Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool read-only and non-destructive, so the description only needs to add behavioral value. It does so by listing the returned fields and noting that snippets appear only 'when readable,' which is useful nuance. It does not mention limits or empty-result behavior, but these are minor for a simple search tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.