Anthropic Shuts Down Fable 5 and Mythos 5 After U.S. Government Issues National Security Export Control Order

Anthropic has pulled the plug on two of its most powerful AI models. The company disabled access to Fable 5 and Mythos 5 to comply with an export control directive from the U.S. government that cited "national security authorities." The directive arrived at 5:21 p.m. ET on Friday. Both models had launched just three days earlier, on June 9. The directive covers not just people located outside the U.S., but also any foreign national inside the U.S., including Anthropic's own non-citizen employees — leaving the company no choice but to disable the models for all users. Officials told Anthropic the decision came after the government learned of a technique to bypass Fable 5's safeguards, which were designed to prevent access to the powerful cybersecurity abilities of Mythos, the underlying model on which Fable 5 is built. The letter did not provide specific details of the national security concern. Access to less powerful Claude models, including Claude Opus 4.8, was not affected. This appears to be the first government-forced takedown of a publicly deployed frontier AI model.