The Myth of Claude Mythos: Small Open Models Replicate Anthropic's Flagship Cybersecurity Claims
Anthropic’s decision to delay Claude Mythos and restrict its preview access rested on a specific argument: Mythos is so capable in cybersecurity contexts that broad deployment would meaningfully increase risk. It was a defensible position in principle, and Anthropic published benchmarks to support it. The problem, emerging from two independent April 2026 studies, is that the same benchmarks look considerably less exceptional when you run smaller, open-weight models against them. ...