What it does
A comprehensive reference implementation server that demonstrates all features of the Model Context Protocol. It showcases how prompts, resources, and other protocol mechanisms work within a single server. Built and maintained by the MCP steering group, it serves primarily as an educational tool and test harness for developers building MCP servers and for validation of MCP client implementations.
Who it's for
Developers creating new MCP servers who need working examples of protocol patterns, maintainers of MCP SDKs across languages validating their implementations, and engineers learning how prompts, resources, and protocol features integrate.
Common use cases
- Validate MCP client implementations by testing against a feature-complete, protocol-compliant server
- Study protocol design: how prompts, resources, and other features are structured and exposed
- Verify MCP SDK behavior during language-specific SDK development and iteration
- Use as a reference when designing domain-specific MCP servers
Setup pitfalls
- CI tests are currently failing — review recent changes before using for validation or development work
- High-risk server due to filesystem write access and network capabilities — run only in isolated, trusted, or sandboxed environments
- Reference implementation, not production-ready — intended for learning, testing, and SDK development, not production workloads