Need guidance on extending Prisma adapter while maintaining core functionality

[kissngg]

Adapter type

@auth/prisma-adapter

Environment

next: 15.0.3
react: 19.0.0-rc
@auth/core: 0.37.4
@prisma/client: 5.22.0
prisma: 5.22.0
OS: wsl ubuntu 24
Node: v22

Reproduction URL

Describe the issue
I want to use the Prisma adapter while keeping my existing database schema and relationships.

Currently, I have a more complex database schema than the basic Auth.js schema, with additional fields and relationships. I'd like to find a way to use the Prisma adapter while maintaining these custom fields/relations, rather than creating a completely custom adapter from scratch.

I've tried:

1. Adding fields to the basic Prisma adapter schema
2. Looking for examples of extended Prisma adapters
3. Reading through the documentation

But I haven't found clear guidance on how to extend the Prisma adapter while maintaining its core functionality.

Would like to understand:

1. If it's possible to extend the Prisma adapter without creating a custom adapter
2. Best practices for adding custom fields/relations while using the Prisma adapter
3. Any recommended approaches for this use case

Reproduce

1. Have an existing Prisma schema with custom fields/relations
2. Try to integrate Auth.js Prisma adapter while maintaining existing schema structure
3. Face difficulties in extending the adapter while keeping core functionality