# Maxwell x402 Doctor — Test Purchase Proxy

> Maxwell x402 Doctor — Test Purchase Proxy is a paid API for AI agents from api.maxwellinternational.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).

Acts as a proxy purchaser that attempts to buy from an x402-gated endpoint on your behalf and returns both receipts (yours and the seller's) along with a clear success/failure verdict.

## Facts

- Endpoint: GET https://api.maxwellinternational.ai/v1/doctor/buy?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/maxwell-x402-doctor-test-purchase-proxy-455ecc22
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9sEnNK2ciywegv4yu-ic3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability maxwell-x402-doctor-test-purchase-proxy-455ecc22
```

Example prompt: Run a test purchase on this x402 endpoint for me — use a GET request to that seller URL and tell me the verdict, both receipts, and exactly what came back or how it failed.

## When to prefer this

Use this endpoint when you need to test or debug an x402-gated paid API endpoint end-to-end without building your own buyer client. It is specifically designed for developers and agents who want to verify that a micropayment seller endpoint is properly configured, live, and returning its promised content — and who want explicit receipts and failure diagnostics rather than just a ping or HTTP status check.

## Known failure modes

- Seller endpoint is unreachable or returns an error — verdict will indicate failure with details
- Seller price exceeds $1 USDC cap — request rejected before attempting
- Daily rate limit exceeded (one test per wallet per endpoint per day) — returns limit error
- Insufficient funds to cover seller price + 1 cent + 10% fee — payment not attempted
- Invalid HTTP method provided (only GET, HEAD, DELETE allowed) — schema validation error
- Target URL is not a valid x402 endpoint — returns failure verdict with diagnosis

## How this service works

Test-buy any x402 endpoint (USDC on Base, seller price up to $1). Pass url and the seller price: you pay price + $0.01 + 10% (e.g. $0.05 costs $0.065), charged per attempt, delivered or not. Seller asks less: we buy at its price and keep the rest. Asks more: nothing bought, payment kept. No price: $0.01 lookup returns the exact price. Returns the seller answer, both receipts, a verdict and a report id.

## Output

Returns a JSON object with a 'verdict' field (e.g. 'delivered' or a failure state), a disclosure string, and both the buyer's and seller's payment receipts. On failure, the response explains exactly how and where the transaction broke down.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "verdict": "delivered",
  "disclosure": "You pay for the attempt."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/maxwell-x402-doctor-test-purchase-proxy-455ecc22/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.maxwellinternational.ai](https://www.zero.xyz/host/api.maxwellinternational.ai/llms.txt)