From cafe24f0c8a88b4ceb61af0025f6f7bd36b6245a Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Wed, 14 Oct 2026 04:41:32 -0700
Subject: [PATCH] fix(proxy): keep a non-string client model_group out of spend
 rows

---
 .../spend_tracking/spend_tracking_utils.py    |  8 +++++--
 .../test_spend_tracking_utils.py              | 22 +++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/litellm/proxy/spend_tracking/spend_tracking_utils.py b/litellm/proxy/spend_tracking/spend_tracking_utils.py
index 99bd2fbc480..4446dcff066 100644
--- a/litellm/proxy/spend_tracking/spend_tracking_utils.py
+++ b/litellm/proxy/spend_tracking/spend_tracking_utils.py
@@ -401,7 +401,11 @@ def _sl_attribution_fallback(
 ) -> str:
     if standard_logging_payload is None:
         return ""
-    return standard_logging_payload.get(field) or ""
+    return _string_or_empty(standard_logging_payload.get(field))
+
+
+def _string_or_empty(value: object) -> str:
+    return value if isinstance(value, str) else ""
 
 
 def _deployment_provider(deployment: DeploymentTypedDict) -> str | None:
@@ -600,7 +604,7 @@ def get_logging_payload(
     _model_id: Final = metadata.get("model_info", {}).get("id", "") or _sl_attribution_fallback(
         standard_logging_payload, "model_id"
     )
-    _model_group: Final = metadata.get("model_group", "") or _sl_attribution_fallback(
+    _model_group: Final = _string_or_empty(metadata.get("model_group")) or _sl_attribution_fallback(
         standard_logging_payload, "model_group"
     )
     _api_base: Final = litellm_params.get("api_base", "") or _sl_attribution_fallback(
diff --git a/tests/unit/proxy/spend_tracking/test_spend_tracking_utils.py b/tests/unit/proxy/spend_tracking/test_spend_tracking_utils.py
index 4d299f05fbe..94fa6c3767e 100644
--- a/tests/unit/proxy/spend_tracking/test_spend_tracking_utils.py
+++ b/tests/unit/proxy/spend_tracking/test_spend_tracking_utils.py
@@ -4900,6 +4900,28 @@ def test_get_logging_payload_router_rejected_request_takes_provider_from_model_g
     assert payload["custom_llm_provider"] == expected_provider
 
 
+@pytest.mark.parametrize("client_model_group", [7, ["embed-only"], {"name": "embed-only"}])
+def test_get_logging_payload_drops_a_client_model_group_that_is_not_a_string(client_model_group: object):
+    payload: Final = get_logging_payload(
+        kwargs={
+            "model": "embed-only",
+            "litellm_params": {
+                "metadata": {"user_api_key": "test-key", "model_group": client_model_group, "status": "failure"}
+            },
+            "standard_logging_object": {
+                **_make_failed_request_standard_logging_payload(),
+                "model_group": client_model_group,
+            },
+        },
+        response_obj={},
+        start_time=datetime.datetime.now(timezone.utc),
+        end_time=datetime.datetime.now(timezone.utc),
+        llm_router=None,
+    )
+
+    assert payload["model_group"] == ""
+
+
 def test_get_logging_payload_router_rejected_request_without_router_leaves_provider_empty():
     assert _router_rejected_failure_payload("openai-group", None)["custom_llm_provider"] == ""