# Model Access Gateway – Gemini 4 Argon

> Model Access Gateway – Gemini 4 Argon is a paid API for AI agents from agent402-arb.rosariovitale0096.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-18).

Provides OpenAI-compatible chat completions via the Gemini 4 Argon model, billed per request in USDC on Base using the x402 payment protocol — no API key required.

## Facts

- Endpoint: POST https://agent402-arb.rosariovitale0096.workers.dev/llm/gemini-4-argon?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/model-access-gateway-gemini-4-argon-af8bf21e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EgdMYw8OKL-c1m-ogQ1H5

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 model-access-gateway-gemini-4-argon-af8bf21e -d '<json body>'
```

Example prompt: Send this conversation to Gemini 4 Argon and get a response: system prompt is 'You are a helpful assistant', user message is 'Explain quantum entanglement in two sentences' — pay the per-request fee in USDC automatically.

## When to prefer this

Choose this endpoint when you need Gemini 4 Argon chat completions with zero signup friction, pay-per-call USDC billing via x402, and OpenAI API compatibility — ideal for agents that manage their own crypto wallets and want to avoid monthly subscriptions or API key management.

## Known failure modes

- Payment failure if USDC balance is insufficient or x402 handshake fails
- 402 Payment Required if the payment header is missing or malformed
- Invalid request body if required fields (messages, model) are absent
- Model unavailability if Gemini 4 Argon is temporarily offline upstream
- Rate limiting or worker timeout on the Cloudflare edge if the request is too large
- Malformed JSON body resulting in a 400 error

## How this service works

LLM inference API: OpenAI-compatible chat completions for 136 AI models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen, Kimi, GLM), paid per call in USDC on Base with x402. No account, no API key, automatic refund if the model fails.

## Output

Returns an OpenAI-compatible chat.completion JSON object containing the assistant's reply message, finish reason (e.g. 'stop'), token usage breakdown (prompt, completion, total tokens), a completion ID, creation timestamp, and the model name used.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Optional: fixed by the route (google/gemini-4-argon)"
  },
  "tools": {
   "type": "array"
  },
  "stream": {
   "type": "boolean",
   "description": "true: server-sent events after payment"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool",
       "developer"
      ],
      "type": "string"
     },
     "content": {
      "type": [
       "string",
       "array",
       "null"
      ]
     }
    }
   },
   "minItems": 1
  },
  "max_tokens": {
   "type": "integer",
   "maximum": 16384,
   "minimum": 1,
   "description": "Optional, default 4096"
  },
  "temperature": {
   "type": "number",
   "maximum": 2,
   "minimum": 0
  },
  "response_format": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-7f3c2a91",
  "model": "google/gemini-4-argon",
  "usage": {
   "total_tokens": 10,
   "prompt_tokens": 9,
   "completion_tokens": 1
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "OK"
    },
    "finish_reason": "stop"
   }
  ],
  "created": 1791979200
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/model-access-gateway-gemini-4-argon-af8bf21e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402-arb.rosariovitale0096.workers.dev](https://www.zero.xyz/host/agent402-arb.rosariovitale0096.workers.dev/llms.txt)