> ## Documentation Index > Fetch the complete documentation index at: https://docs.aihubmax.com/llms.txt > Use this file to discover all available pages before exploring further. # OpenAI Format - Tool Calling Chat > - Generic Chat Completions API reference with tool calling for all OpenAI-compatible models - Supports Function Calling: define tools the model can invoke - Structured output: supports JSON Object / JSON Schema format - Multimodal input: supports text + image mixed input - Supports streaming and non-streaming responses ## OpenAPI ````yaml openapi/en/openai-format-chat-completions.json POST /v1/chat/completions openapi: 3.1.0 info: title: OpenAI Format - Tool Calling Chat version: '1.0' servers: - url: https://api.aihubmax.com security: - BearerAuth: [] paths: /v1/chat/completions: post: tags: - Text Series > OpenAI Format summary: OpenAI Format - Tool Calling Chat description: > - Generic Chat Completions API reference with tool calling for all OpenAI-compatible models - Supports Function Calling: define tools the model can invoke - Structured output: supports JSON Object / JSON Schema format - Multimodal input: supports text + image mixed input - Supports streaming and non-streaming responses operationId: openai-format-chat-completions requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ChatCompletionRequest' examples: single-turn: summary: Single Turn description: Basic single-turn Q&A value: model: gpt-5.4 messages: - role: user content: Write a quicksort algorithm in Python multi-turn: summary: Multi-turn description: Multi-turn conversation with context value: model: gpt-5.4 messages: - role: system content: You are a senior backend engineer - role: user content: >- My API response time increased from 200ms to 2s. What could be the cause? - role: assistant content: >- A significant increase in response time usually has several common causes: 1. Slow database queries (missing indexes, data growth) 2. External service call timeouts 3. Memory leaks causing frequent GC 4. Increased network latency Can you provide more details? Is it all endpoints or specific ones? - role: user content: Only the user list query endpoint is slow streaming: summary: Streaming description: Enable streaming for real-time content generation value: model: gpt-5.4 messages: - role: user content: Explain the TCP three-way handshake in detail stream: true with-image: summary: With Image description: Send an image for model analysis (vision) value: model: gpt-5.4 messages: - role: user content: - type: text text: >- What issues do you see in this architecture diagram? Point out potential performance bottlenecks - type: image_url image_url: url: >- https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cat03.jpg/1200px-Cat03.jpg tool-calling-weather: summary: Tool Use - Weather description: >- Let the model call a weather tool to get real-time weather info value: model: gpt-5.4 messages: - role: user content: >- What's the weather like in Tokyo today? Is it good for outdoor running? tools: - type: function function: name: get_weather description: Get current weather for a specified city parameters: type: object properties: city: type: string description: City name unit: type: string enum: - celsius - fahrenheit description: Temperature unit required: - city tool-calling-search: summary: Tool Use - Web Search description: Let the model call a search tool to find latest information value: model: gpt-5.4 messages: - role: user content: Search for the latest news about GPT-5 release tools: - type: function function: name: web_search description: Search the internet for information parameters: type: object properties: query: type: string description: Search keywords num_results: type: integer description: Number of results to return default: 5 required: - query tool-calling-database: summary: Tool Use - Data Query description: Let the model call a data query tool to retrieve business data value: model: gpt-5.4 messages: - role: user content: Find the top 5 products by sales last month tools: - type: function function: name: query_database description: Query the business database for data parameters: type: object properties: query: type: string description: SQL query database: type: string enum: - sales - inventory - users description: Target database required: - query - database responses: '200': $ref: '#/components/responses/ChatCompletionSuccess' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/PaymentRequired' '403': $ref: '#/components/responses/Forbidden' '429': $ref: '#/components/responses/TooManyRequests' '500': $ref: '#/components/responses/InternalServerError' components: schemas: ChatCompletionRequest: type: object required: - model - messages properties: model: type: string description: Model name, e.g. gpt-5.4, deepseek-chat, etc. example: gpt-5.4 messages: type: array description: List of messages in the conversation items: type: object required: - role - content properties: role: type: string description: Role of the message sender enum: - system - user - assistant - tool content: type: string description: Content of the message (string or array of content parts) stream: type: boolean description: Whether to stream the response default: false temperature: type: number description: Sampling temperature (0-2) minimum: 0 maximum: 2 max_tokens: type: integer description: Maximum number of tokens to generate top_p: type: number description: Nucleus sampling parameter (0-1) minimum: 0 maximum: 1 frequency_penalty: type: number description: >- Penalize new tokens based on their frequency in the text so far (-2 to 2) minimum: -2 maximum: 2 presence_penalty: type: number description: >- Penalize new tokens based on whether they appear in the text so far (-2 to 2) minimum: -2 maximum: 2 tools: type: array description: A list of tools the model may call items: type: object properties: type: type: string enum: - function function: type: object properties: name: type: string description: The name of the function to call description: type: string description: A description of what the function does parameters: type: object description: >- The parameters the function accepts, described as a JSON Schema object required: - name tool_choice: description: Controls which tool is called by the model oneOf: - type: string enum: - none - auto - required - type: object properties: type: type: string enum: - function function: type: object properties: name: type: string required: - name response_format: type: object description: An object specifying the format that the model must output properties: type: type: string description: The type of response format enum: - text - json_object - json_schema stop: description: Up to 4 sequences where the API will stop generating further tokens oneOf: - type: string - type: array items: type: string 'n': type: integer description: How many chat completion choices to generate for each input message ChatCompletionResponse: type: object properties: id: type: string description: Unique completion ID example: chatcmpl-abc123 object: type: string description: Object type enum: - chat.completion created: type: integer description: Creation timestamp example: 1757165031 model: type: string description: Model used choices: type: array items: type: object properties: index: type: integer description: Choice index example: 0 message: type: object properties: role: type: string example: assistant content: type: string example: Hello! How can I help you today? finish_reason: type: string description: Reason the generation stopped enum: - stop - length - content_filter - tool_calls example: stop usage: type: object properties: prompt_tokens: type: integer description: Number of tokens in the prompt example: 20 completion_tokens: type: integer description: Number of tokens in the completion example: 50 total_tokens: type: integer description: Total number of tokens used example: 70 ErrorResponse400: type: object properties: error: type: object properties: message: type: string example: Invalid request parameters type: type: string example: invalid_request_error ErrorResponse401: type: object properties: error: type: object properties: message: type: string example: Invalid API key type: type: string example: authentication_error ErrorResponse403: type: object properties: error: type: object properties: message: type: string example: Access denied type: type: string example: permission_error ErrorResponse429: type: object properties: error: type: object properties: message: type: string example: Rate limit exceeded type: type: string example: rate_limit_error ErrorResponse500: type: object properties: error: type: object properties: message: type: string example: Internal server error type: type: string example: server_error responses: ChatCompletionSuccess: description: Chat completion response content: application/json: schema: $ref: '#/components/schemas/ChatCompletionResponse' BadRequest: description: Bad Request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse400' Unauthorized: description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse401' PaymentRequired: description: Insufficient balance content: application/json: schema: $ref: '#/components/schemas/ErrorResponse400' Forbidden: description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorResponse403' TooManyRequests: description: Too Many Requests content: application/json: schema: $ref: '#/components/schemas/ErrorResponse429' InternalServerError: description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse500' securitySchemes: BearerAuth: type: http scheme: bearer description: | ## All APIs require Bearer Token authentication ## Add to request header: `Authorization: Bearer YOUR_API_KEY` ````