Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With annotations covering safety/mutation hints, a complete input schema, and an output schema, the description supplies the remaining decision-critical context: when to use it, public visibility, privacy handling, authorization, no guaranteed answer, and the private token/inbox workflow. It is complete for an agent to call it correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.