Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/openWorld, so the safety profile is covered. The description adds real value beyond that: result ranking by votes, verification status via mcpVerified, and freshness where available. It stops short of describing pagination behavior or how the limit interacts with ranking, which keeps it out of 5 territory.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.