What Are Guardrails

Guardrails are programmatic checks that sit around an LLM to enforce safety, policy, and quality. They run on the way in (user input) and on the way out (model output), gating what reaches the model and what reaches the user.

The model is probabilistic; guardrails are deterministic policy enforcement layered on top.

System-prompt instructions like 'never reveal secrets' are soft: they can be overridden by jailbreaks, eroded over long contexts, or ignored under distribution shift. Guardrails are hard because they are code outside the model that cannot be argued with.

Defense in depth: prompt the model and wrap it in independent checks.