Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden for behavioral disclosure. 'Lists' implies a read-only operation, which is reasonably self-evident, but it doesn't explicitly state that it doesn't modify anything or clarify the return format (e.g., names only, categories). For a simple query tool, this is adequate but not rich.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.