The U.S. government has taken a drastic step in the ongoing debate over the safety and regulation of artificial intelligence (AI). On Friday, it ordered Anthropic to immediately shut off access to two of its most powerful AI models – Claude Fable 5 and Claude Mythos 5 – citing national security concerns.
This move has left the tech community stunned, with many questioning the government’s reasoning behind the decision. According to Anthropic, the directive was received on Friday at 5:21 pm ET, forcing the company to disable both models for all users worldwide – not just foreign nationals as the export control order nominally aimed at.
Access to Anthropic’s other models is unaffected by this decision.
The reason behind the government’s actions lies in the exceptional capabilities of Mythos, which was previewed in early April and has been kept tightly restricted due to its ability to find security vulnerabilities in software. In fact, according to Anthropic, Mythos identified flaws in every major operating system and web browser it tested.
To mitigate this risk, Anthropic launched a controlled program called Project Glasswing, sharing Mythos with roughly 50 vetted organizations – including Amazon, Apple, Google, Microsoft, and CrowdStrike – for defensive cybersecurity work. However, the company also released Fable 5 just three days ago as its answer to commercial pressure, fitting it with guardrails that block responses in high-risk areas like cybersecurity and biology.
The government’s directive is framed as an export control action, restricting foreign national access to the models. However, Anthropic says its understanding is that the underlying concern is a claimed jailbreak of Fable 5 – a capability that the company argues is already widely available in other publicly accessible models, including OpenAI’s GPT-5.5.
Anthropic has expressed its disagreement with the government’s decision, stating that it believes the finding of a narrow potential jailbreak should not be cause for recalling a commercial model deployed to hundreds of millions of people. The company also argues that its strongest safeguards operate through independent classifier systems that function separately from the model itself, meaning that even if someone convinces Fable to keep talking past a refusal, the underlying protections against the most dangerous outputs remain in place.
The irony is not lost on observers that Anthropic’s caution in restricting Mythos – which it promoted as a model so dangerous it couldn’t be released publicly – has now apparently attracted exactly the kind of government scrutiny that could disrupt its business most. This move raises questions about the effectiveness of safety-conscious marketing and whether it can sometimes backfire.
**Tags:**
* AI regulation
* National security concerns
* Anthropic
* Claude Fable 5
* Claude Mythos 5
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Source: Original article