# FarOut Pay-Per-Call LLM Inference via x402 (GPT-5.6-Luna)

> FarOut Pay-Per-Call LLM Inference via x402 (GPT-5.6-Luna) is a paid API for AI agents from farouter.tech, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Runs a single OpenAI-compatible chat completion request against GPT-5.6-Luna, billed per call in USDC via the x402 payment protocol — no API key or account required.

## Facts

- Endpoint: POST https://farouter.tech/v1/metered/models/gpt-5.6-luna/chat/completions
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/farout-pay-per-call-llm-inference-via-x402-gpt-5-6-luna-c0170cb2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_L0mA0kIkpbnNpargvmSIB

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 farout-pay-per-call-llm-inference-via-x402-gpt-5-6-luna-c0170cb2 -d '<json body>'
```

Example prompt: Ask GPT-5.6-Luna via FarOut to explain the difference between proof-of-work and proof-of-stake in simple terms — keep the response under 200 tokens and pay per call in USDC on Base.

## When to prefer this

Choose this endpoint when your agent holds a crypto wallet (Base or Solana) and needs on-demand LLM inference without a pre-existing API key or subscription. Ideal for autonomous agents, hackathon prototypes, or multi-tenant systems where per-call cost accountability in USDC is required. Prefer it over traditional OpenAI or Anthropic APIs when you want zero account setup, transparent per-request pricing, and failed calls to carry no charge.

## Known failure modes

- 402 Payment Required — wallet has insufficient USDC balance for the quoted amount
- 400 Bad Request — missing or malformed messages array or invalid model ID
- 503 / upstream error — underlying model provider unavailable
- Streaming interruption — SSE stream drops mid-response if connection is lost
- Quote mismatch — actual token count exceeds max_tokens budget causing truncation

## How this service works

Pay-per-call LLM inference over x402. Frontier models (GLM, GPT, Gemini, Kimi, DeepSeek, MiniMax) billed per request in USDC on Base or Solana mainnet. No API key, no account. The 402 quotes your exact request; failed calls are never charged.

## Output

Returns an OpenAI-compatible JSON object containing the assistant's reply message, finish reason (e.g. 'stop'), and token usage counts (prompt_tokens, completion_tokens). Failed or rejected calls are not charged.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "type": "string",
   "description": "Model id from GET /v1/metered/models, e.g. glm-5.3. No provider prefix."
  },
  "stream": {
   "type": "boolean",
   "description": "SSE streaming."
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "enum": [
       "system",
       "user",
       "assistant",
       "tool"
      ],
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    }
   },
   "description": "Chat messages, [OI]-compatible {role, content}."
  },
  "max_tokens": {
   "type": "integer",
   "description": "Output token budget. Drives the quote directly."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "usage": {
   "prompt_tokens": 6,
   "completion_tokens": 8
  },
  "choices": [
   {
    "message": {
     "role": "assistant",
     "content": "Hello! How can I help?"
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/farout-pay-per-call-llm-inference-via-x402-gpt-5-6-luna-c0170cb2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from farouter.tech](https://www.zero.xyz/host/farouter.tech/llms.txt)