as milliseconds
* fix: use text/plain for default text mime type
* fix: include resource param in token refresh
* test: align conformance prompt args with runner
* ci: run server conformance suite on PRs
* ci: build client bin and gate pending scenarios
Expose typed accessors for the per-request protocol version, client info,
client capabilities, and log level entries carried in _meta without making
those fields required for older peers.
Fixes#869
The spec's prompt-message ContentBlock union is
`text | image | audio | resource_link | resource`, but
PromptMessageContent omitted `Audio`. Because the enum is
`#[serde(tag = "type")]` with no catch-all, a spec-conformant
`{"type":"audio",...}` content block failed to deserialize with
"unknown variant `audio`", breaking prompts/get for any server that
returns audio prompt content (the audio analogue of #842 / #843).
The supporting AudioContent type already existed, and Audio was
already a variant of the general RawContent enum (tool results,
sampling) -- only PromptMessageContent lacked it.
Add the flattened Audio variant (mirroring Image), a
PromptMessage::new_audio constructor (mirroring new_image), and
serialization + deserialization regression tests.
Fixes#864.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
* 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).
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.
* feat: add theme field to Icon
* fix: update IconThem crates/rmcp/src/model.rs (non_exhaustive)
Co-authored-by: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
* fix: update IconThem crates/rmcp/src/model.rs (eq, hash)
Co-authored-by: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
* fix: update docs with full descriptions of theme from mcp spec
---------
Co-authored-by: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
The `#[serde(default)]` on `CallToolResult.content` (added in #752) made
all fields optional, causing `CallToolResult` to greedily match any JSON
object during `#[serde(untagged)]` deserialization of `ServerResult`.
Similarly, `GetTaskPayloadResult(Value)` matched everything before
`CustomResult(Value)` could be reached.
Fix by replacing derived `Deserialize` impls with custom ones:
- `CallToolResult`: require at least one known field to be present
- `GetTaskPayloadResult`: always fail (indistinguishable from
`CustomResult` in JSON; construct programmatically via `::new()`)
* fix: builder with_* methods take T instead of Option<T>
* fix: emit conditional builder calls for optional fields in macros
* fix: convert with_task, with_stop_reason, with_logger, with_content to proper builders
* fix: update test callers for new builder signatures
* fix: simplify make_task helper and remove unused import
* fix: update sampling_stdio example for new with_stop_reason signature
* fix: make annotations and execution Option<Expr> consistent with other fields
* fix: remove unused none_expr import
Add support for MCP extension capabilities in both ClientCapabilities
and ServerCapabilities structs, as specified in SEP-1724.
Changes:
- Add ExtensionCapabilities type alias (BTreeMap<String, JsonObject>)
- Add 'extensions' field to ClientCapabilities struct
- Add 'extensions' field to ServerCapabilities struct
- Update builder macros and impl blocks for both structs
- Add comprehensive tests for extension capabilities
- Update JSON schema test fixtures
This enables clients to advertise extension support during initialize,
such as:
{
"capabilities": {
"extensions": {
"io.modelcontextprotocol/ui": {
"mimeTypes": ["text/html;profile=mcp-app"]
}
}
}
}
Closes#530
* feat: implement SEP-1319 Decouple Request Payload from RPC Methods
* test: update tests
* fix: update handler trait methods to use new types
* fix: update examples
* fix: correct deprecation version
* fix: update wrapper macros to use new *Params type names
#580 and #556 introduced support for custom notifications,
so this PR takes the next logical step and adds support for custom requests:
- Introduces `CustomRequest` and `CustomResult` model types, wires them into the client/server
request and result unions, and allows `ClientRequest::method()` to return the dynamic method
name.
- Implements serde and meta handling for `CustomRequest` so `_meta` is carried through
extensions; adds default `on_custom_request` handlers that return `METHOD_NOT_FOUND` unless
overridden.
- Updates JSON schema fixtures to include the new request/result shapes and `EmptyObject`
strictness.
- Adds tests for custom request roundtrips and end-to-end client↔server handling.
- Focused integration test in `crates/rmcp/tests/test_custom_request.rs`.
For additional testing, I used this locally to update Codex to use a custom
request instead of a custom notification so that it gets an "ack" from the MCP
server to ensure it has processed the update before sending more messages:
https://github.com/openai/codex/pull/8142.
https://github.com/modelcontextprotocol/rust-sdk/pull/556 introduced support for
custom client notifications, so this PR makes the complementary change, adding
support for custom server notifications.
MCP clients, particularly ones that offer "experimental" capabilities,
may wish to handle custom server notifications that are not part of the
standard MCP specification. This change introduces a new
`CustomServerNotification` type that allows a client to process
such custom notifications.
- introduces `CustomServerNotification` to carry arbitrary methods/params while
still preserving meta/extensions; wires it into the `ServerNotification` union
and `serde` so `params` can be decoded with `params_as`
- allows client handlers to receive custom notifications via a new
`on_custom_notification` hook
- adds integration coverage that sends a custom server notification end-to-end
and asserts the client sees the method and payload
Test:
```shell
cargo test -p rmcp --features client test_custom_server_notification_reaches_client
```
MCP servers, particularly ones that offer "experimental" capabilities,
may wish to handle custom client notifications that are not part of the
standard MCP specification. This change introduces a new
`CustomClientNotification` type that allows a server to process
such custom notifications.
- introduces `CustomClientNotification` to carry arbitrary methods/params while
still preserving meta/extensions; wires it into the `ClientNotification` union
and `serde` so `params` can be decoded with `params_as`
- allows server handlers to receive custom notifications via a new
`on_custom_notification` hook
- adds integration coverage that sends a custom client notification end-to-end
and asserts the server sees the method and payload
Test:
```shell
cargo test -p rmcp --features client test_custom_client_notification_reaches_server
```
* feat: add type-safe elicitation schema support (#465)
Implement type-safe schema definitions for MCP elicitation requests,
replacing generic `JsonObject` with strongly-typed primitive schemas
per the [MCP 2025-06-18 specification](https://spec.modelcontextprotocol.io/specification/2025-06-18/server/elicitation/).
Features:
- Type-safe schema hierarchy (`StringSchema`, `NumberSchema`, `IntegerSchema`, `BooleanSchema`)
- Builder pattern with fluent API and 20+ convenience methods
- Build-time validation ensuring required fields exist in properties
- Private fields enforcing invariants through validated constructors
- Comprehensive validation support (range, length, format, enums)
- Typed property methods for cleaner schema construction
Benefits:
- Compile-time type safety prevents invalid schema construction
- 60-70% reduction in boilerplate through convenience methods
- Enforces MCP specification requirement for primitive-only properties
- Better IDE autocomplete and type inference
- Runtime validation catches schema errors early
Breaking changes:
- `CreateElicitationRequestParam.requested_schema` changed from `JsonObject` to `ElicitationSchema`
- `ElicitationSchemaBuilder::build()` now returns `Result` instead of direct value
Fixes#465
* fix: fix RMCP compliance
* feat: add conversion methods to ElicitationSchema
Add from_json_schema() and from_type() methods to ElicitationSchema
for easier type-to-schema conversion. This addresses feedback about
improving ergonomics when working with generated schemas.
Also make all struct fields public for better flexibility.
* chore: change `StringFormat` to enum
