For three years, the artificial intelligence story has been told through a consumer lens. Which chatbot writes better? Which model codes faster? Which company is gaining users? Security entered the narrative occasionally, but usually in the narrow sense of content moderation and model guardrails, the work of keeping a product from embarrassing its maker. That framing shifted in April 2026, when Anthropic's Claude Mythos came into public view. Mythos is, by the available reporting, Anthropic's most advanced restricted-access model: built for high-level reasoning, software engineering, and cybersecurity work.