fix(proxy): price a 499 spend row only for the proxy's own disconnect, and never after the call already completed (#47652)

* fix(proxy): price a 499 spend row only for the proxy's own disconnect, and never after the call already completed

* fix(proxy): gate the zero-cost 499 row on the success log being enqueued, not merely claimed

---------

Co-authored-by: devin-ai-integration[bot] <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Backport of #47652 to stable/1.106.x
Cherry-picked from ffb7133d32 (main)

litellm/litellm_core_utils/litellm_logging.py

@@ -760,6 +760,7 @@ class Logging(LiteLLMLoggingBaseClass):
         self.defer_async_logging: bool = False
         self.enqueue_deferred_logging: Callable[[], None] | None = None
         self._async_success_scheduled: bool = False
+        self._async_success_enqueued: bool = False
         self.on_detached_stream_failure: Callable[[Exception], Awaitable[None]] | None = None
         self.shadow_eval_request_snapshot: GuardrailRequestSnapshot | None = None
 
@@ -2296,6 +2297,16 @@ class Logging(LiteLLMLoggingBaseClass):
         except Exception:
             return True
 
+    @property
+    def async_success_log_enqueued(self) -> bool:
+        """True once the success log task was actually created, not merely claimed, so a later failure raised
+        around it (a disconnect cancelling a still-pending guardrail task) must not bill the prompt a second
+        time. A claimed log parked in the deferred slot never runs once a 499 interrupts, so it stays False."""
+        return self._async_success_enqueued
+
+    def mark_async_success_log_enqueued(self) -> None:
+        self._async_success_enqueued = True
+
     def claim_async_success_log(self) -> bool:
         """One async success log per request. The innermost @client wrapper always exits first,
         since the outer one is awaiting it, so it claims the log here and the outer wrapper gets

litellm/proxy/utils.py

@@ -1323,8 +1323,9 @@ def _timed_out_reading_from_provider(exception: Exception) -> bool:
 
 
 def _client_disconnected(exception: Exception) -> bool:
-    """The 499 the proxy raises when the caller hung up while the provider was still working on the request."""
-    return getattr(exception, "status_code", None) == LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED
+    """The 499 the proxy itself raises when the caller hung up while the provider was still working on the
+    request. A provider's own 499 arrives as a litellm exception and is a plain upstream failure."""
+    return isinstance(exception, HTTPException) and exception.status_code == LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED
 
 
 def _provider_billed_the_failure(exception: Exception) -> bool:
@@ -1346,17 +1347,19 @@ def _failure_fields_to_lift(request_data: Mapping[str, object], provider_billed:
     _litellm_params: Final = getattr(_logging_obj, "litellm_params", None)
     _base_model: Final = get_base_model_from_metadata(model_call_details=_model_call_details)
     _deployment_id: Final = _logging_obj.get_router_model_id() if isinstance(_logging_obj, Logging) else None
+    _success_already_logged: Final = isinstance(_logging_obj, Logging) and _logging_obj.async_success_log_enqueued
+    _billed: Final = provider_billed and not _success_already_logged
     _usage_to_lift: Final = _failure_usage_to_lift(
         model_call_details=_model_call_details,
         request_body=request_data,
         dispatched=_first_handoff is not None,
-        provider_billed=provider_billed,
+        provider_billed=_billed,
         deployment_id=_deployment_id,
         base_model=_base_model,
     )
     _prompt_estimate: Final = (
         _estimated_prompt_usage(_model_call_details, request_data)
-        if provider_billed and _first_handoff is not None and not _model_call_details.get("failed_attempts_usage")
+        if _billed and _first_handoff is not None and not _model_call_details.get("failed_attempts_usage")
         else None
     )
     _earlier_attempts: Final = (

litellm/utils.py

@@ -1385,6 +1385,7 @@ def _schedule_async_success_logging(
         return
 
     def _enqueue_async_logging() -> None:
+        logging_obj.mark_async_success_log_enqueued()
         asyncio.create_task(
             _client_async_logging_helper(
                 logging_obj=logging_obj,

tests/unit/proxy/test_proxy_utils_model_creation_and_error_logging.py

@@ -828,6 +828,125 @@ class TestPostCallFailureHookEstimatesDispatchedInputTokens:
         assert expected_input_cost > 0
         assert request_data["response_cost"] == pytest.approx(expected_input_cost)
 
