# Agent Café — Test & Certify Your Paying Agent (x402)

> Agent Café — Test & Certify Your Paying Agent (x402) is a paid API for AI agents from api.402.coffee, paid per call via x402, $0.5/call, status unknown (last checked 2026-09-15).

Accepts a real USDC payment over x402 on Base and returns a signed certificate proving the agent can pay correctly and reject scams

## Facts

- Endpoint: POST https://api.402.coffee/test/recipient/start
- Price: $0.5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-caf-test-certify-your-paying-agent-x402-2c1d8e74
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_K2w5FgwvHfpIREXaIDBIw

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 agent-caf-test-certify-your-paying-agent-x402-2c1d8e74 -d '<json body>'
```

Example prompt: Run the Agent Café payment certification test for my agent — pay the 0.10 USDC order on Base and bring back the certificate and receipt number proving it paid correctly and refused a scam.

## When to prefer this

Use this endpoint when you need to verify or demonstrate that an AI agent correctly implements the x402 payment protocol on Base — specifically when you want a publicly verifiable certificate or receipt as proof. Prefer this over generic payment endpoints when the goal is certification and testing rather than purchasing a real service.

## Known failure modes

- Insufficient USDC balance — payment fails and no certificate is issued
- Agent wallet not configured for Base mainnet — transaction cannot be submitted
- x402 handshake failure — agent does not implement the protocol correctly
- Scam detection triggered — endpoint intentionally rejects malformed or unauthorized payment attempts
- Network congestion on Base — transaction confirmation delayed or dropped

## How this service works

x402 client conformance — recipient-awareness (entry). Opens a two-challenge test: pay the real recipient again, refuse an identically-priced swapped-recipient quote. Total $0.60.

## Output

Returns a JSON object containing the transaction hash, paid status (true/false), order name (e.g. 'espresso'), amount paid, network (Base), currency (USDC), a unique receipt number (AC-XXXXXX format), and a guestbook URL where the certificate is publicly displayed.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {},
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tx": "0x…",
  "paid": true,
  "order": "espresso",
  "amount": "0.10",
  "network": "base",
  "currency": "USDC",
  "receipt_no": "AC-XXXXXX",
  "guestbook_url": "https://402.coffee/wall"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-caf-test-certify-your-paying-agent-x402-2c1d8e74/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.402.coffee](https://www.zero.xyz/host/api.402.coffee/llms.txt)