Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: the tool performs a full recursive walk from the root, examining DS/DNSKEY records and algorithms per zone, which explains the traversal cost and structure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.