mcp-builder

# MCP Server Development Guide ## Overview To create high-quality MCP (Model Context Protocol) servers that enable LLMs to effectively interact with external services, use this skill. An MCP server provides tools that allow LLMs to access external services and APIs. ## High-Level Workflow Creating a high-quality MCP server involves four main phases: ### Phase 1: Deep Research and Planning #### Agent-Centric Design Principles **Build for Workflows, Not Just API Endpoints:** - Don't simply wrap existing API endpoints - build thoughtful, high-impact workflow tools - Consolidate related operations (e.g., `schedule_event` that both checks availability and creates event) - Focus on tools that enable complete tasks, not just individual API calls **Optimize for Limited Context:** - Agents have constrained context windows - make every token count - Return high-signal information, not exhaustive data dumps - Provide "concise" vs "detailed" response format options - Default to human-readable identifiers over technical codes **Design Actionable Error Messages:** - Error messages should guide agents toward correct usage patterns - Suggest specific next steps: "Try using filter='active_only' to reduce results" - Make errors educational, not just diagnostic #### Study MCP Protocol Documentation **Fetch the latest MCP protocol documentation:** Use WebFetch to load: `https://modelcontextprotocol.io/llms-full.txt` **For Python implementations:** - Python SDK: `https://raw.githubuse...