Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (destructiveHint=false, idempotentHint=false), so the description's job is to add what they can't. It discloses the asynchronous queueing model, that routine edits auto-schedule indexing, and that a status check should precede the call — real behavioral context. It stops short of describing throttling, latency, or what the returned job handle looks like, so not a full 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.