On Friday, June 12, at 5:21 p.m. ET, artificial intelligence firm Anthropic received a letter from the US government directing the company to suspend access to its most capable AI models—Fable 5 and Mythos 5—for any foreign national, including those on Anthropic’s own staff. The order gave no advance notice and no timeline for restoration.
Few institutions had built operational dependence on these specific models: Fable 5 had been public for barely a week, and Mythos 5 was only accessible to a small circle of partners under Anthropic’s Project Glasswing. And on July 1, the US government lifted the suspension, allowing Anthropic to once again make these models available to the world.
But to institutions around the world, the short-lived order revealed how a foreign government could sever access to frontier AI capability overnight, with no warning and no opportunity for an appeal.
The government’s official reason for the suspension was national security concerns. According to Anthropic, the government believed it became aware of a jailbreak technique capable of bypassing Fable 5’s safety controls. Anthropic disputed the severity of the finding, calling it a “misunderstanding” and warning that applying the same standard across the industry would halt frontier model release.
