Arcjet Launches Three AI Security Models to Stop Agent Hijacking
San Francisco – November 06, 2026 -- Arcjet released Himalia 1, a prompt injection detection model that scored F1 values of 0.964 and 0.971 on two public datasets, and opened early access to two further models built for coding agents and autonomous security agents.
Three models target different agent environments
Himalia 1 is generally available and is a general-purpose detector for chatbots, AI applications and model endpoints. It flags attempts to override application instructions, extract internal information or manipulate agent behavior.
Thebe 1, for coding agents, is designed to separate legitimate development activity from malicious instructions hidden in tool outputs, web pages and repositories. Arcjet says it is built to cut false positives when agents run commands or touch code.