Anthropic releases its first Mythos-class model Claude Fable
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- Anthropic announced Claude Fable 5, its most powerful widely available model, as the first broad release from the Mythos class.
- Claude Fable 5 includes new safeguards that block responses in high‑risk areas such as cybersecurity and biology, enabling public release of a previously deemed too dangerous model.
- Claude Fable 5 falls back to Claude Opus 4.8 for blocked queries, and testing showed 95 % of sessions ran entirely on Fable without fallback.
- Claude Mythos 5 uses the same underlying model as Fable 5 but with lifted safeguards in some areas, currently accessible only through the private Project Glasswing trusted‑access program.
- Pricing for both Fable 5 and Mythos 5 is $10 per million input tokens and $50 per million output tokens, double the rate for Claude Opus 4.8 but half the cost of Mythos Preview.
Why it matters: Enterprises and developers gain access to Anthropic’s most capable model for complex software and vision tasks, while the higher token fees raise operating costs compared with Claude Opus 4.8 and the safeguards block high‑risk domains, limiting use in security‑sensitive applications, though the price remains lower than the Mythos Preview tier.
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