Codex Session Commands

So far, you’ve learned how to use Codex to edit existing files, refactor code, and even generate new ones. Now it’s time to take control of how Codex behaves during your session.

Codex isn’t just a code assistant — it’s also a configurable tool that adapts to your workflow. Through a set of session commands (each starting with a /), you can adjust its model, manage approvals, start new conversations, review your code, and even set project-wide behavior rules.

In this unit, you’ll learn how to use these commands to make your sessions smoother, more organized, and tailored to your development style.

Use the /model command to select which model Codex should use and how much reasoning effort it should apply.

/model

This command is useful when you want Codex to perform differently depending on the complexity of your task. For quick edits or formatting, you might stick with a lighter model. For deeper reasoning — like designing a new architecture or debugging complex logic — you can switch to a more capable one.

After running /model, Codex will display available options so you can choose what best fits your current task.

The /permissions command allows you to decide what Codex can do automatically and what requires your confirmation.

/permissions

By default, Codex asks before applying any change. But if you trust it with certain repetitive tasks — such as fixing imports, formatting code, or updating docstrings — you can approve those automatically.

This keeps your workflow moving faster, while still letting you review more significant changes before they’re applied.

Use the /review command to ask Codex to analyze your current code changes and provide feedback.

/review

This command is especially useful after several edits. Codex will review the updated files, detect potential issues, and suggest improvements. It can point out things like:

• Unused or shadowed variables
• Missing test coverage
• Inefficient logic or redundant code

Think of it as having an instant AI code reviewer available any time you need a second opinion.