What is and isn't blocked by our cyber classifiers, and a first draft of our jailbreak severity framework
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 on Twitter / X
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
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.
Anthropic cuts off Fable 5 and Mythos 5 access following government order
The US demanded foreign nations be blocked over national security concerns.
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.
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.
Project Glasswing: what Mythos showed us
In recent weeks, we pointed Mythos and other security-focused LLMs at live code across critical parts of our infrastructure. We share what we observed, the models’ strengths and weaknesses, and what the work around them needs to look like before any of it can scale.
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 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
Gemini JiTOR Jailbreak: Unredacted Methodology
How I taught Gemini to build its own euphemisms on the fly, bypass its safety filters, and comply with prompts it would otherwise refuse. Full methodology, now that the specific payload is patched.
How I Bypassed Claude Opus’s CBRN-E Safeguards
A black-box jailbreak using model-authored state steering, plus an outside-in reconstruction of the safeguards it bypasses.
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 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.
