python-sdk

# MCP Python SDK

<div align="center">

<strong>Python implementation of the Model Context Protocol (MCP)</strong>

[![PyPI][pypi-badge]][pypi-url]
[![MIT licensed][mit-badge]][mit-url]
[![Python Version][python-badge]][python-url]
[![Documentation][docs-badge]][docs-url]
[![Protocol][protocol-badge]][protocol-url]
[![Specification][spec-badge]][spec-url]

</div>

## Documentation

**The documentation lives at <https://py.sdk.modelcontextprotocol.io/>.**

It has a [Get started guide](https://py.sdk.modelcontextprotocol.io/get-started/), [What's new in v2](https://py.sdk.modelcontextprotocol.io/whats-new/), the [API reference](https://py.sdk.modelcontextprotocol.io/api/mcp/), and the [migration guide](https://py.sdk.modelcontextprotocol.io/migration/).

## What is MCP?

The [Model Context Protocol](https://modelcontextprotocol.io) lets you build servers that expose data and functionality to LLM applications in a secure, standardized way. Think of it like a web API, but designed for LLM interactions. With this SDK you can:

- **Build MCP servers** that expose tools, resources, and prompts to any MCP host
- **Build MCP clients** that connect to any MCP server
- Speak every standard transport: stdio, Streamable HTTP, and SSE

## Requirements

Python 3.11+.

## Installation

```bash
uv add "mcp[cli]"      # or: pip install "mcp[cli]"
```

The `cli` extra adds the `mcp` command-line tool (`mcp dev`, `mcp run`, `mcp install`) on top of the SDK; install plain `mcp` if you don't need it. For one-off commands, `uv run --with "mcp[cli]" mcp ...` works without a project.

## A server in 15 lines

Create a `server.py`:

<!-- snippet-source docs_src/index/tutorial001.py -->
```python
from mcp.server import MCPServer

mcp = MCPServer("Demo")


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


@mcp.resource("greeting://{name}")
def greeting(name: str) -> str:
    """Greet someone by name."""
    return f"Hello, {name}!"
```

_Full example: [docs_src/index/tutorial001.py](https://github.com/modelcontextprotocol/python-sdk/blob/main/docs_src/index/tutorial001.py)_
<!-- /snippet-source -->

That's a complete MCP server: one tool, one templated resource. Open it in the [MCP Inspector](https://github.com/modelcontextprotocol/inspector):

```bash
uv run mcp dev server.py
```

Call `add` with `a=1`, `b=2` and you get `3` back.

Notice what you did **not** write: no JSON Schema (`a: int, b: int` _is_ the schema), no request parsing, no validation code, no protocol handling. Two type-hinted Python functions and a docstring.

[Get started](https://py.sdk.modelcontextprotocol.io/get-started/) takes it from here.

## A client in 10 lines

The same package is a full MCP **client**. Serve `server.py` over HTTP:

```bash
uv run mcp run server.py --transport streamable-http
```

then point a `Client` at it:

```python
import asyncio

from mcp import Client


async def main() -> None:
    async with Client("http://localhost:8000/mcp") as c