Auth.js Google OAuth Setup

What does this kit do?

Add Google sign-in to a clean Next.js 15 or 16 app, calculate the correct callback URLs, and stop for the human-owned Google setup step.

Who should use it?

• The target is a clean Next.js 15 or 16 application.
• The app uses or is ready to add Auth.js in the supported layout.
• A human can create the Google OAuth client and enter its credentials.

What will it change?

• The supported Auth.js provider configuration and related application files.
• The local environment template with variable names only, never credential values.

What will the human approve?

The human approves the application file changes, creates the Google OAuth client, and supplies the credentials through the protected setup path.

What does it verify?

• The application matches the supported Next.js and Auth.js shape.
• The configured callback URLs match the local and deployed application origins provided by the human.

What can it remove?

• Supported file changes created by that exact run when they have not been changed afterward.

What does it deliberately not do?

• The application has a custom or unsupported authentication architecture.
• The target is not a supported Next.js version.
• The agent would need to create or own the Google OAuth client.
• The Google OAuth client, human-owned credentials, or changes made later.
• Custom authentication code outside the approved plan.

How does an agent use it?

1. Open the BoxFetch Original in the BoxFetch app.
2. Let the kit inspect the target without making changes.
3. Review the plan, target, and human checkpoint.
4. Approve only the changes you intend to make.
5. Read the verification result and run record.

How do I use it?

Create a BoxFetch account and open the app to see current beta availability. The six current Originals are free during the controlled beta, while the application remains the authority for live access.