diff --git a/memory_system_api/clients.py b/memory_system_api/clients.py
index 4ee0232..b84e61c 100644
--- a/memory_system_api/clients.py
+++ b/memory_system_api/clients.py
@@ -1,6 +1,7 @@
 """Async clients for OpenViking and EverOS used by the lightweight API."""
 from __future__ import annotations
 
+from dataclasses import dataclass
 from datetime import datetime, timezone
 from typing import Any
 
@@ -10,6 +11,13 @@ from .config import get_config
 from .store import OpenVikingUserKeyStore
 
 
+@dataclass(frozen=True)
+class OpenVikingCredential:
+    api_key: str
+    account_id: str | None = None
+    user_id: str | None = None
+
+
 class OpenVikingMemorySystemClient:
     def __init__(self, store: OpenVikingUserKeyStore | None = None) -> None:
         config = get_config()
@@ -25,35 +33,42 @@ class OpenVikingMemorySystemClient:
             response.raise_for_status()
             return response.json()
 
-    async def ensure_user(self, user_id: str) -> str:
+    async def ensure_user(self, user_id: str) -> OpenVikingCredential:
         existing = self.store.get_user_key(user_id)
         if existing:
-            return existing
+            return OpenVikingCredential(api_key=existing)
 
         async with self._client(self.root_key) as client:
             response = await client.post(
                 "/api/v1/admin/accounts",
                 json={"account_id": user_id, "admin_user_id": user_id},
             )
+            if response.status_code == 409:
+                return self.root_credential(user_id)
             response.raise_for_status()
             data = response.json()
 
         user_key = self._extract_user_key(data)
         if not user_key:
-            raise RuntimeError("OpenViking did not return user_key")
+            return self.root_credential(user_id)
         self.store.save_user_key(user_id, user_key)
-        return user_key
+        return OpenVikingCredential(api_key=user_key)
 
-    async def ensure_session(self, user_key: str, session_id: str) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    def root_credential(self, user_id: str) -> OpenVikingCredential:
+        return OpenVikingCredential(api_key=self.root_key, account_id=user_id, user_id=user_id)
+
+    async def ensure_session(self, credential: OpenVikingCredential | str, session_id: str) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.post("/api/v1/sessions", json={"session_id": session_id})
             if response.status_code in {409, 422}:
                 return {"session_id": session_id, "status": "exists"}
             response.raise_for_status()
             return response.json()
 
-    async def append_message(self, user_key: str, session_id: str, role: str, content: str) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    async def append_message(
+        self, credential: OpenVikingCredential | str, session_id: str, role: str, content: str
+    ) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.post(
                 f"/api/v1/sessions/{session_id}/messages",
                 json={"role": role, "content": content},
@@ -61,26 +76,28 @@ class OpenVikingMemorySystemClient:
             response.raise_for_status()
             return response.json()
 
-    async def commit_session(self, user_key: str, session_id: str) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    async def commit_session(self, credential: OpenVikingCredential | str, session_id: str) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.post(f"/api/v1/sessions/{session_id}/commit")
             response.raise_for_status()
             return response.json()
 
-    async def extract_session(self, user_key: str, session_id: str) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    async def extract_session(self, credential: OpenVikingCredential | str, session_id: str) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.post(f"/api/v1/sessions/{session_id}/extract")
             response.raise_for_status()
             return response.json()
 
-    async def get_task(self, user_key: str, task_id: str) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    async def get_task(self, credential: OpenVikingCredential | str, task_id: str) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.get(f"/api/v1/tasks/{task_id}")
             response.raise_for_status()
             return response.json()
 
-    async def find(self, user_key: str, user_id: str, query: str, limit: int) -> dict[str, Any]:
-        async with self._client(user_key) as client:
+    async def find(
+        self, credential: OpenVikingCredential | str, user_id: str, query: str, limit: int
+    ) -> dict[str, Any]:
+        async with self._credential_client(credential) as client:
             response = await client.post(
                 "/api/v1/search/find",
                 json={
@@ -92,19 +109,34 @@ class OpenVikingMemorySystemClient:
             response.raise_for_status()
             return response.json()
 
-    async def search(self, user_key: str, session_id: str | None, query: str, limit: int) -> dict[str, Any]:
+    async def search(
+        self, credential: OpenVikingCredential | str, session_id: str | None, query: str, limit: int
+    ) -> dict[str, Any]:
         payload: dict[str, Any] = {"query": query, "limit": limit}
         if session_id:
             payload["session_id"] = session_id
-        async with self._client(user_key) as client:
+        async with self._credential_client(credential) as client:
             response = await client.post("/api/v1/search/search", json=payload)
             response.raise_for_status()
             return response.json()
 
