# OpenAI gpt-5.6-sol-long Chat Completions (Long Context)

> OpenAI gpt-5.6-sol-long Chat Completions (Long Context) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001291/call, status unknown (last checked 2026-10-02).

Serves GPT-5.6 Sol chat completions for prompts exceeding 272K input tokens, billed per call in USDC via x402

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-5.6-sol-long/chat/completions?utm_source=zero.xyz
- Price: $0.001291/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openai-gpt-5-6-sol-long-chat-completions-long-context-c7c886b1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_uemDDtBtvYFC1gk38vhVN

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 openai-gpt-5-6-sol-long-chat-completions-long-context-c7c886b1 -d '<json body>'
```

Example prompt: I need to process a very long document — probably over 300K tokens — using GPT-5.6 Sol. Please send it through the long-context completions endpoint with the standard service tier and a max of 4096 output tokens, and bill the cost in USDC.

## When to prefer this

Choose this endpoint when your input context exceeds 272K tokens and you need GPT-5.6 Sol capabilities specifically, want pay-per-call USDC billing without an OpenAI subscription, or require x402-compatible micropayment integration. Prefer it over standard GPT-5.6 variants when context length is the primary constraint, and over subscription-based OpenAI access when per-call crypto billing is required.

## Known failure modes

- Insufficient USDC balance causes payment failure before completion
- Prompt exceeds the model's maximum supported context window
- max_tokens set too low causing truncated responses
- Invalid model variant string returns 400 error
- Service tier unavailable at request time returns 503
- Empty or malformed messages array returns validation error
- Rate limiting under high load on selected service tier

## How this service works

gpt-5.6-sol-long: OpenAI GPT 5.6 Sol (>272K input tokens) chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 4.0/15.0, Standard 8.0/30.0, Fast 16.0/60.0; 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-sol-long:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns a JSON chat completion object with an assistant message, finish reason, token usage breakdown (prompt, completion, total), model name, service tier used, and a unique completion ID — identical in structure to the OpenAI Chat Completions API response.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-5.6-sol-long",
    "gpt-5.6-sol-long:none",
    "gpt-5.6-sol-long:low",
    "gpt-5.6-sol-long:medium",
    "gpt-5.6-sol-long:high",
    "gpt-5.6-sol-long:xhigh"
   ],
   "type": "string"
  },
  "tools": {
   "type": "array"
  },
  "stream": {
   "type": "boolean"
  },
  "messages": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "role",
     "content"
    ],
    "properties": {
     "role": {
      "type": "string"
     },
     "content": {
      "type": "string"
     }
    }
   }
  },
  "max_tokens": {
   "type": "integer"
  },
  "service_tier": {
   "enum": [
    "flex",
    "default",
    "standard",
    "auto",
    "fast",
    "priority"
   ],
   "type": "string"
  },
  "response_format": {
   "type": "object"
  },
  "reasoning_effort": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl-x",
  "model": "gpt-5.6-sol-long",
  "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"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openai-gpt-5-6-sol-long-chat-completions-long-context-c7c886b1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from openai.mm.family](https://www.zero.xyz/host/openai.mm.family/llms.txt)