Anthropic restores Fable 5, Mythos 5 access after 18-day US ban

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Anthropic restored public access to its Claude Fable 5 AI model on July 1, after the U.S. Commerce Department fully lifted export controls that had forced both Fable 5 and its sibling model, Mythos 5, offline for 18 days.

For health system CIOs and chief information security officers evaluating frontier AI vendors, the episode is a live case study in AI vendor risk: a federal cybersecurity directive can pull a model’s access with little warning, even for organizations using it defensively.

The AI startup launched Fable 5 and Mythos 5 on June 9 as its first Mythos-class models. The Commerce Department issued the export control directive June 12 after a threat intelligence report from Amazon found a way to bypass Fable 5’s cybersecurity safeguards, prompting Anthropic to suspend both models globally for all users, including its own non-U.S. employees. The department partially eased the restriction June 26, allowing Mythos 5 access for a limited set of vetted organizations, before lifting the controls entirely this week.

Fable 5 is now available on the Claude Platform, Claude.ai, Claude Code and Claude Cowork. Anthropic said it trained an updated safety classifier that blocks the specific bypass technique described in the Amazon report in more than 99% of cases.

Commerce Secretary Howard Lutnick confirmed the decision on social media, saying the department had “worked closely with Anthropic to analyze and approve Fable 5” over the prior two weeks. Anthropic said it is now working with Amazon, Microsoft, Google and other partners on a shared industry framework for scoring AI jailbreak severity, along with expanded pre-release government testing for future frontier models.

At the Becker's 11th Annual IT + Revenue Cycle Conference: The Future of AI & Digital Health, taking place September 14–17 in Chicago, healthcare executives and digital leaders from across the country will come together to explore how AI, interoperability, cybersecurity, and revenue cycle innovation are transforming care delivery, strengthening financial performance, and driving the next era of digital health. Apply for complimentary registration now.

Register to Attend Webinar

The hidden cost of lost clinical time and how leading health systems are responding

Friday, August 7
12:00 PM - 1:00 PM CDT

Presenters: Kassaundra McKnight-Young, Zebra TechnologiesGregory Carras, Zebra TechnologiesJennifer Gene, Levata

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