# FastMCP — Python Framework for MCP Servers

> FastMCP is a Python framework for building MCP servers/clients with generated schemas and lifecycle handling. Verified 25154★; pushed 2026-05-13.

## Install

Merge the JSON below into your `.mcp.json`:

## Quick Use

```bash
uv pip install fastmcp
cat > server.py <<'PY'
from fastmcp import FastMCP

mcp = FastMCP("Demo")

@mcp.tool
def add(a: int, b: int) -> int:
    return a + b

if __name__ == "__main__":
    mcp.run()
PY
python server.py
```

## Intro

FastMCP is a Python framework for building MCP servers/clients with generated schemas and lifecycle handling. Verified 25154★; pushed 2026-05-13.

**Best for:** Python teams who want a structured way to ship MCP servers with fewer protocol edge cases

**Works with:** Python 3.x; uv/pip installs; integrates with MCP clients (per docs/README links)

**Setup time:** 5-12 minutes

### Key facts (verified)

- GitHub: 25154 stars · 2010 forks · pushed 2026-05-13.
- License: Apache-2.0 · owner avatar + repo URL verified via GitHub API.
- README-backed entrypoint: `from fastmcp import FastMCP; mcp.run()`.

## Main

- Start from the minimal server example, then move each tool into small, testable Python functions with clear docstrings.

- Keep tool contracts stable: treat schemas and return types as an API, and version changes in your MCP server like any other service.

- Add production concerns early (timeouts, rate limits, auth) and keep a staging server to validate client compatibility.

- Use the project docs links for server/client/app patterns instead of inventing protocol glue by hand.

### README (excerpt)

<div align="center">

<!-- omit in toc -->

<picture>
  <source width="550" media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-4-dark.png">
  <source width="550" media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-4.png">
  <img width="550" alt="FastMCP Logo" src="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-2.png">
</picture>

**FastMCP 🚀**

<strong>Move fast and make things.</strong>

*Made with 💙 by [Prefect](https://www.prefect.io/)*

[![Docs](https://img.shields.io/badge/docs-gofastmcp.com-blue)](https://gofastmcp.com)
[![Discord](https://img.shields.io/badge/community-discord-5865F2?logo=discord&logoColor=white)](https://discord.gg/uu8dJCgttd)
[![PyPI - Version](https://img.shields.io/pypi/v/fastmcp.svg)](https://pypi.org/project/fastmcp)
[![Tests](https://github.com/PrefectHQ/fastmcp/actions/workflows/run-tests.yml/badge.svg)](https://github.com/PrefectHQ/fastmcp/actions/workflows/run-tests.yml)
[![License](https://img.shields.io/github/license/PrefectHQ/fastmcp.svg)](https://github.com/PrefectHQ/fastmcp/blob/main/LICENSE)

<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](https://modelcontextprotocol.io/) (MCP) connects LLMs to tools and data. FastMCP gives you everything you need to go from prototype to production:

```python
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.**


### Source-backed notes

- README shows a minimal server using `FastMCP("Demo")`, a `@mcp.tool` function, and `mcp.run()`.
- README recommends installing via `uv pip install fastmcp` and links to a dedicated docs site.
- Project description frames FastMCP as a higher-level way to build MCP servers/clients without manual schema wiring.

### FAQ

- **Is FastMCP a server or a client?**: README describes both server and client patterns; start by building a server first.
- **Do I need uv?**: README recommends uv, but pip-based installs are also common for Python libraries.
- **How do I keep tool behavior predictable?**: Treat tool schemas as an API contract, add tests, and version breaking changes.

## Source & Thanks

> Created by [PrefectHQ](https://github.com/PrefectHQ). Licensed under Apache-2.0.
>
> [PrefectHQ/fastmcp](https://github.com/PrefectHQ/fastmcp) — ⭐ 25154

Thanks to the upstream maintainers and contributors for publishing this work under an open license.

---

<!-- ZH -->

## Quick Use

