List invoices

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

Annotations already declare read-only, idempotent, non-destructive behavior; the description goes beyond them by explaining caller-driven paging, the termination condition of requesting until fewer than max_results rows return, and that both paid and unpaid invoices appear with the Balance field distinguishing them. No contradiction with annotations exists.

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?

Four sentences, each earning its place: purpose and ordering, usage vs. sibling, read-only safety, paging semantics, and the paid/unpaid distinction. Information is front-loaded, with filtering guidance and safety stated before implementation details.

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?

For a simple two-parameter list endpoint with a rich output schema and strong annotations, every operational need is covered: sorting, when to use vs. search_invoices, pagination termination, and how to interpret paid vs. unpaid rows. Nothing essential is missing.

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% and each parameter already has detailed meaning, including one-based indexing and how to compute the next page. The description adds value by framing the two parameters together as a caller-driven paging strategy and stating the stop condition, which is not fully expressed in the individual parameter descriptions.

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?

The description opens with a specific verb-plus-resource statement, 'List invoices', and immediately adds distinguishing scope: ordering by most recent transaction date and one-page-at-a-time behavior. It also explicitly differentiates itself from search_invoices, so an agent can select the right tool without opening schemas.

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?

It gives an explicit usage condition: use this when there is nothing to filter on for recent billing. It names the alternative, search_invoices, and states the exact condition under which that alternative should be preferred: when filtering by customer, date, or document number. Paging guidance adds further operational clarity.

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