I use Opus 4.8 and GPT 5.5 and haven't suffered from hallucinations in months. But we also put a lot of effort into our harness.

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.