Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a paid, open-world, read-but-billed tool with an output schema already present, the description covers scope, returned fields, epistemic caveats, rejection behavior and cost. An agent can decide to call it, form valid input, and interpret results without further clarification.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.