Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple one-parameter delete tool with good annotations and schema coverage, the description is nearly complete. It covers the operation, usage triggers, and relationship to related tools. It could mention what happens if the key is missing or whether deletion is permanent, but this is minor given the tool's simplicity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.