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Merged
DaleSeo merged 3 commits into from
Jul 10, 2026
Merged

feat!: add MRTR behavior support (SEP-2322) #929

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1c97de6
feat!: add MRTR behavior support
DaleSeo Jun 26, 2026
4dbf0b4
feat: harden SEP-2322 MRTR support
DaleSeo Jul 2, 2026
c288c86
ci: diff public API only on features common to base and head
DaleSeo Jul 8, 2026
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24 changes: 19 additions & 5 deletions .github/workflows/ci.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -170,18 +170,32 @@ jobs:

- name: Check rmcp (all features except local)
run: |
FEATURES=$(cargo metadata --no-deps --format-version 1 \
| jq -r '[.packages[] | select(.name == "rmcp") | .features | keys[]
| select(startswith("__") | not)
| select(. != "local")] | join(",")')
BASE_SHA=${{ github.event.pull_request.base.sha }}
# `cargo public-api diff` builds both revisions with the same feature
# set, so a feature that exists on only one side (e.g. a feature added
# or removed by this PR) would fail to build the other revision. Diff
# only the features present in BOTH the base and the head; features
# unique to one side are necessarily pure additions/removals, which the
# release-type deny flags already govern.
list_features() {
cargo metadata --no-deps --format-version 1 --manifest-path "$1/Cargo.toml" \
| jq -r '.packages[] | select(.name == "rmcp") | .features | keys[]
| select(startswith("__") | not)
| select(. != "local")'
}
list_features "." | sort -u > "$RUNNER_TEMP/head_features"
git worktree add --detach "$RUNNER_TEMP/rmcp-base" "$BASE_SHA"
list_features "$RUNNER_TEMP/rmcp-base" | sort -u > "$RUNNER_TEMP/base_features"
git worktree remove --force "$RUNNER_TEMP/rmcp-base"
FEATURES=$(comm -12 "$RUNNER_TEMP/head_features" "$RUNNER_TEMP/base_features" | paste -sd, -)
cargo public-api \
--package rmcp \
--features "$FEATURES" \
-ss \
diff \
$DENY \
--force \
${{ github.event.pull_request.base.sha }}..${{ github.sha }}
"$BASE_SHA"..${{ github.sha }}

spelling:
name: spell check with typos
Expand Down
21 changes: 12 additions & 9 deletions conformance/src/bin/server.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -213,9 +213,9 @@ impl ServerHandler for ConformanceServer {
&self,
request: CallToolRequestParams,
cx: RequestContext<RoleServer>,
) -> Result<CallToolResult, ErrorData> {
) -> Result<CallToolResponse, ErrorData> {
let args = request.arguments.unwrap_or_default();
match request.name.as_ref() {
let result = match request.name.as_ref() {
"test_simple_text" => Ok(CallToolResult::success(vec![ContentBlock::text(
"This is a simple text response for testing.",
)])),
Expand Down Expand Up @@ -530,7 +530,8 @@ impl ServerHandler for ConformanceServer {
format!("Unknown tool: {}", request.name),
None,
)),
}
};
result.map(Into::into)
}

async fn list_resources(
Expand All @@ -555,9 +556,9 @@ impl ServerHandler for ConformanceServer {
&self,
request: ReadResourceRequestParams,
_cx: RequestContext<RoleServer>,
) -> Result<ReadResourceResult, ErrorData> {
) -> Result<ReadResourceResponse, ErrorData> {
let uri = request.uri.as_str();
match uri {
let result = match uri {
"test://static-text" => Ok(ReadResourceResult::new(vec![
ResourceContents::TextResourceContents {
uri: uri.into(),
Expand Down Expand Up @@ -598,7 +599,8 @@ impl ServerHandler for ConformanceServer {
))
}
}
}
};
result.map(Into::into)
}

async fn list_resource_templates(
Expand Down Expand Up @@ -679,8 +681,8 @@ impl ServerHandler for ConformanceServer {
&self,
request: GetPromptRequestParams,
_cx: RequestContext<RoleServer>,
) -> Result<GetPromptResult, ErrorData> {
match request.name.as_str() {
) -> Result<GetPromptResponse, ErrorData> {
let result = match request.name.as_str() {
"test_simple_prompt" => Ok(GetPromptResult::new(vec![PromptMessage::new_text(
Role::User,
"This is a simple test prompt.",
Expand Down Expand Up @@ -721,7 +723,8 @@ impl ServerHandler for ConformanceServer {
format!("Unknown prompt: {}", request.name),
None,
)),
}
};
result.map(Into::into)
}

