diff --git a/midcli/command/generic_call/__init__.py b/midcli/command/generic_call/__init__.py
index 0cea71a..52417b4 100644
--- a/midcli/command/generic_call/__init__.py
+++ b/midcli/command/generic_call/__init__.py
@@ -39,7 +39,10 @@ def _process_method(self, method):
     def _create_arguments(self):
         for i, item in enumerate(self.method["accepts"] or []):
             if i == self.splice_kwargs:
-                if "anyOf" in item and all(option.get("type") == "object" for option in item["anyOf"]):
+                # Handle discriminated unions (oneOf with discriminator) and anyOf unions
+                if ("anyOf" in item or "oneOf" in item) and all(
+                    option.get("type") == "object" for option in item.get("anyOf") or item.get("oneOf")
+                ):
                     # FIXME: Remove this when we use proper field discriminators in API
                     item = {"type": "object", "_attrs_order_": []}
 
diff --git a/midcli/gui/base/steps/input_delegate.py b/midcli/gui/base/steps/input_delegate.py
index eb48ec2..63d5253 100644
--- a/midcli/gui/base/steps/input_delegate.py
+++ b/midcli/gui/base/steps/input_delegate.py
@@ -29,7 +29,9 @@ def create_input_delegate(input: "Input", schema: dict) -> "InputDelegate":
                 type.add("null")
             elif isinstance(v, str):
                 type.add("string")
-    elif "anyOf" in schema and (type := {s["type"] for s in schema["anyOf"]}):
+    elif ("anyOf" in schema or "oneOf" in schema) and (
+        type := {s["type"] for s in schema.get("anyOf", []) or schema.get("oneOf", [])}
+    ):
         pass
     else:
         raise ValueError(f"Unable to create input delegate for schema {schema!r}")