🛡️ SaveClaudeNode

Protect Your Claude Code Sessions from Accidental Termination

Multi-layered defense against killing all Node.js processes

English • 繁體中文 • Installation • Features

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😫 The Problem

Ever accidentally killed ALL Node.js processes with this command?

taskkill /F /IM node.exe  # Windows
pkill node                 # Linux/Mac

💥 What actually happens:

• ❌ Claude Code terminates → Your entire session is lost
• ❌ Development servers die → All your running apps crash
• ❌ Background tasks killed → Build processes, watchers, everything
• ❌ Work interrupted → Have to restart everything from scratch

You just wanted to kill ONE stubborn server on port 3000. Instead, you nuked your entire Node.js ecosystem.

✨ The Solution

SaveClaudeNode provides two-layer protection:

🚫 Layer 1: Prevention PreToolUse Hook Blocks dangerous commands before they execute inside Claude Code Effectiveness: ~95%

📊 Layer 2: Monitoring Guardian Daemon Monitors all Node.js processes and logs termination events Effectiveness: 100% logging

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🎯 Features

🛡️ Smart Detection Auto-identifies Claude Code processes Command-line argument pattern matching Real-time process monitoring (500ms scan interval) Zero false positives	⚡ Lightweight & Fast Only 287KB executable < 0.1% CPU usage Rust-powered performance Native Windows integration
📝 Complete Audit Trail Logs all protected processes Records termination events Timestamp + PID tracking Full command history	🔧 Easy Setup One-click hook installer No manual configuration Works out-of-the-box Auto-start on boot options

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🚀 Installation

⚡ Quick Install (Recommended)

Install PreToolUse Hook only (blocks 95% of accidental kills):

PowerShell: git clone https://github.com/Jeffrey0117/saveclaudenode.git cd saveclaudenode .\install-hook.ps1

Command Prompt: git clone https://github.com/Jeffrey0117/saveclaudenode.git cd saveclaudenode install-hook.bat

Restart Claude Code → ✅ Protected!

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🔨 Advanced Install (Hook + Guardian Daemon)

For full protection with monitoring:

1. Install Rust:

winget install Rustlang.Rustup

2. Build Guardian:

git clone https://github.com/Jeffrey0117/saveclaudenode.git
cd saveclaudenode
cargo build --release

3. Install Hook:

.\install-hook.ps1

4. Run Guardian:

# Visible window
.\start-guard.bat

# Background (recommended)
.\start-guard-silent.vbs

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📖 Usage

Testing the Hook

After installation, try this command in Claude Code:

taskkill /F /IM node.exe

Expected Output:

⛔ 禁止無差別殺 node.exe！這會把 Claude Code 也殺掉！

請使用 /kill <端口號> 來精確殺掉特定端口的進程。

✅ Hook is working!

Guardian Daemon Output

════════════════════════════════════════════════
   SaveClaudeNode - Node.js Process Guardian
════════════════════════════════════════════════

[2026-01-28 07:30:15] 🚀 SaveClaudeNode guardian started
[2026-01-28 07:30:15] 📁 Log file: saveclaudenode.log
[2026-01-28 07:30:15] ⏱️  Scan interval: 500ms

守護程式已啟動！
- Monitoring all node.exe and electron.exe processes
- Auto-detecting Claude Code processes
- Log file: saveclaudenode.log

[2026-01-28 07:30:16] 🛡️  Protected Claude Code process: PID 12345
[2026-01-28 07:35:22] ⚠️  ALERT: Protected process PID 12345 was TERMINATED!

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🛠️ How It Works

Architecture

graph TB
    A[User Types Command] --> B{Inside Claude Code?}
    B -->|Yes| C[PreToolUse Hook]
    C --> D{Dangerous Command?}
    D -->|Yes| E[❌ BLOCKED]
    D -->|No| F[✅ Execute]

    B -->|No| G[External Command]
    G --> H[Guardian Daemon]
    H --> I{Claude Code Killed?}
    I -->|Yes| J[⚠️ Log Alert]
    I -->|No| K[Continue Monitoring]

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Protection Layers

Layer	Tool	What It Blocks	Effectiveness	Limitation
1	PreToolUse Hook	taskkill /IM node.exe pkill node Stop-Process -Name node	~95%	Only works inside Claude Code
2	Guardian Daemon	N/A - Monitoring only	100% logging	Cannot prevent termination

Blocked Command Patterns

The hook detects and blocks these patterns:

