Claude Mythos: An Updated Review — From Leaked Draft to Project Glasswing April 8, 2026 Abstract Ten days after Anthropic accidentally exposed its next-generation AI model through a CMS misconfiguration, the company formalized what the leak revealed: on April 7, 2026, Anthropic officially announced Claude Mythos Preview and launched Project Glasswing, a cybersecurity initiative giving 40 carefully vetted organizations exclusive access to the model. This review synthesizes all information available as of April 8, 2026 — integrating the original March 26 leak findings with the confirmed benchmark data, partner details, pricing, and safety assessment released at official launch.

Claude Mythos & Capybara: A Comprehensive Research Report Research compiled 2026-03-28 Abstract On March 26–27, 2026, Anthropic accidentally exposed approximately 3,000 unpublished internal assets through a misconfigured content management system, inadvertently revealing the existence of its next-generation AI model: Claude Mythos. The model operates under a new tier designation called Capybara — the first tier above Opus in Anthropic’s product hierarchy. Anthropic has confirmed the leak and acknowledged that Mythos has completed training, describing it as “by far the most powerful AI model we’ve ever developed” and a genuine “step change” in AI capability.