Introducing Claude Fable 5: a Mythos-class model that we’ve made safe for general use.
Its capabilities exceed those of any model we’ve ever made generally available.
Claude Fable 5 is our first generally available Mythos-class model.
It ships with new safety classifiers that may flag certain prompts in dual-use domains like cyber and bio.
We've added fallbacks: a refused request retries on Claude Opus 4.8 instead of dead-ending.