# What are guardrails in an AI system?

> Guardrails are code checks on what a model responds to, what it can say and what it can do, not rules typed into a prompt.

Source: https://meshin.co/glossary/guardrails
Updated: 2026-10-02

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## Why it comes up

Asking what guardrails a system has is one of the shortest, most common questions in a security review. It is a hard one to answer honestly if the only guardrail is the model's own training and good manners. A board hears it as a proxy for a bigger question. What is the actual worst thing someone could trick this system into doing, and what stands between that action and a real customer?

## What to do about it

Write guardrails as rules the code enforces, not text pasted into a prompt. Test each one against an input designed to defeat it, not a well-behaved example. Put a real check in front of any action that spends money, changes a record, or sends something external. That way a failure blocks the action instead of completing it. The [90-Day Production Sprint](/services/90-day-production-sprint) builds these checks into the workflow itself, not as a retrofit after an incident.