It's interesting to see Opus 4.7 follow so soon after the announcement of Mythos, especially given that Anthropic are apparently capacity constrained.

Capacity is shared between model training (pre & post) and inference, so it's hard to see Anthropic deciding that it made sense, while capacity constrained, to train two frontier models at the same time...

I'm guessing that this means that Mythos is not a whole new model separate from Opus 4.6 and 4.7, but is rather based on one of these with additional RL post-training for hacking (security vulnerability exploitation).

The alternative would be that perhaps Mythos is based on a early snapshot of their next major base model, and then presumably that Opus 4.7 is just Opus 4.6 with some additional post-training (as may anyways be the case).