US government orders Anthropic to shut down its new Mythos 5 and Fable 5 AI models over security concerns, forcing the company into emergency negotiations with the Trump administration.

What happened

On Friday, the US government gave Anthropic a 90-minute ultimatum to disable access to Mythos 5 and Fable 5 by any foreign national, citing concerns that a jailbreak method had been discovered in Fable 5's safeguards. CEO Dario Amodei spent the weekend negotiating directly with Treasury Secretary Scott Bessent, Commerce Secretary Howard Lutnick, and National Cyber Director Sean Cairncross, and Anthropic flew key safety and research staff to Washington, DC.

Why it matters

Anthropic had just released these models after weeks of publicity and had positioned them as crucial to the company's recovery from months of clashes with the US Department of Defense. The sudden suspension puts a major US AI company's flagship models on hold and signals the Trump administration is willing to use export controls to restrict AI technology—a sharp shift from its earlier hands-off approach to AI safety.

What to watch

Multiple tech and cybersecurity executives, including Alex Stamos (chief product officer at Corridor), have called for the restrictions on Fable 5 to be repealed, arguing that the safeguards were not uniquely vulnerable and that limiting US AI tools could hand China a competitive advantage. The move has already galvanized international calls for alternatives to American AI systems and prompted companies to sign backup contracts with non-US providers.