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

With no annotations present, the description carries the full behavioral burden. It discloses the cost, the fact that payment settles before the target is checked, the output form (signed dated receipt with status and detail for all 12 checks), and a caveat about rate limiting. This is strong, though it does not cover failure modes of the payment step itself.

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?

Three dense sentences with no wasted words. The most decision-relevant facts—cost, equivalence to site_audit, and payment method—are front-loaded, followed by the important preflight warning.

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 single-parameter paid tool with no output schema, the description covers what the tool produces, how payment works, how to avoid wasted payment, and how it relates to sibling tools. An agent has enough context to invoke it correctly and interpret the result.

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?

The only parameter, url, is fully described in the schema with a format example at 100% coverage. The description adds little new meaning beyond referring to the target being checked, so the baseline 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?

The description clearly identifies the tool as the paid x402 version of site_audit, performing the same 12-check audit with status and detail in a signed dated receipt. It explicitly differentiates itself from site_audit and site_audit_summary by payment method and preflight usage, so an agent can select it correctly.

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?

The description gives precise routing guidance: use this tool when paying via x402/USDC, use site_audit for card or other MPP methods, and run the free site_audit_summary first to validate the URL and avoid paying for a failed check. This is explicit when-to-use and alternative selection guidance.

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