The US government has issued an export control directive requiring Anthropic to suspend all access to Fable 5 and Mythos 5 for any foreign national — including Anthropic’s own foreign employees — citing national security authorities. Anthropic was forced to abruptly disable both models for all customers to ensure compliance, though access to all other Claude models remains unaffected.

Anthropic states the government’s concern stems from a narrow, non-universal jailbreak technique that the company reviewed and found to reveal only minor, previously known vulnerabilities — capabilities Anthropic says are widely available in other publicly-accessible models. The company disagrees with the decision, calling it a misunderstanding, and warns that applying this standard across the industry would essentially halt all new model deployments. Anthropic is working to restore access as soon as possible.

Statement on the US government directive to suspend access to Fable 5 and Mythos 5