On Friday evening, Anthropic received an export control directive from the US government, citing national security concerns, leading to a complete cutoff in access for Fable 5 and Mythos 5 for all foreign nationals. The company complied with this order, despite not receiving specific details of the national security concern.

In its statement, Anthropic pointed out that any evidence of potential jailbreaks was provided verbally and claimed that these vulnerabilities were minor and available via other models, including GPT 5.5. The company has also taken steps to safeguard Fable and Mythos by working with the US and UK governments and changing its data retention policy.

Anthropic stated: 'We have not even received a disclosure of a concerning non-universal potential jailbreak that led to a harmful result. The potential jailbreaks that have been disclosed to us are either entirely benign responses or are minor findings that provide no Mythos-specific uplift.'

This move raises questions about the balance between innovation and national security, as well as the implications for AI development in an increasingly regulated environment.