What is this?
FastMCP is an open-source Python framework for building MCP (Model Context Protocol) applications — the layer that connects LLMs to tools and data. It covers servers, clients, and interactive apps.
FastMCP is an open-source Python framework for building MCP (Model Context Protocol) applications — the layer that connects LLMs to tools and data. It covers servers, clients, and interactive apps.So is it a framework or a library?A full application framework, not a thin wrapper: servers wrap your Python functions into MCP tools, resources, and prompts, clients connect to any MCP server, and apps give tools interactive UIs right in the conversation.
A full application framework, not a thin wrapper: servers wrap your Python functions into MCP tools, resources, and prompts, clients connect to any MCP server, and apps give tools interactive UIs right in the conversation.How do I add it to my project?The README recommends adding FastMCP with uv; the Installation Guide at gofastmcp.com also covers verification, upgrading, and migrations from FastMCP 2/3 or the low-level MCP SDK.
The README recommends adding FastMCP with uv; the Installation Guide at gofastmcp.com also covers verification, upgrading, and migrations from FastMCP 2/3 or the low-level MCP SDK.Do I need to know the MCP protocol internals to use it?Almost none of it: declare a tool as a plain Python function and the schema, validation, and documentation are generated automatically; on the client side, transport negotiation, authentication, and lifecycle are managed for you.
Almost none of it: declare a tool as a plain Python function and the schema, validation, and documentation are generated automatically; on the client side, transport negotiation, authentication, and lifecycle are managed for you.Is this only for Python developers?It is aimed at developers building MCP integrations in Python; if your stack is TypeScript, the same team maintains FastMCP for TypeScript with the same pillars (npm install @prefecthq/fastmcp-ts).
It is aimed at developers building MCP integrations in Python; if your stack is TypeScript, the same team maintains FastMCP for TypeScript with the same pillars (npm install @prefecthq/fastmcp-ts).Does it need any particular OS or hardware?No: it is a pure Python framework you add with uv or pip, so it runs anywhere Python runs; the README names no OS or hardware requirements.
No: it is a pure Python framework you add with uv or pip, so it runs anywhere Python runs; the README names no OS or hardware requirements.What does an MCP App give me that a regular tool doesn't?A regular tool returns text; an App renders an interactive UI directly inside the LLM conversation, so users interact with your interface in the chat instead of a terminal.
A regular tool returns text; an App renders an interactive UI directly inside the LLM conversation, so users interact with your interface in the chat instead of a terminal.There's an official MCP Python SDK — how does FastMCP relate to it?FastMCP 1.0 was incorporated into the official SDK in 2024, but this standalone project is the actively maintained one — downloaded about a million times a day, and some version of it powers 70% of MCP servers across all languages.
FastMCP 1.0 was incorporated into the official SDK in 2024, but this standalone project is the actively maintained one — downloaded about a million times a day, and some version of it powers 70% of MCP servers across all languages.What's Prefect Horizon, and do I need it to use FastMCP?No — Horizon is an optional enterprise gateway from the same team for governing MCP at company scale: private registry, SSO, tool-level RBAC, audit logs. You start with FastMCP and reach for Horizon when scaling across teams.
No — Horizon is an optional enterprise gateway from the same team for governing MCP at company scale: private registry, SSO, tool-level RBAC, audit logs. You start with FastMCP and reach for Horizon when scaling across teams.Where are the docs, and can my LLM read them too?Complete documentation is at gofastmcp.com — guides, API references, advanced patterns — plus llms.txt (a sitemap of all doc pages) and llms-full.txt (the entire docs, which may exceed your LLM's context window).
Complete documentation is at gofastmcp.com — guides, API references, advanced patterns — plus llms.txt (a sitemap of all doc pages) and llms-full.txt (the entire docs, which may exceed your LLM's context window).What are similar projects?awesome-mcp-servers, mcp-use, fastapi_mcp, gateway, awesome-jev-live, python-sdk, Benzi, awesome-llm-apps
awesome-mcp-servers, mcp-use, fastapi_mcp, gateway, awesome-jev-live, python-sdk, Benzi, awesome-llm-appsWhich topics is it in?mcp-servers, llm-tools, mcp-tools, json-schema, mcp-client, boilerplate, protocol, llms, model-context-protocol, authentication, agents, mcp-server
mcp-servers, llm-tools, mcp-tools, json-schema, mcp-client, boilerplate, protocol, llms, model-context-protocol, authentication, agents, mcp-server