fix(proxy): strip client standard_logging_object and zero-fill unknown recovered cost on the failure path

Auth and pass-through failures reach post_call_failure_hook with the raw request body unstripped, so a client-supplied standard_logging_object could feed the new attribution fallback when the logging object carries none. Pop the key before the lift so only the logging object may supply it. Also coalesce a None recovered cost to 0.0 so the lift always overwrites any client-supplied response_cost, matching the merge base's clobber semantics.

litellm/proxy/utils.py

@@ -539,7 +539,7 @@ def _failure_fields_to_lift(request_data: Mapping[str, object]) -> Mapping[str,
     _entries: Final = (
         ("first_api_call_start_time", _first_handoff),
         ("combined_usage_object", None if _usage_to_lift is None else _usage_to_lift[0]),
-        ("response_cost", None if _usage_to_lift is None else _usage_to_lift[1]),
+        ("response_cost", None if _usage_to_lift is None else (_usage_to_lift[1] or 0.0)),
         ("standard_logging_object", _model_call_details.get("standard_logging_object")),
     )
     return MappingProxyType({key: value for key, value in _entries if value is not None})
@@ -2322,6 +2322,9 @@ class ProxyLogging:
                 original_exception=original_exception,
             )
 
+        # Auth and pass-through failures reach this hook with the raw request
+        # body unstripped, so only the logging object may supply this key.
+        request_data.pop("standard_logging_object", None)
         request_data.update(_failure_fields_to_lift(request_data))
 
         # Remove before callbacks iterate — not serialisable

tests/test_litellm/proxy/test_proxy_utils.py

@@ -468,6 +468,23 @@ class TestPostCallFailureHookLiftsRecoveredPartialSpend:
         assert request_data["response_cost"] == 3.5e-05
         assert "litellm_logging_obj" not in request_data
 
+    @pytest.mark.asyncio
+    async def test_recovered_usage_without_cost_clobbers_client_cost_with_zero(self):
+        from litellm.types.utils import Usage
+
+        recovered_usage = Usage(prompt_tokens=30, completion_tokens=1, total_tokens=31)
+        logging_obj = MagicMock()
+        logging_obj.model_call_details = {"combined_usage_object": recovered_usage}
+        request_data = {
+            "litellm_logging_obj": logging_obj,
+            "response_cost": 999.0,
+            "metadata": {},
+        }
+        await self._run(request_data)
+
+        assert request_data["combined_usage_object"] is recovered_usage
+        assert request_data["response_cost"] == 0.0
+
     @pytest.mark.asyncio
     async def test_no_recovered_usage_is_noop(self):
         logging_obj = MagicMock()
@@ -522,6 +539,23 @@ class TestPostCallFailureHookLiftsStandardLoggingObject:
         await self._run(request_data)
         assert request_data["standard_logging_object"] is authoritative
 
+    @pytest.mark.asyncio
+    async def test_client_supplied_key_is_stripped_when_logging_obj_supplies_none(self):
+        spoofed = {"model_id": "client-injected"}
+        request_data = {"standard_logging_object": spoofed, "metadata": {}}
+        await self._run(request_data)
+        assert "standard_logging_object" not in request_data
+
+        logging_obj = MagicMock()
+        logging_obj.model_call_details = {}
+        request_data_with_obj = {
+            "litellm_logging_obj": logging_obj,
+            "standard_logging_object": spoofed,
+            "metadata": {},
+        }
+        await self._run(request_data_with_obj)
+        assert "standard_logging_object" not in request_data_with_obj
+
     @pytest.mark.asyncio
     async def test_no_standard_logging_object_is_noop(self):
         logging_obj = MagicMock()