Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool read-only, idempotent, and non-destructive, so the safety bar is covered. The description adds that it returns 'public' records (not private) and 'likely' matches (ranked, not guaranteed), which provides some extra behavioral context beyond the annotations. This is modest added value, so a 3 is appropriate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.