Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive, not open-world), so the bar is lower. The description adds real behavioral context beyond them: permission-aware scoping, inclusion of onboarding research gathered before external accounts were connected, legacy fields being compact previews, and explicit completeness/indexing state with cursors.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.