The Codex setup start to finish, plus the one setting that decides what it is allowed to touch while you are not watching.
It says ChatGPT on the download page and that is correct: Codex lives inside that app rather than having its own. Sign in with the account you already pay for, then pick Codex from the product menu.
Mac, Windows and Linux are all supported. It is included on every tier, including free.
Make a folder, then in Codex choose New project and select it. Check the name it shows is the folder you meant.
Use a folder you actually work in. An ordinary ChatGPT project only takes uploads; the local one is what reaches files on your machine.
The control sits under the composer. Ask for approval is the default: it reads and edits files in the workspace and runs routine commands, but pauses before touching the internet or going outside that boundary.
Approve for me and Full access do not appear in the menu until you switch them on in Settings, General, Permissions. There is a fourth, Custom (config.toml), for people who want it.
New chat, then the picker. Most people never open it, judge the tool on whatever the default was, and stop there.
On Plus the strongest model is available inside Codex and Work even when it is not in your ordinary chat window.
Turning the feature on is one thing. Deciding which apps it may actually look at is a different screen, and that is the one worth reading slowly.
Your Mac will also want its own yes before anything can watch your screen. Give it the one app the job needs, not everything you happen to have open.
Writing the email and sending the email are two jobs, not one. Say which you wanted, or it will decide for you. Then ask it to check its own work before it reports back.
Most complaints about these tools are really complaints about the brief.
Everything you find yourself explaining twice belongs in a file instead. Codex checks that file first, every single time, so you only say it once. Slash init gives you a starting point so you are not inventing a format.
Treat it like the note you would leave a new starter rather than a config file. Nobody does this on day one, which is why week two often feels the same as week one.
Checked against OpenAI's own documentation on 23 September 2026. Codex is included on every ChatGPT tier, including free.