The ChatGPT User's Guide to Codex

From Conversation to Creation

By: John Collins

Narrated by: Virtual Voice

OpenAI launched Codex as a desktop app in February 2026. If you're a ChatGPT subscriber, you now have access to something fundamentally different from the conversation tool you know.

ChatGPT talks. Codex does.

Codex is an AI agent that creates documents, processes data, extracts information from messy files, builds spreadsheets, deploys web pages, and organises your work — all while you make coffee. You describe what you want done. Codex goes off and does it.

This handbook is for ChatGPT users who are not software developers. You will not find code tutorials or terminal commands. You will find practical guidance for using Codex to accomplish real work:

• Create formatted PDFs, spreadsheets, Word documents, and presentations from raw data
• Extract structured information from receipts, invoices, contracts, and surveys
• Run multiple AI agents in parallel on different tasks
• Connect Codex to external tools and set up automated workflows
• Write effective instructions that get the results you actually want

The approach throughout is direct and specific. Every capability is illustrated with real task instructions you can adapt. No padding, no filler, no breathless futurism — just what works, how to use it, and where the boundaries are.

Covers the Codex desktop app, GPT-5.3-Codex, the Skills system, local and cloud execution, parallel agents, MCP connections, Automations, and the AGENTS.md file. Includes a Quick Reference guide, glossary of key terms, and a Getting Started checklist.

About the Author: John Collins writes about education, technology, and human development. He is the author of The Claude Cowork Handbook, Teaching After AI, and The Thoughtful Guide to AI for Parents. His work focuses on meeting people where they are — helping them navigate new tools and challenges without assuming technical expertise they don't have.