# Extension Point API Reference Use this page when you know what you want to extend and need the exact contract, registration point, and fallback behavior. Start with [Extension point chooser](extension-point-chooser.md) if you are still deciding. ## Reading The Tables | Column | Meaning | | ------------- | ---------------------------------------------------------------------------- | | API | Contract, registry, facade, or tag to use. | | Register from | Where package code should usually register it. | | Called by | Runtime surface that consumes the contribution. | | Safe fallback | What should happen when the package is absent, disabled, or returns nothing. | | Test recipe | Smallest useful proof. | ## Core And Package Runtime | Need | API | Register from | Called by | Safe fallback | Test recipe | | ------------------------ | ------------------------------------------------------------------- | ------------------------------------------------------ | ------------------------------------------------------------- | ------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------- | | Page subject type | `CapellCore::registerPageType(new PageTypeData(...))` | Runtime provider `registeringPackage()` or boot method | Blueprint/page type selection | Type is absent from selectors | Assert `CapellCore::getPageTypes()` contains the key. | | Model morph alias | `CapellCore::registerModel()` / `registerModels()` | Runtime provider | Morph map and model resolution | Laravel default morph behavior | Assert morph map resolves the model alias. | | Model behavior | `CapellCore::registerModelInterceptor()` | Runtime/admin provider | Capell model interceptor resolver | Base model behavior remains unchanged | Instantiate model and assert interceptor method affects only matching context. | | Settings schema | `SettingsSchemaRegistry::register()` plus `registerSettingsClass()` | Runtime/admin provider or AdminBridge | Admin settings surfaces | Group/tab is absent | Resolve registry and assert schema/settings class for group. | | Package settings page | `CapellAdmin::registerExtensionPage()` | AdminBridge or admin provider | Installed Extensions page and grouped Filament sub-navigation | No package control page | Assert `ExtensionPageRegistry::get($packageName)` returns the page and the sub-navigation contains accessible registered pages grouped by product group. | | Content graph extraction | `ContentGraphRegistry::TAG` or registry registration | Runtime provider | Content graph builders | Content is not linked into graph | Build graph for fixture content and assert edge exists. | | Link picker entries | `LinkableContentRegistry::register(...)` | Runtime/admin provider | Link picker/search UI | Item type is not searchable | Assert registry includes provider and search returns fixture. | | Renderable definition | `RenderableRegistry::register(...)` | Runtime provider | Rendering/runtime builders | Definition is unavailable | Assert registry returns the definition key. | | Tailwind assets | `TailwindAssetsRegistry::registerSource()` / `registerImport()` | Runtime/frontend provider | Frontend/admin asset commands | Package classes are not scanned | Assert `toReport()` includes source/import origin. | | Vendor asset condition | `VendorAssetConditionRegistry::register(...)` | Runtime provider | Asset manifest builders | Asset is not conditionally loaded | Assert condition returns expected value for fixture context. | | Developer maker | `MakerRegistryInterface::register(...)` | Runtime/dev provider | Maker commands | Maker command option is absent | Assert maker appears in registry. | ## Admin Runtime | Need | API | Register from | Called by | Safe fallback | Test recipe | | ---------------------------------- | ----------------------------------------------------------------------------------------------------- | ----------------------------------- | ------------------------------- | ------------------------------------- | ------------------------------------------------------------ | | Multiple admin surfaces | `AdminBridge` with `AdminBridgeRegistrar` | Runtime/admin provider | Admin bridge registry | Package contributes no admin surfaces | Assert bridge is registered for package name. | | Single admin page/resource/widget | `CapellAdmin::contributeToAdminSurface(AdminSurfaceContributionData::...)` | Admin provider | `CapellAdminPlugin` | Surface is absent | Assert admin surface lookup contains the class. | | Dashboard widget | `CapellAdmin::registerDashboardWidget(...)` | Admin provider or bridge | Dashboard widget resolver | Widget hidden | Assert widget appears in expected dashboard slot. | | Overview stat | `CapellAdmin::registerOverviewStat(...)