Anthropic launches Claude Fable 5.1 and says it’s up to 45 percent cheaper for agentic work

Anthropic has announced the launch of its latest AI models, Fable 5.1 and Mythos 5.1, addressing customer feedback regarding pricing, data retention, and safety guardrails. The company states that Claude Fable 5.1 delivers stronger performance than its predecessor, with costs reduced by approximately 25% for standard tasks and up to 45% for complex agentic tasks, driven by lower pricing on cached data. Early feedback has been positive, with Every CEO Dan Shipper praising the model's coding capabilities, speed, and token efficiency. Box CEO Aaron Levie noted that the model successfully identified subtleties in data that the previous version missed. Regarding safety, Fable 5.1 features more precise safeguards, while Mythos 5.1 maintains existing restrictions on biological queries. Anthropic also detailed its data retention strategy, introducing "Enterprise Frontier Safeguards" that allow for data storage on customer-owned cloud servers to ensure privacy, with a rollout scheduled for later this fall. Claude Fable 5.1 is now available on all platforms, while Mythos 5.1 remains restricted to Project Glasswing participants.