Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple tool with one optional parameter, the description covers the essential details: range, cost, and randomness. However, it does not specify the return format (e.g., whether it returns an array of strings or a single string when count=1). Given there is no output schema, this omission leaves some ambiguity for the agent.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.