Codex Setup Guide
Free
Turn a scoped repository task into a reviewed and tested change.
BEGINNER / LOCAL CLI ROUTE
1. Set the stage
This sheet uses Codex CLI. Start with a practice repository, Git checkpoints, and the sign-in method available to your account.
1. Install the CLI
Open the official Codex CLI setup page at learn.chatgpt.com/docs/codex/cli. Select your system tab and use its current install instructions.
2. Open & sign in
Open a terminal in the practice project and run codex. Choose Sign in with ChatGPT or another supported sign-in method when prompted.
3. Set the working rules
Confirm the repository and branch. Add a short AGENTS.md with conventions and checks; inspect /permissions before allowing broader actions.
4. Verify one focused change
Ask for a small edit with acceptance criteria. Review the diff, run the relevant tests, and inspect the actual preview before keeping it.
2. Lean working stack
| Stage | Role | | --- | --- | | Codex | Implement the task | | Git | Keep checkpoints | | Tests | Check the behavior | | Human review | Approve the diff |
Arrows in the visual sheet show the order of work. External connections require separate setup. Optional tools may be replaced with ones you already use. This is a suggested stack for this task, not a universal optimum.
Pick one interface first
The CLI works against local files. Cloud or desktop workflows have different environment setup; do not assume one configures the others.
Keep the toolset small
Use the project's installed build and test tools first. Add a skill or MCP connection only when a named task requires it.
3. First practice task
Inspect this practice app and confirm its folder and branch. Identify the component for the main heading. Propose a small copy change with a precise check; wait before changing unrelated files.
Your setup is working when
The intended files change, checks demonstrate the requested behavior, and the saved Git checkpoint allows the change to be reviewed or reverted.
Troubleshooting
Command not found? Reopen the terminal and check installation. Wrong files? Confirm the working directory. Failed test? Read and resolve the actual failure.
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