Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has no parameters, no annotations, and no output schema, the description does well to specify both the output content (date ranges, contract counts, symbol counts, sector coverage) and the dataset scope ('unusual-activity dataset and its daily aggregates'). It also provides usage context. It is slightly incomplete in not specifying whether the stats are global or per-symbol/time-window, but for a discovery tool this is adequate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.