Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With annotations already marking readOnlyHint=true and destructiveHint=false, the description adds valuable behavioral context: the R-value interpretation (R < 1.0 vs ≥ 1.0), concrete return items (R trajectory, spread map, superspreader nodes, containment forecast, AI briefing), and a prerequisite call. This goes far beyond the structured annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.