diff --git a/litellm/litellm_core_utils/llm_response_utils/convert_dict_to_response.py b/litellm/litellm_core_utils/llm_response_utils/convert_dict_to_response.py
index 8b94c34942c..66ec5eed4c7 100644
--- a/litellm/litellm_core_utils/llm_response_utils/convert_dict_to_response.py
+++ b/litellm/litellm_core_utils/llm_response_utils/convert_dict_to_response.py
@@ -785,7 +785,7 @@ def convert_to_model_response_object(
                     # Preserve provider_specific_fields if already present
                     # in the response (e.g. from proxy passthrough)
                     provider_specific_fields = dict(choice["message"].get("provider_specific_fields", None) or {})
-                    for f in choice["message"].keys() - _MESSAGE_FIELDS:
+                    for f in choice["message"].keys() - _MESSAGE_FIELDS - {"reasoning"}:
                         provider_specific_fields[f] = choice["message"][f]
 
                     # Handle reasoning models that display `reasoning_content` within `content`
diff --git a/litellm/litellm_core_utils/redact_messages.py b/litellm/litellm_core_utils/redact_messages.py
index 7f8a38cc8ec..925c5cb80d3 100644
--- a/litellm/litellm_core_utils/redact_messages.py
+++ b/litellm/litellm_core_utils/redact_messages.py
@@ -198,6 +198,7 @@ def _redacted_provider_specific_fields(fields: Mapping[str, object]) -> Mapping[
     return {
         **fields,
         **({"reasoning_content": REDACTED_BY_LITELLM} if fields.get("reasoning_content") is not None else {}),
+        **({"reasoning": REDACTED_BY_LITELLM} if fields.get("reasoning") is not None else {}),
         **{
             key: None
             for key in (
@@ -206,6 +207,7 @@ def _redacted_provider_specific_fields(fields: Mapping[str, object]) -> Mapping[
                 "citations",
                 "compaction_blocks",
                 "compaction_delta",
+                "reasoning_details",
             )
             if key in fields
         },
diff --git a/tests/unit/litellm_core_utils/llm_response_utils/test_convert_dict_to_response.py b/tests/unit/litellm_core_utils/llm_response_utils/test_convert_dict_to_response.py
index 0c601a6b2c8..51b47d8c014 100644
--- a/tests/unit/litellm_core_utils/llm_response_utils/test_convert_dict_to_response.py
+++ b/tests/unit/litellm_core_utils/llm_response_utils/test_convert_dict_to_response.py
@@ -2873,6 +2873,28 @@ class TestConvertToModelResponseObjectCompletion:
         assert message.reasoning_content == "2+2=4"
         assert "reasoning_content" not in (message.provider_specific_fields or {})
 
+    def test_reasoning_not_mirrored_into_provider_specific_fields(self):
+        response_object = {
+            "id": "chatcmpl-6",
+            "model": "openrouter/deepseek/deepseek-r1",
+            "choices": [
+                {
+                    "finish_reason": "stop",
+                    "index": 0,
+                    "message": {"content": "The answer is 4.", "role": "assistant", "reasoning": "2+2=4"},
+                }
+            ],
+            "usage": {"prompt_tokens": 5, "completion_tokens": 10, "total_tokens": 15},
+        }
+
+        result = convert_to_model_response_object(
+            response_object=response_object,
+            model_response_object=ModelResponse(),
+        )
+        message = result.choices[0].message
+        assert message.reasoning_content == "2+2=4"
+        assert "reasoning" not in (message.provider_specific_fields or {})
+
     def test_response_none_raises(self):
         with pytest.raises(Exception, match="Invalid response object"):
             convert_to_model_response_object(
diff --git a/tests/unit/litellm_core_utils/test_redact_messages.py b/tests/unit/litellm_core_utils/test_redact_messages.py
index 6a734ca3b70..0262f30c258 100644
--- a/tests/unit/litellm_core_utils/test_redact_messages.py
+++ b/tests/unit/litellm_core_utils/test_redact_messages.py
@@ -53,6 +53,8 @@ SIGNATURE: Final = "opaque-thought-signature"
 def _provider_fields() -> dict[str, object]:
     return {
         "reasoning_content": SECRET,
+        "reasoning": SECRET,
+        "reasoning_details": [{"type": "reasoning.text", "text": SECRET, "index": 0, "format": "unknown"}],
         "thinking_blocks": [{"type": "thinking", "thinking": SECRET}],
         "reasoningContentBlocks": [{"reasoningText": {"text": SECRET}}],
         "citations": [{"cited_text": SECRET}],