fix: improve KVStore initialization checks in vector store adapters

src/llama_stack/providers/inline/vector_io/faiss/faiss.py

@@ -223,7 +223,8 @@ class FaissVectorIOAdapter(OpenAIVectorStoreMixin, VectorIO, VectorStoresProtoco
             return HealthResponse(status=HealthStatus.ERROR, message=f"Health check failed: {str(e)}")
 
     async def register_vector_store(self, vector_store: VectorStore) -> None:
-        assert self.kvstore is not None
+        if self.kvstore is None:
+            raise RuntimeError("KVStore not initialized. Call initialize() before registering vector stores.")
 
         key = f"{VECTOR_DBS_PREFIX}{vector_store.identifier}"
         await self.kvstore.set(key=key, value=vector_store.model_dump_json())
@@ -239,7 +240,8 @@ class FaissVectorIOAdapter(OpenAIVectorStoreMixin, VectorIO, VectorStoresProtoco
         return [i.vector_store for i in self.cache.values()]
 
     async def unregister_vector_store(self, vector_store_id: str) -> None:
-        assert self.kvstore is not None
+        if self.kvstore is None:
+            raise RuntimeError("KVStore not initialized. Call initialize() before unregistering vector stores.")
 
         if vector_store_id not in self.cache:
             return
@@ -248,6 +250,27 @@ class FaissVectorIOAdapter(OpenAIVectorStoreMixin, VectorIO, VectorStoresProtoco
         del self.cache[vector_store_id]
         await self.kvstore.delete(f"{VECTOR_DBS_PREFIX}{vector_store_id}")
 
+    async def _get_and_cache_vector_store_index(self, vector_store_id: str) -> VectorStoreWithIndex | None:
+        if vector_store_id in self.cache:
+            return self.cache[vector_store_id]
+
+        if self.kvstore is None:
+            raise RuntimeError("KVStore not initialized. Call initialize() before using vector stores.")
+
+        key = f"{VECTOR_DBS_PREFIX}{vector_store_id}"
+        vector_store_data = await self.kvstore.get(key)
+        if not vector_store_data:
+            raise VectorStoreNotFoundError(vector_store_id)
+
+        vector_store = VectorStore.model_validate_json(vector_store_data)
+        index = VectorStoreWithIndex(
+            vector_store=vector_store,
+            index=await FaissIndex.create(vector_store.embedding_dimension, self.kvstore, vector_store.identifier),
+            inference_api=self.inference_api,
+        )
+        self.cache[vector_store_id] = index
+        return index
+
     async def insert_chunks(self, vector_store_id: str, chunks: list[Chunk], ttl_seconds: int | None = None) -> None:
         index = self.cache.get(vector_store_id)
         if index is None:

src/llama_stack/providers/inline/vector_io/sqlite_vec/sqlite_vec.py

@@ -412,6 +412,14 @@ class SQLiteVecVectorIOAdapter(OpenAIVectorStoreMixin, VectorIO, VectorStoresPro
         return [v.vector_store for v in self.cache.values()]
 
     async def register_vector_store(self, vector_store: VectorStore) -> None:
+        if self.kvstore is None:
+            raise RuntimeError("KVStore not initialized. Call initialize() before registering vector stores.")
+
+        # Save to kvstore for persistence
+        key = f"{VECTOR_DBS_PREFIX}{vector_store.identifier}"
+        await self.kvstore.set(key=key, value=vector_store.model_dump_json())
+
+        # Create and cache the index
         index = await SQLiteVecIndex.create(
             vector_store.embedding_dimension, self.config.db_path, vector_store.identifier
         )

src/llama_stack/providers/remote/vector_io/pgvector/pgvector.py

@@ -395,6 +395,11 @@ class PGVectorVectorIOAdapter(OpenAIVectorStoreMixin, VectorIO, VectorStoresProt
         # Persist vector DB metadata in the KV store
         if self.kvstore is None:
             raise RuntimeError("KVStore not initialized. Call initialize() before registering vector stores.")
+
+        # Save to kvstore for persistence
+        key = f"{VECTOR_DBS_PREFIX}{vector_store.identifier}"
+        await self.kvstore.set(key=key, value=vector_store.model_dump_json())
+
         # Upsert model metadata in Postgres
         upsert_models(self.conn, [(vector_store.identifier, vector_store)])