Build AI Code Guardrails: Claude Hooks in 5 Steps

Originally published at chudi.dev I ran a secret scanner on every project for months before I realized Claude Code was writing .env files with real credentials baked in. Not because it was malicious. Just because the context had a key, and it needed a value. The fix took five minutes once I knew hooks existed. Claude Code hooks let you run any shell command automatically when tool events fire. Before a file gets written, after a bash command runs, when Claude finishes a task. You get full context about what's happening via stdin, and for PreToolUse hooks, you can block the operation entirely. This is the guide I wish I had when I started. What Are Claude Code Hooks and Why Do You Need Them? Claude Code is an autonomous agent. It reads files, writes code, runs commands, and makes decisions faster than you can review each one. That autonomy is the point. But it creates a gap: how do you enforce standards without reviewing every action manually? Hooks close that gap. They're your enforcem