fixed reasoning

backend/app/chat/service.py

@@ -148,6 +148,9 @@ class ChatService:
                 if event["type"] == "content":
                     content_parts.append(event["content"])
                     yield self._sse("token", {"content": event["content"]})
+                elif event["type"] == "error":
+                    yield self._sse("error", {"message": event.get("content", "LLM error")})
+                    return
                 elif event["type"] == "tool_calls":
                     tool_calls = event["tool_calls"]
 
@@ -193,8 +196,20 @@ class ChatService:
                 continue
 
             final_content = "".join(content_parts)
-            if final_content:
-                self._save_message(session_id, "assistant", final_content)
+            if not final_content.strip():
+                yield self._sse(
+                    "error",
+                    {
+                        "message": (
+                            "Модель не вернула текст. Проверь OPENROUTER_MODEL: "
+                            "нужна поддержка tool calling или отключи OPENROUTER_TOOLS_ENABLED=false. "
+                            "Для памяти можно задать MEMORY_EXTRACT_MODEL=deepseek/deepseek-chat."
+                        ),
+                    },
+                )
+                return
+
+            self._save_message(session_id, "assistant", final_content)
 
             memory_meta: dict[str, Any] = {}
             if get_settings().memory_auto_extract: