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# 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>
> [!NOTE]
> **This is v2 of the MCP Python SDK, the current stable release line.** It is a major rework of the SDK, both to support the [2026-07-28 MCP specification](https://modelcontextprotocol.io/specification/2026-07-28) (and every earlier revision) and to fix long-standing architectural issues. Coming from v1? See [What's new in v2](https://py.sdk.modelcontextprotocol.io/whats-new/) for the tour of what changed and the [migration guide](https://py.sdk.modelcontextprotocol.io/migration/) for every breaking change.
>
> **Not ready to migrate?** v1.x lives on the [`v1.x` branch](https://github.com/modelcontextprotocol/python-sdk/tree/v1.x), continues to receive critical bug fixes and security patches, and is documented at <https://py.sdk.modelcontextprotocol.io/v1/>. Since `pip install mcp` now installs 2.x, keep a `<2` upper bound on your requirement (for example `mcp>=1.28,<2`) until you've migrated.
>
> Something rough, confusing, or broken? [Open an issue](https://github.com/modelcontextprotocol/python-sdk/issues/new?template=v2-feedback.yaml) or find us in [#python-sdk-dev on the MCP Contributors Discord](https://discord.gg/6CSzBmMkjX).
## 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 3.10+.
## 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 client:
result = await client.call_tool("add", {"a": 1, "b": 2})
print(result.structured_content) # {'result': 3}
asyncio.run(main())
```
A URL means Streamable HTTP, the transport you deploy. `Client` can also launch a local server as a stdio subprocess or take any custom transport; [Clients](https://py.sdk.modelcontextprotocol.io/client/) has the rest.
## Contributing
We are passionate about supporting contributors of all levels of experience and would love to see you get involved in the project. See the [contributing guide](https://github.com/modelcontextprotocol/python-sdk/blob/main/CONTRIBUTING.md) to get started.
## License
This project is licensed under the MIT License. See the [LICENSE](https://github.com/modelcontextprotocol/python-sdk/blob/main/LICENSE) file for details.
[pypi-badge]: https://img.shields.io/pypi/v/mcp.svg
[pypi-url]: https://pypi.org/project/mcp/
[mit-badge]: https://img.shields.io/pypi/l/mcp.svg
[mit-url]: https://github.com/modelcontextprotocol/python-sdk/blob/main/LICENSE
[python-badge]: https://img.shields.io/pypi/pyversions/mcp.svg
[python-url]: https://www.python.org/downloads/
[docs-badge]: https://img.shields.io/badge/docs-python--sdk-blue.svg
[docs-url]: https://py.sdk.modelcontextprotocol.io/
[protocol-badge]: https://img.shields.io/badge/protocol-modelcontextprotocol.io-blue.svg
[protocol-url]: https://modelcontextprotocol.io
[spec-badge]: https://img.shields.io/badge/spec-spec.modelcontextprotocol.io-blue.svg
[spec-url]: https://modelcontextprotocol.io/specification/latest
