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 partially delivers by stating that completed responses include the delivered payload and receipt, and that the poll ends at terminal states. However, it does not disclose authentication requirements, potential side effects (if any), retry behavior, or what responses look like for non-completed states.

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 a single, tightly worded sentence with no filler. It front-loads the core action (poll) and resource (owned x402 relay payment), then adds the key outcome details. Every word contributes meaning.

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 annotations, no output schema, and two undocumented required parameters, the description is too sparse. It explains the completed response but not the retryable or failed response shapes, and it omits any guidance on how the apiKey or relayPaymentId relate to the ownership claim. An agent would likely need additional context to invoke this 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 0%, and the description provides no explanation of the two required parameters, relayPaymentId and apiKey. It does not state that apiKey is an authentication credential or how relayPaymentId should be formatted or obtained. The phrase 'owned' implies ownership of the relay payment but does not clarify the parameter semantics.

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, 'poll', and a specific resource, 'owned x402 relay payment', with explicit terminal states ('completed, retryable, or failed'). This clearly distinguishes the tool from siblings like create_x402_relay_quote, fund_x402_relay_payment, and retry_x402_relay_payment, which perform different actions.

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 implies when to use the tool — after creating/funding a relay payment, to check its status — but it does not explicitly contrast it with alternatives. For example, it mentions 'retryable' as a state but does not direct the agent to retry_x402_relay_payment for that case, and it does not state when not to use this tool.

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