Build a tiny MCP server in JavaScript -Claude, Codex friendly (opens in new tab)

TL;DR — Ship a tiny server that exposes tools to LLMs using the Model Context Protocol (MCP). This guide shows a minimal, runnable example, explains each part, and covers common pitfalls (ESM imports, transports, adapters). Why this matters MCP lets models call real tools (fetching data, running commands) instead of hallucinating. It’s a great way to extend models with live data: notifications, GitHub lookups, database queries, etc. What you'll get A working server (index.js) exposing a singl...