Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds value by disclosing the return granularity ("a summary of each account (address, name)") and pointing to where richer fields live, though it says nothing about behavior on an unknown wallet address (empty result vs error).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.