OpenAI Codex Mastery Manual: The Complete Guide from Beginner to Power User

Meet OpenAI Codex the right way. This is the complete, plain-English guide that takes you from a curious beginner to a confident, professional user of OpenAI's AI coding agent - with nothing invented and every changing fact checked against the official documentation.You'll learn what Codex really is (and isn't), how the agent loop actually works, and how to drive it from the command line, your editor, and the cloud. You'll write code, debug, test, and refactor; master Git and GitHub without fear; and set up AGENTS.md so Codex follows your rules by default. Then you'll go further - permissions and sandboxing, safe autonomous workflows, subagents and cloud delegation, automation with codex exec, and connecting external tools with MCP.Every concept is taught step by step, in the book's signature style: name the professional term, explain it in plain English, say why it matters, and show the steps. Twelve original diagrams make the big ideas click, and a maintenance chapter teaches you to keep your knowledge current as Codex evolves.Whether you're a complete beginner, a non-programmer, an entrepreneur, or a developer building professional Codex workflows, this manual turns a powerful, fast-moving tool into something you can use with confidence - and safely.