diff --git a/common/util/mapping.go b/common/util/mapping.go
index d91d22a..11be623 100644
--- a/common/util/mapping.go
+++ b/common/util/mapping.go
@@ -1,6 +1,7 @@
 package util
 
 import (
+	"encoding/json"
 	"fmt"
 	"strings"
 
@@ -114,33 +115,18 @@ func buildAttachment(tmpl map[string]any, url string) map[string]any {
 		return nil
 	}
 
-	body := gconv.Map(tmpl["body"])
-	fillEmptyInPlace(body, url)
+	// 深拷贝模板
+	b, _ := json.Marshal(tmpl)
+	str := string(b)
+	str = strings.ReplaceAll(str, `"{{url}}"`, `"`+url+`"`)
 
-	result := map[string]any{
-		"type": typ,
-		typ:    body,
-	}
-	if role, ok := tmpl["role"].(string); ok && role != "" {
-		result["role"] = role
-	}
+	var result map[string]any
+	_ = json.Unmarshal([]byte(str), &result)
+	delete(result, "type")
+	result["type"] = typ
 	return result
 }
 
-// fillEmptyInPlace 递归填充空字符串
-func fillEmptyInPlace(m map[string]any, value string) {
-	for k, v := range m {
-		switch vv := v.(type) {
-		case string:
-			if vv == "" {
-				m[k] = value
-			}
-		case map[string]any:
-			fillEmptyInPlace(vv, value)
-		}
-	}
-}
-
 // ======================== 系统提示词合并 ========================
 
 // MergeSystemPrompt 将系统提示词和技能内容拼接到 system role 的 content 中