Claude Max API proxy

claude-max-api-proxy is a community npm package (not an OpenClaw plugin) that exposes a Claude Max/Pro subscription as an OpenAI-compatible API endpoint, so you can point any OpenAI-compatible tool at your subscription instead of an Anthropic API key.

Technical compatibility only, not an officially sanctioned path. Anthropic has blocked some subscription usage outside Claude Code in the past; verify Anthropic’s current billing rules before relying on this.

Anthropic’s Claude Code docs describe claude -p as Agent SDK/programmatic usage. As of Anthropic’s June 15, 2026 support update, Claude Agent SDK, claude -p, and third-party app usage draw from the signed-in subscription’s usage limits (the previously announced separate Agent SDK credit plan is paused). See Anthropic’s Agent SDK plan article, the Pro/Max and Team/Enterprise plan articles, and Anthropic provider for OpenClaw’s own Claude CLI billing notes.

Why use this

Approach	Cost route	Best for
Anthropic API key	Pay per token through Claude Console	Production apps, shared automation, volume
Claude subscription proxy	Claude Code / claude -p plan and credit rules	Personal experiments with compatible tools

This proxy lets a Claude Max or Pro subscription work with OpenAI-compatible tools. It is not an unlimited flat-rate path — it inherits Claude Code’s usage limits. API keys remain the clearer billing path for production use.

How it works

Your App -> claude-max-api-proxy -> Claude Code CLI / claude -p -> Anthropic
     (OpenAI format)                (converts format)              (uses your login)

The proxy spawns the Claude Code CLI as a subprocess per request, converts OpenAI-format chat requests to CLI prompts, and streams (or returns) the response back in OpenAI format.

Getting started

1. Install the proxy

   Requires Node.js 20+ and an authenticated Claude Code CLI.

   npm install -g claude-max-api-proxy
   
   # Verify Claude CLI is authenticated
   claude --version
   claude auth login   # if not already authenticated
   
2. Start the server

   claude-max-api
   # Server runs at http://localhost:3456
   
3. Test the proxy

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

   Point OpenClaw at the proxy as a custom OpenAI-compatible endpoint:

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

The model ids below are the proxy’s own catalog, not OpenClaw’s Anthropic model refs. Each id maps to a Claude Code CLI model alias (opus, sonnet, haiku), so the underlying model shifts whenever Anthropic updates that alias in the CLI. Check the proxy’s current README before relying on a specific mapping.

Model ID	CLI alias	Current mapping
claude-opus-4	opus	Claude Opus 4.5
claude-sonnet-4	sonnet	Claude Sonnet 4
claude-haiku-4	haiku	Claude Haiku 4

Advanced configuration

Proxy-style OpenAI-compatible notes

This uses OpenClaw’s generic custom /v1 OpenAI-compatible route, the same path as any other self-hosted OpenAI-compatible backend:

• Native OpenAI-only request shaping does not apply.
• /fast and service_tier only apply to direct api.anthropic.com traffic; proxy routes leave service_tier untouched (see Anthropic provider fast mode).
• No Responses store, prompt-cache hints, or OpenAI reasoning-compat payload shaping.
• OpenClaw’s OpenAI/Codex attribution headers (originator, version, User-Agent) are only sent on native api.openai.com OAuth traffic, not on custom OPENAI_BASE_URL targets like this proxy.

Auto-start on macOS with LaunchAgent

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

Notes

• Inherits Claude Code’s claude -p billing, usage-credit, and rate-limit behavior.
• Binds to 127.0.0.1 only; does not send data to any third-party server beyond the CLI’s own call to Anthropic.
• Streaming responses are supported.
• Auth failures are not checked at startup and only surface once a chat request actually runs; if the CLI is unauthenticated, expect the first request to fail rather than the server to refuse to start.

For native Anthropic integration with Claude CLI or API keys, see Anthropic provider. For OpenAI/Codex subscriptions, see OpenAI provider.

Related

Anthropic provider

Native OpenClaw integration with Claude CLI or API keys.

OpenAI provider

For OpenAI/Codex subscriptions.

Model selection

Overview of all providers, model refs, and failover behavior.

Configuration

Full config reference.