Task-led guide · official OpenAI docs checked Nov 3, 2026
How can I use Codex CLI for repeatable coding tasks?
Use codex exec for a narrowly scoped repository task, keep sandbox and approval settings explicit, and validate the result before treating it as automation output.
What is codex exec for?
OpenAI documents `codex exec` as the non-interactive Codex CLI path for tasks such as scripts, CI jobs, and one-off background work. It runs a coding agent against a project. The separate `openai` CLI calls OpenAI APIs; choose it when your script needs direct API operations rather than an agent editing or inspecting a repository.
How should I start a repeatable task?
Choose one bounded job with an observable result, such as addressing a small issue or producing a structured report from a repository. Use a clean branch or disposable checkout, state the permitted files and checks in the prompt, and pin the CLI version in a recurring workflow so upgrades are deliberate. Start with a manually inspected run before scheduling or widening access.
What do sandbox and approval settings control?
Codex documents sandboxing and approval as separate controls. The OpenAI cookbook's repair-loop example uses `--sandbox workspace-write` together with `--ask-for-approval never`; this keeps the run's filesystem scope distinct from whether it pauses for approval. Avoid broadening either setting to make a job pass without understanding the requested access. Keep external network access and credentials limited by the environment that runs the CLI.
Can a script consume structured output?
The Codex CLI supports an output schema and a file for the final message. OpenAI's example writes the result with `--output-schema` and `--output-last-message`. Validate the file and check the process result in your own wrapper; schema-shaped output does not establish that the underlying code change or recommendation is correct.
What should I check before trusting an automated run?
Inspect the complete diff, confirm that only intended paths changed, read the run output, and execute the repository's relevant checks independently. Test the job on a clean branch and include a case where the requested change should not be made. Record the CLI version, model, prompt, sandbox, approval setting, and checks so later runs can be compared on the same basis.
Does this workflow prove Codex is better or safe for unattended changes?
No. The cited documentation describes interfaces and example settings; it does not establish comparative coding quality or guarantee that an unattended run is safe. Treat the procedure as a way to evaluate a bounded task in your own environment, and keep review and repository protections appropriate to the consequence of a change.