Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It discloses the rolling 1-hour window and the specific aggregates, but does not state whether the tool is read-only, potential side effects, or return format. The phrase 'default 1 hour window' hints at configurability contradicted by the empty schema, creating slight confusion.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.