` | Admin provider | Dashboard stats | Stat hidden | Assert stat key appears for allowed user/context. | | User menu item | `CapellAdmin::registerUserMenuItem(...)` | Admin provider | User menu registry | Menu item hidden | Assert user menu registry contains item. | | Admin header tool | `AdminToolItem::TAG` | Tag class in provider | Admin tool registry | Tool hidden | Resolve `app()->tagged(AdminToolItem::TAG)`. | | Page form fields | `PageSchemaExtender::TAG` | Tag extender in provider or bridge | Page schema resolver | Base page form only | Build schema for fixture page and assert field exists. | | Site form fields | `SiteSchemaExtender::TAG` | Tag extender in provider or bridge | Site schema resolver | Base site form only | Build schema for fixture site and assert field exists. | | Layout form fields | `LayoutSchemaExtender::TAG` | Tag extender in provider or bridge | Layout schema resolver | Base layout form only | Build schema for fixture layout and assert field exists. | | User form fields | `UserSchemaExtender::TAG` | Tag extender or user bridge | User schema resolver | Base user form only | Assert `supports()` and schema field for target user model. | | Page table query | `PageTableExtender::TAG` | Tag extender in provider | Page tables and page selects | Base query | Assert modified query includes expected relation/filter. | | Page table publish/workflow status | `PageTableStatusResolver` container binding | Admin provider | Pages table status column | Publish-date status resolver | Bind a fake resolver and assert the table renders its state. | | User table query | `UserTableExtender::TAG` | Tag extender or user bridge | User resource table | Base query | Assert modified query behavior. | | Header actions | `PageHeaderActionExtender::TAG`, `SiteHeaderActionExtender::TAG`, `ResourceHeaderActionExtender::TAG` | Tag extender in provider | Resource/page action resolvers | Action hidden | Render header actions and assert action key. | | Site row actions | `SiteRecordActionExtender::TAG` | Tag extender in provider | Sites table | Action hidden | Render table actions for fixture site. | | Publish panel content | `PublishPanelExtender::TAG` | Tag extender in provider | Page publish section | Panel remains unchanged | Assert view/html appears only for supported page. | | Page edit content | `PageEditExtender::TAG` | Tag extender in provider | Edit page | Extra content hidden | Render edit page and assert component appears. | | Page resource pages/widgets | `PageResourcePageExtender::TAG`, `PageResourceWidgetExtender::TAG` | Tag extender in provider | Page resource | Extra pages/widgets hidden | Assert `PageResource` includes class. | | Page export fields | `PageExportExtender::TAG` | Tag extender in provider | Page/site export actions | Extra fields omitted | Run export action and assert payload contains field. | | Media edit actions | `MediaEditActionExtender::TAG` | Tag extender in provider | Media edit page | Action hidden | Render media edit actions. | | Extensions page content | `ExtensionsPageExtender::TAG` | Tag extender in provider | Installed Extensions page | No package alert/content | Render Extensions page and assert package section. | | Extensions page actions | `ExtensionsPageActionRegistry` | `afterResolving()` or provider boot | Installed Extensions page | Action hidden | Resolve registry and assert header/table action key. | | Admin panel customization | `AdminPanelExtender::TAG` | Tag extender in provider | `CapellAdminPlugin` | Base panel config | Build panel and assert plugin/middleware/theme change. | | Validation gates | `ValidationSubscriber` or subscriber contracts | Runtime/admin provider | Subscriber manager/admin events | Validation not applied | Notify event with fixture and assert error/result. | | Admin event handlers | `AdminEventRegistry::register(...)` | Admin provider | `HasDynamicEventListeners` | Event has no extra handler | Dispatch Livewire event and assert handler ran. | | Activity display/revert | `ActivityChangeSetBuilder::TAG`, `ActivityRevertHandler::TAG` | Admin provider | Activity/revert actions | Default activity behavior | Run activity builder/revert fixture. | | Site Health report | `SiteHealthReportExtender::TAG` | Admin provider | Site Health action/page | Report section absent | Build Site Health report and assert section. | ## Frontend Runtime | Need | API | Register from | Called by | Safe fallback | Test recipe | | ----------------------------- | ------------------------------------------------------------------ | ---------------------------------------- | --------------------------------- | ------------------------------------ | ------------------------------------------------------------------ | | Small public HTML injection | `RenderHookRegistry::register(...)