Anthropic Launches Fable 5 with Restricted Cybersecurity Capabilities and Mythos 5 Today

According to Anthropic, the company released Fable 5, a specialized variant of its Mythos model with strict safety guardrails that prevent responses to queries in cybersecurity, biological risk, and other sensitive domains. The model showed significant performance improvements in programming and complex system problem-solving across extended timeframes.

Simultaneously, Anthropic released Mythos 5, which retains full cybersecurity capabilities without the aforementioned safety restrictions. Access to Mythos 5 will be limited to a small number of vetted trusted groups through a dedicated initiative called Project Glasswing.