This is a comprehensive guide for building MCP servers that let LLMs interact with external APIs and services. It walks you through a four phase process starting with deep research into agent centric design principles (like building for workflows instead of just wrapping endpoints), studying the MCP protocol docs, then implementing tools systematically in either Python with FastMCP or TypeScript with the MCP SDK. The standout bit is the emphasis on designing for limited context windows and writing error messages that actually help agents figure out what to do next. It includes specific best practices for input validation with Pydantic or Zod, response formatting, and pagination handling.
npx skills add https://github.com/mrgoonie/claudekit-skills --skill mcp-builder