kit初版，模型引入,agent优化

art-agent/backend/app/agent/tools.py

@@ -38,20 +38,27 @@ async def execute_tool(
     tool_name: str,
     arguments: dict,
     ref_image_url: str | None = None,
+    image_model: str | None = None,
 ) -> dict:
     """执行工具调用，返回结果。"""
     if tool_name == "generate_image":
         prompt = arguments["prompt"]
         num_images = arguments.get("num_images", 1)
-        image_urls = await generate_images(
+        result = await generate_images(
             prompt=prompt,
             num_images=num_images,
             ref_image_url=ref_image_url,
+            model_id=image_model,
         )
+        valid_urls = [u for u in result.urls if not u.startswith("[")]
+        errors = [u for u in result.urls if u.startswith("[")]
         return {
-            "success": True,
-            "images": image_urls,
+            "success": len(valid_urls) > 0,
+            "images": valid_urls,
+            "errors": errors,
             "prompt_used": prompt,
+            "model_name": result.model_name,
+            "model_id": result.model_id,
         }
 
     return {"success": False, "error": f"未知工具: {tool_name}"}