Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full disclosure burden and does: read-only, update cadence tied to disclosure dates with a note that missing periods are not a fault, HK support, and a warning not to hard-parse HK column names against A-share conventions. It also reveals the return shape (three tables in fixed index order, descending by period).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.