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

Annotations only declare readOnly/mutation flags, so the description must carry the money semantics — and it does: exact prices, settlement only on delivery, idempotent retry with no double charge, and the payment-cap caveat. This is precisely the context an agent needs before triggering an irreversible spend.

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?

Price and payment model are front-loaded, then the call sequence, then edge cases — a sensible ordering. It is dense but nearly every sentence carries operational instructions; the website-comparison sentence is the one low-value line.

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, open-world tool with no output schema, the description covers price, tier selection, the handshake, return shape (JSON report plus private link), retry safety, and client configuration. Nothing needed to invoke it correctly is missing.

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 86%, so the baseline is 3; the description still adds real value by explaining that `payment` is the base64 PAYMENT-SIGNATURE obtained from the first, payment-free call, and that `prompts` are answered before generated questions fill to 25. Only `category` remains undocumented in either place.

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?

States a specific resource (the paid AI visibility report) with concrete tiers and prices, and identifies it as the paid counterpart to the website reports. An agent can tell immediately this is the x402-gated purchase path, distinct from scan_site and get_scan_details.

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?

Gives an explicit two-step invocation protocol: call once without `payment` to obtain x402 requirements, then call again with identical arguments plus the base64 signature. It also prescribes behavior for the failure case (retry with the same payment) and for a client payment cap (raise to 49 USDC for Full).

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