diff --git a/litellm/proxy/auth/auth_utils.py b/litellm/proxy/auth/auth_utils.py
index 39e858240ef..33df65af085 100644
--- a/litellm/proxy/auth/auth_utils.py
+++ b/litellm/proxy/auth/auth_utils.py
@@ -389,10 +389,6 @@ def _build_banned_observability_params() -> frozenset[str]:
     )
 
 
-# Credential selectors that name an account stored on the proxy host, so no
-# client-side opt-in can hand them to a caller. Only the deployment config sets them.
-_OPERATOR_ONLY_REQUEST_BODY_PARAMS: Final[tuple[str, ...]] = ("xai_oauth_token_file",)
-
 _BANNED_REQUEST_BODY_PARAMS: Final[tuple[str, ...]] = (
     "api_base",
     "base_url",
@@ -417,7 +413,6 @@ _BANNED_REQUEST_BODY_PARAMS: Final[tuple[str, ...]] = (
     # caller-supplied value is the same exfil shape as
     # ``aws_web_identity_token`` on the Bedrock path.
     "azure_ad_token",
-    *_OPERATOR_ONLY_REQUEST_BODY_PARAMS,
     # Endpoint-targeting fields that retarget the outbound request or
     # an observability callback. An attacker-controlled value either
     # exfiltrates the request payload (incl. messages + admin-set
@@ -471,6 +466,8 @@ _BANNED_REQUEST_BODY_PARAMS: Final[tuple[str, ...]] = (
     "github_copilot_host",
     "user_provider_credentials",
     "github_copilot_user_session",
+    # Picks which xAI OAuth account stored on the proxy host signs the call.
+    "xai_oauth_token_file",
     # Observability credentials, hosts, and project identifiers: derived
     # from the canonical ``_supported_callback_params`` allowlist so new
     # integrations are covered automatically. Sorted for stable iteration
@@ -502,12 +499,6 @@ def _check_banned_params(
     reject_server_owned_wif_params(wif_body)
     if not manages_deployments:
         reject_federated_credential_reference(body)
-    operator_only: Final = next((param for param in _OPERATOR_ONLY_REQUEST_BODY_PARAMS if param in body), None)
-    if operator_only is not None:
-        raise ValueError(
-            f"Rejected Request: {operator_only} is not allowed in request body. "
-            "Set it on the deployment's litellm_params in your proxy config.yaml instead."
-        )
     for param in _BANNED_REQUEST_BODY_PARAMS:
         if param not in body:
             continue
diff --git a/litellm/types/utils.py b/litellm/types/utils.py
index 5939a350970..71185541258 100644
--- a/litellm/types/utils.py
+++ b/litellm/types/utils.py
@@ -4323,11 +4323,13 @@ def credential_api_key_secret_reference(credential_values: Mapping[str, object])
     return {**credential_values, "api_key": reference}
 
 
+xai_oauth_litellm_params: Final = ("xai_oauth_token_file",)
 server_owned_wif_litellm_params: Final = (
     anthropic_wif_litellm_params
     + openai_wif_litellm_params
     + oauth_token_exchange_litellm_params
     + github_copilot_oauth_litellm_params
+    + xai_oauth_litellm_params
 )
 secret_bearing_wif_litellm_params: Final = tuple(sorted(WIF_SECRET_BEARING_KEYS))
 
diff --git a/tests/unit/proxy/auth/test_auth_utils.py b/tests/unit/proxy/auth/test_auth_utils.py
index 6adead36301..197efe26883 100644
--- a/tests/unit/proxy/auth/test_auth_utils.py
+++ b/tests/unit/proxy/auth/test_auth_utils.py
@@ -5316,6 +5316,7 @@ class TestIsRequestBodySafeBlocksXaiOauthTokenFile:
             {"model": "grok-4", "extra_body": {"xai_oauth_token_file": "auth-bob.json"}},
             {"model": "grok-4", "metadata": {"xai_oauth_token_file": "auth-bob.json"}},
             {"model": "grok-4", "fallbacks": [{"model": "grok-4", "xai_oauth_token_file": "auth-bob.json"}]},
+            {"model": "grok-4", "litellm_params": {"xai_oauth_token_file": "auth-bob.json"}},
         ],
     )
     def test_rejected_even_under_proxy_wide_opt_in(self, request_body):
@@ -5327,6 +5328,12 @@ class TestIsRequestBodySafeBlocksXaiOauthTokenFile:
                 model="grok-4",
             )
 
