diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index fe36d78d7b..88738df7ec 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -4145,12 +4145,14 @@ async def streaming_chat_response_handler(response, ctx):
                         if delta_count >= delta_chunk_size:
                             await flush_pending_delta_data(delta_chunk_size)
 
+                    filter_extra_params = {'__body__': form_data, **extra_params} if filter_functions else None
+
                     async for line in response.body_iterator:
                         line = line.decode('utf-8', 'replace') if isinstance(line, bytes) else line
                         data = line
 
                         # Skip empty lines
-                        if not data.strip():
+                        if not data or data.isspace():
                             continue
 
                         # "data:" is the prefix for each event
@@ -4178,20 +4180,21 @@ async def streaming_chat_response_handler(response, ctx):
                                 pass
                             continue
 
-                        # Remove the prefix
-                        data = data[len('data:') :].strip()
+                        # Remove the "data:" prefix
+                        data = data[5:].strip()
 
                         try:
                             data = json.loads(data)
 
-                            data, _ = await process_filter_functions(
-                                request=request,
-                                filter_context=filter_context,
-                                filter_functions=filter_functions,
-                                filter_type='stream',
-                                form_data=data,
-                                extra_params={'__body__': form_data, **extra_params},
-                            )
+                            if filter_functions:
+                                data, _ = await process_filter_functions(
+                                    request=request,
+                                    filter_context=filter_context,
+                                    filter_functions=filter_functions,
+                                    filter_type='stream',
+                                    form_data=data,
+                                    extra_params=filter_extra_params,
+                                )
 
                             if data:
                                 if 'event' in data and not getattr(request.state, 'direct', False):
@@ -4433,7 +4436,12 @@ async def streaming_chat_response_handler(response, ctx):
                                             }
                                             delta_type = 'tool_call'
 
-                                    image_urls = await get_image_urls(delta.get('images', []), request, metadata, user)
+                                    delta_images = delta.get('images')
+                                    image_urls = (
+                                        await get_image_urls(delta_images, request, metadata, user)
+                                        if delta_images
+                                        else []
+                                    )
                                     if image_urls:
                                         image_file_list = [{'type': 'image', 'url': url} for url in image_urls]
                                         message_files = image_file_list
diff --git a/backend/open_webui/utils/misc.py b/backend/open_webui/utils/misc.py
index ddef7b91c2..8b867ff2d3 100644
--- a/backend/open_webui/utils/misc.py
+++ b/backend/open_webui/utils/misc.py
@@ -663,9 +663,9 @@ def strip_empty_content_blocks(messages: list[dict]) -> list[dict]:
     return messages
 
 
-def openai_chat_message_template(model: str):
+def openai_chat_message_template(model: str, message_id: str | None = None):
     return {
-        'id': f'{model}-{str(uuid.uuid4())}',
+        'id': message_id if message_id else f'{model}-{str(uuid.uuid4())}',
         'created': int(time.time()),
         'model': model,
         'choices': [{'index': 0, 'logprobs': None, 'finish_reason': None}],
@@ -678,8 +678,9 @@ def openai_chat_chunk_message_template(
     reasoning_content: str | None = None,
     tool_calls: list[dict | None] = None,
     usage: dict | None = None,
+    message_id: str | None = None,
 ) -> dict:
-    template = openai_chat_message_template(model)
+    template = openai_chat_message_template(model, message_id)
     template['object'] = 'chat.completion.chunk'
 
     template['choices'][0]['index'] = 0
diff --git a/backend/open_webui/utils/response.py b/backend/open_webui/utils/response.py
index 8b0214f6c8..463ce499a7 100644
--- a/backend/open_webui/utils/response.py
+++ b/backend/open_webui/utils/response.py
@@ -66,6 +66,8 @@ USAGE_COST_KEYS = {
     'completion_cost',
 }
 
+USAGE_SUMMABLE_KEYS = USAGE_TOKEN_KEYS | USAGE_COST_KEYS
+
 USAGE_DETAIL_KEYS = {
     'prompt_tokens_details',
     'completion_tokens_details',
@@ -115,7 +117,7 @@ def merge_usage(current: dict | None, incoming: dict | None) -> dict:
 
     result = {**current_usage, **incoming_usage}
 
-    for key in USAGE_TOKEN_KEYS | USAGE_COST_KEYS:
+    for key in USAGE_SUMMABLE_KEYS:
         if key in current_usage or key in incoming_usage:
             current_value = current_usage.get(key, 0)
             incoming_value = incoming_usage.get(key, 0)
@@ -238,9 +240,10 @@ async def convert_streaming_response_ollama_to_openai(ollama_streaming_response)
         data = json.loads(data)
 
         model = data.get('model', 'ollama')
-        message_content = data.get('message', {}).get('content', None)
-        reasoning_content = data.get('message', {}).get('thinking', None)
-        tool_calls = data.get('message', {}).get('tool_calls', None)
+        message = data.get('message') or {}
+        message_content = message.get('content', None)
+        reasoning_content = message.get('thinking', None)
+        tool_calls = message.get('tool_calls', None)
         openai_tool_calls = None
 
         if tool_calls:
@@ -253,8 +256,9 @@ async def convert_streaming_response_ollama_to_openai(ollama_streaming_response)
         if done:
             usage = convert_ollama_usage_to_openai(data)
 
-        data = openai_chat_chunk_message_template(model, message_content, reasoning_content, openai_tool_calls, usage)
-        data['id'] = completion_id
+        data = openai_chat_chunk_message_template(
+            model, message_content, reasoning_content, openai_tool_calls, usage, message_id=completion_id
+        )
 
         # First chunk must carry delta.role (OpenAI spec).
         if first: