diff --git a/cognite/client/_api/__init__.py b/cognite/client/_api/__init__.py
index e69de29bb2..9d48db4f9f 100644
--- a/cognite/client/_api/__init__.py
+++ b/cognite/client/_api/__init__.py
@@ -0,0 +1 @@
+from __future__ import annotations
diff --git a/cognite/client/_api/data_modeling/_data_modeling_executor.py b/cognite/client/_api/data_modeling/_data_modeling_executor.py
index 6fa5c61b49..9db31d1171 100644
--- a/cognite/client/_api/data_modeling/_data_modeling_executor.py
+++ b/cognite/client/_api/data_modeling/_data_modeling_executor.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from concurrent.futures import ThreadPoolExecutor
 
 from cognite.client.utils._concurrency import ConcurrencySettings, MainThreadExecutor, TaskExecutor
diff --git a/cognite/client/data_classes/__init__.py b/cognite/client/data_classes/__init__.py
index 516cf1b4f3..4598d30e4e 100644
--- a/cognite/client/data_classes/__init__.py
+++ b/cognite/client/data_classes/__init__.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from cognite.client.data_classes.annotations import (
     Annotation,
     AnnotationFilter,
diff --git a/cognite/client/data_classes/annotation_types/__init__.py b/cognite/client/data_classes/annotation_types/__init__.py
index e69de29bb2..9d48db4f9f 100644
--- a/cognite/client/data_classes/annotation_types/__init__.py
+++ b/cognite/client/data_classes/annotation_types/__init__.py
@@ -0,0 +1 @@
+from __future__ import annotations
diff --git a/cognite/client/data_classes/data_modeling/__init__.py b/cognite/client/data_classes/data_modeling/__init__.py
index 342510b3a3..a2aeeb6d58 100644
--- a/cognite/client/data_classes/data_modeling/__init__.py
+++ b/cognite/client/data_classes/data_modeling/__init__.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from cognite.client.data_classes import filters
 from cognite.client.data_classes.data_modeling import aggregations, query
 from cognite.client.data_classes.data_modeling.aggregations import AggregatedValue, Aggregation
diff --git a/cognite/client/utils/_auxiliary.py b/cognite/client/utils/_auxiliary.py
index 2cadde6cbb..3730d3c794 100644
--- a/cognite/client/utils/_auxiliary.py
+++ b/cognite/client/utils/_auxiliary.py
@@ -1,9 +1,3 @@
-"""Utilities for Cognite API SDK
-
-This module provides helper methods and different utilities for the Cognite API Python SDK.
-
-This module is protected and should not be used by end-users.
-"""
 from __future__ import annotations
 
 import functools
diff --git a/cognite/client/utils/_graph.py b/cognite/client/utils/_graph.py
index fcbe114cc2..8ff0e7f128 100644
--- a/cognite/client/utils/_graph.py
+++ b/cognite/client/utils/_graph.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from typing import Dict, List, Set, Tuple
 
 
diff --git a/tests/tests_unit/test_meta.py b/tests/tests_unit/test_meta.py
index 64d090646e..b60ce6851b 100644
--- a/tests/tests_unit/test_meta.py
+++ b/tests/tests_unit/test_meta.py
@@ -9,3 +9,20 @@ def test_assert_no_root_init_file():
     # or uses a pkgutil-style __init__.py. If any distribution does not, it will cause the namespace logic to
     # fail and the other sub-packages will not be importable"
     assert not Path("cognite/__init__.py").exists()
+
+
+def test_ensure_all_files_use_future_annots():
+    def keep(path):
+        skip_list = [
+            "_pb2.py",  # Auto-generated, dislikes changes ;)
+            "cognite/client/utils/_priority_tpe.py",  # Module docstring at the top takes priority
+        ]
+        return all(skip not in str(path.as_posix()) for skip in skip_list)
+
+    all_filepaths = filter(keep, Path("cognite/client/").glob("**/*.py"))
+    err_msg = "File: '{}' is missing 'from __future__ import annotations' at line=0"
+
+    for filepath in all_filepaths:
+        with filepath.open("r") as file:
+            # We just read the first line from each file:
+            assert file.readline() == "from __future__ import annotations\n", err_msg.format(filepath)