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

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::{ClientLifecycleMode, ClientServiceExt, InitializeRequestParams, ProtocolVersion};
+use rmcp::{ClientLifecycleMode, ClientServiceExt, ProtocolVersion, model::ClientConfig};
 
 // Start directly with server/discover and include client metadata on every request.
-let client = InitializeRequestParams::default()
+let client = ClientConfig::default()
     .serve_with_lifecycle(
         transport,
         ClientLifecycleMode::Discover {
@@ -113,7 +113,7 @@ let client = InitializeRequestParams::default()
 
 // Or probe the discover lifecycle and fall back when a legacy server reports
 // that server/discover is not implemented or does not respond within 10 seconds.
-let client = InitializeRequestParams::default()
+let client = ClientConfig::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) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_resources()
                 .build(),
@@ -582,8 +582,8 @@ impl MyServer {
 
 #[prompt_handler]
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(ServerCapabilities::builder().enable_prompts().build())
+        ServerConfig::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) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::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) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_completions()
                 .enable_prompts()
@@ -1253,8 +1253,8 @@ use rmcp::{
 };
 
 impl ServerHandler for MyServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_tools()
                 .enable_tool_list_changed()
@@ -1584,7 +1584,7 @@ use rmcp::transport::StreamableHttpClientTransport;
 
 // Defaults are stateless-friendly.
 let transport = StreamableHttpClientTransport::from_uri("http://localhost:8000/mcp");
-let client = InitializeRequestParams::default().serve(transport).await?;
+let client = ClientConfig::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)
@@ -1638,7 +1638,7 @@ 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 = InitializeRequestParams::default().serve(transport).await?;
+let client = ClientConfig::default().serve(transport).await?;
 ```
 
 The client allows up to 16 ordinary http POSTs at once. Configure this with
@@ -1742,10 +1742,10 @@ knows what the other supports. Declare yours with the `ServerCapabilities`
 builder in `get_info()`:
 
 ```rust,ignore
-use rmcp::model::{InitializeResult, ServerCapabilities};
+use rmcp::model::{ServerCapabilities, ServerConfig};
 
-fn get_info(&self) -> InitializeResult {
+fn get_info(&self) -> ServerConfig {
-    InitializeResult::new(
+    ServerConfig::new(
         ServerCapabilities::builder()
             .enable_tools()
             .enable_prompts()

conformance/src/bin/client.rs

@@ -74,8 +74,8 @@ impl ClientHandler for BasicClientHandler {}
 struct ElicitationDefaultsClientHandler;
 
 impl ClientHandler for ElicitationDefaultsClientHandler {
-    fn get_info(&self) -> InitializeRequestParams {
+    fn get_info(&self) -> ClientConfig {
-        let mut info = InitializeRequestParams::default();
+        let mut info = ClientConfig::default();
         info.capabilities.elicitation = Some(
             ElicitationCapability::new()
                 .with_form(FormElicitationCapability::new().with_schema_validation(true)),
@@ -163,8 +163,8 @@ impl ClientHandler for ElicitationDefaultsClientHandler {
 struct FullClientHandler;
 
 impl ClientHandler for FullClientHandler {
-    fn get_info(&self) -> InitializeRequestParams {
+    fn get_info(&self) -> ClientConfig {
-        let mut info = InitializeRequestParams::default();
+        let mut info = ClientConfig::default();
         info.capabilities.elicitation = Some(
             ElicitationCapability::new()
                 .with_form(FormElicitationCapability::new().with_schema_validation(true)),

conformance/src/bin/server.rs

@@ -704,8 +704,8 @@ impl ServerHandler for ConformanceServer {
         (name == "test_custom_header").then(custom_header_tool)
     }
 
