The US government has ordered Anthropic to suspend access to its most advanced AI models, triggering an abrupt shutdown of Fable 5 and Mythos 5 for users worldwide.
Quick Summary – TLDR:
- Anthropic has disabled Fable 5 and Mythos 5 after receiving a US export control directive.
- The government cited national security concerns linked to a potential AI jailbreak.
- Anthropic argues the reported vulnerability was limited and comparable to capabilities already available in other AI models.
- The move marks a significant escalation in US efforts to regulate access to advanced AI systems.
What Happened?
Anthropic announced that it would immediately disable access to its newly launched Fable 5 and Mythos 5 AI models after receiving a directive from the US government. The order requires the company to suspend access to the models for foreign nationals, both inside and outside the United States.
To comply with the directive, Anthropic said it had no choice but to shut down access for all customers, even though it believes the government’s concerns are based on a misunderstanding.
The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.
— Anthropic (@AnthropicAI) June 13, 2026
The net effect of…
US Government Raises Security Concerns
According to Anthropic, the government believes it has identified a method of bypassing, or “jailbreaking,” the safeguards built into Fable 5. These safeguards were designed to prevent the model from assisting with sensitive cybersecurity activities and other high risk tasks.
The company said it reviewed the reported jailbreak technique and found that it only revealed a small number of previously known software vulnerabilities. Anthropic further argued that similar results can be achieved using other publicly available AI systems without requiring any bypass of safety protections.
A US official confirmed that the Commerce Department issued the export control directive, citing national security authorities as the basis for the action.
Why Fable 5 and Mythos 5 Matter?
Anthropic introduced Claude Fable 5 and Mythos 5 as part of a new generation of highly capable AI systems. The company describes Mythos class models as its most advanced technology to date.
The models attracted attention because of their powerful cybersecurity capabilities. Anthropic previously disclosed that Mythos class systems can transform newly disclosed software vulnerabilities into working exploits within hours and, in some cases, minutes.
The company’s internal Red Team warned that such capabilities could dramatically reduce the time required for attackers to weaponize software flaws. Researchers said a single operator could potentially process a month’s worth of security patches in an afternoon, creating new challenges for organizations that rely on traditional patch management schedules.
Because of these risks, Anthropic built extensive guardrails into Fable 5. The company said it spent thousands of hours conducting safety testing with government agencies, independent organizations, and internal security teams before launch.
Anthropic Pushes Back
While complying with the order, Anthropic strongly disagreed with the government’s decision.
The company said no testing effort has uncovered a universal jailbreak capable of broadly bypassing the model’s protections. Instead, the evidence shared with Anthropic allegedly involved a narrow and non universal technique that provided limited results.
Anthropic also stated that perfect jailbreak resistance does not currently exist in the AI industry. According to the company, every major AI system remains vulnerable to certain narrowly tailored attacks, making a layered security approach the most practical solution available today.
The company added that capabilities demonstrated in the reported jailbreak were already available in competing AI models, including OpenAI’s GPT 5.5.
Growing Tensions Between Anthropic and Washington
The latest dispute comes amid a difficult relationship between Anthropic and parts of the US government.
Earlier this year, the Department of Defense reportedly classified Anthropic as a supply chain risk after disagreements over military uses of AI technology. The company has challenged that designation through legal action.
Several reports have also suggested that concerns raised by Amazon and its CEO Andy Jassy may have influenced discussions surrounding the government’s response. Additional reporting indicated that officials were worried the technology could have been accessed by a group linked to China, although details remain unclear.
Meanwhile, David Sacks, co-chair of the US President’s Council of Advisors on Science and Technology, criticized Anthropic’s handling of the issue and claimed the company failed to adequately address concerns raised by a trusted testing partner.
What Happens Next?
Anthropic says it is working with government officials to resolve the issue and restore access to Fable 5 and Mythos 5 as quickly as possible.
The dispute highlights a growing debate over how governments should regulate increasingly powerful AI systems. While Anthropic supports government oversight of unsafe AI deployments, it argues that such decisions should be transparent, technically grounded, and based on clear evidence.
As AI capabilities continue to advance, the outcome of this standoff could influence how future frontier models are evaluated, regulated, and deployed across the industry.
SQ Magazine Takeaway
I think this story is bigger than just Anthropic. It shows how quickly AI has moved from being a technology debate to a national security issue. The fact that the US government was willing to effectively pull access to a newly launched frontier model suggests regulators are becoming far more aggressive. If this decision stands, AI companies may face much higher scrutiny before releasing powerful new systems, especially those with advanced cybersecurity capabilities.
