Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint, destructiveHint=false), so the bar is lower. The description adds genuinely new behavior: the run is asynchronous and must be polled until a terminal status, and it discloses which outputs come back. It omits any rate-limit or timeout guidance, which would have pushed this higher.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.