🔍 What you need to know:
- Unprecedented intervention: The U.S. Department of Commerce utilized national security and export control mechanisms to block Anthropic’s new models just three days after their launch.
- Impressive power: The pivot of the crisis is the core of the technology: Claude Mythos 5 is capable of long autonomous tasks, cybersecurity vulnerability discovery at scale, and, furthermore, also features advanced reasoning.
- Marketing side effect: By spending months promoting Mythos 5 as “too dangerous,” Anthropic drew the government’s eyes. The result was an order to bar foreign nationals which, due to logistical and technical unfeasibility, forced the company to completely shut down the models worldwide.
Find out why Anthropic’s Mythos 5 and Fable 5 models were deemed potential threats to U.S. national security.
What seemed to be Anthropic’s greatest breakthrough in artificial intelligence quickly turned into one of the biggest crises ever faced by an AI company. In less than 72 hours, Claude Fable 5 went from a landmark AI launch to being suspended worldwide following intervention by the U.S. government.
The episode placed issues such as national security, AI regulation, technological sovereignty, and the power of American Big Tech at the center of the debate.
The Promise of a Historic Leap in AI
On June 9, Anthropic—a company founded by former OpenAI employees and known for its strong commitment to AI safety—announced Claude Fable 5.
According to the company, it was the most advanced AI model ever released to the public. Fable 5 was based on the highly restricted Claude Mythos 5, a system that Anthropic considered too powerful to be freely released.
Users reported remarkable productivity gains, including:
- Compressing months of programming work into just a few days;
- Migrating massive codebases;
- Executing complex tasks autonomously;
- Advanced reasoning capabilities.
What Was Claude Mythos 5?
Mythos 5 was the true core of the technology. Unlike Fable 5, it featured fewer built-in safeguards and highly restricted access.
Anthropic created a program called Project Glasswing, which gave access to the model to roughly 50 selected organizations.
Among the participants were industry giants such as:
- Amazon
- Apple
- Microsoft
- CrowdStrike
The company said Mythos 5 demonstrated an exceptional ability to identify software vulnerabilities, uncovering flaws in operating systems and web browsers during internal testing.
For that reason, the model was kept away from the general public.
How Fable 5 Came to Be
To compete in the generative AI market, Anthropic adapted Mythos 5 and created Fable 5, a version equipped with additional safety mechanisms.
These protections redirected sensitive queries related to cybersecurity, biology, and chemistry to less powerful models, such as Claude Opus 4.8.
The strategy seemed ideal: deliver an extremely capable AI system to the public without exposing all of the high-risk capabilities.
The Discovery That Changed Everything
Just three days after its launch, the U.S. Department of Commerce said it had identified a technique capable of bypassing some of Fable 5’s safeguards.
According to federal officials, users could gain access to advanced cybersecurity capabilities that had originally been restricted to Mythos 5.
The concern was significant enough that the government invoked export controls tied to national security—measures typically reserved for technologies considered strategically sensitive.
The Global Suspension of the Models
The government directive stated that foreign nationals could not access either Fable 5 or Mythos 5, even while physically present in the United States.
According to Anthropic, complying with the order without shutting down the service entirely was not feasible.
The outcome was dramatic:
- Fable 5 was disabled worldwide;
- Mythos 5 was disabled worldwide;
- Refunds were offered to affected users;
- An official statement expressed regret over the sudden shutdown.
What should have been the biggest product launch in Anthropic’s history became inaccessible overnight.
Sam Altman Criticized Anthropic
The crisis also revived earlier comments from Sam Altman.
Months before the suspension, Altman said the way Anthropic promoted Mythos 5 resembled “fear-based marketing.”
In a sarcastic remark, the OpenAI CEO compared the strategy to someone saying:
“We built a bomb. We were about to drop it on your head. Now we’re going to sell you a bomb shelter.”
Following the government’s intervention, many observers began debating whether Anthropic’s own safety warnings helped convince authorities that the model required extraordinary oversight.
Anthropic’s Defense
Anthropic rejected the government’s decision and said it believed there had been a “technical misunderstanding.”
The company argued that the identified vulnerability was limited and did not allow for a universal bypass of Fable 5’s safeguards.
It also argued that pulling a model used by hundreds of millions of people because of a single potential vulnerability could set a dangerous precedent for the entire AI industry.
A Case That Exposed the Tensions of the AI Era
More than a dispute between a company and the government, the Claude Fable 5 and Claude Mythos 5 episode became a symbol of the tensions defining the new era of artificial intelligence.
On one side are companies seeking to deploy increasingly powerful AI systems. On the other are governments concerned about the impact of these technologies on cybersecurity, defense, critical infrastructure, and national security.
In just three days, a launch that appeared destined to cement Anthropic’s leadership turned into one of the most significant debates ever sparked over the limits of advanced artificial intelligence.
And perhaps the most remarkable part of the story is this: the AI system that its own creator considered too dangerous for unrestricted public release ultimately ended up being taken offline by the government.
Sources and References:
- TechCrunch: Anthropic’s safety warnings may have just backfired: The government has pulled the plug on its most powerful AI
- NBC New York: Anthropic suspends new AI models after government directive
- Fortune: Anthropic disables Fable and Mythos after U.S. export controls flag national security threat
- Anthropic Official: Statement on Fable and Mythos access