OpenAI's harness is fully open source[1], and (AFAIK) doesn't come with any kind of signed-build request integrity verification like Claude does. And by that logic, if you're allowed to use their API with a fork of Codex that you yourself compiled, there's nothing stopping you from making some other harness act like such a fork.
And although Codex Desktop is not open source (AFAIK), it does expose CDP and appserver which allowed me to build a Greasemonkey-like plugin system on top of it. It's surprisingly powerful, you can add transcript annotations, programmatically control the side panels, integrate a native-looking account switcher, and so on.
Yup! MIT licensed, do whatever you want, you can also just use it directly with nodejs installed through `npx clankerbend` [0]. The screenshot on the github repo links you to a YouTube demo.
Warning: I use this daily myself for work, but beyond me arguing with it to get the CDP architecture, this was completely vibe-coded. I mostly use vim mode (jump to line, jump to prev/next user message) and the account switcher.
OpenAI's harness is fully open source[1], and (AFAIK) doesn't come with any kind of signed-build request integrity verification like Claude does. And by that logic, if you're allowed to use their API with a fork of Codex that you yourself compiled, there's nothing stopping you from making some other harness act like such a fork.
[1] https://github.com/openai/codex