Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false, but the description goes far beyond by disclosing the asynchronous polling model (returns immediately, 1-2 minutes until done, poll get_advanced_seo_report), the refusal condition (already running), the cost (1 AI brain credit, charged upfront, refunded on provider failure), and subscription requirement. It also describes the side effect of storing a report, which is richer than the bare annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.