Interesting, but I'm not sure the property it attests is one we care about that much. Or rather, it's one you'd expect Anthropic not to tell you it needs to prove. I mean it tells you that you're not being stiffed by Anthropic using a cheaper model and that they haven't literally been MiTMd, but that's kind of table stakes. Otherwise it's not telling you much useful. It's not telling you that your data hasn't been exfiltrated, and it's not telling you any useful property of the answer.

> I mean it tells you that you're not being stiffed by Anthropic using a cheaper model and that they haven't literally been MiTMd, but that's kind of table stakes.

That's literally the most common gripe I see from Anthropic users and, so far from being "table stakes" there no existing mechanism by which those users could verify it is or isn't happening. If Anthropic can figure this out then most of this "is it just me or is Opus hurr durr today" noise can evaporate.