# Windows
taskkill /F /IM node.exe
taskkill //F //IM node.exe
taskkill /IM electron.exe
wmic process where name="node.exe" delete

# PowerShell
Stop-Process -Name node
Get-Process node | Stop-Process

# Unix-style (if running in WSL/Git Bash)
pkill node
killall node
kill -9 $(pidof node)

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📁 Project Structure

saveclaudenode/
├── 🦀 src/
│   └── main.rs                  # Rust guardian daemon source
├── 🪝 hooks/
│   └── block-node-kill.js       # Claude Code PreToolUse hook
├── 📦 target/release/
│   └── saveclaudenode.exe       # Compiled binary (287KB)
├── 🔧 install-hook.ps1          # PowerShell hook installer
├── 🔧 install-hook.bat          # Batch hook installer
├── ▶️ start-guard.bat           # Start daemon (visible)
├── 🔇 start-guard-silent.vbs    # Start daemon (background)
├── 📖 README.md                 # This file
├── 📖 INSTALL.md                # Detailed installation guide
└── ⚖️ LICENSE                   # MIT License

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⚙️ Configuration

Auto-start on Windows Boot

Option 1: Startup Folder (Easiest)

1. Press Win + R
2. Type shell:startup → Enter
3. Copy start-guard-silent.vbs to the opened folder
4. ✅ Guardian will start automatically on boot

Option 2: Task Scheduler (More Control)

$action = New-ScheduledTaskAction -Execute "C:\path\to\saveclaudenode.exe"
$trigger = New-ScheduledTaskTrigger -AtLogOn
Register-ScheduledTask -TaskName "SaveClaudeNode" -Action $action -Trigger $trigger -RunLevel Highest

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🔍 Technical Details

Guardian Daemon

Spec	Value
Language	Rust 🦀
Dependencies	sysinfo, chrono, windows-rs
Binary Size	287KB
CPU Usage	< 0.1%
Memory	~2MB
Scan Interval	500ms
Detection Method	Process diff + CLI pattern matching

PreToolUse Hook

Spec	Value
Language	JavaScript
Hook Type	PreToolUse (pre-execution)
Detection	Regex + keyword analysis
False Positives	Near zero
Performance Impact	< 1ms per command

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🚧 Known Limitations

Guardian Daemon

⚠️ Monitoring Only, Not Prevention

The guardian daemon can:

• ✅ Detect when Claude Code is killed
• ✅ Log all termination events with timestamps
• ✅ Track which processes were terminated

But it cannot:

• ❌ Prevent termination (would require kernel driver)
• ❌ Restart Claude Code automatically
• ❌ Recover lost session data

Why? Windows security model prevents user-space apps from blocking process termination. Only kernel-mode drivers can do this.

Best Practice

✅ Use both layers together:

• Hook blocks 95% of accidental kills inside Claude Code
• Guardian provides audit trail for external terminations
• Combined protection covers most scenarios

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🗺️ Roadmap

Short-term

• Windows Service mode (run as system service)
• Desktop notifications on Claude Code termination
• Whitelist mechanism (allow specific PIDs)
• Process recovery (experimental auto-restart)

Long-term

• Kernel driver version (true prevention)
• Linux/macOS support
• Cloud logging & analytics
• Multi-user session support

Want a feature? Open an issue!

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🤝 Contributing

Contributions are welcome! This project was born from frustration.

Ways to Contribute

• 🐛 Report bugs - Open an issue
• 💡 Suggest features - Share your ideas
• 🔧 Submit PRs - Fix bugs or add features
• ⭐ Star the repo - Help others discover it
• 📢 Share - Tell your fellow Claude Code users

Development Setup

# Clone the repo
git clone https://github.com/Jeffrey0117/saveclaudenode.git
cd saveclaudenode

# Install Rust
winget install Rustlang.Rustup

# Build
cargo build --release

# Test
.\target\release\saveclaudenode.exe

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📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

TL;DR: Free to use, modify, and distribute. Just keep the license notice.

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🙏 Acknowledgments

Created by developers who got tired of accidentally killing their Claude Code sessions. 😅

Special thanks to:

• Everyone who's ever typed taskkill /IM node.exe in frustration
• The Rust community for amazing system programming tools
• Claude Code team for making such an awesome tool worth protecting

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📞 Support

• 🐛 Bug reports: GitHub Issues
• 💬 Questions: GitHub Discussions
• ⭐ Feature requests: GitHub Issues