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 if you are still deciding.

Registration uses two complementary mechanisms: contract tags for focused contributors, and AdminBridgeRegistrar for grouped admin integration. AdminBridgeRegistry is the internal read side, not a package-authoring write path. See Package provider conventions before adding provider wiring or a new registry.

Machine-readable stability and ownership are defined by the extension surface catalogue. Use its stable IDs in compatibility decisions and package contract failures.

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::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	Provider `surface()` or `AdminBridgeRegistrar`	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 and any `viewDataResolver` returns explicit view variables.
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 Filament widget	`CapellAdmin::registerDashboardFilamentWidget(...)`	Admin provider or bridge	Dashboard Filament 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.
Role workspace tool	`AdminBridgeRegistrar::workspace(AdminWorkspaceItemData $item)`	Admin bridge or runtime/admin provider	Header workspace switcher	Item hidden	Register a translated label, a typed Page/Resource URL with `isAbsolute: false`, and the required permission; assert the bridge definition and visible filtered result.
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 resource contributions	`UserResourceBridge::TAG`	Register through admin bridge	User resource bridge resolver	Base user resource only	Assert context, lifecycle, and visible contribution behavior.
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.
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` or `AdminBridgeRegistrar::extensionsPageExtender()`	Admin bridge or provider	Installed Extensions page	No package alert/content	Render Extensions page and assert package section.
Extensions page actions	`AdminBridgeRegistrar::extensionsPageHeaderAction()`, `extensionsPageHeaderActionGroupAction()`, or `extensionsPageTableAction()`	Admin bridge	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 resource links/display/revert	`CapellAdmin::registerActivityResourceLink(...)`, `ActivityChangeSetBuilder::TAG`, `ActivityRevertHandler::TAG`	Admin provider	Activity table/revert actions	Default activity behavior	Run activity link builder/revert fixture.
Site Health report	`SiteHealthReportExtender::TAG`	Admin provider	Site Health action/page	Report section absent	Build Site Health report and assert section.

Workspace tool URLs are a discovery-only contract and must resolve to root-relative, same-origin paths. Use Page::getUrl(..., isAbsolute: false), Resource::getUrl(..., isAbsolute: false), or route(..., absolute: false) when those typed targets exist. The registry rejects absolute, protocol-relative, control-character, and backslash-containing destinations; direct Page/Resource policies remain authoritative.

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	`LayoutWidgetRegistry::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.
Runtime frontend assets	`FrontendResourceRegistry` groups / `FrontendResourceContributor::TAG`	Frontend provider	Frontend resource-plan builder	Asset not emitted	Build resource plan and assert resource handle/url.
Runtime manifest contributors	`FrontendRuntimeManifestContributor::TAG`	Frontend provider	Frontend runtime builder	Manifest lacks package data	Build runtime manifest and assert contribution.
Resource contributors	`FrontendResourceContributor::TAG`	Frontend provider	Frontend resource-plan builder	Asset absent	Build resource plan 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 Filament widget	`CapellAdmin::registerDashboardFilamentWidget($widget, DashboardEnum::Extensions)` or `$registrar->extensionDashboardFilamentWidget($widget)`	Admin provider or admin bridge	Extensions dashboard	Widget absent	Register fixture widget and assert it appears in `DashboardEnum::Extensions`.
Marketplace installed extensions content	`AdminBridgeRegistrar::extensionsPageExtender()`	Marketplace admin bridge	Extensions dashboard actions area	No Marketplace alert	Render Extensions page in connected/unconnected states.
Marketplace theme header action	`AdminBridgeRegistrar::resourceHeaderActionExtender()`	Marketplace admin bridge	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.

Declared Contributions

Alongside the runtime extension points above, a package declares what it contributes in its capell.json contributes[] array. Each entry names a type and a class, and the class must implement the contract that type maps to.

