Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with 1 parameter (0% schema coverage), no annotations, no output schema, and many similar sibling tools, the description is completely inadequate. It doesn't explain the parameter, doesn't differentiate from alternatives, doesn't describe behavior, and doesn't provide any context about what 'description field' means or what the output looks like. This leaves too many gaps for effective tool use.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.