# Extension Point Chooser Use this page before adding a hook, service provider call, or package integration. Start with the table that matches the runtime you are changing, then follow the linked page for the full contract and examples. ## Core And Package Runtime | Need | Use | Owner | | -------------------------------------- | ----------------------------------------------------------------------------------------- | --------------------- | | Register a page subject type | `CapellCore::registerPageType(new PageTypeData(...))` | Core | | Replace a core model implementation | Laravel container binding for the model class | Core | | Register renderable definitions | `RenderableRegistry::register(...)` | Core | | Register link picker/search options | `LinkableContentRegistry::register(...)` | Core | | Register content graph extractors | `ContentGraphRegistry::register(...)` or `ContentGraphRegistry::TAG` | Core | | Add package settings | `SettingsSchemaRegistry::register()`, `registerSettingsClass()`, and `registerMetadata()` | Core/Admin | | Add package settings migrations | `database/settings/*` plus package install/setup registration | Core | | Add developer-tooling makers | `MakerRegistryInterface::register(...)` | Core | | Load vendor build assets conditionally | `VendorAssetConditionRegistry::register(...)` | Core/Frontend | | Add static export files | `StaticSiteExtensionRegistry::register(...)` | Static export package | | Extend ownership/export mapping | `OwnershipMap::register(...)` | Exchanger | ## Admin Runtime | Need | Use | Owner | | ------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------- | ----- | | Add admin resources, pages, widgets, configurators, user menu items, settings, or extenders from one package | `AdminBridge` and `AdminBridgeRegistrar` | Admin | | Add one small admin surface | `CapellAdmin::contributeToAdminSurface(AdminSurfaceContributionData::...)` | Admin | | Register a package settings/control page on Extensions | `CapellAdmin::registerExtensionPage(...)` | Admin | | Add dashboard widgets | `CapellAdmin::registerDashboardWidget(...)` | Admin | | Add small dashboard metrics | `CapellAdmin::registerOverviewStat(...)` | Admin | | Replace the dashboard page | `AdminBridgeRegistrar::dashboardPage(...)` or `CapellAdmin::useDashboardPage(...)` | Admin | | Add user menu actions | `CapellAdmin::registerUserMenuItem(...)` | Admin | | Add admin header tools | Tag an `AdminToolItem` with `AdminToolItem::TAG` | Admin | | Add welcome tour steps | `CapellAdmin::registerWelcomeTourStep(...)` | Admin | | Add navigation groups | `CapellAdmin::registerNavigationGroup(...)` | Admin | | Add content widgets | `CapellAdmin::registerWidget(...)` or `registerDiscoverableWidgets(...)` | Admin | | Add fields to page, site, layout, or user forms | Tagged schema extenders such as `PageSchemaExtender::TAG` | Admin | | Add page/site/resource header actions | Tagged action extenders such as `PageHeaderActionExtender::TAG` | Admin | | Modify page, user, or resource tables | Tagged table extenders such as `PageTableExtender::TAG` | Admin | | Extend the installed Extensions page | `ExtensionsPageActionRegistry` or `ExtensionsPageExtender::TAG` | Admin | | Subscribe to admin serving events | `CapellAdmin::serving(...)` | Admin | | Register activity display/revert behavior | `ActivityChangeSetBuilder::TAG` and `ActivityRevertHandler::TAG` | Admin | ## Frontend Runtime | Need | Use | Owner | | ---------------------------------------- | ------------------------------------------------------------------------ | ------------- | | Inject small public HTML | `RenderHookRegistry::register(...)` | Frontend | | Add public widgets | `WidgetRegistry::register(...)` with a frontend target | Frontend/Core | | Register frontend component aliases | `FrontendComponentRegistry::register(...)` | Frontend | | Register package CSS or JS sources | `TailwindAssetsRegistry::registerSource()` / `registerImport()` | Core/Frontend | | Register critical or deferred assets | `CriticalAssetRegistry::registerCritical()` / `registerDeferred()` | Frontend | | Reserve package-owned public paths | `ReservedFrontendPathRegistry::reserveExact()` / `reservePrefix()` | Frontend | | Add middleware to the public page route | `FrontendRouteMiddlewareRegistry` | Frontend | | Add frontend rule conditions | `FrontendRuleConditionRegistry::register(...)` | Frontend | | Replace response rendering for a runtime | `FrontendResponseRendererRegistry::register(...)` / `registerClass(...)` | Frontend | | Invalidate pages when a model changes | `CacheInvalidationRegistry::registerDependency(...)` | Frontend | ## Rules - Prefer an existing extension point over patching host package classes. - Keep package feature logic in the package. Host packages should expose contracts, not product behavior. - Put writes in Actions and structured state in Data objects. - Keep visible strings in translations. - Public output must pass the [public HTML safety contract](../frontend/public-html-safety.md). - Register most extension points from a package provider's `boot()` method unless the contract explicitly says to bind something in `register()`. ## Next - [Package authoring](README.md) - [Extension point API reference](extension-point-api-reference.md) - [Admin extensions](admin-extensions.md) - [Frontend extensions](frontend-extensions.md) - [Extension troubleshooting](extension-troubleshooting.md)