diff --git a/src/metronome/_base_client.py b/src/metronome/_base_client.py
index b6ea919d..57be344f 100644
--- a/src/metronome/_base_client.py
+++ b/src/metronome/_base_client.py
@@ -418,10 +418,17 @@ def _build_headers(self, options: FinalRequestOptions, *, retries_taken: int = 0
         if idempotency_header and options.method.lower() != "get" and idempotency_header not in headers:
             headers[idempotency_header] = options.idempotency_key or self._idempotency_key()
 
-        # Don't set the retry count header if it was already set or removed by the caller. We check
+        # Don't set these headers if they were already set or removed by the caller. We check
         # `custom_headers`, which can contain `Omit()`, instead of `headers` to account for the removal case.
-        if "x-stainless-retry-count" not in (header.lower() for header in custom_headers):
+        lower_custom_headers = [header.lower() for header in custom_headers]
+        if "x-stainless-retry-count" not in lower_custom_headers:
             headers["x-stainless-retry-count"] = str(retries_taken)
+        if "x-stainless-read-timeout" not in lower_custom_headers:
+            timeout = self.timeout if isinstance(options.timeout, NotGiven) else options.timeout
+            if isinstance(timeout, Timeout):
+                timeout = timeout.read
+            if timeout is not None:
+                headers["x-stainless-read-timeout"] = str(timeout)
 
         return headers
 
diff --git a/src/metronome/_models.py b/src/metronome/_models.py
index 12c34b7d..c4401ff8 100644
--- a/src/metronome/_models.py
+++ b/src/metronome/_models.py
@@ -426,10 +426,16 @@ def construct_type(*, value: object, type_: object) -> object:
 
     If the given value does not match the expected type then it is returned as-is.
     """
+
+    # store a reference to the original type we were given before we extract any inner
+    # types so that we can properly resolve forward references in `TypeAliasType` annotations
+    original_type = None
+
     # we allow `object` as the input type because otherwise, passing things like
     # `Literal['value']` will be reported as a type error by type checkers
     type_ = cast("type[object]", type_)
     if is_type_alias_type(type_):
+        original_type = type_  # type: ignore[unreachable]
         type_ = type_.__value__  # type: ignore[unreachable]
 
     # unwrap `Annotated[T, ...]` -> `T`
@@ -446,7 +452,7 @@ def construct_type(*, value: object, type_: object) -> object:
 
     if is_union(origin):
         try:
-            return validate_type(type_=cast("type[object]", type_), value=value)
+            return validate_type(type_=cast("type[object]", original_type or type_), value=value)
         except Exception:
             pass
 
diff --git a/src/metronome/_utils/_transform.py b/src/metronome/_utils/_transform.py
index a6b62cad..18afd9d8 100644
--- a/src/metronome/_utils/_transform.py
+++ b/src/metronome/_utils/_transform.py
@@ -25,7 +25,7 @@
     is_annotated_type,
     strip_annotated_type,
 )
-from .._compat import model_dump, is_typeddict
+from .._compat import get_origin, model_dump, is_typeddict
 
 _T = TypeVar("_T")
 
@@ -164,9 +164,14 @@ def _transform_recursive(
         inner_type = annotation
 
     stripped_type = strip_annotated_type(inner_type)
+    origin = get_origin(stripped_type) or stripped_type
     if is_typeddict(stripped_type) and is_mapping(data):
         return _transform_typeddict(data, stripped_type)
 
+    if origin == dict and is_mapping(data):
+        items_type = get_args(stripped_type)[1]
+        return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
+
     if (
         # List[T]
         (is_list_type(stripped_type) and is_list(data))
@@ -307,9 +312,14 @@ async def _async_transform_recursive(
         inner_type = annotation
 
     stripped_type = strip_annotated_type(inner_type)
+    origin = get_origin(stripped_type) or stripped_type
     if is_typeddict(stripped_type) and is_mapping(data):
         return await _async_transform_typeddict(data, stripped_type)
 
+    if origin == dict and is_mapping(data):
+        items_type = get_args(stripped_type)[1]
+        return {key: _transform_recursive(value, annotation=items_type) for key, value in data.items()}
+
     if (
         # List[T]
         (is_list_type(stripped_type) and is_list(data))
diff --git a/tests/test_transform.py b/tests/test_transform.py
index 993b9092..e506d87b 100644
--- a/tests/test_transform.py
+++ b/tests/test_transform.py
@@ -2,7 +2,7 @@
 
 import io
 import pathlib
-from typing import Any, List, Union, TypeVar, Iterable, Optional, cast
+from typing import Any, Dict, List, Union, TypeVar, Iterable, Optional, cast
 from datetime import date, datetime
 from typing_extensions import Required, Annotated, TypedDict
 
@@ -388,6 +388,15 @@ def my_iter() -> Iterable[Baz8]:
     }
 
 
+@parametrize
+@pytest.mark.asyncio
+async def test_dictionary_items(use_async: bool) -> None:
+    class DictItems(TypedDict):
+        foo_baz: Annotated[str, PropertyInfo(alias="fooBaz")]
+
+    assert await transform({"foo": {"foo_baz": "bar"}}, Dict[str, DictItems], use_async) == {"foo": {"fooBaz": "bar"}}
+
+
 class TypedDictIterableUnionStr(TypedDict):
     foo: Annotated[Union[str, Iterable[Baz8]], PropertyInfo(alias="FOO")]