TLDR:
- The US government issued an export control directive ordering Anthropic to suspend all Fable 5 and Mythos 5 access globally.
- Anthropic reviewed the jailbreak report and found the capabilities were already available in models like OpenAI’s GPT-5.5.
- The reported jailbreak involved asking Fable 5 to read a codebase and flag software flaws, with no harmful result disclosed.
- Anthropic warned the recall standard, if applied industry-wide, would effectively halt all frontier AI model deployments.
Anthropic has disabled global access to Fable 5 and Mythos 5 following a US government export control directive.
The order, received at 5:21pm ET, cites national security concerns tied to a reported jailbreak method. All other Anthropic models remain available.
The company says it is complying with the directive while disputing the technical basis for the decision.
Government Directive Targets Reported Jailbreak Method
The US government issued the directive without disclosing specific national security details in writing. Officials communicated verbally that they had learned of a method capable of bypassing Fable 5’s safeguards.
Anthropic reviewed a demonstration of this technique and found it exposed only minor, previously known vulnerabilities.
The company reviewed what it believes is the report behind the government’s decision. Anthropic stated that the level of capability displayed “is widely available from other models, including OpenAI’s GPT-5.5, and is used every day by the defenders who keep systems safe.” That review found no Fable-specific uplift in the findings.
The reported jailbreak essentially involved asking the model to read a codebase and identify software flaws. Anthropic confirmed it “has not even received a disclosure of a concerning non-universal potential jailbreak that led to a harmful result.” The potential jailbreaks disclosed were either entirely benign or classified as minor findings.
The directive requires suspending access for all foreign nationals, including Anthropic employees with foreign national status, both inside and outside the United States. The company said compliance meant disabling the models for all customers to avoid any breach of the order.
Anthropic Disputes the Standard Applied to Commercial Models
Anthropic launched Fable 5 with a defense-in-depth strategy, combining narrow jailbreak resistance with real-time monitoring and mandatory 30-day data retention.
The company acknowledged during launch that “perfect jailbreak resistance is not currently possible for any model provider.”
The 30-day data retention policy was a deliberate trade-off. It drew pushback from customers but allowed Anthropic to detect, study, and respond to jailbreak attempts quickly.
Anthropic described this as making jailbreaks “either narrow or very expensive to produce,” keeping risk levels comparable to other deployed models across the industry.
On the government’s authority to act, Anthropic said it “believes the government should have the ability to block unsafe deployments, as part of a statutory process that is transparent, fair, clear, and grounded in technical facts.” The company argued this directive did not meet those standards.
Anthropic warned that applying this recall standard broadly “would essentially halt all new model deployments for all frontier model providers.”
The company committed to releasing additional technical details within 24 hours and confirmed all other models in its lineup continue to operate without restriction.
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