` | Frontend/runtime provider | Public Blade hook calls | Hook outputs nothing | Render anonymous page and assert safe HTML. | | Frontend component alias | `FrontendComponentRegistryInterface::register(...)` | Frontend provider | Runtime component resolver | Alias is unavailable | Assert `has()` and `hasReference()` for key/alias. | | Builder block rendering | `WidgetRegistry::register(...)` with frontend target | Runtime/frontend provider | Content renderer | Block is skipped/unrenderable | Render fixture block and assert output. | | Reserved public path | `ReservedFrontendPathRegistry::reserveExact()` / `reservePrefix()` | Frontend provider before fallback routes | Frontend route resolver | Path falls through to page lookup | Assert package route responds and page fallback does not catch it. | | Public route middleware | `FrontendRouteMiddlewareRegistry` | Frontend provider | Public page route | Base middleware order | Assert `all()` order or request side effect. | | Frontend rule condition | `FrontendRuleConditionRegistry::register(...)` | Frontend provider | Runtime rules | Rule never matches | Directly evaluate condition against fixture context. | | Response renderer | `FrontendResponseRendererRegistry::register()` / `registerClass()` | Frontend provider | Runtime response pipeline | Default renderer | Resolve renderer for runtime and assert response class/content. | | Cache invalidation | `CacheInvalidationRegistry::registerDependency(...)` | Frontend/runtime provider | Model observers/cache invalidator | Cache remains until TTL/manual clear | Save fixture model and assert invalidation plan. | | Critical/deferred assets | `CriticalAssetRegistry::registerCritical()` / `registerDeferred()` | Frontend provider | Frontend asset rendering | Asset not emitted | Render page and assert handle/url in expected section. | | Runtime manifest contributors | `FrontendRuntimeManifestContributor::TAG` | Frontend provider | Frontend runtime builder | Manifest lacks package data | Build runtime manifest and assert contribution. | | Asset contributors | `FrontendAssetContributor::TAG` | Frontend provider | Frontend asset manifest builder | Asset absent | Build asset manifest and assert package handle. | ## Installer And Marketplace Runtime | Need | API | Register from | Called by | Safe fallback | Test recipe | | ---------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | -------------------------------------- | --------------------------------- | ----------------------------- | ----------------------------------------------------------------------------- | | Browser install guide patch | `Patch` plus `PatchRegistry::register(...)` | Installer provider `registerPatches()` | Install guide page/action | Patch absent | Probe/apply fixture host file and assert idempotence. | | Installer default packages | `CAPELL_SETUP_DEFAULT_PACKAGES` plus package metadata | Host env/config | Browser installer page data | Package not preselected | Build installer page data and assert default list. | | Extension dashboard widget | `CapellAdmin::registerDashboardWidget($widget, DashboardEnum::Extensions)` or `$registrar->extensionDashboardWidget($widget)` | Admin provider or admin bridge | Extensions dashboard | Widget absent | Register fixture widget and assert it appears in `DashboardEnum::Extensions`. | | Marketplace installed extensions content | `ExtensionsPageExtender::TAG` | Marketplace/provider | Extensions dashboard actions area | No Marketplace alert | Render Extensions page in connected/unconnected states. | | Marketplace theme header action | `ResourceHeaderActionExtender::TAG` | Marketplace/provider | Theme resource header | Action hidden | Render theme resource action list. | | Marketplace activation verification | Container binding `capell.marketplace.activation-verifier` | Marketplace provider | Install/activation flow | Signed activation unavailable | Resolve binding and verify signed fixture payload. | ## Rules - Register in the package that owns the behavior. - Return `null`, an empty array, or no-op output when the package does not support the current context. - Test both the expected contribution and the safe fallback. - Public frontend extensions must pass [public HTML safety](../frontend/public-html-safety.md). ## Next - [Build an extension end to end](build-extension-end-to-end.md) - [Admin extensions](admin-extensions.md) - [Frontend extensions](frontend-extensions.md) - [Extension troubleshooting](extension-troubleshooting.md)