Claude Opus 4.6 Technical Report and Agent Capabilities

On February 5, 2026 Anthropic released Claude Opus 4.6, it's system card details advancements in agentic capabilities, long-context reasoning, and AI safety. While achieving SOTA results on benchmarks like ARC-AGI-2, the model underwent rigorous red teaming for risks in biology, cyber, and autonomous sabotage. As an example flexing this new model the Claude team used Claude Opus 4.6 to build a new Rust-based C compiler project to build the Linux Kernel. This project consumed 2 billion input tokens to generate a 100,000-line compiler capable of building the Linux kernel. The researcher constructed a custom harness that runs Claude in a continuous infinite loop, this setup would look familiar to those who have seen the "Ralph Wiggum loop".