fix(guardrails): send Lakera Gemini function results without the logging sanitizer

The logging sanitizer rewrites keys and truncates deep values, so a result could reach the
provider with text Lakera never saw. Results are now encoded as plain JSON.

litellm/proxy/guardrails/guardrail_hooks/lakera_ai_v2.py

@@ -1,4 +1,5 @@
 import copy
+import json
 import os
 from collections.abc import Mapping, Sequence
 from datetime import datetime
@@ -17,7 +18,6 @@ from litellm.integrations.custom_guardrail import (
     CustomGuardrail,
 )
 from litellm.litellm_core_utils.core_helpers import as_str_mapping
-from litellm.litellm_core_utils.safe_json_dumps import safe_dumps
 from litellm.llms.base_llm.guardrail_translation.utils import (
     effective_skip_system_message_for_guardrail,
     effective_skip_tool_message_for_guardrail,
@@ -253,7 +253,7 @@ def _gemini_tool_results(content: object) -> str:
     part_fields: Final = (as_str_mapping(part) or {} for part in parts)
     responses: Final = (fields.get("functionResponse") or fields.get("function_response") for fields in part_fields)
     results: Final = ((as_str_mapping(response) or {}).get("response") for response in responses)
-    return "\n".join(safe_dumps(result) for result in results if result)
+    return "\n".join(json.dumps(result, default=str, ensure_ascii=False) for result in results if result)
 
 
 def _has_gemini_contents(data: object, call_type: str | None) -> bool:

tests/unit/proxy/guardrails/guardrail_hooks/test_lakera_ai_v2.py

@@ -1782,6 +1782,15 @@ class TestGeminiContents:
             == GEMINI_INSPECTION_MESSAGES
         )
 
+    def test_gemini_function_response_reaches_inspection_exactly_as_the_provider_gets_it(self):
+        result: Final = {"output": "4111 1111 1111 1111", "\x00output": "clean", "name": "José"}
+        data: Final = {"contents": [{"parts": [{"functionResponse": {"name": "lookup", "response": result}}]}]}
+
+        messages: Final = _build_lakera_inspection_messages(data, call_type="pass_through_endpoint")
+
+        assert json.loads(messages[0]["content"]) == result
+        assert "José" in messages[0]["content"]
+
     @pytest.mark.parametrize("field", ["functionResponse", "function_response"])
     def test_gemini_function_response_is_read_as_a_tool_turn(self, field: str):
         data: Final = {