Skillguard

skillguard

**Security scanner for AI agent skills. Detects prompt injection, data exfiltration, and malicious payloads before you install. Zero dependencies.**

[](tests/) [](https://pypi.org/project/skillguard/) [](pyproject.toml) [](pyproject.toml) [](LICENSE) [](https://www.linkedin.com/in/linda-oraegbunam/)

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The problem

In January 2026, the **ClawHavoc campaign** dropped 341 malicious skills into the Claude skill marketplace in 3 days. Snyk's **ToxicSkills audit** found that **13.4% of 3,984 skills** contain critical security issues — prompt injection payloads, data exfiltration code, and rug-pull remote execution. The OWASP Agentic Skills Top 10 lists skill supply-chain attacks as the #1 risk for AI agents.

There is no open-source scanner for this. Until now.

pip install skillguard
skillguard scan SKILL.md

CRITICAL  my_skill.md
  Risk score:  80/100
  Findings:    3

  [SG-011] Lethal Trifecta (Supply Chain Attack Pattern)
  Severity: CRITICAL
  Description:
    Prompt injection + network access + file system access detected
    together. This combination is the hallmark of ClawHavoc-style
    supply chain attack skills.
  Remediation:
    Immediately reject and report this skill.
  Lines: [4, 12, 19]

  [SG-001] Prompt Injection
  Severity: CRITICAL
  Description:
    The skill contains text that attempts to override the agent's
    system prompt. Primary technique used in ClawHavoc campaign.

  [SG-002] Data Exfiltration
  Severity: CRITICAL