Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The readOnlyHint annotation already indicates this is a read-only operation. The description adds beyond that by disclosing the exact return structure ({scene_id, scene_name}) and the null-when-none behavior. This is useful context for a simple getter, though it does not need to go deeper given the trivial nature.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.