Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must carry the behavioral load, and it does disclose real data-handling semantics: grouping commas and currency are normalized, and non-numeric rows are excluded and counted. It still omits what happens if the column is entirely non-numeric, whether errors are raised, and the exact shape of the result.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.