Using Claude Max API Proxy with OpenClaw

Prerequisites

• ✓Node.js 20 or later installed on your machine (the proxy requires Node.js 20+).
• ✓Claude Code CLI installed and authenticated with an active Claude Max or Pro subscription.
• ✓An OpenClaw project where you can edit the environment and agent model configuration.
• ✓Ability to run a local service on http://localhost:3456.

Steps

1. 1

   Install the Claude Max API Proxy globally

   Install the proxy as a global npm package so you can run the `claude-max-api` command from anywhere. This binary is what exposes your Claude Max/Pro subscription as an OpenAI-compatible endpoint on localhost.

   bashCopy

   # Requires Node.js 20+ and Claude Code CLI
   npm install -g claude-max-api-proxy
   
   # Verify Claude CLI is authenticated
   claude --version

2. 2

   Start the Claude Max API Proxy server

   Run the proxy so it listens for OpenAI-format requests from your tools and from OpenClaw. By default it binds to `http://localhost:3456`, which you will reference later in your OpenClaw config.

   bashCopy

   claude-max-api
   # Server runs at http://localhost:3456

3. 3

   Smoke-test the proxy with curl

   Before you involve OpenClaw, hit the proxy directly to confirm it is healthy and can talk to Claude via your subscription. Use the health check, model listing, and a simple chat completion to verify everything works end to end.

   bashCopy

   # Health check
   curl http://localhost:3456/health
   
   # List models
   curl http://localhost:3456/v1/models
   
   # Chat completion
   curl http://localhost:3456/v1/chat/completions \
     -H "Content-Type: application/json" \
     -d '{
       "model": "claude-opus-4",
       "messages": [{"role": "user", "content": "Hello!"}]
     }'

4. 4

   Point OpenClaw at the Claude Max API Proxy

   Configure OpenClaw to treat the proxy as a custom OpenAI-compatible backend. You set a dummy `OPENAI_API_KEY`, point `OPENAI_BASE_URL` at the proxy’s `/v1` route, and choose an `openai/claude-opus-4` model so OpenClaw routes traffic through the proxy.

   jsonCopy

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

5. 5

   Run the proxy automatically on macOS (optional)

   If you develop on macOS and want the proxy always available for OpenClaw, set it up as a LaunchAgent. This makes macOS start and keep the proxy alive in the background whenever you log in.

   bashCopy

   cat > ~/Library/LaunchAgents/com.claude-max-api.plist << 'EOF'
   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
   <plist version="1.0">
   <dict>
     <key>Label</key>
     <string>com.claude-max-api</string>
     <key>RunAtLoad</key>
     <true/>
     <key>KeepAlive</key>
     <true/>
     <key>ProgramArguments</key>
     <array>
       <string>/usr/local/bin/node</string>
       <string>/usr/local/lib/node_modules/claude-max-api-proxy/dist/server/standalone.js</string>
     </array>
     <key>EnvironmentVariables</key>
     <dict>
       <key>PATH</key>
       <string>/usr/local/bin:/opt/homebrew/bin:~/.local/bin:/usr/bin:/bin</string>
     </dict>
   </dict>
   </plist>
   EOF
   
   launchctl bootstrap gui/$(id -u) ~/Library/LaunchAgents/com.claude-max-api.plist

Configuration

Troubleshooting

claude-max-api
# Server runs at http://localhost:3456

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

Frequently asked questions