Medusa Security Skill

Medusa Security Skill

Identity

AI-first security scanner integration skill. Leverages Medusa's 76 scanners and 3,000+ detection patterns for comprehensive security analysis including AI/​ML-specific vulnerability detection.

Capabilities

1. Full Scan — All 76 scanners, comprehensive security analysis
2. AI-Only Scan — Prompt injection, MCP security, agent security, RAG security
3. Quick Scan — Git-changed files only for rapid development feedback
4. Targeted Scan — Specific scanner categories (mcp, secrets, prompt-injection, etc.)
5. SARIF Output Parsing — Standard SARIF v2.1.0 structured findings
6. JSON Output Parsing — Medusa-native JSON format
7. OWASP Mapping — Maps findings to OWASP Agentic AI (ASI01-10) and OWASP Top 10 (A01-10)
8. Remediation Guidance — Links findings to agent-studio skills and agents
9. CI/​CD Integration — Fail-on thresholds, SARIF upload for GitHub Code Scanning

Prerequisites

Python 3.10+
pip install medusa-security

Check installation: python -m medusa --version

Workflow: Full Security Scan

# Step 1: Verify installation
python -m medusa --version

# Step 2: Run scan
medusa scan . --format sarif --fail-on high

# Step 3: Parse output (use scripts/​main.cjs)
node .claude/​skills/​medusa-security/​scripts/​main.cjs --mode full --target .

# Step 4: Review findings by severity
# CRITICAL → immediate fix required
# HIGH → fix before release
# MEDIUM → fix in next sprint
# LOW → track and address

Workflow: AI-Only Scan

medusa scan . --format sarif --ai-only

Scans only: prompt injection (800+ patterns), MCP security (400+ patterns), agent security (500+ patterns), RAG security (300+ patterns).

Workflow: Quick Scan (Development)

medusa scan . --format sarif --quick

Only scans git-changed files. Use during development for rapid feedback.

Workflow: Targeted Scan

# MCP security only
medusa scan . --format sarif --scanners mcp-server,mcp-config

# Secrets only
medusa scan . --format sarif --scanners secrets,gitleaks,env

# AI context files only
medusa scan . --format sarif --scanners ai-context

Output Processing

The skill uses helper scripts located at .claude/​skills/​medusa-security/​scripts/:

Using the Pipeline

# Full scan with structured output
node .claude/​skills/​medusa-security/​scripts/​main.cjs --mode full --target .

# AI-only scan
node .claude/​skills/​medusa-security/​scripts/​main.cjs --mode ai-only --target .

# Quick scan (git-changed files)
node .claude/​skills/​medusa-security/​scripts/​main.cjs --mode quick --target .

Deterministic Security Review (Recommended in Claude sessions)

Use this when you need the final security review report and want to avoid recursive Glob timeouts:

node .claude/​skills/​medusa-security/​scripts/​security-review.cjs

This writes:

/​.claude/​context/​reports/​security/​security-review-medusa-scan-2026-02-17.md

and performs fixed-path checks on:

• .claude/​hooks/
• .claude/​lib/
• .claude/​skills/​medusa-security/​scripts/
• .claude/​CLAUDE.md

Important Runtime Guardrail

• Avoid recursive glob patterns like .claude/​skills/​medusa-security/​**/​* in long sessions.
• Prefer direct file reads and deterministic script entry points.

OWASP Mapping

Findings are automatically mapped to:

• OWASP Agentic AI Top 10 (ASI01-10): Goal Hijacking, Tool Misuse, Context Poisoning, etc.
• OWASP Top 10 (A01-10): Broken Access Control, Injection, Cryptographic Failures, etc.

Severity Triage

Agent Integration

CI/​CD Integration

# GitHub Actions example
- name: Security Scan
  run: |
    pip install medusa-security
    medusa scan . --format sarif --fail-on high -o reports/
- name: Upload SARIF
  uses: github/​codeql-action/​upload-sarif@v3
  with:
    sarif_file: reports/​medusa-results.sarif

Iron Laws

1. ALWAYS verify Medusa installation before scanning — python -m medusa --version first; a missing install produces no output instead of an error, silently masking all vulnerabilities.
2. NEVER rely on AI-only mode as the release gate — AI-only mode misses traditional SAST patterns (SQLi, XSS, path traversal); full scan covering all 76 scanners is required for release-gate decisions.
3. ALWAYS set --fail-on high in CI/​CD pipelines — without a fail threshold, pipelines pass even when CRITICAL findings exist, creating false confidence in the security posture.
4. NEVER skip SARIF upload to GitHub Code Scanning — local-only SARIF is lost after the build; uploading via github/​codeql-action/​upload-sarif@v3 persists findings for PR review, trend tracking, and compliance audit trails.
5. ALWAYS fix CRITICAL and HIGH findings before merging — deploying with unresolved high-severity findings expands the attack surface and nullifies the security posture gain from scanning.

Anti-Patterns

Memory Protocol

After scanning:

• Record new vulnerability patterns in patterns.json
• Log significant findings in issues.md
• Track scan history for trend analysis
• Use recordGotcha() for recurring false positives

const manager = require('.claude/​lib/​memory/​memory-manager.cjs');

manager.recordGotcha({
  text: 'False positive: medusa flags X pattern in Y context',
  area: 'security-scanning',
});

manager.recordPattern({
  text: 'Prompt injection found in CLAUDE.md context files',
  area: 'ai-security',
});

Related Skills

• security-architect — Threat modeling and OWASP analysis
• static-analysis — CodeQL and Semgrep SARIF analysis
• semgrep-rule-creator — Create custom Semgrep rules
• insecure-defaults — Detect hardcoded credentials
• variant-analysis — Discover vulnerability variants