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 with annotations covering destructiveness and idempotence, the description is adequate. It covers purpose, usage timing, and relationship to siblings. It could mention behavior on missing keys or explicit irreversibility, but annotations already hint at these, so it is nearly complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.