Browser Zombie Cleaner

Detect and clean up zombie browser processes left by OpenClaw's browser tool. When the OpenClaw Gateway restarts, Playwright-launched browser processes get orphaned and accumulate memory. This skill identifies them safely and optionally terminates them. Use when: memory is high, browser processes are piling up, or as part of periodic health checks.

Detect and clean up orphaned browser processes left behind when OpenClaw Gateway restarts.

The Problem

OpenClaw's browser tool uses Playwright to launch Chrome/Chromium/Firefox. When the Gateway restarts (update, crash, manual restart), these browser child processes become orphans — their parent PID changes to 1 (init/systemd). They keep running, consuming memory, and accumulate over days.

Safety Design

This tool is safe by default:

1. Detect-only mode is the default — no processes are killed without --kill
2. Triple verification before killing: OpenClaw user-data-dir pattern + orphaned PPID + minimum age
3. Only current user's processes — never touches other users
4. Only OpenClaw browsers — identified by ~/.openclaw/browser/ in the command line
5. Graceful shutdown — SIGTERM first, SIGKILL only after grace period
6. Audit log — every action is logged to /tmp/openclaw/zombie-browser-cleanup.log
7. No root required — runs as regular user

Usage

Detect only (safe, default)

bash

bash <skill_dir>/scripts/cleanup-zombie-browsers.sh

Output example:

text

Found 8 OpenClaw browser processes, 5 are zombies (1200MB total)
  ZOMBIE: PID=66301 PPID=1 age=3d 2h mem=388MB
  ZOMBIE: PID=152356 PPID=1 age=2d 4h mem=168MB
  ...
Run with --kill to terminate these zombie processes

Detect and clean

bash

bash <skill_dir>/scripts/cleanup-zombie-browsers.sh --kill

Options

Option	Default	Description
--kill	off	Actually terminate zombie processes
--min-age N	3600 (1h)	Only target processes older than N seconds
--grace N	10	Seconds between SIGTERM and SIGKILL
--json	off	Output as JSON (for programmatic use)
--log PATH	/tmp/openclaw/zombie-browser-cleanup.log	Log file location
--pattern STR	.openclaw/browser/	Pattern to identify OpenClaw browsers

Integration with Health Checks

Add to your health check script or heartbeat:

bash

# Detect and report (no kill)
bash /path/to/cleanup-zombie-browsers.sh

# Auto-clean with safety margin (processes must be >2 hours old)
bash /path/to/cleanup-zombie-browsers.sh --kill --min-age 7200

How It Identifies Zombies

A process is classified as a zombie browser if ALL of these are true:

1. Browser process — executable name matches chrome/chromium/brave/msedge/firefox
2. OpenClaw origin — command line contains .openclaw/browser/ (the user-data-dir used by OpenClaw)
3. Orphaned — PPID is 1 (init) or systemd, meaning the parent Gateway process is gone
4. Old enough — process age exceeds --min-age threshold (prevents killing browsers that are actively initializing)

If ANY condition is not met, the process is skipped.

Platform Support

Platform	Status	Notes
Linux	Full	Uses /proc filesystem for precise detection
macOS	Full	Uses ps with etime parsing
Windows	Not yet	Planned (PowerShell-based)

Supported Browsers

All Playwright-supported browsers with OpenClaw user-data-dir:

• Google Chrome / Chromium
• Brave Browser
• Microsoft Edge
• Firefox

Exit Codes

Code	Meaning
0	No zombies found, or zombies cleaned (--kill mode)
1	Zombies detected but not killed (detect mode)