diff --git a/tests/test_client.py b/tests/test_client.py
index b421541f..0b0b783b 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -23,10 +23,12 @@
 
 from codex import Codex, AsyncCodex, APIResponseValidationError
 from codex._types import Omit
+from codex._utils import maybe_transform
 from codex._models import BaseModel, FinalRequestOptions
 from codex._constants import RAW_RESPONSE_HEADER
 from codex._exceptions import APIStatusError, APITimeoutError, APIResponseValidationError
 from codex._base_client import DEFAULT_TIMEOUT, HTTPX_DEFAULT_TIMEOUT, BaseClient, make_request_options
+from codex.types.project_create_params import ProjectCreateParams
 
 from .utils import update_env
 
@@ -680,7 +682,13 @@ def test_retrying_timeout_errors_doesnt_leak(self, respx_mock: MockRouter) -> No
         with pytest.raises(APITimeoutError):
             self.client.post(
                 "/api/projects/",
-                body=cast(object, dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e")),
+                body=cast(
+                    object,
+                    maybe_transform(
+                        dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e"),
+                        ProjectCreateParams,
+                    ),
+                ),
                 cast_to=httpx.Response,
                 options={"headers": {RAW_RESPONSE_HEADER: "stream"}},
             )
@@ -695,7 +703,13 @@ def test_retrying_status_errors_doesnt_leak(self, respx_mock: MockRouter) -> Non
         with pytest.raises(APIStatusError):
             self.client.post(
                 "/api/projects/",
-                body=cast(object, dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e")),
+                body=cast(
+                    object,
+                    maybe_transform(
+                        dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e"),
+                        ProjectCreateParams,
+                    ),
+                ),
                 cast_to=httpx.Response,
                 options={"headers": {RAW_RESPONSE_HEADER: "stream"}},
             )
@@ -1425,7 +1439,13 @@ async def test_retrying_timeout_errors_doesnt_leak(self, respx_mock: MockRouter)
         with pytest.raises(APITimeoutError):
             await self.client.post(
                 "/api/projects/",
-                body=cast(object, dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e")),
+                body=cast(
+                    object,
+                    maybe_transform(
+                        dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e"),
+                        ProjectCreateParams,
+                    ),
+                ),
                 cast_to=httpx.Response,
                 options={"headers": {RAW_RESPONSE_HEADER: "stream"}},
             )
@@ -1440,7 +1460,13 @@ async def test_retrying_status_errors_doesnt_leak(self, respx_mock: MockRouter)
         with pytest.raises(APIStatusError):
             await self.client.post(
                 "/api/projects/",
-                body=cast(object, dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e")),
+                body=cast(
+                    object,
+                    maybe_transform(
+                        dict(config={}, name="name", organization_id="182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e"),
+                        ProjectCreateParams,
+                    ),
+                ),
                 cast_to=httpx.Response,
                 options={"headers": {RAW_RESPONSE_HEADER: "stream"}},
             )