Anthropic has released Claude Fable 5.1 and Mythos 5.1, two versions of the same underlying model aimed at longer-running agentic work. "For enterprise buyers, however, the release is about more than another round of benchmark gains," reports VentureBeat. "Anthropic is simultaneously changing the economics of running persistent agents, reducing the cost of cached context by 75%, and introducing a new security architecture called Enterprise Frontier Safeguards, or EFS, designed to let organizations retain monitoring data inside infrastructure they control." From the report: Those changes arrive at a particularly consequential moment. Over the past several weeks, Anthropic and the U.K. AI Secu...