From b6d861645b11090b82dc3db6dd58db07dcbb2aac Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Thu, 5 Nov 2026 14:27:27 +0100
Subject: [PATCH] fix: chat stops working with Ollama after a tool call with
 broken arguments (#33697)

A tool call whose arguments were cut off, rejected before it ran or sent empty made every later message with an Ollama model fail, so the chat stayed stuck until that message was edited or removed. Such calls are now sent to Ollama with empty arguments and the conversation continues.

Fixes #33671
---
 backend/open_webui/utils/payload.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/backend/open_webui/utils/payload.py b/backend/open_webui/utils/payload.py
index f1befc53a8..962c98696f 100644
--- a/backend/open_webui/utils/payload.py
+++ b/backend/open_webui/utils/payload.py
@@ -328,12 +328,19 @@ def convert_chat_completions_messages_to_ollama(messages: list[dict]) -> list[di
             # If tool calls are present, add them to the message
             ollama_tool_calls = []
             for tool_call in tool_calls:
+                arguments = tool_call.get('function', {}).get('arguments')
+                if isinstance(arguments, str):
+                    try:
+                        arguments = JSONCodec.loads(arguments)
+                    except JSONCodec.JSONDecodeError:
+                        arguments = {}
+
                 ollama_tool_call = {
                     'index': tool_call.get('index', 0),
                     'id': tool_call.get('id', None),
                     'function': {
                         'name': tool_call.get('function', {}).get('name', ''),
-                        'arguments': JSONCodec.loads(tool_call.get('function', {}).get('arguments', {})),
+                        'arguments': arguments if isinstance(arguments, dict) else {},
                     },
                 }
                 ollama_tool_calls.append(ollama_tool_call)