Security Skill

Load with: base.md

Security best practices and automated security testing for all projects.

Core Principle

Security is not optional. Every project must pass security checks before merge. Assume all input is malicious, all secrets will leak if committed, and all dependencies have vulnerabilities.

Required Security Setup

1. Gitignore (Non-Negotiable)

Every project must have these in .gitignore:

# Environment files - NEVER commit
.env
.env.*
!.env.example

# Secrets
*.pem
*.key
*.p12
*.pfx
credentials.json
secrets.json
*-credentials.json
service-account*.json

# IDE and OS
.idea/
.vscode/settings.json
.DS_Store
Thumbs.db

# Dependencies
node_modules/
__pycache__/
*.pyc
.venv/
venv/

# Build outputs
dist/
build/
*.egg-info/

# Logs that might contain sensitive data
*.log
logs/

2. Environment Variables

Create .env.example with all required vars (no values):

# .env.example - Copy to .env and fill in values

# Server-side only (NEVER prefix with VITE_ or NEXT_PUBLIC_)
DATABASE_URL=
ANTHROPIC_API_KEY=
SUPABASE_SERVICE_ROLE_KEY=

# Client-side safe (public, non-sensitive)
VITE_SUPABASE_URL=
VITE_SUPABASE_ANON_KEY=

Frontend Environment Variables (Critical!)

NEVER put secrets in client-exposed env vars:

// WRONG - Secret exposed to browser bundle!
const apiKey = import.meta.env.VITE_ANTHROPIC_API_KEY;

// CORRECT - Only public values client-side
const supabaseUrl = import.meta.env.VITE_SUPABASE_URL;

// CORRECT - Secrets stay server-side only
// In API route or server function:
const apiKey = process.env.ANTHROPIC_API_KEY;

Vercel Environment Variables:

• In Vercel dashboard, secrets without VITE_ prefix are server-only
• Only VITE_* vars are bundled into client code
• Always verify in browser devtools → Sources → your bundle that secrets aren't exposed

Validate environment at startup:

// config/env.ts
import { z } from 'zod';

const envSchema = z.object({
  DATABASE_URL: z.string().url(),
  ANTHROPIC_API_KEY: z.string().min(1),
  NODE_ENV: z.enum(['development', 'production', 'test']),
});

export const env = envSchema.parse(process.env);

# config/env.py
from pydantic_settings import BaseSettings

class Settings(BaseSettings):
    database_url: str
    anthropic_api_key: str
    environment: str = "development"

    class Config:
        env_file = ".env"

settings = Settings()

Security Tests

Pre-Commit Security Checks

Add to pre-commit hooks:

For all projects:

# .pre-commit-config.yaml (add to existing)
repos:
  # Detect secrets
  - repo: https://github.com/Yelp/detect-secrets
    rev: v1.4.0
    hooks:
      - id: detect-secrets
        args: ['--baseline', '.secrets.baseline']

  # Check for security issues in dependencies
  - repo: local
    hooks:
      - id: security-check
        name: security-check
        entry: ./scripts/security-check.sh
        language: script
        pass_filenames: false

TypeScript/JavaScript:

// package.json scripts
{
  "scripts": {
    "security:audit": "npm audit --audit-level=high",
    "security:secrets": "npx secretlint '**/*'",
    "security:deps": "npx better-npm-audit audit"
  }
}

Python:

# Add to dev dependencies
pip install safety bandit

# Commands
safety check           # Check dependencies for vulnerabilities
bandit -r src/        # Static security analysis

Security Check Script

Create scripts/security-check.sh:

#!/bin/bash
set -e

echo "Running security checks..."

# Check for secrets in staged files
echo "Checking for secrets..."
if command -v detect-secrets &> /dev/null; then
  detect-secrets scan --baseline .secrets.baseline
fi

# Check .env is not staged
if git diff --cached --name-only | grep -E '^\.env$|^\.env\.' | grep -v '\.example$'; then
  echo "ERROR: .env file is staged for commit!"
  exit 1
fi

# Check for common secret patterns in staged files
STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM)
if echo "$STAGED_FILES" | xargs grep -l -E '(password|secret|api_key|apikey|token|private_key)\s*[:=]\s*["\047][^"\047]+["\047]' 2>/dev/null; then
  echo "ERROR: Possible secrets found in staged files!"
  exit 1
fi

# Language-specific checks
if [ -f "package.json" ]; then
  echo "Checking npm dependencies..."
  npm audit --audit-level=high || echo "Warning: npm audit found issues"
fi

if [ -f "pyproject.toml" ] || [ -f "requirements.txt" ]; then
  echo "Checking Python dependencies..."
  if command -v safety &> /dev/null; then
    safety check || echo "Warning: safety found issues"
  fi
fi

how to use security
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use security on Cursor
AI-first code editor with Composer
1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add security
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/alinaqi/claude-bootstrap --skill securitycopy
The skills CLI fetches security from GitHub repository alinaqi/claude-bootstrap and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
│   • Antigravity
│   • Cline
│   • Codex
│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/security
Reload or restart Cursor to activate security. Access the skill through slash commands (e.g., /security) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?