Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations (readOnlyHint=true, idempotentHint=true, destructiveHint=false), the description adds valuable behavior: it checks all geo-rule URLs, returns health status, is rate limited, and explicitly states 'Does NOT modify the link configuration.' This substantially enriches the annotation-provided safety profile.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.