diff --git a/src/Vervis/Actor/Person/Client.hs b/src/Vervis/Actor/Person/Client.hs
index ffa905a..c3e663f 100644
--- a/src/Vervis/Actor/Person/Client.hs
+++ b/src/Vervis/Actor/Person/Client.hs
@@ -507,6 +507,9 @@ clientInvite now personMeID (ClientMsg maybeCap localRecips remoteRecips fwdHost
                 manager <- asksEnv envHttpManager
                 coll <- ExceptT $ liftIO $ first T.pack <$> AP.fetchAPID manager AP.collectionId h luColl
                 lu <- fromMaybeE (AP.collectionContext (coll :: AP.Collection FedURI URIMode)) "Remote topic collabs has no 'context'"
+                AP.ResourceWithCollections _ mluCollabs _ <- ExceptT $ liftIO $ first (T.pack . show) <$> AP.fetchRWC manager h lu
+                unless (mluCollabs == Just luColl) $
+                    throwE "Invite target isn't a collabs list"
 
                 instanceID <-
                     lift $ withDB $ either entityKey id <$> insertBy' (Instance h)
diff --git a/src/Vervis/Client.hs b/src/Vervis/Client.hs
index 14aaa5c..9d6c47a 100644
--- a/src/Vervis/Client.hs
+++ b/src/Vervis/Client.hs
@@ -1011,6 +1011,9 @@ invite personID uRecipient uResourceCollabs role = do
                 manager <- asksSite appHttpManager
                 coll <- ExceptT $ liftIO $ first T.pack <$> AP.fetchAPID manager AP.collectionId h luColl
                 lu <- fromMaybeE (AP.collectionContext (coll :: AP.Collection FedURI URIMode)) "Remote topic collabs has no 'context'"
+                AP.ResourceWithCollections _ mluCollabs _ <- ExceptT $ liftIO $ first (T.pack . show) <$> AP.fetchRWC manager h lu
+                unless (mluCollabs == Just luColl) $
+                    throwE "Invite target isn't a collabs list"
                 return $ ObjURI h lu
             )
             resource
@@ -1104,6 +1107,9 @@ remove personID uRecipient uResourceCollabs = do
                 manager <- asksSite appHttpManager
                 coll <- ExceptT $ liftIO $ first T.pack <$> AP.fetchAPID manager AP.collectionId h luColl
                 lu <- fromMaybeE (AP.collectionContext (coll :: AP.Collection FedURI URIMode)) "Remote topic collabs has no 'context'"
+                AP.ResourceWithCollections _ mluCollabs _ <- ExceptT $ liftIO $ first (T.pack . show) <$> AP.fetchRWC manager h lu
+                unless (mluCollabs == Just luColl) $
+                    throwE "Remove origin isn't a collabs list"
                 return $ ObjURI h lu
             )
             resource
diff --git a/src/Web/ActivityPub.hs b/src/Web/ActivityPub.hs
index e1b8131..7488079 100644
--- a/src/Web/ActivityPub.hs
+++ b/src/Web/ActivityPub.hs
@@ -49,6 +49,7 @@ module Web.ActivityPub
     , CollectionPage (..)
     , Recipient (..)
     , Resource (..)
+    , ResourceWithCollections (..)
     , Project (..)
 
       -- * Content objects
@@ -125,6 +126,7 @@ module Web.ActivityPub
     , fetchTip
     , fetchRecipient
     , fetchResource
+    , fetchRWC
     , keyListedByActor
     , fetchUnknownKey
     , fetchKnownPersonalKey
@@ -847,6 +849,24 @@ instance ActivityPub Resource where
         =  "id"        .= ObjURI h luId
         <> "managedBy" .= ObjURI h luManager
 
+data ResourceWithCollections u = ResourceWithCollections
+    { rwcResource   :: Resource u
+    , rwcCollabs    :: Maybe LocalURI
+    , rwcComponents :: Maybe LocalURI
+    }
+
+instance ActivityPub ResourceWithCollections where
+    jsonldContext _ = [as2Context, secContext, forgeContext]
+    parseObject o = do
+        (h, r) <- parseObject o
+        fmap (h,) $ ResourceWithCollections r
+            <$> withAuthorityMaybeO h (o .:? "collaborators")
+            <*> withAuthorityMaybeO h (o .:? "components")
+    toSeries h (ResourceWithCollections r collabs comps)
+        =  toSeries h r
+        <> "collaborators" .=? (ObjURI h <$> collabs)
+        <> "components"    .=? (ObjURI h <$> comps)
+
 data Project u = Project
     { projectActor      :: Actor u
     , projectTracker    :: Maybe (ObjURI u)
@@ -2602,6 +2622,12 @@ fetchResource m = fetchAPID' m getId
     getId (ResourceActor a)      = actorId $ actorLocal a
     getId (ResourceChild luId _) = luId
 
+fetchRWC :: UriMode u => Manager -> Authority u -> LocalURI -> IO (Either (Maybe APGetError) (ResourceWithCollections u))
+fetchRWC m = fetchAPID' m (getId . rwcResource)
+    where
+    getId (ResourceActor a)      = actorId $ actorLocal a
+    getId (ResourceChild luId _) = luId
+
 fetchAPID :: (MonadIO m, UriMode u, ActivityPub a) => Manager -> (a u -> LocalURI) -> Authority u -> LocalURI -> m (Either String (a u))
 fetchAPID m getId h lu = first showError <$> fetchAPID' m getId h lu
     where