Env Setup

Cross-Platform AI Agent Skill This skill works with any AI agent platform that supports the skills.sh standard.

Scan the codebase for environment variable usage, generate or update .env.example, validate .env completeness, and detect leaked secrets.

Anti-Hallucination Guidelines

CRITICAL: Only report variables that are actually found in the code:

1. Grep before reporting — Never invent variable names; only list what grep actually returns
2. Read .env.example before writing — Preserve existing entries; only add/update what changed
3. No actual secrets — .env.example must only contain placeholder values (e.g., your_api_key_here)
4. Verify .gitignore — Actually read the file before claiming .env is ignored

Workflow

Phase 1: Scan Codebase

Grep for environment variable patterns per language/framework:

Node.js / TypeScript:

grep -rE "process\.env\.([A-Z_][A-Z0-9_]*)" --include="*.ts" --include="*.js" --include="*.mjs" -h . \
  | grep -oE "process\.env\.[A-Z_][A-Z0-9_]*" | sort -u

Python:

grep -rE 'os\.environ\[["'"'"']([A-Z_][A-Z0-9_]*)["'"'"']\]|os\.getenv\(["'"'"']([A-Z_][A-Z0-9_]*)["'"'"']' \
  --include="*.py" -h . | grep -oE '[A-Z_][A-Z0-9_]+' | sort -u

Ruby:

grep -rE 'ENV\[["'"'"']([A-Z_][A-Z0-9_]*)["'"'"']\]' --include="*.rb" -h . \
  | grep -oE 'ENV\["[^"]*"\]' | grep -oE '"[^"]+"' | tr -d '"' | sort -u

Rust:

grep -rE 'env::var\("([A-Z_][A-Z0-9_]*)"\)' --include="*.rs" -h . \
  | grep -oE '"[A-Z_][A-Z0-9_]*"' | tr -d '"' | sort -u

Java / Kotlin:

grep -rE 'System\.getenv\("([A-Z_][A-Z0-9_]*)"\)' --include="*.java" --include="*.kt" -h . \
  | grep -oE '"[A-Z_][A-Z0-9_]*"' | tr -d '"' | sort -u

Framework-specific prefixes (scan for these in config files):

• NEXT_PUBLIC_* — Next.js client-exposed variables
• VITE_* — Vite client-exposed variables
• REACT_APP_* — Create React App client-exposed variables
• NUXT_PUBLIC_* — Nuxt.js public variables

Docker Compose:

grep -rE "^\s+- [A-Z_][A-Z0-9_]*=" docker-compose.yml docker-compose.*.yml 2>/dev/null \
  | grep -oE "[A-Z_][A-Z0-9_]*=" | tr -d "=" | sort -u

Also scan:

• .env.example (existing entries to preserve)
• config/ directory for config files referencing env vars
• Framework config files (next.config.js, vite.config.ts, etc.)

Phase 2: Categorize Variables

Group discovered variables by prefix/service:

Database:    DATABASE_URL, DB_HOST, DB_PORT, DB_NAME, DB_USER, DB_PASSWORD
Cache:       REDIS_URL, REDIS_HOST, REDIS_PORT
Auth:        JWT_SECRET, AUTH_SECRET, NEXTAUTH_SECRET, SESSION_SECRET
OAuth:       GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET, GITHUB_CLIENT_ID
Stripe:      STRIPE_SECRET_KEY, STRIPE_PUBLISHABLE_KEY, STRIPE_WEBHOOK_SECRET
AWS:         AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION, S3_BUCKET
Email:       SMTP_HOST, SMTP_PORT, SENDGRID_API_KEY, RESEND_API_KEY
App config:  NODE_ENV, PORT, BASE_URL, APP_URL
Client vars: NEXT_PUBLIC_*, VITE_*, REACT_APP_*

Classify each variable:

• Required vs Optional (required if no default/fallback in code)
• Secret vs Config (secret if it contains key/secret/password/token in name)
• Client-exposed (NEXT_PUBLIC_*, VITE_* — flag if contains secrets)

