Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses a filtering guarantee ('manifest-verified'), which tells the agent only validated assets are returned, and 'List' implies a read-only operation. It says nothing about behavior for an incomplete job, empty results, pagination, or auth requirements.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.