Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with one parameter, no output schema, and annotations covering idempotency, the description provides adequate operational context. It names the target activity and the graceful-stop behavior, and sibling names clarify the campaign lifecycle. However, it could have mentioned that the operation is safe to call even if already stopped, but that is already covered by the idempotentHint annotation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.