Get PayPay Payment Details

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description doesn't need to repeat safety. It adds value by disclosing the return statuses and the polling-vs-one-off distinction, which is useful behavioral context. It doesn't contradict annotations and provides extra detail beyond them.

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 compact paragraphs (English and Japanese) that front-load the purpose and statuses, then give usage guidance. No redundant sentences; every line 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?

With only one parameter, no output schema, and read-only annotations, the description covers the essential: what it does, the parameter source, and when to use it. It could mention the response structure beyond statuses, but for a simple status check it is sufficient.

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 schema description for merchant_payment_id is already present (100% coverage), and the description adds context by noting it's 'the merchantPaymentId used when creating the QR code', helping the agent locate the correct identifier. This goes beyond the schema's basic type definition.

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 action (fetch status and details) and the resource (payment by merchantPaymentId). It lists the exact possible statuses, distinguishing it from sibling tools like wait_for_payment. The purpose is unambiguous and specific.

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?

Explicitly states when to use it: 'Use this for one-off status checks. For active polling, prefer wait_for_payment.' This gives clear context and directs to an alternative, leaving no ambiguity about when to select this tool.

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