dcg

name	dcg
description	Destructive Command Guard - High-performance Rust hook for Claude Code that blocks dangerous commands before execution. SIMD-accelerated, modular pack system, whitelist-first architecture. Essential safety layer for agent workflows.

DCG — Destructive Command Guard

A high-performance Claude Code hook that intercepts and blocks destructive commands before they execute. Written in Rust with SIMD-accelerated filtering for sub-millisecond latency.

Why This Exists

AI coding agents are powerful but fallible. They can accidentally run destructive commands:

• "Let me clean up the build artifacts" → rm -rf ./src (typo)
• "I'll reset to the last commit" → git reset --hard (destroys uncommitted changes)
• "Let me fix the merge conflict" → git checkout -- . (discards all modifications)
• "I'll clean up untracked files" → git clean -fd (permanently deletes untracked files)

DCG intercepts dangerous commands before execution and blocks them with a clear explanation, giving you a chance to stash your changes first.

Critical Design Principles

1. Whitelist-First Architecture

Safe patterns are checked before destructive patterns. This ensures explicitly safe commands are never accidentally blocked:

git checkout -b feature    →  Matches SAFE "checkout-new-branch"  →  ALLOW
git checkout -- file.txt   →  No safe match, matches DESTRUCTIVE  →  DENY

2. Fail-Safe Defaults (Default-Allow)

Unrecognized commands are allowed by default. This ensures:

• The hook never breaks legitimate workflows
• Only known dangerous patterns are blocked
• New git commands work until explicitly categorized