mcpkit-server

Server implementation for the Model Context Protocol (MCP).

This crate provides the server-side implementation including composable handler traits, a fluent builder API, and request routing.

Overview

Building an MCP server involves:

Implementing the ServerHandler trait (required)
Implementing optional capability traits (ToolHandler, ResourceHandler, etc.)
Using ServerBuilder to create a configured server
Running the server with a transport

Usage

use mcpkit_server::{ServerBuilder, ServerHandler};
use mcpkit_core::capability::{ServerInfo, ServerCapabilities};

struct MyServer;

impl ServerHandler for MyServer {
    fn server_info(&self) -> ServerInfo {
        ServerInfo::new("my-server", "1.0.0")
    }

    fn capabilities(&self) -> ServerCapabilities {
        ServerCapabilities::new().with_tools()
    }
}

let server = ServerBuilder::new(MyServer).build();

Handler Traits

The server uses composable handler traits:

Trait	Purpose
`ServerHandler`	Core trait required for all servers
`ToolHandler`	Handle tool discovery and execution
`ResourceHandler`	Handle resource discovery and reading
`PromptHandler`	Handle prompt discovery and rendering
`TaskHandler`	Handle long-running task operations
`SamplingHandler`	Handle server-initiated LLM requests
`ElicitationHandler`	Handle structured user input requests
`CompletionHandler`	Handle argument completion requests
`LoggingHandler`	Handle log level changes

Context

Handlers receive a Context that provides:

Request metadata (ID, progress token)
Client and server capabilities
Protocol version for feature detection
Cancellation checking
Progress reporting
Notification sending

Metrics

Built-in request metrics collection via ServerMetrics:

Request counts by method
Success/error rates
Duration tracking

Part of mcpkit

This crate is part of the mcpkit SDK. For most use cases, depend on mcpkit directly rather than this crate.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.

mcpkit-server 0.2.2