fix(vector_stores): keep config-defined vector stores when /vector_store/list reconciles with the DB

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/proxy/vector_store_endpoints/management_endpoints.py

@@ -613,6 +613,7 @@ async def list_vector_stores(
         # Process in-memory vector stores
         if litellm.vector_store_registry is not None:
             in_memory_vector_stores: Final = copy.deepcopy(litellm.vector_store_registry.vector_stores)
+            config_vector_store_ids: Final = litellm.vector_store_registry.config_vector_store_ids
 
             vector_stores_to_delete_from_memory: Final[list[str]] = []
 
@@ -621,8 +622,7 @@ async def list_vector_stores(
                 if not vector_store_id:
                     continue
 
-                # If vector store is in memory but NOT in database, it was deleted
-                if vector_store_id not in db_vector_store_ids:
+                if vector_store_id not in db_vector_store_ids and vector_store_id not in config_vector_store_ids:
                     verbose_proxy_logger.info(
                         "Vector store %s exists in memory but not in database - marking for deletion from cache",
                         vector_store_id,

litellm/vector_stores/vector_store_registry.py

@@ -104,6 +104,7 @@ class VectorStoreRegistry:
     def __init__(self, vector_stores: list[LiteLLM_ManagedVectorStore] = []):
         self.vector_stores: list[LiteLLM_ManagedVectorStore] = vector_stores
         self.vector_store_ids_to_vector_store_map: dict[str, LiteLLM_ManagedVectorStore] = {}
+        self.config_vector_store_ids: set[str] = set()
 
     def _extract_tool_params(self, tool: dict) -> VectorStoreToolParams:
         """
@@ -429,6 +430,7 @@ class VectorStoreRegistry:
                 updated_at=datetime.now(timezone.utc),
             )
             self.vector_stores.append(litellm_managed_vector_store)
+            self.config_vector_store_ids.add(vector_store_id)
 
         verbose_logger.debug(
             "all loaded vector stores = %s",
@@ -474,6 +476,7 @@ class VectorStoreRegistry:
             for vector_store in self.vector_stores
             if vector_store.get("vector_store_id") != vector_store_id
         ]
+        self.config_vector_store_ids.discard(vector_store_id)
 
     def update_vector_store_in_registry(self, vector_store_id: str, updated_data: LiteLLM_ManagedVectorStore):
         """Update or add a vector store in the registry"""

tests/test_litellm/proxy/vector_store_endpoints/test_vector_store_endpoints.py

@@ -2002,6 +2002,54 @@ async def test_vector_store_update_and_list_synchronization():
     ), "List should return updated data from database"
 
 
+@pytest.mark.asyncio
+async def test_list_vector_stores_keeps_config_defined_store_missing_from_db():
+    """
+    Stores from config.yaml `vector_store_registry` are only loaded in memory and never written
+    to the DB. Listing must not treat that DB miss as a deletion and evict them, while a
+    DB-sourced store that disappeared from the DB is still evicted.
+    """
+    from litellm.proxy.vector_store_endpoints.management_endpoints import list_vector_stores
+    from litellm.vector_stores.vector_store_registry import VectorStoreRegistry
+
+    registry = VectorStoreRegistry(vector_stores=[])
+    registry.load_vector_stores_from_config(
+        [
+            {
+                "vector_store_name": "config-search-store",
+                "litellm_params": {
+                    "vector_store_id": "config-search-store",
+                    "custom_llm_provider": "azure_ai",
+                    "api_key": "fake",
+                    "api_base": "https://example.search.windows.net",
+                },
+            }
+        ]
+    )
+    stale_db_store: LiteLLM_ManagedVectorStore = {
+        "vector_store_id": "deleted-elsewhere",
+        "custom_llm_provider": "bedrock",
+        "litellm_params": {"vector_store_id": "deleted-elsewhere", "custom_llm_provider": "bedrock"},
+    }
+    registry.add_vector_store_to_registry(vector_store=stale_db_store)
+
+    admin = UserAPIKeyAuth(user_role=LitellmUserRoles.PROXY_ADMIN.value, user_id="admin")
+    with (
+        patch.dict("litellm.proxy.proxy_server.general_settings", {}, clear=True),
+        patch("litellm.proxy.proxy_server.prisma_client", MagicMock()),
+        patch.object(litellm, "vector_store_registry", registry),
+        patch(
+            "litellm.proxy.vector_store_endpoints.management_endpoints.VectorStoreRegistry._get_vector_stores_from_db",
+            new=AsyncMock(return_value=[]),
+        ),
+    ):
+        response = await list_vector_stores(user_api_key_dict=admin)
+
+    assert [vs.get("vector_store_id") for vs in response["data"]] == ["config-search-store"]
+    assert registry.get_litellm_managed_vector_store_from_registry_by_name("config-search-store") is not None
+    assert registry.get_litellm_managed_vector_store_from_registry("deleted-elsewhere") is None
+
+
 @pytest.mark.asyncio
 async def test_resolve_embedding_config_from_db():
     """Test that _resolve_embedding_config_from_db correctly resolves embedding config from database."""