# PLEX

> An agentic framework for building apps out of plugins.

## Start here

- [Overview](https://dxos.org/docs/plex/overview.md): What PLEX is, how an app is made of plugins, and Composer as the app built on it.
- [Why PLEX?](https://dxos.org/docs/plex/why-plex.md): Why an app made of plugins, where a third-party plugin has the same powers as a built-in one.
- [Build with a coding agent](https://dxos.org/docs/plex/build-with-a-coding-agent.md): Have Claude Code, Codex or Cursor build a plugin and load it into your Composer, from a prompt you can edit first.

## Learning path

- [The PLEX plugin](https://dxos.org/docs/plex/learn/the-plex-plugin.md): What a plugin is, and the plugin the learning path builds, running in the plugin inspector.
- [Create a plugin](https://dxos.org/docs/plex/learn/create-plugin.md): Start the tutorial plugin: its metadata, its first module and its translations.
- [Define a type](https://dxos.org/docs/plex/learn/define-type.md): Give the plugin its own ECHO type.
- [Add an operation](https://dxos.org/docs/plex/learn/add-operation.md): Give the plugin an action that the UI, the command palette and agents can run.
- [Extend the App Graph](https://dxos.org/docs/plex/learn/extend-app-graph.md): Put the plugin's objects and actions into the app's navigation.
- [Add a surface](https://dxos.org/docs/plex/learn/add-surface.md): Render the plugin's objects by contributing a surface.
- [Run it in Composer](https://dxos.org/docs/plex/learn/run-in-composer.md): Load the plugin from its dev server into Composer Preview, and use it there.
- [Publishing a plugin](https://dxos.org/docs/plex/publishing-plugins.md): Publish the finished plugin to your private registry, where Composer lists it only to you.

## Core concepts

- [Plugins and modules](https://dxos.org/docs/plex/concepts/plugins.md): A plugin is metadata plus modules, and an app is the plugins it loads.
- [Capabilities](https://dxos.org/docs/plex/concepts/capabilities.md): Typed contributions that modules provide and request, which is how plugins extend each other.
- [Activation](https://dxos.org/docs/plex/concepts/activation.md): When a module runs: the events that activate it and the order the plugin manager follows.
- [Operations](https://dxos.org/docs/plex/concepts/operations.md): Named, typed actions that the UI, the command palette and agents all run the same way.
- [Surfaces](https://dxos.org/docs/plex/concepts/surfaces.md): How the framework decides which component renders an object in a given place.

## Guides

- [Effect](https://dxos.org/docs/plex/guides/effect.md): Use Effect services and layers from a plugin's modules.
- [Testing](https://dxos.org/docs/plex/guides/testing.md): Test a plugin's modules without an app, with the App Framework test harness.
- [Debugging](https://dxos.org/docs/plex/guides/debugging.md): Find out why a module did not activate or a contribution did not show.
- [App capabilities](https://dxos.org/docs/plex/guides/app-capabilities.md): The capabilities a workspace app such as Composer adds for plugins to contribute, from the App Toolkit.
- [Settings and state](https://dxos.org/docs/plex/guides/settings-and-state.md): Keep a plugin's settings, which sync, apart from its device state, which does not.
- [App Graph](https://dxos.org/docs/plex/guides/app-graph.md): The graph of nodes and actions that an app's navigation and menus are built from, and how a plugin adds to it.
- [React](https://dxos.org/docs/plex/guides/react.md): The React hooks for plugins.
- [ECHO](https://dxos.org/docs/plex/guides/using-echo.md): Register a plugin's ECHO types with the app, so it can create, name and list their objects.

## API

- [Plugin](https://dxos.org/docs/plex/guides/plugin.md): Define a plugin and its modules.
- [Capability](https://dxos.org/docs/plex/guides/capability.md): Declare, contribute and request capabilities, including the built-in ones.
- [ActivationEvent](https://dxos.org/docs/plex/guides/activation-event.md): Declare activation events and use the built-in ones.
- [PluginManager](https://dxos.org/docs/plex/guides/plugin-manager.md): Create the plugin manager, and add, enable and remove plugins.
- [Operation](https://dxos.org/docs/plex/guides/operation.md): Define operations, implement their handlers and invoke them.
- [Surface](https://dxos.org/docs/plex/guides/surface.md): Contribute surfaces and render other plugins' surfaces.

## Resources

- [API reference](https://dxos.org/docs/plex/resources/api-reference.md): Generated API reference for PLEX.
- [Glossary](https://dxos.org/docs/plex/resources/glossary.md): Every Composer and PLEX term, defined once.
- [llms.txt](https://dxos.org/docs/plex/resources/llms-txt.md): The PLEX site map and full text for agents, in the llms.txt format.