From 631bd20c3537ce85bbaec02f9e0049c88fa8fdd4 Mon Sep 17 00:00:00 2001
From: Timothy Jaeryang Baek <tim@openwebui.com>
Date: Tue, 24 Mar 2026 17:46:33 -0500
Subject: [PATCH] refac

---
 backend/open_webui/utils/middleware.py |  5 +++++
 backend/open_webui/utils/misc.py       | 27 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index 62c62833e..8379233c5 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -92,6 +92,7 @@ from open_webui.utils.misc import (
     get_last_user_message_item,
     get_last_assistant_message,
     get_system_message,
+    merge_system_messages,
     replace_system_message_content,
     prepend_to_first_user_message_content,
     convert_logit_bias_input_to_json,
@@ -2696,6 +2697,10 @@ async def process_chat_payload(request, form_data, user, metadata, model):
     # to prevent errors from providers like Gemini and Claude
     form_data['messages'] = strip_empty_content_blocks(form_data.get('messages', []))
 
+    # Merge any duplicate system messages into a single message at position 0
+    # to prevent template parsing errors with strict chat templates (e.g. Qwen)
+    form_data['messages'] = merge_system_messages(form_data.get('messages', []))
+
     return form_data, metadata, events
 
 
diff --git a/backend/open_webui/utils/misc.py b/backend/open_webui/utils/misc.py
index e6b686071..bfa934c8b 100644
--- a/backend/open_webui/utils/misc.py
+++ b/backend/open_webui/utils/misc.py
@@ -330,6 +330,33 @@ def pop_system_message(messages: list[dict]) -> tuple[Optional[dict], list[dict]
     return get_system_message(messages), remove_system_message(messages)
 
 
+def merge_system_messages(messages: list[dict]) -> list[dict]:
+    """
+    Merge all system messages into one at position 0.
+
+    Some chat templates (e.g. Qwen) require exactly one system
+    message at the start.  Multiple pipeline stages may each
+    insert their own system message; this function consolidates
+    them.
+    """
+    system_contents: list[str] = []
+    other_messages: list[dict] = []
+
+    for message in messages:
+        if message.get('role') == 'system':
+            content = get_content_from_message(message)
+            if content:
+                system_contents.append(content)
+        else:
+            other_messages.append(message)
+
+    if not system_contents:
+        return other_messages
+
+    merged = {'role': 'system', 'content': '\n'.join(system_contents)}
+    return [merged, *other_messages]
+
+
 def update_message_content(message: dict, content: str, append: bool = True) -> dict:
     if isinstance(message['content'], list):
         for item in message['content']: