A book about MCP that you read through MCP. MCP Unlocked is a short, practical guide to building Model Context Protocol servers with the official Python SDK. It ships as a PDF, as markdown, as runnable code, and as an MCP server. Add that server to Claude Code, Cursor, or Claude Desktop and your AI can read every chapter, search the book, and review your own server against it while you work. npx -y mcp-unlocked --license YOUR-KEY That is the whole install. Your license key arrives with your receipt. Written against the protocol as it is now The 2026-07-28 revision of MCP removed the connection handshake and sessions, and the Python SDK moved to a 2.x major. Most tutorials predate both. This edition was written against mcp 2.3.0 and protocol 2026-07-28, and every listing in it was executed before it went in. If a command is in the book, its output is the real output. What is in it What MCP is for: hosts, clients, servers, and the three primitives, with a fourteen-line server you plug into Claude Code Tools: type hints as schema, structured output, and the three different ways a tool can fail Resources and prompts: templates, MIME types, path safety, prompts that carry documents What is on the wire: a raw JSON-RPC exchange, the stateless protocol, stdio and Streamable HTTP A real server: SQLite, lifespan, typed context, progress, and tests with the in-memory client Asking before acting: confirmation without a back-channel, using resolvers On the internet: the 421 wall, workers, bearer tokens, and the attacks the spec names Living with hosts: Claude Code, Claude Desktop, Cursor, VS Code, the Inspector, the Registry, and a troubleshooting table How we got here: five spec revisions in twenty months, what got deprecated, and what to bet on What your AI gets Chapters as resources. All of them, readable by any MCP client. Full-text search. Ask "what does a 421 mean" and get the exact section. Review prompts. Audit your server against the go-live list. Explain any concept the book's way. Plan a new server from the book's patterns. Who it is for Developers who want to give an AI assistant access to something of theirs: a database, an internal service, a pile of documents. You need Python and type hints. You do not need to know anything about MCP yet. What you get The PDF, nine chapters plus a short front matter, about 15,000 words Every chapter as markdown Every code listing, with tests, pinned to mcp 2.3.0 The mcp-unlocked MCP server and a license key that unlocks it Updates to this edition, free One purchase, one reader, any number of your own machines. 30-day refund if it is not for you.