Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds a real behavioral trait not in the annotations — 'Uses metered access when findings exist' — which tells the agent about cost incurred on results. It does not add return-format or rate-limit detail, but the output schema covers returns, so a 4 is warranted.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.