Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a list-triggers tool with no parameters and no output schema, the description covers the main purpose but doesn't mention any additional context like ordering, filtering (it says 'all' implies no filtering), or whether it includes only user-defined triggers or system triggers. Slight ambiguity, but given simplicity, it's adequate. Not complete as it doesn't specify if it's read-only, but again, no annotations. I'd say 3.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.