From 88eba82c8bf10ce99a68958b750217ac9c728cba Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 13:34:47 +0900
Subject: [PATCH 01/11] =?UTF-8?q?=E3=82=A2=E3=83=8E=E3=83=86=E3=83=BC?=
 =?UTF-8?q?=E3=82=B7=E3=83=A7=E3=83=B3=E3=82=AF=E3=83=A9=E3=82=B9=E4=BD=9C?=
 =?UTF-8?q?=E6=88=90=E3=81=A7=E9=A0=98=E5=9F=9F=E6=95=B0=E4=B8=8A=E9=99=90?=
 =?UTF-8?q?=E3=82=92=E6=8C=87=E5=AE=9A=E3=81=A7=E3=81=8D=E3=82=8B=E3=82=88?=
 =?UTF-8?q?=E3=81=86=E3=81=AB=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md                | 11 ++++++
 fastlabel/__init__.py    |  6 ++++
 tests/test_annotation.py | 77 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 tests/test_annotation.py

diff --git a/README.md b/README.md
index 6261a9e..39136ea 100644
--- a/README.md
+++ b/README.md
@@ -2665,6 +2665,17 @@ annotation_id = client.create_annotation(
     project="YOUR_PROJECT_SLUG", type="bbox", value="cat", title="Cat", color="#FF0000", attributes=attributes)
 ```
 
+Create a new segmentation annotation that allows disjoint regions.
+
+`max_area_count` is the maximum number of separate regions a single segmentation annotation may
+consist of. It only applies to segmentation classes and defaults to `1`, which disallows disjoint
+regions. Set `None` to allow any number of regions.
+
+```python
+annotation_id = client.create_annotation(
+    project="YOUR_PROJECT_SLUG", type="segmentation", value="cat", title="Cat", max_area_count=None)
+```
+
 Create a new classification annotation.
 
 ```python
diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index fa28612..ef4b585 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -4297,6 +4297,7 @@ def create_annotation(
         color: str = None,
         order: int = None,
         attributes: list = [],
+        max_area_count: Optional[int] = 1,
     ) -> str:
         """
         Create an annotation.
@@ -4308,6 +4309,10 @@ def create_annotation(
         title is a display name of value (Required).
         color is hex color code like #ffffff (Optional).
         attributes is a list of attribute (Optional).
+        max_area_count is the maximum number of separate regions a single
+        segmentation annotation may consist of, between 1 and 1000 (Optional).
+        It only applies to segmentation classes and defaults to 1, which
+        disallows disjoint regions. Set None to allow any number of regions.
         """
         endpoint = "annotations"
         payload = {
@@ -4315,6 +4320,7 @@ def create_annotation(
             "type": type,
             "value": value,
             "title": title,
+            "maxAreaCount": max_area_count,
         }
         if color:
             payload["color"] = color
diff --git a/tests/test_annotation.py b/tests/test_annotation.py
new file mode 100644
index 0000000..43baa43
--- /dev/null
+++ b/tests/test_annotation.py
@@ -0,0 +1,77 @@
+"""Tests for the annotation class API client methods.
+
+These verify that create_annotation builds the correct endpoint and payload,
+with a focus on max_area_count. The HTTP layer (client.api.*_request) is
+stubbed so no real request is made.
+"""
+
+import pytest
+
+import fastlabel
+
+
+@pytest.fixture
+def client(monkeypatch):
+    monkeypatch.setenv("FASTLABEL_ACCESS_TOKEN", "dummy-token")
+    return fastlabel.Client()
+
+
+def _capture(monkeypatch, client, method_name, return_value=None):
+    """Replace an api.*_request method with a recorder and return the calls list."""
+    calls = []
+
+    def fake(endpoint, *args, **kwargs):
+        calls.append({"endpoint": endpoint, "args": args, "kwargs": kwargs})
+        return return_value
+
+    monkeypatch.setattr(client.api, method_name, fake)
+    return calls
+
+
+# --- create_annotation -----------------------------------------------------
+
+
+def test_create_annotation_defaults_max_area_count_to_one(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+
+    client.create_annotation(
+        project="my-project", type="segmentation", value="cat", title="Cat"
+    )
+
+    assert calls[0]["endpoint"] == "annotations"
+    assert calls[0]["kwargs"]["payload"] == {
+        "project": "my-project",
+        "type": "segmentation",
+        "value": "cat",
+        "title": "Cat",
+        "maxAreaCount": 1,
+    }
+
+
+def test_create_annotation_with_max_area_count(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+
+    client.create_annotation(
+        project="my-project",
+        type="segmentation",
+        value="cat",
+        title="Cat",
+        max_area_count=10,
+    )
+
+    assert calls[0]["kwargs"]["payload"]["maxAreaCount"] == 10
+
+
+def test_create_annotation_without_max_area_count_limit(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+
+    client.create_annotation(
+        project="my-project",
+        type="segmentation",
+        value="cat",
+        title="Cat",
+        max_area_count=None,
+    )
+
+    # None is sent as an explicit null, which means no limit on the server side
+    assert calls[0]["kwargs"]["payload"]["maxAreaCount"] is None

