US Gov Forces Anthropic to Shut Down Fable 5 & Mythos 5 Immediately

Saleh Megawer

Full Stack Web Developer

2026 Jun 13 253

In a shocking move that sent ripples through the AI industry, the US government issued an official directive compelling Anthropic to immediately suspend access to its two advanced models Fable 5 and Mythos 5, citing national security concerns and export control regulations.

A Sudden Decision With No Warning

Anthropic received the official notice on the evening of Thursday, June 12, 2026, just after 5:00 PM Eastern Time. Under this directive, all foreign nationals are barred from accessing both models — whether inside or outside the United States — including Anthropic's own non-citizen employees.

The company confirmed, however, that the suspension does not affect its other models, and that all remaining services continue to operate normally.

A Security Flaw or an Overreaction?

The government claimed it had identified a method to bypass Fable 5's safeguards. Anthropic, however, reviewed the demonstration provided and found nothing that would justify such a drastic measure. Furthermore, the company noted that the referenced vulnerabilities are minor and already known, and that other publicly available models — including OpenAI's GPT-5.5 — can replicate them without any bypass technique.

Anthropic: Our Strategy Is Sound

The company firmly defended its security approach, explaining that prior to launch, it conducted thousands of hours of red-teaming in collaboration with the US government, the UK's AISI, and multiple independent organizations.

Anthropic also warned that suspending Fable 5 and Mythos 5 over a narrow, non-universal vulnerability would set a dangerous precedent — one that, if applied industry-wide, would effectively halt the release of any new frontier AI model.

Complying While Objecting

While Anthropic confirmed full legal compliance with the directive, it made clear its strong disagreement with the reasoning behind it, stating that the order lacks transparency and proper technical grounding. The company later pledged to release further technical details within 24 hours, and confirmed it is actively working to restore access as soon as possible.