Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description reinforces and extends this with valuable specifics: the operation is free, repeatable, does not refresh/re-evaluate/extend evidence, and missing/expired/mismatched credentials fail without modifying the manifest. This adds meaningful behavioral context beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.