Anthropic's new Claude Fable 5 is the same base model as Mythos but with guardrails attached

Anthropic has released Claude Fable 5, a safety-restricted "Mythos-class" model intended for general use that falls back to Opus 4.8 for high-risk cybersecurity or biological queries; the company is also rolling out Mythos 5 more broadly. The article outlines Fable 5's safety controls, Anthropic's red-team and bug-bounty testing claims, customer reactions, pricing (higher than Opus 4.8), and the staged rollout plan.