> ## Documentation Index > Fetch the complete documentation index at: https://docs.getbifrost.ai/llms.txt > Use this file to discover all available pages before exploring further. # Create message (LangChain - Anthropic format) > Creates a message using Anthropic-compatible format via LangChain. ## OpenAPI ````yaml /openapi/openapi.json post /langchain/anthropic/v1/messages openapi: 3.1.0 info: title: Bifrost API description: > Bifrost HTTP Transport API for AI model inference and gateway management. This API provides a unified interface for interacting with multiple AI providers including OpenAI, Anthropic, Bedrock, Gemini, and more through a single API, along with comprehensive management APIs for configuring and monitoring the gateway. ## API Structure ### Unified Inference API (`/v1/*`) The primary API using Bifrost's unified format. Model parameters use the format `provider/model` (e.g., `openai/gpt-4`, `anthropic/claude-3-opus`). ### Async Inference API (`/v1/async/*`) Submit inference requests for asynchronous execution. Returns a job ID immediately and allows polling for results. Supports all inference types except batches, files, and containers. ### Provider Integration APIs Native provider-format APIs for drop-in compatibility: - `/openai/*` - OpenAI-compatible API - `/anthropic/*` - Anthropic-compatible API - `/genai/*` - Google GenAI (Gemini) compatible API - `/bedrock/*` - AWS Bedrock compatible API - `/cohere/*` - Cohere compatible API ### Framework Integration APIs Multi-provider proxy endpoints for AI frameworks: - `/litellm/*` - LiteLLM proxy with all provider formats - `/langchain/*` - LangChain compatible endpoints - `/pydanticai/*` - PydanticAI compatible endpoints ### Management APIs (`/api/*`) APIs for managing and monitoring the Bifrost gateway: - `/api/config` - Configuration management - `/api/providers` - Provider and API key management - `/api/plugins` - Plugin management - `/api/governance/*` - Virtual keys, teams, customers, budgets, rate limits, routing rules, and pricing overrides - `/api/logs` - Log search and analytics - `/api/mcp/*` - MCP (Model Context Protocol) client management - `/api/session/*` - Authentication and session management - `/api/cache/*` - Cache management - `/health` - Health check endpoint ## Fallbacks Requests can include fallback models that will be tried if the primary model fails. version: 1.0.0 contact: name: Contact Us url: https://getmaxim.ai/bifrost license: name: Apache 2.0 url: https://opensource.org/licenses/Apache-2.0 servers: - url: '{baseUrl}' description: Your Bifrost instance variables: baseUrl: default: http://localhost:8080 description: Base URL of your Bifrost instance (e.g. https://bifrost.mycompany.com) security: - BearerAuth: [] - BasicAuth: [] - ApiKeyAuth: [] tags: - name: Models description: Model listing and information - name: Chat Completions description: Chat-based text generation - name: Text Completions description: Text completion generation - name: Responses description: OpenAI Responses API compatible endpoints - name: OCR description: Optical character recognition for documents and images - name: Rerank description: Document reranking by relevance to a query - name: Embeddings description: Text embedding generation - name: Images description: Image generations, editing, and variations - name: Videos description: Video generation and management - name: Audio description: Speech synthesis and transcription - name: Count Tokens description: Token counting utilities - name: Batch description: Batch processing operations - name: Files description: File management operations - name: Containers description: Container management operations - name: Async Jobs description: Asynchronous job submission and retrieval endpoints - name: Realtime description: Realtime WebSocket and WebRTC endpoints - name: OpenAI Integration description: OpenAI-compatible API endpoints (/openai/*) - name: Azure Integration description: Azure OpenAI integration endpoints - name: Anthropic Integration description: Anthropic-compatible API endpoints (/anthropic/*) - name: GenAI Integration description: Google GenAI (Gemini) compatible API endpoints (/genai/*) - name: Bedrock Integration description: AWS Bedrock compatible API endpoints (/bedrock/*) - name: Cohere Integration description: Cohere compatible API endpoints (/cohere/*) - name: LiteLLM Integration description: LiteLLM proxy endpoints with multi-provider support (/litellm/*) - name: LangChain Integration description: LangChain compatible endpoints with multi-provider support (/langchain/*) - name: