Create a draft invoice

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

Beyond the annotations it usefully discloses two behaviors: totals are server-computed and the result is an editable draft rather than a payable invoice. However, it says nothing about retry behavior, even though idempotentHint=false while the schema exposes an idempotency_key — an agent could reasonably worry about duplicate invoices and gets no guidance here.

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 short sentences, front-loaded with the action and followed by the mechanics and lifecycle. The only waste is the first line repeating the title verbatim before the more informative second sentence.

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 nested-object mutation tool with no output schema, the description covers the core concept but omits what comes back (draft/invoice id), the currency assumption behind unit_amount, and handling of the split rule. Adequate to start a call, not sufficient to call confidently.

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 38%, so the description needs to carry weight, yet it only restates the taxes basis-point convention (already documented on the 'bps' property) and otherwise lists 'customer, line items, optional taxes'. It adds nothing on due_date, split, metadata, idempotency_key, or the kobo unit of unit_amount.

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 ('Create a draft invoice') and adds the qualifying scope 'draft' versus the later finalized/payable state. Combined with the customer + line items framing, an agent can distinguish it from finalize_invoice, update_invoice and the other invoice siblings without opening the schema.

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?

The sentence 'A draft can be edited; finalize it to make it payable.' gives clear lifecycle context and implicitly routes the agent to finalize_invoice as the follow-up step. It stops short of explicit when-not-to-use guidance (e.g. use update_invoice to modify an existing draft, not this tool).

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