Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive, openWorld behavior, so the bar is lower. The description adds genuine return-context: render plus indexed public owner with timestamp, and explicitly bounds scope by saying transfer history is excluded. It stops short of describing freshness/staleness of the indexed owner or failure behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.