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

The description discloses the key behavior: registering a payment as a transaction entry linked to an invoice, supporting only manual cards, and accepting bulk invoice_date_or_ids. It adds value beyond the annotations by explaining the manual/automatic distinction and the lookup requirement. It does not detail side effects like whether the payment is also marked as paid, but the provided context is solid.

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 compact and well-structured: it leads with the core purpose, then adds the alternative tool, then provides lookup guidance, and finally notes bulk support. Every sentence carries information with no redundancy.

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 the tool has no output schema and 7 parameters, the description offers enough context to invoke it correctly: required fields are identifiable, the linking parameter format is specified, and bulk support is mentioned. It does not describe the return value or error cases, but the essential invocation guidance is present.

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 0%, so the description carries the burden. It explains invoice_date_or_id format (id or YYYY-MM), mentions bulk invoice_date_or_ids, and advises using names for card/account fields. The obvious parameters (amount, date, observation) are self-explanatory, and the key linking parameter is well documented, though source_account and observation get only indirect coverage.

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 states a specific action ('Registra o pagamento de uma fatura de cartão MANUAL como lançamento') and clearly identifies the resource. It also distinguishes itself from the sibling tool inform_invoice_payment, which handles automatic cards, so an agent can immediately tell which tool to use.

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?

Usage context is explicit: manual card invoices should use this tool, automatic cards should use inform_invoice_payment. It also tells the agent to prefer card/account names, list invoices with get_credit_card_invoices, pass invoice_date_or_id (id or YYYY-MM), and never invent values. This is strong, actionable guidance.

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