Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive behavior, so the safety profile is covered. The description adds genuinely non-obvious behavioral context: the attached widget shows only the source list, not the answer, so the agent must relay the answer text itself. That is practical disclosure beyond the structured fields, though it stops short of describing scoping or result quality behavior.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.