Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
An output schema exists, so return values need no explanation, and with zero parameters the schema burden is minimal. However, for a tool with no annotations, the description omits any behavioral context (read-only nature, scoping, empty-result meaning), leaving it only minimally viable.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.