Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: results are scoped to the acting person, private collections show only their own records, pagination terminates with an empty next_cursor, and field values are user-authored.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.