diff --git a/eval_protocol/pytest/tracing_utils.py b/eval_protocol/pytest/tracing_utils.py
index f2a727db..279d1055 100644
--- a/eval_protocol/pytest/tracing_utils.py
+++ b/eval_protocol/pytest/tracing_utils.py
@@ -28,7 +28,55 @@ def fetch_traces() -> List[EvaluationRow]:
             include_payloads=config.include_payloads,
         )
 
-    return DynamicDataLoader(generators=[fetch_traces], preprocess_fn=filter_longest_conversation)
+    def preprocess_traces(rows: List[EvaluationRow]) -> List[EvaluationRow]:
+        filtered_rows = filter_longest_conversation(rows)
+        if config.include_payloads and filtered_rows:
+            _merge_payloads_into_longest_row(filtered_rows[0], rows)
+        return filtered_rows
+
+    return DynamicDataLoader(generators=[fetch_traces], preprocess_fn=preprocess_traces)
+
+
+def _merge_payloads_into_longest_row(longest_row: EvaluationRow, rows: List[EvaluationRow]) -> None:
+    """
+    Preserve per-turn payload-derived metadata after selecting the longest trace row.
+
+    Each trace row carries payloads for its final assistant turn. The longest row
+    keeps the full conversation, while its top-level execution metadata remains
+    the payload metadata for the final completion for backward compatibility.
+    """
+    target_assistants = longest_row.get_assistant_messages()
+    assistant_turn_payloads = []
+
+    for row in sorted(rows, key=lambda item: len(item.messages)):
+        source = row.last_assistant_message()
+        source_turn_index = len(row.get_assistant_messages()) - 1
+        if source_turn_index < 0 or source_turn_index >= len(target_assistants):
+            continue
+
+        if source and source.logprobs and not target_assistants[source_turn_index].logprobs:
+            target_assistants[source_turn_index].logprobs = source.logprobs
+
+        extra = row.execution_metadata.extra or {}
+        turn_payload = {
+            key: extra[key]
+            for key in (
+                "completion_logprobs",
+                "completion_token_ids",
+                "logprobs_metadata",
+                "routing_matrices",
+                "routing_metadata",
+            )
+            if key in extra
+        }
+        if turn_payload:
+            turn_payload["assistant_turn_index"] = source_turn_index
+            assistant_turn_payloads.append(turn_payload)
+
+    if assistant_turn_payloads:
+        if longest_row.execution_metadata.extra is None:
+            longest_row.execution_metadata.extra = {}
+        longest_row.execution_metadata.extra["assistant_turn_payloads"] = assistant_turn_payloads
 
 
 def build_fireworks_tracing_url(
diff --git a/tests/pytest/test_tracing_utils.py b/tests/pytest/test_tracing_utils.py
new file mode 100644
index 00000000..58ec55c1
--- /dev/null
+++ b/tests/pytest/test_tracing_utils.py
@@ -0,0 +1,57 @@
+from eval_protocol.models import EvaluationRow, ExecutionMetadata, Message
+from eval_protocol.pytest.tracing_utils import _merge_payloads_into_longest_row
+
+
+def test_merge_payloads_into_longest_row_preserves_each_assistant_turn():
+    first_turn_logprobs = {"content": [{"logprob": -0.1}, {"logprob": -0.2}]}
+    second_turn_logprobs = {"content": [{"logprob": -0.3}]}
+    first_turn = EvaluationRow(
+        messages=[
+            Message(role="user", content="What is 2+2?"),
+            Message(role="assistant", content="4", logprobs=first_turn_logprobs),
+        ],
+        execution_metadata=ExecutionMetadata(
+            extra={
+                "completion_logprobs": [-0.1, -0.2],
+                "routing_matrices": ["first-matrix"],
+                "routing_metadata": {"total_token_count": 1},
+            },
+        ),
+    )
+    second_turn = EvaluationRow(
+        messages=[
+            Message(role="user", content="What is 2+2?"),
+            Message(role="assistant", content="4"),
+            Message(role="user", content="Use that in a sentence."),
+            Message(role="assistant", content="4", logprobs=second_turn_logprobs),
+        ],
+        execution_metadata=ExecutionMetadata(
+            extra={
+                "completion_logprobs": [-0.3],
+                "routing_matrices": ["second-matrix"],
+                "routing_metadata": {"total_token_count": 1},
+            },
+        ),
+    )
+
+    _merge_payloads_into_longest_row(second_turn, [first_turn, second_turn])
+
+    assistant_messages = second_turn.get_assistant_messages()
+    assert assistant_messages[0].logprobs == first_turn_logprobs
+    assert assistant_messages[1].logprobs == second_turn_logprobs
+    assert second_turn.execution_metadata.extra is not None
+    assert second_turn.execution_metadata.extra["routing_matrices"] == ["second-matrix"]
+    assert second_turn.execution_metadata.extra["assistant_turn_payloads"] == [
+        {
+            "assistant_turn_index": 0,
+            "completion_logprobs": [-0.1, -0.2],
+            "routing_matrices": ["first-matrix"],
+            "routing_metadata": {"total_token_count": 1},
+        },
+        {
+            "assistant_turn_index": 1,
+            "completion_logprobs": [-0.3],
+            "routing_matrices": ["second-matrix"],
+            "routing_metadata": {"total_token_count": 1},
+        },
+    ]