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

Beyond the annotations, the description discloses the paid nature of the call, the challenge-then-signature sequence, and the at-most-once semantic-retry behavior tied to a stable operation id. The 'required ... optional' phrasing for _salt19_operation_id is slightly fuzzy, but it is consistent with the idempotentHint and does not contradict readOnlyHint=false or openWorldHint=true.

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?

Three dense sentences front-load the purpose, then add cost, the retry-preservation workflow, and the idempotency guarantee. There is no filler and every sentence contributes actionable information for an agent.

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 high complexity of 11 parameters, nested objects, and an output schema, the description provides the non-obvious protocol context needed to invoke the payment flow correctly. It does not explain optional correlation parameters such as _salt19_handoff_id or target_salt19_operation_id, but those are optional and the schema already defines their shapes.

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 coverage is 100%, so the baseline is 3. The description adds real meaning for _salt19_operation_id and _x402_payment_signature, but most other parameters such as policy, expected_delivery, target_salt19_operation_id, and _salt19_handoff_id are left to generic 'Input parameter' schema descriptions, and the description does not compensate for their protocol 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 opens with a precise verb and object: 'Verify that an x402 v2 payment payload, settlement evidence, original request, accepted offer, spending policy, and delivered response are mutually bound.' This focuses on a specific verification job and clearly distinguishes commerce-verify from commerce-decision and commerce-receipt siblings, whose purposes are decision and receipt generation rather than cross-artifact binding verification.

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?

It gives actionable workflow guidance: generate one _salt19_operation_id per purchase, preserve it across retries, add _x402_payment_signature after satisfying the challenge, and expect a $0.02 x402 charge. It does not name alternative tools or provide explicit when-not-to-use conditions, so it stops short of a 5.

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