# GPT-5.4-mini Standard Chat Completions (GET, x402)

> GPT-5.4-mini Standard Chat Completions (GET, x402) is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.00293/call, status unknown (last checked 2026-09-15).

Generates standard GPT-5.4-mini chat completions via a GET query-parameter interface, paid per-call with USDC on Base via x402

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/chat/completions/standard
- Price: $0.00293/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gpt-5-4-mini-standard-chat-completions-get-x402-15cd4648
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QUtZs3ALzgl-cKWC7yhj2

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 gpt-5-4-mini-standard-chat-completions-get-x402-15cd4648
```

Example prompt: Ask GPT-5.4-mini to summarize this in one sentence: 'The quarterly revenue grew 23% year-over-year, driven primarily by enterprise subscriptions and international expansion into Southeast Asia.' Keep it under 50 words.

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call GPT-5.4-mini chat completion without an OpenAI subscription, especially for routing decisions, short extractions, quick Q&A, or buyer trials. Prefer it over heavier tiers when output is under 256 tokens and cost-sensitivity matters. Use the GET variant when you cannot send a request body.

## Known failure modes

- Payment not provided or insufficient — x402 payment required error returned
- Input exceeds 24000 character limit — request rejected
- max_tokens exceeds 256 — validation error
- Invalid model enum value — rejected with schema error
- Upstream model unavailable — 502 or 503 error
- Malformed query parameters — 400 bad request

## How this service works

GPT-5.6 Luna chat for mainstream short answers, routing decisions, extraction helpers, and buyer trials. The legacy mini path remains available as a compatibility alias. Model tier: GPT-5.6 Luna Standard; upstream model: gpt-5.6-luna. Pay up to $0.00293 per request with x402 USDC on Base or choose the fixed-price Solana USDC option when advertised. Exact fixed-price payment and Base upto token-metered payment are both accepted when clients support them; upto settlements use actual response...

## Output

Returns an OpenAI-compatible chat completion object containing an id, object type, model name, choices array with the generated message text, and usage statistics (token counts). The response mirrors the standard OpenAI chat completions response format.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "additionalProperties": true
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string"
      },
      "input": {
       "type": "string"
      },
      "model": {
       "enum": [
        "gpt-5.6-sol",
        "gpt-5.6",
        "gpt-5.6-luna",
        "gpt-5.6-terra",
        "gpt-5.5",
        "gpt-5.3-codex",
        "gpt-5.4"
       ],
       "type": "string"
      },
      "prompt": {
       "type": "string"
      },
      "system": {
       "type": "string"
      },
      "message": {
       "type": "string"
      },
      "max_tokens": {
       "type": "integer",
       "maximum": 128000,
       "minimum": 1
      },
      "system_prompt": {
       "type": "string"
      },
      "max_output_tokens": {
       "type": "integer",
       "maximum": 128000,
       "minimum": 1
      }
     },
     "additionalProperties": true
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "id",
      "object",
      "model",
      "choices"
     ],
     "properties": {
      "id": {
       "type": "string"
      },
      "model": {
       "type": "string"
      },
      "usage": {
       "type": "object"
      },
      "object": {
       "type": "string"
      },
      "choices": {
       "type": "array"
      }
     },
     "additionalProperties": true
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "chatcmpl_example",
  "model": "gpt-5.6-luna",
  "usage": {
   "total_tokens": 44,
   "prompt_tokens": 32,
   "completion_tokens": 12
  },
  "object": "chat.completion",
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "A concise answer from GPT-5.5."
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gpt-5-4-mini-standard-chat-completions-get-x402-15cd4648/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gpt55.558686.xyz](https://www.zero.xyz/host/gpt55.558686.xyz/llms.txt)