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_prompts()
                 .enable_prompts_list_changed()

crates/rmcp-macros/src/lib.rs

@@ -217,8 +217,8 @@ pub fn tool_router(attr: TokenStream, input: TokenStream) -> TokenStream {
 /// ```rust,ignore
 /// #[tool_handler]
 /// impl ServerHandler for MyToolHandler {
-///     fn get_info(&self) -> InitializeResult {
+///     fn get_info(&self) -> ServerConfig {
-///         InitializeResult::new(ServerCapabilities::builder().enable_tools().build())
+///         ServerConfig::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 `InitializeResult` with the appropriate capabilities.
+/// Build a `get_info()` method that returns `ServerConfig` 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::InitializeResult {
+        fn get_info(&self) -> rmcp::model::ServerConfig {
-            rmcp::model::InitializeResult::new(
+            rmcp::model::ServerConfig::new(
                 rmcp::model::ServerCapabilities::builder()
                     #(#capability_calls)*
                     .build()

crates/rmcp/src/handler/client.rs

@@ -274,8 +274,8 @@ macro_rules! client_handler_methods {
             std::future::ready(())
         }
 
-        fn get_info(&self) -> ClientInfo {
+        fn get_info(&self) -> ClientConfig {
-            InitializeRequestParams::default()
+            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.
+/// Do nothing, with a specific client config.
-impl ClientHandler for ClientInfo {
+impl ClientHandler for ClientConfig {
-    fn get_info(&self) -> ClientInfo {
+    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 {
+        ///     fn get_info(&self) -> ServerConfig {
-        ///         ServerInfo::default()
+        ///         ServerConfig::default()
         ///     }
         ///
         ///     async fn initialize(
@@ -600,8 +600,8 @@ macro_rules! server_handler_methods {
             std::future::ready(())
         }
 
-        fn get_info(&self) -> ServerInfo {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::default()
+            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
+/// This is what `ServerHandler::get_info` returns. It is an alias for
-/// `serverInfo` field, which is only the [`Implementation`] identity (#1082).
+/// [`InitializeResult`] because the same value is sent as the `initialize`
-//
+/// response on the wire.
-// The signatures this crate publishes (`ServerHandler::get_info`,
+///
-// `DiscoverResult::from_server_info`, and the `ClientInfo` equivalents below)
+/// # Examples
-// 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
+/// use rmcp::model::{ServerCapabilities, ServerConfig};
-// signatures onto the canonical names is a documented API change and belongs in
+///
-// the next major release.
+/// let config = ServerConfig::new(ServerCapabilities::builder().enable_tools().build())
-#[deprecated(note = "use `InitializeResult` instead")]
+///     .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
+/// The name collides with the protocol's `clientInfo` field, which is only the
-/// `clientInfo` field, which is only the [`Implementation`] identity (#1082).
+/// [`Implementation`] identity, so `client_info.client_info` was easy to
-#[deprecated(note = "use `InitializeRequestParams` instead")]
+/// 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,
+        CancelledNotificationParam, ClientConfig, ClientJsonRpcMessage, ClientNotification,
-        ClientResult, CompleteRequest, CompleteRequestParams, CompleteResult, CompletionContext,
+        ClientRequest, ClientResult, CompleteRequest, CompleteRequestParams, CompleteResult,
-        CompletionInfo, DEFAULT_MRTR_MAX_ROUNDS, DiscoverRequest, DiscoverRequestParams,
+        CompletionContext, CompletionInfo, DEFAULT_MRTR_MAX_ROUNDS, DiscoverRequest,
-        DiscoverResult, ErrorData, GetExtensions, GetMeta, GetPromptRequest,
+        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,
+        InitializeRequestParams, ListRootsRequest, ListRootsResult, LoggingMessageNotification,
-        LoggingMessageNotification, LoggingMessageNotificationParam, ProgressNotification,
+        LoggingMessageNotificationParam, ProgressNotification, ProgressNotificationParam,
-        ProgressNotificationParam, PromptListChangedNotification, ProtocolVersion,
+        PromptListChangedNotification, ProtocolVersion, ResourceListChangedNotification,
-        ResourceListChangedNotification, ResourceUpdatedNotification,
+        ResourceUpdatedNotification, ResourceUpdatedNotificationParam, ServerConfig,
-        ResourceUpdatedNotificationParam, ServerNotification, ServerRequest, ServerResult,
+        ServerNotification, ServerRequest, ServerResult, SubscriptionFilter,
-        SubscriptionFilter, SubscriptionsAcknowledgedNotification,
+        SubscriptionsAcknowledgedNotification, SubscriptionsAcknowledgedNotificationParams,
-        SubscriptionsAcknowledgedNotificationParams, ToolListChangedNotification,
+        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,
+        InitializeRequestParams, InitializedNotification, JsonObject, JsonRpcError,
-        JsonRpcError, ProtocolVersion, RequestId, ServerJsonRpcMessage, ServerResult,
+        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()
     }
 

