Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a one-parameter tool with no output schema, the description covers the operation and its most surprising side effect, which is a reasonable baseline. The gaps—irreversibility, expected response, and the fate of other app-scoped resources (test IDs, OTP secrets, simulation configs)—matter more precisely because there are no annotations to backstop the agent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.