Anthropic launches Fable and Mythos 5.1 with lower costs, fewer false flags
Anthropic released Fable and Mythos 5.1, updated versions of its flagship AI models that cut token costs and reduce false-positive blocks from safety filters. Mythos 5.1 remains restricted to vetted cybersecurity and life sciences partners, while Fable 5.1 is now broadly available via cloud platforms and Anthropic's API. The release also introduces a Zero Data Retention option for Fable through a new Enterprise Frontier Safeguards service arriving in June, letting clients run the model on their own infrastructure while retaining control over misuse monitoring.