Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety and idempotency profile is fully covered structurally. The description adds useful content about what subjects the charts cover (AI adoption, developer trends, model benchmarks, pricing deflation), but says nothing about return format, ordering, or how many charts are actually available for the requested days.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.