Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, closed-world, and non-destructive behavior, so the safety profile is covered. The description adds useful scope detail ('between consecutive presentations') and characterizes the diff dimensions, though the output schema already carries the return structure, so this is additive rather than essential.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.