Struct McpServer 

pub struct McpServer<S>
where
    S: Send + Sync + ?Sized,
{ /* private fields */ }

MCP server that dispatches JSON-RPC requests to the appropriate handler

Generic over S — the project-specific server state type, shared as Arc<S>. S is ?Sized, so a host may parameterize it with a resource façade trait object (dyn HostRuntime); a host needing interior mutability parameterizes S with it (e.g. RwLock<Inner>). Owns the shared state and tool registry. Transport layers feed parsed requests into handle_request and send the returned responses.

Implementations

impl<S> McpServer<S>

where S: Send + Sync + 'static + ?Sized,

pub fn new( name: impl Into<String>, version: impl Into<String>, tools: ToolRegistry<S>, state: Arc<S>, ) -> McpServer<S>

Create a server with the given name, version, tool registry, and shared state

Defaults to advertising tool support only, no instructions, and the modern + current legacy protocol revisions. Use the with_* builders to override the advertised capabilities, instructions, or supported versions.

pub fn with_capabilities(self, capabilities: ServerCapabilities) -> McpServer<S>

Override the capabilities advertised in initialize and server/discover.

pub fn with_instructions(self, instructions: impl Into<String>) -> McpServer<S>

Set the natural-language instructions advertised to clients.

pub fn with_supported_versions(self, versions: Vec<String>) -> McpServer<S>

Override the protocol revisions the server advertises and accepts, in preference order.

pub fn with_auth_hook(self, auth_hook: Arc<dyn AuthHook<S>>) -> McpServer<S>

Install a host authentication hook for the HTTP transport. With a hook, the transport authenticates every request (rejecting with 401/403); with none, every request runs as the default anonymous context.

pub fn with_allowed_origins(self, origins: Vec<String>) -> McpServer<S>

Restrict the Origins the HTTP transport accepts. An empty list (the default) or one containing "*" allows any origin; a request whose Origin header is present and not listed is rejected with 403.

pub fn allowed_origins(&self) -> &[String]

The Origin allowlist the HTTP transport enforces.

pub fn with_tool_dispatcher( self, dispatcher: Arc<dyn ToolDispatcher<S>>, ) -> McpServer<S>

Install a host ToolDispatcher that owns tools/list and tools/call (per-caller views, quota, execution, usage). When installed it replaces the built-in registry for both tool methods.

pub fn with_method_handler( self, handler: Arc<dyn MethodHandler<S>>, ) -> McpServer<S>

Install a host MethodHandler for methods the engine doesn’t natively serve (resources/*, prompts/*, sampling/*, …). Unknown methods are offered to it before falling through to method-not-found.

pub async fn authenticate( &self, request: &JsonRpcRequest, ) -> Result<ToolContext, AuthError>

Authenticate a request via the configured AuthHook, or yield the default anonymous ToolContext when no hook is installed.

Errors

Returns the hook’s AuthError (401/403) when authentication fails.

pub async fn handle_raw(&self, raw: &str) -> Option<JsonRpcResponse>

Route a raw JSON string to the appropriate MCP handler

Parses the string as a JsonRpcRequest, dispatches it, and returns the serialized response. Returns None for notifications.

pub async fn handle_request( &self, request: JsonRpcRequest, ) -> Option<JsonRpcResponse>

Route a parsed JSON-RPC request under the default anonymous context.

Convenience for transports without authentication (e.g. stdio). See Self::handle_request_with_context for the authenticated path.

pub async fn handle_request_with_context( &self, request: JsonRpcRequest, ctx: &ToolContext, ) -> Option<JsonRpcResponse>

Route a parsed JSON-RPC request, dispatching tool calls under the given per-call ToolContext (resolved by the transport’s auth hook).

Performs era detection on each request: one carrying modern per-request _meta (revision 2026-07-28) is served statelessly via Self::process_modern; otherwise it follows the legacy initialize/session path. Returns None for notifications (no id).