diff --git a/src/cohere/core/unchecked_base_model.py b/src/cohere/core/unchecked_base_model.py
index 67d7e3be4..ad39f0298 100644
--- a/src/cohere/core/unchecked_base_model.py
+++ b/src/cohere/core/unchecked_base_model.py
@@ -360,7 +360,8 @@ def construct_type(
         if not isinstance(object_, typing.Mapping):
             return object_
 
-        key_type, items_type = get_args(type_)
+        args = get_args(type_)
+        key_type, items_type = args if args else (typing.Any, typing.Any)
         key_type = _maybe_resolve_forward_ref(key_type, host)
         items_type = _maybe_resolve_forward_ref(items_type, host)
         d = {
diff --git a/tests/test_unchecked_base_model.py b/tests/test_unchecked_base_model.py
new file mode 100644
index 000000000..11ae0dae2
--- /dev/null
+++ b/tests/test_unchecked_base_model.py
@@ -0,0 +1,11 @@
+import sys
+import os
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "src"))
+
+from cohere.core.unchecked_base_model import construct_type
+
+
+def test_construct_type_bare_dict_no_unpack_error():
+    # bare dict (unparameterized) must not raise ValueError on get_args unpacking
+    result = construct_type(type_=dict, object_={"key": "value"})
+    assert result == {"key": "value"}