These contracts are marker interfaces. They declare no registration methods — the only method comes from the base contract, Capell\Core\Contracts\Extensions\ExtensionContribution:

public static function compatibleCapellApiVersion(): string;

The marker’s job is validation and traceability, not wiring. You still register runtime behaviour through the extension points documented above; the declaration is what lets manifest audits know the surface exists.

namespace Vendor\Example\Routes;

use Capell\Core\Contracts\Extensions\RegistersExtensionRoute;

final class ExampleRoutes implements RegistersExtensionRoute
{
    public static function compatibleCapellApiVersion(): string
    {
        return '^1.0';
    }
}

"contributes": [
  { "type": "route", "class": "Vendor\\Example\\Routes\\ExampleRoutes" },
  { "type": "content-widget", "key": "vendor.hero", "class": "Vendor\\Example\\Widgets\\HeroWidget" }
]

`type`	Contract (in `Capell\Core\Contracts\Extensions`)
`admin-resource`	`RegistersExtensionAdminResource`
`section`	`RegistersExtensionSection`
`page-type`, `page-variation`	`RegistersExtensionPageType`
`dashboard-widget`, `overview-stat`	`RegistersExtensionFilamentWidget`
`permission`	`RegistersExtensionPermission`
`route`	`RegistersExtensionRoute`
`setting`	`RegistersExtensionSetting`
`frontend-component`	`RegistersExtensionFrontendComponent`
`content-widget`	`RegistersExtensionContentWidget`
`render-hook`	`RegistersExtensionRenderHook`
`asset`	`RegistersExtensionAsset`
`migration`	`RunsExtensionMigration`
`scheduled-job`	`RunsScheduledExtensionJob`
`health-check`	`ChecksExtensionHealth`
`content-graph`	`ContentGraphExtractor`
`workflow-attention`	`ContributesWorkflowAttention`

Validation rejects a manifest when the class sits outside the package’s own PSR-4 namespace, spoofs a Capell namespace, or does not implement the mapped contract. A content-widget also needs a key matching ^[a-z0-9][a-z0-9-]*\.[a-z0-9][a-z0-9.-]*$, prefixed with your vendor and unique within the manifest. Content widgets were added in API 1.1, so declare ^1.1 for those.

Verify with php artisan capell:extension-audit, explore with php artisan capell:extension-playground, and assert in tests with Capell\Core\Testing\ExtensionTestHarness::assertContributionRegistered().

Frontend Route Middleware

An application adding its own frontend route must apply Capell’s middleware stack, or there is no resolved site, page, or language context. Take the canonical list from Capell\Frontend\Support\Routing\FrontendRouteMiddlewareRegistry::all() rather than hand-listing aliases — it is the source of truth and supports prepend(), append(), insertBefore(), and insertAfter().

Alias	Purpose
`frontend.resolve`	Bootstraps the frontend kernel and resolves site, page, and language. Required.
`frontend.maintenance`	Serves cached maintenance and lockdown pages. Lockdown ignores all bypasses.
`frontend.anonymous_cacheable_render`	Nulls the user resolver so an authenticated response cannot poison a shared HTML cache entry
`frontend.rendering_strategy`	Adds an `X-Rendering-Strategy` diagnostic header. Optional, not in the default stack.
`frontend.etag`, `frontend.asset-optimization`	ETag and asset optimisation. Optional, not in the default stack.

Registering Public Components

capell-frontend.blade_components and capell-frontend.livewire_components are flat name => class maps and the supported way for a theme or app to register or override a public component. Entries whose value is not a string — or, for Livewire, not a Livewire\Component subclass — are silently ignored.

Packages should contribute through Capell\Frontend\Contracts\FrontendComponentContributor instead, tagged with that interface’s TAG constant. Contributor entries take precedence over config.

Deprecated Downstream Contract Aliases

Three contracts exist in both Core and a downstream package. In each case Core owns the definition and the downstream copy is a deprecated, empty extending alias. Existing implementations of a downstream alias remain valid implementations of the Core contract, but new code must import and bind the Core contract. Migrate existing imports before the downstream aliases are removed in the next major release.

Deprecated alias	Replace with	Note
`Capell\Frontend\Contracts\RedirectResolver`	`Capell\Core\Contracts\RedirectResolver`	Public page resolution reads the Core contract. Binding only the deprecated alias does not change redirect behaviour.
`Capell\Admin\Contracts\SettingsSchemaContract`	`Capell\Core\Contracts\SettingsSchemaContract`	Settings discovery accepts the Core contract.
`Capell\Admin\Contracts\Themes\ThemePreviewRendererInterface`	`Capell\Core\Contracts\Themes\ThemePreviewRendererInterface`	The frontend renderer is bound to the Core contract.

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.
The HTML sanitizer is rebuilt from capell-frontend.html_content_allowed_attributes for each invocation. Site-scoped configuration resolved before rendering therefore remains isolated between requests, including in long-lived workers.