feat(model): add ServerConfig and ClientConfig (#1266)

crates/rmcp/src/handler/client.rs

@@ -274,8 +274,8 @@ macro_rules! client_handler_methods {
             std::future::ready(())
         }
 
-        fn get_info(&self) -> ClientInfo {
-            InitializeRequestParams::default()
+        fn get_info(&self) -> ClientConfig {
+            ClientConfig::default()
         }
     };
 }
@@ -292,12 +292,12 @@ pub trait ClientHandler: Sized + 'static {
     client_handler_methods!();
 }
 
-/// Do nothing, with default client info.
+/// Do nothing, with the default client config.
 impl ClientHandler for () {}
 
-/// Do nothing, with a specific client info.
-impl ClientHandler for ClientInfo {
-    fn get_info(&self) -> ClientInfo {
+/// Do nothing, with a specific client config.
+impl ClientHandler for ClientConfig {
+    fn get_info(&self) -> ClientConfig {
         self.clone()
     }
 }
@@ -422,7 +422,7 @@ macro_rules! impl_client_handler_for_wrapper {
                 (**self).on_custom_notification(notification, context)
             }
 
-            fn get_info(&self) -> ClientInfo {
+            fn get_info(&self) -> ClientConfig {
                 (**self).get_info()
             }
         }

crates/rmcp/src/handler/server.rs

@@ -334,15 +334,15 @@ macro_rules! server_handler_methods {
         /// ```
         /// use rmcp::{
         ///     ErrorData as McpError, RoleServer, ServerHandler,
-        ///     model::{InitializeRequestParams, InitializeResult, ServerInfo},
+        ///     model::{InitializeRequestParams, InitializeResult, ServerConfig},
         ///     service::RequestContext,
         /// };
         ///
         /// struct MyServer;
         ///
         /// impl ServerHandler for MyServer {
-        ///     fn get_info(&self) -> ServerInfo {
-        ///         ServerInfo::default()
+        ///     fn get_info(&self) -> ServerConfig {
+        ///         ServerConfig::default()
         ///     }
         ///
         ///     async fn initialize(
@@ -600,8 +600,8 @@ macro_rules! server_handler_methods {
             std::future::ready(())
         }
 
-        fn get_info(&self) -> ServerInfo {
-            InitializeResult::default()
+        fn get_info(&self) -> ServerConfig {
+            ServerConfig::default()
         }
 
         /// SEP-2663 `tasks/get`: return the current [`DetailedTask`] state.
@@ -839,7 +839,7 @@ macro_rules! impl_server_handler_for_wrapper {
                 (**self).on_custom_notification(notification, context)
             }
 
-            fn get_info(&self) -> ServerInfo {
+            fn get_info(&self) -> ServerConfig {
                 (**self).get_info()
             }
 

crates/rmcp/src/model.rs

@@ -1119,26 +1119,58 @@ impl InitializeResult {
     }
 }
 
-/// Full server initialize payload (`InitializeResult`).
+/// A server's own configuration: the protocol version, capabilities,
+/// implementation identity, and instructions it advertises to clients.
 ///
-/// 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")]
+/// This is what `ServerHandler::get_info` returns. It is an alias for
+/// [`InitializeResult`] because the same value is sent as the `initialize`
+/// response on the wire.
+///
+/// # Examples
+///
+/// ```
+/// use rmcp::model::{ServerCapabilities, ServerConfig};
+///
+/// let config = ServerConfig::new(ServerCapabilities::builder().enable_tools().build())
+///     .with_instructions("Call `add` to sum two numbers.");
+/// assert!(config.capabilities.tools.is_some());
+/// ```
+pub type ServerConfig = InitializeResult;
+
+/// A client's own configuration: the protocol version, capabilities, and
+/// implementation identity it advertises to servers.
+///
+/// This is what `ClientHandler::get_info` returns. It is an alias for
+/// [`InitializeRequestParams`] because the same value is sent as the
+/// `initialize` request on the wire.
+///
+/// # Examples
+///
+/// ```
+/// use rmcp::model::{ClientCapabilities, ClientConfig, Implementation};
+///
+/// let config = ClientConfig::new(
+///     ClientCapabilities::builder().enable_elicitation().build(),
+///     Implementation::new("my-client", "1.0.0"),
+/// );
+/// assert!(config.capabilities.elicitation.is_some());
+/// ```
+pub type ClientConfig = InitializeRequestParams;
+
+/// Deprecated alias for [`ServerConfig`].
+///
+/// The name collides with the protocol's `serverInfo` field, which is only the
+/// [`Implementation`] identity, so `server_info.server_info` was easy to
+/// misread (#1082).
+#[deprecated(note = "use `ServerConfig` instead")]
 pub type ServerInfo = InitializeResult;
 