-    def _client(self, api_key: str) -> httpx.AsyncClient:
+    def _credential_client(self, credential: OpenVikingCredential | str) -> httpx.AsyncClient:
+        if isinstance(credential, str):
+            return self._client(credential)
+        headers = {}
+        if credential.account_id:
+            headers["X-OpenViking-Account"] = credential.account_id
+        if credential.user_id:
+            headers["X-OpenViking-User"] = credential.user_id
+        return self._client(credential.api_key, headers)
+
+    def _client(self, api_key: str, extra_headers: dict[str, str] | None = None) -> httpx.AsyncClient:
+        headers = {"X-API-Key": api_key, "Content-Type": "application/json"}
+        if extra_headers:
+            headers.update(extra_headers)
         return httpx.AsyncClient(
             base_url=self.base_url,
-            headers={"X-API-Key": api_key, "Content-Type": "application/json"},
+            headers=headers,
             timeout=self.timeout,
             verify=self.verify_ssl,
         )
diff --git a/memory_system_api/config.py b/memory_system_api/config.py
index 6b74a51..8976863 100644
--- a/memory_system_api/config.py
+++ b/memory_system_api/config.py
@@ -25,7 +25,7 @@ class OpenVikingConfig(BaseModel):
 class EverOSConfig(BaseModel):
     url: str = "http://127.0.0.1:1995"
     api_key: str = ""
-    timeout: int = 30
+    timeout: int = 180
     verify_ssl: bool = True
     health_path: str = "/health"
 
diff --git a/memory_system_api/service.py b/memory_system_api/service.py
index 053fcfb..6dc7093 100644
--- a/memory_system_api/service.py
+++ b/memory_system_api/service.py
@@ -27,16 +27,14 @@ class MemorySystemService:
         if not messages:
             raise ValueError("at least one message is required")
 
-        user_key = await self.openviking.ensure_user(request.user_id)
-        await self.openviking.ensure_session(user_key, request.session_id)
-
-        print("user_key:", user_key)  # Debugging line to check the user_key value
+        credential = await self.openviking.ensure_user(request.user_id)
+        await self.openviking.ensure_session(credential, request.session_id)
 
         async def write_openviking() -> list[dict[str, Any]]:
             results = []
             for message in messages:
                 results.append(
-                    await self.openviking.append_message(user_key, request.session_id, message["role"], message["content"])
+                    await self.openviking.append_message(credential, request.session_id, message["role"], message["content"])
                 )
             return results
 
@@ -97,6 +95,7 @@ class MemorySystemService:
             )
 
         backends = await self._run_backends(openviking=search_openviking, everos=search_everos)
+        backends = self._remove_vectors_from_backends(backends)
         items = self._merge_search_items(backends)
         return SearchResponse(status=self._aggregate_status(backends), items=items[: request.limit], backends=backends)
 
@@ -126,7 +125,9 @@ class MemorySystemService:
         try:
             return BackendStatus(status="success", result=await call())
         except Exception as exc:  # noqa: BLE001
-            return BackendStatus(status="failed", error=str(exc))
+            message = str(exc)
+            error = f"{type(exc).__name__}: {message}" if message else type(exc).__name__
+            return BackendStatus(status="failed", error=error)
 
