Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (destructiveHint=true, idempotentHint=true), the description adds valuable context: it clarifies that no new results will arrive and that previously collected data persists. This explains the nature of the 'destructive' behavior and matches the idempotency hint.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.