You have scripts, a website or an integration someone built for you, and every small tweak means waiting on the developer or paying them again. Codex CLI is OpenAI's coding agent: it runs on your own computer, in the terminal, and you ask it for work on your code in plain language.
Who this is NOT for
If you don't have code of your own to maintain, there's nothing here for you: it won't automate your business on its own (look at n8n for that). If you've never opened a terminal, don't start with the CLI: the README itself points you to the desktop app or to Codex Web at chatgpt.com/codex. And if you don't pay for a ChatGPT plan, you're left with an API key, which the README calls additional setup.
Its direct rival is Claude Code. The practical difference is the account: Codex runs on the ChatGPT plan many people already pay for. Watch the naming mix-up: 'Codex' is this local CLI, an editor extension, a desktop app and a cloud agent all at once. Pick which one you want before installing anything. Few projects are this alive: last push today, but with over 18,000 open issues and PRs, so the docs fall behind. And the mistake everyone makes: accepting whatever the agent writes with nobody reviewing it.
Your first step
On Mac or Linux run curl -fsSL https://chatgpt.com/codex/install.sh | sh. Then type codex inside one of your project folders, choose Sign in with ChatGPT and ask it to explain what that code does.
The Codex CLI implementation guide
The project belongs to OpenAI and it is free: the link beside asks for nothing. The guide to set it up without getting lost is ours: step by step, common mistakes and a checklist. Leave your email and we will send it.
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