Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the complexity (5 parameters, 3 required, financial data context), complete lack of annotations, and absence of an output schema, the description is woefully incomplete. 'Fetch midprice' provides no guidance on parameter usage, behavioral characteristics, return format, or differentiation from similar tools. For a tool in this context, the description fails to provide the minimal information needed for effective use.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.