> ## Documentation Index > Fetch the complete documentation index at: https://docs.cubeuaeai.com/llms.txt > Use this file to discover all available pages before exploring further. # Create Message > Send a structured list of input messages, and the model will generate the next message in the conversation. ## OpenAPI ````yaml en/api-reference/endpoints/openapi/anthropic/openapi.yaml POST /v1/messages openapi: 3.1.0 info: title: Anthropic Claude-compatible endpoint description: Call the native Anthropic Messages API. All Claude models are supported version: 1.0.0 servers: - url: https://ai.cubeuaeai.com security: - bearerAuth: [] paths: /v1/messages: post: summary: Create a message description: >- Send a list of structured input messages. The model generates the next message in the conversation. operationId: createMessage requestBody: required: true content: application/json: schema: type: object required: - model - max_tokens - messages properties: model: type: string enum: - claude-sonnet-4-6 - claude-sonnet-4-5-20250929 - claude-sonnet-4-20250514 - claude-opus-4-6 - claude-opus-4-5-20251101 - claude-opus-4-1-20250805 - claude-opus-4-20250514 - claude-haiku-4-5-20251001 - claude-3-7-sonnet-20250219 - claude-3-5-sonnet-20241022 description: The model used for completion. example: claude-sonnet-4-6 messages: type: array minItems: 1 description: >- List of input messages. Each message includes a role and content. items: type: object required: - role - content properties: role: type: string enum: - user - assistant description: Role of the message author. content: oneOf: - type: string - type: array items: type: object properties: type: type: string enum: - text - image text: type: string source: type: object properties: type: type: string media_type: type: string data: type: string description: >- Message content. Can be a string or an array of content blocks. example: - role: user content: Hello, Claude! max_tokens: type: integer minimum: 1 description: Maximum number of tokens to generate before stopping. example: 1024 system: oneOf: - type: string - type: array items: type: object properties: type: type: string text: type: string description: System prompt. Provides context and instructions for Claude. metadata: type: object properties: user_id: type: string description: >- An external identifier for the user associated with the request. description: An object that describes request metadata. stop_sequences: type: array items: type: string description: >- Custom text sequences. The model stops generating when it encounters them. temperature: type: number minimum: 0 maximum: 1 default: 1 description: 'Randomness injected into the response. Range: 0.0 to 1.0.' example: 1 top_p: type: number minimum: 0 maximum: 1 description: >- Use nucleus sampling. Prefer either temperature or top_p, not both. top_k: type: integer minimum: 0 description: >- Sample only from the top K options for each subsequent token. stream: type: boolean default: false description: >- Whether to incrementally stream the response using server-sent events (SSE). tools: type: array items: type: object required: - name - input_schema properties: name: type: string description: Tool name. description: type: string description: Description of what the tool does. input_schema: type: object description: JSON Schema for the tool input. description: Tool definitions the model can use. tool_choice: type: object properties: type: type: string enum: - auto - any - tool description: How the model uses the provided tools. name: type: string description: Name of the tool to use (when type is "tool"). description: Controls how the model uses the provided tools. thinking: type: object properties: type: type: string enum: - enabled - disabled description: Whether to enable extended thinking. budget_tokens: type: integer minimum: 1024 description: Maximum number of tokens used for thinking. description: >- Extended thinking configuration. When enabled, the model thinks deeply before replying. responses: '200': description: Message created successfully content: application/json: schema: $ref: '#/components/schemas/Message' '400': description: Invalid request content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: Message: type: object required: - id - type - role - content - model - stop_reason - usage properties: id: type: string example: msg_01XFDUDYJgAACzvnptvVoYEL type: type: string example: message role: type: string example: assistant content: type: array items: type: object properties: type: type: string enum: - text - thinking - tool_use text: type: string thinking: type: string id: type: string name: type: string input: type: object example: - type: text text: Hello! How can I help you? model: type: string example: claude-sonnet-4-6 stop_reason: type: string enum: - end_turn - max_tokens - stop_sequence - tool_use - null stop_sequence: type: string nullable: true usage: type: object properties: input_tokens: type: integer output_tokens: type: integer cache_creation_input_tokens: type: integer cache_read_input_tokens: type: integer Error: type: object properties: type: type: string example: error error: type: object properties: type: type: string message: type: string securitySchemes: bearerAuth: type: http scheme: bearer ````