US Government Orders Anthropic to Suspend Access to Fable 5 and Mythos 5 Models

Anthropic announced Friday that it has abruptly disabled access to its Fable 5 and Mythos 5 AI models for all customers in order to comply with a U.S. government export control directive invoking national security authorities. The directive required suspension of access by any foreign national, whether inside or outside the United States, leaving Anthropic no choice but to cut off all users to ensure compliance. The government did not provide specific details of its national security concern, but Anthropic said its understanding is that officials believe a method of 'jailbreaking' Fable 5 has been identified. Anthropic disputed the severity of the finding, stating that the demonstrated jailbreak was narrow and non-universal, that the capabilities it exposed are widely available from other publicly deployed models including OpenAI's GPT-5.5, and that no harmful result has been produced. The company said it stands by its 'defense in depth' strategy and argued that applying this recall standard across the industry would effectively halt all new frontier model deployments. This incident follows a separate, ongoing legal dispute in which the Department of Defense labeled Anthropic a supply chain risk earlier this year, a designation Anthropic is challenging in court. Access to all other Anthropic models remains unaffected.