Anthropic says Fable 5.1 will cost an estimated 25% less than Fable 5 for typical workloads and up to 45% less for highly agentic work (Rachel Metz/Bloomberg)

Anthropic has launched Claude Fable 5.1 as a general-availability model and Claude Mythos 5.1 for trusted partners, adding cybersecurity and life-sciences safeguards. The company estimates Fable 5.1 will cost roughly 25% less than Fable 5 on typical workloads and up to 45% less on highly agentic tasks, while its new Enterprise Frontier Safeguards let businesses dictate data review, storage, and management.