Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has an output schema, return values need not be explained. The description covers the key aspects of usage (partial updates, null clearing). It lacks explicit prerequisites or permissions, but the annotations and context (readOnlyHint=false, idempotentHint=true) provide sufficient cues.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.