Kirim SATU permintaan TANPA membayar ke endpoint x402 publik dan periksa bentuk 402-nya.
Diperiksa: status 402, ada tantangan pembayaran, x402Version, accepts[], jaringan,
aset, format payTo, dan konsistensi harga. Tidak mengirim kredensial apa pun.
url: hanya https pada port 443, host publik. Redirect tidak diikuti.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes |
Changes observed during successful MCP inspections.
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 well: it discloses that exactly one request is sent, that no credentials are transmitted, that redirects are not followed, and that only https/443 public hosts are permitted. What it omits is rate-limit or repeat-call behavior and whether failures are reported as errors versus a validation verdict.
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 short lines, front-loaded with the action and the no-payment constraint, followed by the concrete checks and then the url constraints. Every clause adds information; nothing is redundant.
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, no-output-schema diagnostic tool this is nearly complete: the enumerated checks (status 402, payment challenge, x402Version, accepts[], network, asset, payTo format, price consistency) effectively describe what the caller learns back. Only the shape of the result (pass/fail vs structured report) is left implicit.
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 0% and the single 'url' parameter is entirely undocumented in the schema, so the description must compensate — and it does, constraining it to https on port 443 with a public host and no redirect following. That is meaningful semantics beyond the bare 'string' type, though it doesn't explain how a rejected host is reported.
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 verb and resource: send one unpaid request to a public x402 endpoint and inspect the shape of its 402 response. The scope (single request, no payment) is unambiguous. However, it never names or distinguishes itself from the sibling verifikasi_pembayaran or info_pembayaran, so the agent must infer that this validates the *challenge response* rather than a payment.
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?
Usage is implied rather than stated: this is clearly a pre-payment diagnostic, and the constraints ('TANPA membayar', 'Tidak mengirim kredensial') signal when it is safe to call. But there is no explicit when-to-use/when-not or routing to alternatives such as verifikasi_pembayaran for actual payment checks.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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