Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (destructiveHint=true, idempotentHint=true, readOnlyHint=false), the description discloses exactly what is mutated (job and credit records), the narrow condition under which the destructive action triggers (queued/running job older than ten minutes), and that the refund happens only once. This is precisely the extra context annotations cannot carry.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.