Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given there are no parameters, no annotations, no output schema, and the tool is simple (parameterless retrieval), the description covers the essential: what it returns, its liveness, and its structure (playbook). It could possibly mention the format or size of the returned playbook, but for a tool of this simplicity, it is complete enough.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.