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

With no annotations, the description carries the full behavioral burden and does so well: deterministic, stateless, never pays anyone, returns verdict/components/reasons/signed receipt, and costs $0.01 USDC on Base paid in-band via x402 MCP. It also notes the day-pass alternative through the schema and the direct POST endpoint.

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 payment mechanics are front-loaded, and nearly every clause carries operational information. It is dense and somewhat run-on, with a redundant bracketed title prefix, but it avoids filler.

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 tool with no annotations and no output schema, the description is largely complete: it covers inputs, payment, determinism, and return contents. The main gap is that lookbackDays behavior/default is left unexplained, and the structure of the signed receipt is not detailed.

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 75%, and the description adds useful meaning beyond the schema by explaining that the address can be a Base wallet or the payTo from an endpoint's 402 challenge, and that address and/or endpoint are accepted. The lookbackDays parameter is not explained in either the description or schema, which keeps this from a 5.

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 states a specific verb and resource: score an x402 seller's Base wallet 0-100 from public USDC transfer history. It clearly distinguishes this reputation check from generic payment tools by naming the seller-risk verdict and the exact signals used.

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 clear usage context: 'Before an agent pays an x402 seller' and says to provide an address and/or endpoint. It does not explicitly compare against sibling tools such as should_i_pay or state when not to use it, but the intended moment of use is unambiguous.

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