sandboxxer-linux-troubleshoot

Native Linux/WSL2 Troubleshooting Assistant

Overview

Diagnoses and resolves common issues with Claude Code CLI running natively on Linux/WSL2 (without Docker containers). This skill focuses on bubblewrap sandboxing, environment configuration, WSL2-specific issues, and authentication problems.

When to Use This Skill

Use this skill when:

• Bubblewrap sandbox failures or permission errors
• Claude Code CLI not found or installation failures
• PATH environment issues
• WSL2-specific problems (networking, file permissions, distro issues)
• Git or GitHub CLI authentication problems
• Claude API authentication failures
• System package installation errors
• Sudo permission issues or credential timeout problems

Do NOT use this skill when:

• Setting up a new native Linux installation (use /sandboxxer:yolo-linux-maxxing instead)
• Working with Docker-based sandboxes (use /sandboxxer:troubleshoot instead)
• Auditing security (use /sandboxxer:audit instead)

Usage

Via slash command:

/sandboxxer:linux-troubleshoot

Via natural language:

• "Claude Code not found after installation"
• "Bubblewrap permission denied"
• "WSL2 networking issues"
• "Can't authenticate Claude"
• "PATH not working on Linux"

Examples

Example: Claude Code Not Found

User: "I installed Claude Code but the command isn't found"

Assistant: "I'll help troubleshoot the PATH configuration issue."

The skill will:

1. Check if Claude Code binary exists
2. Verify PATH configuration in ~/.bashrc
3. Test shell environment loading
4. Provide commands to fix PATH
5. Verify the fix works

Example: Bubblewrap Permission Error

User: "Getting permission denied when running bubblewrap"

Assistant: "Let's diagnose the bubblewrap sandbox issue."

The skill will:

1. Verify bubblewrap installation
2. Test basic bubblewrap functionality
3. Check kernel user namespace support
4. Identify permission issues
5. Provide specific fix based on error

Troubleshooting Workflow

1. Identify the Problem Category

Ask user to describe the issue, then categorize:

• Bubblewrap Issues: Sandbox failures, permission errors, kernel limitations
• Claude CLI Issues: Installation failures, command not found, API errors
• WSL2-Specific Issues: Networking, file permissions, systemd problems
• PATH/Environment Issues: Tools not found after installation
• Git/GitHub CLI Issues: Authentication, configuration problems
• Authentication Issues: Claude auth login failures, API key problems
• Sudo/Permission Issues: Credential timeouts, sudoers access, privilege errors

2. Gather Diagnostic Information

Run appropriate diagnostic commands:

Bubblewrap Issues:

# Check bubblewrap installation
bwrap --version

# Test basic functionality
bwrap --ro-bind / / --dev /dev --proc /proc --tmpfs /tmp -- echo "test"

# Check user namespace support
cat /proc/sys/kernel/unprivileged_userns_clone

# Check setuid bit (some distros)
ls -la $(which bwrap)

Claude CLI Issues:

# Check if claude is installed
which claude

# Check version
claude --version

# Check PATH
echo $PATH | tr ':' '\n' | grep -i claude

# Check binary location
ls -la ~/.local/bin/claude /usr/local/bin/claude 2>/dev/null

# Check shell configuration
cat ~/.bashrc | grep -E "(PATH|claude)"

WSL2-Specific Issues:

# Verify WSL2 environment
cat /proc/version | grep -i microsoft

# Check WSL version (from Windows)
wsl.exe --status 2>/dev/null

# Check networking
ping -c 1 google.com

# Check DNS resolution
nslookup google.com

# Check file permissions
ls -la /etc/resolv.conf

PATH/Environment Issues:

# Check current PATH
echo $PATH

# Check shell configuration files
cat ~/.bashrc
cat ~/.bash_profile 2>/dev/null
cat ~/.profile 2>/dev/null

# Test shell reload
source ~/.bashrc && echo "Reload successful"

# Check which shell
echo $SHELL

Git/GitHub CLI Issues:

# Check installations
git --version
gh --version

# Check Git config
git config --global --list

# Check GitHub authentication
gh auth status

# Check Git credentials
git config --global credential.helper

Authentication Issues:

# Check Claude authentication status
claude auth whoami

# Check API key location
ls -la ~/.claude/

# Test API connectivity
curl -I https://api.anthropic.com/

3. Apply Systematic Fixes

Based on the diagnostic results, apply fixes:

Bubblewrap Permission Denied

Issue: bwrap: setting up uid map: Permission denied

Fix 1 - Enable user namespaces (Debian/Ubuntu):

