{ "openapi": "3.1.0", "info": { "title": "Pareto API", "version": "1", "summary": "OpenAI-compatible chat completions and Anthropic-compatible messages for Pareto, the model from Unbiased.", "description": "Pareto is served at https://api.unbiased.ai/v1. It accepts OpenAI Chat Completions requests at POST /chat/completions and Anthropic Messages requests at POST /messages. Send the model string `pareto`. This spec documents the core fields; the API follows the OpenAI and Anthropic request formats, so existing clients work by changing the base URL, key and model string.\n\nAuthentication: an API key from a platform.unbiased.ai account, sent as `Authorization: Bearer ` or in the `x-api-key` header.\n\nRate limits are per account and depend on the plan: Personal 20 requests per minute and 25M tokens a week, Personal Max 60 requests per minute and 300M tokens a week, Team 300 requests per minute with no weekly token cap. Requests over the limit return HTTP 429.\n\nKnown gaps during the private beta: GET /models is not implemented, and unknown model ids are not rejected yet, so always send `pareto` explicitly.\n\nVersioning: the major version is in the URL path (/v1). Product changes are announced at https://unbiased.ai/changelog/.\n\nHuman-readable docs: https://unbiased.ai/developers/", "termsOfService": "https://unbiased.ai/terms/", "contact": { "name": "Unbiased", "url": "https://unbiased.ai/contact/", "email": "info@unbiased.ai" } }, "externalDocs": { "description": "Developer docs, including examples and agent setup instructions", "url": "https://unbiased.ai/developers/" }, "servers": [ { "url": "https://api.unbiased.ai/v1", "description": "Production" } ], "security": [ { "bearerAuth": [] }, { "apiKeyHeader": [] } ], "tags": [ { "name": "OpenAI-compatible", "description": "OpenAI Chat Completions format" }, { "name": "Anthropic-compatible", "description": "Anthropic Messages format" } ], "paths": { "/chat/completions": { "post": { "operationId": "createChatCompletion", "summary": "Create a chat completion", "description": "Send a conversation in the OpenAI Chat Completions format and get Pareto's reply. Set `stream: true` for server-sent events in the OpenAI streaming format.", "tags": [ "OpenAI-compatible" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ChatCompletionRequest" }, "example": { "model": "pareto", "messages": [ { "role": "user", "content": "Summarize this diff in one sentence." } ] } } } }, "responses": { "200": { "description": "The completion. With `stream: true`, a text/event-stream of chunks instead.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ChatCompletionResponse" } }, "text/event-stream": { "schema": { "type": "string", "description": "OpenAI-format streaming chunks, ending with `data: [DONE]`." } } } }, "400": { "$ref": "#/components/responses/OpenAIError" }, "401": { "$ref": "#/components/responses/OpenAIError" }, "429": { "$ref": "#/components/responses/OpenAIError" }, "500": { "$ref": "#/components/responses/OpenAIError" } } } }, "/messages": { "post": { "operationId": "createMessage", "summary": "Create a message", "description": "Send a conversation in the Anthropic Messages format and get Pareto's reply. Set `stream: true` for server-sent events in the Anthropic streaming format.", "tags": [ "Anthropic-compatible" ], "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/MessageRequest" }, "example": { "model": "pareto", "max_tokens": 1024, "messages": [ { "role": "user", "content": "Summarize this diff in one sentence." } ] } } } }, "responses": { "200": { "description": "The message. With `stream: true`, a text/event-stream of events instead.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/MessageResponse" } }, "text/event-stream": { "schema": { "type": "string", "description": "Anthropic-format streaming events." } } } }, "400": { "$ref": "#/components/responses/AnthropicError" }, "401": { "$ref": "#/components/responses/AnthropicError" }, "429": { "$ref": "#/components/responses/AnthropicError" }, "500": { "$ref": "#/components/responses/AnthropicError" } } } } }, "components": { "securitySchemes": { "bearerAuth": { "type": "http", "scheme": "bearer", "description": "API key from platform.unbiased.ai, sent as `Authorization: Bearer `." }, "apiKeyHeader": { "type": "apiKey", "in": "header", "name": "x-api-key", "description": "The same API key, sent in the `x-api-key` header." } }, "responses": { "OpenAIError": { "description": "Error in the OpenAI format. 400 invalid request, 401 missing or invalid key, 429 rate limit reached, 500 server error.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OpenAIError" }, "example": { "error": { "message": "Missing API key. Pass your key as \"Authorization: Bearer \" or in the \"x-api-key\" header.", "type": "invalid_request_error", "code": "invalid_api_key" } } } } }, "AnthropicError": { "description": "Error in the Anthropic format. 