At the time of its release Claude Fable 5.1 was, by a healthy margin, the most capable publicly available AI model in the world.

In June, Anthropic first released Fable 5, its Mythos-class AI model for Claude. Three months later, Anthropic is enhancing Claude...

Anthropic has cut a Fable 5.1 cache hit to just $0.25 on input, down from $1.00 for Fable 5. That's also just 2.5% of Fable's normal input-token price of $10, rather than the 10%…

Fable 5.1 is now generally available, while Mythos 5.1 is only available through Anthropic’s “trusted access” programmes.