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Agents is in private beta, so things may change. If you hit a problem, tell us via Support & feedback.
A guardrail is a rule that gets checked every time your Agent runs. It reads what’s going past, decides whether your rule was broken, and either warns you or blocks it. Go to Agents → open an Agent → Build → Guardrails.
Guardrail editor for a PII disclosure policy, with the checkpoint picker, the rule, the Warn action, and the test panel
Guardrails aren’t part of your draft. Each one has its own Save, and saving makes it live right away. There’s no separate Publish step.

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When is a guardrail checked?

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What happens when a guardrail catches something?

Start with Warn so you can see what a rule would catch before it stops anything.

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What guardrails can I start from?

Six ready-made ones come with Hercules: Only two of the six start as Block, so setting these up won’t accidentally stop live conversations.

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How do I write my own guardrail?

Write the rule in plain English, describing what shouldn’t happen. For example:
User input guardrail
Integration input guardrail
Agent output guardrail
Try the rule before you turn it on. In the editor, paste in a message and an Agent reply, click Run check, and you’ll see the verdict it would give in a real conversation.

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Which model should check my guardrail?

Guardrails are checked while someone is waiting, so this is about speed, not raw power: A check that takes too long doesn’t get made, so start on Fast and only move up if things are slipping through.

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Can a guardrail apply to only some integrations?

Yes. An Integration input guardrail starts on All integrations. Change it to pick specific ones.

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Where do I see what was caught?

Open the Violations tab on the Guardrails page. Each one records what was caught, when it was checked, and whether it warned or blocked at the time. Both lists can be filtered and sorted.

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Additional FAQ

Yes. Each one keeps its own history, so you can see how a rule changed over time.
Yes. They’re checked as part of a run, so they add to what the run costs. Keep the list tight.
A guardrail acts during the run and can stop it. A scorer grades afterwards and changes nothing. Use a guardrail to prevent, a scorer to measure.
An old setting that no longer exists. Anything caught while it was around still shows it.