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x402 Preflight

by chico10117 · remote · no sign-in to list tools · v1.0.1 · published by GitHub user chico10117

Inspect and validate an x402 endpoint before an autonomous agent spends USDC.

Changes · 2
CompareRegistry entry

3 tools: 2 change things and 1 only read.

Scanned Oct 21, 2026

3 checks matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http x402-preflight https://x402.chikocorp.com/mcp

Findings

Matches of fixed checks, with the text they matched.

3 info

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

3 tools

Changes things 2Claude Code: ask
  • audit_x402_endpointTechnical audit for API developers launching or debugging x402.1 finding

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Info

      The input schema at properties.resource_url.description mentions "credentials".

      Matched text

      inputSchema.properties.resource_url.description: "...402 resource to inspect without payment credentials."

      What this check looks for
    Description, as the server wrote it
    Technical audit for API developers launching or debugging x402. Returns deeper read-only evidence of payment configuration, schemas, redirects, CORS, cache behavior, OpenAPI, llms.txt, agent metadata, and x402 discovery consistency. Requires an explicitly authorized x402 purchase; does not test settlement, paid delivery, or actual marketplace indexing.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
  • order_x402_remediationDiagnostic report for API developers launching or debugging x402.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    Diagnostic report for API developers launching or debugging x402. An explicitly authorized x402 purchase creates a durable order for asynchronous findings, evidence, and prioritized fix recommendations in JSON/Markdown. The receipt is not the completed report. No implementation, human consultation, target payment, deployment, or guaranteed marketplace indexing.

    Annotations the server declares

    • readOnlyHint: false
    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: true
Only reads 1Claude Code: allow
  • inspect_x402_endpointFree endpoint check for API developers launching or debugging x402.2 findings

    Why it is in this group

    • The name "inspect_x402_endpoint" says "inspect": a word for reading.

    Findings

    • Info

      The description mentions "credentials".

      Matched text

      description: "...mparison policy without sending payment credentials. ALLOW and BLOCK are policy decisions,..."

      What this check looks for
    • Info

      The input schema at properties.resource_url.description mentions "credentials".

      Matched text

      inputSchema.properties.resource_url.description: "...402 resource to inspect without payment credentials."

      What this check looks for
    Description, as the server wrote it
    Free endpoint check for API developers launching or debugging x402. Inspect your live payment challenge and caller-selected comparison policy without sending payment credentials. ALLOW and BLOCK are policy decisions, not launch certification; a price-limit BLOCK does not establish a broken integration. Buyer-side inspection remains available.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 1.0.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http x402-preflight https://x402.chikocorp.com/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__x402-preflight__inspect_x402_endpoint"
    ],
    "ask": [
      "mcp__x402-preflight__audit_x402_endpoint",
      "mcp__x402-preflight__order_x402_remediation"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as x402-preflight. Review it before you use it.