fix(logging): read used_client_oauth_token from the proxy-stamped metadata slot

On routes that carry proxy metadata in litellm_metadata, metadata is the
caller's own body field, and merge_litellm_metadata lets it win. Resolve the
flag from litellm_metadata when the proxy stamped it there so a caller cannot
set it in the standard logging payload

litellm/litellm_core_utils/litellm_logging.py

@@ -288,6 +288,13 @@ _STANDARD_LOGGING_METADATA_KEYS: Final[frozenset[str]] = (
 )
 
 
+def _proxy_stamped_used_client_oauth_token(metadata: object, litellm_params: Mapping[str, object] | None) -> object:
+    litellm_metadata: Final = litellm_params.get("litellm_metadata") if litellm_params is not None else None
+    if isinstance(litellm_metadata, Mapping) and "used_client_oauth_token" in litellm_metadata:
+        return litellm_metadata["used_client_oauth_token"]
+    return metadata.get("used_client_oauth_token") if isinstance(metadata, Mapping) else None
+
+
 def _get_provider_request_id(original_exception: Exception) -> str | None:
     try:
         error_response: Final = getattr(original_exception, "response", None)
@@ -5786,7 +5793,7 @@ class StandardLoggingPayloadSetup:
             team_alias=None,
             team_id=None,
             used_client_oauth_token=resolve_used_client_oauth_token(
-                metadata.get("used_client_oauth_token") if isinstance(metadata, dict) else None,
+                _proxy_stamped_used_client_oauth_token(metadata, litellm_params),
                 custom_llm_provider,
             ),
         )

tests/unit/litellm_core_utils/test_litellm_logging.py

@@ -4891,6 +4891,42 @@ def test_get_standard_logging_object_payload_resolves_used_client_oauth_token_ag
     assert payload["metadata"]["used_client_oauth_token"] is expected
 
 
+@pytest.mark.parametrize(
+    "metadata, litellm_metadata, expected",
+    [
+        ({"used_client_oauth_token": True}, {"used_client_oauth_token": False}, False),
+        ({"used_client_oauth_token": False}, {"used_client_oauth_token": True}, True),
+        ({"used_client_oauth_token": True}, {"compression_savings": 1}, True),
+    ],
+)
+def test_get_standard_logging_object_payload_takes_used_client_oauth_token_from_the_proxy_stamped_slot(
+    logging_obj, metadata: dict, litellm_metadata: dict, expected: bool
+):
+    """On routes that carry proxy metadata in `litellm_metadata`, `metadata` is the caller's own body field,
+    so a caller writing the flag there must not override what the proxy stamped."""
+    from datetime import datetime
+
+    from litellm.litellm_core_utils.litellm_logging import get_standard_logging_object_payload
+
+    now = datetime.now()
+    payload = get_standard_logging_object_payload(
+        kwargs={
+            "model": "claude-sonnet-5",
+            "messages": [],
+            "custom_llm_provider": "anthropic",
+            "litellm_params": {"metadata": metadata, "litellm_metadata": litellm_metadata},
+        },
+        init_response_obj={},
+        start_time=now,
+        end_time=now,
+        logging_obj=logging_obj,
+        status="success",
+    )
+
+    assert payload is not None
+    assert payload["metadata"]["used_client_oauth_token"] is expected
+
+
 def test_get_standard_logging_object_payload_carries_matched_access_groups(logging_obj):
     """Access groups stamped at auth time reach the logging payload, so integrations see what a request billed."""
     from datetime import datetime