add-env-var

name	add-env-var
description	Add a new environment variable to the backend the right way — boot-time validation, .env.example documentation, and typed access. Use when introducing any new backend config/secret/flag.

Add a backend env var

Backend env is validated at boot (fail-fast) in src/config/env.validation.ts. A misconfigured/missing required var must crash startup, not fail silently later.

Steps

1. Declare + validate in src/config/env.validation.ts on the EnvironmentVariables class:
   • Required: @IsString() (no @IsOptional). Add stronger checks where it matters: @MinLength(32) for keys, @IsUrl(...), @IsNumber(), @IsEnum(...).
   • Optional: add @IsOptional() and a sensible default (= '...').
   • Add a one-line comment explaining what it's for / how to generate it.
2. Document in .env.example with a comment and a working dev placeholder. ⚠️ If the var is required, the placeholder MUST satisfy validation so a fresh cp .env.example .env boots (e.g. a ≥32-char string for a key). Mark clearly to change it for prod.
3. Access via ConfigService.get<T>('NAME') (injected), or process.env.NAME in non-DI spots (guards/services already do this) — handle the not-configured case (fail-closed in production where it's a security control).
4. Secrets: never log them; if it's a token/credential consider encrypting at rest (EncryptionService). Ensure it's covered by .gitignore if it lands in a file.
5. Update backend/AGENTS.md's "Required env" list if the var is required.
6. Verify (from backend/): bunx tsc -p tsconfig.build.json --noEmit.

Mobile public config goes in app.config.ts / src/constants/config.ts via EXPO_PUBLIC_* (never put secrets in the mobile bundle).