Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the read-only, idempotent, non-destructive safety profile, so the bar is lower. The description still adds real context beyond them: the required tickets:read scope and the note that 'unclassified' surfaces legacy unset projects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.