Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral trait beyond that — "transfer completion remains unknown" warns the operation is asynchronous and unverifiable from the response. It says nothing about required permissions, what gets invalidated, or the dry_run escape hatch.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.