AI coding tools write fast. They also write the same security vulnerabilities repeatedly, because they learned from code that had those mistakes in it. VibeGuard is a security linter built specifically around the exact patterns GitHub Copilot, Cursor, ChatGPT, Claude and Gemini produce: → SQL injection via f-strings → Hardcoded API keys and passwords → JWT without algorithm verification → Command injection via shell=True → MD5 for password hashing → DEBUG=True shipped to production