SkillShield

Security scanner for AI agent skills. It looks for known prompt-injection, data-exfiltration and malicious-payload patterns in a skill before you install it.

SkillShield is a first line of defence, not a complete one: see Limitations and the roadmap.

Contributors welcome. Pick an issue and comment /assign to claim it: good first issues · help wanted · detection gaps · roadmap

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The problem

An agent skill is a file of instructions or code that an AI agent loads and follows. A malicious skill can tell the agent to ignore its instructions, read your files and send them to someone else.

• On 1 February 2026, Koi Security reported that it audited all 2,857 skills on ClawHub, the skill marketplace for OpenClaw. It found 341 malicious skills. 335 of them came from one campaign, which Koi named ClawHavoc. [1]
• Snyk’s ToxicSkills study scanned 3,984 skills from ClawHub and skills.sh. 534 skills (13.4%) had at least one critical issue. 1,467 skills had at least one security issue. Snyk confirmed 76 malicious payloads. [2]
• The OWASP Agentic Skills Top 10 lists Malicious Skills as AST01 and Supply Chain Compromise as AST02. [3]

skillshield checks skill files for these patterns with 13 rules. It runs locally and needs no network access.

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Install

pip install skillshield

This installs the skillshield command and the skillshield Python package.

Formerly skillguard

This project was called skillguard until version 1.1.0. The PyPI package was always skillshield, so pip install skillshield is unchanged. Until 2.0.0: