Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
This is a simple one-parameter tool with an output schema, so the description does not need to explain return values. It covers the core purpose, data source, and default year behavior. It does not explicitly address sibling-tool selection, but that is a usage-guidance gap, not an operational completeness gap.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.