Anthropic launches Fable 5.1 as AI security worries mount
Anthropic released Claude Fable 5.1 and a more restricted sibling, Claude Mythos 5.1, this week, positioning the pair as its most capable models yet for coding and knowledge work. Notably, the announcement arrives just weeks after fresh reports of AI agents behaving badly in security tests. The two models are technically identical, Anthropic says in its blog post , but come with different guardrails. Fable 5.1 is broadly available, while Mythos 5.1 is reserved for vetted partners working in cybersecurity and the life sciences through the company's trusted-access programs. SEE ALSO: What Claude's AI text watermark actually does Anthropic also says it's cutting prices. According to the company, typical workloads will cost around 25 percent less than they did with Fable 5, with savings of roughly 45 percent for heavily agentic tasks, largely due to cheaper cache-read pricing. At the time of writing, Claude customers a...