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

With no annotations, the description carries the full burden. It usefully discloses that it probes a remote URL and performs an external facilitator cross-check, and that findings are 'advisory' (non-blocking), but it does not say whether the probe can trigger real payment settlement, whether it is strictly read-only, what timeouts or rate limits apply, or what auth is needed. These are material gaps for a tool that reaches out to third-party infrastructure.

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?

A single front-loaded sentence with the resource and check set stated before the output promise; the parenthetical enumeration earns its space. Mildly dense jargon ('scar-tissue findings') costs a little clarity, but there is no 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 two-parameter tool with no output schema, the description does the needed work: it names the checks and describes the return value as a graded 0-100 report with per-failure remedies. What remains missing is failure/error behavior and the conditions under which the optional payment_signature must be present.

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 both parameters are already documented, and the description adds no further meaning. In particular it does not clarify the conditional role of payment_signature (when a settled signature must be supplied versus when the URL alone suffices), which is the one genuinely ambiguous parameter.

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 (a deployed x402 resource URL) and a specific operation (seller-side conformance pre-flight check), then enumerates the checks performed (schema validation, mechanism reachability, facilitator cross-check, advisory findings) and the output form (graded 0-100 report with per-failure remedies). None of the siblings (agent_readiness, btc_regime, echo_probe, resume_eval) overlap with this domain, so an agent can route to it confidently.

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?

'Pre-flight' implies it is run against a deployed endpoint before relying on it, but the description never states when to use it versus the siblings, nor any prerequisites (must the URL be an x402-enabled seller endpoint?). Usage is only inferable from the name and phrasing.

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