diff --git a/api/tests/unit_tests/core/rag/datasource/keyword/jieba/test_stopwords.py b/api/tests/unit_tests/core/rag/datasource/keyword/jieba/test_stopwords.py
index 4375d854ba7..0b32705a097 100644
--- a/api/tests/unit_tests/core/rag/datasource/keyword/jieba/test_stopwords.py
+++ b/api/tests/unit_tests/core/rag/datasource/keyword/jieba/test_stopwords.py
@@ -1,7 +1,7 @@
 from core.rag.datasource.keyword.jieba.stopwords import STOPWORDS
 
 
-def test_stopwords_loaded():
+def test_stopwords_loaded() -> None:
     assert isinstance(STOPWORDS, frozenset)
     assert "during" in STOPWORDS
     assert "the" in STOPWORDS
diff --git a/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_base.py b/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_base.py
index e3b781d3168..c3d2eba835c 100644
--- a/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_base.py
+++ b/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_base.py
@@ -1,4 +1,3 @@
-from types import SimpleNamespace
 from typing import override
 
 import pytest
@@ -16,61 +15,61 @@ def _dataset() -> Dataset:
 
 class _KeywordThatRaises(BaseKeyword):
     @override
-    def create(self, texts: list[Document], session, **kwargs):
+    def create(self, texts: list[Document], session: Session, **kwargs: object) -> BaseKeyword:
         return super().create(texts, session, **kwargs)
 
     @override
-    def add_texts(self, texts: list[Document], session, **kwargs):
+    def add_texts(self, texts: list[Document], session: Session, **kwargs: object) -> None:
         return super().add_texts(texts, session, **kwargs)
 
     @override
-    def text_exists(self, id: str, *, session) -> bool:
+    def text_exists(self, id: str, *, session: Session) -> bool:
         return super().text_exists(id, session=session)
 
     @override
-    def delete_by_ids(self, ids: list[str], session, **kwargs):
+    def delete_by_ids(self, ids: list[str], session: Session, **kwargs: object) -> None:
         return super().delete_by_ids(ids, session, **kwargs)
 
     @override
-    def delete(self, *, session):
+    def delete(self, *, session: Session) -> None:
         return super().delete(session=session)
 
     @override
-    def search(self, query: str, *, session, **kwargs):
+    def search(self, query: str, *, session: Session, **kwargs: object) -> list[Document]:
         return super().search(query, session=session, **kwargs)
 
 
 class _KeywordForHelpers(BaseKeyword):
-    def __init__(self, dataset, existing_ids: set[str] | None = None):
+    def __init__(self, dataset: Dataset, existing_ids: set[str] | None = None) -> None:
         super().__init__(dataset)
         self._existing_ids = existing_ids or set()
 
     @override
-    def create(self, texts: list[Document], session, **kwargs):
+    def create(self, texts: list[Document], session: Session, **kwargs: object) -> BaseKeyword:
         return self
 
     @override
-    def add_texts(self, texts: list[Document], session, **kwargs):
+    def add_texts(self, texts: list[Document], session: Session, **kwargs: object) -> None:
         return None
 
     @override
-    def text_exists(self, id: str, *, session) -> bool:
+    def text_exists(self, id: str, *, session: Session) -> bool:
         return id in self._existing_ids
 
     @override
-    def delete_by_ids(self, ids: list[str], session, **kwargs):
+    def delete_by_ids(self, ids: list[str], session: Session, **kwargs: object) -> None:
         return None
 
     @override
-    def delete(self, *, session):
+    def delete(self, *, session: Session) -> None:
         return None
 
     @override
-    def search(self, query: str, *, session, **kwargs):
+    def search(self, query: str, *, session: Session, **kwargs: object) -> list[Document]:
         return []
 
 
-def test_abstract_methods_raise_not_implemented(unbound_session: Session):
+def test_abstract_methods_raise_not_implemented(unbound_session: Session) -> None:
     keyword = _KeywordThatRaises(_dataset())
     session = unbound_session
 
@@ -93,12 +92,12 @@ def test_abstract_methods_raise_not_implemented(unbound_session: Session):
         keyword.search("query", session=session)
 
