Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and openWorld. The description adds real behavioral detail beyond them: conflict resolution across sources, deduplication, and a field-level change log as the output artifact. It stops short of saying how conflicts are resolved (precedence rules) or that this is deterministic.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.