+    @pytest.mark.asyncio
+    async def test_upstream_499_error_is_a_plain_failure_not_a_priced_disconnect(self):
+        """A provider answering HTTP 499 surfaces as litellm.APIError with status_code 499. Only the
+        proxy's own disconnect HTTPException means the caller hung up mid-generation, so the upstream
+        error keeps the estimated usage at zero cost like any other post-dispatch provider error."""
+        from datetime import datetime
+
+        from litellm.constants import LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED
+        from litellm.types.utils import Usage
+
+        request_data = {
+            "litellm_logging_obj": self._logging_obj(
+                {
+                    "first_api_call_start_time": datetime(2026, 1, 1, 12, 0, 0),
+                    "model": "gpt-3.5-turbo",
+                    "messages": [{"role": "user", "content": "count these input tokens please"}],
+                    "call_type": "acompletion",
+                }
+            ),
+            "metadata": {},
+        }
+        await self._run(
+            request_data,
+            original_exception=litellm.APIError(
+                status_code=LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED,
+                message="client closed request",
+                llm_provider="openai",
+                model="gpt-3.5-turbo",
+            ),
+        )
+
+        estimated = request_data["combined_usage_object"]
+        assert isinstance(estimated, Usage)
+        assert estimated.prompt_tokens > 0
+        assert request_data["response_cost"] == 0.0
+
+    @pytest.mark.asyncio
+    async def test_client_disconnect_after_the_call_already_completed_is_not_priced_again(self):
+        """The LLM task finished and claimed its success log (which carries the real usage and cost)
+        while a during_call guardrail task was still pending, then the caller hung up. The 499 raised
+        for that disconnect must not price the prompt a second time."""
+        from datetime import datetime
+
+        from fastapi import HTTPException
+
+        from litellm.constants import LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED
+        from litellm.litellm_core_utils.litellm_logging import Logging
+
+        logging_obj = Logging(
+            model="gpt-3.5-turbo",
+            messages=[{"role": "user", "content": "count these input tokens please"}],
+            stream=False,
+            call_type="acompletion",
+            start_time=datetime(2026, 1, 1, 12, 0, 0),
+            litellm_call_id="completed-before-disconnect",
+            function_id="fn",
+        )
+        logging_obj.model_call_details.update(
+            {
+                "first_api_call_start_time": datetime(2026, 1, 1, 12, 0, 1),
+                "model": "gpt-3.5-turbo",
+                "messages": [{"role": "user", "content": "count these input tokens please"}],
+                "call_type": "acompletion",
+            }
+        )
+        assert logging_obj.claim_async_success_log()
+        logging_obj.mark_async_success_log_enqueued()
+        request_data = {"litellm_logging_obj": logging_obj, "metadata": {}}
+        await self._run(
+            request_data,
+            original_exception=HTTPException(
+                status_code=LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED, detail="Client disconnected the request"
+            ),
+        )
+
+        assert request_data.get("response_cost", 0.0) == 0.0
+
+    @pytest.mark.asyncio
+    async def test_client_disconnect_with_a_claimed_but_deferred_success_log_is_still_priced(self):
+        """With a post_call guardrail registered the success log is claimed but parked in the deferred slot,
+        and a 499 raised before the flush means it never runs. Nothing else bills that request, so the
+        failure row keeps the estimated input cost."""
+        from datetime import datetime
+
+        from fastapi import HTTPException
+
+        from litellm.constants import LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED
+        from litellm.litellm_core_utils.litellm_logging import Logging
+
+        logging_obj = Logging(
+            model="gpt-3.5-turbo",
+            messages=[{"role": "user", "content": "count these input tokens please"}],
+            stream=False,
+            call_type="acompletion",
+            start_time=datetime(2026, 1, 1, 12, 0, 0),
+            litellm_call_id="deferred-success-never-flushed",
+            function_id="fn",
+        )
+        logging_obj.model_call_details.update(
+            {
+                "first_api_call_start_time": datetime(2026, 1, 1, 12, 0, 1),
+                "model": "gpt-3.5-turbo",
+                "messages": [{"role": "user", "content": "count these input tokens please"}],
+                "call_type": "acompletion",
+            }
+        )
+        logging_obj.defer_async_logging = True
+        assert logging_obj.claim_async_success_log()
+        logging_obj.enqueue_deferred_logging = lambda: None
+        request_data = {"litellm_logging_obj": logging_obj, "metadata": {}}
+        await self._run(
+            request_data,
+            original_exception=HTTPException(
+                status_code=LITELLM_HTTP_STATUS_CLIENT_DISCONNECTED, detail="Client disconnected the request"
+            ),
+        )
+
+        assert request_data["response_cost"] > 0.0
+
     @pytest.mark.asyncio
     async def test_client_disconnect_before_provider_handoff_is_not_priced(self):
         """A caller that hung up while the request was still in pre-call hooks never reached the