Architectural limitations in Meta's Llama-Prompt-Guard-2-86M and Llama-Guard-3-8B cause them to fail at detecting indirect prompt injections and agentic tool-use attacks, with detection rates dropping as low as 7-37%. Llama-Guard-3-8B enforces strict user/assistant message alternation and lacks support for tool-use roles; attempting to process messages with role: "tool" or role: "ipython" causes the chat template to raise an error, preventing evaluation entirely. PromptGuard 2 operates…
Source: arXiv