Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses that the presigned URL is short-lived, a useful behavioral detail beyond the annotations that warns the agent not to cache it indefinitely. Annotations already cover readOnlyHint=true, destructiveHint=false, and the 'returns' wording is consistent with them, so no contradiction exists.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.