Choose the right Codex surface
App, CLI, IDE, web, or mobile control
After this, you'll be able to explain when to use the Codex app, CLI, IDE extension, web/cloud, or mobile remote control.
The idea
Codex is not one place. It is one coding agent across several work surfaces. The right first move depends on where the code lives, how much review you need, and whether the task should run locally or in the cloud.
| Ready | Needs work | |
|---|---|---|
| Job fit | The selected surface can access the code | The task is still vague |
| Proof | The selected surface can run or collect the needed proof | The result is assumed |
| Risk | Low | Breaks when the chosen surface cannot see the code or cannot run the proof command |
| Next move | Continue | Clarify first |
Use Ready only when the proof is visible.
Here is the before and after: before, Codex is guessing from a loose request. After, you can explain when to use the Codex app, CLI, IDE extension, web/cloud, or mobile remote control.
Now try it use the exercise prompt on one real repo task. Keep the output small enough to check before you accept the change.
You are ready when the Codex action, boundary, and proof all match the task.
Try it (10 min)
Watch out for
- Starting in cloud when the task depends on local secrets or a local app state.
- Starting in CLI when the task needs visual review and you do not have a browser proof step.
- Starting on mobile before a host is connected and running.
- Treating Codex web, app, IDE, and CLI as separate products with separate instructions.
Paste this into Claude
Pick one coding task you actually need: Task: [name the change] Repo location: [local machine, GitHub, cloud environment, unknown] Review needed: [diff only, browser preview, tests, PR comments, mobile approval] Risk: [low, medium, high] Choose the best Codex surface: app, CLI, IDE extension, web/cloud, or mobile remote control. Give me the reason, the first command or click I should use, and what proof I should require before accepting the work.
What a good response looks like
Use the Codex app. The task touches UI and needs a browser preview plus a staged diff. Start a project thread from the repo, ask for the change, run the dev server, inspect the in-app browser, then stage only the accepted files.
What good looks like
- The selected surface can access the code
- The selected surface can run or collect the needed proof
- The answer names the review step before acceptance
- The answer does not choose every surface at once
When this breaks
- Breaks when the chosen surface cannot see the code or cannot run the proof command.
- Breaks when the task moves to cloud without a prepared environment, so Codex spends the run recreating setup instead of finishing the work.
AI can help with this
Use Codex to help you you can explain when to use the Codex app, CLI, IDE extension, web/cloud, or mobile remote control. Start with the exercise prompt and your real input. Ask for one draft, then check it against this proof: The selected surface can access the code. Accept only the version you can verify yourself.
You can now
You can name the Codex app, CLI, IDE, web, and mobile roles
- You can match a task to one starting surface
- You can name local versus cloud tradeoffs
- You can require proof before accepting a change
Key takeaways
Pick the surface from the task. The right Codex surface is the one that can touch the repo, run the proof, and show you the diff.
- Codex app is strongest when review, worktrees, terminal actions, browser checks, and plugins belong together.
- CLI and IDE are local-first surfaces for repo work close to your editor or terminal.
- Codex web is for delegated cloud work after the environment is ready.
- Mobile remote control is for steering and approving work on a connected host.
Go deeper