OpenRouter Provider - HAI Build Code Generator

OpenRouter provides access to multiple LLM providers through a single API, with automatic fallback, cost tracking, and model routing.

Configuration

string

required

Your OpenRouter API key from OpenRouter Dashboard

string

required

Model identifier in OpenRouter format. Examples:

anthropic/claude-4.5-sonnet
openai/gpt-4o
google/gemini-3.0-flash-thinking
deepseek/deepseek-reasoner
xai/grok-4

ModelInfo

Model metadata. OpenRouter fetches this automatically if not provided.

string

Provider preference order. Examples:

"anthropic,openai" - Prefer Anthropic, fallback to OpenAI
"google" - Use only Google

string

For reasoning models. Options: low, medium, high, xhigh

number

Token budget for extended thinking (model-dependent)

Basic Setup

import { OpenRouterHandler } from "./providers/openrouter"

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet"
})

Provider Routing

Control which providers handle your requests:

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-sonnet-4",
  openRouterProviderSorting: "anthropic,openrouter"
  // Try Anthropic first, fallback to OpenRouter's default
})

Reasoning Models

OpenRouter supports various reasoning models:

DeepSeek Reasoner

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "deepseek/deepseek-reasoner"
})

for await (const chunk of handler.createMessage(
  systemPrompt,
  messages,
  tools
)) {
  if (chunk.type === "reasoning") {
    console.log("Reasoning:", chunk.reasoning)
    
    // OpenRouter preserves reasoning_details for model
    if (chunk.details) {
      console.log("Details:", chunk.details)
    }
  }
}

Gemini with Thinking

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "google/gemini-3.0-flash-thinking",
  reasoningEffort: "high", // or "medium"
  thinkingBudgetTokens: 15000
})

Anthropic Extended Thinking

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-sonnet-4",
  thinkingBudgetTokens: 10000
})

Reasoning Details Preservation

OpenRouter passes reasoning_details for models to preserve reasoning traces:

for await (const chunk of handler.createMessage(...)) {
  if (chunk.type === "reasoning" && chunk.details) {
    // These details can be sent back to the API
    // to preserve reasoning context
    console.log("Reasoning details:", chunk.details)
  }
}

From openrouter.ts:133-146:

Reasoning block preservationOpenRouter returns reasoning_details in delta responses that should be preserved and sent back in subsequent API requests to maintain reasoning traces. See OpenRouter docs.

Tool Calling

import type { ChatCompletionTool } from "openai/resources/chat/completions"

const tools: ChatCompletionTool[] = [
  {
    type: "function",
    function: {
      name: "get_weather",
      description: "Get current weather",
      parameters: {
        type: "object",
        properties: {
          location: {
            type: "string",
            description: "City name"
          }
        },
        required: ["location"]
      }
    }
  }
]

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet"
})

for await (const chunk of handler.createMessage(
  systemPrompt,
  messages,
  tools
)) {
  if (chunk.type === "tool_calls") {
    console.log("Tool:", chunk.tool_call.function.name)
    console.log("Args:", chunk.tool_call.function.arguments)
  }
}

Cost Tracking

OpenRouter provides detailed cost information:

for await (const chunk of handler.createMessage(...)) {
  if (chunk.type === "usage") {
    console.log("Input tokens:", chunk.inputTokens)
    console.log("Output tokens:", chunk.outputTokens)
    console.log("Cached tokens:", chunk.cacheReadTokens)
    console.log("Total cost:", chunk.totalCost) // In USD
  }
}

Generation Endpoint Fallback

If usage data isn’t in the stream, the handler fetches it from the generation endpoint:

// From openrouter.ts:163-168
if (!didOutputUsage) {
  const apiStreamUsage = await handler.getApiStreamUsage()
  if (apiStreamUsage) {
    console.log("Cost from generation endpoint:", apiStreamUsage.totalCost)
  }
}

Error Handling

OpenRouter returns errors in two ways:

Direct Error Response

// From openrouter.ts:78-85
if ("error" in chunk) {
  const error = chunk.error
  console.error(`OpenRouter Error ${error.code}: ${error.message}`)
  if (error.metadata) {
    console.error("Metadata:", error.metadata)
  }
}

Mid-Stream Error

// From openrouter.ts:91-105
if (choice?.finish_reason === "error") {
  const error = choice.error
  throw new Error(`OpenRouter Mid-Stream Error: ${error}`)
}

Error Types

type OpenRouterErrorResponse = {
  error: {
    message: string
    code: number
    metadata?: {
      provider_name?: string
      raw?: unknown
      reasons?: string[] // For moderation errors
      flagged_input?: string
    }
  }
}

Streaming Response

Text Chunks

{
  type: "text",
  text: string
}

Reasoning Chunks

{
  type: "reasoning",
  reasoning: string,
  details?: any // Reasoning details to preserve
}

Tool Calls

{
  type: "tool_calls",
  tool_call: {
    function: {
      name: string,
      arguments: string
    }
  }
}

Usage Data

{
  type: "usage",
  inputTokens: number,
  outputTokens: number,
  cacheReadTokens: number,
  cacheWriteTokens: 0,
  totalCost: number // USD
}

Model Information

OpenRouter caches model info:

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet"
})

const { id, info } = handler.getModel()

console.log("Model ID:", id)
console.log("Context window:", info.contextWindow)
console.log("Max tokens:", info.maxTokens)
console.log("Input price:", info.inputPrice)
console.log("Output price:", info.outputPrice)

Model info is cached in StateManager to avoid repeated API calls.

