Patronus Ark, a local security scanner for AI agents

Reddit r/AI_Agents 08/12/26, 06:25 AM Tools

ai-agents security rust python prompt-injection pii open-source

Summary

Patronus Ark is a new Rust and Python library for locally scanning AI agent text and tool activity, covering prompt injection, PII, data leakage, and tool-related risks without sending data to external APIs.

Hi, we have released a Rust and Python library for scanning the text and tool activity of AI agents. Patronus Ark can inspect user prompts, retrieved documents, tool descriptions, proposed tool calls and the results returned by tools. The scanners cover prompt injection, PII, data leakage, sensitive documents, tool classes, tool actions and security related tool properties. For example, an application can scan a document before adding it to an agent context, scan a tool call before execution and scan the returned tool output before giving it back to the model. Ark only produces classifications. It does not execute or block tools. The application decides whether a result should be allowed, rejected or sent for approval. The core is written in Rust and uses local ONNX models where native detectors are not sufficient. Python bindings are available through PyO3. After downloading the model files, scans run without sending the inspected content to an external API. I am one of the developers and work for the company maintaining the project. The repository is GPL-3.0-only, with a separate commercial license for proprietary distribution.

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