Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's low complexity (1 parameter, no nested objects), rich annotations (readOnly, idempotent, non-destructive), and presence of an output schema (so returns needn't be explained in description), the description is complete. It covers purpose, usage, parameter semantics, and source context adequately for the agent to select and invoke the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.