diff --git a/web/app/components/sub-graph/hooks/use-sub-graph-init.ts b/web/app/components/sub-graph/hooks/use-sub-graph-init.ts
index 68d1e1be20..84ee9abd9a 100644
--- a/web/app/components/sub-graph/hooks/use-sub-graph-init.ts
+++ b/web/app/components/sub-graph/hooks/use-sub-graph-init.ts
@@ -3,6 +3,7 @@ import type { LLMNodeType } from '@/app/components/workflow/nodes/llm/types'
 import type { StartNodeType } from '@/app/components/workflow/nodes/start/types'
 import type { Edge, Node, ValueSelector } from '@/app/components/workflow/types'
 import { useMemo } from 'react'
+import { Type } from '@/app/components/workflow/nodes/llm/types'
 import { BlockEnum, PromptRole } from '@/app/components/workflow/types'
 import { AppModeEnum } from '@/types/app'
 
@@ -12,6 +13,7 @@ export const SUBGRAPH_LLM_NODE_ID = 'subgraph-llm'
 export const getSubGraphInitialNodes = (
   sourceVariable: ValueSelector,
   agentName: string,
+  paramKey: string,
 ): Node[] => {
   const sourceVarName = sourceVariable.length > 1
     ? sourceVariable.slice(1).join('.')
@@ -60,6 +62,19 @@ export const getSubGraphInitialNodes = (
       vision: {
         enabled: false,
       },
+      structured_output_enabled: true,
+      structured_output: {
+        schema: {
+          type: Type.object,
+          properties: {
+            [paramKey]: {
+              type: Type.string,
+            },
+          },
+          required: [paramKey],
+          additionalProperties: false,
+        },
+      },
     },
   }
 
@@ -84,11 +99,11 @@ export const getSubGraphInitialEdges = (): Edge[] => {
 }
 
 export const useSubGraphInit = (props: SubGraphProps) => {
-  const { sourceVariable, agentName } = props
+  const { sourceVariable, agentName, paramKey } = props
 
   const initialNodes = useMemo((): Node[] => {
-    return getSubGraphInitialNodes(sourceVariable, agentName)
-  }, [sourceVariable, agentName])
+    return getSubGraphInitialNodes(sourceVariable, agentName, paramKey)
+  }, [sourceVariable, agentName, paramKey])
 
   const initialEdges = useMemo((): Edge[] => {
     return getSubGraphInitialEdges()
diff --git a/web/app/components/workflow/nodes/tool/components/mixed-variable-text-input/index.tsx b/web/app/components/workflow/nodes/tool/components/mixed-variable-text-input/index.tsx
index 1cc1480f6d..a340739c9c 100644
--- a/web/app/components/workflow/nodes/tool/components/mixed-variable-text-input/index.tsx
+++ b/web/app/components/workflow/nodes/tool/components/mixed-variable-text-input/index.tsx
@@ -16,6 +16,7 @@ import { useStoreApi } from 'reactflow'
 import PromptEditor from '@/app/components/base/prompt-editor'
 import { useNodesMetaData, useNodesSyncDraft } from '@/app/components/workflow/hooks'
 import { VarKindType as VarKindTypeEnum } from '@/app/components/workflow/nodes/_base/types'
+import { Type } from '@/app/components/workflow/nodes/llm/types'
 import { useStore } from '@/app/components/workflow/store'
 import { BlockEnum } from '@/app/components/workflow/types'
 import { generateNewNode, getNodeCustomTypeByNodeDataType } from '@/app/components/workflow/utils'
@@ -163,6 +164,19 @@ const MixedVariableTextInput = ({
             title: defaultValue.title,
             desc: defaultValue.desc || '',
             parent_node_id: toolNodeId,
+            structured_output_enabled: true,
+            structured_output: {
+              schema: {
+                type: Type.object,
+                properties: {
+                  [paramKey]: {
+                    type: Type.string,
+                  },
+                },
+                required: [paramKey],
+                additionalProperties: false,
+              },
+            },
           },
           position: {
             x: 0,
@@ -175,7 +189,12 @@ const MixedVariableTextInput = ({
       }
     }
 
-    onChange(newValue, VarKindTypeEnum.mention, DEFAULT_MENTION_CONFIG)
+    const mentionConfigWithOutputSelector: MentionConfig = {
+      ...DEFAULT_MENTION_CONFIG,
+      extractor_node_id: toolNodeId && paramKey ? `${toolNodeId}_ext_${paramKey}` : '',
+      output_selector: paramKey ? ['structured_output', paramKey] : [],
+    }
+    onChange(newValue, VarKindTypeEnum.mention, mentionConfigWithOutputSelector)
     setControlPromptEditorRerenderKey(Date.now())
   }, [handleSyncWorkflowDraft, nodesMetaDataMap, onChange, paramKey, reactFlowStore, setControlPromptEditorRerenderKey, toolNodeId, value])
 
diff --git a/web/app/components/workflow/nodes/tool/components/sub-graph-modal/index.tsx b/web/app/components/workflow/nodes/tool/components/sub-graph-modal/index.tsx
index 373b3153a1..d052fba728 100644
--- a/web/app/components/workflow/nodes/tool/components/sub-graph-modal/index.tsx
+++ b/web/app/components/workflow/nodes/tool/components/sub-graph-modal/index.tsx
@@ -47,13 +47,15 @@ const SubGraphModal: FC<SubGraphModalProps> = ({
     const current = toolParam?.mention_config
     const rawSelector = Array.isArray(current?.output_selector) ? current!.output_selector : []
     const outputSelector = rawSelector[0] === extractorNodeId ? rawSelector.slice(1) : rawSelector
+    const defaultOutputSelector = ['structured_output', paramKey]
+
     return {
       extractor_node_id: current?.extractor_node_id || extractorNodeId,
-      output_selector: outputSelector,
+      output_selector: outputSelector.length > 0 ? outputSelector : defaultOutputSelector,
       null_strategy: current?.null_strategy || 'use_default',
       default_value: current?.default_value ?? '',
     }
-  }, [extractorNodeId, toolParam?.mention_config])
+  }, [extractorNodeId, paramKey, toolParam?.mention_config])
 
   const handleMentionConfigChange = useCallback((config: MentionConfig) => {
     const { getNodes, setNodes } = reactflowStore.getState()