# Check current setting
cat /proc/sys/kernel/unprivileged_userns_clone

# Enable user namespaces (requires sudo)
sudo sysctl -w kernel.unprivileged_userns_clone=1

# Make persistent across reboots
echo "kernel.unprivileged_userns_clone=1" | sudo tee -a /etc/sysctl.conf

# Verify
bwrap --ro-bind / / --dev /dev --proc /proc --tmpfs /tmp -- echo "Success!"

Fix 2 - WSL2-specific (if Fix 1 doesn't work):

# Add to /etc/wsl.conf
sudo tee /etc/wsl.conf > /dev/null <<EOF
[boot]
systemd=true

[user]
default=$(whoami)
EOF

# Restart WSL from Windows PowerShell
wsl.exe --shutdown

Fix 3 - Reinstall bubblewrap with proper permissions:

sudo apt-get remove bubblewrap -y
sudo apt-get update
sudo apt-get install bubblewrap -y

Claude Code Not Found

Issue: bash: claude: command not found

Fix 1 - Reload shell configuration:

# Reload ~/.bashrc
source ~/.bashrc

# Verify
which claude
claude --version

Fix 2 - Fix PATH in ~/.bashrc:

# Check if Claude install location is in PATH
echo $PATH | grep -E "(\.local/bin|usr/local/bin)"

# Add to PATH if missing
echo 'export PATH="$HOME/.local/bin:/usr/local/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc

# Verify
which claude

Fix 3 - Reinstall Claude Code CLI:

# Download and run installer
curl -fsSL https://claude.ai/install.sh | bash

# Reload shell
source ~/.bashrc

# Verify
claude --version

Fix 4 - Check binary exists:

# Find Claude binary
find ~ -name "claude" -type f 2>/dev/null

# If found in ~/.local/bin but not working
chmod +x ~/.local/bin/claude
export PATH="$HOME/.local/bin:$PATH"

WSL2 Networking Issues

Issue: Can't reach external sites or DNS resolution fails

Fix 1 - Reset DNS configuration:

# Remove existing resolv.conf
sudo rm /etc/resolv.conf

# Create new one with Google DNS
sudo tee /etc/resolv.conf > /dev/null <<EOF
nameserver 8.8.8.8
nameserver 8.8.4.4
EOF

# Prevent WSL from overwriting
sudo chattr +i /etc/resolv.conf

# Test
ping -c 1 google.com

Fix 2 - Restart WSL networking (from Windows PowerShell):

wsl --shutdown
# Wait 10 seconds, then restart WSL
wsl

Fix 3 - Disable WSL DNS generation:

# Edit /etc/wsl.conf
sudo tee /etc/wsl.conf > /dev/null <<EOF
[network]
generateResolvConf = false
EOF

# Then apply Fix 1 (DNS reset) and restart WSL

Git/GitHub CLI Authentication

Issue: Git push fails or GitHub CLI not authenticated

Fix 1 - Configure Git:

# Set Git credentials
git config --global user.name "Your Name"
git config --global user.email "[email protected]"

# Set credential helper
git config --global credential.helper store

# Verify
git config --global --list

Fix 2 - Authenticate GitHub CLI:

# Login to GitHub
gh auth login

# Follow prompts:
# - Choose "GitHub.com"
# - Choose "HTTPS"
# - Authenticate with browser

# Verify
gh auth status

Fix 3 - Generate SSH key for Git:

# Generate new SSH key
ssh-keygen -t ed25519 -C "[email protected]"

# Start ssh-agent
eval "$(ssh-agent -s)"

# Add key
ssh-add ~/.ssh/id_ed25519

# Display public key (add to GitHub)
cat ~/.ssh/id_ed25519.pub

Claude Authentication Failures

Issue: claude auth login fails or API errors

Fix 1 - Re-authenticate:

# Logout first
claude auth logout

# Login again
claude auth login

# Follow browser prompts

# Verify
claude auth whoami

Fix 2 - Clear authentication cache:

# Remove existing credentials
rm -rf ~/.claude/

# Re-authenticate
claude auth login

# Verify
claude auth whoami

Fix 3 - Check network connectivity to Anthropic API:

# Test API endpoint
curl -I https://api.anthropic.com/

# Should return HTTP 200 or similar

# If fails, check firewall/proxy settings

System Package Installation Failures

Issue: apt-get install fails or packages not found

Fix 1 - Update package lists:

# Update apt cache
sudo apt-get update

# Upgrade existing packages
sudo apt-get upgrade -y

# Retry installation
sudo apt-get install <package-name> -y

Fix 2 - Fix broken packages:

# Fix broken dependencies
sudo apt-get install -f

# Reconfigure packages
sudo dpkg --configure -a

# Clean apt cache
sudo apt-get clean
sudo apt-get autoclean

# Update again
sudo apt-get update

Fix 3 - Check disk space:

# Check available space
df -h

# If low, clean up
sudo apt-get autoremove -y
sudo apt-get clean

# Check again
df -h

Sudo Credential Timeout During Installation

Issue: Installation steps hang or fail waiting for sudo password mid-way through setup

Cause: The yolo-linux-maxxing installation validates sudo credentials at the start, but credentials expire after ~15 minutes (default timestamp_timeout). If you take time between steps, subsequent sudo commands will prompt for password again.

