Thank you!

Great point. Indeed my methodology was to treat the prompt refactoring as one-off task, therefore I didn't care much about cost/latency.

As for having GPT-5-mini do the rewriting — that’s a really interesting idea. I think the biggest challenge is avoiding cognitive overload. The Tau² agent policies are pretty complex: it’s easy to grasp the overall task, but the detailed rules for each user case aren’t always obvious.

I'm not sure if how easy it is to actually overload GPT-5-mini, so that's definitely worth exploring.