fix(router): register model info under responses/-stripped variant

litellm/router.py

@@ -7076,11 +7076,11 @@ def _create_deployment(
             _shared_model_info = {
                 k: v for k, v in _model_info.items() if k not in _custom_pricing_fields
             }
-            litellm.register_model(
-                model_cost={
-                    _model_name: _shared_model_info,
-                }
-            )
+            _backend_alias_cost = {_model_name: _shared_model_info}
+            if "responses/" in _model_name:
+                _stripped_model_name = _model_name.replace("responses/", "")
+                _backend_alias_cost[_stripped_model_name] = _shared_model_info
+            litellm.register_model(model_cost=_backend_alias_cost)
 
             ## Check if LLM Deployment is allowed for this deployment
             if (
@@ -7752,20 +7752,44 @@ def add_deployment(self, deployment: Deployment) -> Optional[Deployment]:
         # initialize client
         self._add_deployment(deployment=deployment)
 
+        _model_info_dict: dict = deployment.model_info.model_dump(exclude_none=True)
+        for field in CustomPricingLiteLLMParams.model_fields.keys():
+            field_value = deployment.litellm_params.get(field)
+            if field_value is not None:
+                _model_info_dict[field] = field_value
+
         # Register custom pricing in litellm.model_cost.
         # Mirrors _create_deployment() logic to ensure dynamically-added deployments
         # (e.g., loaded from DB) also have their custom pricing registered.
         # Without this, _is_model_cost_zero() cannot detect explicitly-configured
         # zero-cost models, causing budget checks to block free models.
         _model_id = deployment.model_info.id
         if _model_id is not None:
-            _model_info_dict: dict = deployment.model_info.model_dump(exclude_none=True)
-            for field in CustomPricingLiteLLMParams.model_fields.keys():
-                field_value = deployment.litellm_params.get(field)
-                if field_value is not None:
-                    _model_info_dict[field] = field_value
             litellm.register_model(model_cost={_model_id: _model_info_dict})
 
+        ## REGISTER MODEL INFO IN LITELLM MODEL COST MAP
+        ## OLD MODEL REGISTRATION ## Kept to prevent breaking changes
+        _model_name = deployment.litellm_params.model
+        if deployment.litellm_params.custom_llm_provider is not None:
+            _model_name = (
+                deployment.litellm_params.custom_llm_provider + "/" + _model_name
+            )
+
+        # For the shared backend key, strip custom pricing fields so that
+        # one deployment's pricing overrides don't pollute another
+        # deployment sharing the same backend model name.
+        # Each deployment's full pricing is already stored under its
+        # unique model_id above (when present).
+        _custom_pricing_fields = CustomPricingLiteLLMParams.model_fields.keys()
+        _shared_model_info = {
+            k: v for k, v in _model_info_dict.items() if k not in _custom_pricing_fields
+        }
+        _backend_alias_cost = {_model_name: _shared_model_info}
+        if "responses/" in _model_name:
+            _stripped_model_name = _model_name.replace("responses/", "")
+            _backend_alias_cost[_stripped_model_name] = _shared_model_info
+        litellm.register_model(model_cost=_backend_alias_cost)
+
         # add to model names
         self._add_model_to_list_and_index_map(
             model=_deployment, model_id=deployment.model_info.id

tests/test_litellm/test_router_model_cost_isolation.py

@@ -18,6 +18,7 @@
 
 import litellm
 from litellm import Router
+from litellm.types.router import Deployment, LiteLLM_Params, ModelInfo
 
 
 def test_should_not_pollute_shared_key_with_zero_cost_pricing():
@@ -266,3 +267,59 @@ def test_should_preserve_builtin_pricing_regardless_of_deployment_order():
         f"Order should not matter. Expected {builtin_output_cost}, "
         f"got {info_std_2['output_cost_per_token']}"
     )
+
+
+def test_responses_prefix_stripped_alias_registered_for_model_list():
+    """
+    Register ``litellm.model_cost`` under the backend key with ``responses/`` and
+    under the stripped key (``responses_api_bridge_check`` removes that segment).
+    """
+    uid = "responses-strip-alias-test-a1b2c3d4"
+    Router(
+        model_list=[
+            {
+                "model_name": "azure-responses-strip-test",
+                "litellm_params": {
+                    "model": "responses/gpt-strip-test-a1b2c3d4",
+                    "custom_llm_provider": "azure",
+                    "api_key": "fake-key-strip",
+                },
+                "model_info": {
+                    "id": uid,
+                    "supports_native_streaming": True,
+                },
+            }
+        ],
+    )
+    assert "azure/responses/gpt-strip-test-a1b2c3d4" in litellm.model_cost
+    assert "azure/gpt-strip-test-a1b2c3d4" in litellm.model_cost
+    assert (
+        litellm.model_cost["azure/gpt-strip-test-a1b2c3d4"].get(
+            "supports_native_streaming"
+        )
+        is True
+    )
+
+
+def test_responses_prefix_stripped_alias_registered_for_add_deployment():
+    """Dynamic ``add_deployment`` must mirror ``_create_deployment`` registration."""
+    uid = "add-dep-responses-strip-e5f6a7b8"
+    router = Router(model_list=[])
+    deployment = Deployment(
+        model_name="dyn-responses-strip",
+        litellm_params=LiteLLM_Params(
+            model="responses/gpt-add-strip-e5f6a7b8",
+            custom_llm_provider="azure",
+            api_key="fake-key-add",
+        ),
+        model_info=ModelInfo(id=uid, supports_native_streaming=True),
+    )
+    router.add_deployment(deployment=deployment)
+    assert "azure/responses/gpt-add-strip-e5f6a7b8" in litellm.model_cost
+    assert "azure/gpt-add-strip-e5f6a7b8" in litellm.model_cost
+    assert (
+        litellm.model_cost["azure/gpt-add-strip-e5f6a7b8"].get(
+            "supports_native_streaming"
+        )
+        is True
+    )