Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, openWorld=false, non-destructive. The description adds value beyond them: 'Execution: synchronous', 'Task support: forbidden', 'no publication authority', and explicit downstream-orchestration rules about assistantSummary, raw JSON masking, and mention IDs. It does not cover pagination, ordering, or evidence shape, keeping it from a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.