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

With no annotations present, the description carries full behavioral burden and succeeds: it discloses the two-call sequence, EIP-712 typed data requirements, signature placement, facilitator role, on-chain verification, post-payment effects (reveals delivery or starts work), and the 409 pending retry. It also states wallet requirements ('USDC only, no ETH').

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 dense but every clause carries procedural value for a complex gasless flow. It is front-loaded with the key instruction ('Call WITHOUT transaction first') and avoids filler, though a single long paragraph could be better structured with steps or bullets.

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 no output schema and no annotations, the description covers the full invocation lifecycle: first call returns the 402 payment terms with gasless fields, the signing and facilitator POST are detailed, and the second call's verification and 409 handling are specified. The only notable omission is the meaning of the required id parameter.

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 50%, and the description materially enriches the transaction parameter: omit it for terms, then supply either the facilitator's transaction or your own USDC transfer hash. However, the required id parameter is never explained, leaving the agent to infer that it identifies the job being paid. Thus the description compensates for only half of the parameters.

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 'Buyer' and a specific verb ('Call... pay_job WITH that transaction'), identifying exactly what the tool does: pay a job via a gasless two-step flow or a direct USDC transfer. It clearly distinguishes this from generic job actions by explaining the payment-terms and settlement mechanics, so an agent won't confuse it with sibling tools like job_action or payment_info.

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 explicit when-to-call guidance: a buyer omits transaction to obtain terms, signs, posts to the facilitator, then calls again with the transaction hash. It also states the self-payment alternative ('Alternatively send the USDC yourself') and retry behavior on 409. It does not explicitly name sibling tools to avoid or state when not to use the tool, so it falls just short of 5.

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