Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple read tool with an output schema, full parameter coverage, and safe annotations, the description is complete. It tells the agent what the tool returns (a paper with all paragraphs), the valid ID range, and the optional include_entities flag. Sibling tools are distinguishable.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.