diff --git a/litellm/types/router.py b/litellm/types/router.py
index f3703f82711..c8a53f3467b 100644
--- a/litellm/types/router.py
+++ b/litellm/types/router.py
@@ -357,7 +357,7 @@ class GenericLiteLLMParams(CredentialLiteLLMParams, CustomPricingLiteLLMParams):
     )
     model_config = ConfigDict(extra="allow", arbitrary_types_allowed=True)
     merge_reasoning_content_in_choices: bool | None = False
-    forward_reasoning_content: bool | None = False
+    forward_reasoning_content: bool | None = None
     reasoning_content_field: Literal["reasoning_content", "reasoning"] | None = None
     model_info: dict | None = None
     mock_response: str | ModelResponse | Exception | Any | None = None
diff --git a/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
index 86bbd0d3b4b..ba7bfdcdc21 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_model_management_endpoints.py
@@ -1169,7 +1169,8 @@ class TestUpdateModel:
 
     @pytest.mark.asyncio
     @pytest.mark.parametrize("reasoning_field", [None, "reasoning_content", "reasoning"])
-    async def test_update_model_clears_cache_after_db_write(self, reasoning_field):
+    @pytest.mark.parametrize("forward", [None, False, True])
+    async def test_update_model_clears_cache_after_db_write(self, reasoning_field, forward):
         """
         Regression test for the stale-router bug: POST /model/update must refresh
         the in-memory router after persisting to LiteLLM_ProxyModelTable, otherwise
@@ -1192,6 +1193,7 @@ class TestUpdateModel:
             "model": "openai/gpt-4o-mini",
             "api_key": "sk-existing",
             "reasoning_content_field": "reasoning",
+            "forward_reasoning_content": True,
         }
         existing_row.model_dump.return_value = {
             "model_name": "gpt-4o-mini",
@@ -1239,7 +1241,11 @@ class TestUpdateModel:
         ):
             await update_model(
                 model_params=updateDeployment(
-                    litellm_params=updateLiteLLMParams(guardrails=["g1"], **({} if reasoning_field is None else {"reasoning_content_field": reasoning_field})),
+                    litellm_params=updateLiteLLMParams(
+                        **({"guardrails": ["g1"]} if reasoning_field is None and forward is None else {}),
+                        **({} if reasoning_field is None else {"reasoning_content_field": reasoning_field}),
+                        **({} if forward is None else {"forward_reasoning_content": forward}),
+                    ),
                     model_info=ModelInfo(id=model_id),
                 ),
                 user_api_key_dict=admin_user,
@@ -1249,6 +1255,7 @@ class TestUpdateModel:
             mock_clear_cache.assert_awaited_once_with()
             stored = json.loads(mock_prisma.db.litellm_proxymodeltable.update.call_args.kwargs["data"]["litellm_params"])
             assert stored["reasoning_content_field"] == (reasoning_field or "reasoning")
+            assert stored["forward_reasoning_content"] is (True if forward is None else forward)
 
 
 class TestUpdatePublicModelGroups:
@@ -6205,24 +6212,34 @@ class TestAccessGroupModelSync:
 
 
 @pytest.mark.parametrize("field", [None, "reasoning_content", "reasoning"])
-def test_model_patch_preserves_reasoning_field_unless_explicit(field, monkeypatch):
+@pytest.mark.parametrize("forward", [None, False, True])
+def test_model_patch_preserves_reasoning_field_unless_explicit(field, forward, monkeypatch):
     from litellm.proxy.common_utils.encrypt_decrypt_utils import decrypt_value_helper
     from litellm.proxy.management_endpoints.model_management_endpoints import update_db_model
 
     monkeypatch.setenv("LITELLM_SALT_KEY", "sk-test-reasoning-field")
     deployment = Deployment(
         model_name="reasoning-test",
-        litellm_params=LiteLLM_Params(model="openai/reasoning-test", reasoning_content_field="reasoning"),
+        litellm_params=LiteLLM_Params(model="openai/reasoning-test", reasoning_content_field="reasoning", forward_reasoning_content=True),
         model_info=ModelInfo(id="reasoning-row"),
     )
-    params = updateLiteLLMParams(tpm=123, **({} if field is None else {"reasoning_content_field": field}))
+    params = updateLiteLLMParams(
+        **({"tpm": 123} if field is None and forward is None else {}),
+        **({} if field is None else {"reasoning_content_field": field}),
+        **({} if forward is None else {"forward_reasoning_content": forward}),
+    )
+    if forward is None:
+        assert "forward_reasoning_content" not in params.model_dump(exclude_none=True)
     if field is None:
         assert "reasoning_content_field" not in params.model_dump(exclude_none=True)
     result = update_db_model(db_model=deployment, updated_patch=updateDeployment(litellm_params=params))
     stored = json.loads(result["litellm_params"])
-    assert stored["tpm"] == 123
+    if field is None and forward is None:
+        assert stored["tpm"] == 123
+    assert stored["forward_reasoning_content"] is (True if forward is None else forward)
     assert (
         stored["reasoning_content_field"] if field is None
         else decrypt_value_helper(value=stored["reasoning_content_field"], key="reasoning_content_field")
     ) == (field or "reasoning")
     assert deployment.litellm_params.reasoning_content_field == "reasoning"
+    assert deployment.litellm_params.forward_reasoning_content is True
diff --git a/ui/litellm-dashboard/src/lib/http/schema.d.ts b/ui/litellm-dashboard/src/lib/http/schema.d.ts
index f0df54706b8..a90fce927ca 100644
--- a/ui/litellm-dashboard/src/lib/http/schema.d.ts
+++ b/ui/litellm-dashboard/src/lib/http/schema.d.ts
@@ -29711,11 +29711,8 @@ export interface components {
             default_api_key_tpm_limit?: number | null;
             /** Drop Params */
             drop_params?: boolean | string | null;
-            /**
-             * Forward Reasoning Content
-             * @default false
-             */
-            forward_reasoning_content: boolean | null;
+            /** Forward Reasoning Content */
+            forward_reasoning_content?: boolean | null;
             /** Gcs Bucket Name */
             gcs_bucket_name?: string | null;
             /** Google Maps Grounding Cost Per Query */
@@ -39932,11 +39929,8 @@ export interface components {
             default_api_key_tpm_limit?: number | null;
             /** Drop Params */
             drop_params?: boolean | string | null;
-            /**
-             * Forward Reasoning Content
-             * @default false
-             */
-            forward_reasoning_content: boolean | null;
+            /** Forward Reasoning Content */
+            forward_reasoning_content?: boolean | null;
             /** Gcs Bucket Name */
             gcs_bucket_name?: string | null;
             /** Google Maps Grounding Cost Per Query */