Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds valuable behavioral context beyond annotations: it explains the draft status, that orders are not charged initially, and the multi-step workflow (create empty order → add items → confirm). Annotations provide readOnlyHint=false and destructiveHint=false, but the description enriches this with practical implementation details. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.