Anthropic Launches Claude Fable 5.1 and Mythos 5.1

Anthropic has introduced its latest generation of AI models, Claude Fable 5.1 and Claude Mythos 5.1, expanding its focus on advanced coding, knowledge work and autonomous AI agents.

Anthropic describes Fable 5.1 as its most capable generally available model for complex, long-running tasks. It is designed to work across multiple applications, operate browsers, handle coding projects and complete extended research tasks with less human supervision.

One of the major changes is pricing. Anthropic says cache-read pricing has been significantly reduced, lowering the cost of typical workloads by around 25% and highly agentic workloads by up to approximately 45%.

The company has also strengthened safeguards around cybersecurity and biology. Some requests in sensitive areas can automatically be routed to less capable models, while Mythos 5.1 is being made available to vetted organizations through trusted-access programs.