U.S. orders Anthropic to disable Fable 5 and Mythos 5; daily talks ongoing

Commerce Secretary Howard Lutnick invoked export-control authority on Friday, forcing Anthropic to pull its newest Claude models offline three days after launch over a disputed cybersecurity jailbreak.

The U.S. Commerce Department invoked export-control authority on June 12 to order Anthropic to suspend worldwide distribution of Claude Fable 5 and Mythos 5, taking the company’s newest frontier models offline three days after their June 9 unveiling. The directive, signed by Commerce Secretary Howard Lutnick and addressed to CEO Dario Amodei, cites the risk that the models could be diverted to military intelligence users in China, Russia, or other countries of concern, according to a copy of the letter seen by Reuters.

The mechanics were unusually compressed. A government call landed at Anthropic at 1:00 p.m. ET; the formal directive arrived at 5:21 p.m. ET the same day. Compliance, the company said, required pulling Fable 5 and Mythos 5 for every customer worldwide, including a commercial deployment Anthropic describes as reaching hundreds of millions of people.

What’s notable is how narrow the stated trigger is. The government’s concern, per Anthropic’s statement, is a “potential narrow, non-universal jailbreak” that prompts Fable 5 to read a codebase and patch software flaws. Anthropic says it reviewed the underlying report and found the vulnerabilities surfaced were minor and reproducible using other public models, including OpenAI’s GPT-5.5. Vals AI had rated Fable 5 the most capable public model at release.

Anthropic’s rebuttal lands in two sentences. “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,” the company wrote, adding that the government’s standard “would essentially halt all new model deployments for all frontier model providers.”

Senior Anthropic technical staff have met virtually every day with Commerce since Friday, with an in-person Washington meeting Monday producing no resolution, a person close to the company told Reuters. On Sunday, more than 80 cybersecurity executives, including leaders at Nvidia and Adobe, signed an open letter to Lutnick and National Cyber Director Sean Cairncross urging the restrictions be lifted. Mythos had already been restricted since April to roughly 50 vetted organizations under Project Glasswing, the company’s defensive cybersecurity program.

The backdrop matters. Relations between Anthropic and the administration ruptured earlier this year after the company declined certain U.S. military uses of its models. Export-control authority, designed for chips and weapons systems, is now being aimed at a model weights file, and the loudest objectors are the cybersecurity buyers it was nominally meant to protect.

U.S. orders Anthropic to disable Fable 5 and Mythos 5; daily talks ongoing

Sources