diff --git a/smartsim/settings/base.py b/smartsim/settings/base.py
index 680800f8a..262476bc9 100644
--- a/smartsim/settings/base.py
+++ b/smartsim/settings/base.py
@@ -455,13 +455,17 @@ def add_exe_args(self, args: t.Union[str, t.List[str]]) -> None:
         :type args: str | list[str]
         :raises TypeError: if exe args are not strings
         """
+        
+        if not isinstance(args, (list, str)):
+            raise TypeError("All elements in the list should be of type str")
+        
         if isinstance(args, str):
             args = args.split()
 
-        for arg in args:
-            if not isinstance(arg, str):
-                raise TypeError("Executable arguments should be a list of str")
-
+        if isinstance(args, list):
+            if not all(isinstance(arg, str) for arg in args):
+                raise TypeError("All elements in the list should be of type str")
+    
         self._exe_args.extend(args)
 
     def set(
@@ -545,13 +549,6 @@ def _build_exe_args(exe_args: t.Optional[t.Union[str, t.List[str]]]) -> t.List[s
             if isinstance(exe_args, str):
                 return exe_args.split()
             if isinstance(exe_args, list):
-                exe_args = copy.deepcopy(exe_args)
-                nested_type = all(
-                    all(isinstance(arg, (str)) for arg in exe_args_list)
-                    for exe_args_list in exe_args
-                )
-                if not nested_type:
-                    raise TypeError("Executable arguments were not list of str or str")
                 return exe_args
         return []
 
diff --git a/tests/test_run_settings.py b/tests/test_run_settings.py
index 6eb51cb71..eafd43261 100644
--- a/tests/test_run_settings.py
+++ b/tests/test_run_settings.py
@@ -207,10 +207,10 @@ def test_add_exe_args_list_of_mixed_lists_init():
     """Ensure that any non-string exe arg fails validation for all"""
     exe_args = [["1", "2", 3], ["4", "5", 6]]
 
-    with pytest.raises(TypeError) as type_error:
-        settings = RunSettings("python", exe_args=exe_args)
+    with pytest.raises(TypeError)  as type_error:
+        _ = RunSettings("python", exe_args=exe_args)
 
-    assert "Executable arguments should be a list of str" in type_error.value.args
+    assert "Executable arguments were not list of str or str." in type_error.value.args
 
 
 def test_add_exe_args_list_of_str_lists_init():