fix(model): deprecate ServerInfo and ClientInfo aliases

README.md

@@ -99,10 +99,10 @@ Use [`ClientServiceExt::serve_with_lifecycle`](crates/rmcp/src/service/client.rs
 select another lifecycle explicitly:
 
 ```rust, ignore
-use rmcp::{ClientInfo, ClientLifecycleMode, ClientServiceExt, ProtocolVersion};
+use rmcp::{ClientLifecycleMode, ClientServiceExt, InitializeRequestParams, ProtocolVersion};
 
 // Start directly with server/discover and include client metadata on every request.
-let client = ClientInfo::default()
+let client = InitializeRequestParams::default()
     .serve_with_lifecycle(
         transport,
         ClientLifecycleMode::Discover {
@@ -113,7 +113,7 @@ let client = ClientInfo::default()
 
 // Or probe the discover lifecycle and fall back when a legacy server reports
 // that server/discover is not implemented.
-let client = ClientInfo::default()
+let client = InitializeRequestParams::default()
     .serve_with_lifecycle(
         transport,
         ClientLifecycleMode::Auto {
@@ -369,8 +369,8 @@ use serde_json::json;
 struct MyServer;
 
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(
             ServerCapabilities::builder()
                 .enable_resources()
                 .build(),
@@ -582,8 +582,8 @@ impl MyServer {
 
 #[prompt_handler]
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(ServerCapabilities::builder().enable_prompts().build())
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(ServerCapabilities::builder().enable_prompts().build())
     }
 }
 ```
@@ -934,8 +934,8 @@ Enable the logging capability, handle level changes from the client, and send lo
 use rmcp::{ServerHandler, model::*, service::RequestContext};
 
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(
             ServerCapabilities::builder()
                 .enable_logging()
                 .build(),
@@ -1007,8 +1007,8 @@ Enable the completions capability and implement the `complete()` handler. Use `r
 use rmcp::{ErrorData as McpError, ServerHandler, model::*, service::RequestContext, RoleServer};
 
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(
             ServerCapabilities::builder()
                 .enable_completions()
                 .enable_prompts()
@@ -1253,8 +1253,8 @@ use rmcp::{
 };
 
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(
             ServerCapabilities::builder()
                 .enable_tools()
                 .enable_tool_list_changed()
@@ -1574,7 +1574,7 @@ use rmcp::transport::StreamableHttpClientTransport;
 
 // Defaults are stateless-friendly.
 let transport = StreamableHttpClientTransport::from_uri("http://localhost:8000/mcp");
-let client = ClientInfo::default().serve(transport).await?;
+let client = InitializeRequestParams::default().serve(transport).await?;
 ```
 
 **Example:** [`examples/servers/src/counter_streamhttp.rs`](examples/servers/src/counter_streamhttp.rs) (server), [`examples/clients/src/streamable_http.rs`](examples/clients/src/streamable_http.rs) (client)
@@ -1628,7 +1628,7 @@ server example). The client transport connects with a single URI:
 use rmcp::transport::StreamableHttpClientTransport;
 
 let transport = StreamableHttpClientTransport::from_uri("http://localhost:8000/mcp");
-let client = ClientInfo::default().serve(transport).await?;
+let client = InitializeRequestParams::default().serve(transport).await?;
 ```
 
