Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds substantial behavior beyond annotations: it replaces the person's tags, empty tag_ids clears to "No match", group rates and people views recompute immediately, and the override persists so later re-tagging won't re-classify the person. This is exactly the mutation and persistence context an agent needs.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.