Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only declare readOnly=false and destructive=false; the description adds real behavioral context on top: legacy status, a Bearer token requirement, the 24-hour team response expectation, and the prerequisite that product_config comes from configure_product. It stops short of describing what happens on validation failure or whether duplicate enquiries are deduplicated.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.