Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnlyHint annotation, the description discloses specific behavior: results are capped at 500 edges, sorted by papers_count DESC, and computed within the window_years window. It also clarifies edge direction semantics ('from' is an input author, 'to' is a co-author). These are valuable operational details not in the annotation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.