How to Install the Auto-Scatter Hook for Claude Code

Leave a comment on any sinc-LLM article and I will send you the GitHub link. The repo is github.com/mdalexandre/sinc-llm. Clone it or download the ZIP.

git clone https://github.com/mdalexandre/sinc-llm
cd sinc-llm

The scatter server is a FastAPI app. Install the requirements. Then start the server. It runs on port 8461.

pip install -r requirements.txt

# Start the scatter server (keep this running)
uvicorn sinc_llm.scatter_server:app --port 8461 --host 127.0.0.1

# Or run as background process on Windows:
# start /b py -X utf8 -m uvicorn sinc_llm.scatter_server:app --port 8461

Check that it is running. Open http://127.0.0.1:8461/health in your browser. It should return {"status": "ok"}.

The scatter server calls Claude Haiku. Set your API key as an environment variable:

# Windows
set ANTHROPIC_API_KEY=sk-ant-your-key-here

# Or add to your .env file in the sinc-llm directory
ANTHROPIC_API_KEY=sk-ant-your-key-here

Find your Claude Code settings.json. On Mac or Linux it is usually at ~/.claude/settings.json. On Windows it is at %APPDATA%\Claude\settings.json. Add the hook entry:

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": ".*",
        "hooks": [{
          "type": "command",
          "command": "py -X utf8 /path/to/sinc-llm/sinc_llm/scatter_hook.py"
        }]
      }
    ]
  }
}

Replace /path/to/sinc-llm with the real path where you installed sinc-llm. On Windows, use forward slashes or double backslashes.

Restart Claude Code. Send any prompt. You should see the scatter JSON before the response. The hook echoes the output so you can confirm it is running.

# Run the test script to confirm hook is active
py -X utf8 sinc_llm/test_scatter.py

# Expected output:
# [PASS] Server health check
# [PASS] Scatter API response
# [PASS] sinc JSON validation (6 bands present)
# [PASS] Pass-through detection (sinc JSON input)
# [PASS] Edge case: @agent routing
# All tests passed.