OpenAI GPT-5.6 Luna Chat Completions (x402, USDC)

x402

OpenAI GPT-5.6 Luna Chat Completions (x402, USDC) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-03).

Runs chat completions against the GPT-5.6-Luna model (up to 272K input tokens) with pay-per-call billing in USDC via the x402 protocol.

Price / call$0.001

Seller volume →—

Success—

StatusUnknown

How this service works

gpt-5.6-luna: OpenAI GPT 5.6 Luna (<=272K input tokens) chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 0.1/0.6, Standard 0.2/1.2, Fast 0.4/2.4; pick with service_tier. Plus $0.0005 (Base) or $0.0005 (Solana) per call; the quote charges input plus 10% of max_tokens. Levels: none, low, medium, high, xhigh (model gpt-5.6-luna:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

Output

Returns a standard OpenAI chat.completion JSON object containing the assistant's message content, finish_reason (stop/tool_calls/length), prompt and completion token counts, the service_tier used, and a unique completion ID. Empty responses (when the model produces no content) are billed at $0.

Example use cases

Agentic reasoning with adjustable depth

“Use GPT-5.6 Luna at the 'high' reasoning level to analyze this legal contract snippet and tell me what liability clauses are present — keep max_tokens to 512 and use flex tier to save cost.”

Structured JSON output from chat

“Call GPT-5.6 Luna with a response_format set to JSON and ask it to extract the product name, price, and SKU from this raw product description: 'Blue Widget XL — SKU 99321, now only $14.99!' — use standard tier for reliability.”

Tool-calling agent loop

“Send a message to GPT-5.6 Luna with my tools list attached, asking it to look up the current weather in Tokyo and return a structured tool call — use fast tier so it responds quickly.”

Technical details

Endpoint

POSThttps://openai.mm.family/x402/v1/models/gpt-5.6-luna/chat/completions?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need GPT-5.6 Luna specifically, want pay-per-call USDC billing without an OpenAI subscription, need to tune reasoning depth via model suffix levels (none through xhigh), or are building agents on the x402 payment protocol. Prefer over o3 or o4-mini when you want a balance of reasoning quality and cost (Flex at $0.10/$0.60 per 1M tokens). Use gpt-5.5-long or gpt-6-sol-long siblings for inputs exceeding 272K tokens.

Side effects

402 Payment Required — insufficient USDC balance or x402 payment header missing/invalid
400 Bad Request — invalid model name, unsupported service_tier, or malformed messages array
context length exceeded — input tokens surpass the 272K limit for this model variant
rate limiting — too many concurrent requests at the chosen service tier
empty completion returned — model produced no output (billed $0 but no useful result)
timeout — fast/flex tier may deprioritize requests under load causing delayed or dropped responses

Input

Schema · Request body

Field	Type	Description
model	string
tools	array
stream	boolean
messages	array
max_tokens	integer
service_tier	string
response_format	object
reasoning_effort	string

Output

Schema · Response

{
  "type": "json",
  "example": {
    "id": "chatcmpl-x",
    "model": "gpt-5.6-luna",
    "usage": {
      "total_tokens": 9,
      "prompt_tokens": 8,
      "completion_tokens": 1
    },
    "object": "chat.completion",
    "choices": [
      {
        "index": 0,
        "message": {
          "role": "assistant",
          "content": "Hello",
          "refusal": null
        },
        "finish_reason": "stop"
      }
    ],
    "service_tier": "flex"
  }
}

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