diff --git a/src/anthropic/_utils/_transform.py b/src/anthropic/_utils/_transform.py
index 1e7e5ac80..cdf59c531 100644
--- a/src/anthropic/_utils/_transform.py
+++ b/src/anthropic/_utils/_transform.py
@@ -180,7 +180,8 @@ def _transform_recursive(
         return _transform_typeddict(data, stripped_type)
 
     if origin == dict and is_mapping(data):
-        items_type = get_args(stripped_type)[1]
+        args = get_args(stripped_type)
+        items_type = args[1] if len(args) >= 2 else Any
         return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
 
     if (
@@ -346,7 +347,8 @@ async def _async_transform_recursive(
         return await _async_transform_typeddict(data, stripped_type)
 
     if origin == dict and is_mapping(data):
-        items_type = get_args(stripped_type)[1]
+        args = get_args(stripped_type)
+        items_type = args[1] if len(args) >= 2 else Any
         return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
 
     if (
diff --git a/tests/test_transform.py b/tests/test_transform.py
index 4a874ff86..a1a2e8a03 100644
--- a/tests/test_transform.py
+++ b/tests/test_transform.py
@@ -458,3 +458,12 @@ async def test_strips_notgiven(use_async: bool) -> None:
 async def test_strips_omit(use_async: bool) -> None:
     assert await transform({"foo_bar": "bar"}, Foo1, use_async) == {"fooBar": "bar"}
     assert await transform({"foo_bar": omit}, Foo1, use_async) == {}
+
+
+@parametrize
+@pytest.mark.asyncio
+async def test_transform_recursive_bare_dict_no_index_error(use_async: bool) -> None:
+    # A bare (unparameterized) `dict` annotation must not raise IndexError when
+    # get_args(dict) returns () and the code tries to index position [1].
+    result = await transform({"key": "value"}, dict, use_async)
+    assert result == {"key": "value"}