Anthropic has abruptly disabled two of its most capable models, Fable 5 and Mythos 5, for all customers worldwide. The shutdown follows a directive from the US government, delivered on the afternoon of June 12, 2026, that ordered the company to suspend access on national security grounds.
According to Anthropic's public statement, the order arrived at 5:21pm Eastern as an export control directive. It requires that access to Fable 5 and Mythos 5 be cut off for all foreign nationals, both inside and outside the United States, including the company's own foreign employees. To comply, Anthropic took the simplest path available and switched both models off entirely. Every other Anthropic model stays available.
What the government says
The stated reason is a security concern. Officials told Anthropic they had become aware of a method for jailbreaking Fable 5, a way of pushing the model past its safety limits. The directive itself did not spell out the national security details.
Anthropic says it reviewed a demonstration of the technique. By its account the jailbreak was narrow rather than universal, and amounted to asking the model to read a specific codebase and fix any software flaws it found. The exercise surfaced a small number of previously known, minor vulnerabilities. The company notes these are relatively simple and can be found using other widely available models, including OpenAI's GPT-5.5.
Anthropic pushes back
Anthropic is complying with the order, but it does not agree with it. The company argues the standard being applied here is unworkable for the industry as a whole. "If this standard was applied across the industry," it wrote, "we believe it would essentially halt all new model deployments for all frontier model providers."
It defended its safety record, pointing to a defense-in-depth approach that it says makes jailbreaks either very narrow or expensive to pull off, backed by monitoring systems. It said no tester found a universal jailbreak despite extensive red-teaming, and that it received no disclosure of a concerning, non-universal jailbreak that led to a harmful result.
The company was also pointed about how the decision was made, saying the process lacked transparency, fairness, and technical grounding. "This action does not adhere to those principles," it said.
What happens next
For now Fable 5 and Mythos 5 are dark for everyone, with no restoration date given. Anthropic said it would share further details within 24 hours of receiving the directive.
Why it matters
We have spent the past weeks deep in Fable 5, so the timing is hard to ignore. A single government letter, sent on a Friday afternoon, can switch off a frontier model for every user at once. For anyone building on these tools that is the real story: capability is only half the equation, and access is the other half. We will keep following this one closely.