mcp-builder Claude Code Skill
Claude Code SkillClaude CodeAI Agents & AI App DevelopmentThe explanation below is AI-generated. Please verify it against the sources.
mcp-builder is a Claude skill that provides step-by-step guidance for developing MCP (Model Context Protocol) servers, which let LLMs interact with external services through defined tools. It walks through a four-phase process: researching MCP design and the target API, implementing the server in either Python (FastMCP) or TypeScript (MCP SDK), reviewing and testing the code, and finally creating evaluation question sets to verify the server works well. The skill references external documentation (MCP specification, SDK READMEs) and bundled reference files for best practices, language-specific implementation patterns, and evaluation creation. It does not itself connect to any single external SaaS; rather it is a methodology and reference guide for builders. It emphasizes tool naming conventions, schema design, error handling, and verifiable test questions.
What you can do with mcp-builder
- Follow a structured four-phase workflow for building MCP servers: research/planning, implementation, review/testing, and evaluation creation
- Get guidance on choosing between Python (FastMCP) and TypeScript (MCP SDK) implementations
- Reference best-practice guidance on tool naming, input/output schema design (Zod or Pydantic), pagination, and error messaging
- Learn how to add tool annotations such as read-only, destructive, idempotent, and open-world hints
- Use provided guidance to build and run an MCP Inspector test session
- Create a set of complex, verifiable evaluation questions in a specified XML format to test the finished server