1 files changed, 5 insertions, 1 deletions
diff --git a/app/serializers/activitypub/undo_block_serializer.rb b/app/serializers/activitypub/undo_block_serializer.rb
index f71faa729..2f43d8402 100644
--- a/app/serializers/activitypub/undo_block_serializer.rb
+++ b/app/serializers/activitypub/undo_block_serializer.rb
@@ -1,10 +1,14 @@
 # frozen_string_literal: true
 
 class ActivityPub::UndoBlockSerializer < ActiveModel::Serializer
-  attributes :type, :actor
+  attributes :id, :type, :actor
 
   has_one :object, serializer: ActivityPub::BlockSerializer
 
+  def id
+    [ActivityPub::TagManager.instance.uri_for(object.account), '#blocks/', object.id, '/undo'].join
+  end
+
   def type
     'Undo'
   end