Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already signal readOnly/idempotent/non-destructive, but the description adds substantial context: the two-step flow (compact status first, then master status_url), the SSRF host check, and the 'never errors where get_job_status would have succeeded' guarantee. This goes well beyond annotation basics.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.