Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is known. The description adds the unit normalization default (unit=True) and that the result is a symbolic string, which are helpful behavioral details beyond annotations. It does not discuss limitations like variable assumptions or error handling, but these are minor for a pure computation tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.