The ChatGPT Desktop Handbook for Chat, Work, and Codex

The ChatGPT you know is only one third of the app.On 9 July 2026, OpenAI merged the standalone Codex desktop app into a unified ChatGPT desktop application with three modes: Chat, Work, and Codex. Same login, same subscription, three different surfaces for three different kinds of work.

This is the practical playbook for using it well. A non-developer's guide to the ChatGPT desktop app, focused on where the real productivity now lives: the ChatGPT Work agent.

Stop prompting. Start delegating.

Chat gives you a response. Work gives you a finished artifact (a spreadsheet, a document, a slide deck, a folder of processed files) produced by an agent that goes off, gathers what it needs, and hands you the result. This book is about the shift from typing prompts to briefing an agent for real projects. No code required.

What's insideThe three modes explained. When to use Chat, Work, and Codex, and why choosing the right mode matters more than any prompt trick.The six-part brief. The framework that turns vague requests into work an AI agent can actually complete. It's the tutorial every ChatGPT Work beginner needs.ChatGPT Work in depth. Setup, first tasks, files and artifacts, iteration, and the four trigger types for scheduled, recurring, and event-driven work.Codex desktop app coverage: a migration guide for newcomers arriving from the pre-merger Codex world, plus AGENTS.md, Skills, plugins, MCP connectors, and the wider agentic ecosystem.Model tier selection. GPT-5.6 Sol, Terra, and Luna, with routing rules and pricing considerations for each tier, plus early coverage of the new GPT-6 Astra flagship from OpenAI.Power features across all modes. Computer use, the built-in browser, image generation, memory, and personalisation.Safety, permissions, and boundaries: what to delegate, what not to, and how to keep control of the tasks that matter.Troubleshooting. Pattern recognition for the problems you'll actually meet, and the discipline that prevents most of them.Who this book is forNon-developers who want an AI agent doing real work: drafting the report, building the model, processing the pile of files, producing the weekly briefing. If you can write a clear brief for a colleague, you can get real work out of ChatGPT Work. Delegate tasks to AI without writing a line of code.

Also for anyone whose Codex desktop app updated to the new ChatGPT app in July and wants a guide to what changed and how to work with it now.

What you'll come away withA clear mental model of the three modes and which one fits which taskThe habit of writing briefs the agent can actually work fromRouting rules for model tier and reasoning effort, for both quality and costA working system for scheduled and recurring delegationThe judgment to know when to delegate, when to review carefully, and when to keep the workWritten September 2026, current with the GPT-6 Astra release. Includes a quick-reference chart mapping tasks to modes and models, a glossary, and a getting-started checklist for your first hour, first week, and first month.

The tools will keep changing. Delegation endures.