Anthropic has shut down access to its Fable 5 and Mythos 5 AI models for all customers after receiving an export control directive from the US government on Friday evening, citing national security concerns. The order, which applied to foreign nationals both inside and outside the United States — and even extended to Anthropic's own employees — left the company with no choice but to cut off access entirely, rather than attempt a complex user-by-user filtering system.
In its official response, Anthropic pushed back on the government's reasoning, stating that officials "did not provide specific details of its national security concern." The company claims that evidence of potential jailbreaks was communicated verbally rather than through formal documentation, and that the vulnerabilities identified were minor issues already present in competing models, including OpenAI's GPT 5.5. Anthropic also noted that it had been cooperating with both US and UK authorities, and had proactively modified its data retention policies to better monitor potential misuse of the models.
Anthropic's statement grew more pointed in its defense, emphasizing that the company "has not even received a disclosure of a concerning non-universal potential jailbreak that led to a harmful result." According to the company, every jailbreak disclosed to them so far has either produced entirely benign responses or represented minor findings that offer no "Mythos-specific uplift" over what other frontier models can already do. This suggests Anthropic believes the government's concerns may be overstated or based on capabilities that aren't unique to its models.
The drastic measure of cutting off all customers — rather than just foreign users — highlights the practical difficulties of complying with sweeping export control orders in a globally connected tech industry. With Fable 5 and Mythos 5 now entirely offline pending further clarification, the episode raises broader questions about how AI companies will navigate national security restrictions when their products are used by researchers, developers, and enterprises across dozens of countries.