diff --git a/web/src/pages/agent/canvas/node/card.tsx b/web/src/pages/agent/canvas/node/card.tsx
index 19fe5623f..642504714 100644
--- a/web/src/pages/agent/canvas/node/card.tsx
+++ b/web/src/pages/agent/canvas/node/card.tsx
@@ -61,15 +61,17 @@ export function CardWithForm() {
 
 type LabelCardProps = {
   className?: string;
-} & PropsWithChildren;
+} & PropsWithChildren &
+  React.HTMLAttributes<HTMLElement>;
 
-export function LabelCard({ children, className }: LabelCardProps) {
+export function LabelCard({ children, className, ...props }: LabelCardProps) {
   return (
     <div
       className={cn(
         'bg-bg-card rounded-sm p-1 text-text-secondary text-xs',
         className,
       )}
+      {...props}
     >
       {children}
     </div>
diff --git a/web/src/pages/agent/form/components/query-variable.tsx b/web/src/pages/agent/form/components/query-variable.tsx
index 327e6ce6b..fec842171 100644
--- a/web/src/pages/agent/form/components/query-variable.tsx
+++ b/web/src/pages/agent/form/components/query-variable.tsx
@@ -56,6 +56,7 @@ export function QueryVariable({
               options={finalOptions}
               {...field}
               // allowClear
+              type={type}
             ></GroupedSelectWithSecondaryMenu>
           </FormControl>
           <FormMessage />
diff --git a/web/src/pages/agent/form/components/select-with-secondary-menu.tsx b/web/src/pages/agent/form/components/select-with-secondary-menu.tsx
index d8f336d51..5aff0db4b 100644
--- a/web/src/pages/agent/form/components/select-with-secondary-menu.tsx
+++ b/web/src/pages/agent/form/components/select-with-secondary-menu.tsx
@@ -23,6 +23,7 @@ import { ChevronDownIcon, XIcon } from 'lucide-react';
 import * as React from 'react';
 import { useCallback } from 'react';
 import { useTranslation } from 'react-i18next';
+import { VariableType } from '../../constant';
 import {
   useFilterStructuredOutputByValue,
   useFindAgentStructuredOutputLabel,
@@ -52,6 +53,7 @@ interface GroupedSelectWithSecondaryMenuProps {
   value?: string;
   onChange?: (value: string) => void;
   placeholder?: string;
+  type?: VariableType;
 }
 
 export function GroupedSelectWithSecondaryMenu({
@@ -59,6 +61,7 @@ export function GroupedSelectWithSecondaryMenu({
   value,
   onChange,
   placeholder,
+  type,
 }: GroupedSelectWithSecondaryMenuProps) {
   const { t } = useTranslation();
   const [open, setOpen] = React.useState(false);
@@ -69,6 +72,7 @@ export function GroupedSelectWithSecondaryMenu({
 
   // Find the label of the selected item
   const flattenedOptions = options.flatMap((g) => g.options);
+
   let selectedItem = flattenedOptions
     .flatMap((o) => [o, ...(o.children || [])])
     .find((o) => o.value === value);
@@ -140,7 +144,7 @@ export function GroupedSelectWithSecondaryMenu({
       <PopoverContent className="p-0" align="start">
         <Command value={value}>
           <CommandInput placeholder="Search..." />
-          <CommandList className="overflow-visible">
+          <CommandList className="overflow-auto">
             {options.map((group, idx) => (
               <CommandGroup key={idx} heading={group.label}>
                 {group.options.map((option) => {
@@ -159,6 +163,7 @@ export function GroupedSelectWithSecondaryMenu({
                         data={option}
                         click={handleSecondaryMenuClick}
                         filteredStructuredOutput={filteredStructuredOutput}
+                        type={type}
                       ></StructuredOutputSecondaryMenu>
                     );
                   }
diff --git a/web/src/pages/agent/form/components/structured-output-secondary-menu.tsx b/web/src/pages/agent/form/components/structured-output-secondary-menu.tsx
index a003bb33a..a75d542d8 100644
--- a/web/src/pages/agent/form/components/structured-output-secondary-menu.tsx
+++ b/web/src/pages/agent/form/components/structured-output-secondary-menu.tsx
@@ -8,6 +8,7 @@ import { cn } from '@/lib/utils';
 import { get, isPlainObject } from 'lodash';
 import { ChevronRight } from 'lucide-react';
 import { PropsWithChildren, ReactNode, useCallback } from 'react';
+import { VariableType } from '../../constant';
 
 type DataItem = { label: ReactNode; value: string; parentLabel?: ReactNode };
 