From bd6216df7d52be047a2ae19e5ca70dc1be5a5344 Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 13:35:58 +0900
Subject: [PATCH 02/11] =?UTF-8?q?=E3=82=A2=E3=83=8E=E3=83=86=E3=83=BC?=
 =?UTF-8?q?=E3=82=B7=E3=83=A7=E3=83=B3=E3=82=AF=E3=83=A9=E3=82=B9=E6=9B=B4?=
 =?UTF-8?q?=E6=96=B0=E3=81=A7=E9=A0=98=E5=9F=9F=E6=95=B0=E4=B8=8A=E9=99=90?=
 =?UTF-8?q?=E3=82=92=E5=A4=89=E6=9B=B4=E3=81=A7=E3=81=8D=E3=82=8B=E3=82=88?=
 =?UTF-8?q?=E3=81=86=E3=81=AB=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md                |  9 +++++++++
 fastlabel/__init__.py    | 21 +++++++++++++++++++++
 tests/test_annotation.py | 35 ++++++++++++++++++++++++++++++++---
 3 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 39136ea..c5c1b72 100644
--- a/README.md
+++ b/README.md
@@ -2842,6 +2842,15 @@ annotation_id = client.update_annotation(
     annotation_id="YOUR_ANNOTATION_ID", value="cat2", title="Cat2", color="#FF0000", attributes=attributes)
 ```
 
+Update the maximum number of regions of a segmentation annotation.
+
+`max_area_count` is left unchanged when omitted. Set `None` to allow any number of regions.
+
+```python
+annotation_id = client.update_annotation(
+    annotation_id="YOUR_ANNOTATION_ID", max_area_count=None)
+```
+
 Update a classification annotation.
 
 ```python
diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index ef4b585..fc59e01 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -39,6 +39,20 @@
 )
 
 
+class _Unset:
+    """Marker for arguments the caller did not pass.
+
+    Needed where None is a meaningful value that has to be sent to the API,
+    and therefore cannot double as "leave this field untouched".
+    """
+
+    def __repr__(self) -> str:
+        return "UNSET"
+
+
+_UNSET = _Unset()
+
+
 class Client:
     api = None
 
@@ -4349,6 +4363,7 @@ def update_annotation(
         color: str = None,
         order: int = None,
         attributes: list = [],
+        max_area_count: Union[int, None, _Unset] = _UNSET,
     ) -> str:
         """
         Update an annotation.
@@ -4358,6 +4373,10 @@ def update_annotation(
         title is a display name of value (Optional).
         color is hex color code like #ffffff (Optional).
         attributes is a list of attribute (Optional).
+        max_area_count is the maximum number of separate regions a single
+        segmentation annotation may consist of, between 1 and 1000 (Optional).
+        It only applies to segmentation classes and is left unchanged when
+        omitted. Set None to allow any number of regions.
         """
         endpoint = "annotations/" + annotation_id
         payload = {}
@@ -4371,6 +4390,8 @@ def update_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
+        if not isinstance(max_area_count, _Unset):
+            payload["maxAreaCount"] = max_area_count
         return self.api.put_request(endpoint, payload=payload)
 
     def update_classification_annotation(
diff --git a/tests/test_annotation.py b/tests/test_annotation.py
index 43baa43..9dda849 100644
--- a/tests/test_annotation.py
+++ b/tests/test_annotation.py
@@ -1,8 +1,8 @@
 """Tests for the annotation class API client methods.
 
-These verify that create_annotation builds the correct endpoint and payload,
-with a focus on max_area_count. The HTTP layer (client.api.*_request) is
-stubbed so no real request is made.
+These verify that create_annotation and update_annotation build the correct
+endpoint and payload, with a focus on max_area_count. The HTTP layer
+(client.api.*_request) is stubbed so no real request is made.
 """
 
 import pytest
@@ -75,3 +75,32 @@ def test_create_annotation_without_max_area_count_limit(monkeypatch, client):
 
     # None is sent as an explicit null, which means no limit on the server side
     assert calls[0]["kwargs"]["payload"]["maxAreaCount"] is None
+
+
+# --- update_annotation -----------------------------------------------------
+
+
+def test_update_annotation_omits_max_area_count_by_default(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+
+    client.update_annotation(annotation_id="anno-id", title="Cat")
+
+    assert calls[0]["endpoint"] == "annotations/anno-id"
+    assert calls[0]["kwargs"]["payload"] == {"title": "Cat"}
+
+
+def test_update_annotation_with_max_area_count(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+
+    client.update_annotation(annotation_id="anno-id", max_area_count=10)
+
+    assert calls[0]["kwargs"]["payload"] == {"maxAreaCount": 10}
+
+
+def test_update_annotation_without_max_area_count_limit(monkeypatch, client):
+    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+
+    client.update_annotation(annotation_id="anno-id", max_area_count=None)
+
+    # None is sent as an explicit null, which means no limit on the server side
+    assert calls[0]["kwargs"]["payload"] == {"maxAreaCount": None}

From bcb88fda0f44fbbd87e0145438d8e99e63cd2b9e Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 15:50:21 +0900
Subject: [PATCH 03/11] =?UTF-8?q?=E9=A0=98=E5=9F=9F=E6=95=B0=E4=B8=8A?=
 =?UTF-8?q?=E9=99=90=E3=81=AE=E6=9C=89=E5=8A=B9=E7=AF=84=E5=9B=B2=E3=82=92?=
 =?UTF-8?q?README=E3=81=AB=E6=98=8E=E8=A8=98=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index c5c1b72..2c74433 100644
--- a/README.md
+++ b/README.md
@@ -2668,8 +2668,8 @@ annotation_id = client.create_annotation(
 Create a new segmentation annotation that allows disjoint regions.
 
 `max_area_count` is the maximum number of separate regions a single segmentation annotation may
-consist of. It only applies to segmentation classes and defaults to `1`, which disallows disjoint
-regions. Set `None` to allow any number of regions.
+consist of, between 1 and 1000. It only applies to segmentation classes and defaults to `1`, which
+disallows disjoint regions. Set `None` to allow any number of regions.
 
 ```python
 annotation_id = client.create_annotation(
@@ -2844,7 +2844,8 @@ annotation_id = client.update_annotation(
 
 Update the maximum number of regions of a segmentation annotation.
 
-`max_area_count` is left unchanged when omitted. Set `None` to allow any number of regions.
+`max_area_count` accepts a value between 1 and 1000 and is left unchanged when omitted. Set `None`
+to allow any number of regions.
 