 #### Server-Sent Events (SSE)
@@ -1714,10 +1714,10 @@ knows what the other supports. Declare yours with the `ServerCapabilities`
 builder in `get_info()`:
 
 ```rust,ignore
-use rmcp::model::{ServerCapabilities, ServerInfo};
+use rmcp::model::{InitializeResult, ServerCapabilities};
 
-fn get_info(&self) -> ServerInfo {
-    ServerInfo::new(
+fn get_info(&self) -> InitializeResult {
+    InitializeResult::new(
         ServerCapabilities::builder()
             .enable_tools()
             .enable_prompts()

conformance/src/bin/client.rs

@@ -55,8 +55,8 @@ impl ClientHandler for BasicClientHandler {}
 struct ElicitationDefaultsClientHandler;
 
 impl ClientHandler for ElicitationDefaultsClientHandler {
-    fn get_info(&self) -> ClientInfo {
-        let mut info = ClientInfo::default();
+    fn get_info(&self) -> InitializeRequestParams {
+        let mut info = InitializeRequestParams::default();
         info.capabilities.elicitation = Some(
             ElicitationCapability::new()
                 .with_form(FormElicitationCapability::new().with_schema_validation(true)),
@@ -144,8 +144,8 @@ impl ClientHandler for ElicitationDefaultsClientHandler {
 struct FullClientHandler;
 
 impl ClientHandler for FullClientHandler {
-    fn get_info(&self) -> ClientInfo {
-        let mut info = ClientInfo::default();
+    fn get_info(&self) -> InitializeRequestParams {
+        let mut info = InitializeRequestParams::default();
         info.capabilities.elicitation = Some(
             ElicitationCapability::new()
                 .with_form(FormElicitationCapability::new().with_schema_validation(true)),

conformance/src/bin/server.rs

@@ -700,8 +700,8 @@ impl ServerHandler for ConformanceServer {
         (name == "test_custom_header").then(custom_header_tool)
     }
 
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(
             ServerCapabilities::builder()
                 .enable_prompts()
                 .enable_prompts_list_changed()

crates/rmcp-macros/src/lib.rs

@@ -185,8 +185,8 @@ pub fn tool_router(attr: TokenStream, input: TokenStream) -> TokenStream {
 /// ```rust,ignore
 /// #[tool_handler]
 /// impl ServerHandler for MyToolHandler {
-///     fn get_info(&self) -> ServerInfo {
-///         ServerInfo::new(ServerCapabilities::builder().enable_tools().build())
+///     fn get_info(&self) -> InitializeResult {
+///         InitializeResult::new(ServerCapabilities::builder().enable_tools().build())
 ///     }
 /// }
 /// ```

crates/rmcp-macros/src/tool_handler.rs

@@ -116,7 +116,7 @@ pub(crate) enum CallerCapability {
     Prompts,
 }
 
-/// Build a `get_info()` method that returns `ServerInfo` with the appropriate capabilities.
+/// Build a `get_info()` method that returns `InitializeResult` with the appropriate capabilities.
 ///
 /// The caller declares its own capability via `caller`. Sibling handler attributes
 /// (`prompt_handler`, `tool_handler`) are detected automatically
@@ -157,8 +157,8 @@ pub(crate) fn build_get_info(
     }
 
     syn::parse2::<ImplItem>(quote! {
-        fn get_info(&self) -> rmcp::model::ServerInfo {
-            rmcp::model::ServerInfo::new(
+        fn get_info(&self) -> rmcp::model::InitializeResult {
+            rmcp::model::InitializeResult::new(
                 rmcp::model::ServerCapabilities::builder()
                     #(#capability_calls)*
                     .build()

crates/rmcp/src/handler/client.rs

@@ -275,7 +275,7 @@ macro_rules! client_handler_methods {
         }
 
         fn get_info(&self) -> ClientInfo {
-            ClientInfo::default()
+            InitializeRequestParams::default()
         }
     };
 }

crates/rmcp/src/handler/server.rs

@@ -551,7 +551,7 @@ macro_rules! server_handler_methods {
         }
 
         fn get_info(&self) -> ServerInfo {
-            ServerInfo::default()
+            InitializeResult::default()
         }
 
         /// SEP-2663 `tasks/get`: return the current [`DetailedTask`] state.

crates/rmcp/src/model.rs

@@ -1082,7 +1082,26 @@ impl InitializeResult {
     }
 }
 
+/// Full server initialize payload (`InitializeResult`).
+///
+/// Prefer [`InitializeResult`]. The name collides with the protocol's
+/// `serverInfo` field, which is only the [`Implementation`] identity (#1082).
+//
+// The signatures this crate publishes (`ServerHandler::get_info`,
+// `DiscoverResult::from_server_info`, and the `ClientInfo` equivalents below)
+// keep spelling the alias. It resolves to the same type, so the spelling makes
+// no difference to callers, but rustdoc records the name as written and the