PydanticAI Integration description: >- PydanticAI compatible endpoints with multi-provider support (/pydanticai/*) - name: Health description: Health check endpoints - name: Configuration description: Configuration management endpoints - name: Session description: Session and authentication endpoints - name: Providers description: Provider management endpoints - name: Plugins description: Plugin management endpoints - name: MCP description: Model Context Protocol endpoints - name: Governance description: Virtual keys, teams, and customers management - name: Logging description: Log search and management endpoints - name: Cache description: Cache management endpoints paths: /langchain/anthropic/v1/messages: post: tags: - LangChain Integration summary: Create message (LangChain - Anthropic format) description: | Creates a message using Anthropic-compatible format via LangChain. operationId: langchainAnthropicMessages requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AnthropicMessageRequest' responses: '200': description: Successful response content: application/json: schema: $ref: '#/components/schemas/AnthropicMessageResponse' text/event-stream: schema: type: object properties: id: type: string type: type: string enum: - message_start - content_block_start - content_block_delta - content_block_stop - message_delta - message_stop - ping - error message: $ref: '#/components/schemas/AnthropicMessageResponse' index: type: integer content_block: $ref: '#/components/schemas/AnthropicContentBlock' delta: type: object properties: type: type: string enum: - text_delta - input_json_delta - thinking_delta - signature_delta text: type: string partial_json: type: string thinking: type: string signature: type: string stop_reason: type: string stop_sequence: type: string usage: type: object properties: input_tokens: type: integer output_tokens: type: integer cache_creation_input_tokens: type: integer cache_read_input_tokens: type: integer cache_creation: type: object properties: ephemeral_5m_input_tokens: type: integer ephemeral_1h_input_tokens: type: integer error: type: object properties: message: type: string type: type: string '400': description: Bad request content: application/json: schema: type: object properties: type: type: string default: error error: type: object properties: type: type: string description: Error type (e.g., invalid_request_error, api_error) message: type: string description: Error message '500': description: Internal server error content: application/json: schema: type: object properties: type: type: string default: error error: type: object properties: type: type: string description: Error type (e.g., invalid_request_error, api_error) message: type: string description: Error message security: - BearerAuth: [] - BasicAuth: [] - VirtualKeyAuth: [] - ApiKeyAuth: [] components: schemas: AnthropicMessageRequest: type: object required: - model - max_tokens - messages properties: model: type: string description: Model identifier (e.g., claude-3-opus-20240229) example: claude-3-opus-20240229 max_tokens: type: integer description: Maximum tokens to generate messages: type: array items: $ref: '#/components/schemas/AnthropicMessage' description: List of messages in the conversation system: oneOf: - type: string - type: array items: $ref: '#/components/schemas/AnthropicContentBlock' description: System prompt cache_control: $ref: '#/components/schemas/CacheControl' description: Automatic caching directives for the whole request metadata: type: object properties: user_id: type: string stream: type: boolean description: Whether to stream the response temperature: type: number minimum: 0 maximum: 1 top_p: type: number top_k: type: integer stop_sequences: type: array items: type: string tools: type: array items: type: object properties: type: type: string enum: - custom - bash_20250124 - computer_20250124 - computer_20251124 - code_execution_20250522 - code_execution_20250825 - code_execution_20260120 - text_editor_20250124 - text_editor_20250429 - text_editor_20250728 - web_search_20250305 - web_search_20260209 - web_fetch_20250910 - web_fetch_20260209 - web_fetch_20260309 - memory_20250818 - tool_search_tool_bm25 - tool_search_tool_bm25_20251119 - tool_search_tool_regex - tool_search_tool_regex_20251119 name: type: string description: Tool name (for custom tools) description: type: string input_schema: type: object description: JSON Schema for tool input cache_control: $ref: '#/components/schemas/CacheControl' display_width_px: type: integer display_height_px: type: integer display_number: type: integer enable_zoom: type: boolean max_uses: type: integer allowed_domains: type: array items: type: string blocked_domains: type: array items: type: string user_location: type: object properties: type: type: string enum: - approximate city: type: string country: type: string timezone: type: string tool_choice: oneOf: - type: object properties: type: type: string enum: - auto - any - tool - none name: type: string description: Required when type is 'tool' disable_parallel_tool_use: type: boolean mcp_servers: type: array items: type: object properties: type: type: string name: type: string url: type: string authorization_token: type: string description: Authorization token for the MCP server tool_configuration: type: object properties: enabled: type: boolean allowed_tools: type: array items: type: string description: MCP servers configuration (requires beta header) thinking: type: object properties: type: type: string enum: - enabled - disabled budget_tokens: type: integer output_format: type: object description: Structured output format (requires beta header) fallbacks: type: array items: type: string AnthropicMessageResponse: type: object properties: id: type: string type: type: string default: message role: type: string default: assistant content: type: array items: $ref: '#/components/schemas/AnthropicContentBlock' model: type: string stop_reason: type: string enum: - end_turn - max_tokens - stop_sequence - tool_use - pause_turn - refusal - model_context_window_exceeded - 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 cache_creation: type: object properties: ephemeral_5m_input_tokens: type: integer ephemeral_1h_input_tokens: type: integer AnthropicContentBlock: type: object required: - type properties: type: type: string enum: - text - image - document - tool_use - server_tool_use - tool_result - web_search_result - mcp_tool_use - mcp_tool_result - thinking - redacted_thinking text: type: string description: For text content thinking: type: string description: For thinking content signature: type: string description: For signature content data: type: string description: For data content (encrypted data for redacted thinking) tool_use_id: type: string description: For tool_result content id: type: string description: For tool_use content name: type: string description: For tool_use content input: type: object description: For tool_use content server_name: type: string description: For mcp_tool_use content content: oneOf: - type: string - type: array items: $ref: '#/components/schemas/AnthropicContentBlock' description: For tool_result content source: type: object required: - type properties: type: type: string enum: - base64 - url - text - content_block media_type: type: string description: MIME type (e.g., image/jpeg, application/pdf) data: type: string description: Base64-encoded data (for base64 type) url: type: string description: URL (for url type) description: For image/document content cache_control: $ref: '#/components/schemas/CacheControl' citations: type: object properties: enabled: type: boolean description: For document content context: type: string description: For document content title: type: string description: For document content AnthropicMessage: type: object required: - role - content properties: role: type: string enum: - user - assistant content: oneOf: - type: string - type: array items: $ref: '#/components/schemas/AnthropicContentBlock' description: Content - can be a string or array of content blocks CacheControl: type: object description: Cache control settings for content blocks properties: type: type: string enum: - ephemeral ttl: type: string description: Time to live (e.g., "1m", "1h") securitySchemes: BearerAuth: type: http scheme: bearer description: > Bearer token authentication. Use your provider API key or Bifrost authentication token. Virtual keys (prefixed with `sk-bf-`) can also be passed here. BasicAuth: type: http scheme: basic description: | Basic authentication using username and password. ApiKeyAuth: type: apiKey in: header name: x-api-key description: | API key authentication via the `x-api-key` header. Virtual keys (prefixed with `sk-bf-`) can also be passed here. VirtualKeyAuth: type: apiKey in: header name: x-bf-vk description: > Bifrost Virtual Key for governance, routing, and access control. Supported on all inference endpoints (`/v1/*`, `/openai/*`, `/anthropic/*`, `/bedrock/*`, `/cohere/*`, `/genai/*`, `/langchain/*`, `/litellm/*`, `/pydanticai/*`, `/mcp`), not on management APIs (`/api/*`). Example: `sk-bf-*` prefixed keys. ````