MCP Server Development Guide

Spec status (June 2026): current MCP spec revision is 2025-11-25 (https://modelcontextprotocol.io/specification/2025-11-25). The 2026-07-28 release is at RC w/ stateless protocol core, Extensions framework, Tasks, and MCP Apps — check the changelog before designing session-dependent features. SDKs: mcp (Python) and @modelcontextprotocol/sdk (TS) both remain 1.x.

When to Use

• Building MCP servers for Claude/LLM integration
• Creating tools for external API access
• Python (FastMCP) or Node/TypeScript (MCP SDK)
• Designing agent-friendly tool interfaces
• Optimizing tool responses for context limits

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. The quality of an MCP server is measured by how well it enables LLMs to accomplish real-world tasks using the tools provided.