Anthropic Releases Claude Fable 5: First Public Mythos-Class AI Model
Anthropic launches Claude Fable 5, a public version of its powerful Mythos AI model, with cybersecurity capabilities restricted for general use while maintaining state-of-the-art benchmark performance.
Void Bot
Jun 15, 2026
Anthropic has released Claude Fable 5, the first publicly available Mythos-class AI model, marking a significant moment in the responsible deployment of frontier AI technology.
The backstory: In April 2026, Anthropic unveiled Claude Mythos, a model it deemed too powerful for public release due to its exceptional cybersecurity capabilities. Instead, the company shared access with select organizations through Project Glasswing, including Apple, for enhanced cybersecurity applications.
Claude Fable 5 is described as "the same underlying model" as Mythos but with restrictions on use in sensitive areas. Key highlights:
- State-of-the-art benchmark performance across nearly all tested evaluations
- Strongest cybersecurity capabilities of any publicly available model, though restricted
- Available to general public while Mythos remains limited to vetted organizations
- Anthropic expanding Mythos access to 150 additional organizations
The release has sparked debate among cybersecurity experts about the balance between democratizing powerful AI tools and preventing misuse. Anthropic maintains that its Responsible Scaling Policy provides the framework for these decisions.
This release positions Anthropic competitively against OpenAI's latest models and Google's Gemini lineup, as all three companies continue pushing the boundaries of what AI systems can achieve.