Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile, so the bar for the description is lower. The description adds useful context by defining what 'health' means here — entry counts, type/tier breakdown, and sync backlog — which the tool name alone does not convey. It aligns with the read-only annotation by describing observation rather than mutation, and discloses no side effects, which is appropriate for a read-only tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.