This repository is the official Model Context Protocol (MCP) reference implementation, containing seven standalone servers (everything, filesystem, memory, sequentialthinking, fetch, git, time) written in TypeScript or Python. These servers demonstrate the full MCP protocol—tools, prompts, resources, transports (stdio, SSE, Streamable HTTP), subscriptions, sampling, elicitation, tasks, and structured content. They are designed as educational examples for developers building their own MCP servers, not as production-ready solutions. The codebase is well-structured with consistent patterns (server factory, transport abstraction, security-focused path validation, atomic file operations, knowledge graph management) and includes extensive test suites. While actively maintained, some Python servers show drift from the latest MCP SDK (v2 API renames in progress), and the Everything server's demo code is tightly coupled to experimental protocol features. The repository also serves as a central hub for the MCP ecosystem via a curated community resource directory (ADDITIONAL.md).

This is the official Python SDK for the Model Context Protocol (MCP), a protocol for integrating AI models with external tools, resources, and prompts. The SDK provides both a high-level decorator-based API (MCPServer) and a low-level handler-based API (Server) for building MCP servers, along with a full client implementation (Client) for connecting to servers. It supports multiple transports (stdio, SSE, streamable HTTP), OAuth 2.0 authentication, caching, subscriptions, progress reporting, structured output, and an extension system. The codebase is well-structured with clean separation of concerns, extensive test coverage (unit, integration, documentation-sourced), and reusable patterns for authentication, caching, path security, and URI template parsing. It is actively maintained with recent commits and a comprehensive CI pipeline.

This repository is the official home of the Model Context Protocol (MCP), an open standard defining how AI assistants discover and invoke external tools, resources, and prompts over JSON-RPC. In production it operates as a specification and governance hub: versioned TypeScript protocol schemas (2024-11-05 through 2026-07-28 plus draft) are compiled into JSON Schema artifacts, human-readable specification docs are generated and published, and a SEP (Specification Enhancement Proposal) process is automated by a GitHub bot that detects proposals, enforces lifecycle transitions, pings authors, and sends Discord notifications. The architecture is not a monolithic service or microservices; it is a mixed content-plus-tooling repository. The primary code components are the TypeScript schema sources, the schema/doc generation scripts (scripts/generate-schemas.ts, scripts/render-seps.ts), and the sep-automation Node.js application (tools/sep-automation), which uses explicit interfaces for the GitHub client, hooks, and workflow rules. Core data flows are: TypeScript interfaces -> JSON Schema -> published schema files and examples; SEP markdown -> rendered MDX documentation; and GitHub issue/PR events -> SEP state machine -> comments and Discord webhooks. External dependencies include Octokit/GitHub App auth, Discord webhooks, TypeDoc/typescript-json-schema, Mintlify for docs, and Hugo for the blog. Although classified as an application repo because of its runnable tooling, CI/CD, and unit tests, the dominant character is an open-standards documentation and governance project. It is actively maintained, enforces a conformance-testing mandate for SDKs, and contains well-crafted modular code. The main risks are content-version overhead (six dated spec snapshots plus draft, duplicated docs, frozen historical SEPs) and process/doc drift, not software decay.

This repository is the official Go SDK for the Model Context Protocol (MCP), a client/server protocol for AI tool orchestration. It provides production-grade implementations of MCP servers and clients, supporting multiple transports (stdio, SSE, streamable HTTP, in-memory) and full OAuth 2.0 authorization code flows with enterprise extensions. The SDK features typed tool handlers with automatic JSON Schema inference, a middleware system for custom processing, generic pagination helpers, and a schema cache for performance in stateless deployments. It maintains backward compatibility with multiple MCP protocol versions (2024-11-05 through 2026-07-28) using compatibility flags and includes conformance tests against the official MCP test suite. The architecture separates JSON-RPC 2.0 wire protocol, transport abstractions, and core client/server logic, with internal packages for low-level RPC handling, OAuth test infrastructure, and configuration compatibility. While the SDK is actively maintained and well-tested, it carries some technical debt from deprecated features (roots, sampling, logging) and protocol version complexity.