Opus 4.8 and gpt constantly hallucinate stuff as well. If you haven’t encountered or caught it that’s something different. Of course these days it’s mostly confidently asserting a wrong thing.

Sometimes the harness can only be a human.

And this is fine. Developing new software with a really smart intern is the same, you, as an expert, need to bring your experience/expertise on the table to have everything right. Because experience needs time.