Arcjet

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.

San Francisco – – September 20, 2026 -- Arcjet has launched agent runtime security, a new product designed to give engineering and security teams visibility and control over AI agents operating inside production systems. The platform targets agents that read and write to databases, process refunds, call APIs, and take autonomous actions across multiple systems on behalf of users.

Arcjet builds its product around three functions: observe, enforce, and audit

The observe layer lets teams ingest agent activity without changing application code, using existing OpenTelemetry tooling or, for Claude users, the Claude Compliance API. Arcjet connects actions across sessions into a single workflow view, capturing prompts, tool call parameters, session metadata, identity, and security decisions, and maintains an inventory of agents and applications running in a given environment.