Who it is for

Critical agents where every error costs money.

• Payments, bookings or sensitive data
• Before launching an agent to many users

How an agent buys it

POST https://a-upgradenet.com/x402/tool-call-audit-max
Content-Type: application/json

{
  "input": {
    "system_prompt": "You are the support agent of an online store.",
    "tools": [
      {
        "name": "lookup_order",
        "description": "Find an order",
        "parameters": {
          "type": "object",
          "properties": {
            "order_id": {
              "type": "string"
            }
          },
          "required": [
            "order_id"
          ]
        }
      }
    ]
  }
}

1) Answers 402 with the price (PAYMENT-REQUIRED)
2) The agent signs the payment (EIP-3009, USDC on Base) and repeats with PAYMENT-SIGNATURE
3) Receives the result + PAYMENT-RESPONSE

Example response

{
  "status": "completed",
  "tier": "basic",
  "report": {
    "baseline": {
      "held_out": {
        "passed": 6,
        "total": 11,
        "rate": 0.55
      }
    },
    "improved": {
      "held_out": {
        "passed": 10,
        "total": 11,
        "rate": 0.91
      }
    },
    "delta_points": 36.4,
    "verdict": "improved",
    "recommended": {
      "system_prompt": "...",
      "tools": [
        "..."
      ]
    },
    "remaining_failures": []
  }
}