GPT-5.4 pro - Create Chat Completion (AI Model · By )

API Documentation

API Reference

Chat

Create Chat Completion

Supported Model Code

Loading models...

GPT-5.4 pro (gpt-5.4-pro)

gpt-5.4-pro0 models support this endpoint

GPT-5.4 pro is the advanced version of GPT-5.4 from OpenAI, designed to use more compute for deeper reasoning and consistently smarter, more precise responses. It supports text and image inputs with text output, a 1,050,000-token context window, and up to 128,000 output tokens. GPT-5.4 pro supports reasoning effort levels of medium, high, and xhigh, and is best suited for the hardest reasoning tasks, advanced research, complex coding, deep analysis, long-context workflows, and professional applications that require maximum answer quality and reliability.

Create chat completion

https://api.modelstream.ai

POST/v1/chat/completions

Authentication

BearerAuth

AuthenticationBearer <token>

All API requests must be authenticated using a Bearer token in the Authorization header. Please ensure your API key is active.Authorization: Bearer sk-xxxxxx

Parameter Location: Header Param

Request Body

application/json

These parameters come from the selected model form_schema. Switching models updates this list and the request example.

system_prompt?string

Top-level `instructions` for the Responses API; sets global model behavior.

Example Value: You are a helpful and expert assistant.Placeholder: e.g., You are a senior software architect...

prompt*string

RequiredExample Value: Hello! What can you do?Placeholder: Enter your question or instructions...

image_urls?array

Supports multi-image understanding (optional).

Value Range: 0 ≤ value ≤ 10

image_detail?string

Example Value: auto

Enum/Options:

Auto: autoLow: lowHigh: high

reasoning_effort?string

Controls how much reasoning effort the model spends before answering.

Example Value: medium

Enum/Options:

Medium: mediumHigh: highxHigh: xhigh

reasoning_summary?string

Returns a summary of the model reasoning process (Responses-only).

Example Value: auto

Enum/Options:

Auto: autoDetailed: detailed

verbosity?string

Controls how verbose the response is.

Example Value: medium

Enum/Options:

Low: lowMedium: mediumHigh: high

max_output_tokens?number

Example Value: 8192Value Range: 1 ≤ value ≤ 128000

response_format?string

Example Value: text

Enum/Options:

Text: textJSON Object: json_object

store?boolean

Whether to store this response for later retrieval (defaults on for Responses).

Example Value: true

topic?string

Written to metadata.topic for dashboard filtering (Responses-only).

Example Value: general

background?boolean

Run the response asynchronously in the background (for Pro models).

Example Value: false

stream?boolean

Example Value: true

Response Parameters

application/json

200apiDocs.responses.successCreateResponse

id?string

Parameter description for Id

object?string

Parameter description for Object

created?integer

Parameter description for Created

model?string

Model ID used

choices?array

Parameter description for Choices

usage?object

Parameter description for Usage

prompt_tokens?integer

Parameter description for Prompt Tokens

completion_tokens?integer

Parameter description for Completion Tokens

total_tokens?integer

Parameter description for Total Tokens

prompt_tokens_details?object

Parameter description for Prompt Tokens Details

completion_tokens_details?object

Parameter description for Completion Tokens Details

system_fingerprint?string

Parameter description for System Fingerprint

400apiDocs.responses.badRequestParams

error?object

Parameter description for Error

message?string

Error Message

type?string

Error Type

param?string

Related Parameters

code?string

Error Code

429apiDocs.responses.rateLimited

error?object

Parameter description for Error

message?string

Error Message

type?string

Error Type

param?string

Related Parameters

code?string

Error Code

curl -X POST "https://api.modelstream.ai/v1/chat/completions" \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.4-pro",
  "instructions": "You are a senior software architect.",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Analyze this diagram and suggest improvements for scalability."
        },
        {
          "type": "input_image",
          "image_url": "https://example.com/arch.png",
          "detail": "high"
        }
      ]
    }
  ],
  "reasoning": {
    "effort": "medium",
    "summary": "auto"
  },
  "max_output_tokens": 4096,
  "text": {
    "verbosity": "medium"
  },
  "store": true,
  "metadata": {
    "topic": "architecture",
    "source": "modelstream"
  },
  "background": false,
  "stream": true
}'

{
  "id": "string",
  "object": "chat.completion",
  "created": 0,
  "model": "string",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "system",
        "content": null,
        "name": "string",
        "tool_calls": [
          {
            "id": "string",
            "type": "function",
            "function": {
              "name": "string",
              "arguments": "string"
            }
          }
        ],
        "tool_call_id": "string",
        "reasoning_content": "string"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 0,
    "completion_tokens": 0,
    "total_tokens": 0,
    "prompt_tokens_details": {
      "cached_tokens": 0,
      "text_tokens": 0,
      "audio_tokens": 0,
      "image_tokens": 0
    },
    "completion_tokens_details": {
      "text_tokens": 0,
      "audio_tokens": 0,
      "reasoning_tokens": 0
    }
  },
  "system_fingerprint": "string"
}

API Documentation

API Reference

Chat

Create Chat Completion

Supported Model Code

Loading models...

