Trait ServerHandler 

pub trait ServerHandler: Send + Sync {
    // Required method
    fn server_info(&self) -> ServerInfo;

    // Provided methods
    fn capabilities(&self) -> ServerCapabilities { ... }
    fn instructions(&self) -> Option<String> { ... }
    fn on_initialized(
        &self,
        _ctx: &Context<'_>,
    ) -> impl Future<Output = ()> + Send { ... }
    fn on_shutdown(&self) -> impl Future<Output = ()> + Send { ... }
}

Core server handler trait - required for all MCP servers.

This trait defines the minimal requirements for an MCP server. All servers must implement this trait. Additional capabilities are added by implementing optional handler traits.

Note: Context uses lifetime references (no 'static requirement).

Required Methods

fn server_info(&self) -> ServerInfo

Return information about this server.

This is called during the initialization handshake.

Provided Methods

fn capabilities(&self) -> ServerCapabilities

Return the capabilities of this server.

The default implementation returns empty capabilities. Override this to advertise specific capabilities.

fn instructions(&self) -> Option<String>

Return optional instructions for using this server.

These instructions are sent to the client during initialization and can help the AI assistant understand how to use this server.

fn on_initialized(&self, _ctx: &Context<'_>) -> impl Future<Output = ()> + Send

Called after initialization is complete.

This is a good place to set up any state that requires the connection to be established.

fn on_shutdown(&self) -> impl Future<Output = ()> + Send

Called when the connection is about to be closed.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T: ServerHandler> ServerHandler for Arc<T>

fn server_info(&self) -> ServerInfo

fn capabilities(&self) -> ServerCapabilities

fn instructions(&self) -> Option<String>

fn on_initialized(&self, ctx: &Context<'_>) -> impl Future<Output = ()> + Send

fn on_shutdown(&self) -> impl Future<Output = ()> + Send

Implementors