Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, and the description correctly frames this as a pure computation. It adds real behavioral value by specifying that all three representations are returned and by stating the American-odds formatting convention (no commas, e.g. +441 or -200).
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.