FastMCP
A Python framework for building Model Context Protocol servers, clients and interactive apps, generating tool schemas, validation and documentation automatically from ordinary Python functions.
FastMCP is a full application framework for the Model Context Protocol (MCP), which connects LLMs to tools and data. It covers three areas: servers that expose Python functions as MCP-compliant tools, resources and prompts; apps that give those tools interactive UIs rendered directly in the conversation; and clients that connect to any MCP server, local or remote, programmatic or from the command line.
Declaring a tool as an ordinary Python function is enough for FastMCP to generate its schema, validation and documentation, and connecting to a server over a URL handles transport negotiation, authentication and the protocol lifecycle automatically. A companion project, FastMCP for TypeScript, offers a matching set of features for TypeScript users.
It is written in Python and licensed Apache-2.0. Its maker, Prefect, also offers a separate paid product, Prefect Horizon, for deploying and governing MCP servers across a team.