From f6db62e07bce492f977194788af035852506dcf3 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 20 May 2026 22:05:40 +0000
Subject: [PATCH] Reuse observability span message serialization

---
 python/packages/core/agent_framework/observability.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/python/packages/core/agent_framework/observability.py b/python/packages/core/agent_framework/observability.py
index 8a5ff14bbf..7c63581c19 100644
--- a/python/packages/core/agent_framework/observability.py
+++ b/python/packages/core/agent_framework/observability.py
@@ -2158,8 +2158,10 @@ def _capture_messages(
     normalized_messages = normalize_messages(messages)
     logging_messages = prepend_instructions_to_messages(normalized_messages, system_instructions)
     span_messages = [_to_otel_message(message) for message in normalized_messages]
+    span_message_iter = iter(span_messages)
+    prepended_count = len(logging_messages) - len(normalized_messages)
     for index, message in enumerate(logging_messages):
-        otel_message = _to_otel_message(message)
+        otel_message = _to_otel_message(message) if index < prepended_count else next(span_message_iter)
         # Reuse the otel message representation for logging instead of calling to_dict()
         # to avoid expensive Pydantic serialization overhead
         logger.info(