What AgentAudit Found
AgentAudit's 194-package audit identified three dominant vulnerability classes:
| Finding | Severity | Frequency |
|---|---|---|
| Unsanitized shell command injection | Critical/High | Most common |
| Environment variable leakage | High | API keys exposed |
| Overly broad filesystem access | Medium/High | Write access beyond function |
Separately, Snyk reported that 36% of audited skills are vulnerable. Checkmarx identified 11 emerging AI security risks specific to MCP.
MCP-Shield: What It Is
MCP-Shield is an open-source CLI tool on GitHub. It provides:
- CLI-based scanning — runs locally against MCP server configurations
- Open source — code is inspectable and forkable
- GitHub-hosted — community-driven development
Limitations:
- CLI-only — no web interface, no directory, no pre-scanned registry
- MCP-specific — doesn't scan ClawHub skills or SKILL.md definitions
- No scored directory — every scan is manual
- No malicious signature database
- Community project — maintenance depends on contributors
SkillShield: What It Is
SkillShield is a security scanning platform for AI agent skills and MCP servers:
- Pre-scanned directory — 33,746 extensions across six registries
- MCP scanner — free web-based scanning at skillshield.dev/mcp
- CLI scanner — npm install -g skillshield
- Known malicious database — 533 malicious entries blocked
- 99.8% detection rate
The Comparison
| Feature | SkillShield | MCP-Shield |
|---|---|---|
| Pre-scanned directory | ✓ 33,746 extensions | ✗ None |
| Web scanner | ✓ Free at /mcp | ✗ CLI only |
| Multi-registry | ✓ 6 registries | ✗ MCP only |
| Malicious signatures | ✓ 533 blocked | ✗ None |
| Open source | ✗ Proprietary | ✓ MIT license |
Which Should You Use?
Use MCP-Shield if:
- You need open-source code you can inspect and modify
- You're a developer who prefers CLI workflows
- You only need MCP server scanning, not other skill types
Use SkillShield if:
- You want to check skills before installing (pre-scanned directory)
- You need web-based scanning without CLI setup
- You scan across multiple registries (ClawHub, MCP, etc.)
- You want protection against known malware campaigns