Claude Fable 5 and Mythos 5: Capabilities
Only three days after the release of Claude Fable 5, Anthropic was forced by the United States Government to make it unavailable, when a jailbreak was brought to its attention, rather than the previous situation of ‘yes obviously experts can jailbreak anything if they care enough’ and ‘yes obviously you can ask Fable to fix your code.’
Anthropic cuts off Fable 5 and Mythos 5 access following government order
The US demanded foreign nations be blocked over national security concerns.
The Once And Future Fable #2
On Friday evening the United States Government has forced Anthropic to take down all access to Fable and Mythos.
Anthropic disables access to Fable 5 and Mythos 5 to comply with government directive
Anthropic said it disabled access to its Fable 5 and Mythos 5 models to comply with an export control directive from the U.S. government.
Statement on the US government directive to suspend access to Fable 5 and Mythos 5
The US government has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States.
Anthropic’s Mythos 5 is back
Anthropic’s Mythos 5 model, the subject of weekslong negotiations with the Trump administration, is back in action. No word yet on Fable 5.
More details on Fable 5’s cyber safeguards and our jailbreak framework
What is and isn't blocked by our cyber classifiers, and a first draft of our jailbreak severity framework
Anthropic on Twitter / X
The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.The net effect of…— Anthropic (@AnthropicAI) June 13, 2026
Anthropic says it is disabling Fable 5 and Mythos 5 for all customers after the US government issued an export control order, citing national security concerns
Anthropic: Anthropic says it is disabling Fable 5 and Mythos 5 for all customers after the US government issued an export control order, citing national security concerns
Anthropic releases Claude Fable, a version of Mythos, days after warning AI is becoming too dangerous
Anthropic is releasing Claude Fable 5, its first Mythos-class model available to the public. The model comes with guardrails that block responses in high-risk areas like cybersecurity and biology.
Redeploying Claude Fable 5
Anthropic is redeploying Claude Fable 5 starting July 1 following the lifting of export controls, with updated cybersecurity safeguards and a new industry jailbreak framework.
Trump drops restrictions on Anthropic's Mythos and Fable models | TechCrunch
The Trump administration's erratic approach to AI policymaking has left companies across the industry with little clarity about what will govern future model releases.
Trump administration lifts restrictions on Anthropic's Fable 5
Restoring public access to Anthropic's first Mythos-class model marks the end of weeks-long negotiations.
Claude Mythos #2: Cybersecurity and Project Glasswing
Anthropic is not going to release its new most capable model, Claude Mythos, to the public any time soon.
Anthropic published a jailbreak severity framework — co-developed with Glasswing partners — 3 days after the model it was sanctioned for came back online. The framework is substantive and the ban was likely overblown. Both true. But whoever writes the rubric defines what counts as an incident.
