Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds that the result spans the user's whole collection (both note types and decks), but says nothing about return shape, ordering, or how the two resource kinds are combined in one response — a real ambiguity for a tool that returns two entity types.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.