+// public API check treats a respelling as a changed item. Moving those
+// signatures onto the canonical names is a documented API change and belongs in
+// the next major release.
+#[deprecated(note = "use `InitializeResult` instead")]
 pub type ServerInfo = InitializeResult;
+
+/// Full client initialize params (`InitializeRequestParams`).
+///
+/// Prefer [`InitializeRequestParams`]. The name collides with the protocol's
+/// `clientInfo` field, which is only the [`Implementation`] identity (#1082).
+#[deprecated(note = "use `InitializeRequestParams` instead")]
 pub type ClientInfo = InitializeRequestParams;
 
 /// Information negotiated about a server peer.
@@ -1247,7 +1266,7 @@ impl DiscoverResult {
         supported_versions: Vec<ProtocolVersion>,
         server_info: ServerInfo,
     ) -> Self {
-        let ServerInfo {
+        let InitializeResult {
             capabilities,
             server_info,
             instructions,
@@ -1295,9 +1314,9 @@ impl ServerPeerInfo {
 }
 
 #[allow(clippy::derivable_impls)]
-impl Default for ServerInfo {
+impl Default for InitializeResult {
     fn default() -> Self {
-        ServerInfo {
+        InitializeResult {
             protocol_version: ProtocolVersion::default(),
             capabilities: ServerCapabilities::default(),
             server_info: Implementation::from_build_env(),
@@ -1308,9 +1327,9 @@ impl Default for ServerInfo {
 }
 
 #[allow(clippy::derivable_impls)]
-impl Default for ClientInfo {
+impl Default for InitializeRequestParams {
     fn default() -> Self {
-        ClientInfo {
+        InitializeRequestParams {
             meta: None,
             protocol_version: ProtocolVersion::default(),
             capabilities: ClientCapabilities::default(),

crates/rmcp/src/service/client.rs

@@ -13,13 +13,13 @@ use crate::{
     model::{
         ArgumentInfo, CacheScope, CallToolRequest, CallToolRequestParams, CallToolResponse,
         CallToolResult, CancelTaskParams, CancelTaskRequest, CancelledNotification,
-        CancelledNotificationParam, ClientInfo, ClientJsonRpcMessage, ClientNotification,
-        ClientRequest, ClientResult, CompleteRequest, CompleteRequestParams, CompleteResult,
-        CompletionContext, CompletionInfo, DEFAULT_MRTR_MAX_ROUNDS, DiscoverRequest,
-        DiscoverRequestParams, DiscoverResult, ErrorData, GetExtensions, GetMeta, GetPromptRequest,
+        CancelledNotificationParam, ClientJsonRpcMessage, ClientNotification, ClientRequest,
+        ClientResult, CompleteRequest, CompleteRequestParams, CompleteResult, CompletionContext,
+        CompletionInfo, DEFAULT_MRTR_MAX_ROUNDS, DiscoverRequest, DiscoverRequestParams,
+        DiscoverResult, ErrorData, GetExtensions, GetMeta, GetPromptRequest,
         GetPromptRequestParams, GetPromptResponse, GetPromptResult, GetTaskParams, GetTaskRequest,
-        GetTaskResult, InitializeRequest, InitializedNotification, InputRequest,
-        InputRequiredResult, InputResponses, JsonRpcResponse, ListPromptsRequest,
+        GetTaskResult, InitializeRequest, InitializeRequestParams, InitializedNotification,
+        InputRequest, InputRequiredResult, InputResponses, JsonRpcResponse, ListPromptsRequest,
         ListPromptsResult, ListResourceTemplatesRequest, ListResourceTemplatesResult,
         ListResourcesRequest, ListResourcesResult, ListToolsRequest, ListToolsResult,
         NumberOrString, PaginatedRequestParams, ProgressNotification, ProgressNotificationParam,
@@ -223,7 +223,7 @@ impl ServiceRole for RoleClient {
     type PeerReq = ServerRequest;
     type PeerResp = ServerResult;
     type PeerNot = ServerNotification;
-    type Info = ClientInfo;
+    type Info = InitializeRequestParams;
     type PeerInfo = ServerPeerInfo;
     type InitializeError = ClientInitializeError;
     const IS_CLIENT: bool = true;
@@ -761,7 +761,7 @@ async fn legacy_startup<S, T>(
     transport: &mut T,
     id_provider: &Arc<AtomicU32RequestIdProvider>,
     peer: &Peer<RoleClient>,
-    client_info: ClientInfo,
+    client_info: InitializeRequestParams,
 ) -> Result<(), ClientInitializeError>
 where
     S: Service<RoleClient>,
@@ -817,7 +817,7 @@ async fn discover_startup<S, T>(
     transport: &mut T,
     id_provider: &Arc<AtomicU32RequestIdProvider>,
     peer: &Peer<RoleClient>,
-    client_info: &ClientInfo,
+    client_info: &InitializeRequestParams,
     preferred_versions: Vec<ProtocolVersion>,
 ) -> Result<(), ClientInitializeError>
 where

crates/rmcp/src/service/server.rs

