Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false), and the description goes further by disclosing that scanned PDF pages are read by an AI vision model, that `ai_accuracy` incurs paid-plan AI processing for every page, and that each call consumes one conversion from a quota. That quota/plan context is genuinely useful behavior an agent cannot infer from annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.