Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful context (per-connection token ownership, a 15-minute receipt link lifetime, invoices not linked in text) but says nothing about result size, pagination, or failure modes.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads what the tool returns and the no-argument invocation before the widget-button caveat. Dense but almost every sentence carries information; the invoice/receipt linking note is slightly convoluted but still earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, and the description compensates by enumerating the return shape (date, status values, invoice total, due date, requested vs actual kg) plus the receipt-link special case. An agent has enough to call it and interpret results without further documentation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, and the description goes beyond the schema by tying ref to 'an order or invoice id from this tool's result' and giving the exact document=receipt + ref=<order id> invocation that yields a 15-minute receipt link. That adds real invocation semantics the schema only hints at.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific resource (order history of a LINE VIP customer) and enumerates what is returned (orders, standalone invoices, statuses, item kg). It clearly rules out chat-registered customers and guests, but never mentions the sibling get_order_history, so an agent has no explicit differentiation cue against the most similar tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete conditions: 'No arguments needed', 'Chat-registered customers cannot list orders here', 'Not for guests', and explains that widget buttons call it with document/ref. The only missing piece is when to choose this over get_order_history.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.