The U.S. Department of Commerce has lifted export restrictions on the Claude Fable 5 and Claude Mythos 5 models. This announcement was made by the Anthropic team on June 30.

We’ve received notice that the Department of Commerce has lifted export controls on Claude Fable 5 and Mythos 5.

We'll begin restoring access tomorrow, and will share an update soon.

We’re grateful to our users for their patience, and to everyone who worked with us on…

— Anthropic (@AnthropicAI) June 30, 2026

The company will make Fable 5 available to users worldwide starting July 1. The model will be accessible via Claude Platform, Claude.ai, Claude Code, and Claude Cowork. Access through AWS, Google Cloud, and Microsoft Foundry will be restored "as soon as possible," according to Anthropic.

Claude Fable 5 will be available again globally tomorrow.

After a series of productive conversations with the US government, we're redeploying the model with a new set of classifiers to target and block more cybersecurity tasks. In the near term, some routine tasks like coding…

— Anthropic (@AnthropicAI) July 1, 2026

“After a series of productive negotiations with the U.S. government, we are resuming the deployment of the model with a new set of classifiers to more accurately identify and block cybersecurity-related tasks. [...] We have also begun developing a consensus framework—together with Amazon, Microsoft, Google, and other Glasswing partners—to assess the severity of AI breaches and determine how AI developers should respond,” the post stated.

Access to Mythos 5 has already been restored for some U.S. organizations following government approval on June 26. The company will continue to collaborate with authorities. According to Anthropic representatives, this will include pre-release access to tools and protective measures for assessment, sharing information about breaches and abuses, and dedicated resources for joint research.

To restore Fable 5, developers trained a new security classifier designed to limit behaviors outlined in Amazon's report to authorities. If a request is blocked, the user will receive a notification, and the request will be redirected to Claude Opus 4.8. The company claims the new classifier identifies specific methods over 99% of the time.

“It is likely impossible to make any AI model completely resistant to jailbreaks,” Anthropic stated.

The company acknowledged that the new measures will lead to more false positives during routine programming and debugging tasks. The team described this as a trade-off for broader access to the model's other capabilities.

Additionally, Anthropic, along with Amazon, Microsoft, Google, and other Project Glasswing partners, has begun developing a unified approach to assess the risks of jailbreaks. The company noted that there is currently no industry-wide standard for determining the severity of such security bypasses.

The proposed framework evaluates jailbreaks based on four criteria:

  • how much it enhances the attacker's capabilities compared to available tools;
  • how many different malicious tasks the bypass affects;
  • how easily it can be turned into a real attack;
  • how simple it is for others to find or replicate this method.

For the most dangerous cases, the company promises to initiate preliminary protective measures immediately upon confirming the severity of the threat. Anthropic is also forming a team for round-the-clock monitoring of channels where jailbreak data is published and launching a HackerOne program for reporting potential Fable 5 security bypasses.

As a reminder, in June, amid restrictions on Anthropic, OpenAI launched the full version of its specialized model for finding, verifying, and fixing vulnerabilities, GPT-5.5-Cyber.

At the end of the month, the company opened limited access to GPT-5.6 Sol, Terra, and Luna for a small group of trusted partners at the request of U.S. authorities.