Prevention - Refresh credentials before each step:

# Run before each step that uses sudo
sudo -v

Fix 1 - Enter password when prompted: If a command hangs, it may be waiting for your sudo password. Type your password and press Enter.

Fix 2 - Refresh sudo credentials manually:

# Refresh sudo credentials (will prompt if expired)
sudo -v

# Then retry the failed command

Fix 3 - Extend sudo timeout temporarily:

# Increase timeout to 60 minutes for this session
sudo visudo
# Add/modify: Defaults timestamp_timeout=60

User Not in Sudoers Group

Issue: sudo: user not in sudoers file

Cause: Your user account doesn't have sudo privileges

Fix 1 - Add user to sudo group (requires root access):

# If you have root password
su -
usermod -aG sudo your_username
exit
# Log out and back in

Fix 2 - WSL2: Reset to default user:

# From Windows PowerShell (as Admin)
wsl -d Ubuntu -u root
usermod -aG sudo your_username
exit

Partial GitHub CLI Installation (Cleanup)

Issue: GitHub CLI installation failed partway through, leaving orphaned files

Cause: Sudo timeout or network failure during the multi-step gh installation

Fix - Clean up and retry:

# Remove partial installation artifacts
sudo rm -f /etc/apt/keyrings/githubcli-archive-keyring.gpg
sudo rm -f /etc/apt/sources.list.d/github-cli.list

# Update apt to clear stale references
sudo apt update

# Retry GitHub CLI installation
# (copy the full command from /sandboxxer:yolo-linux-maxxing Step 3)

Seccomp Filter Not Detected

Issue: /sandbox shows "seccomp filter: not installed" after running npm install

Cause: On Debian/Ubuntu, npm global packages require sudo to install to /usr/lib/node_modules. Without sudo, the package installs to user directories but the seccomp filter binary is not placed in the system location where Claude Code expects it.

Fix 1 - Install with sudo:

# Install sandbox-runtime with sudo
sudo npm install -g @anthropic-ai/sandbox-runtime

# Verify installation
npm list -g @anthropic-ai/sandbox-runtime

# Test in Claude Code
# Run /sandbox and check for "seccomp filter: installed"

Fix 2 - If Node.js not installed first:

# Install Node.js 20 (LTS)
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt-get install -y nodejs

# Verify Node.js installation
node --version
npm --version

# Then install sandbox-runtime with sudo
sudo npm install -g @anthropic-ai/sandbox-runtime

# Verify installation
npm list -g @anthropic-ai/sandbox-runtime

Fix 3 - Reinstall if already installed without sudo:

# Remove existing installation (if installed without sudo)
npm uninstall -g @anthropic-ai/sandbox-runtime

# Reinstall with sudo
sudo npm install -g @anthropic-ai/sandbox-runtime

# Verify installation
npm list -g @anthropic-ai/sandbox-runtime

4. Verify the Fix

After applying fixes, verify:

• Tools are accessible via command line
• Authentication works
• Bubblewrap can run sandboxed commands
• Networking is functional
• Original error is resolved

Provide verification commands:

# Verify Claude Code
claude --version
claude auth whoami

# Verify bubblewrap
bwrap --version
bwrap --ro-bind / / --dev /dev --proc /proc --tmpfs /tmp -- echo "Sandbox working!"

# Verify Git/GitHub
git --version
gh auth status

# Verify networking (WSL2)
ping -c 1 google.com
curl -I https://api.anthropic.com/

# Verify PATH
echo $PATH
which claude
which git
which gh

Common Issues Quick Reference

"sudo: a password is required"

Cause: Sudo credentials expired during multi-step installation Fix: Run sudo -v to refresh credentials, then retry the command

"sudo: user not in sudoers file"

Cause: User account lacks sudo privileges Fix: Add user to sudo group via su - or WSL root access

"claude: command not found"

Cause: PATH not configured or shell not reloaded Fix: Run source ~/.bashrc and verify PATH includes Claude install location

