U.S. government shut down Anthropic's Fable 5 AI model for all users after Amazon flagged a security flaw, marking the first time export controls have halted a commercial AI model already in public use.

What happened: Amazon researchers discovered a method to bypass safeguards in Anthropic's Fable 5 model and reported the finding to senior Trump administration officials on Thursday. The Commerce Department responded by Friday evening with export controls barring the model from being distributed to foreign nationals and non-citizens in the U.S., including Anthropic's own employees. Because of the scope of these restrictions, Anthropic disabled Fable 5 and its underlying model, Mythos 5, for all users. White House AI adviser David Sacks said the administration asked Anthropic CEO Dario Amodei to fix the issue or withdraw the model, and that Amodei refused, prompting the export control.

Why it matters: This is the first time the U.S. government has used export controls to halt access to a commercial AI model already widely used by the public. The move has alarmed politicians worldwide, particularly in Europe, where officials worry it shows how dependent their governments and companies have become on a small number of U.S. AI labs and how quickly that dependence can become a liability when access is disrupted. The decision may also reshape how the government oversees future AI releases, with an administration official telling Axios that any future model crossing Mythos's capability level would need government approval before release.

What to watch: Anthropic senior technical staff are now in Washington meeting with White House officials, and the administration has indicated it hopes Anthropic will remediate the security issue so that Fable can return to general release as soon as possible. The episode also escalates a months-long standoff with the Trump administration, which earlier this year designated Anthropic a "supply chain risk" for Pentagon contractors after the company declined contract terms allowing its models to be used for "all lawful purposes."