> ## Documentation Index > Fetch the complete documentation index at: https://gomodel-docs-benchmark-writeup-and-tooling.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Create a message (Anthropic Messages API) ## OpenAPI ````yaml /openapi.json post /v1/messages openapi: 3.0.0 info: description: >- AI gateway routing requests to multiple LLM providers (OpenAI, Anthropic, Gemini, Groq, OpenRouter, DeepSeek, Z.ai, xAI, MiniMax, Xiaomi MiMo, OpenCode Go, Oracle, Ollama, Bailian). Drop-in OpenAI-compatible API. title: GoModel API contact: {} version: '1.0' servers: - url: '{base_url}' description: Edit the base URL to point at your GoModel deployment. variables: base_url: default: http://localhost:8080 description: Your GoModel deployment URL security: [] paths: /v1/messages: post: tags: - messages summary: Create a message (Anthropic Messages API) requestBody: $ref: '#/components/requestBodies/anthropicapi.MessagesRequest' responses: '200': description: JSON response or SSE stream when stream=true content: application/json: schema: $ref: '#/components/schemas/anthropicapi.MessagesResponse' text/event-stream: schema: $ref: '#/components/schemas/anthropicapi.SSEEventFrame' '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' text/event-stream: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' text/event-stream: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' '429': description: Too Many Requests content: application/json: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' text/event-stream: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' '502': description: Bad Gateway content: application/json: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' text/event-stream: schema: $ref: '#/components/schemas/anthropicapi.ErrorResponse' security: - BearerAuth: [] components: requestBodies: anthropicapi.MessagesRequest: content: application/json: schema: $ref: '#/components/schemas/anthropicapi.MessagesRequest' description: Anthropic Messages request required: true schemas: anthropicapi.MessagesResponse: type: object properties: content: type: array items: $ref: '#/components/schemas/anthropicapi.ResponseContentBlock' id: type: string model: type: string role: type: string stop_reason: type: string stop_sequence: type: string type: type: string usage: $ref: '#/components/schemas/anthropicapi.Usage' anthropicapi.SSEEventFrame: description: >- One server-sent event frame emitted by streaming /v1/messages. On the wire each frame is sent as event: and data: . Unknown event payloads are accepted for forward compatibility. anyOf: - $ref: '#/components/schemas/anthropicapi.SSEMessageStartEvent' - $ref: '#/components/schemas/anthropicapi.SSEContentBlockStartEvent' - $ref: '#/components/schemas/anthropicapi.SSEContentBlockDeltaEvent' - $ref: '#/components/schemas/anthropicapi.SSEContentBlockStopEvent' - $ref: '#/components/schemas/anthropicapi.SSEMessageDeltaEvent' - $ref: '#/components/schemas/anthropicapi.SSEMessageStopEvent' - $ref: '#/components/schemas/anthropicapi.SSEPingEvent' - $ref: '#/components/schemas/anthropicapi.SSEErrorEvent' - $ref: '#/components/schemas/anthropicapi.SSEUnknownEvent' anthropicapi.ErrorResponse: type: object properties: error: $ref: '#/components/schemas/anthropicapi.ErrorObject' type: type: string anthropicapi.MessagesRequest: type: object properties: max_tokens: type: integer messages: type: array items: $ref: '#/components/schemas/anthropicapi.Message' metadata: $ref: '#/components/schemas/anthropicapi.Metadata' model: type: string stop_sequences: type: array items: type: string stream: type: boolean system: oneOf: - type: string - type: array items: $ref: '#/components/schemas/anthropicapi.ContentBlock' temperature: type: number thinking: $ref: '#/components/schemas/anthropicapi.Thinking' tool_choice: $ref: '#/components/schemas/anthropicapi.ToolChoice' tools: type: array items: $ref: '#/components/schemas/anthropicapi.Tool' top_k: type: integer top_p: type: number anthropicapi.ResponseContentBlock: type: object properties: id: type: string input: type: object additionalProperties: true name: type: string text: type: string thinking: type: string type: type: string anthropicapi.Usage: type: object properties: cache_creation_input_tokens: type: integer cache_read_input_tokens: type: integer input_tokens: type: integer output_tokens: type: integer anthropicapi.SSEMessageStartEvent: type: object required: - message - type properties: type: type: string enum: - message_start message: $ref: '#/components/schemas/anthropicapi.MessagesResponse' anthropicapi.SSEContentBlockStartEvent: type: object required: - content_block - index - type properties: type: type: string enum: - content_block_start index: type: integer content_block: $ref: '#/components/schemas/anthropicapi.ResponseContentBlock' anthropicapi.SSEContentBlockDeltaEvent: type: object required: - delta - index - type properties: type: type: string enum: - content_block_delta index: type: integer delta: type: object additionalProperties: true anthropicapi.SSEContentBlockStopEvent: type: object required: - index - type properties: type: type: string enum: - content_block_stop index: type: integer anthropicapi.SSEMessageDeltaEvent: type: object required: - delta - type properties: type: type: string enum: - message_delta delta: type: object additionalProperties: true usage: $ref: '#/components/schemas/anthropicapi.Usage' anthropicapi.SSEMessageStopEvent: type: object required: - type properties: type: type: string enum: - message_stop anthropicapi.SSEPingEvent: type: object required: - type properties: type: type: string enum: - ping anthropicapi.SSEErrorEvent: type: object required: - error - type properties: type: type: string enum: - error error: $ref: '#/components/schemas/anthropicapi.ErrorObject' anthropicapi.SSEUnknownEvent: description: Fallback for future Anthropic streaming event payloads. type: object required: - type properties: type: type: string additionalProperties: true anthropicapi.ErrorObject: type: object properties: message: type: string type: type: string anthropicapi.Message: type: object properties: content: oneOf: - type: string - type: array items: $ref: '#/components/schemas/anthropicapi.ContentBlock' role: type: string anthropicapi.Metadata: type: object properties: user_id: type: string anthropicapi.ContentBlock: type: object properties: content: oneOf: - type: string - type: array items: $ref: '#/components/schemas/anthropicapi.ContentBlock' id: type: string input: type: object additionalProperties: true is_error: type: boolean name: type: string source: oneOf: - type: string - type: object additionalProperties: true text: type: string thinking: type: string tool_use_id: type: string type: type: string anthropicapi.Thinking: type: object properties: budget_tokens: type: integer type: type: string anthropicapi.ToolChoice: type: object properties: disable_parallel_tool_use: type: boolean name: type: string type: type: string anthropicapi.Tool: type: object properties: description: type: string input_schema: type: object additionalProperties: true name: type: string type: type: string securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: JWT ````