crates/rmcp/tests/common/calculator.rs

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

crates/rmcp/tests/test_cancelled_response.rs

@@ -8,8 +8,8 @@ use std::{collections::BTreeSet, process::Stdio, time::Duration};
 use rmcp::{
     ErrorData as McpError, RoleServer, ServerHandler, ServiceExt,
     model::{
-        CallToolRequestParams, CallToolResponse, CallToolResult, ContentBlock, InitializeResult,
+        CallToolRequestParams, CallToolResponse, CallToolResult, ContentBlock, ServerCapabilities,
-        ServerCapabilities,
+        ServerConfig,
     },
     service::RequestContext,
 };
@@ -91,8 +91,8 @@ async fn cancelled_request_receives_no_response() -> anyhow::Result<()> {
 struct WaitForCancelServer;
 
 impl ServerHandler for WaitForCancelServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(ServerCapabilities::builder().enable_tools().build())
+        ServerConfig::new(ServerCapabilities::builder().enable_tools().build())
     }
 
     async fn call_tool(

crates/rmcp/tests/test_custom_headers.rs

@@ -719,7 +719,7 @@ async fn test_server_rejects_unsupported_protocol_version() {
     use http_body_util::Full;
     use rmcp::{
         handler::server::ServerHandler,
-        model::{InitializeResult, ServerCapabilities},
+        model::{ServerCapabilities, ServerConfig},
         transport::streamable_http_server::{
             StreamableHttpServerConfig, StreamableHttpService, session::local::LocalSessionManager,
         },
@@ -730,8 +730,8 @@ async fn test_server_rejects_unsupported_protocol_version() {
     struct TestHandler;
 
     impl ServerHandler for TestHandler {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::new(ServerCapabilities::builder().build())
+            ServerConfig::new(ServerCapabilities::builder().build())
         }
     }
 
@@ -892,7 +892,7 @@ async fn test_server_validates_host_when_origin_validation_is_disabled_by_defaul
     use http_body_util::Full;
     use rmcp::{
         handler::server::ServerHandler,
-        model::{InitializeResult, ServerCapabilities},
+        model::{ServerCapabilities, ServerConfig},
         transport::streamable_http_server::{
             StreamableHttpServerConfig, StreamableHttpService, session::local::LocalSessionManager,
         },
@@ -903,8 +903,8 @@ async fn test_server_validates_host_when_origin_validation_is_disabled_by_defaul
     struct TestHandler;
 
     impl ServerHandler for TestHandler {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::new(ServerCapabilities::builder().build())
+            ServerConfig::new(ServerCapabilities::builder().build())
         }
     }
 
@@ -975,7 +975,7 @@ async fn test_server_validates_host_header_port_for_dns_rebinding_protection() {
     use http_body_util::Full;
     use rmcp::{
         handler::server::ServerHandler,
-        model::{InitializeResult, ServerCapabilities},
+        model::{ServerCapabilities, ServerConfig},
         transport::streamable_http_server::{
             StreamableHttpServerConfig, StreamableHttpService, session::local::LocalSessionManager,
         },
@@ -986,8 +986,8 @@ async fn test_server_validates_host_header_port_for_dns_rebinding_protection() {
     struct TestHandler;
 
     impl ServerHandler for TestHandler {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::new(ServerCapabilities::builder().build())
+            ServerConfig::new(ServerCapabilities::builder().build())
         }
     }
 
