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Windows Agent

Runs on the child's PC in the signed-in Windows desktop session. It captures the visible screen, OCRs visible text, sends screenshots to the backend for local classification, and keeps a tray icon visible for pause/status actions.

The installer also registers a GuardianNode Endpoint Broker service and watchdog components for resilience. Desktop capture still happens in the user's interactive session because Windows service session 0 cannot reliably see the child's desktop. In broker mode, the session process sends bounded screenshot payloads over local IPC; the broker owns the device credential, durable queue, pause state, and backend upload transport.

This broker path is experimental until it passes the clean Windows standard-user matrix. Source testing without the broker can set broker_enabled: false in agent.yaml or use --dry-run.

Development setup

cd agent-windows
python3 -m venv .venv
source .venv/bin/activate  # or .venv\Scripts\activate
pip install -e ".[dev]"
python -m src.main --dry-run

--dry-run prints what would be sent without making network calls.

To pair and run from Python source on a Windows child PC:

cd agent-windows
py -3 -m venv .venv
.\.venv\Scripts\python -m pip install --upgrade pip
.\.venv\Scripts\python -m pip install -e ".[windows]"
.\.venv\Scripts\python -m src.main --pair --server http://<server-ip>:8787 --code <pair-code>
.\.venv\Scripts\python -m src.main

Run the tray in a second terminal while testing from source:

.\.venv\Scripts\python -m src.tray_app

Configuration

Local config at C:\ProgramData\GuardianNode\agent.yaml:

backend_url: http://127.0.0.1:8787
age_group: 10_13
ocr_engine: tesseract
ocr_cadence_seconds: 5
ocr_min_confidence: 0.5
phash_threshold: 2
full_screen_capture_enabled: true
monitored_apps:
  - notepad.exe
  - chrome.exe
  - msedge.exe
  - firefox.exe
  - brave.exe

In current installer builds, pairing credentials are intended to live under the broker-owned C:\ProgramData\GuardianNode\Secure\device.json. A legacy C:\ProgramData\GuardianNode\device.json may exist on upgraded alpha systems and is migrated by the broker when possible.

Components

  • main.py — entrypoint, async loop
  • process_watcher.py — psutil-based active process detection
  • window_tracker.py — pywin32 active window detection
  • screenshot_capture.py — mss-based fast capture
  • ocr_engine.py — Tesseract OCR wrapper; PaddleOCR is only a planned optional path
  • redactor.py — best-effort text filtering helpers where used
  • durable_queue.py — encrypted SQLite retry queue for screenshot payloads during outages
  • broker_protocol.py — bounded versioned local IPC protocol
  • broker_client.py — session-process client for the endpoint broker
  • broker_service.py — privileged endpoint broker service entrypoint
  • backend_client.py — HTTP client to backend
  • tray_app.py — pystray-based notification icon and local pause UI
  • watchdog.py — paired watchdog service using Windows Terminal Services APIs for active sessions
  • parent_auth.py — Argon2id credential hashing helpers; recovery codes do not authorize tray actions

Tests

pytest agent-windows/tests/

Some tests require Windows (pywin32); use the dry-run path on Linux.

PyInstaller build

cd agent-windows
py -3 -m venv .venv
.\.venv\Scripts\python -m pip install --upgrade pip
.\.venv\Scripts\python -m pip install -e ".[windows]" pyinstaller
.\.venv\Scripts\pyinstaller --clean --noconfirm guardiannode_agent.spec
.\scripts\verify_windows_bundle.ps1

The shared bundle is written to dist/GuardianNodeAgent/. The release installer expects that complete directory under installer/build/prebuilt/agent; see POWER_USER_INSTALL.md for the full installer build.