diff --git a/litellm/llms/azure_ai/azure_model_router/transformation.py b/litellm/llms/azure_ai/azure_model_router/transformation.py
index d33564c0f9a..61cbc213b11 100644
--- a/litellm/llms/azure_ai/azure_model_router/transformation.py
+++ b/litellm/llms/azure_ai/azure_model_router/transformation.py
@@ -99,7 +99,7 @@ class AzureModelRouterConfig(AzureAIStudioConfig):
         if selected_model:
             # Rebuilt rather than mutated in place: ModelResponseBase declares _hidden_params as a
             # class-level dict, so an in-place write can bleed into unrelated responses.
-            transformed_response._hidden_params = {  # pyright: ignore[reportPrivateUsage]  # ModelResponse exposes no public hidden-params setter
+            transformed_response._hidden_params = {  # pyright: ignore[reportPrivateUsage]  # ModelResponse exposes no public hidden-params setter  # mutable-ok: ModelResponse requires _hidden_params to be a plain dict
                 **get_hidden_params_dict(transformed_response),
                 AZURE_MODEL_ROUTER_SELECTED_MODEL_KEY: selected_model,
             }
diff --git a/litellm/llms/azure_ai/common_utils.py b/litellm/llms/azure_ai/common_utils.py
index e8431f29f07..55a51176666 100644
--- a/litellm/llms/azure_ai/common_utils.py
+++ b/litellm/llms/azure_ai/common_utils.py
@@ -112,7 +112,11 @@ class AzureFoundryModelInfo(BaseLLMModelInfo):
         """
         if AzureFoundryModelInfo.get_model_router_selected_model(hidden_params) is not None:
             return True
-        deployment_model: Final = (hidden_params or {}).get("litellm_model_name") or (hidden_params or {}).get("model")
+        deployment_model: Final = (
+            hidden_params.get("litellm_model_name") or hidden_params.get("model")
+            if hidden_params is not None
+            else None
+        )
         return any(
             isinstance(candidate, str) and AzureFoundryModelInfo.get_azure_ai_route(candidate) == "model_router"
             for candidate in (deployment_model, model)