Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint=true, and the description repeats 'Read-only'. The description adds useful context about the default 30-day window and the metric categories, but it does not disclose other behavioral aspects like response structure or pagination. Since an output schema exists, the bar is lower, and this provides modest added value.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.