GPT-5.4 pro (gpt-5.4-pro)

gpt-5.4-pro0 models support this endpoint

Create chat completion

https://api.modelstream.ai

POST/v1/chat/completions

Authentication

BearerAuth

AuthenticationBearer <token>

All API requests must be authenticated using a Bearer token in the Authorization header. Please ensure your API key is active.Authorization: Bearer sk-xxxxxx

Parameter Location: Header Param

Request Body

application/json

These parameters come from the selected model form_schema. Switching models updates this list and the request example.

system_prompt?string

Top-level `instructions` for the Responses API; sets global model behavior.

Example Value: You are a helpful and expert assistant.Placeholder: e.g., You are a senior software architect...

prompt*string

RequiredExample Value: Hello! What can you do?Placeholder: Enter your question or instructions...

image_urls?array

Supports multi-image understanding (optional).

Value Range: 0 ≤ value ≤ 10

image_detail?string

Example Value: auto

Enum/Options:

Auto: autoLow: lowHigh: high

reasoning_effort?string

Controls how much reasoning effort the model spends before answering.

Example Value: medium

Enum/Options:

Medium: mediumHigh: highxHigh: xhigh

reasoning_summary?string

Returns a summary of the model reasoning process (Responses-only).

Example Value: auto

Enum/Options:

Auto: autoDetailed: detailed

verbosity?string

Controls how verbose the response is.

Example Value: medium

Enum/Options:

Low: lowMedium: mediumHigh: high

max_output_tokens?number

Example Value: 8192Value Range: 1 ≤ value ≤ 128000

response_format?string

Example Value: text

Enum/Options:

Text: textJSON Object: json_object

store?boolean

Whether to store this response for later retrieval (defaults on for Responses).

Example Value: true

topic?string

Written to metadata.topic for dashboard filtering (Responses-only).

Example Value: general

background?boolean

Run the response asynchronously in the background (for Pro models).

Example Value: false

stream?boolean

Example Value: true

Response Parameters

application/json

200apiDocs.responses.successCreateResponse

id?string

Parameter description for Id

object?string

Parameter description for Object

created?integer

Parameter description for Created

model?string

Model ID used

choices?array

Parameter description for Choices

usage?object

Parameter description for Usage

prompt_tokens?integer

Parameter description for Prompt Tokens

completion_tokens?integer

Parameter description for Completion Tokens

total_tokens?integer

Parameter description for Total Tokens

prompt_tokens_details?object

Parameter description for Prompt Tokens Details

completion_tokens_details?object

Parameter description for Completion Tokens Details

system_fingerprint?string

Parameter description for System Fingerprint

400apiDocs.responses.badRequestParams

error?object

Parameter description for Error

message?string

Error Message

type?string

Error Type

param?string

Related Parameters

code?string

Error Code

429apiDocs.responses.rateLimited

error?object

Parameter description for Error

message?string

Error Message

type?string

Error Type

param?string

Related Parameters

code?string

Error Code

curl -X POST "https://api.modelstream.ai/v1/chat/completions" \
  -H "Authorization: Bearer <token>" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.4-pro",
  "instructions": "You are a senior software architect.",
  "input": [
    {
      "type": "message",
      "role": "user",
      "content": [
        {
          "type": "input_text",
          "text": "Analyze this diagram and suggest improvements for scalability."
        },
        {
          "type": "input_image",
          "image_url": "https://example.com/arch.png",
          "detail": "high"
        }
      ]
    }
  ],
  "reasoning": {
    "effort": "medium",
    "summary": "auto"
  },
  "max_output_tokens": 4096,
  "text": {
    "verbosity": "medium"
  },
  "store": true,
  "metadata": {
    "topic": "architecture",
    "source": "modelstream"
  },
  "background": false,
  "stream": true
}'

{
  "id": "string",
  "object": "chat.completion",
  "created": 0,
  "model": "string",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "system",
        "content": null,
        "name": "string",
        "tool_calls": [
          {
            "id": "string",
            "type": "function",
            "function": {
              "name": "string",
              "arguments": "string"
            }
          }
        ],
        "tool_call_id": "string",
        "reasoning_content": "string"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 0,
    "completion_tokens": 0,
    "total_tokens": 0,
    "prompt_tokens_details": {
      "cached_tokens": 0,
      "text_tokens": 0,
      "audio_tokens": 0,
      "image_tokens": 0
    },
    "completion_tokens_details": {
      "text_tokens": 0,
      "audio_tokens": 0,
      "reasoning_tokens": 0
    }
  },
  "system_fingerprint": "string"
}

GPT-5.4 pro - Create Chat Completion (AI Model · By ) | ModelStream