# OpenAI GPT-5.5 Long Context Chat Completions (via mm.family x402)

> OpenAI GPT-5.5 Long Context Chat Completions (via mm.family x402) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001682/call, status unknown (last checked 2026-10-02).

Provides OpenAI GPT-5.5 chat completions for prompts exceeding 272K input tokens, billed per call in USDC via the x402 payment protocol with configurable quality tiers.

## Facts

- Endpoint: POST https://openai.mm.family/x402/v1/models/gpt-5.5-long/chat/completions?utm_source=zero.xyz
- Price: $0.001682/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-5-5-long-context-chat-completions-via-mm-family-x402-c3626d07
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qjYiH-PQspqMrOuDynOtm

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-5-5-long-context-chat-completions-via-mm-family-x402-c3626d07 -d '<json body>'
```

Example prompt: Send this entire 400-page legal contract text to GPT-5.5 and ask it to identify all indemnification clauses — use the flex service tier and cap output at 2000 tokens.

## When to prefer this

Choose this endpoint when you need GPT-5.5 specifically for prompts exceeding 272K input tokens (book-length documents, large codebases, lengthy transcripts) and want to pay per call in USDC without a direct OpenAI subscription. Prefer it over the standard gpt-5.5 endpoint when your input context is very large, and use the flex tier for cost savings or standard tier for priority throughput. The x402 crypto-native payment model makes it ideal for autonomous agents that manage their own wallets.

## Known failure modes

- Insufficient USDC balance or x402 payment failure results in 402 Payment Required
- Prompt exceeds model context window limits even for long variant
- max_tokens set too low causes truncated or empty responses
- Invalid service_tier enum value causes request rejection
- Streaming errors if network connection drops mid-response
- Rate limiting if too many concurrent calls are made

## How this service works

gpt-5.5-long: OpenAI GPT 5.5 (>272K input tokens) chat completions, paid per call in USDC. Per 1M tokens in/out: Flex (default) 5.0/22.5, Standard 10.0/45.0; 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-5.5-long:<level>). Empty answers are free. Rates: https://openai.mm.family/x402/pricing

## Output

Returns a JSON chat completion object matching the OpenAI API format, including the assistant's message content, role, finish reason, token usage breakdown (prompt, completion, total), model name, and service tier used. Empty responses when the model produces no output are free of charge.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "model": {
   "enum": [
    "gpt-5.5-long",
    "gpt-5.5-long:none",
    "gpt-5.5-long:low",
    "gpt-5.5-long:medium",
    "gpt-5.5-long:high",
    "gpt-5.5-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-5.5-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-5-5-long-context-chat-completions-via-mm-family-x402-c3626d07/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)