-/// Full client initialize params (`InitializeRequestParams`).
+/// Deprecated alias for [`ClientConfig`].
 ///
-/// Prefer [`InitializeRequestParams`]. The name collides with the protocol's
-/// `clientInfo` field, which is only the [`Implementation`] identity (#1082).
-#[deprecated(note = "use `InitializeRequestParams` instead")]
+/// The name collides with the protocol's `clientInfo` field, which is only the
+/// [`Implementation`] identity, so `client_info.client_info` was easy to
+/// misread (#1082).
+#[deprecated(note = "use `ClientConfig` instead")]
 pub type ClientInfo = InitializeRequestParams;
 
 /// Information negotiated about a server peer.
@@ -1298,18 +1330,18 @@ impl DiscoverResult {
         self
     }
 
-    /// Create a discovery result from the server's initialization information.
+    /// Create a discovery result from the server's configuration.
     pub fn from_server_info(
         supported_versions: Vec<ProtocolVersion>,
-        server_info: ServerInfo,
+        server_config: ServerConfig,
     ) -> Self {
-        let InitializeResult {
+        let ServerConfig {
             capabilities,
             server_info,
             instructions,
             meta,
             ..
-        } = server_info;
+        } = server_config;
         let mut result = Self {
             result_type: ResultType::COMPLETE,
             supported_versions,

crates/rmcp/src/service/client.rs

@@ -13,10 +13,10 @@ use crate::{
     model::{
         ArgumentInfo, CacheScope, CallToolRequest, CallToolRequestParams, CallToolResponse,
         CallToolResult, CancelTaskParams, CancelTaskRequest, CancelledNotification,
-        CancelledNotificationParam, ClientJsonRpcMessage, ClientNotification, ClientRequest,
-        ClientResult, CompleteRequest, CompleteRequestParams, CompleteResult, CompletionContext,
-        CompletionInfo, DEFAULT_MRTR_MAX_ROUNDS, DiscoverRequest, DiscoverRequestParams,
-        DiscoverResult, ErrorData, GetExtensions, GetMeta, GetPromptRequest,
+        CancelledNotificationParam, ClientConfig, 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, InitializeRequestParams, InitializedNotification,
         InputRequest, InputRequiredResult, InputResponses, JsonRpcResponse, ListPromptsRequest,
@@ -266,7 +266,7 @@ impl ServiceRole for RoleClient {
     type PeerReq = ServerRequest;
     type PeerResp = ServerResult;
     type PeerNot = ServerNotification;
-    type Info = InitializeRequestParams;
+    type Info = ClientConfig;
     type PeerInfo = ServerPeerInfo;
     type InitializeError = ClientInitializeError;
     const IS_CLIENT: bool = true;

crates/rmcp/src/service/server.rs

@@ -16,13 +16,13 @@ use crate::{
         CancelledNotification, CancelledNotificationParam, ClientJsonRpcMessage,
         ClientNotification, ClientRequest, ClientResult, CreateMessageRequest,
         CreateMessageRequestParams, CreateMessageResult, EmptyResult, ErrorData,
-        InitializeRequestParams, InitializeResult, ListRootsRequest, ListRootsResult,
-        LoggingMessageNotification, LoggingMessageNotificationParam, ProgressNotification,
-        ProgressNotificationParam, PromptListChangedNotification, ProtocolVersion,
-        ResourceListChangedNotification, ResourceUpdatedNotification,
-        ResourceUpdatedNotificationParam, ServerNotification, ServerRequest, ServerResult,
-        SubscriptionFilter, SubscriptionsAcknowledgedNotification,
-        SubscriptionsAcknowledgedNotificationParams, ToolListChangedNotification,
+        InitializeRequestParams, ListRootsRequest, ListRootsResult, LoggingMessageNotification,
+        LoggingMessageNotificationParam, ProgressNotification, ProgressNotificationParam,
+        PromptListChangedNotification, ProtocolVersion, ResourceListChangedNotification,
+        ResourceUpdatedNotification, ResourceUpdatedNotificationParam, ServerConfig,
+        ServerNotification, ServerRequest, ServerResult, SubscriptionFilter,
+        SubscriptionsAcknowledgedNotification, SubscriptionsAcknowledgedNotificationParams,
+        ToolListChangedNotification,
     },
     transport::DynamicTransportError,
 };
@@ -38,7 +38,7 @@ impl ServiceRole for RoleServer {
     type PeerReq = ClientRequest;
     type PeerResp = ClientResult;
     type PeerNot = ClientNotification;
-    type Info = InitializeResult;
+    type Info = ServerConfig;
     type PeerInfo = InitializeRequestParams;
 
     type InitializeError = ServerInitializeError;

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, InitializeResult, InitializedNotification, JsonObject,
-        JsonRpcError, ProtocolVersion, RequestId, ServerJsonRpcMessage, ServerResult,
+        InitializeRequestParams, InitializedNotification, JsonObject, JsonRpcError,
+        ProtocolVersion, RequestId, ServerConfig, ServerJsonRpcMessage, ServerResult,
     },
     serve_server,
     service::{
@@ -367,7 +367,7 @@ impl<S: Service<RoleServer>> Service<RoleServer> for NegotiatingStatelessHttpSer
         self.0.handle_notification(notification, context).await
     }
 
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
         self.0.get_info()
     }