diff --git a/src/sophios/api/utils/ict/ict_spec/cast.py b/src/sophios/api/utils/ict/ict_spec/cast.py
index 7225223a..89b2f687 100644
--- a/src/sophios/api/utils/ict/ict_spec/cast.py
+++ b/src/sophios/api/utils/ict/ict_spec/cast.py
@@ -7,23 +7,6 @@
 from sophios.api.utils.ict.ict_spec.model import ICT
 
 
-def remove_invalid_keys(ict_data: dict) -> None:
-    """remove invalid keys from "ui"""
-
-    if ("ui" in ict_data):
-
-        ui_list = ict_data["ui"]
-
-        # ensure ui is correct data type according to ICT schema
-        if (not isinstance(ui_list, list)):
-            raise RuntimeError("Error: ui must be a list in ICT data.")
-
-        # remove incorrect keys
-        for ui in ui_list:
-            ui.pop("format", None)
-            ui.pop("required", None)
-
-
 def cast_to_ict(ict: Union[Path, str, dict]) -> ICT:
 
     if isinstance(ict, str):
@@ -40,10 +23,10 @@ def cast_to_ict(ict: Union[Path, str, dict]) -> ICT:
         else:
             raise ValueError(f"File extension not supported: {ict}")
 
-        remove_invalid_keys(data)
+        data.pop("ui", None)
 
         return ICT(**data)
 
-    remove_invalid_keys(ict)
+    ict.pop("ui", None)
 
     return ICT(**ict)
diff --git a/src/sophios/api/utils/ict/ict_spec/model.py b/src/sophios/api/utils/ict/ict_spec/model.py
index 42609045..bd1c8c01 100644
--- a/src/sophios/api/utils/ict/ict_spec/model.py
+++ b/src/sophios/api/utils/ict/ict_spec/model.py
@@ -24,7 +24,7 @@ class ICT(Metadata):
 
     inputs: list[IO]
     outputs: list[IO]
-    ui: list[UIItem]
+    ui: Optional[list[UIItem]]
     hardware: Optional[HardwareRequirements] = None
 
     @model_validator(mode="after")