 
-def test_filter_duplicate_texts_removes_existing_doc_ids(unbound_session: Session):
+def test_filter_duplicate_texts_removes_existing_doc_ids(unbound_session: Session) -> None:
     keyword = _KeywordForHelpers(_dataset(), existing_ids={"duplicate"})
     texts = [
         Document(page_content="keep", metadata={"doc_id": "keep"}),
         Document(page_content="duplicate", metadata={"doc_id": "duplicate"}),
-        SimpleNamespace(page_content="without-metadata", metadata=None),
+        Document.model_construct(page_content="without-metadata", metadata=None),
     ]
 
     filtered = keyword._filter_duplicate_texts(texts, session=unbound_session)
@@ -107,12 +106,12 @@ def test_filter_duplicate_texts_removes_existing_doc_ids(unbound_session: Sessio
     assert any(text.metadata is None for text in filtered)
 
 
-def test_get_uuids_returns_only_docs_with_metadata():
+def test_get_uuids_returns_only_docs_with_metadata() -> None:
     keyword = _KeywordForHelpers(_dataset())
     texts = [
         Document(page_content="doc-1", metadata={"doc_id": "doc-1"}),
         Document(page_content="doc-2", metadata={"doc_id": "doc-2"}),
-        SimpleNamespace(page_content="doc-3", metadata=None),
+        Document.model_construct(page_content="doc-3", metadata=None),
     ]
 
     assert keyword._get_uuids(texts) == ["doc-1", "doc-2"]
diff --git a/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_factory.py b/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_factory.py
index 9b392493eda..21a82f48ec3 100644
--- a/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_factory.py
+++ b/api/tests/unit_tests/core/rag/datasource/keyword/test_keyword_factory.py
@@ -12,24 +12,24 @@ from models.dataset import Dataset
 from tests.unit_tests.config_override import apply_config_overrides
 
 
-def test_get_keyword_factory_returns_jieba_factory(monkeypatch: pytest.MonkeyPatch):
+def test_get_keyword_factory_returns_jieba_factory(monkeypatch: pytest.MonkeyPatch) -> None:
     fake_module = types.ModuleType("core.rag.datasource.keyword.jieba.jieba")
 
     class FakeJieba:
         pass
 
-    fake_module.Jieba = FakeJieba
+    vars(fake_module)["Jieba"] = FakeJieba
     monkeypatch.setitem(sys.modules, "core.rag.datasource.keyword.jieba.jieba", fake_module)
 
     assert Keyword.get_keyword_factory(KeyWordType.JIEBA) is FakeJieba
 
 
-def test_get_keyword_factory_raises_for_unsupported_type():
+def test_get_keyword_factory_raises_for_unsupported_type() -> None:
     with pytest.raises(ValueError, match="Keyword store unsupported is not supported"):
         Keyword.get_keyword_factory("unsupported")
 
 
-def test_keyword_initialization_uses_configured_factory(monkeypatch: pytest.MonkeyPatch):
+def test_keyword_initialization_uses_configured_factory(monkeypatch: pytest.MonkeyPatch) -> None:
     dataset = Dataset(
         id="dataset-1",
         tenant_id="tenant-1",
@@ -47,7 +47,7 @@ def test_keyword_initialization_uses_configured_factory(monkeypatch: pytest.Monk
     assert keyword._keyword_processor is fake_processor
 
 
-def test_keyword_methods_forward_to_processor(unbound_session: Session):
+def test_keyword_methods_forward_to_processor(unbound_session: Session) -> None:
     processor = MagicMock()
     processor.text_exists.return_value = True
     processor.search.return_value = [Document(page_content="matched", metadata={"doc_id": "doc-1"})]
@@ -72,22 +72,22 @@ def test_keyword_methods_forward_to_processor(unbound_session: Session):
     processor.search.assert_called_once_with("query", session=session, top_k=1)
 
 
-def test_keyword_getattr_returns_callable_and_raises_for_invalid_attributes():
+def test_keyword_getattr_returns_callable_and_raises_for_invalid_attributes() -> None:
     class Processor:
         value = 1
 
