Anthropic announced that, following a U.S. government directive citing national security reasons, it must suspend access to its models Fable 5 and Mythos 5 for anyone considered a “foreign national.” The order arrived on June 12, 2026 and, as an immediate effect, the company disabled those models for all its customers. The rest of Anthropic’s models are not affected.

What happened and how they presented it

The company received the notice the same day at 5:21 pm (ET). The government letter did not include technical details; according to Anthropic’s public communication, the authority believes it identified a method to 'jailbreak' Fable 5.

Anthropic reviewed a demonstration and says the finding shows small, already-known vulnerabilities that other public models can also reproduce without a specific bypass. In short: they found a narrow case, not a universal flaw that wipes out all safeguards.

Anthropic says it is complying with the directive, but disagrees with the measure as disproportionate to what was revealed.