Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does so well: it discloses output field semantics, units (元), sign conventions (main_sell negative), weighted average price fields, historical vs real-time behavior, institutional-only access, and explicit scope exclusions (not order queue, not orderbook).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.