Claude Code

SkillSpector: Stop a Malware Claude Skill at the Door, Before You Install It

A free, open-source scanner from NVIDIA. Point it at a skill folder or GitHub link and it checks every file for 71 known attack patterns, then gives a 0-100 risk score and a plain answer: safe, caution or do not install

Alex ChenAlex Chen@nocodealex · 50,000+ follow on Instagram
2min read
1prompts to copy
5numbered steps
4sections

Claude skills run with a lot of trust: a skill is a folder of instructions and scripts that Claude follows and runs. NVIDIA's SkillSpector reads that folder before you install it and tells you whether anything inside looks dangerous. In NVIDIA's research set of 31,132 skills, 26.1% had a vulnerability and 5.2% showed likely malicious intent.

What it checks (from the README)

  • 71 patterns in 17 categories, including prompt injection, hidden instructions, data exfiltration, stealing environment variables (API keys), privilege escalation, supply-chain risks and MCP tool poisoning.
  • Two stages: a fast static scan, then an optional AI review of what the code and instructions actually do.
  • Scans a folder, a single SKILL.md, a zip file or a GitHub link.
  • Output: a risk score from 0 to 100, a severity (LOW to CRITICAL) and a recommendation: SAFE, CAUTION or DO NOT INSTALL, with the file and line of each finding.

Set it up

  1. You need Python 3.12 or newer and uv (docs.astral.sh/uv).
  2. Install it: uv tool install git+https://github.com/NVIDIA/skillspector.git
  3. Scan a skill before you install it: skillspector scan https://github.com/user/some-skill (or a local folder: skillspector scan ./some-skill/).
  4. For the deeper AI review with your own Claude login and no API key: export SKILLSPECTOR_PROVIDER=claude_cli, then run the same scan. For a quick static-only scan add --no-llm.
  5. Optional, scan from inside Claude Code: uv tool install --force 'skillspector[mcp] @ git+https://github.com/NVIDIA/skillspector.git', then claude mcp add skillspector -- skillspector mcp
PROMPT
PASTE INTO CLAUDE CODE (after adding the MCP server)
Before you install any skill or plugin for me, run scan_skill on it with SkillSpector. Show me the risk score, the recommendation and every HIGH or CRITICAL finding, and don't install anything marked DO NOT INSTALL.

Free, for your email

Get the full setup steps + the copy-paste setup prompt

The rest of this guide (2 more sections) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.

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