diff --git a/.stats.yml b/.stats.yml
index c63d10a5..c539f8e1 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,2 +1,2 @@
 configured_endpoints: 41
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/finch%2Ffinch-bdcde3824560a11eb7286deb9068127ac50ca5d2e4036d1400a8feba24f485a8.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/finch%2Ffinch-ca7f774eb91877a7573cadf88c8aa3c26c2e7133ba3855dbca5a434b46c762b5.yml
diff --git a/src/finch/_utils/_sync.py b/src/finch/_utils/_sync.py
index 8b3aaf2b..ad7ec71b 100644
--- a/src/finch/_utils/_sync.py
+++ b/src/finch/_utils/_sync.py
@@ -7,16 +7,20 @@
 from typing import Any, TypeVar, Callable, Awaitable
 from typing_extensions import ParamSpec
 
+import anyio
+import sniffio
+import anyio.to_thread
+
 T_Retval = TypeVar("T_Retval")
 T_ParamSpec = ParamSpec("T_ParamSpec")
 
 
 if sys.version_info >= (3, 9):
-    to_thread = asyncio.to_thread
+    _asyncio_to_thread = asyncio.to_thread
 else:
     # backport of https://docs.python.org/3/library/asyncio-task.html#asyncio.to_thread
     # for Python 3.8 support
-    async def to_thread(
+    async def _asyncio_to_thread(
         func: Callable[T_ParamSpec, T_Retval], /, *args: T_ParamSpec.args, **kwargs: T_ParamSpec.kwargs
     ) -> Any:
         """Asynchronously run function *func* in a separate thread.
@@ -34,6 +38,17 @@ async def to_thread(
         return await loop.run_in_executor(None, func_call)
 
 
+async def to_thread(
+    func: Callable[T_ParamSpec, T_Retval], /, *args: T_ParamSpec.args, **kwargs: T_ParamSpec.kwargs
+) -> T_Retval:
+    if sniffio.current_async_library() == "asyncio":
+        return await _asyncio_to_thread(func, *args, **kwargs)
+
+    return await anyio.to_thread.run_sync(
+        functools.partial(func, *args, **kwargs),
+    )
+
+
 # inspired by `asyncer`, https://github.com/tiangolo/asyncer
 def asyncify(function: Callable[T_ParamSpec, T_Retval]) -> Callable[T_ParamSpec, Awaitable[T_Retval]]:
     """
diff --git a/tests/api_resources/sandbox/test_employment.py b/tests/api_resources/sandbox/test_employment.py
index 677cbc8e..368ae958 100644
--- a/tests/api_resources/sandbox/test_employment.py
+++ b/tests/api_resources/sandbox/test_employment.py
@@ -73,7 +73,7 @@ def test_method_update_with_all_params(self, client: Finch) -> None:
             manager={"id": "id"},
             middle_name="middle_name",
             source_id="source_id",
-            start_date="3/4/2020",
+            start_date="start_date",
             title="title",
         )
         assert_matches_type(EmploymentUpdateResponse, employment, path=["response"])
@@ -169,7 +169,7 @@ async def test_method_update_with_all_params(self, async_client: AsyncFinch) ->
             manager={"id": "id"},
             middle_name="middle_name",
             source_id="source_id",
-            start_date="3/4/2020",
+            start_date="start_date",
             title="title",
         )
         assert_matches_type(EmploymentUpdateResponse, employment, path=["response"])
diff --git a/tests/api_resources/sandbox/test_individual.py b/tests/api_resources/sandbox/test_individual.py
index 1f2e1ca3..23239fc2 100644
--- a/tests/api_resources/sandbox/test_individual.py
+++ b/tests/api_resources/sandbox/test_individual.py
@@ -28,7 +28,7 @@ def test_method_update(self, client: Finch) -> None:
     def test_method_update_with_all_params(self, client: Finch) -> None:
         individual = client.sandbox.individual.update(
             individual_id="individual_id",
-            dob="12/20/1989",
+            dob="dob",
             emails=[
                 {
                     "data": "data",
@@ -108,7 +108,7 @@ async def test_method_update(self, async_client: AsyncFinch) -> None:
     async def test_method_update_with_all_params(self, async_client: AsyncFinch) -> None:
         individual = await async_client.sandbox.individual.update(
             individual_id="individual_id",
-            dob="12/20/1989",
+            dob="dob",
             emails=[
                 {
                     "data": "data",