Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a two-parameter paginated list tool with an output schema, the description covers everything an agent needs: what it returns, ordering, pagination, auth prerequisites, error-avoidance guidance, and which sibling to use instead or in tandem. Return-value detail is correctly left to the output schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.