Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the transparency burden. 'List' clearly indicates a read-only, non-destructive operation, and the account scope is stated. It does not disclose return format or pagination, but the operation is inherently simple and the description provides the essential behavioral context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.