diff --git a/backend/magic_plan/audit_script.py b/backend/magic_plan/audit_script.py
new file mode 100644
index 00000000..e418b712
--- /dev/null
+++ b/backend/magic_plan/audit_script.py
@@ -0,0 +1,25 @@
+from dataclasses import dataclass
+from typing import Optional
+
+from datatypes.magicplan.domain.models import Plan
+
+
+@dataclass
+class AuditRow:
+    floor_level: Optional[int] = None  # set only on floor-separator rows
+    room_name: Optional[str] = None
+    room_width_m: Optional[float] = None
+    room_length_m: Optional[float] = None
+    room_area_m2: Optional[float] = None
+    window_label: Optional[str] = None
+    window_location: Optional[str] = None
+    window_width_m: Optional[float] = None
+    window_height_m: Optional[float] = None
+    window_area_m2: Optional[float] = None
+    window_opening_type: Optional[str] = None
+    door_location: Optional[str] = None
+    door_width_mm: Optional[float] = None
+
+
+def _build_rows(plan: Plan) -> list[AuditRow]:
+    raise NotImplementedError
diff --git a/backend/magic_plan/tests/test_audit_script.py b/backend/magic_plan/tests/test_audit_script.py
new file mode 100644
index 00000000..9c39edb6
--- /dev/null
+++ b/backend/magic_plan/tests/test_audit_script.py
@@ -0,0 +1,13 @@
+from datatypes.magicplan.domain.models import Door, Floor, Plan, Room, Window
+from backend.magic_plan.audit_script import AuditRow, _build_rows
+
+
+def test_build_rows_empty_plan_returns_empty_list() -> None:
+    # Arrange
+    plan = Plan(uid="x", name=None, floors=[])
+
+    # Act
+    rows: list[AuditRow] = _build_rows(plan)
+
+    # Assert
+    assert rows == []