PrefectHQ / fastmcp
🚀 The fast, Pythonic way to build MCP servers and clients.
AI Architecture Analysis
This repository is indexed by RepoMind. By analyzing PrefectHQ/fastmcp in our AI interface, you can instantly generate complete architecture diagrams, visualize control flows, and perform automated security audits across the entire codebase.
Our Agentic Context Augmented Generation (Agentic CAG) engine loads full source files into context, avoiding the fragmentation of traditional RAG systems. Ask questions about the architecture, dependencies, or specific features to see it in action.
Repository Summary (README)
PreviewFastMCP 🚀
<strong>Move fast and make things.</strong>
Made with 💙 by Prefect
<a href="https://trendshift.io/repositories/13266" target="_blank"><img src="https://trendshift.io/api/badge/repositories/13266" alt="prefecthq%2Ffastmcp | Trendshift" style="width: 250px; height: 55px;" width="250" height="55"/></a>
</div>The Model Context Protocol (MCP) connects LLMs to tools and data. FastMCP gives you everything you need to go from prototype to production:
from fastmcp import FastMCP
mcp = FastMCP("Demo 🚀")
@mcp.tool
def add(a: int, b: int) -> int:
"""Add two numbers"""
return a + b
if __name__ == "__main__":
mcp.run()
Why FastMCP
Building an effective MCP application is harder than it looks. FastMCP handles all of it. Declare a tool with a Python function, and the schema, validation, and documentation are generated automatically. Connect to a server with a URL, and transport negotiation, authentication, and protocol lifecycle are managed for you. You focus on your logic, and the MCP part just works: with FastMCP, best practices are built in.
That's why FastMCP is the standard framework for working with MCP. FastMCP 1.0 was incorporated into the official MCP Python SDK in 2024. Today, the actively maintained standalone project is downloaded a million times a day, and some version of FastMCP powers 70% of MCP servers across all languages.
FastMCP has three pillars:
<table> <tr> <td align="center" valign="top" width="33%"> <a href="https://gofastmcp.com/servers/server"> <img src="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/images/servers-card.png" alt="Servers" /> <br /><strong>Servers</strong> </a> <br />Expose tools, resources, and prompts to LLMs. </td> <td align="center" valign="top" width="33%"> <a href="https://gofastmcp.com/apps/overview"> <img src="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/images/apps-card.png" alt="Apps" /> <br /><strong>Apps</strong> </a> <br />Give your tools interactive UIs rendered directly in the conversation. </td> <td align="center" valign="top" width="33%"> <a href="https://gofastmcp.com/clients/client"> <img src="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/images/clients-card.png" alt="Clients" /> <br /><strong>Clients</strong> </a> <br />Connect to any MCP server — local or remote, programmatic or CLI. </td> </tr> </table>Servers wrap your Python functions into MCP-compliant tools, resources, and prompts. Clients connect to any server with full protocol support. And Apps give your tools interactive UIs rendered directly in the conversation.
Ready to build? Start with the installation guide or jump straight to the quickstart. When you're ready to deploy, Prefect Horizon offers free hosting for FastMCP users.
Installation
We recommend installing FastMCP with uv:
uv pip install fastmcp
For full installation instructions, including verification and upgrading, see the Installation Guide.
Upgrading? We have guides for:
📚 Documentation
FastMCP's complete documentation is available at gofastmcp.com, including detailed guides, API references, and advanced patterns.
Documentation is also available in llms.txt format, which is a simple markdown standard that LLMs can consume easily:
llms.txtis essentially a sitemap, listing all the pages in the documentation.llms-full.txtcontains the entire documentation. Note this may exceed the context window of your LLM.
Community: Join our Discord server to connect with other FastMCP developers and share what you're building.
Contributing
We welcome contributions! See the Contributing Guide for setup instructions, testing requirements, and PR guidelines.