You may already pay for a coding agent

A lot of people pay for ChatGPT, use it as a chat window, and never notice the second thing their money buys. Codex is OpenAI’s coding agent. It is included with paid plans, and it does something the chat window cannot: it opens your project and changes the files itself.

What that means in practice

The chat window tells you what to type. Codex types it. You say “the contact form is not sending, fix it”, and it reads the files, finds the problem, makes the change, runs the thing, and tells you what it did. The agent page is the longer version of that difference.

It is the same model (the AI system that writes the replies) you already talk to. The scaffolding around it is what changed.

Two ways in

In the browser. It works on a copy of your project, so nothing on your computer can break. Good first step if you have never used a terminal (a window where you type commands).

In the terminal. It works on your real files, in your real folder, which is faster and more useful once you trust it. The Codex tool page covers the install.

Try it on something safe

Open it in a project you have a backup of, or a duplicate folder, and paste this.

Read this project and tell me, in five lines, what it is and how to run it. Then suggest
one small, safe improvement you could make, and wait for me to say yes before changing
anything.

Say yes to the small change, then check what it did.

One more thing worth knowing. The models behind Codex can be used by other tools too. My scheduled agent calls them, which is why my setup runs on two subscriptions instead of four. My setup shows that wiring.