         @staticmethod
-        def custom():
+        def custom() -> str:
             return "ok"
 
     keyword = Keyword.__new__(Keyword)
-    keyword._keyword_processor = Processor()
+    keyword._keyword_processor = Processor()  # pyrefly: ignore[bad-assignment]
 
     assert keyword.custom() == "ok"
 
     with pytest.raises(AttributeError):
         _ = keyword.value
 
-    keyword._keyword_processor = None
+    keyword._keyword_processor = None  # pyrefly: ignore[bad-assignment]
     with pytest.raises(AttributeError):
         _ = keyword.missing_method
diff --git a/api/tests/unit_tests/core/rag/datasource/vdb/test_field.py b/api/tests/unit_tests/core/rag/datasource/vdb/test_field.py
index d68c93b021b..6a614f07a1c 100644
--- a/api/tests/unit_tests/core/rag/datasource/vdb/test_field.py
+++ b/api/tests/unit_tests/core/rag/datasource/vdb/test_field.py
@@ -4,42 +4,42 @@ from core.rag.datasource.vdb.field import parse_metadata_json
 
 
 class TestParseMetadataJson:
-    def test_none_returns_empty_dict(self):
+    def test_none_returns_empty_dict(self) -> None:
         assert parse_metadata_json(None) == {}
 
-    def test_empty_string_returns_empty_dict(self):
+    def test_empty_string_returns_empty_dict(self) -> None:
         assert parse_metadata_json("") == {}
 
-    def test_valid_json_string(self):
+    def test_valid_json_string(self) -> None:
         result = parse_metadata_json('{"doc_id": "abc", "score": 0.9}')
         assert result == {"doc_id": "abc", "score": 0.9}
 
-    def test_dict_passthrough(self):
+    def test_dict_passthrough(self) -> None:
         original = {"doc_id": "abc", "document_id": "123"}
         result = parse_metadata_json(original)
         assert result == original
 
-    def test_empty_json_object(self):
+    def test_empty_json_object(self) -> None:
         assert parse_metadata_json("{}") == {}
 
-    def test_invalid_json_raises_value_error(self):
+    def test_invalid_json_raises_value_error(self) -> None:
         with pytest.raises(ValueError):
             parse_metadata_json("{invalid json")
 
-    def test_nested_metadata(self):
+    def test_nested_metadata(self) -> None:
         result = parse_metadata_json('{"doc_id": "1", "extra": {"nested": true}}')
         assert result["extra"]["nested"] is True
 
-    def test_non_str_non_dict_returns_empty_dict(self):
+    def test_non_str_non_dict_returns_empty_dict(self) -> None:
         assert parse_metadata_json(123) == {}
         assert parse_metadata_json([1, 2]) == {}
 
-    def test_bytes_input(self):
+    def test_bytes_input(self) -> None:
         result = parse_metadata_json(b'{"key": "value"}')
         assert result == {"key": "value"}
 
-    def test_empty_bytes_returns_empty_dict(self):
+    def test_empty_bytes_returns_empty_dict(self) -> None:
         assert parse_metadata_json(b"") == {}
 
-    def test_empty_bytearray_returns_empty_dict(self):
+    def test_empty_bytearray_returns_empty_dict(self) -> None:
         assert parse_metadata_json(bytearray(b"")) == {}
diff --git a/api/tests/unit_tests/core/rag/datasource/vdb/test_vector_base.py b/api/tests/unit_tests/core/rag/datasource/vdb/test_vector_base.py
index fdbdd1833ed..8e2890c65a0 100644
--- a/api/tests/unit_tests/core/rag/datasource/vdb/test_vector_base.py
+++ b/api/tests/unit_tests/core/rag/datasource/vdb/test_vector_base.py
@@ -1,4 +1,4 @@
-from types import SimpleNamespace
+from collections.abc import Callable
 from typing import override
 
 import pytest
@@ -8,7 +8,7 @@ from core.rag.models.document import Document
 
 
 class _DummyVector(BaseVector):
-    def __init__(self, collection_name: str, existing_ids: set[str] | None = None):
+    def __init__(self, collection_name: str, existing_ids: set[str] | None = None) -> None:
         super().__init__(collection_name)
         self._existing_ids = existing_ids or set()
 
@@ -17,35 +17,35 @@ class _DummyVector(BaseVector):
         return "dummy"
 
