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

conformance/src/bin/server.rs

@@ -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.",
             )])),
@@ -530,7 +530,8 @@ impl ServerHandler for ConformanceServer {
                 format!("Unknown tool: {}", request.name),
                 None,
             )),
-        }
+        };
+        result.map(Into::into)
     }
 
     async fn list_resources(
@@ -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(),
@@ -598,7 +599,8 @@ impl ServerHandler for ConformanceServer {
                     ))
                 }
             }
-        }
+        };
+        result.map(Into::into)
     }
 
     async fn list_resource_templates(
@@ -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.",
@@ -724,7 +726,8 @@ impl ServerHandler for ConformanceServer {
                 format!("Unknown prompt: {}", request.name),
                 None,
             )),
-        }
+        };
+        result.map(Into::into)
     }
 
     async fn complete(

crates/rmcp-macros/src/prompt_handler.rs

@@ -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,

crates/rmcp-macros/src/tool_handler.rs

@@ -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
             }

crates/rmcp/src/handler/server.rs

@@ -26,6 +26,9 @@ 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)
@@ -45,7 +48,7 @@ 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
@@ -61,7 +64,7 @@ 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
@@ -104,7 +107,7 @@ 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
@@ -132,6 +135,17 @@ 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.
@@ -223,7 +237,7 @@ 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(
@@ -253,7 +267,7 @@ 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>(),
             ))
@@ -306,7 +320,7 @@ 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(
@@ -479,7 +493,7 @@ 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)
             }
 
@@ -512,7 +526,7 @@ 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)
             }
 
@@ -536,7 +550,7 @@ 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 + '_ {
                 (**self).call_tool(request, context)
             }
 

crates/rmcp/src/handler/server/prompt.rs

@@ -15,7 +15,7 @@ pub use super::common::{Extension, RequestId};
 use crate::{
     RoleServer,
     handler::server::wrapper::Parameters,
-    model::{GetPromptResult, PromptMessage},
+    model::{GetPromptResponse, GetPromptResult, InputRequiredResult, PromptMessage},
     service::{MaybeBoxFuture, MaybeSend, MaybeSendFuture, RequestContext},
 };
 
@@ -59,12 +59,12 @@ pub trait GetPromptHandler<S, A> {
     fn handle(
         self,
         context: PromptContext<'_, S>,
-    ) -> MaybeBoxFuture<'_, Result<GetPromptResult, crate::ErrorData>>;
+    ) -> MaybeBoxFuture<'_, Result<GetPromptResponse, crate::ErrorData>>;
 }
 
 /// Type alias for dynamic prompt handlers
 #[cfg(not(feature = "local"))]
-pub type DynGetPromptHandler<S> = dyn for<'a> Fn(PromptContext<'a, S>) -> BoxFuture<'a, Result<GetPromptResult, crate::ErrorData>>
+pub type DynGetPromptHandler<S> = dyn for<'a> Fn(PromptContext<'a, S>) -> BoxFuture<'a, Result<GetPromptResponse, crate::ErrorData>>
     + Send
     + Sync;
 
@@ -73,7 +73,7 @@ pub type DynGetPromptHandler<S> = dyn for<'a> Fn(
     PromptContext<'a, S>,
 ) -> futures::future::LocalBoxFuture<
     'a,
-    Result<GetPromptResult, crate::ErrorData>,
+    Result<GetPromptResponse, crate::ErrorData>,
 >;
 
 /// Adapter type for async methods that return `Vec<PromptMessage>`
@@ -91,28 +91,35 @@ pub struct SyncPromptMethodAdapter<P, R>(PhantomData<fn(P) -> R>);
 
 /// Trait for types that can be converted into GetPromptResult
 pub trait IntoGetPromptResult {
-    fn into_get_prompt_result(self) -> Result<GetPromptResult, crate::ErrorData>;
+    fn into_get_prompt_result(self) -> Result<GetPromptResponse, crate::ErrorData>;
 }
 
 impl IntoGetPromptResult for GetPromptResult {
-    fn into_get_prompt_result(self) -> Result<GetPromptResult, crate::ErrorData> {
-        Ok(self)
+    fn into_get_prompt_result(self) -> Result<GetPromptResponse, crate::ErrorData> {
+        Ok(self.into())
+    }
+}
+
+impl IntoGetPromptResult for InputRequiredResult {
+    fn into_get_prompt_result(self) -> Result<GetPromptResponse, crate::ErrorData> {
+        Ok(self.into())
     }
 }
 
 impl IntoGetPromptResult for Vec<PromptMessage> {
-    fn into_get_prompt_result(self) -> Result<GetPromptResult, crate::ErrorData> {
+    fn into_get_prompt_result(self) -> Result<GetPromptResponse, crate::ErrorData> {
         Ok(GetPromptResult {
             result_type: Default::default(),
             description: None,
             messages: self,
             meta: None,
-        })
+        }
+        .into())
     }
 }
 