"bwrap: Permission denied"

Cause: User namespaces disabled in kernel Fix: Enable with sudo sysctl -w kernel.unprivileged_userns_clone=1

"Network unreachable" in WSL2

Cause: WSL DNS configuration issues Fix: Reset /etc/resolv.conf with Google DNS (8.8.8.8)

"gh auth status" shows not authenticated

Cause: GitHub CLI not logged in Fix: Run gh auth login and authenticate via browser

"claude auth login" fails

Cause: Network issues or expired credentials Fix: Check network connectivity, clear ~/.claude/ and re-authenticate

Package installation hangs

Cause: Stale apt cache or network issues Fix: Run sudo apt-get update and retry

Bubblewrap works but Claude doesn't

Cause: Claude CLI installation incomplete Fix: Reinstall with curl -fsSL https://claude.ai/install.sh | bash

Changes to ~/.bashrc not taking effect

Cause: Shell not reloaded or wrong shell configuration file Fix: Run source ~/.bashrc or restart terminal

"seccomp filter: not installed"

Cause: npm package not installed globally with sudo, or Node.js not installed Fix: Run sudo npm install -g @anthropic-ai/sandbox-runtime (requires Node.js 20+ installed first)

Reset Everything (Last Resort)

If nothing works, provide nuclear option:

# === COMPLETE REINSTALL ===

# 1. Remove all components
sudo apt-get remove bubblewrap socat git gh -y
rm -rf ~/.claude/
rm -rf ~/.local/bin/claude

# 2. Clean apt cache
sudo apt-get autoremove -y
sudo apt-get clean

# 3. Update system
sudo apt-get update && sudo apt-get upgrade -y

# 4. Reinstall everything (run /sandboxxer:yolo-linux-maxxing)
# Or manually:
sudo apt-get install bubblewrap socat git curl wget unzip -y

# Install GitHub CLI
(type -p wget >/dev/null || (sudo apt update && sudo apt install wget -y)) \
    && sudo mkdir -p -m 755 /etc/apt/keyrings \
    && out=$(mktemp) && wget -nv -O$out https://cli.github.com/packages/githubcli-archive-keyring.gpg \
    && cat $out | sudo tee /etc/apt/keyrings/githubcli-archive-keyring.gpg > /dev/null \
    && sudo chmod go+r /etc/apt/keyrings/githubcli-archive-keyring.gpg \
    && echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | sudo tee /etc/apt/sources.list.d/github-cli.list > /dev/null \
    && sudo apt update \
    && sudo apt install gh -y

# Install Claude Code CLI
curl -fsSL https://claude.ai/install.sh | bash

# 5. Configure environment
echo 'export PATH="$HOME/.local/bin:/usr/local/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc

# 6. Verify everything
bwrap --version
socat -V
git --version
gh version
claude --version

# 7. Authenticate
claude auth login
gh auth login

Warning: This removes all configurations. Back up important data first.

WSL2-Specific Troubleshooting

Identifying WSL2 Environment

# Check if running in WSL2
cat /proc/version | grep -i microsoft

# Check WSL version (from Windows PowerShell)
wsl.exe --status

# Check WSL distro name
cat /etc/os-release | grep PRETTY_NAME

Common WSL2 Issues

Issue 1: Systemd not available

# Enable systemd in /etc/wsl.conf
sudo tee /etc/wsl.conf > /dev/null <<EOF
[boot]
systemd=true
EOF

# Restart WSL (from Windows PowerShell)
wsl.exe --shutdown

Issue 2: File permissions incorrect

# Fix file permissions for project
chmod -R u+rwX,go+rX-w .

# Fix WSL2 metadata (if using NTFS)
# Add to /etc/wsl.conf
sudo tee -a /etc/wsl.conf > /dev/null <<EOF
[automount]
options = "metadata"
EOF

Issue 3: Slow file access

# Move project from /mnt/c to ~ for better performance
cp -r /mnt/c/Users/YourName/project ~/project
cd ~/project

Key Principles

• Systematic approach - Run diagnostic commands before guessing
• One fix at a time - Test after each change
• Verify assumptions - Check actual state, not expected state
• Document what worked - Help user understand the fix
• Explain root cause - Teach, don't just fix
• Environment-specific - Recognize WSL2 vs native Linux differences

Reference Documentation

For detailed setup instructions, see:

• /sandboxxer:yolo-linux-maxxing - Complete installation guide
• Claude Code Documentation - Official documentation
• WSL2 documentation: https://docs.microsoft.com/en-us/windows/wsl/

Footer

---