@@ -13,14 +13,15 @@ use super::*;
 use crate::model::{ElicitRequest, ElicitRequestParams, ElicitResult, ElicitationAction};
 use crate::{
     model::{
-        CancelledNotification, CancelledNotificationParam, ClientInfo, ClientJsonRpcMessage,
+        CancelledNotification, CancelledNotificationParam, ClientJsonRpcMessage,
         ClientNotification, ClientRequest, ClientResult, CreateMessageRequest,
-        CreateMessageRequestParams, CreateMessageResult, EmptyResult, ErrorData, ListRootsRequest,
-        ListRootsResult, LoggingMessageNotification, LoggingMessageNotificationParam,
-        ProgressNotification, ProgressNotificationParam, PromptListChangedNotification,
-        ProtocolVersion, ResourceListChangedNotification, ResourceUpdatedNotification,
-        ResourceUpdatedNotificationParam, ServerInfo, ServerNotification, ServerRequest,
-        ServerResult, SubscriptionFilter, SubscriptionsAcknowledgedNotification,
+        CreateMessageRequestParams, CreateMessageResult, EmptyResult, ErrorData,
+        InitializeRequestParams, InitializeResult, ListRootsRequest, ListRootsResult,
+        LoggingMessageNotification, LoggingMessageNotificationParam, ProgressNotification,
+        ProgressNotificationParam, PromptListChangedNotification, ProtocolVersion,
+        ResourceListChangedNotification, ResourceUpdatedNotification,
+        ResourceUpdatedNotificationParam, ServerNotification, ServerRequest, ServerResult,
+        SubscriptionFilter, SubscriptionsAcknowledgedNotification,
         SubscriptionsAcknowledgedNotificationParams, ToolListChangedNotification,
     },
     transport::DynamicTransportError,
@@ -37,8 +38,8 @@ impl ServiceRole for RoleServer {
     type PeerReq = ClientRequest;
     type PeerResp = ClientResult;
     type PeerNot = ClientNotification;
-    type Info = ServerInfo;
-    type PeerInfo = ClientInfo;
+    type Info = InitializeResult;
+    type PeerInfo = InitializeRequestParams;
 
     type InitializeError = ServerInitializeError;
     const IS_CLIENT: bool = false;

crates/rmcp/src/transport/streamable_http_server/tower.rs

@@ -27,8 +27,8 @@ use crate::{
     model::{
         ClientCapabilities, ClientJsonRpcMessage, ClientNotification, ClientRequest, ErrorCode,
         ErrorData, GetExtensions, GetMeta, Implementation, InitializeRequest,
-        InitializeRequestParams, InitializedNotification, JsonObject, JsonRpcError,
-        ProtocolVersion, RequestId, ServerInfo, ServerJsonRpcMessage, ServerResult,
+        InitializeRequestParams, InitializeResult, InitializedNotification, JsonObject,
+        JsonRpcError, ProtocolVersion, RequestId, ServerJsonRpcMessage, ServerResult,
     },
     serve_server,
     service::{
@@ -340,7 +340,7 @@ impl<S: Service<RoleServer>> Service<RoleServer> for NegotiatingStatelessHttpSer
         self.0.handle_notification(notification, context).await
     }
 
-    fn get_info(&self) -> ServerInfo {
+    fn get_info(&self) -> InitializeResult {
         self.0.get_info()
     }
 
@@ -2075,7 +2075,7 @@ where
         Ok(accepted_response())
     }
 
-    /// Build a `ClientInfo` (peer_info) for a stateless request so that
+    /// Build a `InitializeRequestParams` (peer_info) for a stateless request so that
     /// `context.protocol_version()` returns the correct value inside handlers.
     ///
     /// `serve_directly` skips the MCP handshake and accepts `peer_info = None`,

crates/rmcp/tests/common/calculator.rs

@@ -2,7 +2,7 @@
 use rmcp::{
     ServerHandler,
     handler::server::{router::tool::ToolRouter, wrapper::Parameters},
-    model::{ServerCapabilities, ServerInfo},
+    model::{InitializeResult, ServerCapabilities},
     schemars, tool, tool_router,
 };
 #[derive(Debug, serde::Deserialize, schemars::JsonSchema)]
@@ -52,8 +52,8 @@ impl Calculator {
 }
 
 impl ServerHandler for Calculator {
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(ServerCapabilities::builder().enable_tools().build())
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(ServerCapabilities::builder().enable_tools().build())
             .with_instructions("A simple calculator")
     }
 }

crates/rmcp/tests/common/handlers.rs

@@ -115,8 +115,8 @@ impl TestServer {
 
 impl ServerHandler for TestServer {
     #[allow(deprecated)]
-    fn get_info(&self) -> ServerInfo {
-        ServerInfo::new(ServerCapabilities::builder().enable_logging().build())
+    fn get_info(&self) -> InitializeResult {
+        InitializeResult::new(ServerCapabilities::builder().enable_logging().build())
     }
 
     #[allow(deprecated)]