Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It reveals that grouping commas and currency are handled, non-numeric rows are excluded and counted, and it lists the returned statistics. This goes beyond a simple 'compute stats' and provides meaningful context. However, it does not disclose error handling for invalid columns or empty datasets, which prevents a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.