@@ -1046,7 +1046,7 @@ async fn test_server_falls_back_to_uri_authority_when_host_header_missing() {
     use http_body_util::Full;
     use rmcp::{
         handler::server::ServerHandler,
-        model::{InitializeResult, ServerCapabilities},
+        model::{ServerCapabilities, ServerConfig},
         transport::streamable_http_server::{
             StreamableHttpServerConfig, StreamableHttpService, session::local::LocalSessionManager,
         },
@@ -1057,8 +1057,8 @@ async fn test_server_falls_back_to_uri_authority_when_host_header_missing() {
     struct TestHandler;
 
     impl ServerHandler for TestHandler {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::new(ServerCapabilities::builder().build())
+            ServerConfig::new(ServerCapabilities::builder().build())
         }
     }
 
@@ -1132,7 +1132,7 @@ mod origin_validation {
     use http_body_util::Full;
     use rmcp::{
         handler::server::ServerHandler,
-        model::{InitializeResult, ServerCapabilities},
+        model::{ServerCapabilities, ServerConfig},
         transport::streamable_http_server::{
             StreamableHttpServerConfig, StreamableHttpService, session::local::LocalSessionManager,
         },
@@ -1143,8 +1143,8 @@ mod origin_validation {
     struct TestHandler;
 
     impl ServerHandler for TestHandler {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            InitializeResult::new(ServerCapabilities::builder().build())
+            ServerConfig::new(ServerCapabilities::builder().build())
         }
     }
 

crates/rmcp/tests/test_discover_http_client_startup.rs

@@ -16,7 +16,7 @@ use axum::{
 };
 use rmcp::{
     ClientLifecycleMode, ClientServiceExt, ServerHandler,
-    model::{DiscoverResult, ErrorCode, ErrorData, InitializeRequestParams, ProtocolVersion},
+    model::{ClientConfig, DiscoverResult, ErrorCode, ErrorData, ProtocolVersion},
     service::{MaybeSendFuture, RequestContext, RoleServer},
     transport::{
         StreamableHttpClientTransport,
@@ -132,7 +132,7 @@ async fn discover_http_client_bootstraps_headers_without_initialize() {
     let transport = StreamableHttpClientTransport::from_config(
         StreamableHttpClientTransportConfig::with_uri(format!("http://{address}/mcp")),
     );
-    let client = InitializeRequestParams::default()
+    let client = ClientConfig::default()
         .serve_with_lifecycle(
             transport,
             ClientLifecycleMode::Discover {
@@ -176,7 +176,7 @@ async fn auto_http_client_falls_back_to_stateful_legacy_startup() {
     let transport = StreamableHttpClientTransport::from_config(
         StreamableHttpClientTransportConfig::with_uri(format!("http://{address}/mcp")),
     );
-    let client = InitializeRequestParams::default()
+    let client = ClientConfig::default()
         .serve_with_lifecycle(
             transport,
             ClientLifecycleMode::Auto {
@@ -217,7 +217,7 @@ async fn auto_http_client_falls_back_after_plain_text_4xx_rejection() {
     let transport = StreamableHttpClientTransport::from_config(
         StreamableHttpClientTransportConfig::with_uri(format!("http://{address}/mcp")),
     );
-    let client = InitializeRequestParams::default()
+    let client = ClientConfig::default()
         .serve_with_lifecycle(
             transport,
             ClientLifecycleMode::Auto {

crates/rmcp/tests/test_handler_cache_hints.rs

@@ -5,7 +5,7 @@ use rmcp::{
     ClientHandler, RoleClient, RoleServer, ServerHandler,
     handler::server::router::{prompt::PromptRouter, tool::ToolRouter},
     model::{
-        CacheScope, InitializeRequestParams, InitializeResult, ListPromptsResult, ListToolsResult,
+        CacheScope, ClientConfig, InitializeResult, ListPromptsResult, ListToolsResult,
         ProtocolVersion,
     },
     prompt_handler,
@@ -38,8 +38,8 @@ struct VersionedClient {
 }
 
