Anthropic has disclosed an unreleased internal AI model that it says is more capable than Claude Mythos 5, according to the company’s August 2026 Risk Report.
The model, referred to only as Model 2, represents a noticeable improvement over Mythos 5 across many tasks relevant to Anthropic’s internal work. The company said the improvement is smaller than the capability jump it previously observed between Claude Opus 4.6 and Mythos Preview.
Anthropic said it does not currently plan to release Model 2 externally and has not completed its full suite of typical predeployment assessments, leaving the company with somewhat lower confidence in its understanding of the model’s capabilities.
Model 2 and Mythos 5 are among Anthropic’s most capable and frequently used internal models. They are used heavily for coding, data generation and other agentic tasks across the company.
Anthropic also revealed that Claude now authors a large majority of the code merged into its production codebases. The company said AI assistance has significantly accelerated its internal research and development efforts, although it does not believe the acceleration has yet reached a factor of two.
