diff --git a/openviking/server/routers/system.py b/openviking/server/routers/system.py
index 0ec16977..cab9acc9 100644
--- a/openviking/server/routers/system.py
+++ b/openviking/server/routers/system.py
@@ -30,7 +30,7 @@ async def system_status(
         status="ok",
         result={
             "initialized": service._initialized,
-            "user": service.user,
+            "user": service.user._user_id,
         },
     )
 
diff --git a/openviking/session/memory_extractor.py b/openviking/session/memory_extractor.py
index 14fc7a21..32379387 100644
--- a/openviking/session/memory_extractor.py
+++ b/openviking/session/memory_extractor.py
@@ -18,6 +18,8 @@
 from openviking.storage.viking_fs import get_viking_fs
 from openviking.utils import get_logger
 from openviking.utils.config import get_openviking_config
+from openviking.session.user_id import UserIdentifier
+
 
 logger = get_logger(__name__)
 
@@ -67,11 +69,11 @@ def __init__(self):
     async def extract(
         self,
         context: dict,
-        user: str,
+        user: UserIdentifier,
         session_id: str,
     ) -> List[CandidateMemory]:
         """Extract memory candidates from messages."""
-        user = user or "default"
+        user = user
         vlm = get_openviking_config().vlm
         if not vlm or not vlm.is_available():
             logger.warning("LLM not available, skipping memory extraction")
@@ -91,7 +93,7 @@ async def extract(
             {
                 "summary": "",
                 "recent_messages": formatted_messages,
-                "user": user,
+                "user": user._user_id,
                 "feedback": "",
             },
         )
diff --git a/tests/integration/test_full_workflow.py b/tests/integration/test_full_workflow.py
index e60db321..aa8b71a2 100644
--- a/tests/integration/test_full_workflow.py
+++ b/tests/integration/test_full_workflow.py
@@ -3,6 +3,7 @@
 
 """Full workflow integration tests"""
 
+import shutil
 from pathlib import Path
 
 import pytest_asyncio
@@ -17,6 +18,10 @@ async def integration_client(test_data_dir: Path):
     """Integration test client"""
     await AsyncOpenViking.reset()
 
+    # Clean data directory to avoid AGFS "directory already exists" errors
+    shutil.rmtree(test_data_dir, ignore_errors=True)
+    test_data_dir.mkdir(parents=True, exist_ok=True)
+
     client = AsyncOpenViking(path=str(test_data_dir), user=UserIdentifier.the_default_user("integration_test_user"))
     await client.initialize()
 
@@ -149,6 +154,7 @@ async def test_export_import_roundtrip(
             path=str(sample_markdown_file),
             reason="Export test",
         )
+        print(result)
         original_uri = result["root_uri"]
 
         # 2. Read original content