Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as readOnly, idempotent, and non-destructive. The description adds critical behavioral details: data comes from live bakery data (so results may change), sold-out items are omitted from the 'today' lane, and the explicit constraint never to quote items not in a result. These go beyond the annotations and help the agent avoid stale or hallucinated information.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.