Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a two-parameter, read-only search tool with a fully documented schema, an output schema, and one clearly named sibling, the description is complete. It covers scope, result limits, snippet format, empty-result semantics, language behavior, and the hand-off to `fetch`.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.