An open-source Fastify plugin maintained by the Platformatic team for scaffolding MCP-compliant servers, covering protocol negotiation, SSE/stdio transports, Redis-backed horizontal scaling, OAuth 2.1 authorization, and newer spec features like tasks and elicitation — but it is a development framework, not a turnkey tool server, so actual security and functionality depend entirely on the integrator's own implementation.
@platformatic/mcp is a Fastify plugin that implements a Model Context Protocol (MCP) server over JSON-RPC 2.0. It is not a standalone server with a fixed toolset — it's a framework developers use inside their own Fastify application to register tools, resources, and prompts. It supports protocol version negotiation (latest 2025-11-25, negotiating down to 2025-06-18, 2025-03-26, and 2024-11-05), both HTTP/SSE and stdio transports, Redis-backed session storage and message broadcasting for horizontal scaling across instances, and built-in OAuth 2.1 authorization, TypeBox/AJV schema validation, input sanitization, experimental task-augmented tool calls, and elicitation (form and URL modes).
Install via npm: npm install @platformatic/mcp (optionally npm install @sinclair/typebox for typed schema validation). Register the plugin in a Fastify app with await app.register(mcpPlugin, { ... }), then define tools/resources/prompts with app.mcpAddTool / app.mcpAddResource / app.mcpAddPrompt. For stdio transport, call the exported runStdioServer(app, options) instead of app.listen.