diff --git a/backend/src/inference.py b/backend/src/inference.py
index bb16f55..5860fff 100644
--- a/backend/src/inference.py
+++ b/backend/src/inference.py
@@ -72,6 +72,7 @@ model_cache = {}
 last_model_file = None
 last_model_instance = None
 
+# Wrap an async function in a queue to send it safely from another thread
 def safe_queue(callback):
     queue = asyncio.Queue()
     loop = asyncio.get_running_loop()
@@ -348,9 +349,7 @@ async def openrouter_chat_completion(app, messages, model, tools=[], opts={}, ag
 
             # OpenAI format streams tool calls in parts
             # We could, but I won't assume any tool call is complete until the message is over
-            # TODO: tool_call_by_index = {}
             tool_calls = []
-            last_tool_call = None
 
             async for event in stream_response:
                 if agent_run and agent_run.cancelled:
@@ -368,24 +367,18 @@ async def openrouter_chat_completion(app, messages, model, tools=[], opts={}, ag
                     if delta.tool_calls:
                         print("[openrouter] tool call:" + repr(delta.tool_calls)) 
                         for tc in delta.tool_calls:
-                            if not last_tool_call:
-                                last_tool_call = ToolCall(None, arguments="")
-                                tool_calls.append(last_tool_call)
+                            if tc.index >= len(tool_calls):
+                                tool_calls.append(ToolCall(tool_name="", arguments="", id=""))
+                            tool_call = tool_calls[tc.index]
 
                             if tc.id:
-                                if last_tool_call.id is None:
-                                    last_tool_call.id = tc.id
-                                elif last_tool_call.id != tc.id:
-                                    # New id = new tool
-                                    # TODO: WRONG! new id must append value to accumulating id. new index signals new tool
-                                    last_tool_call = ToolCall(None, arguments="", id=tc.id)
-                                    tool_calls.append(last_tool_call)
+                                tool_call.id += tc.id
 
                             if tc.function:
                                 if tc.function.name:
-                                    last_tool_call.tool_name = tc.function.name
+                                    tool_call.tool_name += tc.function.name
                                 if tc.function.arguments:
-                                    last_tool_call.arguments += tc.function.arguments
+                                    tool_call.arguments += tc.function.arguments
                 else:
                     print("[openrouter] no event choices: " + repr(event))