Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate write operation (readOnlyHint=false) and non-destructive (destructiveHint=false). The description adds that the contact is created on an existing account, implying validation but no further behavioral details like side effects or permissions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.