@bifrostlabs/claude-shield

Security and protection hooks for Claude Code. Blocks destructive commands, protects sensitive files, prevents force pushes to protected branches, and maintains a full audit trail — all through Claude Code's hook system.

Features

• Destructive command blocking — catches rm -rf, DROP TABLE, git reset --hard, chmod 777, and more
• Sensitive file protection — blocks writes to .env, *.pem, *.key, credentials files, SSH keys
• Force push prevention — blocks git push --force to protected branches (main/master by default)
• Full audit trail — SQLite-backed logging of every blocked action and tool execution
• Custom rules — add your own blocked commands, protected files, and protected branches via config
• Zero config start — ships with sensible defaults, customize via JSON config

Quick Start

npm install @bifrostlabs/claude-shield

Add hooks to your Claude Code settings.json:

{
  "hooks": {
    "PreToolUse": [{ "command": "claude-shield-pre-tool" }],
    "PostToolUse": [{ "command": "claude-shield-post-tool" }]
  }
}

Configuration

Config lives at ~/.claude-shield/config.json (auto-created on first run):

{
  "enabled": true,
  "block_destructive_commands": true,
  "block_protected_files": true,
  "block_force_push": true,
  "audit_logging": true,
  "audit_retention_days": 30,
  "blocked_commands": [],
  "protected_files": [],
  "protected_branches": ["main", "master"]
}

Custom Rules

Add your own patterns:

{
  "blocked_commands": ["docker system prune", "kubectl delete namespace"],
  "protected_files": ["*.tfstate", "production.yml"],
  "protected_branches": ["main", "master", "release/*"]
}

What Gets Blocked

Destructive Commands

rm -rf, DROP TABLE, DROP DATABASE, TRUNCATE TABLE, git reset --hard, git clean -f, git checkout ., git restore ., chmod 777, mkfs.*, writes to /dev/sd*, git commit --no-verify

Protected Files

.env, .env.*, credentials.*, *.pem, *.key, *.p12, *.pfx, id_rsa, id_ed25519, *.keystore, secrets.*, service-account*.json, firebase-adminsdk*.json, .npmrc, .pypirc

Force Push

git push --force and git push -f to protected branches (main/master by default)

API

import {
  checkBlockedCommand,
  checkProtectedFile,
  loadConfig,
  recentBlocked,
  recentAudit,
} from "@bifrostlabs/claude-shield";

const config = loadConfig();

// Check if a command would be blocked
const result = checkBlockedCommand("rm -rf /", config);
// { blocked: true, ruleType: "destructive_command", ... }

// Check if a file write would be blocked
const fileResult = checkProtectedFile(".env.production", config);
// { blocked: true, ruleType: "protected_file", ... }

How It Works

1. PreToolUse hook intercepts Bash commands and file writes before execution — blocks if they match destructive patterns or target protected files
2. PostToolUse hook logs all tool executions to the audit database for compliance and review

License

MIT