Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, covering safety. The description adds meaningful behavioral context: that it returns a synthesized answer and a ranked list with relevance scores, which is beyond the schema. It doesn't discuss rate limits or errors, but this is acceptable given annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.