MCP Python SDK

Official Python SDK for building Model Context Protocol servers and clients.

Free· Free, MIT-licensed open source.MCP Servers

Best for

Python teams that want to expose internal APIs, data, or agents to Claude Desktop, Cursor, VS Code, and other MCP hosts using the reference-quality first-party SDK.

Skip if

Non-Python shops (use the TypeScript, Kotlin, or Rust SDKs instead) or teams that want a hosted, no-code MCP server builder without writing any Python.

The MCP Python SDK is the official Python implementation of Anthropic's Model Context Protocol, the open standard for connecting LLM applications to external tools, data sources, and prompt libraries. It gives Python developers a batteries-included framework for building both MCP servers (which expose capabilities to LLM hosts like Claude Desktop, Cursor, VS Code, Zed, and any custom client) and MCP clients (which consume those capabilities from local or remote servers). The core promise is that you write ordinary typed Python functions and decorate them; the SDK handles JSON-RPC framing, request routing, schema generation from type hints, capability negotiation, session lifecycle, and the transport layer. Three transports ship in the box: stdio for local subprocess-style servers, Streamable HTTP for modern remote deployment, and SSE for backward-compatible browser and proxy scenarios. The CLI extra adds `mcp dev` for interactive debugging with the MCP Inspector, `mcp run` for local execution, and `mcp install` for one-command registration into Claude Desktop. Typical workflows include exposing an internal database or REST API as callable LLM tools, packaging a documentation corpus as MCP resources for RAG, publishing reusable prompt templates, wrapping legacy Python scientific or automation code so agents can drive it, and writing agentic clients that stitch multiple MCP servers together. v2 is the current stable line, rearchitected against the 2026-07-28 MCP specification, while the v1.x branch is maintained for security fixes. Requires Python 3.10 or later.

Editor's take

If you are building MCP servers in Python, this is the SDK to use — there is no meaningful competitor, and the type-hint-to-schema ergonomics are genuinely delightful. Just pin your version carefully: the v1 to v2 jump was real, and the spec is still a moving target through 2026.

— The AI Tool Bible editorial team

Pros

✅ Official, first-party implementation maintained by the MCP working group, so it tracks the spec faster than community ports.
✅ Type-hint-driven: decorate a typed function and the SDK derives the JSON Schema, argument validation, and tool metadata automatically.
✅ Supports all three transports (stdio, Streamable HTTP, SSE) with the same server code, so local and remote deployments share one codebase.
✅ Bundled CLI (`mcp dev`, `mcp run`, `mcp install`) makes the inner loop of building and testing a server genuinely fast.
✅ Symmetric client API lets the same package power agentic apps that orchestrate multiple MCP servers, not just expose them.
✅ MIT-licensed and pip/uv installable with zero paid dependencies.

Cons

⚠️ Spec is still evolving; v2 broke compatibility with v1.x, and future spec revisions may require migration work again.
⚠️ Requires Python 3.10+, ruling out legacy environments still pinned to 3.8 or 3.9.
⚠️ Documentation and cookbook coverage lag the pace of API changes; some patterns you find on GitHub or blogs are already stale.
⚠️ Async-first design (anyio under the hood) has a learning curve for teams whose codebase is entirely synchronous.
⚠️ You still have to run and secure the server yourself — no hosted registry, discovery, or auth layer is provided out of the box.

Use cases

Exposing internal REST APIs as MCP tools for Claude DesktopWrapping a Postgres or SQLite database as an MCP serverPublishing a documentation corpus as MCP resources for RAGSharing reusable prompt templates across an orgBuilding agentic Python clients that call multiple MCP serversAdding MCP tool support to a custom AI IDE or chat appPrototyping new MCP servers with `mcp dev` and the InspectorOne-command installation of dev tools into Claude Desktop