Package Manager Guard (PMG)

Why PMG?

AI coding agents install packages you didn't choose. Claude Code, Cursor, Copilot, Windsurf all run npm install and pip install autonomously, and you have no idea what they just put on your machine.

PMG ensures every package is checked for malware before it executes, whether you picked it or an AI agent did.

1. Analyze packages for malware before they are installed.
2. Sandbox the installation process to prevent system modification.
3. Audit every package installation event.

Install PMG once, and every npm install, pip install, and poetry add is protected automatically.

Featured in tl;dr sec and used by engineering teams worldwide to secure their software supply chain.

How PMG is Different

Most security tools scan after installation and report vulnerabilities. By then, malicious code has already executed on your machine.

PMG intercepts package managers before code executes, blocking malicious packages at install time, not flagging them after the damage is done. Detection is powered by SafeDep's malicious package analysis engine. For defense in depth, PMG sandboxes the installation process using OS-native isolation, so even zero-day malware that evades detection cannot modify your system.

Quick Start

Get protected in seconds.

1. Install

MacOS / Linux (Homebrew)

brew install safedep/tap/pmg

NPM

npm install -g @safedep/pmg

See Installation for additional methods.

2. Setup

Configure your shell to use PMG automatically.

pmg setup install
# Restart your terminal to apply changes

3. Use

Use your package managers as usual — or let your AI coding agent use them. PMG works silently in the background.

npm install express
# or
pip install requests

Verify PMG is working by installing a test package. This is a harmless package flagged as malicious in the SafeDep database, specifically meant for testing:

npm i safedep-test-pkg@0.1.3

Expected output

✗ Malicious package blocked

  - safedep-test-pkg@0.1.3
    Reference: https://app.safedep.io/community/malysis/01KF5JYDND9XR94WNEJ2G74KY2

✗ PMG: 1 packages analyzed, 1 blocked

Features

Feature	Description
AI Agent Safety Net	Protects against malicious packages installed by AI coding agents (Claude Code, Cursor, Copilot, Windsurf).
Malicious Package Protection	Real-time protection against malicious packages using SafeDep.
Sandboxing	Enforces least privilege using OS native sandboxing to contain installation scripts.
Dependency Analysis	Deep scans of direct and transitive dependencies before they hit your disk.
Event Logging	Keeps a verifiable audit trail of all installed packages.
Zero Config	Works out of the box with sensible security defaults.
Cross-Shell	Seamlessly integrates with Zsh, Bash, Fish, and more.

Supported Package Managers

PMG supports the tools you already use:

Ecosystem	Tools	Status	Command Example
Node.js	npm	Yes	npm install <pkg>
	pnpm	Yes	pnpm add <pkg>
	yarn	Yes	yarn add <pkg>
	bun	Yes	bun add <pkg>
	npx	Yes	npx <pkg>
	pnpx	Yes	pnpx <pkg>
Python	pip	Yes	pip install <pkg>
	poetry	Yes	poetry add <pkg>
	uv	Yes	uv add <pkg>

Installation

Homebrew (MacOS/Linux)

brew tap safedep/tap
brew install safedep/tap/pmg

NPM (Cross-Platform)

npm install -g @safedep/pmg

Go (Build from Source)

# Ensure $(go env GOPATH)/bin is in your $PATH
go install github.com/safedep/pmg@latest

Binary Download

Download the latest binary for your platform from the Releases Page.

Trust and Security

Security is our first class requirement. PMG builds are reproducible and signed.

• Attestations: GitHub and npm attestations are used to guarantee artifact integrity.
• Verification: Users can cryptographically prove the binary matches the source code.
• See Trusting PMG for verification steps.

User Guide

• Trusted Packages Configuration
• Proxy Mode Architecture
• Sandboxing Details

Support

If PMG saved you from a bad package, star this repo — it helps others find it.

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines on how to build and test PMG locally.

Telemetry

PMG collects anonymous usage data to improve project stability and reliability. To disable: export PMG_DISABLE_TELEMETRY=true.