Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple one-boolean toggle, the description covers what the tool does, the scope (new conversations), how it validates, and a key side effect. Since there is no output schema, that absence is not a gap. It does not explain the exact meaning of 'temporary mode' relative to other modes, but this is likely sufficient for agent selection and invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.