Mcp Builder

This walks you through building MCP servers that let LLMs interact with external APIs and services, covering both Python (FastMCP) and TypeScript implementations. The guidance focuses on designing tools for actual agent workflows rather than just wrapping API endpoints. Think consolidating related operations into single high-impact tools, optimizing responses for limited context windows, and writing error messages that guide the LLM toward correct usage. It includes a four-phase approach from research (fetching live MCP protocol docs) through implementation, code review, and creating evaluation tests. The eval framework is smart: questions must be independent, read-only, and require multiple tool calls to answer, which forces you to validate that your server actually enables complex workflows.