Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a read-only retrieval tool with full parameter schemas, annotations, and an output schema, the description is complete enough: it tells the agent the sources, the verbatim requirement, and the return type. It could have named sibling exclusion conditions, but nothing essential for invoking the tool correctly is missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.