OpenClaw Claude API Integration Tutorial

This tutorial provides a detailed introduction to various methods of configuring the Claude API in OpenClaw to help you get started quickly.

Introduction

OpenClaw is a powerful AI agent framework that supports integrating multiple large language models. Claude is a high-performance AI model developed by Anthropic, showing excellent performance in code generation, reasoning, and analysis.

Preparation

Before getting started, you need to:

Install OpenClaw: npm install -g openclaw
Have the appropriate API access permissions

Method 1: Using Defapi (Recommended)

If you want to save costs, Defapi is recommended!

Defapi is an AI model aggregation platform. All Claude models are priced at half the official rate. Defapi supports the OpenAI-compatible v1/chat/completions interface, making configuration simple and convenient.

Advantages

Half-price: Claude Sonnet 4.5 costs only $1.5/M input, $7.5/M output
Strong compatibility: Perfectly compatible with OpenAI interface formats
Stable and reliable: Fast access within the country

Supported Claude Models

Claude Opus 4.5 / 4.6
Claude Sonnet 4.5
Claude Haiku 4.5

Configuration Steps

Visit Defapi, register an account, and get an API Key
Configure in OpenClaw:

{
  env: {
    OPENAI_API_KEY: "你的Defapi-Key",
    OPENAI_BASE_URL: "https://api.defapi.org/v1",
  },
  agents: {
    defaults: {
      model: { primary: "openai/claude-sonnet-4.5" },
    },
  },
}

Verify the configuration:

# Send a message directly to test (recommended)
openclaw agent --message "Hello"

# Or check model status
openclaw models status

After successful verification, you can converse with Claude in the following ways:

# Send a message directly
openclaw agent --message "你好"

# Or use the terminal UI
openclaw tui

# Or start the Gateway and converse via other channels
openclaw gateway

Now you can enjoy Claude's powerful capabilities at half price!

Method 2: Official Anthropic API

This is the most direct integration method, suitable for users who have an API Key or a Claude subscription.

Method 2.1: API Key Authentication

If you have an Anthropic API Key (pay-as-you-go), configuration is very simple:

openclaw onboard --anthropic-api-key "$ANTHROPIC_API_KEY"

Or add it in the configuration file:

{
  env: { ANTHROPIC_API_KEY: "sk-ant-..." },
  agents: { defaults: { model: { primary: "anthropic/claude-opus-4-6" } } },
}

Verify:

openclaw agent --message "Hello"

Method 2.2: Setup-Token Authentication

If you have a Claude Max/Pro subscription, you can use a setup-token:

# Generate in the Claude Code CLI
claude setup-token

# Configure in OpenClaw
openclaw models auth setup-token --provider anthropic

Tip: Prompt Caching

The Anthropic API supports prompt caching, which can improve performance and reduce costs:

{
  agents: {
    defaults: {
      models: {
        "anthropic/claude-opus-4-6": {
          params: { cacheRetention: "long" },
        },
      },
    },
  },
}

Method 3: OpenRouter

OpenRouter provides a unified API interface and can access various models, including the Claude series.

openclaw onboard --auth-choice apiKey --token-provider openrouter --token "$OPENROUTER_API_KEY"

Configuration:

{
  env: { OPENROUTER_API_KEY: "sk-or-..." },
  agents: {
    defaults: {
      model: { primary: "openrouter/anthropic/claude-sonnet-4-5" },
    },
  },
}

Verify:

openclaw agent --message "Hello"

Method 4: Claude Max API Proxy

If you have a Claude Max subscription but need an OpenAI-formatted interface, you can use the community tool claude-max-api-proxy:

npm install -g claude-max-api-proxy
claude-max-api

Configure OpenClaw:

{
  env: {
    OPENAI_API_KEY: "not-needed",
    OPENAI_BASE_URL: "http://localhost:3456/v1",
  },
  agents: {
    defaults: {
      model: { primary: "openai/claude-opus-4" },
    },
  },
}

Verify:

openclaw agent --message "Hello"

Method 5: Custom Compatible APIs

For other platforms that provide compatible APIs, OpenClaw also supports custom configuration.

v1/chat/completions Format

{
  env: {
    CUSTOM_API_KEY: "sk-...",
  },
  agents: {
    defaults: {
      model: { primary: "custom/claude-model" },
    },
  },
  models: {
    mode: "merge",
    providers: {
      "custom": {
        baseUrl: "https://api.example.com/v1",
        apiKey: "${CUSTOM_API_KEY}",
        api: "openai-completions",
        models: [
          { id: "claude-model", name: "Claude Model", contextWindow: 200000 },
        ],
      },
    },
  },
}

v1/messages Format (Anthropic-compatible)

{
  env: {
    CUSTOM_API_KEY: "sk-...",
  },
  agents: {
    defaults: {
      model: { primary: "custom/claude-opus-4" },
    },
  },
  models: {
    mode: "merge",
    providers: {
      "custom": {
        baseUrl: "https://api.example.com/v1",
        apiKey: "${CUSTOM_API_KEY}",
        api: "anthropic-messages",
        models: [
          { id: "claude-opus-4", name: "Claude Opus 4", contextWindow: 200000 },
        ],
      },
    },
  },
}

Common Models Reference

Model	Configuration Reference
Claude Opus 4.6	`anthropic/claude-opus-4-6`
Claude Sonnet 4.6	`anthropic/claude-sonnet-4-6`
Claude Haiku 4.6	`anthropic/claude-haiku-4-6`

Troubleshooting

Issue: 401 error / Token expired

Rerun claude setup-token and reconfigure

Issue: "No API key found for provider anthropic"

Authentication is isolated per agent; confirm the target agent has authentication configured

Issue: Connection failed

Check network connectivity
Confirm the API Key is correct
Verify the baseUrl configuration is correct