Researchers have developed Reflex-Guard, a lightweight guardrail for Large Language Models (LLMs) that detects unsafe prompts with low latency. Unlike existing methods, which can add up to 900 ms delay, Reflex-Guard runs locally and uses dense semantic embeddings to filter out harmful content in under 40 ms. The system was tested on a dataset of 30,568 samples and achieved 95.9% recall for detecting harmful prompts. Reflex-Guard is faster than existing solutions like Llama Guard 2 and SafeDecoding, and can detect specific types of attacks with high accuracy. --- Why it matters: This matters to researchers in AI because it provides a more efficient way to prevent language models from being exploited by malicious users. By reducing the latency and improving the accuracy of prompt safety filtering, Reflex-Guard enables real-time applications that require fast responses without compromising data privacy. Source: https://arxiv.org/abs/2608.17556