```bash
uv pip install fastmcp
cat > server.py <<'PY'
from fastmcp import FastMCP

mcp = FastMCP("Demo")

@mcp.tool
def add(a: int, b: int) -> int:
    return a + b

if __name__ == "__main__":
    mcp.run()
PY
python server.py
```

## Intro

FastMCP 是用于构建 MCP server/client 的 Python 框架，包含工具封装、schema 生成与传输生命周期管理；已验证 25154★，更新于 2026-05-13。

**Best for:** 想用 Python 快速落地 MCP server，并降低协议细节踩坑的团队

**Works with:** Python 3.x；uv/pip 安装；面向 MCP client 的 server/client 侧开发（见 README）

**Setup time:** 5-12 minutes

### Key facts (verified)

- GitHub：25154 stars · 2010 forks；最近更新 2026-05-13。
- 许可证：Apache-2.0；作者头像与仓库链接均已通过 GitHub API 复核。
- README 中可对照的入口：`from fastmcp import FastMCP; mcp.run()`。

## Main

- 先从 README 的最小 server 示例跑通，再把每个工具拆成可测试、带清晰 docstring 的 Python 函数。

- 把工具的 schema/返回值当作 API：保持契约稳定，对破坏性变更做版本化管理。

- 尽早补齐生产化要素（超时、限流、鉴权），并准备一个 staging 环境复核不同 MCP 客户端的兼容性。

- 优先按文档里的 server/client/app 模式扩展，不要手写一堆协议胶水。

### README (excerpt)

<div align="center">

<!-- omit in toc -->

<picture>
  <source width="550" media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-4-dark.png">
  <source width="550" media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-4.png">
  <img width="550" alt="FastMCP Logo" src="https://raw.githubusercontent.com/PrefectHQ/fastmcp/main/docs/assets/brand/f-watercolor-waves-2.png">
</picture>

**FastMCP 🚀**

<strong>Move fast and make things.</strong>

*Made with 💙 by [Prefect](https://www.prefect.io/)*

[![Docs](https://img.shields.io/badge/docs-gofastmcp.com-blue)](https://gofastmcp.com)
[![Discord](https://img.shields.io/badge/community-discord-5865F2?logo=discord&logoColor=white)](https://discord.gg/uu8dJCgttd)
[![PyPI - Version](https://img.shields.io/pypi/v/fastmcp.svg)](https://pypi.org/project/fastmcp)
[![Tests](https://github.com/PrefectHQ/fastmcp/actions/workflows/run-tests.yml/badge.svg)](https://github.com/PrefectHQ/fastmcp/actions/workflows/run-tests.yml)
[![License](https://img.shields.io/github/license/PrefectHQ/fastmcp.svg)](https://github.com/PrefectHQ/fastmcp/blob/main/LICENSE)

<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](https://modelcontextprotocol.io/) (MCP) connects LLMs to tools and data. FastMCP gives you everything you need to go from prototype to production:

```python
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.**


### Source-backed notes

- README 给出最小 server 示例：`FastMCP("Demo")`、`@mcp.tool`、以及 `mcp.run()` 启动。
- README 推荐用 `uv pip install fastmcp` 安装，并链接到独立文档站点。
- README 描述 FastMCP 用于抽象 MCP 的 schema/生命周期细节，减少手写协议逻辑。

### FAQ

- **FastMCP 是 server 还是 client？**：README 同时提到 server/client 模式；建议先从 server 落地开始。
- **必须用 uv 吗？**：README 推荐 uv；但作为 Python 依赖也可以按团队习惯使用 pip/虚拟环境。
- **怎么保证工具行为可预测？**：把 schema 当作契约，加测试，并对破坏性改动做版本化发布。

## Source & Thanks

> Created by [PrefectHQ](https://github.com/PrefectHQ). Licensed under Apache-2.0.
>
> [PrefectHQ/fastmcp](https://github.com/PrefectHQ/fastmcp) — ⭐ 25154


---
Source: https://tokrepo.com/en/workflows/fastmcp-python-framework-for-mcp-servers
Author: MCP Hub