diff --git a/src/helpers/rpc/performAction.ts b/src/helpers/rpc/performAction.ts
index 78ab45a..26437f6 100644
--- a/src/helpers/rpc/performAction.ts
+++ b/src/helpers/rpc/performAction.ts
@@ -140,7 +140,7 @@ function createOperateTool(
     console.log("operateTool", action);
     switch (action.name) {
       case "scroll":
-        await scroll(domActions, action?.args?.value ?? "down");
+        await scroll(domActions, action.args.value);
         break;
       case "wait":
         await sleep(3000);
diff --git a/src/helpers/vision-agent/tools.ts b/src/helpers/vision-agent/tools.ts
index 9059170..569afab 100644
--- a/src/helpers/vision-agent/tools.ts
+++ b/src/helpers/vision-agent/tools.ts
@@ -55,11 +55,9 @@ export const scrollSchema = z.object({
       'Scroll the page to see the other parts. Use "up" or "down" to scroll 2/3 of height of the window. Use "top" or "bottom" to quickly scroll to the top or bottom of the page.',
     )
     .optional(),
-  args: z
-    .object({
-      value: z.string(),
-    })
-    .optional(),
+  args: z.object({
+    value: z.string(),
+  }),
 });
 
 export const waitSchema = z.object({