Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context beyond the annotations: it does not create an order, confirm eligibility, or charge anything, which reassures the agent about lack of side effects. Auth requirements and rate limits are still unmentioned, but are not critical here.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.