List the account's billing documents: paid invoices (one per completed balance top-up, numbers RX-…) and proforma invoices for upcoming top-ups (PF-…), each with amount, status and a PDF link. Company name, address, VAT and the invoice email are edited at rixot.com/billing.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the behavioral burden. It conveys that the operation is a read-only listing through the verb 'List,' and it discloses what each entry contains (amount, status, PDF link). It also usefully points to where billing settings are edited, adding practical context beyond a bare list command.
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?
The description is two focused sentences with no fluff. The primary purpose and output details are front-loaded in the first sentence, and the second sentence adds a relevant operational note about billing settings. Every sentence 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?
Given no output schema, the description adequately explains what the agent will receive: invoice type, amount, status, and PDF link. It also covers the distinction between paid and proforma invoices, which is sufficient for a parameterless list tool.
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?
The tool takes zero parameters stellarly, so there is no parameter semantics burden on the description. The baseline for 0-parameter tools is 4, and the description gives all necessary context without needing to explain input fields.
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 uses a specific verb and resource: 'List the account's billing documents.' It clearly distinguishes between paid invoices (RX-…) and proforma invoices (PF-…), which helps an agent separate this from sibling tools like issue_proforma and send_invoice.
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 establishes clear context: this tool lists existing billing documents and includes both invoice types. It does not explicitly name alternative tools or when-not-to-use cases, but the listing behavior is distinct enough from issuing or sending invoices that an agent can infer appropriate usage.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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