Commerce Department orders Anthropic to disable Fable 5 and Mythos 5 worldwide over jailbreak claim

An export-control directive issued Friday at 5:21 p.m. ET bars all foreign nationals from accessing the two models. Anthropic shut them off globally and is disputing the government's evidence.

At 5:21 p.m. ET Friday, Anthropic received a letter from Commerce Secretary Howard Lutnick addressed to chief executive Dario Amodei. It was an emergency export-control directive barring any foreign national from accessing Claude Fable 5 and Claude Mythos 5. Hours later, the company shut both models off worldwide. A U.S. official confirmed the order to Bloomberg; The Wall Street Journal first reported the letter’s origin.

The legal mechanism is an export control, but the practical effect is a global recall of two frontier models four days after launch. Fable 5 went live June 9 as Anthropic’s first “Mythos-class” release, with capabilities the company itself said “exceed those of any model we’ve ever made generally available” and warned that “without safeguards, Fable 5’s capabilities in areas like cybersecurity could be misused to cause serious damage.” Claude Opus 4.8 and the rest of the lineup are unaffected.

Anthropic is disputing the evidence in unusually direct language. The directive, the company says, “did not provide specific details,” and its understanding is that the government was shown “a potential narrow, non-universal jailbreak” suggesting Fable 5 could expose Mythos 5’s cybersecurity behaviors. Anthropic’s own review of the demonstration identified only “a small number of previously known, minor vulnerabilities,” and notes comparable issues can be surfaced on publicly available models including OpenAI’s GPT-5.5.

The company’s pushback is structural. “We disagree that the finding of a narrow potential jailbreak should be cause for recalling a commercial model deployed to hundreds of millions of people,” its statement reads, arguing the implied standard “would essentially halt all new model deployments for all frontier model providers.” To customers, Anthropic is calling the order “a misunderstanding.”

The context is harder to wave off. The Department of Defense previously declared Anthropic a supply-chain risk after negotiations collapsed, and Anthropic is suing the Trump administration to reverse that designation, with litigation ongoing. Pentagon CIO Kirsten Davies posted on X citing “national security and the security of our systems.” Anthropic confidentially filed for a U.S. public listing earlier this month.

The 1980s cryptography export-control fights ended only when the technology became impossible to contain. This dispute is being staged at the same pressure point, between an IPO filing and an open lawsuit.

Commerce Department orders Anthropic to disable Fable 5 and Mythos 5 worldwide over jailbreak claim

Sources