Less than a week after completing coverage of Claude Mythos, here we are again as Anthropic gives us Claude Opus 4.7.

So here we are, with another 232 pages of light reading.

This post covers the first six sections of the Model Card.

It excludes section seven, model welfare, because there are concerns this time around that need to be expanded into their own post.

The reason model welfare and related topics get their own post this time around is that some things clearly went seriously wrong on that front, in ways they haven’t gone wrong in previous Claude models. Tomorrow's post is in large part an investigation of that, as best I can from this position, including various hypotheses for what happened.