It's not even clear if Anthropic care. If they genuinely think the user is trying to do something dangerous, then "OK, sure, but you're going to have to use Opus 4.8 for that" doesn't make a whole lot of sense.

Maybe this is just Anthropic pre-IPO marketing to try to convince people how much better Mythos is than Opus 4.8. There sure seemed to be a lot of shills out on release day talking about how it was a "step change" (exact phrase) in capability.

In my experience, most models are pretty good at finding security vulnerabilities and fixing them. I can run GLM-5.2, Kimi K2.7, or even a Mistral model, and it'll find issues and propose reasonable fixes.

My impression is that Anthropic's point about Mythos is that it is uniquely good at finding vulnerabilities and then using them to create working exploit chains.