Night Market Skill — ported from claude-night-market/phantom. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

Computer Control Skill

Use Claude's Computer Use API to see and control desktop environments through screenshots and mouse/keyboard actions.

When To Use

• Automating GUI-based workflows that lack CLI alternatives
• Testing web applications through visual interaction
• Filling forms, navigating menus, or interacting with desktop apps
• Building automation pipelines that need visual verification

When NOT To Use

• Tasks achievable through CLI or API (no GUI needed)
• Browser automation better served by Playwright or CDP

Architecture

The computer use system has three layers:

1. Display Toolkit (phantom.display) - executes OS-level actions via xdotool/scrot on the real or virtual display
2. Agent Loop (phantom.loop) - manages the conversation cycle between Claude API and the display toolkit
3. CLI (phantom.cli) - command-line interface for running tasks or checking environment readiness

User Task
    |
    v
Agent Loop  <---->  Claude API (beta)
    |                   |
    v                   v
Display Toolkit    tool_use responses
    |              (click, type, screenshot)
    v
OS Commands (xdotool, scrot)
    |
    v
Display (X11 / Xvfb / WSLg)

Quick Start

Check environment

cd plugins/phantom
uv run python -m phantom.cli --check

Run a task

export ANTHROPIC_API_KEY="sk-ant-..."
uv run python -m phantom.cli "Open Firefox and search for Claude AI"

Use in Python

from phantom.display import DisplayConfig, DisplayToolkit
from phantom.loop import LoopConfig, run_loop

result = run_loop(
    task="Take a screenshot of the desktop",
    api_key="sk-ant-...",
    loop_config=LoopConfig(
        model="claude-sonnet-4-6",
        max_iterations=10,
    ),
    display_config=DisplayConfig(width=1920, height=1080),
)

print(f"Done in {result.iterations} iterations")
print(result.final_text)

API Versions

The resolve_tool_version() function handles this mapping automatically based on the model name.

Available Actions

All versions:

• screenshot - capture display
• left_click - click at [x, y]
• type - type text string
• key - press key combo (e.g., ctrl+s)
• mouse_move - move cursor

Enhanced (20250124+):

• scroll - scroll with direction and amount
• left_click_drag - drag between coordinates
• right_click, middle_click, double_click, triple_click
• hold_key - hold key for duration
• wait - pause between actions

Latest (20251124):

• zoom - inspect screen region at full resolution

Safety

Computer use carries risks. Follow these guidelines:

1. Use a sandbox: Run in Docker or a VM, not your main OS
2. Limit access: Do not provide login credentials unless necessary, and never for banking or sensitive services
3. Set iteration caps: Always use max_iterations to prevent runaway API costs
4. Human approval: For actions with real-world consequences, add confirmation callbacks via on_action
5. Close sensitive apps: Claude sees the full screen via screenshots; close anything private before starting

Environment Requirements

Linux (native or WSL2 with WSLg):

sudo apt install xdotool scrot xclip

Headless (Docker/CI):

# Install Xvfb for virtual display
sudo apt install xvfb xdotool scrot xclip
Xvfb :1 -screen 0 1920x1080x24 &
export DISPLAY=:1

Prompting Tips

1. Be specific about each step of the task
2. Add "After each step, take a screenshot and verify" to catch mistakes early
3. Use keyboard shortcuts when UI elements are hard to click
4. Provide example screenshots for repeatable workflows
5. Set a system prompt with domain-specific instructions