diff --git a/bookwyrm/activitypub/__init__.py b/bookwyrm/activitypub/__init__.py
index 201e8042d..510f1f3f4 100644
--- a/bookwyrm/activitypub/__init__.py
+++ b/bookwyrm/activitypub/__init__.py
@@ -16,7 +16,7 @@ from .response import ActivitypubResponse
 from .book import Edition, Work, Author
 from .verbs import Create, Delete, Undo, Update
 from .verbs import Follow, Accept, Reject, Block
-from .verbs import Add, AddBook, Remove
+from .verbs import Add, AddBook, AddListItem, Remove
 
 # this creates a list of all the Activity types that we can serialize,
 # so when an Activity comes in from outside, we can check if it's known
diff --git a/bookwyrm/activitypub/base_activity.py b/bookwyrm/activitypub/base_activity.py
index 4bbb5e9f3..5f35f1d7e 100644
--- a/bookwyrm/activitypub/base_activity.py
+++ b/bookwyrm/activitypub/base_activity.py
@@ -65,6 +65,13 @@ class ActivityObject:
 
     def to_model(self, model, instance=None, save=True):
         ''' convert from an activity to a model instance '''
+        if self.type != model.activity_serializer.type:
+            raise ActivitySerializerError(
+                'Wrong activity type "%s" for activity of type "%s"' % \
+                        (model.activity_serializer.type,
+                         self.type)
+            )
+
         if not isinstance(self, model.activity_serializer):
             raise ActivitySerializerError(
                 'Wrong activity type "%s" for model "%s" (expects "%s")' % \
diff --git a/bookwyrm/activitypub/verbs.py b/bookwyrm/activitypub/verbs.py
index 5502ced01..190cd7395 100644
--- a/bookwyrm/activitypub/verbs.py
+++ b/bookwyrm/activitypub/verbs.py
@@ -70,17 +70,26 @@ class Reject(Verb):
 @dataclass(init=False)
 class Add(Verb):
     '''Add activity '''
-    target: ActivityObject
+    target: str
+    object: ActivityObject
     type: str = 'Add'
 
 
 @dataclass(init=False)
-class AddBook(Verb):
+class AddBook(Add):
     '''Add activity that's aware of the book obj '''
-    target: Edition
+    object: Edition
     type: str = 'Add'
 
 
+@dataclass(init=False)
+class AddListItem(AddBook):
+    '''Add activity that's aware of the book obj '''
+    notes: str = None
+    order: int = 0
+    approved: bool = True
+
+
 @dataclass(init=False)
 class Remove(Verb):
     '''Remove activity '''
diff --git a/bookwyrm/incoming.py b/bookwyrm/incoming.py
index a88a748e4..202bf806b 100644
--- a/bookwyrm/incoming.py
+++ b/bookwyrm/incoming.py
@@ -319,8 +319,19 @@ def handle_add(activity):
     #this is janky as heck but I haven't thought of a better solution
     try:
         activitypub.AddBook(**activity).to_model(models.ShelfBook)
+        return
     except activitypub.ActivitySerializerError:
-        activitypub.AddBook(**activity).to_model(models.Tag)
+        pass
+    try:
+        activitypub.AddListItem(**activity).to_model(models.ListItem)
+        return
+    except activitypub.ActivitySerializerError:
+        pass
+    try:
+        activitypub.AddBook(**activity).to_model(models.UserTag)
+        return
+    except activitypub.ActivitySerializerError:
+        pass
 
 
 @app.task
diff --git a/bookwyrm/models/list.py b/bookwyrm/models/list.py
index db8c1af6e..ef48ed956 100644
--- a/bookwyrm/models/list.py
+++ b/bookwyrm/models/list.py
@@ -68,7 +68,7 @@ class ListItem(CollectionItemMixin, BookWyrmModel):
     order = fields.IntegerField(blank=True, null=True)
     endorsement = models.ManyToManyField('User', related_name='endorsers')
 
-    activity_serializer = activitypub.AddBook
+    activity_serializer = activitypub.AddListItem
     object_field = 'book'
     collection_field = 'book_list'