 ```python
 annotation_id = client.update_annotation(

From b098470a481a382a9e0841d76a32aaf37ddd402e Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 16:02:43 +0900
Subject: [PATCH 04/11] =?UTF-8?q?=E3=82=A2=E3=83=8E=E3=83=86=E3=83=BC?=
 =?UTF-8?q?=E3=82=B7=E3=83=A7=E3=83=B3=E3=82=AF=E3=83=A9=E3=82=B9=E4=BD=9C?=
 =?UTF-8?q?=E6=88=90=E3=81=A7max=5Farea=5Fcount=E6=9C=AA=E6=8C=87=E5=AE=9A?=
 =?UTF-8?q?=E6=99=82=E3=81=AF=E3=83=AA=E3=82=AF=E3=82=A8=E3=82=B9=E3=83=88?=
 =?UTF-8?q?=E3=81=AB=E5=90=AB=E3=82=81=E3=81=AA=E3=81=84=E3=82=88=E3=81=86?=
 =?UTF-8?q?=E3=81=AB=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 fastlabel/__init__.py    | 10 ++++++----
 tests/test_annotation.py |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index fc59e01..9b343f3 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -4311,7 +4311,7 @@ def create_annotation(
         color: str = None,
         order: int = None,
         attributes: list = [],
-        max_area_count: Optional[int] = 1,
+        max_area_count: Union[int, None, _Unset] = _UNSET,
     ) -> str:
         """
         Create an annotation.
@@ -4325,8 +4325,9 @@ def create_annotation(
         attributes is a list of attribute (Optional).
         max_area_count is the maximum number of separate regions a single
         segmentation annotation may consist of, between 1 and 1000 (Optional).
-        It only applies to segmentation classes and defaults to 1, which
-        disallows disjoint regions. Set None to allow any number of regions.
+        It only applies to segmentation classes. When omitted the API applies
+        its default of 1, which disallows disjoint regions. Set None to allow
+        any number of regions.
         """
         endpoint = "annotations"
         payload = {
@@ -4334,7 +4335,6 @@ def create_annotation(
             "type": type,
             "value": value,
             "title": title,
-            "maxAreaCount": max_area_count,
         }
         if color:
             payload["color"] = color
@@ -4342,6 +4342,8 @@ def create_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
+        if not isinstance(max_area_count, _Unset):
+            payload["maxAreaCount"] = max_area_count
         return self.api.post_request(endpoint, payload=payload)
 
     def create_classification_annotation(self, project: str, attributes: list) -> str:
diff --git a/tests/test_annotation.py b/tests/test_annotation.py
index 9dda849..950220c 100644
--- a/tests/test_annotation.py
+++ b/tests/test_annotation.py
@@ -31,20 +31,20 @@ def fake(endpoint, *args, **kwargs):
 # --- create_annotation -----------------------------------------------------
 
 
-def test_create_annotation_defaults_max_area_count_to_one(monkeypatch, client):
+def test_create_annotation_omits_max_area_count_by_default(monkeypatch, client):
     calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
 
     client.create_annotation(
         project="my-project", type="segmentation", value="cat", title="Cat"
     )
 
+    # The field is left out entirely so the API applies its own default of 1
     assert calls[0]["endpoint"] == "annotations"
     assert calls[0]["kwargs"]["payload"] == {
         "project": "my-project",
         "type": "segmentation",
         "value": "cat",
         "title": "Cat",
-        "maxAreaCount": 1,
     }
 
 

From d1efbf832fd701bf5e3386bec62781ac02dc0be1 Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 16:03:03 +0900
Subject: [PATCH 05/11] =?UTF-8?q?=E3=82=BB=E3=83=B3=E3=83=81=E3=83=8D?=
 =?UTF-8?q?=E3=83=AB=E3=81=AE=E5=88=A4=E5=AE=9A=E3=82=92isinstance?=
 =?UTF-8?q?=E3=81=8B=E3=82=89=E5=90=8C=E4=B8=80=E6=80=A7=E6=AF=94=E8=BC=83?=
 =?UTF-8?q?=E3=81=AB=E5=A4=89=E3=81=88=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 fastlabel/__init__.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index 9b343f3..9b6946c 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -4342,7 +4342,7 @@ def create_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        if not isinstance(max_area_count, _Unset):
+        if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.post_request(endpoint, payload=payload)
 
@@ -4392,7 +4392,7 @@ def update_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        if not isinstance(max_area_count, _Unset):
+        if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.put_request(endpoint, payload=payload)
 

From 1aa65b69b702bab9ac4212e07c7bfc58ddf6a76c Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 16:05:14 +0900
Subject: [PATCH 06/11] =?UTF-8?q?=E3=83=86=E3=82=B9=E3=83=88=E3=81=AEclien?=
 =?UTF-8?q?t=20fixture=E3=81=A8=E3=83=AA=E3=82=AF=E3=82=A8=E3=82=B9?=
 =?UTF-8?q?=E3=83=88=E8=A8=98=E9=8C=B2=E3=83=98=E3=83=AB=E3=83=91=E3=83=BC?=
 =?UTF-8?q?=E3=82=92conftest=E3=81=B8=E7=A7=BB=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 tests/conftest.py            | 25 +++++++++++++
 tests/test_annotation.py     | 47 +++++++-----------------
 tests/test_workspace_user.py | 69 ++++++++++++++----------------------
 3 files changed, 63 insertions(+), 78 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 7e18f89..140f95a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -4,6 +4,8 @@
 import numpy as np
 import pytest
 
