skill-guard

name	skill-guard
description	Scan ClawHub skills for security vulnerabilities BEFORE installing. Use when installing new skills from ClawHub to detect prompt injections, malware payloads, hardcoded secrets, and other threats. Wraps clawhub install with mcp-scan pre-flight checks.

skill-guard

The only pre-install security gate for ClawHub skills.

Why skill-guard?

	VirusTotal (ClawHub built-in)	skillscanner (Gen Digital)	skill-guard
When it runs	After publish (server-side)	On-demand lookup	Before install (client-side)
What it checks	Malware signatures	Their database	Actual skill content
Prompt injections	❌	❌	✅
Data exfiltration URLs	❌	❌	✅
Hidden instructions	❌	❌	✅
AI-specific threats	❌	❌	✅
Install blocking	❌	❌	✅

VirusTotal catches known malware binaries — but won't flag <!-- IGNORE PREVIOUS INSTRUCTIONS -->.

skillscanner checks if Gen Digital has reviewed it — but can't scan new or updated skills.

skill-guard uses mcp-scan (Invariant Labs, acquired by Snyk) to analyze what's actually in the skill, catches AI-specific threats, and blocks install if issues are found.

The Problem

Skills can contain:

• 🎭 Prompt injections — hidden "ignore previous instructions" attacks
• 💀 Malware payloads — dangerous commands disguised in natural language
• 🔑 Hardcoded secrets — API keys, tokens in plain text
• 📤 Data exfiltration — URLs that leak your conversations, memory, files
• ⛓️ Toxic flows — instructions that chain into harmful actions

One bad skill = compromised agent. Your agent trusts skills implicitly.

The Solution

# Instead of: clawhub install some-skill
./scripts/safe-install.sh some-skill

skill-guard:

1. Downloads to staging (/tmp/) — never touches your real skills folder
2. Scans with mcp-scan — Invariant/Snyk's security scanner for AI agents
3. Blocks or installs — clean skills get installed, threats get quarantined

What It Catches

Real example — skill-guard flagged this malicious skill:

● [E004]: Prompt injection detected (high risk)
● [E006]: Malicious code pattern detected  
● [W007]: Insecure credential handling
● [W008]: Machine state compromise attempt
● [W011]: Third-party content exposure

VirusTotal: 0/76 engines. mcp-scan caught what antivirus missed.

Usage

# Secure install (recommended)
./scripts/safe-install.sh <skill-slug>

# With version
./scripts/safe-install.sh <skill-slug> --version 1.2.3

# Force overwrite
./scripts/safe-install.sh <skill-slug> --force

Exit Codes

Code	Meaning	Action
0	Clean	Skill installed ✓
1	Error	Check dependencies/network
2	Threats found	Skill quarantined in /tmp/, review before deciding

When Threats Are Found

Skill stays in /tmp/skill-guard-staging/skills/<slug>/ (quarantined). You can:

1. Review — read the scan output, inspect the files
2. Install anyway — mv /tmp/skill-guard-staging/skills/<slug> ~/.openclaw/workspace/skills/
3. Discard — rm -rf /tmp/skill-guard-staging/

Requirements

• clawhub CLI — npm i -g clawhub
• uv — curl -LsSf https://astral.sh/uv/install.sh | sh

Why This Matters

Your agent has access to your files, messages, maybe your whole machine. One malicious skill can:

• Read your secrets and send them elsewhere
• Modify your agent's behavior permanently
• Use your identity to spread to other systems

Trust, but verify. Scan before you install.