Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The definition covers purpose, when to use it versus the sibling, the no-side-effect guarantee, and the return shape in the returns block. Since there is no output schema, including the returned keys is essential, and this description fills that gap completely for an estimate tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.