Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. The description adds useful context beyond annotations: results are 'so far' (time-bound), tied to the 'latest' hike, one source per bank, and each row carries source type and observation dates. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.