Unreleased Anthropic Model 2 (aka Mythos 2) and Mythos 3 and OpenAI Astra Semianalysis reports Model 2 / Mythos 2 is done training and Anthropic are not releasing the model. Anthropic's August 2026 Risk Report describes an unreleased internal model it calls Model 2. It is more capable than Mythos 5, with no current plan to release it externally and the normal external-release evaluation suite not completed. They describe Model 2 as a noticeable improvement on Mythos 5 for internal work. The gain falls short of the earlier leap from Opus 4.6 to Mythos Preview. Other sources say Mythos 3 is currently a reported internal trajectory, not an announced product. Astra is OpenAI next major model. It remains unreleased as of today. On August 1, 2026, an internal version produced new results on ten long-standing open problems in mathematics and theoretical computer science, with Lean certificates published. Six days later OpenAI said it had suspended work on some aspects of Astra after an internal review found it reached the critical cybersecurity threshold"— meaning it could independently identify and carry out attacks against well-protected real-world systems.