Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the tool's safety profile is clear. The description adds that it returns 'historical measurement data with dates and values' and mentions defaults for date parameters, which clarifies the tool's behavior beyond the annotations. No contradiction exists, and the added context (e.g., 'over a date range') enhances understanding without repeating structured metadata.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.