FastMCP: Pythonic Tools for Predictable LLM Agents

FastMCP isn’t just another Python wrapper for MCP servers and clients; it’s a modest attempt to make the development experience feel less like a guessing game. While the core protocol can be terse, the library hands you a ready‑made toolbox that tries to keep the code you write readable and maintainable. Here’s the thing: every helper function comes pre‑wired with clues about what it expects and what it returns, so you don’t have to chase down a separate spec.

The same functions also carry built‑in explanations that MCP reads as tool descriptions, saving you from writing separate markdown. On top of that, the code automatically wraps risky calls in try‑except blocks, spits out logs you can follow in real time, and checks inputs before they hit the server. That stack of safeguards matters because it lets you focus on the business logic rather than plumbing.

The next section breaks down exactly what each of those safety nets looks like.

Each tool includes: - Type hints for parameters and return values - Comprehensive docstrings (MCP uses these as tool descriptions) - Error handling with try-except blocks - Logging for debugging and monitoring - Input validation