Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple single-parameter delete tool, the description combined with annotations (destructive, idempotent) and the explicit key parameter is nearly complete. It could mention what happens when deleting a non-existent key, but the idempotentHint already implies no destructive failure, and no output schema is needed for a basic delete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.