Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral disclosure burden. It adds useful context by saying results are 'bounded' and 'aggregate' rather than raw or unbounded, and 'Get' implies a read-only operation, but it does not explain what the bound is, what data feeds the stats, or whether any caching or pagination applies.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.