Anthropic unveils Mythos and Fable upgrades amid AI acceleration concerns

Anthropic has released Mythos 5.2 and Fable 5.2, saying both improve coding, reasoning and vision and communicate more clearly. The launch matters because it comes after a report raised the possibility that the company’s internal models are accelerating AI development, while Anthropic says assessing their capabilities remains difficult.

Fable’s input price has fallen from $10 to $8 per million tokens, below that of competitor GPT-6 Astra, and Anthropic says it responds 30% faster; faster serving costs twice as much. Fable 5.2 supports enterprise zero data retention policies, and Anthropic says it has contributed to physics research and formalised Fermat’s Last Theorem. The company says Mythos 5.2 shows stronger covert capabilities in some evaluations than earlier models, but maintains its absolute performance remains low; it did not confirm whether Fable was used in a separate quantum computing proof.