+import fastlabel
+
 
 def _write_synthetic_video(
     path: Path,
@@ -48,3 +50,26 @@ def _factory(
         )
 
     return _factory
+
+
+@pytest.fixture
+def client(monkeypatch):
+    monkeypatch.setenv("FASTLABEL_ACCESS_TOKEN", "dummy-token")
+    return fastlabel.Client()
+
+
+@pytest.fixture
+def capture_request(monkeypatch):
+    """Replace an api.*_request method with a recorder and return the calls list."""
+
+    def _factory(client, method_name, return_value=None):
+        calls = []
+
+        def fake(endpoint, *args, **kwargs):
+            calls.append({"endpoint": endpoint, "args": args, "kwargs": kwargs})
+            return return_value
+
+        monkeypatch.setattr(client.api, method_name, fake)
+        return calls
+
+    return _factory
diff --git a/tests/test_annotation.py b/tests/test_annotation.py
index 950220c..1396b36 100644
--- a/tests/test_annotation.py
+++ b/tests/test_annotation.py
@@ -5,34 +5,11 @@
 (client.api.*_request) is stubbed so no real request is made.
 """
 
-import pytest
-
-import fastlabel
-
-
-@pytest.fixture
-def client(monkeypatch):
-    monkeypatch.setenv("FASTLABEL_ACCESS_TOKEN", "dummy-token")
-    return fastlabel.Client()
-
-
-def _capture(monkeypatch, client, method_name, return_value=None):
-    """Replace an api.*_request method with a recorder and return the calls list."""
-    calls = []
-
-    def fake(endpoint, *args, **kwargs):
-        calls.append({"endpoint": endpoint, "args": args, "kwargs": kwargs})
-        return return_value
-
-    monkeypatch.setattr(client.api, method_name, fake)
-    return calls
-
-
 # --- create_annotation -----------------------------------------------------
 
 
-def test_create_annotation_omits_max_area_count_by_default(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+def test_create_annotation_omits_max_area_count_by_default(client, capture_request):
+    calls = capture_request(client, "post_request", return_value="anno-id")
 
     client.create_annotation(
         project="my-project", type="segmentation", value="cat", title="Cat"
@@ -48,8 +25,8 @@ def test_create_annotation_omits_max_area_count_by_default(monkeypatch, client):
     }
 
 
-def test_create_annotation_with_max_area_count(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+def test_create_annotation_with_max_area_count(client, capture_request):
+    calls = capture_request(client, "post_request", return_value="anno-id")
 
     client.create_annotation(
         project="my-project",
@@ -62,8 +39,8 @@ def test_create_annotation_with_max_area_count(monkeypatch, client):
     assert calls[0]["kwargs"]["payload"]["maxAreaCount"] == 10
 
 
-def test_create_annotation_without_max_area_count_limit(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "post_request", return_value="anno-id")
+def test_create_annotation_without_max_area_count_limit(client, capture_request):
+    calls = capture_request(client, "post_request", return_value="anno-id")
 
     client.create_annotation(
         project="my-project",
@@ -80,8 +57,8 @@ def test_create_annotation_without_max_area_count_limit(monkeypatch, client):
 # --- update_annotation -----------------------------------------------------
 
 
-def test_update_annotation_omits_max_area_count_by_default(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+def test_update_annotation_omits_max_area_count_by_default(client, capture_request):
+    calls = capture_request(client, "put_request", return_value="anno-id")
 
     client.update_annotation(annotation_id="anno-id", title="Cat")
 
@@ -89,16 +66,16 @@ def test_update_annotation_omits_max_area_count_by_default(monkeypatch, client):
     assert calls[0]["kwargs"]["payload"] == {"title": "Cat"}
 
 
-def test_update_annotation_with_max_area_count(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+def test_update_annotation_with_max_area_count(client, capture_request):
+    calls = capture_request(client, "put_request", return_value="anno-id")
 
     client.update_annotation(annotation_id="anno-id", max_area_count=10)
 
     assert calls[0]["kwargs"]["payload"] == {"maxAreaCount": 10}
 
 
-def test_update_annotation_without_max_area_count_limit(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "put_request", return_value="anno-id")
+def test_update_annotation_without_max_area_count_limit(client, capture_request):
+    calls = capture_request(client, "put_request", return_value="anno-id")
 
     client.update_annotation(annotation_id="anno-id", max_area_count=None)
 
diff --git a/tests/test_workspace_user.py b/tests/test_workspace_user.py
index e7729ee..d437286 100644
--- a/tests/test_workspace_user.py
+++ b/tests/test_workspace_user.py
@@ -9,30 +9,11 @@
 
 import fastlabel
 
-
-@pytest.fixture
-def client(monkeypatch):
-    monkeypatch.setenv("FASTLABEL_ACCESS_TOKEN", "dummy-token")
-    return fastlabel.Client()
-
-
-def _capture(monkeypatch, client, method_name, return_value=None):
-    """Replace an api.*_request method with a recorder and return the calls list."""
-    calls = []
-
-    def fake(endpoint, *args, **kwargs):
-        calls.append({"endpoint": endpoint, "args": args, "kwargs": kwargs})
-        return return_value
-
-    monkeypatch.setattr(client.api, method_name, fake)
-    return calls
-
-
 # --- get_workspace_users ---------------------------------------------------
 
 
-def test_get_workspace_users_default(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "get_request", return_value=[])
+def test_get_workspace_users_default(client, capture_request):
+    calls = capture_request(client, "get_request", return_value=[])
 
     client.get_workspace_users()
 
@@ -41,8 +22,8 @@ def test_get_workspace_users_default(monkeypatch, client):
     assert calls[0]["kwargs"]["params"] == {"limit": 20}
 
