Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It adds 'Returns results sorted by distance,' which is a useful behavioral trait. However, it does not disclose default radius, limit handling, or the meaning of include_small, which could be relevant for agent decision-making.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.