Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given moderate complexity, full schema coverage, the output schema, and the idempotency annotation, the description is complete: it identifies the actor, the prerequisite question source, the effect of recording progress, and the returned information. No critical gap remains for correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.