Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds genuinely useful context beyond that: the quote is signed, valid for only 15 minutes, tax-inclusive and priced in EUR, and non-negotiable, which materially affects how an agent should use it.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.