SkillsGuard

---

---

⚡ Install & Use in 60 seconds

Option A — Free cloud API (no install)

# Scan any SKILL.md with a single curl — no account, no key
curl -s --data-binary @SKILL.md \
  https://skillsguard.apiskillsguard.workers.dev/scan | jq .

Option B — Build from source and link globally

Note: SkillsGuard is not currently published on the npm registry. Install by cloning and building from source.

# 1. Clone, install, build, and link
git clone https://github.com/Teycir/SkillsGuard.git
cd SkillsGuard
npm install
npm run build
npm link

# 2. Scan any skill directory or file
skillsguard /path/to/skill

That's it. SkillsGuard prints color-coded findings to the terminal (or --json for CI).
Exit code 0 = clean · 1 = findings · 2 = usage error.

Want Claude to call the scanner automatically inside your agent workflow? See Local Workflow → Path B for the full skill + MCP setup.

---

How It Works

flowchart TD
    A([Folder, file, or Git diff target]) --> B[Load config\nskillsguard.config.json]
    B --> C[File discovery\nFilter JS, PY, PS1, Docker, Ruby...]
    C --> D{For each file}
    D --> E[Raw text scan\nApply 100+ rules]
    D --> F[decode.ts\nExtract encoded blobs]
    F --> G[Recursive decode\nbase64, hex, URL]
    G --> H[Scan decoded content]
    E & H --> I{Findings?}
    I -->|no| J([✅ Clean — exit 0])
    I -->|yes| K[Deduplicate findings]
    K --> L[Compute Risk Score\n0 - 100]
    L --> M{Output mode}
    M -->|CLI| N[ANSI colored report]
    M -->|--json| O[JSON output]
    M -->|--sarif| P[SARIF output]
    M -->|MCP| Q[MCP response]
    N & O & P & Q --> R{Risk > max-risk?}
    R -->|yes| S([❌ Exit 1])
    R -->|no| J

    style A fill:#0d1117,stroke:#00ff88,color:#c3f5dc
    style J fill:#0d1117,stroke:#00ff88,color:#00ff88
    style S fill:#0d1117,stroke:#ff4444,color:#ff8888
    style G fill:#0d1117,stroke:#f0a500,color:#f0c060
    style K fill:#0d1117,stroke:#00ff88,color:#c3f5dc

Key insight: SkillsGuard decodes obfuscated payloads before scanning, so a base64-wrapped reverse shell can't slip through. Every finding is deduplicated — each rule fires at most once per file per line.

---

Table of Contents

• How SkillsGuard Compares
• Why SkillsGuard
• Features
• Threat Coverage
• Quick Start
• Local Workflow
  • Kiro CLI — Complete Example
  • Real-World Example — Self-Auditing Installed Skills
• CLI Usage
• Git Diff Mode
• Configuration File
• Risk Scoring & Gating
• SARIF Output
• Model-Specific Rules
• Rule Explorer & Tuning
• Watch Mode
• Baseline Workflow
• Pre-commit Hook
• MCP Server
• HTTP Server
• Cloud API (Free)
• Live Demo
• Library API
• Rules Reference
• Obfuscation Detection
• Test Fixtures
• Project Structure
• Limitations
• Contributing
• License
• Attribution
• Related Projects
• Support Development

---

How SkillsGuard Compares

The agent-skill security space filled up fast in 2026 — NVIDIA, Cisco, Snyk, and Mondoo have all shipped scanners for this exact problem. Worth knowing the field before you pick a tool, including this one.

At a glance

Tool	Backing	Requires account/token	Requires LLM call for core scan	Detection approach	Notable extra
SkillsGuard	Independent, MIT	No	No	Static regex, decode-first (recursive base64/hex/URL/Unicode unwrap)	Pre-commit hook + git-diff mode; free curl API
NVIDIA SkillSpector	NVIDIA, Apache 2.0	No	No (optional, for semantic stage)	Static + optional LLM semantic pass	Live OSV.dev dependency-CVE lookup
Cisco AI Defense Skill Scanner	Cisco	No	No (optional, for semantic stage)	Multi-engine: static + behavioral dataflow + LLM semantic + cloud	GitHub Actions workflow built-in
Snyk Agent Scan (formerly mcp-scan)	Snyk, commercial	Yes — SNYK_TOKEN required	Yes — deterministic rules + LLM judges combined	Auto-discovery across Claude/Cursor/Windsurf/Gemini CLI + MCP servers	Powers Vercel's at-install skill scanning
SkillScan	Independent	No	Only for predict mode (optional)	YAML rule engine + optional LLM behavioral dry-run + optional Docker sandbox	Temporal/delayed-activation detection via LLM role-play
Mondoo Skill Check	Mondoo, commercial	No (free tier, non-commercial)	Unclear from public docs	Static, maps to OWASP LLM Top 10	Hosted dashboard + REST API

The throughline that matters most: SkillsGuard is the only tool in this table that needs nothing beyond Node ≥18.3 to run a full scan — no account, no API token, no LLM endpoint, no network call. Every other actively-maintained competitor either requires signing up for a service (Snyk) or recommends configuring an LLM provider to get full coverage (NVIDIA, Cisco, SkillScan). That makes SkillsGuard the simplest choice for a CI gate or pre-commit hook that has to run the same way, offline, every time — and the LLM-augmented tools the better choice when you want semantic/intent-level review and don't mind the extra dependency.