Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds detailed behavioral context: returns ranked matches with fit reasons, trust summary, safety/privacy notes, inline install block, topPick, and installPlan. No contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.