Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose useful edge-case behavior: grouping commas and currency are handled, and non-numeric rows are excluded and counted. However, it does not mention how missing values are treated or what happens when the column does not contain numeric data.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.