You wrote a clear rule: maximum 10 guests per booking. Your agent books 15 anyway and reports SUCCESS. To an agent, a rule written in the prompt is a suggestion, not a limit. So check it at the tool layer instead: a small piece of code inspects every tool call before it runs and compares it to your rules. But blocking is only half the answer. Rules that must never bend, like taking payment, you block hard. Limits you steer: the guardrail tells the agent what was wrong and it fixes its own call, so 15 guests becomes 10, the booking goes through, and the user is told what changed. You'll walk away knowing how to enforce a rule the agent can't talk past, and when to block versus steer.

Outline: • The Prompt Engineering Failure • Neurosymbolic Architecture • Live Implementation: Blocking • From Blocking to Steering • Production Patterns and Q&A