Crate pmcp 

MCP SDK for Rust

A high-quality Rust implementation of the Model Context Protocol (MCP) SDK.

This crate provides both client and server implementations of MCP with:

• Full protocol compatibility with the TypeScript SDK
• Zero-copy parsing where possible
• Comprehensive type safety
• Multiple transport options (stdio, HTTP/SSE, WebSocket)
• Built-in authentication support

Quick Start

Client Example

use pmcp::{Client, StdioTransport, ClientCapabilities};

// Create a client with stdio transport
let transport = StdioTransport::new();
let mut client = Client::new(transport);

// Initialize the connection
let server_info = client.initialize(ClientCapabilities::default()).await?;

// List available tools
let tools = client.list_tools(None).await?;

Server Example

use pmcp::{Server, ServerCapabilities, ToolHandler};
use async_trait::async_trait;
use serde_json::Value;

struct MyTool;

#[async_trait]
impl ToolHandler for MyTool {
    async fn handle(&self, args: Value, _extra: pmcp::RequestHandlerExtra) -> Result<Value, pmcp::Error> {
        Ok(serde_json::json!({"result": "success"}))
    }
}

let server = Server::builder()
    .name("my-server")
    .version("1.0.0")
    .capabilities(ServerCapabilities::default())
    .tool("my-tool", MyTool)
    .build()?;

// Run with stdio transport
server.run_stdio().await?;

Re-exports

pub use client::Client;

pub use client::ClientBuilder;

pub use error::Error;

pub use error::ErrorCode;

pub use error::Result;

pub use server::cancellation::RequestHandlerExtra;Non-WebAssembly

pub use server::auth;Non-WebAssembly

pub use server::simple_prompt::SimplePrompt;Non-WebAssembly

pub use server::simple_prompt::SyncPrompt;Non-WebAssembly

pub use server::simple_resources::DynamicResourceHandler;Non-WebAssembly

pub use server::simple_resources::ResourceCollection;Non-WebAssembly

pub use server::simple_resources::StaticResource;Non-WebAssembly

pub use server::simple_tool::SimpleTool;Non-WebAssembly

pub use server::simple_tool::SyncTool;Non-WebAssembly

pub use server::typed_tool::SimpleToolExt;Non-WebAssembly

pub use server::typed_tool::SyncToolExt;Non-WebAssembly

pub use server::typed_tool::TypedSyncTool;Non-WebAssembly

pub use server::typed_tool::TypedTool;Non-WebAssembly

pub use server::typed_tool::TypedToolWithOutput;Non-WebAssembly

pub use server::PromptHandler;Non-WebAssembly

pub use server::ResourceHandler;Non-WebAssembly

pub use server::SamplingHandler;Non-WebAssembly

pub use server::Server;Non-WebAssembly

pub use server::ServerBuilder;Non-WebAssembly

pub use server::ToolHandler;Non-WebAssembly

pub use shared::StdioTransport;Non-WebAssembly

pub use shared::batch::BatchRequest;

pub use shared::batch::BatchResponse;

pub use shared::uri_template::UriTemplate;

pub use shared::AuthMiddleware;

pub use shared::LoggingMiddleware;

pub use shared::Middleware;

pub use shared::MiddlewareChain;

pub use shared::RetryMiddleware;

pub use shared::Transport;

pub use shared::WebSocketConfig;websocket and non-WebAssembly

pub use shared::WebSocketTransport;websocket and non-WebAssembly

pub use shared::HttpConfig;http and non-WebAssembly

pub use shared::HttpTransport;http and non-WebAssembly

pub use types::AuthInfo;

pub use types::AuthScheme;

pub use types::CallToolRequest;

pub use types::CallToolResult;

pub use types::ClientCapabilities;

pub use types::ClientNotification;

pub use types::ClientRequest;

pub use types::CompleteRequest;

pub use types::CompleteResult;

pub use types::CompletionArgument;

pub use types::CompletionReference;

pub use types::Content;

pub use types::CreateMessageParams;

pub use types::CreateMessageRequest;

pub use types::CreateMessageResult;

pub use types::GetPromptResult;

pub use types::Implementation;

pub use types::IncludeContext;

pub use types::ListResourcesResult;

pub use types::ListToolsResult;

pub use types::LoggingLevel;

pub use types::MessageContent;

pub use types::ModelPreferences;

pub use types::ProgressNotification;

pub use types::ProgressToken;

pub use types::PromptMessage;

pub use types::ProtocolVersion;

pub use types::ReadResourceResult;

pub use types::RequestId;

pub use types::ResourceInfo;

pub use types::Role;

pub use types::RootsCapabilities;

pub use types::SamplingCapabilities;

pub use types::SamplingMessage;

pub use types::ServerCapabilities;

pub use types::ServerNotification;

pub use types::ServerRequest;

pub use types::TokenUsage;

pub use types::ToolCapabilities;

pub use types::ToolInfo;

pub use types::CallToolResult as ToolResult;

pub use utils::BatchingConfig;Non-WebAssembly

pub use utils::DebouncingConfig;Non-WebAssembly

pub use utils::MessageBatcher;Non-WebAssembly

pub use utils::MessageDebouncer;Non-WebAssembly

Modules

client

MCP client implementation.

error

Error types for the MCP SDK.

runtime

Runtime abstraction layer for platform-independent async execution

server

MCP server implementation.

shared

Shared components used by both client and server.

simdsimd

SIMD optimizations for PMCP performance-critical operations Provides vectorized implementations of JSON parsing and string operations

types

Core protocol types for MCP.

utils

Utility modules for the MCP SDK.

Macros

context_or_new

Macro to get current context or create new one.

debug_correlated

Log debug with correlation.

error_correlated

Log error with correlation.

info_correlated

Log info with correlation.

log_correlated

Helper macros for correlated logging.

warn_correlated

Log warning with correlation.

with_context

Macro to run code with request context.

Constants

DEFAULT_PROTOCOL_VERSION

Default protocol version to use for negotiation

DEFAULT_REQUEST_TIMEOUT_MS

Default request timeout in milliseconds

LATEST_PROTOCOL_VERSION

Protocol version constants

SUPPORTED_PROTOCOL_VERSIONS

List of all protocol versions supported by this SDK

Functions

log

Server-side logging function (placeholder for examples).

Attribute Macros

async_trait