Dep Guard Skill

Automated dependency security enforcement. The PreToolUse hook intercepts all package install commands and enforces:

1. Registry connectivity — hard-blocks if offline (can't verify = can't install)
2. Latest versions — resolves and upgrades outdated version requests
3. Vulnerability scanning — checks OSV.dev for known CVEs before install

How It Works

The dep-guard.py hook runs on every Bash command. If it detects an install command (npm install, pip install, composer require, etc.), it:

1. Pings the registry to confirm it's reachable
2. Extracts package names and requested versions
3. Queries the registry for latest versions
4. Queries OSV.dev for vulnerabilities against the target version
5. Makes a decision:

Condition	Action
Registry offline	BLOCK — hard stop until online
Scan failed	BLOCK — can't verify safety
Critical/High vuln	BLOCK — must find alternative
Medium vuln	WARN — allow with warning
Low/no vulns	ALLOW
Outdated version requested	BLOCK — provide corrected command
No version specified	ALLOW — will get latest automatically
Lockfile install (npm ci, etc.)	SKIP — no new packages

Supported Ecosystems

Ecosystem	Install Commands	Registry	Vuln Source
npm	npm install/i/add	npmjs.org	OSV.dev (npm)
yarn	yarn add	npmjs.org	OSV.dev (npm)
pnpm	pnpm add/install	npmjs.org	OSV.dev (npm)
bun	bun add/install	npmjs.org	OSV.dev (npm)
pip	pip install, uv add	pypi.org	OSV.dev (PyPI)
composer	composer require	packagist.org	OSV.dev (Packagist)

Commands

• /dep-check [package] — Check a specific package before installing
• /dep-audit [--fix] — Audit all installed dependencies

Logs

Debug logs are written to /tmp/dep-guard.log for troubleshooting.

Critical Rule: No Wrapper Scripts

You MUST always run package install commands directly via the Bash tool. Never create a script in any language that internally invokes a package manager to circumvent the hook.

Prohibited patterns include:

• Writing Python, Node, shell, or any other script files that run install commands internally via process spawning
• Using inline interpreter calls (e.g. python3 -c or node -e) that wrap install commands
• Using remote execution (docker, ssh) to install packages outside the hook's reach

All of these bypass the dep-guard security hook. If the hook blocks an install, that block is intentional. Do not work around it. Instead, inform the user why the install was blocked and suggest an alternative package or version.

Bypassing (Emergency Only)

If the hook blocks something incorrectly, the user can disable the plugin temporarily in .claude/settings.json. The hook should never be bypassed in normal operation.