     def _aggregate_status(self, backends: dict[str, BackendStatus]) -> str:
         statuses = {backend.status for backend in backends.values()}
@@ -163,3 +164,16 @@ class MemorySystemService:
         if "source_backend" in item:
             return item
         return {"source_backend": backend_name, **item}
+
+    def _remove_vectors_from_backends(self, backends: dict[str, BackendStatus]) -> dict[str, BackendStatus]:
+        return {
+            name: backend.model_copy(update={"result": self._remove_vectors(backend.result)})
+            for name, backend in backends.items()
+        }
+
+    def _remove_vectors(self, value: Any) -> Any:
+        if isinstance(value, dict):
+            return {key: self._remove_vectors(item) for key, item in value.items() if key != "vector"}
+        if isinstance(value, list):
+            return [self._remove_vectors(item) for item in value]
+        return value
diff --git a/tests/test_memory_system_clients.py b/tests/test_memory_system_clients.py
index a4f2f33..e933b2f 100644
--- a/tests/test_memory_system_clients.py
+++ b/tests/test_memory_system_clients.py
@@ -1,4 +1,96 @@
-from memory_system_api.clients import EverOSMemorySystemClient
+import asyncio
+
+from memory_system_api.clients import EverOSMemorySystemClient, OpenVikingMemorySystemClient
+
+
+class FakeStore:
+    def __init__(self):
+        self.saved = {}
+
+    def get_user_key(self, user_id: str) -> str | None:
+        return self.saved.get(user_id)
+
+    def save_user_key(self, user_id: str, user_key: str) -> None:
+        self.saved[user_id] = user_key
+
+
+class FakeResponse:
+    def __init__(self, status_code: int, data: dict):
+        self.status_code = status_code
+        self._data = data
+
+    def json(self) -> dict:
+        return self._data
+
+    def raise_for_status(self) -> None:
+        if self.status_code >= 400:
+            raise AssertionError(f"unexpected status {self.status_code}")
+
+
+class FakeAsyncClient:
+    def __init__(self, calls: list, responses: list[FakeResponse], api_key: str, headers: dict):
+        self.calls = calls
+        self.responses = responses
+        self.api_key = api_key
+        self.headers = headers
+
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc, tb):
+        return False
+
+    async def post(self, path: str, json: dict | None = None) -> FakeResponse:
+        self.calls.append(("post", self.api_key, self.headers, path, json))
+        return self.responses.pop(0)
+
+
+def test_openviking_uses_root_identity_when_account_already_exists():
+    store = FakeStore()
+    client = OpenVikingMemorySystemClient(store=store)
+    client.root_key = "root-key"
+    calls = []
+    responses = [FakeResponse(409, {"status": "error", "error": {"code": "CONFLICT"}})]
+    client._client = lambda api_key, extra_headers=None: FakeAsyncClient(  # type: ignore[method-assign]
+        calls,
+        responses,
+        api_key,
+        extra_headers or {},
+    )
+
+    credential = asyncio.run(client.ensure_user("tom"))
+
+    assert credential.api_key == "root-key"
+    assert credential.account_id == "tom"
+    assert credential.user_id == "tom"
+    assert store.saved == {}
+
+
+def test_openviking_root_identity_headers_are_sent_for_session_create():
+    client = OpenVikingMemorySystemClient(store=FakeStore())
+    client.root_key = "root-key"
+    calls = []
+    responses = [FakeResponse(200, {"status": "ok", "result": {"session_id": "sess-2"}})]
+    client._client = lambda api_key, extra_headers=None: FakeAsyncClient(  # type: ignore[method-assign]
+        calls,
+        responses,
+        api_key,
+        extra_headers or {},
+    )
+    credential = client.root_credential("tom")
+
+    result = asyncio.run(client.ensure_session(credential, "sess-2"))
+
+    assert result == {"status": "ok", "result": {"session_id": "sess-2"}}
+    assert calls == [
+        (
+            "post",
+            "root-key",
+            {"X-OpenViking-Account": "tom", "X-OpenViking-User": "tom"},
+            "/api/v1/sessions",
+            {"session_id": "sess-2"},
+        )
+    ]
 
 
 def test_everos_assistant_payload_does_not_use_user_id_as_sender():
diff --git a/tests/test_memory_system_service.py b/tests/test_memory_system_service.py
index ece25b4..b42dd6b 100644
--- a/tests/test_memory_system_service.py
+++ b/tests/test_memory_system_service.py
@@ -51,6 +51,62 @@ class FakeEverOS:
         return {"items": [{"source": f"everos-{method}"}]}
 
 
+class FakeEverOSWithVector(FakeEverOS):
+    async def search(self, user_id: str, session_id: str | None, query: str, method: str, limit: int) -> dict:
+        self.calls.append(("search", user_id, session_id, query, method, limit))
+        return {
+            "data": {
+                "episodes": [{"id": "episode-1", "vector": [0.1, 0.2]}],
+                "original_data": {
+                    "episodes": {
+                        "episode-1": {
+                            "summary": "喜欢拿铁",
+                            "vector": [0.1, 0.2],
+                            "nested": {"vector": [0.3]},
+                        }
+                    }
+                },
+            }
+        }
+
+
+def test_capture_includes_exception_type_when_message_is_empty():
+    service = MemorySystemService(openviking=FakeOpenViking(), everos=FakeEverOS())
+
+    class EmptyError(Exception):
+        pass
+
+    async def fail():
+        raise EmptyError()
+
+    response = asyncio.run(service._capture(fail))
+
+    assert response.status == "failed"
+    assert response.error == "EmptyError"
+
+
+def test_search_removes_vectors_from_items_and_backend_results():
+    service = MemorySystemService(openviking=FakeOpenViking(), everos=FakeEverOSWithVector())
+
+    response = asyncio.run(service.search(
+        SearchRequest(user_id="tom", session_id="sess-1", query="咖啡偏好", use_llm=False, limit=5)
+    ))
+
+    assert response.items == [
+        {"source_backend": "openviking", "source": "openviking-find"},
+        {"source_backend": "everos", "id": "episode-1"},
+    ]
+    assert not _has_key(response.backends["everos"].result, "vector")
+
+
+def _has_key(value, key: str) -> bool:
+    if isinstance(value, dict):
+        return key in value or any(_has_key(item, key) for item in value.values())
+    if isinstance(value, list):
+        return any(_has_key(item, key) for item in value)
+    return False
+
+
 def test_ingest_splits_user_and_assistant_messages():
     openviking = FakeOpenViking()
     everos = FakeEverOS()