Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, and non-destructive behavior, so the description correctly avoids repeating those. It adds useful context by explaining that the id is an account-relative ordinal, safe to display, and is what other tools expect back. No contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.