cancel_payment

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

With no annotations, the description carries the full burden of behavioral disclosure. It explains the purpose but not side effects, idempotency, what happens if the payment already completed, or error conditions. This is a significant gap for a cancellation tool.

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 concise with two sentences: one for purpose and one for the parameter. No fluff or repetition, and the key information is front-loaded.

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?

The tool is simple (one parameter, output schema exists), and the purpose is clear. However, it lacks behavioral details like idempotency, reversibility, or error handling, which is expected for a cancellation action. It is adequate but not fully complete.

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 input schema has zero description coverage, so the description compensates fully by explaining that `payment_request_id` is assigned by the ACQP, identifies the original payment order, and has a maximum length of 64 characters. This adds meaningful context beyond the bare 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 the tool cancels a payment, and specifies the exact conditions (no payment result received after expiry, or ACQP closes before result). This distinguishes it from sibling tools like create_payment, query_payment, and create_refund.

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 provides clear context for when to use the tool (proactive cancellation after expiry or early closure) but does not explicitly mention when not to use it or alternatives. It implies usage but lacks direct exclusions.

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