Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds context about the document being the authoritative source, which is useful but doesn't disclose additional behavioral traits like return format or potential caveats. The bar is lower due to annotations, and the description meets it without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.