The U.S. government imposes export controls on Anthropic's Fable 5 and Mythos 5.

According to an official statement from Anthropic, the U.S. government issued an export control directive on June 11 local time, citing national security concerns, and required the suspension of access to Fable 5 and Mythos 5 for all foreign nationals. Anthropic was thus compelled to disable access to both models for all users. The government claimed to have identified a "jailbreak" method that bypasses Fable 5’s safeguards; however, after review, Anthropic stated that the vulnerability is relatively minor and that similar capabilities exist in other publicly available models, such as OpenAI’s GPT-5.5, meaning it does not pose a unique risk specific to Mythos. Anthropic affirmed its commitment to complying with the government directive but strongly opposes removing commercially deployed models—already accessible to hundreds of millions of users—based solely on the discovery of a narrow, isolated jailbreak. The company warned that if this standard were widely adopted across the industry, it would effectively prevent any new deployment of cutting-edge models. Anthropic is currently actively engaging with government authorities to seek the earliest possible restoration of access.