Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real behavioral context: pagination via page_token, first-page/onward semantics, and the requirement to pin the token to a single user. It does not describe volume or rate limits, but for a read-only list tool this is adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.