The Complete Production SOP: How to Deploy and Run env-schema & Fluent JSON Schema Environment Validation in Autonomous AI Agents

---
name: "env-schema-fluent-json-validation"
description: "Validate and parse process.env environment variables on application startup with JSON Schema."
metadata:
  author: "Fastify"
  version: "1.0.0"
  runtime_compatibility:
    - "codex"
    - "claude-code"
    - "cursor"
    - "windsurf"
triggers:
  - "validate process.env schema"
  - "env-schema type coercion"
  - "fail startup missing env"
permissions:
  fs_read: true
  fs_write: "workspace"
  shell_exec: false
  net_access: false
---

import S from 'fluent-json-schema';
import envSchema from 'env-schema';

const schema = S.object()
  .prop('NODE_ENV', S.string().enum(['development', 'testing', 'production']).default('development'))
  .prop('PORT', S.number().default(3000))
  .prop('DATABASE_URL', S.string().format(S.FORMATS.URI).required())
  .prop('CACHE_ENABLED', S.boolean().default(false))
  .valueOf();

export interface EnvConfig {
  NODE_ENV: 'development' | 'testing' | 'production';
  PORT: number;
  DATABASE_URL: string;
  CACHE_ENABLED: boolean;
}

export const config = envSchema<EnvConfig>({
  schema,
  dotenv: true
});

import { config } from './config/env';
import Fastify from 'fastify';

const server = Fastify({
  logger: config.NODE_ENV === 'development'
});

server.listen({ port: config.PORT, host: '0.0.0.0' }, (err, address) => {
  if (err) {
    server.log.error(err);
    process.exit(1);
  }
  console.log(`Server running at ${address} in ${config.NODE_ENV} mode`);
});