Claude Fable 5: The first Mythos model is powerful, expensive, and heavily filtered
Anthropic has released Claude Fable 5, the first model in its new Mythos class. It leads nearly every benchmark, including SWE-bench Verified at 95 percent, but costs twice as much as Opus 4.8 at 10 or 50 dollars per million tokens.
Strict safety filters block about nine percent of requests, and a new 30-day data retention policy applies even to zero-data-retention contracts.
