Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description still adds real context beyond them: results are limited to direct-stay reviews (not third-party channels) and ordered newest first, which affects how an agent should present results.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.