Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the closing sentence "Read-only: it never creates, changes or deletes a DNS record" largely restates structured data. It does add one genuine behavioral detail not in the annotations, the result ordering ("oldest first"), which is worth partial credit.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.