diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index cc46184d4a..2b42c028b1 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -2157,10 +2157,13 @@ async def convert_url_images_to_base64(form_data, user=None):
     return form_data
 
 
+MESSAGE_REPLAY_KEYS = ('id', 'role', 'content', 'output', 'files', 'contextSummary', 'usage', 'model')
+
+
 async def load_messages_from_db(chat_id: str, message_id: str) -> Optional[list[dict]]:
     """
     Load the message chain from DB up to message_id,
-    keeping only LLM-relevant fields (role, content, output).
+    keeping only fields needed to rebuild the LLM payload.
     """
     messages_map = await Chats.get_messages_map_by_chat_id(chat_id)
     if not messages_map:
@@ -2170,10 +2173,7 @@ async def load_messages_from_db(chat_id: str, message_id: str) -> Optional[list[
     if not db_messages:
         return None
 
-    return [
-        {k: v for k, v in msg.items() if k in ('id', 'role', 'content', 'output', 'files', 'contextSummary', 'usage')}
-        for msg in db_messages
-    ]
+    return [{k: v for k, v in msg.items() if k in MESSAGE_REPLAY_KEYS} for msg in db_messages]
 
 
 def get_reasoning_format(model: dict) -> str | None:
@@ -2194,6 +2194,13 @@ def get_reasoning_format(model: dict) -> str | None:
     return None
 
 
+def strip_reasoning_details(output: list) -> list:
+    return [
+        {key: value for key, value in item.items() if key != 'reasoning_details'} if isinstance(item, dict) else item
+        for item in output
+    ]
+
+
 def process_messages_with_output(
     messages: list[dict],
     reasoning_format: str | None = None,
@@ -2220,7 +2227,7 @@ def process_messages_with_output(
                 continue
 
         clean_message = dict(message)
-        for key in ('id', 'files', 'output', 'contextSummary', 'context_summary', 'usage'):
+        for key in ('id', 'files', 'output', 'model', 'contextSummary', 'context_summary', 'usage'):
             clean_message.pop(key, None)
         processed.append(clean_message)
 
@@ -2416,13 +2423,7 @@ async def process_chat_payload(request, form_data, user, metadata, model):
             if assistant_message_id:
                 assistant_message = await Chats.get_message_by_id_and_message_id(chat_id, assistant_message_id)
                 if assistant_message and (assistant_message.get('content') or assistant_message.get('output')):
-                    db_messages.append(
-                        {
-                            k: v
-                            for k, v in assistant_message.items()
-                            if k in ('id', 'role', 'content', 'output', 'files', 'contextSummary', 'usage')
-                        }
-                    )
+                    db_messages.append({k: v for k, v in assistant_message.items() if k in MESSAGE_REPLAY_KEYS})
 
             system_message = get_system_message(form_data.get('messages', []))
             form_data['messages'] = [system_message, *db_messages] if system_message else db_messages
@@ -2486,6 +2487,13 @@ async def process_chat_payload(request, form_data, user, metadata, model):
             log.exception('Context compaction failed; continuing with full chat history')
 
     # Process messages with OR-aligned output items for clean LLM messages
+    for message in form_data.get('messages', []):
+        output = message.get('output')
+        # reasoning_details can be model/provider-bound, so only replay them
+        # for output produced by the same model.
+        if message.get('role') == 'assistant' and message.get('model') != model['id'] and isinstance(output, list):
+            message['output'] = strip_reasoning_details(output)
+
     form_data['messages'] = process_messages_with_output(
         form_data.get('messages', []),
         reasoning_format=get_reasoning_format(model),
@@ -3365,13 +3373,18 @@ async def drain_approved_tool_calls(request, form_data, user, model, metadata) -
         if db_messages:
             assistant_message = await Chats.get_message_by_id_and_message_id(chat_id, message_id)
             if assistant_message:
-                db_messages.append(
-                    {
-                        k: v
-                        for k, v in assistant_message.items()
-                        if k in ('id', 'role', 'content', 'output', 'files', 'contextSummary', 'usage')
-                    }
-                )
+                db_messages.append({k: v for k, v in assistant_message.items() if k in MESSAGE_REPLAY_KEYS})
+            for message in db_messages:
+                output = message.get('output')
+                # reasoning_details can be model/provider-bound, so only replay them
+                # for output produced by the same model.
+                if (
+                    message.get('role') == 'assistant'
+                    and message.get('model') != model['id']
+                    and isinstance(output, list)
+                ):
+                    message['output'] = strip_reasoning_details(output)
+
             form_data['messages'] = process_messages_with_output(
                 db_messages,
                 reasoning_format=get_reasoning_format(model),