 
-def test_get_workspace_users_with_params(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "get_request", return_value=[])
+def test_get_workspace_users_with_params(client, capture_request):
+    calls = capture_request(client, "get_request", return_value=[])
 
     client.get_workspace_users(keyword="john", offset=10, limit=50)
 
@@ -53,8 +34,8 @@ def test_get_workspace_users_with_params(monkeypatch, client):
     }
 
 
-def test_get_workspace_users_offset_zero_included(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "get_request", return_value=[])
+def test_get_workspace_users_offset_zero_included(client, capture_request):
+    calls = capture_request(client, "get_request", return_value=[])
 
     client.get_workspace_users(offset=0)
 
@@ -65,8 +46,8 @@ def test_get_workspace_users_offset_zero_included(monkeypatch, client):
 # --- create_workspace_user -------------------------------------------------
 
 
-def test_create_workspace_user_without_modules(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "post_request", return_value={})
+def test_create_workspace_user_without_modules(client, capture_request):
+    calls = capture_request(client, "post_request", return_value={})
 
     client.create_workspace_user(
         name="John Doe",
@@ -87,8 +68,8 @@ def test_create_workspace_user_without_modules(monkeypatch, client):
 # --- update_workspace_user -------------------------------------------------
 
 
-def test_update_workspace_user_role(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "put_request", return_value={})
+def test_update_workspace_user_role(client, capture_request):
+    calls = capture_request(client, "put_request", return_value={})
 
     client.update_workspace_user(email="john@example.com", role="owner")
 
@@ -102,9 +83,9 @@ def test_update_workspace_user_role(monkeypatch, client):
 # --- delete_workspace_user -------------------------------------------------
 
 
-def test_delete_workspace_user(monkeypatch, client):
+def test_delete_workspace_user(client, capture_request):
     # deletion is performed via PUT with role='none' (no DELETE endpoint)
-    calls = _capture(monkeypatch, client, "put_request", return_value=None)
+    calls = capture_request(client, "put_request", return_value=None)
 
     result = client.delete_workspace_user(email="john@example.com")
 
@@ -127,8 +108,10 @@ def test_delete_workspace_user(monkeypatch, client):
         ("modelDev", "function-resource-permissions/model-dev/internal-users"),
     ],
 )
-def test_create_module_permissions_single(monkeypatch, client, module, expected_path):
-    calls = _capture(monkeypatch, client, "post_request", return_value=module)
+def test_create_module_permissions_single(
+    client, capture_request, module, expected_path
+):
+    calls = capture_request(client, "post_request", return_value=module)
 
     # a single module string is accepted (not only a list)
     result = client.create_workspace_user_module_permissions(
@@ -141,8 +124,8 @@ def test_create_module_permissions_single(monkeypatch, client, module, expected_
     assert result == [module]
 
 
-def test_create_module_permissions_multiple(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "post_request", return_value="ok")
+def test_create_module_permissions_multiple(client, capture_request):
+    calls = capture_request(client, "post_request", return_value="ok")
 
     result = client.create_workspace_user_module_permissions(
         email="john@example.com", modules=["annotation", "dataset"]
@@ -156,8 +139,8 @@ def test_create_module_permissions_multiple(monkeypatch, client):
     assert result == ["ok", "ok"]
 
 
-def test_create_module_permissions_invalid_module(monkeypatch, client):
-    _capture(monkeypatch, client, "post_request", return_value=None)
+def test_create_module_permissions_invalid_module(client, capture_request):
+    capture_request(client, "post_request", return_value=None)
 
     with pytest.raises(fastlabel.exceptions.FastLabelInvalidException):
         client.create_workspace_user_module_permissions(
@@ -168,8 +151,8 @@ def test_create_module_permissions_invalid_module(monkeypatch, client):
 # --- delete_workspace_user_module_permissions ------------------------------
 
 
-def test_delete_module_permissions_single(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "delete_request", return_value=None)
+def test_delete_module_permissions_single(client, capture_request):
+    calls = capture_request(client, "delete_request", return_value=None)
 
     client.delete_workspace_user_module_permissions(
         email="john@example.com", modules="modelDev"
@@ -183,8 +166,8 @@ def test_delete_module_permissions_single(monkeypatch, client):
     }
 
 
-def test_delete_module_permissions_multiple(monkeypatch, client):
-    calls = _capture(monkeypatch, client, "delete_request", return_value=None)
+def test_delete_module_permissions_multiple(client, capture_request):
+    calls = capture_request(client, "delete_request", return_value=None)
 
     client.delete_workspace_user_module_permissions(
         email="john@example.com", modules=["annotation", "modelDev"]
@@ -197,8 +180,8 @@ def test_delete_module_permissions_multiple(monkeypatch, client):
     assert all(c["endpoint"] == "function-resource-permissions" for c in calls)
 
 
-def test_delete_module_permissions_invalid_module(monkeypatch, client):
-    _capture(monkeypatch, client, "delete_request", return_value=None)
+def test_delete_module_permissions_invalid_module(client, capture_request):
+    capture_request(client, "delete_request", return_value=None)
 
     with pytest.raises(fastlabel.exceptions.FastLabelInvalidException):
         client.delete_workspace_user_module_permissions(

