Struct Server 

pub struct Server { /* private fields */ }

A built MCP server. Cheap to clone; all clones share one registry.

Server implements tower_service::Service<McpRequest>, so tower middleware (timeouts, rate limits, tracing) can wrap it.

Implementations

impl Server

pub fn legacy_clients_enabled(&self) -> bool

Whether legacy (2025-11-25, 2025-06-18) clients are served.

impl Server

pub fn builder( name: impl Into<String>, version: impl Into<String>, ) -> ServerBuilder

Starts building a server.

pub fn limits(&self) -> &Limits

The configured limits.

pub fn mirrored_params(&self, tool: &str) -> Option<&[MirroredParam]>

Parameters of tool mirrored into Mcp-Param-* HTTP headers, or None if the tool does not exist.

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

The protocol versions this server accepts.

pub async fn handle_bytes( &self, bytes: &[u8], transport: TransportContext, cancellation: CancellationToken, ) -> Option<Response>

Parses raw bytes and handles the message. Returns the response to send, or None for notifications, cancelled requests and stray responses.

pub async fn handle(&self, request: McpRequest) -> Option<Response>

Handles a parsed message.

impl Server

pub async fn serve_http( self, addr: impl ToSocketAddrs + Clone + Debug, ) -> Result<()>

Serves Streamable HTTP at path /mcp with the default security settings (localhost origins and hosts only) until the process stops.

Bind to a loopback address (e.g. 127.0.0.1:8000) unless the server is meant to be reachable from other machines.

Errors

Returns an error when the address cannot be bound.

impl Server

pub async fn serve_stdio(self) -> Result<()>

Serves requests over the process’s stdin and stdout until stdin is closed.

When stdin is an interactive terminal (someone ran the server by hand), a short explanation is printed on stderr: an MCP server waits silently for JSON-RPC messages, which looks like a hang.

Errors

Returns an error when reading stdin or writing stdout fails.

Trait Implementations

impl Clone for Server

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Server

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Service<McpRequest> for Server

type Response = Option<Response>

Responses given by the service.

type Error = !

Errors produced by the service.

type Future = Pin<Box<dyn Future<Output = Result<<Server as Service<McpRequest>>::Response, !>> + Send>>

The future response value.

fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests.

fn call(&mut self, request: McpRequest) -> Self::Future

Process the request and return the response asynchronously.