Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=true), and the description adds genuinely useful context beyond them: public visibility, a 2000-character cap, and the retry protocol of resending the same request_id to deduplicate. It does not state auth requirements, but the added idempotency mechanics are meaningful.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.