     @override
-    def create(self, texts: list[Document], embeddings: list[list[float]], **kwargs):
+    def create(self, texts: list[Document], embeddings: list[list[float]], **kwargs: object) -> None:
         return None
 
     @override
-    def add_texts(self, documents: list[Document], embeddings: list[list[float]], **kwargs):
-        return None
+    def add_texts(self, documents: list[Document], embeddings: list[list[float]], **kwargs: object) -> list[str]:
+        return []
 
     @override
     def text_exists(self, id: str) -> bool:
         return id in self._existing_ids
 
     @override
-    def delete_by_ids(self, ids: list[str]):
+    def delete_by_ids(self, ids: list[str]) -> None:
         return None
 
     @override
-    def delete_by_metadata_field(self, key: str, value: str):
+    def delete_by_metadata_field(self, key: str, value: str) -> None:
         return None
 
     @override
-    def search_by_vector(self, query_vector: list[float], **kwargs):
+    def search_by_vector(self, query_vector: list[float], **kwargs: object) -> list[Document]:
         return []
 
     @override
-    def search_by_full_text(self, query: str, **kwargs):
+    def search_by_full_text(self, query: str, **kwargs: object) -> list[Document]:
         return []
 
     @override
-    def delete(self):
+    def delete(self) -> None:
         return None
 
 
@@ -64,17 +64,19 @@ class _DummyVector(BaseVector):
         (BaseVector.delete, ()),
     ],
 )
-def test_base_vector_default_methods_raise_not_implemented(base_method, args):
+def test_base_vector_default_methods_raise_not_implemented(
+    base_method: Callable[..., object], args: tuple[object, ...]
+) -> None:
     vector = _DummyVector("collection_1")
 
     with pytest.raises(NotImplementedError):
         base_method(vector, *args)
 
 
-def test_filter_duplicate_texts_removes_existing_docs():
+def test_filter_duplicate_texts_removes_existing_docs() -> None:
     vector = _DummyVector("collection_1", existing_ids={"dup"})
     docs = [
-        SimpleNamespace(page_content="keep-no-meta", metadata=None),
+        Document.model_construct(page_content="keep-no-meta", metadata=None),
         Document(page_content="keep-no-doc-id", metadata={"document_id": "d1"}),
         Document(page_content="remove-dup", metadata={"doc_id": "dup"}),
         Document(page_content="keep-unique", metadata={"doc_id": "unique"}),
@@ -85,11 +87,11 @@ def test_filter_duplicate_texts_removes_existing_docs():
     assert [d.page_content for d in filtered] == ["keep-no-meta", "keep-no-doc-id", "keep-unique"]
 
 
-def test_get_uuids_and_collection_name_property():
+def test_get_uuids_and_collection_name_property() -> None:
     vector = _DummyVector("collection_1")
     docs = [
         Document(page_content="a", metadata={"doc_id": "id-1"}),
-        SimpleNamespace(page_content="b", metadata=None),
+        Document.model_construct(page_content="b", metadata=None),
         Document(page_content="c", metadata={"document_id": "d-1"}),
         Document(page_content="d", metadata={"doc_id": "id-2"}),
     ]
diff --git a/api/tests/unit_tests/pyrefly.toml b/api/tests/unit_tests/pyrefly.toml
index ce5f95cfea7..f94177096bf 100644
--- a/api/tests/unit_tests/pyrefly.toml
+++ b/api/tests/unit_tests/pyrefly.toml
@@ -393,12 +393,7 @@ project-excludes = [
   "core/rag/data_post_processor/test_data_post_processor.py",
   "core/rag/datasource/keyword/jieba/test_jieba.py",
   "core/rag/datasource/keyword/jieba/test_jieba_keyword_table_handler.py",
-  "core/rag/datasource/keyword/jieba/test_stopwords.py",
-  "core/rag/datasource/keyword/test_keyword_base.py",
-  "core/rag/datasource/keyword/test_keyword_factory.py",
   "core/rag/datasource/test_datasource_retrieval.py",
-  "core/rag/datasource/vdb/test_field.py",
-  "core/rag/datasource/vdb/test_vector_base.py",
   "core/rag/datasource/vdb/test_vector_factory.py",
   "core/rag/embedding/test_embedding_base.py",
   "core/rag/embedding/test_embedding_service.py",