U.S. blocks Anthropic's new AI models over security research, disrupting access for hundreds of millions globally—but experts say the research wasn't offensive.

What happened

The Commerce Department used export controls to bar Anthropic from distributing Fable 5 and Mythos 5 to people outside the U.S. and foreign nationals in the U.S., including Anthropic's own non-citizen employees. Because of the directive's scope, Anthropic disabled both models for all users. The government cited research on a 'jailbreak'—an attempt to bypass the models' safeguards—as the trigger.

Why it matters

Anthropic argues that if this standard applied across the industry, it would essentially halt all new model deployments for all frontier model providers. A cybersecurity CEO who reviewed the research told the Wall Street Journal it was actually 'Defense Oriented Prompting,' a technique defenders need—not an offensive hack. The move also raises broader concerns: scholars warn it may discourage AI labs from being transparent with the government about vulnerabilities and could push companies to keep models in-house rather than release them.

What to watch

The directive bars foreign nationals in the U.S. from accessing the new models, a requirement that one think-tank scholar called 'another step on the balkanization of technology.' Anthropic was already deemed a supply-chain risk for Pentagon contractors, and this action appears to worsen relations with the government despite the company's earlier transparency about cybersecurity implications.