+    def test_rejected_in_stored_fallback_targets_and_health_check_params(self):
+        from litellm.proxy.auth.auth_utils import reject_server_owned_wif_params
+
+        with pytest.raises(ValueError, match="xai_oauth_token_file"):
+            reject_server_owned_wif_params({"model": "xai/grok-4", "xai_oauth_token_file": "auth-bob.json"})
+
     def test_rejected_even_when_deployment_lists_it_as_clientside_configurable(self):
         from litellm import Router
 
diff --git a/tests/unit/proxy/auth/test_banned_params_extra_body.py b/tests/unit/proxy/auth/test_banned_params_extra_body.py
index 6c621b03cba..e87b206a40a 100644
--- a/tests/unit/proxy/auth/test_banned_params_extra_body.py
+++ b/tests/unit/proxy/auth/test_banned_params_extra_body.py
@@ -28,7 +28,6 @@ from litellm.proxy.auth.auth_utils import is_request_body_safe  # noqa: E402
         "base_url",
         "vertex_credentials",
         "azure_ad_token",
-        "xai_oauth_token_file",
     ],
 )
 def test_banned_param_under_extra_body_is_rejected(banned_param):
diff --git a/tests/unit/proxy/management_endpoints/test_model_management_endpoints.py b/tests/unit/proxy/management_endpoints/test_model_management_endpoints.py
index 303b8e060ed..7316decb188 100644
--- a/tests/unit/proxy/management_endpoints/test_model_management_endpoints.py
+++ b/tests/unit/proxy/management_endpoints/test_model_management_endpoints.py
@@ -8989,14 +8989,21 @@ class TestNonAdminCannotPersistWifFieldsOnModel:
             mock_prisma.db.litellm_proxymodeltable.update.assert_not_called()
 
     @pytest.mark.asyncio
-    async def test_patch_model_non_admin_cannot_set_openai_wif_field(self):
+    @pytest.mark.parametrize(
+        ("model", "field", "value"),
+        [
+            ("openai/gpt-4o-mini", "openai_identity_token_file", "/var/run/secrets/tokens/attacker"),
+            ("xai/grok-4", "xai_oauth_token_file", "auth-other-account.json"),
+        ],
+    )
+    async def test_patch_model_non_admin_cannot_set_server_owned_token_file(self, model: str, field: str, value: str):
         from litellm.proxy.management_endpoints.model_management_endpoints import (
             patch_model,
         )
 
         non_admin = UserAPIKeyAuth(user_id="team_admin", user_role=LitellmUserRoles.INTERNAL_USER)
         existing_row = MagicMock()
-        existing_row.litellm_params = {"model": "openai/gpt-4o-mini"}
+        existing_row.litellm_params = {"model": model}
         existing_row.model_dump.return_value = {
             "model_name": "gpt",
             "litellm_params": existing_row.litellm_params,
@@ -9033,14 +9040,10 @@ class TestNonAdminCannotPersistWifFieldsOnModel:
             ) as exc_info:
                 await patch_model(
                     model_id="m1",
-                    patch_data=updateDeployment(
-                        litellm_params=updateLiteLLMParams(
-                            openai_identity_token_file="/var/run/secrets/tokens/attacker",
-                        )
-                    ),
+                    patch_data=updateDeployment(litellm_params=updateLiteLLMParams.model_validate({field: value})),
                     user_api_key_dict=non_admin,
                 )
-            assert getattr(exc_info.value, "param", "") == "openai_identity_token_file"
+            assert getattr(exc_info.value, "param", "") == field
             mock_prisma.db.litellm_proxymodeltable.update.assert_not_called()
 
     @pytest.mark.asyncio
diff --git a/tests/unit/types/test_router.py b/tests/unit/types/test_router.py
index 2892a829eab..430d06998cd 100644
--- a/tests/unit/types/test_router.py
+++ b/tests/unit/types/test_router.py
@@ -27,6 +27,7 @@ from litellm.types.utils import (
     oauth_token_exchange_litellm_params,
     openai_wif_litellm_params,
     server_owned_wif_litellm_params,
+    xai_oauth_litellm_params,
 )
 
 
@@ -367,6 +368,7 @@ def test_server_owned_registry_includes_anthropic_openai_and_oauth_token_exchang
         + openai_wif_litellm_params
         + oauth_token_exchange_litellm_params
         + github_copilot_oauth_litellm_params
+        + xai_oauth_litellm_params
     )
     assert set(openai_wif_litellm_params) == {
         "openai_identity_provider_id",