diff --git a/docs/examples/data_transfer_objects/factory/marking_fields.py b/docs/examples/data_transfer_objects/factory/marking_fields.py
index 7649f2f8b5..0574273c3f 100644
--- a/docs/examples/data_transfer_objects/factory/marking_fields.py
+++ b/docs/examples/data_transfer_objects/factory/marking_fields.py
@@ -10,6 +10,8 @@
 
 
 class User(Base):
+    # `Base` defines `id` field as:
+    # id: Mapped[UUID] = mapped_column(default=uuid4, primary_key=True)
     name: Mapped[str]
     password: Mapped[str] = mapped_column(info=dto_field("private"))
     created_at: Mapped[datetime] = mapped_column(info=dto_field("read-only"))
@@ -20,6 +22,9 @@ class User(Base):
 
 @post("/users", dto=UserDTO, sync_to_thread=False)
 def create_user(data: User) -> User:
+    # even though the client did not send the id field,
+    # since it is a primary key it is autogenerated
+    assert "id" in vars(data)
     # even though the client sent the password and created_at field, it is not in the data object
     assert "password" not in vars(data)
     assert "created_at" not in vars(data)
diff --git a/docs/examples/data_transfer_objects/factory/simple_dto_factory_example.py b/docs/examples/data_transfer_objects/factory/simple_dto_factory_example.py
index 0bcf7fd184..88f78beb16 100644
--- a/docs/examples/data_transfer_objects/factory/simple_dto_factory_example.py
+++ b/docs/examples/data_transfer_objects/factory/simple_dto_factory_example.py
@@ -9,6 +9,8 @@
 
 
 class User(Base):
+    # `Base` defines `id` field as:
+    # id: Mapped[UUID] = mapped_column(default=uuid4, primary_key=True)
     name: Mapped[str]
     password: Mapped[str]
     created_at: Mapped[datetime]
diff --git a/docs/usage/dto/1-abstract-dto.rst b/docs/usage/dto/1-abstract-dto.rst
index 5c8d8995d9..a39f583ef2 100644
--- a/docs/usage/dto/1-abstract-dto.rst
+++ b/docs/usage/dto/1-abstract-dto.rst
@@ -50,6 +50,8 @@ Fields marked as ``"private"`` or ``"read-only"`` will not be parsed from client
     :emphasize-lines: 6,14,15
     :linenos:
 
+Note that ``id`` field is the primary key and is handled specially by the defined SQLAlchemy base.
+
 .. note:
 
     The procedure for "marking" a model field will vary depending on the library. For example,