From 961462de6b2165dd64300fd17d77bb3c1511cf7c Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Wed, 19 Aug 2026 17:07:52 +0900
Subject: [PATCH 07/11] =?UTF-8?q?=E3=82=BB=E3=83=B3=E3=83=81=E3=83=8D?=
 =?UTF-8?q?=E3=83=AB=E3=81=AE=E5=9E=8B=E6=B3=A8=E9=87=88=E3=82=92=E8=AA=BF?=
 =?UTF-8?q?=E6=95=B4=E3=81=97=E3=81=A6=E5=85=AC=E9=96=8B=E3=82=B7=E3=82=B0?=
 =?UTF-8?q?=E3=83=8D=E3=83=81=E3=83=A3=E3=81=8B=E3=82=89=E5=86=85=E9=83=A8?=
 =?UTF-8?q?=E3=82=AF=E3=83=A9=E3=82=B9=E3=82=92=E9=9A=A0=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 fastlabel/__init__.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index 9b6946c..e7b84ba 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -50,7 +50,9 @@ def __repr__(self) -> str:
         return "UNSET"
 
 
-_UNSET = _Unset()
+# Typed as Any so that the marker stays out of the public signatures that use it
+# as their default. Callers only ever pass an int or None.
+_UNSET: Any = _Unset()
 
 
 class Client:
@@ -4311,7 +4313,7 @@ def create_annotation(
         color: str = None,
         order: int = None,
         attributes: list = [],
-        max_area_count: Union[int, None, _Unset] = _UNSET,
+        max_area_count: Optional[int] = _UNSET,
     ) -> str:
         """
         Create an annotation.
@@ -4365,7 +4367,7 @@ def update_annotation(
         color: str = None,
         order: int = None,
         attributes: list = [],
-        max_area_count: Union[int, None, _Unset] = _UNSET,
+        max_area_count: Optional[int] = _UNSET,
     ) -> str:
         """
         Update an annotation.

From f6a5497740a06d09a62b23c6cad90409abc0fda5 Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Fri, 21 Aug 2026 09:45:15 +0900
Subject: [PATCH 08/11] =?UTF-8?q?=E6=9C=AA=E6=8C=87=E5=AE=9A=E3=83=9E?=
 =?UTF-8?q?=E3=83=BC=E3=82=AB=E3=83=BC=E3=82=92=E3=82=B7=E3=83=B3=E3=82=B0?=
 =?UTF-8?q?=E3=83=AB=E3=83=88=E3=83=B3=E3=81=AB=E3=81=97=E3=81=A6=E3=82=B3?=
 =?UTF-8?q?=E3=83=94=E3=83=BC=E3=82=84=E3=82=B7=E3=83=AA=E3=82=A2=E3=83=A9?=
 =?UTF-8?q?=E3=82=A4=E3=82=BA=E3=82=92=E8=B7=A8=E3=81=84=E3=81=A7=E3=82=82?=
 =?UTF-8?q?=E5=90=8C=E4=B8=80=E6=80=A7=E3=81=8C=E4=BF=9D=E3=81=9F=E3=82=8C?=
 =?UTF-8?q?=E3=82=8B=E3=82=88=E3=81=86=E3=81=AB=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

SDKとして公開する都合上、呼び出し側でキーワード引数がdeepcopyやpickleを
経由することがある。素のインスタンスだと同一性比較が壊れ、マーカー自身が
リクエストに載ってしまうため。
---
 fastlabel/__init__.py    | 11 +++++++++++
 tests/test_annotation.py | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index e7b84ba..17ee82f 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -44,8 +44,19 @@ class _Unset:
 
     Needed where None is a meaningful value that has to be sent to the API,
     and therefore cannot double as "leave this field untouched".
+
+    A single shared instance, so that the identity checks that read this marker
+    still hold after it has been copied or serialised on its way through
+    caller code.
     """
 
+    _instance: Optional["_Unset"] = None
+
+    def __new__(cls) -> "_Unset":
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+        return cls._instance
+
     def __repr__(self) -> str:
         return "UNSET"
 
diff --git a/tests/test_annotation.py b/tests/test_annotation.py
index 1396b36..492c18b 100644
--- a/tests/test_annotation.py
+++ b/tests/test_annotation.py
@@ -5,6 +5,13 @@
 (client.api.*_request) is stubbed so no real request is made.
 """
 
+import copy
+import pickle
+
+import pytest
+
+import fastlabel
+
 # --- create_annotation -----------------------------------------------------
 
 
@@ -81,3 +88,32 @@ def test_update_annotation_without_max_area_count_limit(client, capture_request)
 
     # None is sent as an explicit null, which means no limit on the server side
     assert calls[0]["kwargs"]["payload"] == {"maxAreaCount": None}
+
+
+# --- the "not passed" marker -----------------------------------------------
+
+
+@pytest.mark.parametrize(
+    "round_trip",
+    [copy.deepcopy, lambda value: pickle.loads(pickle.dumps(value))],
+    ids=["deepcopy", "pickle"],
+)
+def test_create_annotation_keeps_marker_meaning_after_round_trip(
+    client, capture_request, round_trip
+):
+    calls = capture_request(client, "post_request", return_value="anno-id")
+
+    # Callers that collect keyword arguments and pass them around must still
+    # get "omitted" out of the default, which relies on the marker's identity
+    kwargs = round_trip(
+        {
+            "project": "my-project",
+            "type": "segmentation",
+            "value": "cat",
+            "title": "Cat",
+            "max_area_count": fastlabel._UNSET,
+        }
+    )
+    client.create_annotation(**kwargs)
+
+    assert "maxAreaCount" not in calls[0]["kwargs"]["payload"]

From a990f6b280851091823326990953b0f9ea8a7f37 Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Fri, 21 Aug 2026 09:46:12 +0900
Subject: [PATCH 09/11] =?UTF-8?q?=E6=9C=AA=E6=8C=87=E5=AE=9A=E3=83=9E?=
 =?UTF-8?q?=E3=83=BC=E3=82=AB=E3=83=BC=E3=82=92=E4=BD=BF=E3=81=86=E7=90=86?=
 =?UTF-8?q?=E7=94=B1=E3=82=92=E5=91=BC=E3=81=B3=E5=87=BA=E3=81=97=E7=AE=87?=
 =?UTF-8?q?=E6=89=80=E3=81=A8=E3=83=9E=E3=83=BC=E3=82=AB=E3=83=BC=E5=AE=9A?=
 =?UTF-8?q?=E7=BE=A9=E3=81=AB=E3=82=B3=E3=83=A1=E3=83=B3=E3=83=88=E3=81=A7?=
 =?UTF-8?q?=E6=9B=B8=E3=81=84=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

