Anthropic's Claude Fable 5: Powerful AI Released, Mythos 5 Held Back

Anthropic has released its most powerful AI model yet, Claude Fable 5, to the public. However, a more advanced version, Claude Mythos 5, is being kept from public access due to safety concerns, with Anthropic describing it as "too dangerous." This restricted version is only available to selected security and critical infrastructure partners. These new models are designed to handle complex tasks over long periods with limited human involvement. Claude Fable 5, built on the same foundation as the restricted Mythos 5, shows major gains in areas like software engineering and scientific research. For example, fintech giant Stripe used the model to complete a code migration of roughly 50 million lines in a single day, a task that would normally take months. The public version, Fable 5, includes aggressive safety controls. If it detects potentially dangerous requests, it automatically switches to an older, more limited model. This release intensifies competition with other AI developers.