Related posts
Andrej Karpathy x.com
This is a super exciting release - Claude Fable 5 is the same underlying model as Mythos but with added safeguards. The benchmarks are great and it's SOTA on everything by a margin but I'll add that *qualitatively* also, this is a major-version-bump-deserving step change forward (imo of the same order as Claude 4.5 was in November), peaking especially for long problem-solving sessions on very difficult problems. You can give it a lot more ambitious tasks than what you're used to, the model "gets it" and it will just go, and it's never felt this tempting to stop looking at the code at all (but…
Anthropicbenchmarksqualitatively
The subjects this post names, from the same vocabulary the directory files beliefs under, and the word it uses that this site has seen least often elsewhere. Posts are matched on those words alone — nothing here is a summary of this one.
Nothing else here says these words yet. Try AI, or search the site for it.