Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnlyHint annotation, the description reveals the ranking algorithm (trust reviews 70%, recency 15%, momentum 10%, views 5%), which is useful behavioral context. It does not contradict the annotations and adds insight into how results are ordered.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.