Yeah I've been arriving at the same thing. The other models give me way more usage but they don't seem to have enough common sense to be worth using as the main driver.

If I can have Claude write up the plan, and the other models actually execute it, I'd get the best of both worlds.

(Amusingly, I think Codex tolerates being invoked by Claude (de facto tolerated ToS violation), but not the other way around.)

I don't think there's any ToS violation involved? AIUI you can use GPT models with any harness, at least at present.

You could nonetheless have Codex write up the plan to an .md file for Claude (perhaps Sonnet or even Haiku?) to execute.