Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already disclose readOnly, idempotent, and non-destructive behavior, so the description does not need to restate them. It adds useful nuance: the result may be unrelated and should be ignored, and project matching is case-insensitive and returns the most recently updated match. This adds value but no deeper behavioral detail.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.