agent-b2b

Go back-to-back with your AI agent — a beat system that reacts to Claude Code's state.

https://github.com/user-attachments/assets/6fdd0bff-ac24-4d52-b333-5fd2bb17f9d1

Example

• YOURTURN (waiting for prompt): kick + bass + hihat
• OPPONENT (AI processing): melody layer kicks in

Setup

npx agent-b2b

The browser opens automatically at http://localhost:43819.

To use a different port:

npx agent-b2b --port 12345

Add the following hooks to your Claude Code config (.claude/settings.json):

{
  "hooks": {
    "UserPromptSubmit": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "curl -s -X POST http://localhost:43819/thinking",
            "timeout": 5
          }
        ]
      }
    ],
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "curl -s -X POST http://localhost:43819/idle",
            "timeout": 5
          }
        ]
      }
    ]
  }
}

You can optionally add PreToolUse and PostToolUse hooks to detect tool approval prompts. This switches the state to YOURTURN while waiting for approval and back to OPPONENT once approved. Add or remove these based on your preference:

{
  "PreToolUse": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "curl -s -X POST http://localhost:43819/idle",
          "timeout": 5
        }
      ]
    }
  ],
  "PostToolUse": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "curl -s -X POST http://localhost:43819/thinking",
          "timeout": 5
        }
      ]
    }
  ]
}

All communication stays on localhost after installation. No data is sent to the internet.

Alternative: clone and run

git clone https://github.com/hogashi/agent-b2b.git
cd agent-b2b
npm install
npm start

Usage

1. Power on — Click the power button to start audio. This is required each time the page loads.
2. Use Claude Code — While Claude is thinking, the melody layer kicks in. When it's your turn, only kick, bass, and hihat play. You can customize which tracks play in each state using the checkboxes.
3. (Optional) Adjust — Change the volume of each track, tweak the BPM, or edit the beat pattern in the sequencer.
4. (Optional) Share — Export your settings as JSON to back up or share with friends. You can also reset everything to defaults.

Troubleshooting

No sound Click the power button to start audio. This is required every time the page loads due to the browser's Web Audio API policy.

PLUGGED indicator is red The server is not running. Run npm start and check that the port is not in use by another process.

State does not change (stuck on YOURTURN/OPPONENT) Make sure the Claude Code hooks are configured in .claude/settings.json. See the Setup section above.

Port

The default port is 43819 (0xAB2B for agent-b2b).

Playground

Try the beat system without installing: https://hogashi.github.io/agent-b2b/

Note: Claude Code integration (WebSocket) is not available in the playground. Use npx agent-b2b for the full experience.