Diagnose Hook Errors

Troubleshoot Claude Code hook errors (PreToolUse, PostToolUse, etc.)

When to Use

• See "PreToolUse: hook error" or "PostToolUse: hook error"
• Hooks silently failing
• Plugin not working as expected

Diagnosis Steps

1. Check Python Alias (Windows)

python3 --version 2>&1

If not found:

cp "C:/Users/Marcus Gollahon/AppData/Local/Programs/Python/Python311/python.exe" \
   "C:/Users/Marcus Gollahon/AppData/Local/Programs/Python/Python311/python3.exe"

2. Find Hooks Using python3

grep -r "python3" ~/.claude/plugins/marketplaces --include="*.json" 2>/dev/null

3. Check Enabled Plugins

grep -A 20 '"enabledPlugins"' ~/.claude/settings.json

4. Test Hook Manually

For a hook command like:

python3 ${CLAUDE_PLUGIN_ROOT}/hooks/security_reminder_hook.py

Test with:

cd ~/.claude/plugins/marketplaces/claude-plugins-official/plugins/security-guidance
echo '{"tool_name":"Write","tool_input":{"file_path":"test.txt"}}' | python3 hooks/security_reminder_hook.py

5. Common Fixes

Quick Disable

To disable a problematic plugin temporarily:

# Edit ~/.claude/settings.json
# Set the plugin to false:
"security-guidance@claude-plugins-official": false

Then restart Claude Code session.