Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is fully covered without prose. The description confirms the return is a set of doc ids and that prefix scoping is optional, which adds a little context, but says nothing about ordering, completeness, or how the prefix is matched.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.