Practical MCP with FastMCP & LangChain

What Is FastMCP Then?

FastMCP was originally created by Jeremiah Lowin as a developer-friendly Python framework for building MCP servers. It's sometimes called FastMCP 1.0 to distinguish it from the later version that forked and evolved independently.

At the time MCP was very new, and writing servers required handling a lot of boilerplate.

FastMCP solved that by:

• Letting you declare tools with decorators.
• Handling JSON-RPC automatically.
• Managing transport details.
• Reducing friction.

It became popular quickly. Anthropic incorporated the core of FastMCP 1.0 into the official MCP Python SDK. That's why, in this guide, we used:

from