Skipping Reasoning for Specific Models

Some models (like Grok 4) output placeholder reasoning:

// From openrouter.ts:125
if (delta.reasoning && !shouldSkipReasoningForModel(modelId)) {
  yield {
    type: "reasoning",
    reasoning: delta.reasoning
  }
}

Advanced Usage

Multiple Provider Fallback

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet",
  openRouterProviderSorting: "anthropic,openai,google"
  // Try Anthropic -> OpenAI -> Google
})

Custom Model Info

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "custom/model",
  openRouterModelInfo: {
    maxTokens: 16384,
    contextWindow: 200000,
    supportsPromptCache: true,
    inputPrice: 3.0,
    outputPrice: 15.0
  }
})

Retry Configuration

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet",
  onRetryAttempt: (error, attempt, maxRetries) => {
    console.log(`Retry ${attempt}/${maxRetries}:`, error.message)
  }
})

Generation Details API

Access detailed generation info:

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet"
})

// Stream a message
for await (const chunk of handler.createMessage(...)) {
  // ...
}

// Get detailed usage after streaming
const usage = await handler.getApiStreamUsage()
if (usage) {
  console.log("Native prompt tokens:", usage.inputTokens)
  console.log("Native completion tokens:", usage.outputTokens)
  console.log("Cached tokens:", usage.cacheReadTokens)
  console.log("Total cost:", usage.totalCost)
}

From openrouter.ts:171-193, the generation endpoint:

Returns native token counts
Includes cache statistics
Provides exact cost calculations
Has built-in retry logic (4 attempts)

Implementation Reference

Source: ~/workspace/source/src/core/api/providers/openrouter.ts Key features:

Unified access to 100+ models
Automatic provider fallback
Cost tracking with generation endpoint
Reasoning details preservation
Error handling for stream and response
Model info caching

Common Patterns

Cost Monitoring

let totalCost = 0

for await (const chunk of handler.createMessage(...)) {
  if (chunk.type === "usage" && chunk.totalCost) {
    totalCost += chunk.totalCost
  }
}

console.log(`Total cost: $${totalCost.toFixed(4)}`)

Provider Preference

// Always use official Anthropic
const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: "anthropic/claude-4.5-sonnet",
  openRouterProviderSorting: "anthropic"
})

Multi-Model Strategy

const models = {
  planning: "openai/o3-mini",
  coding: "anthropic/claude-4.5-sonnet",
  fast: "google/gemini-3.0-flash-thinking"
}

const handler = new OpenRouterHandler({
  openRouterApiKey: process.env.OPENROUTER_API_KEY,
  openRouterModelId: models.coding
})

Next Steps

Anthropic Provider

Direct Anthropic integration

OpenAI Provider

Direct OpenAI integration

Provider Overview

View all providers

Custom Provider

Build your own

​Configuration

​Basic Setup

​Provider Routing

​Reasoning Models

​DeepSeek Reasoner

​Gemini with Thinking

​Anthropic Extended Thinking

​Reasoning Details Preservation

​Tool Calling

​Cost Tracking

​Generation Endpoint Fallback

​Error Handling

​Direct Error Response

​Mid-Stream Error

​Error Types

​Streaming Response

​Text Chunks

​Reasoning Chunks

​Tool Calls

​Usage Data

​Model Information

​Skipping Reasoning for Specific Models

​Advanced Usage

​Multiple Provider Fallback

​Custom Model Info

​Retry Configuration

​Generation Details API

​Implementation Reference

​Common Patterns

​Cost Monitoring

​Provider Preference

​Multi-Model Strategy

​Next Steps

Anthropic Provider

OpenAI Provider

Provider Overview

Custom Provider

Configuration

Basic Setup

Provider Routing

Reasoning Models

DeepSeek Reasoner

Gemini with Thinking

Anthropic Extended Thinking

Reasoning Details Preservation

Tool Calling

Cost Tracking

Generation Endpoint Fallback

Error Handling

Direct Error Response

Mid-Stream Error

Error Types

Streaming Response

Text Chunks

Reasoning Chunks

Tool Calls

Usage Data

Model Information

Skipping Reasoning for Specific Models

Advanced Usage

Multiple Provider Fallback

Custom Model Info

Retry Configuration

Generation Details API

Implementation Reference

Common Patterns

Cost Monitoring

Provider Preference

Multi-Model Strategy

Next Steps