List invoices

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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description still adds real context: the newest-first ordering and, importantly, disambiguates the status enum by defining open as 'sent and unpaid' and overdue as 'open and past due', which the schema enum does not explain.

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?

Two tight sentences with the core purpose front-loaded and no filler. It is efficient, though the terseness leaves room to add filtering/pagination context that an agent would need.

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?

An output schema exists, so return values need not be described, and annotations carry the safety profile. However, for a 7-parameter listing tool the description omits any mention of date filters, customer filtering, or pagination behavior, which are central to correct invocation.

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 description coverage is only 43% (only page, after, before are documented), so the description should compensate more. It clarifies the status values, which is genuinely useful, but says nothing about number, per_page, or customer_id filtering, leaving those parameters undocumented in both places.

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 verb and resource ('Lists invoices') and adds the scope detail of ordering ('newest first'). An agent can distinguish it from the singular get_invoice and from list_payments, though it does not explicitly name a sibling to differentiate.

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?

There is no when-to-use guidance, no mention of alternatives like get_invoice for a single invoice or find_customers, and no stated exclusions or prerequisites. Usage is only implied by the verb 'Lists'.

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