[Feature Request] .codexignore file

[jonasry]

Add support for removing files and path from codex.

Intended use is to prevent files that contain sensitive data from being sent to the AI model. For example test files with sensitive input data for testing.

The .codexignore file is similar to a .gitignore file and contains paths that aren't read/updated by the AI.

[caleb-harrelson]

Also useful for ignoring things like dependency lock files. My pdm.lock is adding ~10k tokens to the context that aren't relevant to codex but I don't want it in .gitignore either.

[amrnali]

Not sure if this can be solved by setting this as an instruction in AGENTS.md. If smn can confirm.

[lostmygithubaccount]

Not sure if this can be solved by setting this as an instruction in AGENTS.md. If smn can confirm.

deterministic solutions are always preferable

[codex-maintainers]

Thank you for the feedback! Please try the latest version of Codex CLI to see if this feature is supported. If not, we encourage you to contribute to the codex-rs/ implementation. More details on our project update can be found here.