Anthropic launched Claude Fable 5 today, June 9, 2026. It is the most capable model Anthropic has ever made generally available, and it lands at a price point below half of what Claude Mythos Preview costs. If you build on Claude, or if you are evaluating which frontier model to put at the center of your stack, this release changes the calculus.
Here is everything you need to know, sourced directly from Anthropic's announcement.
What Is Claude Fable 5?
Fable 5 is a Mythos-class model that Anthropic has made safe for general use. The naming tells you the positioning: Fable (from the Latin fabula, "that which is told") and Mythos share the same underlying model. The difference between them is a set of safety classifiers that govern which kinds of requests Fable 5 can fulfill. More on that below.
Mythos-class models sit above Opus in Anthropic's capability hierarchy. Claude Fable 5 is therefore more capable than any Opus model, including Opus 4.8, which until today was the top of the public stack.
