Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a single-parameter delete tool with strong annotations (destructive, idempotent) and 100% schema coverage, the description is nearly complete. It explains what, when, and related tools. It could mention that deletion is permanent or what happens if the key does not exist, but those gaps are minor given the simple scope.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.