Everything

Ships in the modelcontextprotocol/servers monorepo as the kitchen-sink reference. Most people who run it are writing their own MCP client or server and need a controlled counter-party to verify their implementation handles every primitive. What it does: - Exposes demo tools: echo, add, and longRunningOperation with configurable duration - Serves a static resource and a dynamic resource whose content changes per read - Defines prompt templates with and without arguments - Issues a sampling request — one of the rarer MCP primitives — so clients can be tested end-to-end - Emits progress notifications during long-running operations - Logs every transport message at the info level for client-side debugging Example: Writing a new MCP client? Start it against the Everything server. If tool/call, resources/read, prompts/get, and sampling/createMessage all round-trip cleanly, the client is conformant. Failures here point at which primitive is broken before a real server is ever involved. Setup: No configuration required. "npx -y @modelcontextprotocol/server-everything" is the whole install. Transport: stdio only. Notes: Not meant for real workloads. The echo and add tools are deliberately trivial so the surface is predictable across versions. Use it for conformance testing, new-client onboarding, and bug reproducers — not as a building block inside a real agent.