Arcjet Himalia 1 is a general-purpose prompt injection detection model now live for all Arcjet customers. Specialist models Arcjet Thebe 1 for coding agents and Arcjet Carme 1 for autonomous security agents are available in early access. The compact classifiers are fine-tuned from Qwen3-0.6B and return verdicts in milliseconds.
Arcjet Himalia 1 is Arcjet’s general-purpose model for detecting prompt injection in chatbots, AI applications, and model endpoints. Arcjet says it powers prompt-injection detection for SDK calls where that protection is enabled. The model classifies text as benign or injection rather than generating a response; Arcjet describes it as a full fine-tune of Qwen3-0.6B. Detection is used before an application sends a request to its AI provider, so the application can block a request flagged as an injection. The model is part of Arcjet’s broader set of AI security models, which also includes specialist models for coding and autonomous security agents.
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