Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, and it does disclose non-trivial data-handling semantics: grouping commas and currency are parsed, and non-numeric rows are excluded and counted. However, it says nothing about error behavior (e.g., a fully non-numeric or missing column), rounding of results, or any safety/permission profile.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.