AgentGuard v0.5.0 Uses AST-Based Taint Tracking to Secure AI Agent Code

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AgentGuard v0.5.0 introduces AST-based taint tracking to detect prompt injection risks in AI agent code written in Python. Unlike regex, which evaluates each line in isolation, the AST approach parses source code into a syntax tree and follows how untrusted data flows across multiple variable assignments before reaching a large language model. The system identifies "sources" of untrusted input, such as request arguments or user messages, and traces taint through method calls, f-strings, string concatenation, and list construction. When tainted data reaches a defined "sink" — such as an OpenAI API call — the tracker raises a finding, while data passed through sanitizers like str() or int() is considered safe and not flagged. The current release supports Python only, with JavaScript and TypeScript support noted as a known gap for future development.

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