省略時はNoneという二値の慣習に対して、この項目はnull自体がAPIの受け付ける
値になるため三値になる。慣習との違いが読み手に伝わらずレビューで疑問が
出たため、マーカーの定義側と使用箇所の双方に意図を残す。
---
 fastlabel/__init__.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index 17ee82f..9097c34 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -42,8 +42,12 @@
 class _Unset:
     """Marker for arguments the caller did not pass.
 
-    Needed where None is a meaningful value that has to be sent to the API,
-    and therefore cannot double as "leave this field untouched".
+    Most optional arguments here have two states, and None covers the second
+    one: the field is either sent or left out. A few fields have three, because
+    null is one of the values the API acts on -- left out, sent as null, sent
+    as a value. For those, None is taken up by the null that has to reach the
+    API and cannot also mean "the caller said nothing", so this marker carries
+    that state instead and the argument is read by identity rather than truth.
 
     A single shared instance, so that the identity checks that read this marker
     still hold after it has been copied or serialised on its way through
@@ -4355,6 +4359,9 @@ def create_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
+        # Three states, so the argument is read by identity: left out keeps the
+        # API's own default, None removes the limit, an int sets it. None is a
+        # value the API acts on and cannot also mean "not passed".
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.post_request(endpoint, payload=payload)
@@ -4405,6 +4412,9 @@ def update_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
+        # Three states, so the argument is read by identity: left out keeps the
+        # stored value, None removes the limit, an int sets it. None is a value
+        # the API acts on and cannot also mean "not passed".
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.put_request(endpoint, payload=payload)

From 8b77875272e04775ef4c7de772fb1d3f2cb29d4e Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Fri, 21 Aug 2026 11:24:01 +0900
Subject: [PATCH 10/11] =?UTF-8?q?=E3=82=A2=E3=83=8E=E3=83=86=E3=83=BC?=
 =?UTF-8?q?=E3=82=B7=E3=83=A7=E3=83=B3=E3=82=AF=E3=83=A9=E3=82=B9=E3=81=AE?=
 =?UTF-8?q?=E9=A0=98=E5=9F=9F=E6=95=B0=E4=B8=8A=E9=99=90=20=E6=9C=AA?=
 =?UTF-8?q?=E6=8C=87=E5=AE=9A=E3=83=9E=E3=83=BC=E3=82=AB=E3=83=BC=E3=81=AE?=
 =?UTF-8?q?=E6=84=8F=E5=9B=B3=E3=82=92=E6=97=A5=E6=9C=AC=E8=AA=9E=E3=81=A7?=
 =?UTF-8?q?=E5=85=B7=E4=BD=93=E7=9A=84=E3=81=AB=E6=9B=B8=E3=81=8D=E7=9B=B4?=
 =?UTF-8?q?=E3=81=97=E3=81=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

maxAreaCount は API 側で無制限を null で表すため None が「未指定」を兼ねられず
三値になるという理由を、対象フィールド名と API 仕様を名指しする形で明記した。
従来の英語かつ一般化した説明では、レビューで意図が確認できなかったため。

https://github.com/fastlabel/fastlabel-python-sdk/pull/288#discussion_r3826774760
---
 fastlabel/__init__.py | 41 +++++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index 9097c34..36074db 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -40,18 +40,17 @@
 
 
 class _Unset:
-    """Marker for arguments the caller did not pass.
-
-    Most optional arguments here have two states, and None covers the second
-    one: the field is either sent or left out. A few fields have three, because
-    null is one of the values the API acts on -- left out, sent as null, sent
-    as a value. For those, None is taken up by the null that has to reach the
-    API and cannot also mean "the caller said nothing", so this marker carries
-    that state instead and the argument is read by identity rather than truth.
-
-    A single shared instance, so that the identity checks that read this marker
-    still hold after it has been copied or serialised on its way through
-    caller code.
+    """呼び出し側が引数を渡さなかったことを表すマーカー。
+
+    このモジュールの任意引数は大半が「送る / 送らない」の二値で、後者を None
+    が兼ねられる。一方、null 自体が API へ送る意味のある値になる引数 (領域数
+    上限 maxAreaCount は 0 ではなく null が「無制限」を表す) は「省略 / null /
+    値」の三値になる。この場合 None は API へ届ける null の側に取られるため
+    「呼び出し側が何も言わなかった」を表せず、その状態をこのマーカーが担う。
+    引数は真偽ではなく同一性 (``is``) で判定する。
+
+    インスタンスは 1 つだけ共有する。呼び出し側のコードで copy やシリアライズ
+    を経ても、このマーカーを読む同一性比較が壊れないようにするため。
     """
 
     _instance: Optional["_Unset"] = None
@@ -65,8 +64,8 @@ def __repr__(self) -> str:
         return "UNSET"
 
 
-# Typed as Any so that the marker stays out of the public signatures that use it
-# as their default. Callers only ever pass an int or None.
+# 既定値としてこのマーカーを使う関数の公開シグネチャに内部クラスが露出しない
+# よう Any で注釈する。呼び出し側が実際に渡すのは int か None のみ。
 _UNSET: Any = _Unset()
 
