Objective

Create a brand new Next.js app that satisfies all requested architecture and feature requirements. It includes App Router API endpoints, frontend pages, DDD structure, database integration, Google authentication with better-auth, tests, and linter. Keep the skill itself code-free: generate application code only inside the user-selected target folder.

Required Workflow

Follow this sequence exactly.

1) Ask Initial Questions First

Ask the user:

App name
Folder where the new app should be created
Database to use
Library to manage that database. When the user is unsure about the library, propose:

MongoDB: mongoose
DynamoDB: dynamoose
SQL dialects: prisma

Whether Jest or Vitest should be used as testing library
Whether ESLint or Oxlint should be used as linting library

Confirm the final choices before continuing.

2) Present Plan Before Implementation

Create a concrete implementation plan and present it to the user before changing files. Wait for explicit approval.

The plan must include:

Discovery confirmation
Version research and documentation review
Scaffolding
instrumentation.ts file setup to:
- Log the node version, next.js version and NODE_ENV variable at startup
- To validate the environment variables and log any critical missing ones at startup
- To initializate the database connection and log success or failure
- To log the server startup completion
Tactical DDD folder setup
Feature implementation
Tests
Linting setup, and Typescript configured in strict mode
Documentation updates
Final validation

3) Research Latest Versions and Official Docs

Before any installation, verify latest stable versions and usage from official sources:

Next.js docs: https://nextjs.org/docs
Next.js installation guide: https://nextjs.org/docs/app/getting-started/installation
better-auth docs
Chosen database library docs
Chosen testing library docs (Jest or Vitest)
Chosen linter library docs (ESLint or Oxlint)

Use the latest stable versions available at execution time. Do not assume versions from memory.

4) Scaffold the App with Latest Next.js Features

Create the app in the chosen folder with the chosen name and latest Next.js setup. Use current recommended options from Next.js docs, including App Router and src/ structure.

Install and configure:

better-auth (Google Auth)
Selected testing library
Selected linter library
Selected database library and required driver packages

5) Implement Required Tactical DDD Structure

Create the following structure:

<app_name>/src/__tests__
<app_name>/src/app
<app_name>/src/app/api
<app_name>/src/application
<app_name>/src/domain
<app_name>/src/infrastructure
<app_name>/src/shared
<app_name>/src/shared/logger
<app_name>/docs

6) Implement Required Features

Implement all of the following:

Database connection under src/infrastructure, aligned with the selected database and library
Example User entity in domain layer
User repository abstraction + implementation
Application service for user retrieval
GET /users endpoint in App Router under src/app/api
Homepage page with a Google Auth button powered by better-auth
Tests for domain/application/infrastructure/API behavior under src/__tests__

7) Environment and Documentation

Create:

.env.example with every required variable (app URL, auth values, Google OAuth credentials, DB settings, and anything else needed)
docs/endpoints.yaml listing available endpoints with method, path, purpose, and auth requirements in OpenAPI format

Update the app's README.md with setup, environment, run, test, lint, and endpoint usage instructions.

8) Validate and Iterate Until Complete

Run lint and tests. Fix failures and re-run until passing.

Verify:

App starts correctly
Homepage renders and auth button is present
/users endpoint works
Required structure and docs exist

If any requirement is unmet, iterate until complete.

Non-Negotiable Constraints

Keep all packages on latest stable versions at run time.
Do not embed generated app code in the skill itself.
Do not stop after scaffolding; continue until all requirements are satisfied and validated.

create-nextjs-ddd-auth-db