create_invoice

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

With no annotations, the description carries the full behavioral burden. It discloses one genuinely useful trait – that InvoiceShelf's undocumented required fields are filled in internally – but says nothing about permissions/authentication, whether the created invoice is sent or left as a draft, idempotency, or what happens on validation failure.

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 action front-loaded and no filler. It is appropriately sized, though the second sentence is doing more implicit work than its length suggests.

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?

A mutation tool with no annotations, no output schema, and only 50% parameter description coverage. The description should state at least whether the invoice is created as draft or sent, and what is returned (id, invoice_number), but it leaves these to inference.

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 50%, so the description should compensate for the undocumented half of the parameters (items.name/quantity/description, notes, reference_number) and add meaning beyond the schema. It adds none; the schema already documents the tricky parts (price units, date format, template_name default, invoice_number auto-generation).

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 new invoice") that is unambiguous within the invoice/estimate/customer tool family. It does not explicitly contrast itself with siblings like create_estimate or convert_estimate_to_invoice, but the create semantics are clear enough for selection.

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?

No when-to-use guidance, no prerequisites, and no mention of alternatives (e.g. create_estimate vs convert_estimate_to_invoice). The only weak signal is that undocumented required fields are handled internally, which implies the caller needn't supply extra data, but this is not framed as usage guidance.

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