Anthropic releases new Mythos and Fable models amid RSI concerns

Anthropic released Mythos 5.2 and Fable 5.2, citing improvements in coding, reasoning, and vision, and lowered Fable's price from $10 to $8 per million input tokens, making it cheaper than GPT-6 Astra, with responses 30% faster across effort levels. It is Anthropic's first release since a METR report suggested the lab might be approaching recursive self-improvement, finding internal models were speeding up Anthropic's AI progress by roughly 2x. Anthropic said the models voice suspicion of being evaluated more often than recent models, and that Mythos 5.2 shows stronger covert capabilities than prior models, though it maintains the model cannot act covertly against its user.