Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish that this is a read-only, idempotent, non-destructive, non-open-world lookup. The description adds meaningful behavioral context beyond the annotations: it identifies The Flowers Directory city pages as the source, notes that phone numbers are only included when listed, provides a last-verified date, and explains that ordering through The Flowers Directory may not involve one of the listed shops. That caveat is especially useful for preventing misuse.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.