 impl ClientHandler for VersionedClient {
-    fn get_info(&self) -> InitializeRequestParams {
+    fn get_info(&self) -> ClientConfig {
-        let mut info = InitializeRequestParams::default();
+        let mut info = ClientConfig::default();
         info.protocol_version = self.protocol_version.clone();
         info
     }

crates/rmcp/tests/test_inflight_response_drain.rs

@@ -14,7 +14,7 @@ use std::{
 use rmcp::{
     ServerHandler, ServiceExt,
     handler::server::{router::tool::ToolRouter, wrapper::Parameters},
-    model::{CallToolRequestParams, InitializeRequestParams, InitializeResult, ServerCapabilities},
+    model::{CallToolRequestParams, ClientConfig, ServerCapabilities, ServerConfig},
     service::QuitReason,
     tool, tool_handler, tool_router,
 };
@@ -55,8 +55,8 @@ impl SlowToolServer {
 
 #[tool_handler]
 impl ServerHandler for SlowToolServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(ServerCapabilities::builder().enable_tools().build())
+        ServerConfig::new(ServerCapabilities::builder().enable_tools().build())
     }
 }
 
@@ -64,8 +64,8 @@ impl ServerHandler for SlowToolServer {
 struct DummyClientHandler;
 
 impl rmcp::ClientHandler for DummyClientHandler {
-    fn get_info(&self) -> InitializeRequestParams {
+    fn get_info(&self) -> ClientConfig {
-        InitializeRequestParams::default()
+        ClientConfig::default()
     }
 }
 

crates/rmcp/tests/test_mrtr_behavior.rs

@@ -114,8 +114,8 @@ impl MacroMrtrServer {
 
 #[tool_handler]
 impl ServerHandler for MacroMrtrServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        let mut info = InitializeResult::new(ServerCapabilities::builder().enable_tools().build());
+        let mut info = ServerConfig::new(ServerCapabilities::builder().enable_tools().build());
         info.protocol_version = ProtocolVersion::V_2026_07_28;
         info
     }
@@ -221,8 +221,8 @@ impl MrtrServer {
 }
 
 impl ServerHandler for MrtrServer {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        let mut info = InitializeResult::new(
+        let mut info = ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_tools()
                 .enable_prompts()
@@ -609,9 +609,8 @@ async fn request_state_codec_seals_and_verifies_through_the_loop() -> anyhow::Re
     struct SealingServer;
 
     impl ServerHandler for SealingServer {
-        fn get_info(&self) -> InitializeResult {
+        fn get_info(&self) -> ServerConfig {
-            let mut info =
+            let mut info = ServerConfig::new(ServerCapabilities::builder().enable_tools().build());
-                InitializeResult::new(ServerCapabilities::builder().enable_tools().build());
             info.protocol_version = ProtocolVersion::V_2026_07_28;
             info
         }

crates/rmcp/tests/test_notification.rs

@@ -5,8 +5,8 @@ use std::sync::Arc;
 use rmcp::{
     ClientHandler, ServerHandler, ServiceExt,
     model::{
-        ClientNotification, CustomNotification, InitializeResult, ResourceUpdatedNotificationParam,
+        ClientNotification, CustomNotification, ResourceUpdatedNotificationParam,
-        ServerCapabilities, ServerNotification, SubscribeRequestParams,
+        ServerCapabilities, ServerConfig, ServerNotification, SubscribeRequestParams,
     },
 };
 use serde_json::json;
@@ -16,8 +16,8 @@ use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 struct Server {}
 
 impl ServerHandler for Server {
-    fn get_info(&self) -> InitializeResult {
+    fn get_info(&self) -> ServerConfig {
-        InitializeResult::new(
+        ServerConfig::new(
             ServerCapabilities::builder()
                 .enable_resources()
                 .enable_resources_subscribe()