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AgentPay x402 Facilitator

by x402-agent-pay.com · remote · no sign-in to list tools · v1.0.0 · published by com.x402-agent-pay

Verify signed x402 payments; treasury-scoped settlement is irreversible.

Deletes · 1Changes · 1
CompareRegistry entry

2 tools: 1 can delete or cancel things and 1 change things.

Scanned Oct 21, 2026

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

claude mcp add --transport http facilitator https://x402-agent-pay.com/facilitator/mcp

Findings

Matches of fixed checks, with the text they matched.

6 warn
  • Warnx402_facilitator_verify

    The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

    Matched text

    inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

    What this check looks for
  • Warnx402_facilitator_verify

    The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 44-character base64 string.

    Matched text

    inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...Bf3451a03 (Base) or 6aCEuwH3PYx99cEmRz45otfxk39uF7ewGhqmvxfXisSG (Solana)."

    What this check looks for
  • Warnx402_facilitator_verify

    The input schema at properties.body.properties.payment_requirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

    Matched text

    inputSchema.properties.body.properties.payment_requirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

    What this check looks for
  • Warnx402_facilitator_settle

    The description contains a 42-character base64 string.

    Matched text

    description: "...AgentPay treasury (0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 on Base / 6aCEuwH3P..."

    What this check looks for
  • Warnx402_facilitator_settle

    The description contains a 44-character base64 string.

    Matched text

    description: "...Bf3451a03 on Base / 6aCEuwH3PYx99cEmRz45otfxk39uF7ewGhqmvxfXisSG on Solana), then br..."

    What this check looks for
  • Warnx402_facilitator_settle

    The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

    Matched text

    inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

    What this check looks for

Tools

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

2 tools

Deletes or cancels 1Claude Code: deny
  • x402_facilitator_settleIRREVERSIBLE SIDE EFFECT: forwards the envelope to POST https://x402-agent-pay.com/facilitator/settle.3 findings

    Why it is in this group

    • The description says "IRREVERSIBLE".
    • The server marks it destructive (destructiveHint: true).

    Findings

    • Warn

      The description contains a 42-character base64 string.

      Matched text

      description: "...AgentPay treasury (0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 on Base / 6aCEuwH3P..."

      What this check looks for
    • Warn

      The description contains a 44-character base64 string.

      Matched text

      description: "...Bf3451a03 on Base / 6aCEuwH3PYx99cEmRz45otfxk39uF7ewGhqmvxfXisSG on Solana), then br..."

      What this check looks for
    • Warn

      The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

      Matched text

      inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

      What this check looks for
    Description, as the server wrote it
    IRREVERSIBLE SIDE EFFECT: forwards the envelope to POST https://x402-agent-pay.com/facilitator/settle. The existing facilitator first re-runs verify(), then refuses PAYEE_NOT_SERVED_HERE unless payTo is the AgentPay treasury (0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 on Base / 6aCEuwH3PYx99cEmRz45otfxk39uF7ewGhqmvxfXisSG on Solana), then broadcasts via Coinbase CDP and returns a transaction hash. Malformed, unsigned, out-of-scope, or unverified payloads are rejected before any external transfer. This adapter never signs, never holds keys, and never bypasses those gates. Do not call this as a dry run.

    Annotations the server declares

    • destructiveHint: true
    • idempotentHint: false
    • openWorldHint: true
    • readOnlyHint: false
    • title: Settle x402 payment (irreversible)
Changes things 1Claude Code: ask
  • x402_facilitator_verifyForward an x402 payment envelope to POST https://x402-agent-pay.com/facilitator/verify.3 findings

    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

    • Warn

      The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

      Matched text

      inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

      What this check looks for
    • Warn

      The input schema at properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description contains a 44-character base64 string.

      Matched text

      inputSchema.properties.body.properties.paymentRequirements.anyOf[0].properties.payTo.description: "...Bf3451a03 (Base) or 6aCEuwH3PYx99cEmRz45otfxk39uF7ewGhqmvxfXisSG (Solana)."

      What this check looks for
    • Warn

      The input schema at properties.body.properties.payment_requirements.anyOf[0].properties.payTo.description contains a 42-character base64 string.

      Matched text

      inputSchema.properties.body.properties.payment_requirements.anyOf[0].properties.payTo.description: "...e AgentPay treasury 0x367F1b3D8Ca90D1e087481a9A40d585Bf3451a03 (Base) or 6aCEuwH3P..."

      What this check looks for
    Description, as the server wrote it
    Forward an x402 payment envelope to POST https://x402-agent-pay.com/facilitator/verify. Recovers the EIP-712 signer, checks payee/amount/expiry/nonce/USDC balance and spend authority. Free. No gas. No broadcast. Returns isValid plus invalidReason when the payload cannot clear. Authorization still lives in the existing facilitator implementation; this tool only forwards the JSON body.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • readOnlyHint: true
    • title: Verify x402 payment

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 1.0.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http facilitator https://x402-agent-pay.com/facilitator/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": [],
    "ask": [
      "mcp__facilitator__x402_facilitator_verify"
    ],
    "deny": [
      "mcp__facilitator__x402_facilitator_settle"
    ]
  }
}

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 facilitator. Review it before you use it.