Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds the useful detail that output is 'published processing time plus the stage breakdown where available,' disclosing both content and a coverage limitation, but says nothing about data freshness, rate limits, or behavior when stages are missing.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.