diff --git a/backend/python/app/api/chat_service.py b/backend/python/app/api/chat_service.py
index 7a83622..b94522d 100644
--- a/backend/python/app/api/chat_service.py
+++ b/backend/python/app/api/chat_service.py
@@ -1612,6 +1612,20 @@ async def _send_message_core(
             except Exception:
                 pass
 
+            # Phase 1: Bill tokens on stream completion
+            try:
+                _pt = prompt_tokens if "prompt_tokens" in dir() else 0
+                _ct = completion_tokens if "completion_tokens" in dir() else 0
+                _uid = user_id if "user_id" in dir() else "unknown"
+                if _pt or _ct:
+                    import asyncio
+                    asyncio.create_task(_bill_tokens(
+                        _uid, _pt, _ct,
+                        ai_model if "ai_model" in dir() else "unknown",
+                        conv_id))
+            except Exception:
+                pass
+
         return {