Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide the safety profile (read-only, idempotent, non-destructive), so the description need not repeat that. It adds useful context about searchable fields and output shape, though it does not disclose potential limitations like data freshness, pagination, or API-key behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.