PromptGuard: an open-source gateway that masks or blocks sensitive prompts to LLMs
New-Caterpillar628 · reddit · 2026-09-29
The author open-sourced PromptGuard, an AI security gateway that prevents sensitive organizational information from reaching external LLMs. It makes ALLOW/MASK/BLOCK decisions before a prompt is sent, combining regex/NER detection, Hindsight agent memory, intent analysis and deterministic risk policies. Notably, it retrieves previously stored organizational context when evaluating each request. Architecture breakdown on Medium, code on GitHub.
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