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

Goes well beyond the annotations: discloses the four data sources, the GO/HOLD/STOP output contract with supporting signals, the fraud pattern it targets (real-looking name on a weeks-old domain), and the full auth/pricing model ($0.12 per call via x402 on Base, prepaid x-credit-token header for unlimited, 1 free call/day, no API key required). Annotations only cover safety and read-only nature; the description carries the rest.

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?

Front-loaded with the decision question and the four sources, then the output shape, then the use case, then pricing. Every sentence carries information, though the pricing/auth clause is dense enough to slightly dilute the core message.

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?

An output schema exists, so return-value explanation is not required, and the description still states the output form (single GO/HOLD/STOP plus signals). With sourcing, cost, auth, and trigger context all present, an agent has everything needed to call it 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 100%, so the parameters (name/email/domain) are already fully documented in the schema, including the fallback rule that email's domain is used when 'domain' is omitted. The description adds no syntax or format detail beyond that, so the high-coverage baseline of 3 applies.

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?

Names a precise verb+resource ('Should you pay this supplier?') and enumerates the four concrete checks it performs (RDAP domain age, DNS mail deliverability, OFAC, LEI registry). An agent can distinguish it from domain_check, sanctions_name, company_lei, and address_check, which each do only one of these signals.

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?

'Built for the moment an agent has to trust an invoice, a new vendor or a payment-detail change' gives a clear triggering context. It stops short of naming the narrower sibling tools it replaces, so there is no explicit when-not guidance, but the use case is unambiguous.

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