---
title: Overview
description: Understand the role and boundaries of the Preferences package.
order: 1
toc:
  - id: package-role
    title: Package role
  - id: capabilities
    title: Capabilities
  - id: design-boundary
    title: Design boundary
---

## Package role {#package-role}

`@workspace/preferences` is a small React store for application preferences such as theme mode, navigation density, and compact layouts. It keeps the preference vocabulary owned by the consuming application.

## Capabilities {#capabilities}

- Extend the preference shape through TypeScript module augmentation.
- Hydrate a deterministic server snapshot with `useSyncExternalStore`.
- Persist typed `{ key, value }` updates through an application callback.
- Synchronize preferences with browser APIs through composable effects.
- Validate external updates from cookies, requests, forms, or message channels.

## Design boundary {#design-boundary}

The package does not define product-specific keys and does not select a persistence service. The application supplies its complete initial snapshot and decides how accepted changes are stored.