Model Context Protocol

Official MCP server that fetches web content and converts HTML pages into markdown for model-friendly reading.

Official visual testing and debugging tool for Model Context Protocol servers.

Official reference MCP server that gives Claude persistent memory through a local knowledge graph of entities, relations, and observations, stored in a file on your own machine.

Official C# SDK for Model Context Protocol servers and clients, maintained by the MCP project in collaboration with Microsoft, with NuGet packages for core MCP APIs, hosting and dependency injection extensions, ASP.NET Core HTTP servers, samples, API documentation, and cross-application access support.

Official Go SDK for Model Context Protocol servers and clients, maintained by the MCP project in collaboration with Google, with packages for MCP, JSON-RPC, OAuth primitives, OAuth protected-resource metadata, clients, servers, transports, examples, and conformance work.

Official Java SDK for Model Context Protocol clients and servers, maintained in collaboration with Spring AI, with Java 17+ support, Maven artifacts, synchronous and asynchronous APIs, Reactive Streams, Project Reactor, JDK HttpClient, Servlet transport, JSON binding modules, and conformance tests.

Official Kotlin Multiplatform SDK for Model Context Protocol clients and servers, maintained in collaboration with JetBrains, with JVM, Native, JS, and Wasm targets, coroutine APIs, Gradle artifacts, Ktor integration, stdio, SSE, Streamable HTTP, WebSocket, tools, resources, prompts, sampling, and roots.

Official PHP SDK for Model Context Protocol clients and servers, built with the PHP Foundation and Symfony project, published as `mcp/sdk` on Packagist, with framework-agnostic APIs, attribute discovery, manual registration, stdio and HTTP transports, sessions, tools, resources, prompts, sampling, and logs.

Official Python SDK for Model Context Protocol clients and servers, published as the `mcp` package on PyPI, with FastMCP server helpers, client support, tools, resources, prompts, stdio, SSE, Streamable HTTP, authentication, elicitation, sampling, logging, and standalone development tools.

Official Ruby SDK for Model Context Protocol clients and servers, published as the `mcp` gem with JSON-RPC handling, tool, prompt, and resource registration, stdio and Streamable HTTP transports, Rack/Rails integration, roots, sampling, elicitation, logging, cancellation, pagination, and RubyGems metadata.

Official Rust SDK for Model Context Protocol clients and servers, published as the `rmcp` crate with tokio async runtime support, server and client features, tool macros, resources, prompts, sampling, roots, logging, completions, notifications, Streamable HTTP, child-process transports, and OAuth support.

Official Swift SDK for Model Context Protocol clients and servers, with Swift Package Manager installation, Swift 6+ support, Apple platform availability, MCP client and server APIs, stdio and HTTP transports, tools, resources, prompts, sampling, authentication, and conformance executables.

Official TypeScript SDK for Model Context Protocol clients and servers, with the production v1 `@modelcontextprotocol/sdk` package, active v2 server and client package work, Node.js, Bun, and Deno support, transports, OAuth helpers, tools, resources, prompts, examples, and API documentation.

Official reference MCP server that gives Claude a structured sequential thinking tool for breaking complex problems into ordered, revisable thought steps, all processed locally with no external calls.

Official MCP server that gives Claude current time and timezone conversion tools using IANA timezone names.