Does forking/modifying Codex CLI affect ToS when using “Sign in with ChatGPT”?

[thife455]

Hi! I’m using Codex CLI for personal use via "Sign in with ChatGPT"(ChatGPT subscription, not an API key).

I’d like to fork the Codex CLI repo and add some UX changes (mainly a "plan mode”"/ planning step in the CLI before it starts making edits). The fork would still use the official auth flow (no scraping, no private endpoints), not try to bypass rate limits or restrictions, not do bulk automation/scraping; just normal interactive use, keep licensing notices/attribution (Apache-2.0) if I publish it.

Question: Is a fork like this allowed under OpenAI’s Terms/usage policies when used with “Sign in with ChatGPT”?
If there are guidelines on what kinds of modifications are not OK (e.g., automation patterns that look like programmatic extraction), I’d appreciate pointers.

[etraut-openai]

The codex CLI sources are licensed under a permissive Apache license, and you're welcome to fork the repo and make modifications to suit your own needs.

The Terms of Use for OpenAI's services are covered here.

You mentioned that you would like to add a plan mode. You may be interested to learn about a new "skills" feature that we announced today. You can read about it here. The feature includes a "plan" skill that you can invoke for planning purposes. Please give it a try and let us know what you think.

[thife455]

That's Nice! I will check it out!

Just to narrow this down: the only thing I’m trying to clarify is the ChatGPT subscription / Terms of Use side.

The Terms say you can’t "automatically or programmatically" use/extract from the Services, but tools like Codex CLI are inherently making programmatic requests. Unlike Claude, I haven’t seen an explicit statement that “Sign in with ChatGPT (OAuth)” is an approved way to use a third party service with codex under a ChatGPT plan.

Could you confirm (or point me to the exact doc) that clarifies if using Codex CLI with “Sign in with ChatGPT” is officially permitted under a ChatGPT subscription for personal use, and forking the client and adding a UI/UX feature like plan mode doesn’t change that, as long as it uses the standard login flow, respects rate limits, and doesn’t access undocumented/private endpoints or do bulk scraping?