Why a Developer Chose FastMCP Decorators Over Raw JSON-RPC for an 8-Tool MCP Server

A developer building an MCP server that integrates GitHub and DEV.to APIs faced a key early choice: implement the low-level JSON-RPC protocol manually or use FastMCP's decorator-based API. The low-level approach requires hand-writing JSON Schema blocks, a tool-name dispatcher, and response-wrapping code for every single tool added. With FastMCP, a simple Python decorator and type hints automatically handle schema generation, tool registration, and response formatting, reducing per-tool overhead significantly. The developer documented the decision formally, rejecting the low-level path as unnecessary complexity for a project that simply wraps REST API calls. The article notes that while FastMCP has its own subtle pitfalls, the productivity gains became obvious once the server scaled beyond one or two tools.