diff --git a/app/routers/auth.py b/app/routers/auth.py
index ee569f2..315307c 100644
--- a/app/routers/auth.py
+++ b/app/routers/auth.py
@@ -142,7 +142,7 @@ async def callback(request: Request):
     # Map OAuth response to artdag UserContext
     display_name = data.get("display_name", "")
     username = data.get("username", "")
-    actor_id = f"@{display_name}" if display_name else f"@{username}"
+    actor_id = f"@{username}"
 
     user = UserContext(username=username, actor_id=actor_id)