Crate model_context_protocol 

MCP - Model Context Protocol

A Rust implementation of the Model Context Protocol (MCP) for AI tool integration.

This crate provides the infrastructure for communicating with MCP servers via stdio/HTTP transports.

Features

• McpHub: Central hub for managing multiple MCP server connections
• Multiple Transports: Support for stdio and HTTP-based MCP servers
• Tool Routing: Automatic routing of tool calls to the correct server
• Macros: #[mcp_tool] for easy tool definitions from functions

Quick Start - Creating a Server

use mcp::macros::mcp_tool;
use mcp::{McpServerConfig, McpServer};

// Define tools as simple functions
#[mcp_tool(description = "Add two numbers")]
fn add(a: f64, b: f64) -> f64 { a + b }

#[mcp_tool(description = "Subtract two numbers")]
fn subtract(a: f64, b: f64) -> f64 { a - b }

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config = McpServerConfig::builder()
        .name("calculator")
        .version("1.0.0")
        .with_stdio_transport()
        .with_tools(tools![AddTool, SubtractTool])
        .build();

    McpServer::run(config).await?;
    Ok(())
}

Connecting to Servers

use mcp::{McpHub, McpServerConnectionConfig};

let hub = McpHub::new();

// Connect to an external server
let config = McpServerConnectionConfig::stdio("my-server", "node", vec!["server.js".into()]);
hub.connect(config).await?;

// List available tools
let tools = hub.list_all_tools().await?;

Feature Flags

• default - Enables stdio, http, and macros features
• stdio - Stdio transport for spawning server processes
• http - HTTP transport for connecting to HTTP servers
• http-server - HTTP server with actix-web (for hosting MCP servers)
• macros - Procedural macros for defining tools

Re-exports

pub use protocol::CallToolParams;

pub use protocol::CallToolResult;

pub use protocol::JsonRpcError;

pub use protocol::JsonRpcId;

pub use protocol::JsonRpcPayload;

pub use protocol::JsonRpcRequest;

pub use protocol::JsonRpcResponse;

pub use protocol::ListToolsParams;

pub use protocol::ListToolsResult;

pub use protocol::McpCapabilities;

pub use protocol::McpServerInfo;

pub use protocol::McpToolDef;

pub use protocol::ToolContent;

pub use protocol::ToolDefinition;

pub use protocol::ToolInputSchema;

pub use protocol::MCP_PROTOCOL_VERSION;

pub use transport::ClientInfo;

pub use transport::InitializeCapabilities;

pub use transport::InitializeParams;

pub use transport::InitializeResult;

pub use transport::McpServerConnectionConfig;

pub use transport::McpTransport;

pub use transport::McpTransportError;

pub use transport::ServerCapabilities;

pub use transport::ServerInfo;

pub use transport::TransportTypeId;

pub use result::error_result;

pub use result::success_result;

pub use result::tool_err;

pub use result::tool_ok;

pub use result::IntoCallToolResult;

pub use result::ToolResult;

pub use tool::all_tools;

pub use tool::tools_in_group;

pub use tool::BoxFuture;

pub use tool::DynTool;

pub use tool::FnTool;

pub use tool::McpTool;

pub use tool::ToolCallResult;

pub use tool::ToolEntry;

pub use tool::ToolFactory;

pub use tool::ToolProvider;

pub use tool::ToolRegistry;

pub use server::McpServer;

pub use server::McpServerConfig;

pub use server::McpServerConfigBuilder;

pub use server::ServerError;

pub use server::ServerTransport;

pub use hub::McpHub;

pub use stdio::AsyncStdioTransport;stdio

pub use stdio::StdioTransport;stdio

pub use stdio::StdioTransportAdapter;stdio

pub use http::HttpTransport;http

pub use http::HttpTransportAdapter;http

pub use macro_adapter::MacroServer;macros

pub use macro_adapter::MacroServerAdapter;macros

Modules

httphttp

HTTP Transport for MCP Servers

hub

McpHub - Central hub for MCP tool routing across multiple servers.

macro_adaptermacros

Adapter for macro-generated MCP servers.

macrosmacros

Procedural macros for defining MCP servers and tools.

protocol

MCP JSON-RPC Protocol Types

result

Result types for MCP tool implementations.

server

MCP Server configuration and runtime.

stdiostdio

Stdio Transport for MCP Servers

tool

Tool traits and types for MCP servers.

transport

McpTransport - Abstract transport interface for MCP servers.

Macros

fn_tool

Helper macro for creating tools from async functions.

tools

Creates a vector of tools from tool types.

Constants

PROTOCOL_VERSION

Current MCP protocol version supported by this crate.

VERSION

Crate version.