signal-path

A small coding agent with a browser chat UI. Built for the coding-agent-ui eval (cursor-composer-2).

• Harness: Cursor
• Model: OpenAI Chat Completions (default gpt-4o) — override with CC2_MODEL
• Stack: Python 3.10+ · FastAPI · WebSockets · vanilla JS frontend (no build step)

The agent exposes:

• bash — run a shell command in the working directory.
• read_file — read a file (optional line range).
• write_file — overwrite / create a file.
• edit_file — exact string replacement in a file.
• list_dir — list a directory.

Assistant text and tool use stream to the browser so you can follow the run in real time.

UI (HTML)

• Markup / assets: frontend/index.html (loads frontend/styles.css and frontend/app.js).
• Rendered in the browser (after python -m cc2): http://127.0.0.1:8765/ (same as http://localhost:8765/).

Run it

Requires Python 3.10+ and an OpenAI API key (OPENAI_API_KEY).

cd backend
python3 -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt

export OPENAI_API_KEY=sk-...
# Optional: directory the agent’s tools use (defaults to cwd at launch).
export CC2_WORKDIR="$PWD/../scratch"
mkdir -p "$CC2_WORKDIR"

python -m cc2

Open http://localhost:8765 in your browser and start chatting.

Configuration

Warnings

The agent has real shell and filesystem access on your machine. There is no sandbox. Run it only where you accept that risk.

Layout

signal-path/
├── README.md
├── backend/
│   ├── requirements.txt
│   └── cc2/
│       ├── __init__.py
│       ├── __main__.py
│       ├── server.py
│       ├── agent.py
│       └── tools.py
└── frontend/
    ├── index.html
    ├── styles.css
    └── app.js