Get sales invoice

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

Annotations already cover readOnly, idempotent, and non-destructive behavior. The description adds useful context beyond that: the response will include lines, payments, and notes, which helps set expectations for what is returned. It does not contradict the annotations.

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?

A single, front-loaded sentence that delivers the action, the identifier type, and the expected payload without wasted words. Every phrase 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?

For a simple read tool backed by strong annotations and only two parameters, the description is nearly complete. It gives the lookup key, the selected scope, and important return content. A brief sibling-routing note would round it out, but nothing essential for a correct call 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 only 50% because sales_invoice_id has no schema description. The description fills this gap by clarifying that the id is a Moneybird id, which is essential for selecting this tool over the invoice-id/reference lookup siblings. The optional administration_id is already described in the schema.

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 clearly states a specific verb and resource: 'Retrieve one sales invoice by its Moneybird id.' It also distinguishes itself from list/find/download siblings by making the id namespace explicit and by specifying the returned content (lines, payments, notes).

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 description implies the correct use case—you have a Moneybird sales_invoice_id and want the full invoice—but it never explicitly names alternatives like find_sales_invoice_by_invoice_id or find_sales_invoice_by_reference, nor gives conditions for when to choose them instead.

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