diff --git a/src/Extensions/CustomSiteConfig.php b/src/Extensions/CustomSiteConfig.php
index cc15c60..9ca1b20 100644
--- a/src/Extensions/CustomSiteConfig.php
+++ b/src/Extensions/CustomSiteConfig.php
@@ -6,9 +6,12 @@
 use SilverStripe\Forms\TextField;
 use SilverStripe\ORM\DataExtension;
 use SilverStripe\ORM\FieldType\DBField;
+use SilverStripe\SiteConfig\SiteConfig;
 
 /**
  * Adds new global settings.
+ *
+ * @extends DataExtension<SiteConfig>
  */
 class CustomSiteConfig extends DataExtension
 {
diff --git a/src/Extensions/CwpCommentingExtension.php b/src/Extensions/CwpCommentingExtension.php
index b5cad6e..eb763fe 100644
--- a/src/Extensions/CwpCommentingExtension.php
+++ b/src/Extensions/CwpCommentingExtension.php
@@ -2,6 +2,7 @@
 
 namespace CWP\CWP\Extensions;
 
+use SilverStripe\Comments\Controllers\CommentingController;
 use SilverStripe\Control\Email\Email;
 use SilverStripe\Core\Extension;
 use SilverStripe\Forms\Form;
@@ -9,7 +10,7 @@
 /**
  * Customises the comment form to conform to government usability standards
  *
- * {@see CommentingController}
+ * @extends Extension<CommentingController>
  */
 class CwpCommentingExtension extends Extension
 {
diff --git a/src/Extensions/CwpSiteTreeExtension.php b/src/Extensions/CwpSiteTreeExtension.php
index c6e742f..c6ef886 100644
--- a/src/Extensions/CwpSiteTreeExtension.php
+++ b/src/Extensions/CwpSiteTreeExtension.php
@@ -2,11 +2,15 @@
 
 namespace CWP\CWP\Extensions;
 
+use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Forms\CheckboxField;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\LiteralField;
 use SilverStripe\ORM\DataExtension;
 
+/**
+ * @extends DataExtension<SiteTree>
+ */
 class CwpSiteTreeExtension extends DataExtension
 {
     private static $db = array(
diff --git a/src/Extensions/CwpSiteTreeFileExtension.php b/src/Extensions/CwpSiteTreeFileExtension.php
index 3017e7a..112bc58 100644
--- a/src/Extensions/CwpSiteTreeFileExtension.php
+++ b/src/Extensions/CwpSiteTreeFileExtension.php
@@ -2,15 +2,18 @@
 
 namespace CWP\CWP\Extensions;
 
+use SilverStripe\Assets\File;
 use SilverStripe\Core\Convert;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\ReadonlyField;
 use SilverStripe\ORM\DataExtension;
 use SilverStripe\View\Requirements;
 
+/**
+ * @extends DataExtension<File>
+ */
 class CwpSiteTreeFileExtension extends DataExtension
 {
-
     public function updateCMSFields(FieldList $fields)
     {
         Requirements::css('cwp/cwp:css/fieldDescriptionToggle.css');
diff --git a/src/Extensions/CwpWorkflowDefinitionExtension.php b/src/Extensions/CwpWorkflowDefinitionExtension.php
index 565dcb6..944e34e 100644
--- a/src/Extensions/CwpWorkflowDefinitionExtension.php
+++ b/src/Extensions/CwpWorkflowDefinitionExtension.php
@@ -9,6 +9,8 @@
 
 /**
  * Ensures that the default template is created
+ *
+ * @extends DataExtension<WorkflowDefinition>
  */
 class CwpWorkflowDefinitionExtension extends DataExtension
 {
diff --git a/src/Extensions/MaintenanceProxyExtension.php b/src/Extensions/MaintenanceProxyExtension.php
index 9f32772..d538e18 100644
--- a/src/Extensions/MaintenanceProxyExtension.php
+++ b/src/Extensions/MaintenanceProxyExtension.php
@@ -3,6 +3,8 @@
 namespace CWP\CWP\Extension;
 
 use BringYourOwnIdeas\Maintenance\Reports\SiteSummary;
+use BringYourOwnIdeas\Maintenance\Util\ApiLoader;
+use BringYourOwnIdeas\Maintenance\Util\ComposerLoader;
 use SilverStripe\Core\Environment;
 use SilverStripe\Core\Extension;
 
