Anthropic has disabled access to its Fable 5 and Mythos 5 AI models after receiving a U.S. government directive citing national security authorities. The company said the move affects all users, while other Anthropic models remain available.

Anthropic Suspends Access to Two Advanced AI Models

Anthropic has announced that it is removing access to its Fable 5 and Mythos 5 artificial intelligence models following a directive from the United States government.

In a statement released on June 12, 2026, the AI company said the U.S. government, citing national security authorities, issued an export control directive requiring the suspension of access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States.

Anthropic said the directive also applies to foreign national employees of the company.

According to Anthropic, the practical effect of the order is that the company must disable Fable 5 and Mythos 5 for all customers to ensure compliance. The company clarified that access to all other Anthropic models will not be affected.

Government Cited National Security Concerns

Anthropic said it received the directive at 5:21 p.m. Eastern Time on June 12. The company said the letter from the government did not provide specific details about the national security concern.

However, Anthropic said it understands that the concern may be related to a possible method of bypassing, or “jailbreaking,” Fable 5.

A jailbreak in AI systems refers to a technique that attempts to bypass a model’s built-in safety restrictions. In this case, Anthropic said the reported technique appeared to involve asking the model to inspect a specific codebase and identify or fix software flaws.

Anthropic said it reviewed a demonstration of the technique and found that it identified only a small number of previously known and minor vulnerabilities.

Anthropic Disagrees With the Directive

While Anthropic said it is complying with the government’s legal directive, the company also said it disagrees with the action.

The company argued that the reported issue appears to be narrow and non-universal. Anthropic said it has not received evidence of a universal jailbreak that can broadly bypass the model’s safeguards across a wide range of cyber capabilities.

Anthropic also said that other publicly available AI models are capable of finding similar vulnerabilities without requiring a bypass.

According to the company, using this type of narrow finding as the basis for recalling a commercial AI model could set a standard that may affect future frontier model deployments across the industry.

What Are Fable 5 and Mythos 5?

Fable 5 and Mythos 5 are among Anthropic’s advanced AI models.

Fable 5 was positioned as a powerful model with safeguards designed to reduce the risk of misuse, including in cybersecurity-related tasks. Mythos 5, according to Anthropic’s earlier materials, is a more restricted model intended for a smaller group of trusted users, including cyberdefenders and infrastructure providers.

Anthropic said it had conducted extensive red-team testing for Fable 5 before launch, including work with government, private, and internal teams.

The company said it stands by its “defense in depth” approach, which combines safeguards, monitoring, and data retention policies to detect and reduce possible misuse.

Other Anthropic Models Remain Available

Anthropic emphasized that the suspension applies only to Fable 5 and Mythos 5.

The company said customers should still have access to its other models. It also apologized for the disruption and said it believes the issue is a misunderstanding.

Anthropic said it is working to restore access as soon as possible.

Why This Matters

The move highlights the growing tension between AI companies and government regulators over how powerful artificial intelligence systems should be controlled.

As AI models become more capable, governments are increasingly looking at whether access to certain systems should be restricted on national security grounds. This latest action also raises questions about how export controls may be applied not only to AI chips and hardware, but also to access to AI models themselves.

For customers and developers using Anthropic’s most advanced systems, the immediate impact is clear: Fable 5 and Mythos 5 access has been suspended, and there is no confirmed timeline yet for when access may return.

Source: Anthropic, Reuters, Business Insider