What problem does it solve? Environment variables are an invisible trust boundary: missing or malformed values like a database URL cause crashes mid-request instead of clear failures at startup. This Skill enforces a pattern where all env vars are parsed and validated once at boot, so configuration errors surface immediately with descriptive messages. ## Core Features & Use Cases - Boot-time validation with Zod: Define Server and Client schemas that parse process.env once and export a typed env object, throwing at module load if anything is missing or invalid. - Server/client separation: Keep server-only secrets out of the browser bundle by parsing the server schema only when window is undefined and restricting client code to NEXT_PUBLIC_* variables. - Per-runtime safety: Guidance for Node, Edge, and browser runtimes, including granular env-client and env-server imports for Edge routes. - Use Case: When adding a new STRIPE_SECRET_KEY to a Next.js app, add it to the Zod schema, update .env.example, and reference it via the typed env import instead of raw process.env. ## Quick Start Ask the agent to add a new environment variable to the project using the validated env schema pattern and update .env.example accordingly.