@@ -15,12 +16,24 @@ type StructuredOutputSecondaryMenuProps = {
   data: DataItem;
   click(option: { label: ReactNode; value: string }): void;
   filteredStructuredOutput: JSONSchema;
+  type?: VariableType;
 } & PropsWithChildren;
 export function StructuredOutputSecondaryMenu({
   data,
   click,
   filteredStructuredOutput,
+  type,
 }: StructuredOutputSecondaryMenuProps) {
+  const handleSubMenuClick = useCallback(
+    (option: { label: ReactNode; value: string }, dataType?: string) => () => {
+      // The query variable of the iteration operator can only select array type data.
+      if ((type && type === dataType) || !type) {
+        click(option);
+      }
+    },
+    [click, type],
+  );
+
   const renderAgentStructuredOutput = useCallback(
     (values: any, option: { label: ReactNode; value: string }) => {
       if (isPlainObject(values) && 'properties' in values) {
@@ -37,7 +50,7 @@ export function StructuredOutputSecondaryMenu({
               return (
                 <li key={key} className="pl-1">
                   <div
-                    onClick={() => click(nextOption)}
+                    onClick={handleSubMenuClick(nextOption, dataType)}
                     className="hover:bg-bg-card p-1 text-text-primary rounded-sm flex justify-between"
                   >
                     {key}
@@ -54,13 +67,16 @@ export function StructuredOutputSecondaryMenu({
 
       return <div></div>;
     },
-    [click],
+    [handleSubMenuClick],
   );
 
   return (
     <HoverCard key={data.value} openDelay={100} closeDelay={100}>
       <HoverCardTrigger asChild>
-        <li className="hover:bg-bg-card py-1 px-2 text-text-primary rounded-sm text-sm flex justify-between items-center">
+        <li
+          onClick={() => click(data)}
+          className="hover:bg-bg-card py-1 px-2 text-text-primary rounded-sm text-sm flex justify-between items-center"
+        >
           {data.label} <ChevronRight className="size-3.5 text-text-secondary" />
         </li>
       </HoverCardTrigger>
diff --git a/web/src/pages/agent/utils/filter-agent-structured-output.ts b/web/src/pages/agent/utils/filter-agent-structured-output.ts
index 3f51158e9..56e3ec21f 100644
--- a/web/src/pages/agent/utils/filter-agent-structured-output.ts
+++ b/web/src/pages/agent/utils/filter-agent-structured-output.ts
@@ -2,6 +2,42 @@ import { JSONSchema } from '@/components/jsonjoy-builder';
 import { Operator } from '@/constants/agent';
 import { isPlainObject } from 'lodash';
 
+// Loop operators can only accept variables of type list.
+
+// Recursively traverse the JSON schema, keeping attributes with type "array" and discarding others.
+
+export function filterLoopOperatorInput(
+  structuredOutput: JSONSchema,
+  path = [],
+) {
+  if (typeof structuredOutput === 'boolean') {
+    return structuredOutput;
+  }
+  if (
+    structuredOutput.properties &&
+    isPlainObject(structuredOutput.properties)
+  ) {
+    const properties = Object.entries({
+      ...structuredOutput.properties,
+    }).reduce(
+      (pre, [key, value]) => {
+        if (
+          typeof value !== 'boolean' &&
+          (value.type === 'array' || hasArrayChild(value))
+        ) {
+          pre[key] = filterLoopOperatorInput(value, path);
+        }
+        return pre;
+      },
+      {} as Record<string, JSONSchema>,
+    );
+
+    return { ...structuredOutput, properties };
+  }
+
+  return structuredOutput;
+}
+
 export function filterAgentStructuredOutput(
   structuredOutput: JSONSchema,
   operator?: string,
@@ -13,32 +49,39 @@ export function filterAgentStructuredOutput(
     structuredOutput.properties &&
     isPlainObject(structuredOutput.properties)
   ) {
-    const filterByPredicate = (predicate: (value: JSONSchema) => boolean) => {
-      const properties = Object.entries({
-        ...structuredOutput.properties,
-      }).reduce(
-        (pre, [key, value]) => {
-          if (predicate(value)) {
-            pre[key] = value;
-          }
-          return pre;
-        },
-        {} as Record<string, JSONSchema>,
-      );
-
-      return { ...structuredOutput, properties };
-    };
-
     if (operator === Operator.Iteration) {
-      return filterByPredicate(
-        (value) => typeof value !== 'boolean' && value.type === 'array',
-      );
-    } else {
-      return filterByPredicate(
-        (value) => typeof value !== 'boolean' && value.type !== 'array',
-      );
+      return filterLoopOperatorInput(structuredOutput);
     }
+
+    return structuredOutput;
   }
 
   return structuredOutput;
 }
+
+export function hasArrayChild(data: Record<string, any> | Array<any>) {
+  if (Array.isArray(data)) {
+    for (const value of data) {
+      if (isPlainObject(value) && value.type === 'array') {
+        return true;
+      }
+      if (hasArrayChild(value)) {
+        return true;
+      }
+    }
+  }
+
+  if (isPlainObject(data)) {
+    for (const value of Object.values(data)) {
+      if (isPlainObject(value) && value.type === 'array') {
+        return true;
+      }
+
+      if (hasArrayChild(value)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}