async fn complete(
Expand Down
2 changes: 1 addition & 1 deletion crates/rmcp-macros/src/prompt_handler.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ pub fn prompt_handler(attr: TokenStream, input: TokenStream) -> syn::Result<Toke
&self,
request: rmcp::model::GetPromptRequestParams,
context: rmcp::service::RequestContext<rmcp::RoleServer>,
) -> Result<rmcp::model::GetPromptResult, rmcp::ErrorData> {
) -> Result<rmcp::model::GetPromptResponse, rmcp::ErrorData> {
let prompt_context = rmcp::handler::server::prompt::PromptContext::new(
self,
request.name,
Expand Down
11 changes: 10 additions & 1 deletion crates/rmcp-macros/src/task_handler.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,16 @@ pub fn task_handler(attr: TokenStream, input: TokenStream) -> syn::Result<TokenS

let task_result_id = task_id.clone();
let future = Box::pin(async move {
let result = server.call_tool(future_request, future_context).await;
let result = server
.call_tool(future_request, future_context)
.await
.and_then(|response| match response {
rmcp::model::CallToolResponse::Complete(result) => Ok(result),
_ => Err(rmcp::ErrorData::internal_error(
"input_required is not supported for task-based tool calls",
None,
)),
});
Ok(
Box::new(ToolCallTaskResult::new(task_result_id, result))
as Box<dyn OperationResultTransport>,
Expand Down
2 changes: 1 addition & 1 deletion crates/rmcp-macros/src/tool_handler.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ pub fn tool_handler(attr: TokenStream, input: TokenStream) -> syn::Result<TokenS
&self,
request: rmcp::model::CallToolRequestParams,
context: rmcp::service::RequestContext<rmcp::RoleServer>,
) -> Result<rmcp::model::CallToolResult, rmcp::ErrorData> {
) -> Result<rmcp::model::CallToolResponse, rmcp::ErrorData> {
let tcc = rmcp::handler::server::tool::ToolCallContext::new(self, request, context);
#router.call(tcc).await
}
Expand Down
13 changes: 13 additions & 0 deletions crates/rmcp/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ features = [
"client-side-sse",
"elicitation",
"macros",
"request-state",
"reqwest",
"reqwest-native-tls",
"reqwest-tls-no-provider",
Expand Down Expand Up @@ -64,6 +65,10 @@ schemars = { version = "1.0", optional = true, features = ["chrono04"] }
# for image encoding
base64 = { version = "0.22", optional = true }

# for SEP-2322 requestState integrity sealing (opt-in via the `request-state` feature)
hmac = { version = "0.12", optional = true }
sha2 = { version = "0.10", optional = true }

# for HTTP client
reqwest = { version = "0.13.2", default-features = false, features = [
"json",
Expand Down Expand Up @@ -120,6 +125,9 @@ server = ["transport-async-rw", "dep:schemars", "dep:pastey"]
macros = ["dep:rmcp-macros", "dep:pastey"]
elicitation = ["dep:url"]

# SEP-2322 requestState integrity helper (HMAC-SHA256 seal/open codec)
request-state = ["dep:hmac", "dep:sha2", "base64"]

# reqwest http client
__reqwest = ["dep:reqwest"]

Expand Down Expand Up @@ -309,6 +317,11 @@ name = "test_trace_context"
required-features = ["server", "client"]
path = "tests/test_trace_context.rs"

[[test]]
name = "test_mrtr_behavior"
required-features = ["server", "client"]
path = "tests/test_mrtr_behavior.rs"