 impl<T: IntoGetPromptResult> IntoGetPromptResult for Result<T, crate::ErrorData> {
-    fn into_get_prompt_result(self) -> Result<GetPromptResult, crate::ErrorData> {
+    fn into_get_prompt_result(self) -> Result<GetPromptResponse, crate::ErrorData> {
         self.and_then(|v| v.into_get_prompt_result())
     }
 }
@@ -129,7 +136,7 @@ pin_project_lite::pin_project! {
         },
         Ready {
             #[pin]
-            result: futures::future::Ready<Result<GetPromptResult, crate::ErrorData>>,
+            result: futures::future::Ready<Result<GetPromptResponse, crate::ErrorData>>,
         }
     }
 }
@@ -139,7 +146,7 @@ where
     F: Future<Output = R>,
     R: IntoGetPromptResult,
 {
-    type Output = Result<GetPromptResult, crate::ErrorData>;
+    type Output = Result<GetPromptResponse, crate::ErrorData>;
 
     fn poll(
         self: std::pin::Pin<&mut Self>,
@@ -216,7 +223,7 @@ macro_rules! impl_prompt_handler_for {
             fn handle(
                 self,
                 mut context: PromptContext<'_, S>,
-            ) -> MaybeBoxFuture<'_, Result<GetPromptResult, crate::ErrorData>>
+            ) -> MaybeBoxFuture<'_, Result<GetPromptResponse, crate::ErrorData>>
             {
                 $(
                     let result = $Tn::from_context_part(&mut context);
@@ -249,7 +256,7 @@ macro_rules! impl_prompt_handler_for {
             fn handle(
                 self,
                 mut context: PromptContext<'_, S>,
-            ) -> MaybeBoxFuture<'_, Result<GetPromptResult, crate::ErrorData>>
+            ) -> MaybeBoxFuture<'_, Result<GetPromptResponse, crate::ErrorData>>
             {
                 $(
                     let result = $Tn::from_context_part(&mut context);
@@ -280,7 +287,7 @@ macro_rules! impl_prompt_handler_for {
             fn handle(
                 self,
                 mut context: PromptContext<'_, S>,
-            ) -> MaybeBoxFuture<'_, Result<GetPromptResult, crate::ErrorData>>
+            ) -> MaybeBoxFuture<'_, Result<GetPromptResponse, crate::ErrorData>>
             {
                 // Extract all parameters before moving into the async block
                 $(
@@ -315,7 +322,7 @@ macro_rules! impl_prompt_handler_for {
             fn handle(
                 self,
                 mut context: PromptContext<'_, S>,
-            ) -> MaybeBoxFuture<'_, Result<GetPromptResult, crate::ErrorData>>
+            ) -> MaybeBoxFuture<'_, Result<GetPromptResponse, crate::ErrorData>>
             {
                 $(
                     let result = $Tn::from_context_part(&mut context);

crates/rmcp/src/handler/server/router.rs

@@ -106,7 +106,7 @@ where
                         context,
                     );
                     let result = self.tool_router.call(tool_call_context).await?;
-                    Ok(ServerResult::CallToolResult(result))
+                    Ok(ServerResult::from(result))
                 } else {
                     self.service
                         .handle_request(ClientRequest::CallToolRequest(request), context)
@@ -129,7 +129,7 @@ where
                         context,
                     );
                     let result = self.prompt_router.get_prompt(prompt_context).await?;
-                    Ok(ServerResult::GetPromptResult(result))
+                    Ok(ServerResult::from(result))
                 } else {
                     self.service
                         .handle_request(ClientRequest::GetPromptRequest(request), context)
@@ -193,7 +193,7 @@ mod tests {
     async fn test_router_deferred_notifier_e2e() {
         let mut router = Router::new(DummyHandler).with_tool(tool::ToolRoute::new_dyn(
             Tool::new("my_tool", "test", Arc::new(Default::default())),
-            |_ctx| Box::pin(async { Ok(CallToolResult::default()) }),
+            |_ctx| Box::pin(async { Ok(CallToolResult::default().into()) }),
         ));
 
         let id_provider: Arc<dyn RequestIdProvider> =

crates/rmcp/src/handler/server/router/prompt.rs

@@ -2,7 +2,7 @@ use std::{borrow::Cow, sync::Arc};
 
 use crate::{
     handler::server::prompt::{DynGetPromptHandler, GetPromptHandler, PromptContext},
-    model::{GetPromptResult, Prompt},
+    model::{GetPromptResponse, Prompt},
     service::{MaybeBoxFuture, MaybeSend},
 };
 
@@ -50,7 +50,8 @@ impl<S: MaybeSend + 'static> PromptRoute<S> {
     where
         H: for<'a> Fn(
                 PromptContext<'a, S>,
-            ) -> MaybeBoxFuture<'a, Result<GetPromptResult, crate::ErrorData>>
+            )
+                -> MaybeBoxFuture<'a, Result<GetPromptResponse, crate::ErrorData>>
             + MaybeSend
             + 'static,
     {
@@ -175,7 +176,7 @@ where
     pub async fn get_prompt(
         &self,
         context: PromptContext<'_, S>,
-    ) -> Result<GetPromptResult, crate::ErrorData> {
+    ) -> Result<GetPromptResponse, crate::ErrorData> {
         let item = self.map.get(context.name.as_str()).ok_or_else(|| {
             crate::ErrorData::invalid_params(
                 format!("prompt '{}' not found", context.name),