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

With no annotations, the description carries the full burden and does so: it discloses the $0.05 per-call cost, the payment network (Base or free Base Sepolia test USDC), the two-step error-then-retry payment handshake, and explicitly that nothing is paid to the inspected resource. Those are exactly the behavioral traits an agent needs before invoking a paid tool.

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?

Information-dense and front-loaded: the core deliverable comes in the first sentence, payment mechanics last. The opening sentence runs long with four chained checks, but every clause earns its place.

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?

No output schema exists, so the description must convey return content — and it enumerates the four findings the report contains, which is enough to set expectations. It doesn't describe the report's structure or error cases (unreachable URL, non-x402 endpoint), a minor remaining gap.

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% and both optional params carry schema descriptions, so baseline is 3. The description adds essentially nothing about the `resource`, `method`, or `network` parameters that the schema does not already state.

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 concrete verb and resource ('one dated report on your own paid resource') and enumerates the checks it performs: 402 validity, Bazaar index membership, router routability, and USDC settlement counts over 24h/7d. The contrast with sellerwatch (a one-shot report vs. presumably ongoing watching) is implied but the sibling is never named, so it falls short of the top band.

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?

Scopes the audience clearly ('For x402 sellers', 'on your own paid resource') and gives a complete payment path: x402-aware MCP clients see a PaymentRequired error first and retry with payment in _meta['x402/payment'], while other callers use `npx -y crosscheckapi`. It never states when to prefer this over sellerwatch or accept/check, so no exclusions are given.

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