Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is clear. The description adds only that it returns a count by numeric user_id, which is already in the schema, but does not disclose error behavior or edge cases (e.g., invalid user_id).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.