diff --git a/eval_protocol/models.py b/eval_protocol/models.py
index 2804db59..e2bf355f 100644
--- a/eval_protocol/models.py
+++ b/eval_protocol/models.py
@@ -269,6 +269,11 @@ class Message(BaseModel):
     tool_calls: Optional[List[ChatCompletionMessageToolCall]] = None
     function_call: Optional[FunctionCall] = None
     control_plane_step: Optional[Dict[str, Any]] = None
+    weight: Optional[int] = None
+
+    def dump_mdoel_for_chat_completion_request(self):
+        """Only keep chat completion accepted fields"""
+        return self.model_dump(exclude_none=True, exclude={"control_plane_step", "reasoning_content", "weight"})
 
     @classmethod
     def model_validate(cls, obj, *args, **kwargs):
diff --git a/tests/adapters/test_openai_responses_adapter.py b/tests/adapters/test_openai_responses_adapter.py
index bf9edd98..6091e52f 100644
--- a/tests/adapters/test_openai_responses_adapter.py
+++ b/tests/adapters/test_openai_responses_adapter.py
@@ -22,7 +22,10 @@ def test_openai_responses_adapter_with_real_response_simple(snapshot: SnapshotAs
     assert len(eval_rows) == 1
 
     # Convert to dict for snapshot testing
-    eval_rows_dict = [row.model_dump(exclude={"created_at", "execution_metadata"}) for row in eval_rows]
+    eval_rows_dict = [
+        row.model_dump(exclude={"created_at": True, "execution_metadata": True, "messages": {"__all__": {"weight"}}})
+        for row in eval_rows
+    ]
 
     # Assert against snapshot
     assert eval_rows_dict == snapshot
@@ -42,7 +45,10 @@ def test_openai_responses_adapter_with_real_response_parallel_tool_calls(snapsho
     assert len(eval_rows) == 1
 
     # Convert to dict for snapshot testing
-    eval_rows_dict = [row.model_dump(exclude={"created_at", "execution_metadata"}) for row in eval_rows]
+    eval_rows_dict = [
+        row.model_dump(exclude={"created_at": True, "execution_metadata": True, "messages": {"__all__": {"weight"}}})
+        for row in eval_rows
+    ]
 
     # Assert against snapshot
     assert eval_rows_dict == snapshot
diff --git a/tests/test_models.py b/tests/test_models.py
index 9e0f09f9..723685b8 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -694,3 +694,30 @@ def test_evaluation_row_extra_fields():
     assert "eval" in dictionary
     assert "accuracy" in dictionary["eval_details"]["metrics"]
     assert "test" in dictionary["extra_fields"]
+
+
+def test_message_with_weight_dump():
+    example = {
+        "role": "user",
+        "content": "Hello, how are you?",
+        "weight": 0,
+    }
+
+    message = Message(**example)
+    dictionary = message.model_dump()
+    assert "weight" in dictionary
+    assert dictionary["weight"] == 0
+
+
+def test_message_dump_for_chat_completion_request():
+    example = {
+        "role": "user",
+        "content": "Hello, how are you?",
+        "weight": 0,
+        "reasoning_content": "I am thinking about the user's question",
+    }
+    message = Message(**example)
+    dictionary = message.dump_mdoel_for_chat_completion_request()
+    assert "weight" not in dictionary
+    assert "reasoning_content" not in dictionary
+    assert dictionary["content"] == "Hello, how are you?"