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

Annotations only say it is not read-only, not idempotent, not destructive, and open-world; the description goes well beyond them by disclosing the price (0.05 USDC on Base, chain eip155:8453), the payment protocol details, where the settlement receipt appears (result._meta['x402/payment-response']), and the refund guarantee that failed or refused calls are never charged. Those are exactly the facts an agent needs to avoid unintended spend, and they do not conflict with the annotations.

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 purpose and cost are front-loaded in the first two sentences, and the operational payment instructions follow in a logical order. The HTTP endpoint sentence is useful fallback context, though a few phrases ('One call, one fix') are stylistic rather than informative. Overall it is dense but earns most of its length.

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 paid, non-idempotent, open-world tool with no output schema, the description covers everything an agent needs: input shape, price and chain, the mandatory two-step payment handshake, where the receipt lands, and the no-charge-on-failure guarantee. Nothing material about invoking it correctly is left to inference.

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%, and the schema already documents both fields including the 3-to-600 character bound on 'ask'. The description adds only a light gloss — 'paste the error' for the details parameter and 'what broke' for ask — which maps onto the schema without adding format or example detail beyond it. Baseline 3 is appropriate when the schema carries 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 gives a specific verb and resource — fixes a broken automation — plus a concrete scope list (Zapier, Make, n8n, Power Automate, GitHub Actions or code) and states the deliverable: what the error means plus steps to fix it. It is clear enough to separate from generic siblings like paid_answer, though the inclusion of 'code' leaves some overlap with review_code and paid_review that the description does not resolve.

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 tells the agent exactly how the two-phase x402 flow works: call without payment to receive PaymentRequired terms, then re-call with a signed PaymentPayload. 'One call, one fix' sets the expectation of single-use invocation. It never names an alternative tool or an explicit 'do not use this for X' condition, so it falls 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.