That’s the default. I didn’t express myself clearly but I thinking your situation is not the common case anymore, or perhaps you are not using it hard enough. Codex limits deplete very fast these days, it’s not “unlimited”.

I am saying that because ChatGPT usage is unlimited, I don't have to eat into my Codex limits when I use ChatGPT. Codex certainly has limits. Last time I had a Claude sub (hedging here since much of the info in my comment was outdated), my usage limits on claude.ai threads was shared with Claude Code.