Message Formats

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import { OpenRouter, fromChatMessages } from '@openrouter/sdk';
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const openrouter = new OpenRouter({
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  apiKey: process.env.OPENROUTER_API_KEY,
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});
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// OpenAI chat format
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const chatMessages = [
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  { role: 'system', content: 'You are a helpful assistant.' },
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  { role: 'user', content: 'Hello!' },
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  { role: 'assistant', content: 'Hi there! How can I help you?' },
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  { role: 'user', content: 'What is the weather like?' },
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];
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const result = openrouter.callModel({
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  model: 'openai/gpt-5-nano',
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  input: fromChatMessages(chatMessages),
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});
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const text = await result.getText();

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import { toChatMessage } from '@openrouter/sdk';
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const result = openrouter.callModel({
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  model: 'openai/gpt-5-nano',
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  input: 'Hello!',
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});
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const response = await result.getResponse();
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const chatMessage = toChatMessage(response);
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// chatMessage is now: { role: 'assistant', content: '...' }
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console.log(chatMessage.role);    // 'assistant'
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console.log(chatMessage.content); // Response text

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const chatMessages = [
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  { role: 'user', content: 'What is the weather?' },
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  {
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    role: 'assistant',
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    content: null,
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    tool_calls: [{
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      id: 'call_123',
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      type: 'function',
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      function: { name: 'get_weather', arguments: '{"location":"Paris"}' },
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    }],
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  },
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  {
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    role: 'tool',
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    tool_call_id: 'call_123',
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    content: '{"temperature": 20}',
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  },
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];
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const input = fromChatMessages(chatMessages);

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import { OpenRouter, fromClaudeMessages } from '@openrouter/sdk';
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// Claude format
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const claudeMessages = [
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  { role: 'user', content: 'Hello!' },
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  { role: 'assistant', content: 'Hi there!' },
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  { role: 'user', content: 'Tell me about TypeScript.' },
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];
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const result = openrouter.callModel({
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  model: 'anthropic/claude-sonnet-4.5',
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  input: fromClaudeMessages(claudeMessages),
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});

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import { toClaudeMessage } from '@openrouter/sdk';
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const result = openrouter.callModel({
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  model: 'anthropic/claude-sonnet-4.5',
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  input: 'Hello!',
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});
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const response = await result.getResponse();
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const claudeMessage = toClaudeMessage(response);
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// Compatible with Anthropic SDK types

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const claudeMessages = [
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  {
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    role: 'user',
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    content: [
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      { type: 'text', text: 'What is in this image?' },
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      {
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        type: 'image',
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        source: {
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          type: 'url',
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          url: 'https://example.com/image.jpg',
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        },
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      },
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    ],
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  },
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];
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const input = fromClaudeMessages(claudeMessages);

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const claudeMessages = [
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  { role: 'user', content: 'What is the weather?' },
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  {
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    role: 'assistant',
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    content: [
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      {
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        type: 'tool_use',
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        id: 'tool_123',
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        name: 'get_weather',
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        input: { location: 'Paris' },
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      },
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    ],
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  },
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  {
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    role: 'user',
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    content: [
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      {
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        type: 'tool_result',
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        tool_use_id: 'tool_123',
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        content: '{"temperature": 20}',
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      },
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    ],
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  },
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];
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const input = fromClaudeMessages(claudeMessages);

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const claudeMessages = [
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  {
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    role: 'user',
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    content: [
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      { type: 'text', text: 'Describe this image.' },
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      {
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        type: 'image',
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        source: {
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          type: 'base64',
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          media_type: 'image/png',
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          data: 'iVBORw0KGgo...',
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        },
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      },
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    ],
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  },
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];

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// Before: OpenAI SDK
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import OpenAI from 'openai';
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const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
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const completion = await openai.chat.completions.create({
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  model: 'gpt-4',
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  messages: [
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    { role: 'system', content: 'You are helpful.' },
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    { role: 'user', content: 'Hello!' },
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  ],
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});
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// After: OpenRouter SDK
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import { OpenRouter, fromChatMessages } from '@openrouter/sdk';
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const openrouter = new OpenRouter({ apiKey: process.env.OPENROUTER_API_KEY });
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const result = openrouter.callModel({
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  model: 'openai/gpt-5.2',
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  input: fromChatMessages([
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    { role: 'system', content: 'You are helpful.' },
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    { role: 'user', content: 'Hello!' },
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  ]),
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});
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const text = await result.getText();

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// Before: Anthropic SDK
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import Anthropic from '@anthropic-ai/sdk';
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const anthropic = new Anthropic();
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const message = await anthropic.messages.create({
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  model: 'claude-sonnet-4-20250514',
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  max_tokens: 1024,
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  messages: [
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    { role: 'user', content: 'Hello!' },
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  ],
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});
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// After: OpenRouter SDK
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import { OpenRouter, fromClaudeMessages } from '@openrouter/sdk';
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const openrouter = new OpenRouter({ apiKey: process.env.OPENROUTER_API_KEY });
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const result = openrouter.callModel({
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  model: 'anthropic/claude-sonnet-4.5',
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  input: fromClaudeMessages([
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    { role: 'user', content: 'Hello!' },
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  ]),
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  maxOutputTokens: 1024,
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});
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const text = await result.getText();

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import { fromChatMessages, toChatMessage } from '@openrouter/sdk';
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// Start with initial message
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let messages = [
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  { role: 'system', content: 'You are a helpful assistant.' },
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  { role: 'user', content: 'Hello!' },
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];
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// First call
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let result = openrouter.callModel({
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  model: 'openai/gpt-5-nano',
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  input: fromChatMessages(messages),
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});
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let response = await result.getResponse();
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let assistantMessage = toChatMessage(response);
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// Add to history
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messages.push(assistantMessage);
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messages.push({ role: 'user', content: 'What can you help me with?' });
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// Continue conversation
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result = openrouter.callModel({
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  model: 'openai/gpt-5-nano',
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  input: fromChatMessages(messages),
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});