Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations and no output schema, the description carries the full burden of explaining behavior, but it only restates the resource and temporal aspect. It does not disclose return format, time range, aggregation, or any required context beyond account_id. It adds little beyond what the tool name already communicates.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.