Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, the description explains the key return data points ('is it up, does it have TLS, what's the title?'), which is the core output an agent needs. It also includes cost and use-context. It doesn't describe return formatting or failure modes, but for a one-parameter, low-complexity tool this is essentially complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.