Fix Vertex metadata redaction bypass in logging callbacks.

Scrub Vertex provider fields from litellm_params.metadata.hidden_params during perform_redaction so streaming success_handler merges do not leak prompt-derived metadata when message logging is disabled.

Co-authored-by: Cursor <cursoragent@cursor.com>

litellm/litellm_core_utils/redact_messages.py

@@ -128,6 +128,30 @@ def _redact_vertex_provider_metadata(obj: Any) -> None:
             hidden_params.pop(field, None)
 
 
+def _redact_vertex_provider_metadata_from_litellm_params(
+    model_call_details: dict,
+) -> None:
+    """
+    Scrub Vertex provider metadata copied into litellm_params metadata.
+
+    success_handler() merges response._hidden_params into
+    litellm_params.metadata['hidden_params'] before perform_redaction() runs.
+    """
+    litellm_params = model_call_details.get("litellm_params")
+    if not isinstance(litellm_params, dict):
+        return
+
+    for metadata_key in ("metadata", "litellm_metadata"):
+        metadata = litellm_params.get(metadata_key)
+        if not isinstance(metadata, dict):
+            continue
+        hidden_params = metadata.get("hidden_params")
+        if not isinstance(hidden_params, dict):
+            continue
+        for field in VERTEX_PROVIDER_METADATA_FIELDS:
+            hidden_params.pop(field, None)
+
+
 def _redact_standard_logging_object(model_call_details: dict):
     """Redact messages and response inside standard_logging_object if present."""
     standard_logging_object = model_call_details.get("standard_logging_object")
@@ -194,6 +218,7 @@ def perform_redaction(model_call_details: dict, result):
     model_call_details["prompt"] = ""
     model_call_details["input"] = ""
     _redact_standard_logging_object(model_call_details)
+    _redact_vertex_provider_metadata_from_litellm_params(model_call_details)
 
     # Redact streaming response
     if (

tests/test_litellm/litellm_core_utils/test_redact_messages.py

@@ -412,3 +412,33 @@ class TestPerformRedaction:
         assert response.choices[0].message.content == "redacted-by-litellm"
         assert getattr(response, "vertex_ai_grounding_metadata") == []
         assert "vertex_ai_grounding_metadata" not in response._hidden_params
+
+    def test_redacts_vertex_provider_metadata_from_metadata_hidden_params(self):
+        """Streaming success_handler copies _hidden_params into metadata before redaction."""
+        details = {
+            "stream": True,
+            "litellm_params": {
+                "metadata": {
+                    "hidden_params": {
+                        "response_cost": 0.01,
+                        "vertex_ai_grounding_metadata": [
+                            {"webSearchQueries": ["sensitive search term"]}
+                        ],
+                        "vertex_ai_url_context_metadata": [
+                            {"urlMetadata": [{"retrievedUrl": "https://example.com"}]}
+                        ],
+                        "vertex_ai_safety_ratings": [{"category": "HARM"}],
+                        "vertex_ai_citation_metadata": [{"citations": ["source"]}],
+                    }
+                }
+            },
+        }
+
+        perform_redaction(details, None)
+
+        hidden_params = details["litellm_params"]["metadata"]["hidden_params"]
+        assert hidden_params["response_cost"] == 0.01
+        assert "vertex_ai_grounding_metadata" not in hidden_params
+        assert "vertex_ai_url_context_metadata" not in hidden_params
+        assert "vertex_ai_safety_ratings" not in hidden_params
+        assert "vertex_ai_citation_metadata" not in hidden_params