From 2babac0bed181c28b3b72aed97826a8ae96ae047 Mon Sep 17 00:00:00 2001
From: cjackal <44624812+cjackal@users.noreply.github.com>
Date: Fri, 27 Mar 2026 14:58:20 +0900
Subject: [PATCH] [frontend] dump openai responses type by alias (#38262)

Signed-off-by: cjackal <44624812+cjackal@users.noreply.github.com>
---
 vllm/entrypoints/openai/responses/protocol.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/vllm/entrypoints/openai/responses/protocol.py b/vllm/entrypoints/openai/responses/protocol.py
index 43fbba1dd..609d8e40f 100644
--- a/vllm/entrypoints/openai/responses/protocol.py
+++ b/vllm/entrypoints/openai/responses/protocol.py
@@ -105,8 +105,8 @@ def serialize_message(msg):
     elif hasattr(msg, "to_dict"):
         return msg.to_dict()
     else:
-        # fallback to pyandic dump
-        return msg.model_dump_json()
+        # fallback to pydantic dump
+        return msg.model_dump_json(by_alias=True)
 
 
 def serialize_messages(msgs):