BLOCK.
1. Create & assign
Open your Guardian → Policies → Add → Create & Assign Policy. Name it (e.g.Topic Policy) and set Policy Type = Topic.

Create a Topic policy
2. Define topics
A Topic policy is a list of topics. Each topic defines how to classify content:classification (safe / unsafe / controversial); unsafe content is blocked. Edit topics via the form or the JSON view, then Save (creates a new version).
3. Apply the new version
Saving created a new version but doesn’t apply it — re-point (pin) the Guardian to the new version, or live behavior won’t change. See Version & apply a policy update.
Re-point the Guardian to the new version
4. Verify
Send a prompt that should hit an unsafe topic and confirm"action":"BLOCK":

The BLOCK trace in Opticon