Of course, Opus will also perform relentless self-validation of its own work (it does not bill itself on good looks alone). But remember there’s certainly a higher-than-average credit cost attached to that.

I haven't tried it but I think this can be replicated with a system prompt.

I remember the codex system prompt contains something like, "Do not consider a task complete until you have verified the result."

Although I've been running the new GPT models in a custom harness and they do that anyway now, without being prompted. So I think that prompt was for a previous generation.