diff --git a/swh/model/model.py b/swh/model/model.py
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -1513,3 +1513,28 @@
 
     def _compute_hash_from_attributes(self) -> bytes:
         return _compute_hash_from_manifest(git_objects.extid_git_object(self))
+
+
+SWH_MODEL_OBJECT_TYPES = {
+    cls.object_type: cls  # type: ignore
+    for cls in (
+        Person,
+        Timestamp,
+        TimestampWithTimezone,
+        Origin,
+        OriginVisit,
+        OriginVisitStatus,
+        Snapshot,
+        SnapshotBranch,
+        Release,
+        Revision,
+        Directory,
+        DirectoryEntry,
+        Content,
+        SkippedContent,
+        MetadataAuthority,
+        MetadataFetcher,
+        RawExtrinsicMetadata,
+        ExtID,
+    )
+}