Claude Fable 5.1 and Claude Mythos 5.1
Why CEREBRO kept it
Claude Fable and Mythos 5.1 release
The text below is an automated extraction of the article at https://www.anthropic.com/claude-fable-and-mythos-5-1, stored verbatim in the public cerebro-vault repository. Copyright remains with the original publisher (anthropic.com).
We’re introducing Claude Fable 5.1 and Claude Mythos 5.1. They’re the world’s most advanced models for coding and knowledge work—and their research capabilities offer an early glimpse of how AI models will contribute to scientific progress. Claude Fable 5.1 and Claude Mythos 5.1 are the same model, but with different levels of safeguards. Fable 5.1 is generally available, while Mythos 5.1 is available only through our trusted access programs; its safeguards are specifically designed to support work in cybersecurity and the life sciences. Alongside its increased capabilities, Fable 5.1 takes im
Community take
Cache reads priced at a quarter cut costs 25-45% for agentic work, but Fable's strict alignment checks keep it unreliable in practice.
Backlinks
Appeared in 1 briefing