Large Language Model (LLM) guardrails are essential controls that improve the safety, reliability, and governance of generative AI systems. They operate across input, processing, retrieval, tool use, and output layers to detect harmful prompts, prevent data leakage, reduce hallucinations, enforce policy compliance, and control unsafe model behavior. Effective guardrails combine prompt validation, content filtering, role-based access controls, grounding checks, output moderation, PII detection, policy enforcement, and continuous monitoring.