400 invalid request, 401 missing or invalid key, 429 rate limit reached, 500 server error.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/AnthropicError" }, "example": { "type": "error", "error": { "type": "authentication_error", "message": "Missing API key. Pass your key as \"Authorization: Bearer \" or in the \"x-api-key\" header." }, "request_id": "req_8c6a9414bfdbc805a4c3c92e80e70537" } } } } }, "schemas": { "Model": { "type": "string", "const": "pareto", "description": "The model string. Always send `pareto`." }, "ChatMessage": { "type": "object", "required": [ "role", "content" ], "properties": { "role": { "type": "string", "enum": [ "system", "developer", "user", "assistant", "tool" ] }, "content": { "description": "Text, or an array of OpenAI content parts.", "oneOf": [ { "type": "string" }, { "type": "array", "items": { "type": "object" } } ] } } }, "ChatCompletionRequest": { "type": "object", "required": [ "model", "messages" ], "properties": { "model": { "$ref": "#/components/schemas/Model" }, "messages": { "type": "array", "minItems": 1, "items": { "$ref": "#/components/schemas/ChatMessage" } }, "stream": { "type": "boolean", "default": false }, "max_tokens": { "type": "integer", "minimum": 1 }, "temperature": { "type": "number", "minimum": 0, "maximum": 2 }, "tools": { "type": "array", "items": { "type": "object" }, "description": "Tool definitions in the OpenAI format." } } }, "ChatCompletionResponse": { "type": "object", "required": [ "id", "object", "choices" ], "properties": { "id": { "type": "string" }, "object": { "type": "string", "const": "chat.completion" }, "created": { "type": "integer" }, "model": { "type": "string" }, "choices": { "type": "array", "items": { "type": "object", "properties": { "index": { "type": "integer" }, "message": { "$ref": "#/components/schemas/AssistantMessage" }, "finish_reason": { "type": [ "string", "null" ] } } } }, "usage": { "type": "object", "properties": { "prompt_tokens": { "type": "integer" }, "completion_tokens": { "type": "integer" }, "total_tokens": { "type": "integer" } } } } }, "MessageRequest": { "type": "object", "required": [ "model", "max_tokens", "messages" ], "properties": { "model": { "$ref": "#/components/schemas/Model" }, "max_tokens": { "type": "integer", "minimum": 1 }, "system": { "description": "System prompt as text or an array of text blocks.", "oneOf": [ { "type": "string" }, { "type": "array", "items": { "type": "object" } } ] }, "messages": { "type": "array", "minItems": 1, "items": { "type": "object", "required": [ "role", "content" ], "properties": { "role": { "type": "string", "enum": [ "user", "assistant" ] }, "content": { "oneOf": [ { "type": "string" }, { "type": "array", "items": { "type": "object" } } ] } } } }, "stream": { "type": "boolean", "default": false }, "temperature": { "type": "number", "minimum": 0, "maximum": 1 }, "tools": { "type": "array", "items": { "type": "object" }, "description": "Tool definitions in the Anthropic format." } } }, "MessageResponse": { "type": "object", "required": [ "id", "type", "role", "content" ], "properties": { "id": { "type": "string" }, "type": { "type": "string", "const": "message" }, "role": { "type": "string", "const": "assistant" }, "model": { "type": "string" }, "content": { "type": "array", "items": { "type": "object" } }, "stop_reason": { "type": [ "string", "null" ] }, "usage": { "type": "object", "properties": { "input_tokens": { "type": "integer" }, "output_tokens": { "type": "integer" } } } } }, "OpenAIError": { "type": "object", "required": [ "error" ], "properties": { "error": { "type": "object", "required": [ "message", "type" ], "properties": { "message": { "type": "string", "description": "Human-readable explanation." }, "type": { "type": "string", "description": "Error category, for example invalid_request_error." }, "code": { "type": [ "string", "null" ], "description": "Machine-readable code, for example invalid_api_key." } } } } }, "AnthropicError": { "type": "object", "required": [ "type", "error" ], "properties": { "type": { "type": "string", "const": "error" }, "error": { "type": "object", "required": [ "type", "message" ], "properties": { "type": { "type": "string", "description": "Error category, for example authentication_error." }, "message": { "type": "string", "description": "Human-readable explanation." } } }, "request_id": { "type": "string" } } }, "AssistantMessage": { "type": "object", "required": [ "role" ], "properties": { "role": { "type": "string", "const": "assistant" }, "content": { "type": [ "string", "null" ], "description": "Reply text; null when the reply is only tool calls." }, "tool_calls": { "type": "array", "items": { "type": "object" }, "description": "Tool calls in the OpenAI format." } } } } } }