Add Environment Variable Skill

Add a new environment variable to .env.example and provide instructions for the manual updates needed in env.ts and CLAUDE.md.

Arguments

The user provides:

• Variable name (SCREAMING_SNAKE_CASE, e.g., STRIPE_SECRET_KEY)
• Description of what it's for
• Whether it's required or optional
• Default value (if any)
• Validation constraints (URL, min length, starts with prefix, etc.)

What This Skill Edits

Only .env.example — add the variable with a descriptive comment and placeholder value.

# Description of what this variable does
MY_VAR=your-value-here

# Stripe secret key (starts with sk_)
STRIPE_SECRET_KEY=sk_test_...

# Optional: Analytics tracking ID
# ANALYTICS_ID=

For optional variables, comment out the line so it's visible but not active by default.

What to Tell the User (do NOT edit these files)

After updating .env.example, inform the user they need to manually update two more files:

1. apps/api/src/lib/env.ts — Zod Validation

Tell the user to add the variable to the envSchema object. Provide the exact Zod line:

// Required string
MY_VAR: z.string().min(1),

// Required with constraint
STRIPE_SECRET_KEY: z.string().startsWith('sk_'),

// Required URL
WEBHOOK_URL: z.string().url(),

// Optional
ANALYTICS_ID: z.string().optional(),

// With default
MY_URL: z.string().url().default('http://localhost:3000'),

// Coerce to number
MAX_CONNECTIONS: z.coerce.number().default(10),

2. CLAUDE.md — Environment Variables Table

Tell the user to add a row:

| `MY_VAR` | Description | Yes/No |

Important Notes

• env.ts validates eagerly at import time — the app crashes immediately if a required variable is missing
• Tests must set process.env.VAR ??= 'dummy' BEFORE importing any module that imports env.ts
• If the variable is required, the test preload file also needs updating

Workflow

1. Read .env.example to see existing format
2. Add the variable with a descriptive comment and placeholder
3. Tell the user the exact lines to add to env.ts and CLAUDE.md
4. If variable is required, remind the user to update test preload too