更新图形生成工具，优化返回格式并添加新功能

app/service/fashion_agent/service.py

@@ -6,7 +6,7 @@ from langgraph.stream import ProtocolEvent, StreamChannel, StreamTransformer
 from app.service.fashion_agent.main_agent import build_main_graph
 from langgraph.prebuilt import ToolCallTransformer
 from typing import AsyncGenerator, TypedDict
-from langchain_core.messages import HumanMessage
+from langchain_core.messages import HumanMessage, ToolMessage
 from app.schemas.fashion_agent import FashionAgentRequest
 
 logger = logging.getLogger()
@@ -71,6 +71,8 @@ class FashionAgentService:
 
                     data["tool_name"] = tool_name
 
+                    if isinstance(data["output"], ToolMessage):
+                        data["output"] = json.loads(data["output"].content)
                 response_event = {"event_type": "tool", "data": data}
                 yield f"data: {json.dumps(response_event, ensure_ascii=False)}\n\n"