Anthropic is on the verge of releasing Claude Fable 5—a public adaptation of the Mythos architecture developed under the secretive Project Glasswing. The original Mythos model can autonomously discover zero-day vulnerabilities and execute multi-step cyberattacks. To bring the technology to market safely, Anthropic will split the release: the base Mythos remains exclusive to governments and vetted partners, while Fable 5 becomes a publicly accessible flagship with strict system-level guardrails on network penetration and malicious code execution—while retaining Mythos’s advanced reasoning, ultra-long context, and multi-step autonomous task capabilities. The official announcement is expected on June 10 at the Code with Claude conference in Tokyo.

Code with Claude Tokyo