Why You Might Not Be Able To Use Anthropic’s Fable 5
Days after unveiling Fable 5, its latest AI model with Mythos-level capabilities, Anthropic faces a growing dispute that could affect access to some of its most advanced systems. The company announced on Friday that it is disabling access to Fable 5 and Mythos 5 following a US government export control directive that requires the suspension of access for foreign nationals over national security concerns.
The development has raised questions about the future availability of frontier AI models and the extent to which governments may seek to regulate access to advanced AI technologies.
US Directive Forces Suspension
Anthropic said the US government ordered the company to restrict access to the models without providing what it considers an evidence-backed explanation for the concerns. According to the company, officials believe there may be a way to bypass or jailbreak the safety mechanisms built into Fable 5, potentially allowing the model to identify software vulnerabilities.
However, Anthropic disputes the severity of the issue. The company stated that it has only been presented with what it described as verbal evidence of a potential narrow and non-universal jailbreak. Therefore, it does not believe the findings justify withdrawing a commercial AI model that is already available to millions of users.
“The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance. Access to all other Anthropic models will not be affected,” the company said.
Potential Global Impact
The implications of the directive could extend far beyond the United States. Former White House official Dean Ball suggested that the order could prevent all non-Americans, including foreign nationals residing in the US, from accessing Anthropic’s newest models.
As a result, users may be required to verify their citizenship before gaining access. The Indian Express attempted to access Fable 5 from India and found the model marked as “Currently Unavailable” on Anthropic’s Claude interface. While it could not independently verify whether this was directly linked to the government order, the observation appeared consistent with Anthropic’s announcement.
Meanwhile, Anthropic said it believes there has been a misunderstanding and that it is working with authorities to restore access as quickly as possible. In addition, Amazon Web Services confirmed that Anthropic requested the removal of access to Fable 5 and Mythos 5 across all regions to comply with the directive.
A Shift In AI Export Controls
The latest order represents a notable change in US policy. Until now, export controls have largely focused on advanced chips and AI hardware rather than direct access to AI models.
Anthropic argues that if similar measures become widespread, they could significantly slow the deployment of future frontier AI systems across the industry. The company also noted that the directive arrives during an ongoing period of tension with the US government.
Earlier this year, Anthropic reportedly declined to allow its AI technology to be used for domestic surveillance and fully autonomous weapons systems. Following those disagreements, the company was placed on a government supply chain blacklist scheduled to take effect later this year.
Ironically, Anthropic recently called for stronger oversight of advanced AI systems and supported mechanisms designed to block models that present catastrophic risks. Nevertheless, the company maintains that the current directive does not represent fair or evidence-based regulation.
Understanding Fable 5 And Mythos 5
The dispute follows the launch of Claude Fable 5 and Claude Mythos 5. Anthropic introduced the models two months after claiming it had developed an AI system too powerful for broader deployment.
According to the company, both models include safeguards designed to prevent use in sensitive areas such as cybersecurity. Even so, some users have criticised the restrictions as overly broad. Security experts have also warned that highly capable AI systems could accelerate sophisticated cyberattacks if misused.
Claude Mythos 5 uses the same underlying model as Fable 5 but operates with certain safeguards removed. Initially, it is available only to a limited group of trusted users. By contrast, Claude Fable 5 is publicly released with guardrails that block queries related to cybersecurity, biology and chemistry.
Anthropic says Fable 5 is designed for coding, advanced mathematics and visual reasoning. The company also claims the model outperformed other publicly available systems in Vals AI benchmark evaluations and achieved stronger aggregate benchmark results than Claude Opus 4.8. Furthermore, it earned top scores on Cognition’s FrontierCode benchmark while offering improved autonomous performance and greater token efficiency. However, Anthropic notes that the model is twice as expensive as Opus 4.8 and trails some competitors in healthcare and tax-related evaluations.
With inputs from Reuters