Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (one parameter, no output schema), the description provides a solid overview of what the response will contain: messages, delivery summary, escrow status, timestamps, and notification configuration. This equips the agent to understand the tool's output. It falls short of a 5 because it does not mention error behavior, nullability of fields, or whether messages are paginated, which could matter in edge cases.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.