diff --git a/core/lib/Drupal/Core/Annotation/ContextDefinition.php b/core/lib/Drupal/Core/Annotation/ContextDefinition.php
index 987bab95..75fbc9b 100644
--- a/core/lib/Drupal/Core/Annotation/ContextDefinition.php
+++ b/core/lib/Drupal/Core/Annotation/ContextDefinition.php
@@ -100,7 +100,7 @@ public function __construct(array $values) {
     // used in the classes they pass to.
     foreach (['label', 'description'] as $key) {
       // @todo Remove this workaround in https://www.drupal.org/node/2362727.
-      if (isset($values[$key]) && $values[$key] instanceof TranslationWrapper) {
+      if (isset($values[$key]) && $values[$key]->get() instanceof TranslationWrapper) {
         $values[$key] = (string) $values[$key]->get();
       }
       else {
diff --git a/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php b/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
index 19d756c..3766c23 100644
--- a/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
+++ b/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
@@ -61,6 +61,7 @@ protected function addContextAssignmentElement(ContextAwarePluginInterface $plug
           '#options' => $options,
           '#required' => $definition->isRequired(),
           '#default_value' => !empty($assignments[$context_slot]) ? $assignments[$context_slot] : '',
+          '#description' => $definition->getDescription(),
         ];
       }
     }
diff --git a/core/modules/aggregator/src/Plugin/Block/AggregatorFeedBlock.php b/core/modules/aggregator/src/Plugin/Block/AggregatorFeedBlock.php
index 7272d7f..62d1344 100644
--- a/core/modules/aggregator/src/Plugin/Block/AggregatorFeedBlock.php
+++ b/core/modules/aggregator/src/Plugin/Block/AggregatorFeedBlock.php
@@ -24,7 +24,7 @@
  *   admin_label = @Translation("Aggregator feed"),
  *   category = @Translation("Lists (Views)"),
  *   context = {
- *     "feed" = @ContextDefinition("entity:aggregator_feed", label = @Translation("Aggregator feed"))
+ *     "feed" = @ContextDefinition("entity:aggregator_feed", label = @Translation("Aggregator feed"), description = @Translation("Select the feed that should be displayed"))
  *   }
  * )
  *