diff --git a/docs/api/plugin-development.md b/docs/api/plugin-development.md
index 65895b9..7e3a390 100644
--- a/docs/api/plugin-development.md
+++ b/docs/api/plugin-development.md
@@ -176,10 +176,12 @@ type ComplexTool interface {
 }
 
 type ToolProgress struct {
-    ExecutionID string  `json:"execution_id"`
-    Status      string  `json:"status"`   // running / completed / failed / cancelled
-    Progress    float64 `json:"progress"` // 0.0 ~ 1.0
-    Message     string  `json:"message,omitempty"`
+    ExecutionID string      `json:"execution_id"`
+    Status      string      `json:"status"`   // running / completed / failed / cancelled
+    Progress    float64     `json:"progress"` // 0.0 ~ 1.0
+    Message     string      `json:"message,omitempty"`
+    Error       string      `json:"error,omitempty"`
+    Result      *ToolResult `json:"result,omitempty"`
 }
 ```