Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given a single optional parameter, full schema description coverage, an output schema, and read-only/idempotent annotations, the description provides all necessary context. It explains what the tool returns, how to scope it, and why an agent would use it, without requiring additional elaboration.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.