@@ -10,6 +12,8 @@
  * Used to configure proxy settings for bringyourownideas/silverstripe-maintenance and its related modules
  *
  * @see https://www.cwp.govt.nz/developer-docs/en/2/how_tos/external_http_requests_with_proxy
+ *
+ * @extends Extension<ComposerLoader|ApiLoader>
  */
 class MaintenanceProxyExtension extends Extension
 {
diff --git a/src/Extensions/TaxonomyTermExtension.php b/src/Extensions/TaxonomyTermExtension.php
index 3567f38..0b230d2 100644
--- a/src/Extensions/TaxonomyTermExtension.php
+++ b/src/Extensions/TaxonomyTermExtension.php
@@ -6,10 +6,13 @@
 use SilverStripe\ORM\DataExtension;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\GridField\GridFieldAddNewButton;
+use SilverStripe\Taxonomy\TaxonomyTerm;
 
+/**
+ * @extends DataExtension<TaxonomyTerm>
+ */
 class TaxonomyTermExtension extends DataExtension
 {
-
     private static $api_access = true;
 
     private static $belongs_many_many = array(
diff --git a/src/PageTypes/BaseHomePageController.php b/src/PageTypes/BaseHomePageController.php
index 92a637d..c36fdd2 100644
--- a/src/PageTypes/BaseHomePageController.php
+++ b/src/PageTypes/BaseHomePageController.php
@@ -4,6 +4,10 @@
 
 use PageController;
 
+/**
+ * @template T of BaseHomePage
+ * @extends PageController<T>
+ */
 class BaseHomePageController extends PageController
 {
     public function getNewsPage()
diff --git a/src/PageTypes/BasePageController.php b/src/PageTypes/BasePageController.php
index 032c577..3e550e5 100644
--- a/src/PageTypes/BasePageController.php
+++ b/src/PageTypes/BasePageController.php
@@ -5,6 +5,10 @@
 use SilverStripe\CMS\Controllers\ContentController;
 use SilverStripe\ORM\FieldType\DBDatetime;
 
+/**
+ * @template T of BasePage
+ * @extends ContentController<T>
+ */
 class BasePageController extends ContentController
 {
     /**
diff --git a/src/PageTypes/DatedUpdateHolderController.php b/src/PageTypes/DatedUpdateHolderController.php
index d721ffa..19bf1c1 100644
--- a/src/PageTypes/DatedUpdateHolderController.php
+++ b/src/PageTypes/DatedUpdateHolderController.php
@@ -32,6 +32,9 @@
  *
  * When the user clicks on a month, pagination will be reset, but tags retained. Pagination retains all other
  * parameters.
+ *
+ * @template T of DatedUpdateHolder
+ * @extends PageController<T>
  */
 class DatedUpdateHolderController extends PageController
 {
diff --git a/src/PageTypes/EventHolderController.php b/src/PageTypes/EventHolderController.php
index 7bf676c..904af16 100644
--- a/src/PageTypes/EventHolderController.php
+++ b/src/PageTypes/EventHolderController.php
@@ -16,6 +16,8 @@
  *
  * When the user clicks on a month, pagination will be reset, but tags retained. Pagination retains all other
  * parameters.
+ *
+ * @extends DatedUpdateHolderController<EventHolder>
  */
 class EventHolderController extends DatedUpdateHolderController
 {
diff --git a/src/PageTypes/EventPageController.php b/src/PageTypes/EventPageController.php
index 6d5eab6..d24c89b 100644
--- a/src/PageTypes/EventPageController.php
+++ b/src/PageTypes/EventPageController.php
@@ -4,6 +4,9 @@
 
 use PageController;
 
+/**
+ * @extends PageController<EventPage>
+ */
 class EventPageController extends PageController
 {
 
diff --git a/src/PageTypes/NewsHolderController.php b/src/PageTypes/NewsHolderController.php
index 261ef6d..a9fed0d 100644
--- a/src/PageTypes/NewsHolderController.php
+++ b/src/PageTypes/NewsHolderController.php
@@ -5,6 +5,9 @@
 use CWP\Core\Feed\CwpAtomFeed;
 use SilverStripe\Control\RSS\RSSFeed;
 
+/**
+ * @extends DatedUpdateHolderController<NewsHolder>
+ */
 class NewsHolderController extends DatedUpdateHolderController
 {
     private static $allowed_actions = [
diff --git a/src/PageTypes/SitemapPageController.php b/src/PageTypes/SitemapPageController.php
index 5e2b310..a947bf2 100644
--- a/src/PageTypes/SitemapPageController.php
+++ b/src/PageTypes/SitemapPageController.php
@@ -5,6 +5,9 @@
 use PageController;
 use SilverStripe\CMS\Model\SiteTree;
 
+/**
+ * @extends PageController<SitemapPage>
+ */
 class SitemapPageController extends PageController
 {
     private static $allowed_actions = [