Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavior beyond them: the XBRL cash-flow source, newest-first ordering, and the sign convention (negative = cash outflow), which prevents misreading the values.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.