> For the complete documentation index, see [llms.txt](https://prisma-util.gitbook.io/stable/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prisma-util.gitbook.io/stable/modules/core.md).

# Prisma Util Core

The Core module makes exception of the module rules and is used to generate middleware and extensions only.

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## Project Toolchain Usage

This feature makes use of these Project Toolchain APIs: **Middleware**, **Extensions**. Because of this usage, it defines the following modules:

### core

This module defines the following middleware and extensions identifiers that can be imported via Project Toolchain, along with their descriptions:

* **defaultValue** - Allows setting of default values using `PrismaClient.$$default`.
  {% endhint %}

The Prisma Util Core module is a virtual module (meaning that it can't be imported and doesn't have any root-level files) that exports middleware and extensions that are generated by default.