Phase 3: Compare with .env.example

Read existing .env.example (if it exists):

# Variables in code but NOT in .env.example (missing)
# Variables in .env.example but NOT in code (undocumented/stale)
# Variables in both (up to date)

Report:

• Missing vars (need to be added to .env.example)
• Stale vars (in .env.example but no longer used)
• Up-to-date vars

Phase 4: Generate / Update .env.example

For scan or sync operations:

Generate .env.example with:

• SCREAMING_SNAKE_CASE variable names
• Grouped by service (with section comments)
• Placeholder values for secrets, real defaults for config
• Type and description comments

Example output format:

# =============================================================================
# Database
# =============================================================================
DATABASE_URL=postgresql://user:password@localhost:5432/app_development
DB_HOST=localhost
DB_PORT=5432

# =============================================================================
# Authentication
# =============================================================================
# Generate with: openssl rand -hex 32
JWT_SECRET=your_jwt_secret_here
NEXTAUTH_SECRET=your_nextauth_secret_here

# =============================================================================
# Stripe (https://dashboard.stripe.com/apikeys)
# =============================================================================
STRIPE_SECRET_KEY=sk_test_your_key_here
STRIPE_PUBLISHABLE_KEY=pk_test_your_key_here
STRIPE_WEBHOOK_SECRET=whsec_your_webhook_secret_here

# =============================================================================
# App Config
# =============================================================================
NODE_ENV=development
PORT=3000
BASE_URL=http://localhost:3000

Rules:

• Never include real values from .env — only placeholders
• Preserve existing comments and groupings in .env.example
• When updating, only add missing variables; do not reorder existing ones

Phase 5: Validate .env (if validate subcommand or .env exists)

Read .env and check:

1. Missing required variables: Every variable in code without a default/fallback must be set
2. Empty values: VAR= with no value is suspicious for required vars
3. Stale variables: Present in .env but not found in codebase scan
4. .gitignore check: Verify .env (and .env.local) are in .gitignore

grep -E "^\.env" .gitignore 2>/dev/null

Warn clearly if .env is NOT in .gitignore.

Phase 6: Secret Detection (if --check-secrets)

Scan .env for high-entropy strings and known secret patterns:

# Check for common secret patterns
grep -iE "(password|secret|api_key|private_key|token|auth_key)\s*=\s*['\"]?[a-zA-Z0-9+/]{20,}" .env 2>/dev/null

Check git history for leaked secrets:

git log --all --full-history --diff-filter=A -p -- .env 2>/dev/null | grep -iE "(password|secret|key)\s*=" | head -20

Flag client-exposed secrets:

• Check NEXT_PUBLIC_*, VITE_*, REACT_APP_* variables
• If any contain "secret", "key", "password", "token" in the name — warn loudly

Recommend pre-commit tools:

• detect-secrets (Python): pip install detect-secrets && detect-secrets scan > .secrets.baseline
• gitleaks: gitleaks detect --source=.

Argument Parsing

• scan (default): Scan codebase, generate/update .env.example
• validate: Validate .env against discovered variables
• sync: Sync .env.example to match current codebase (add missing, mark stale)
• --check-secrets: Enable secret detection in .env and git history

Important Notes

• NEVER include real secrets in .env.example — only placeholder values
• Client-exposed vars (NEXT_PUBLIC_*, VITE_*) are bundled into the frontend — never put secrets there
• .env must be gitignored — always verify and warn if not
• Historical leaks matter — even if .env is gitignored now, it may have been committed in the past
• Stale variables in .env can be security risks — document and remove unused ones

Examples

# Scan codebase and generate .env.example
/env-setup

# Scan with explicit subcommand
/env-setup scan

# Validate existing .env completeness
/env-setup validate

# Sync .env.example with current codebase
/env-setup sync

# Full scan + secret detection
/env-setup scan --check-secrets