What are hooks in Claude Code?

Hooks are shell scripts that run before or after Claude Code performs an action — editing a file, running a Bash command, finishing a tool call. They’re your safety net.

• PreToolUse hooks can block dangerous actions: refuse to rm -rf /, refuse to push to main branch, refuse to write into vendor/, refuse to edit prod credentials. Hook returns non-zero exit, action is cancelled, you stay safe.
• PostToolUse hooks auto-run lint / format / tests after every file edit. phpcs + phpstan + composer validate on every Magento file change — built into the CLI, not bolted on.
• Stop hooks run when Claude finishes a session — great for auto-committing or running test suite.

Configure hooks in .claude/settings.json. They’re the difference between “cool AI demo” and “production-grade workflow.”