Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden and does so well. It discloses the exact statistical outputs (mean, min, max, std, latest value, above/below-average direction), the source (local proprietary dataset), and constraints like lookback_days max of 90 and default of 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.