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

With no annotations, the description carries the full burden. It transparently explains the on-chain enforcement, the required follow-up call, and the need to wait for payment_incoming. But it does not mention permissions, side effects, or what happens if the payment session expires. This is a meaningful gap for a tool that creates a financial request.

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 three sentences, front-loaded with the core purpose, then return values, then the required workflow. Every sentence adds essential information and there is no filler or 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?

For a tool with no output schema and no annotations, the description covers the key elements: what it creates, what it returns, the on-chain call the payer must make, and when to deliver the resource. It could mention expiry or failure modes, but the existing content is sufficient for an agent to invoke the tool correctly.

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 100%, so the baseline is 3. The description adds no extra detail about the parameters themselves; it only reuses destination and amount in the context of return values. The schema already explains all parameters, so the description provides marginal benefit here.

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 the exact purpose: 'Create a x402 payment request (HTTP 402) for a resource you sell to another agent.' It uses a specific verb and resource, and the mention of returning payment details and the follow-up contract call clearly distinguishes it from sibling tools like payment_incoming and payment_status.

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 gives clear context: use it when selling a resource to another agent. It also provides a workflow instruction ('Deliver the resource only after payment_incoming confirms fulfilment') that implies when to wait for payment. However, it does not explicitly name alternatives or state when not to use this tool, so it lacks explicit exclusions.

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