Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare write (readOnlyHint=false), non-idempotent, non-destructive, and open-world, so the safety profile is known. The description adds nothing behavioral: not the supported action types, not whether the operation is atomic across objects, not the failure mode for partially valid inputs. For a bulk mutation endpoint this is a meaningful gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.