 
@@ -4359,9 +4358,10 @@ def create_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        # Three states, so the argument is read by identity: left out keeps the
-        # API's own default, None removes the limit, an int sets it. None is a
-        # value the API acts on and cannot also mean "not passed".
+        # maxAreaCount は API 側で「無制限」を null で表すため、None を渡すこと
+        # 自体が意味のある操作になる。他の任意引数のように None を「未指定」に
+        # 流用できず、省略 (API 既定値のまま) / None (無制限) / int (上限値) の
+        # 三値になるので、_UNSET との同一性比較で省略かどうかを見分ける。
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.post_request(endpoint, payload=payload)
@@ -4412,9 +4412,10 @@ def update_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        # Three states, so the argument is read by identity: left out keeps the
-        # stored value, None removes the limit, an int sets it. None is a value
-        # the API acts on and cannot also mean "not passed".
+        # maxAreaCount は API 側で「無制限」を null で表すため、None を渡すこと
+        # 自体が意味のある操作になる。他の任意引数のように None を「未指定」に
+        # 流用できず、省略 (保存済みの値のまま) / None (無制限) / int (上限値)
+        # の三値になるので、_UNSET との同一性比較で省略かどうかを見分ける。
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.put_request(endpoint, payload=payload)

From fb6b53d384abb8b948bb469137582893a93141d3 Mon Sep 17 00:00:00 2001
From: soymd <pacificstate33@gmail.com>
Date: Fri, 21 Aug 2026 13:45:25 +0900
Subject: [PATCH 11/11] =?UTF-8?q?=E3=82=A2=E3=83=8E=E3=83=86=E3=83=BC?=
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SDK 全体のコメントが英語で統一されているため、日本語化した分を戻した。
maxAreaCount を名指しし null が無制限を表すという API 仕様を書く具体度は
そのまま英語で維持した。

https://github.com/fastlabel/fastlabel-python-sdk/pull/288#discussion_r3827317862
---
 fastlabel/__init__.py | 46 +++++++++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 21 deletions(-)

diff --git a/fastlabel/__init__.py b/fastlabel/__init__.py
index 36074db..11e40dd 100644
--- a/fastlabel/__init__.py
+++ b/fastlabel/__init__.py
@@ -40,17 +40,19 @@
 
 
 class _Unset:
-    """呼び出し側が引数を渡さなかったことを表すマーカー。
-
-    このモジュールの任意引数は大半が「送る / 送らない」の二値で、後者を None
-    が兼ねられる。一方、null 自体が API へ送る意味のある値になる引数 (領域数
-    上限 maxAreaCount は 0 ではなく null が「無制限」を表す) は「省略 / null /
-    値」の三値になる。この場合 None は API へ届ける null の側に取られるため
-    「呼び出し側が何も言わなかった」を表せず、その状態をこのマーカーが担う。
-    引数は真偽ではなく同一性 (``is``) で判定する。
-
-    インスタンスは 1 つだけ共有する。呼び出し側のコードで copy やシリアライズ
-    を経ても、このマーカーを読む同一性比較が壊れないようにするため。
+    """Marker for arguments the caller did not pass.
+
+    Most optional arguments here have two states and None covers the second
+    one: the field is either sent or left out. maxAreaCount has three, because
+    the API represents "unlimited" as null rather than as 0, so null is itself
+    a value that has to reach the API -- left out, sent as null, sent as a
+    number. None is taken up by that null and cannot also mean "the caller
+    said nothing", so this marker carries that state instead and the argument
+    is read by identity rather than by truthiness.
+
+    A single shared instance, so that the identity checks that read this
+    marker still hold after it has been copied or serialised on its way
+    through caller code.
     """
 
     _instance: Optional["_Unset"] = None
@@ -64,8 +66,8 @@ def __repr__(self) -> str:
         return "UNSET"
 
 
-# 既定値としてこのマーカーを使う関数の公開シグネチャに内部クラスが露出しない
-# よう Any で注釈する。呼び出し側が実際に渡すのは int か None のみ。
+# Typed as Any so that the marker stays out of the public signatures that use it
+# as their default. Callers only ever pass an int or None.
 _UNSET: Any = _Unset()
 
 
@@ -4358,10 +4360,11 @@ def create_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        # maxAreaCount は API 側で「無制限」を null で表すため、None を渡すこと
-        # 自体が意味のある操作になる。他の任意引数のように None を「未指定」に
-        # 流用できず、省略 (API 既定値のまま) / None (無制限) / int (上限値) の
-        # 三値になるので、_UNSET との同一性比較で省略かどうかを見分ける。
+        # maxAreaCount represents "unlimited" as null rather than as 0, so
+        # passing None is itself a meaningful call and None cannot double as
+        # "not passed" the way it does for the other optional arguments. The
+        # three states are read by identity: left out keeps the API's default,
+        # None removes the limit, an int sets it.
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.post_request(endpoint, payload=payload)
@@ -4412,10 +4415,11 @@ def update_annotation(
             payload["order"] = order
         if attributes:
             payload["attributes"] = attributes
-        # maxAreaCount は API 側で「無制限」を null で表すため、None を渡すこと
-        # 自体が意味のある操作になる。他の任意引数のように None を「未指定」に
-        # 流用できず、省略 (保存済みの値のまま) / None (無制限) / int (上限値)
-        # の三値になるので、_UNSET との同一性比較で省略かどうかを見分ける。
+        # maxAreaCount represents "unlimited" as null rather than as 0, so
+        # passing None is itself a meaningful call and None cannot double as
+        # "not passed" the way it does for the other optional arguments. The
+        # three states are read by identity: left out keeps the stored value,
+        # None removes the limit, an int sets it.
         if max_area_count is not _UNSET:
             payload["maxAreaCount"] = max_area_count
         return self.api.put_request(endpoint, payload=payload)