Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only behavior, but the description adds little beyond the list of metrics. It does not explain how the data is aggregated, whether the overview is limited to a date range, how the client parameter affects the result, or any other behavioral detail. The description is essentially a summary of contents, not behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.