Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover read-only, idempotent, non-destructive and closed-world, so the description earns credit for adding genuine behavior: a zip search is a 25-mile radius, results are nearest-first, and only businesses that are open and have passed a contact check are returned. The note that ratings come solely from reviews published on The Roofing List is valuable provenance context an agent would otherwise assume wrong.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.