[[test]]
name = "test_prompt_macros"
required-features = ["server", "client"]
Expand Down
32 changes: 23 additions & 9 deletions crates/rmcp/src/handler/server.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,9 @@ impl<H: ServerHandler> Service<RoleServer> for H {
) -> Result<<RoleServer as ServiceRole>::Resp, McpError> {
// `context` is moved into the dispatch below, so read the negotiated version first.
let protocol_version = context.protocol_version();
let mrtr_supported = protocol_version
.as_ref()
.is_some_and(|v| v.as_str() >= ProtocolVersion::V_2026_07_28.as_str());
let result = match request {
ClientRequest::InitializeRequest(request) => self
.initialize(request.params, context)
Expand All @@ -46,7 +49,7 @@ impl<H: ServerHandler> Service<RoleServer> for H {
ClientRequest::GetPromptRequest(request) => self
.get_prompt(request.params, context)
.await
.map(ServerResult::GetPromptResult),
.map(ServerResult::from),
ClientRequest::ListPromptsRequest(request) => self
.list_prompts(request.params, context)
.await
Expand All @@ -62,7 +65,7 @@ impl<H: ServerHandler> Service<RoleServer> for H {
ClientRequest::ReadResourceRequest(request) => self
.read_resource(request.params, context)
.await
.map(ServerResult::ReadResourceResult),
.map(ServerResult::from),
ClientRequest::SubscribeRequest(request) => self
.subscribe(request.params, context)
.await
Expand Down Expand Up @@ -105,7 +108,7 @@ impl<H: ServerHandler> Service<RoleServer> for H {
} else {
self.call_tool(request.params, context)
.await
.map(ServerResult::CallToolResult)
.map(ServerResult::from)
}
}
ClientRequest::ListToolsRequest(request) => self
Expand Down Expand Up @@ -133,6 +136,17 @@ impl<H: ServerHandler> Service<RoleServer> for H {
.await
.map(ServerResult::CancelTaskResult),
};
let result = result.and_then(|result| {
if matches!(result, ServerResult::InputRequiredResult(_)) && !mrtr_supported {
Err(McpError::invalid_request(
"InputRequiredResult requires negotiated protocol version 2026-07-28 or newer",
None,
))
} else {
Ok(result)
}
});

// SEP-2164: peers negotiating 2026-07-28+ get the standard INVALID_PARAMS code for
// resource-not-found; older peers keep RESOURCE_NOT_FOUND. ISO `YYYY-MM-DD` versions
// compare lexically the same as chronologically.
Expand Down Expand Up @@ -229,7 +243,7 @@ macro_rules! server_handler_methods {
&self,
request: GetPromptRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<GetPromptResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<GetPromptResponse, McpError>> + MaybeSendFuture + '_ {
std::future::ready(Err(McpError::method_not_found::<GetPromptRequestMethod>()))
}
fn list_prompts(
Expand Down Expand Up @@ -259,7 +273,7 @@ macro_rules! server_handler_methods {
&self,
request: ReadResourceRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<ReadResourceResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<ReadResourceResponse, McpError>> + MaybeSendFuture + '_ {
std::future::ready(Err(
McpError::method_not_found::<ReadResourceRequestMethod>(),
))
Expand Down Expand Up @@ -312,7 +326,7 @@ macro_rules! server_handler_methods {
&self,
request: CallToolRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<CallToolResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<CallToolResponse, McpError>> + MaybeSendFuture + '_ {
std::future::ready(Err(McpError::method_not_found::<CallToolRequestMethod>()))
}
fn list_tools(
Expand Down Expand Up @@ -485,7 +499,7 @@ macro_rules! impl_server_handler_for_wrapper {
&self,
request: GetPromptRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<GetPromptResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<GetPromptResponse, McpError>> + MaybeSendFuture + '_ {
(**self).get_prompt(request, context)
}

Expand Down Expand Up @@ -518,7 +532,7 @@ macro_rules! impl_server_handler_for_wrapper {
&self,
request: ReadResourceRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<ReadResourceResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<ReadResourceResponse, McpError>> + MaybeSendFuture + '_ {
(**self).read_resource(request, context)
}

Expand All @@ -542,7 +556,7 @@ macro_rules! impl_server_handler_for_wrapper {
&self,
request: CallToolRequestParams,
context: RequestContext<RoleServer>,
) -> impl Future<Output = Result<CallToolResult, McpError>> + MaybeSendFuture + '_ {
) -> impl Future<Output = Result<CallToolResponse, McpError>> + MaybeSendFuture + '_ {

@alexhancock alexhancock Jul 1, 2026

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Thoughts on all these renames? Just wondering why the move from Result to Response

@DaleSeo DaleSeo Jul 1, 2026 •
edited
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@alexhancock Not a rename. CallToolResult, GetPromptResult, ReadResourceResult are unchanged. CallToolResponse is a new outcome enum mirroring what the spec's draft schema reference already models. Each method's response result is a union InputRequiredResult | CallToolResult. Rust has no anonymous unions, so I introduced one named enum per method to express that union at the handler return type.

Existing handlers don't need to change because the IntoCallToolResult conversions still accept a plain CallToolResult, Json<T>, Content, Result<T, E>, etc., and there are From<CallToolResult> / From<InputRequiredResult> impls, so .into() covers both arms. Only the trait-level return type widened.

(**self).call_tool(request, context)
}

Expand Down
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