MCP Builder
DevelopmentGuide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools.
Overview
MCP (Model Context Protocol) servers provide tools that allow LLMs to access external services and APIs. The quality of an MCP server is measured by how well it enables LLMs to accomplish real-world tasks using the tools provided.
This skill guides you through creating production-quality MCP servers in Python (FastMCP) or TypeScript (MCP SDK).
Development Workflow
Phase 1: Deep Research and Planning
- Understand agent-centric design principles
- Study MCP protocol documentation
- Review framework documentation (Python/TypeScript)
- Exhaustively study the target API documentation
Phase 2: Design and Architecture
- Build for workflows, not just API endpoints
- Optimize for limited context windows
- Design actionable error messages
- Follow natural task subdivisions
Phase 3: Implementation
- Choose Python (FastMCP) or TypeScript (MCP SDK)
- Implement tools with proper typing
- Add comprehensive error handling
- Include logging and debugging support
Phase 4: Evaluation and Iteration
- Create realistic evaluation scenarios
- Test with actual agent interactions
- Iterate based on agent feedback
- Optimize token usage and response quality
Key Design Principles
- Build for Workflows: Don't just wrap API endpoints - build thoughtful, high-impact workflow tools
- Optimize for Context: Return high-signal information, not exhaustive data dumps
- Actionable Errors: Error messages should guide agents toward correct usage patterns
- Natural Task Flow: Tool names should reflect how humans think about tasks
- Evaluation-Driven: Let agent feedback drive tool improvements
Supported Frameworks
- Python: FastMCP for rapid development with Python's async capabilities
- TypeScript: Official MCP SDK for Node.js environments