@justack/claude-hook

Human-in-the-loop tool approvals for Claude Code. Routes dangerous tool calls to a human reviewer via Justack for approval before execution.

How it works

Registers as a Claude Code PreToolUse hook. When Claude tries to use a tool (Bash, Write, Edit, MCP tools), the hook:

1. Evaluates the tool call against configurable rules
2. Auto-approves safe commands (e.g. ls, git status)
3. Sends dangerous/unknown commands to your Justack inbox for approval
4. Blocks until you approve or deny — with optional feedback and argument modification

Installation

npm install -g @justack/claude-hook

Or run directly with npx (no install needed):

npx @justack/claude-hook init

Quick start

1. Get a Justack API key

Sign up at justack.dev and create an API key from the dashboard.

2. Initialize the hook

cd your-project
npx @justack/claude-hook init

The wizard will:

• Prompt for your API key (jstk_...) or read JUSTACK_API_KEY from env
• Prompt for the reviewer's email address
• Validate credentials against the Justack API
• Create .justack/config.json with default rules
• Add .justack/ to .gitignore
• Register the hook in .claude/settings.json

3. Use Claude Code as normal

The hook runs automatically. When Claude triggers a dangerous action, you'll get a notification in your Justack inbox with the full tool call details, diffs, and an approve/deny prompt.

Default rules

| Tool | Mode | Behavior | |------|------|----------| | Bash | pattern | Auto-approves safe commands, flags dangerous ones, asks for unknown | | Write | all | All file writes require approval | | Edit | all | All file edits require approval | | mcp__* | all | All MCP tool calls require approval |

Safe patterns (auto-approved): ls, cat, git status, git diff, git log, pnpm install, tsc, eslint, etc.

Dangerous patterns (require approval): rm, git push, sudo, curl -X POST, npm publish, node, python, etc.

Configuration

The config lives at .justack/config.json in your project root:

{
  "apiKey": "jstk_...",
  "recipientEmail": "[email protected]",
  "rules": {
    "Bash": {
      "mode": "pattern",
      "dangerous": ["rm ", "git push", "..."],
      "safe": ["ls", "git status", "..."]
    },
    "Write": { "mode": "all" },
    "Edit": { "mode": "all" },
    "mcp__*": { "mode": "all" }
  }
}

Rule modes

• all — Every call to this tool requires approval
• none — Auto-approve everything (skip this tool)
• pattern — Match against dangerous and safe substring lists. Unknown commands require approval.

Tool names support glob patterns (e.g. mcp__* matches all MCP tools).

Environment variables

| Variable | Description | |----------|-------------| | JUSTACK_API_KEY | API key (used by init if set, avoids interactive prompt) |

License

MIT