diff --git a/packages/shared-frontend-utils/src/formatUtil.test.ts b/packages/shared-frontend-utils/src/formatUtil.test.ts
index e9748b4ca0..d494126db5 100644
--- a/packages/shared-frontend-utils/src/formatUtil.test.ts
+++ b/packages/shared-frontend-utils/src/formatUtil.test.ts
@@ -1,7 +1,11 @@
 import { describe, expect, it } from 'vitest'
 
 import {
+  appendWorkflowJsonExt,
+  ensureWorkflowSuffix,
+  getFilenameDetails,
   getMediaTypeFromFilename,
+  getPathDetails,
   highlightQuery,
   isPreviewableMediaType,
   truncateFilename
@@ -198,6 +202,147 @@ describe('formatUtil', () => {
     })
   })
 
+  describe('getFilenameDetails', () => {
+    it('splits simple filenames into name and suffix', () => {
+      expect(getFilenameDetails('file.txt')).toEqual({
+        filename: 'file',
+        suffix: 'txt'
+      })
+    })
+
+    it('handles filenames with multiple dots', () => {
+      expect(getFilenameDetails('my.file.name.png')).toEqual({
+        filename: 'my.file.name',
+        suffix: 'png'
+      })
+    })
+
+    it('handles filenames without extension', () => {
+      expect(getFilenameDetails('README')).toEqual({
+        filename: 'README',
+        suffix: null
+      })
+    })
+
+    it('recognises .app.json as a compound extension', () => {
+      expect(getFilenameDetails('workflow.app.json')).toEqual({
+        filename: 'workflow',
+        suffix: 'app.json'
+      })
+    })
+
+    it('recognises .app.json case-insensitively', () => {
+      expect(getFilenameDetails('Workflow.APP.JSON')).toEqual({
+        filename: 'Workflow',
+        suffix: 'app.json'
+      })
+    })
+
+    it('handles regular .json files normally', () => {
+      expect(getFilenameDetails('workflow.json')).toEqual({
+        filename: 'workflow',
+        suffix: 'json'
+      })
+    })
+
+    it('treats bare .app.json as a dotfile without basename', () => {
+      expect(getFilenameDetails('.app.json')).toEqual({
+        filename: '.app',
+        suffix: 'json'
+      })
+    })
+  })
+
+  describe('getPathDetails', () => {
+    it('splits a path with .app.json extension', () => {
+      const result = getPathDetails('workflows/test.app.json')
+      expect(result).toEqual({
+        directory: 'workflows',
+        fullFilename: 'test.app.json',
+        filename: 'test',
+        suffix: 'app.json'
+      })
+    })
+
+    it('splits a path with .json extension', () => {
+      const result = getPathDetails('workflows/test.json')
+      expect(result).toEqual({
+        directory: 'workflows',
+        fullFilename: 'test.json',
+        filename: 'test',
+        suffix: 'json'
+      })
+    })
+  })
+
+  describe('appendWorkflowJsonExt', () => {
+    it('appends .app.json when isApp is true', () => {
+      expect(appendWorkflowJsonExt('test', true)).toBe('test.app.json')
+    })
+
+    it('appends .json when isApp is false', () => {
+      expect(appendWorkflowJsonExt('test', false)).toBe('test.json')
+    })
+
+    it('replaces .json with .app.json when isApp is true', () => {
+      expect(appendWorkflowJsonExt('test.json', true)).toBe('test.app.json')
+    })
+
+    it('replaces .app.json with .json when isApp is false', () => {
+      expect(appendWorkflowJsonExt('test.app.json', false)).toBe('test.json')
+    })
+
+    it('leaves .app.json unchanged when isApp is true', () => {
+      expect(appendWorkflowJsonExt('test.app.json', true)).toBe('test.app.json')
+    })
+
+    it('leaves .json unchanged when isApp is false', () => {
+      expect(appendWorkflowJsonExt('test.json', false)).toBe('test.json')
+    })
+
+    it('handles case-insensitive extensions', () => {
+      expect(appendWorkflowJsonExt('test.JSON', true)).toBe('test.app.json')
+      expect(appendWorkflowJsonExt('test.APP.JSON', false)).toBe('test.json')
+    })
+  })
+
+  describe('ensureWorkflowSuffix', () => {
+    it('appends suffix when missing', () => {
+      expect(ensureWorkflowSuffix('file', 'json')).toBe('file.json')
+    })
+
+    it('does not double-append when suffix already present', () => {
+      expect(ensureWorkflowSuffix('file.json', 'json')).toBe('file.json')
+    })
+
+    it('appends compound suffix when missing', () => {
+      expect(ensureWorkflowSuffix('file', 'app.json')).toBe('file.app.json')
+    })
+
+    it('does not double-append compound suffix', () => {
+      expect(ensureWorkflowSuffix('file.app.json', 'app.json')).toBe(
+        'file.app.json'
+      )
+    })
+
+    it('replaces .json with .app.json when suffix is app.json', () => {
+      expect(ensureWorkflowSuffix('file.json', 'app.json')).toBe(
+        'file.app.json'
+      )
+    })
+
+    it('replaces .app.json with .json when suffix is json', () => {
+      expect(ensureWorkflowSuffix('file.app.json', 'json')).toBe('file.json')
+    })
+
+    it('handles case-insensitive extension detection', () => {
+      expect(ensureWorkflowSuffix('file.JSON', 'json')).toBe('file.json')
+      expect(ensureWorkflowSuffix('file.APP.JSON', 'app.json')).toBe(
+        'file.app.json'
+      )
+    })
+  })
+
   describe('isPreviewableMediaType', () => {
     it('returns true for image/video/audio/3D', () => {
       expect(isPreviewableMediaType('image')).toBe(true)
diff --git a/packages/shared-frontend-utils/src/formatUtil.ts b/packages/shared-frontend-utils/src/formatUtil.ts
index bb9d2ff18e..74845409fa 100644
--- a/packages/shared-frontend-utils/src/formatUtil.ts
+++ b/packages/shared-frontend-utils/src/formatUtil.ts
@@ -26,13 +26,44 @@ export function formatCamelCase(str: string): string {
   return processedWords.join(' ')
 }
 
+// Metadata cannot be associated with workflows, so extension encodes the mode.
+const JSON_SUFFIX = 'json'
+const APP_JSON_SUFFIX = `app.${JSON_SUFFIX}`
+const JSON_EXT = `.${JSON_SUFFIX}`
+const APP_JSON_EXT = `.${APP_JSON_SUFFIX}`
+
 export function appendJsonExt(path: string) {
-  if (!path.toLowerCase().endsWith('.json')) {
-    path += '.json'
+  if (!path.toLowerCase().endsWith(JSON_EXT)) {
+    path += JSON_EXT
   }
   return path
 }
 
+export type WorkflowSuffix = typeof JSON_SUFFIX | typeof APP_JSON_SUFFIX
+
+export function getWorkflowSuffix(
+  suffix: string | null | undefined
+): WorkflowSuffix {
+  return suffix === APP_JSON_SUFFIX ? APP_JSON_SUFFIX : JSON_SUFFIX
+}
+
+export function appendWorkflowJsonExt(path: string, isApp: boolean): string {
+  return ensureWorkflowSuffix(path, isApp ? APP_JSON_SUFFIX : JSON_SUFFIX)
+}
+
+export function ensureWorkflowSuffix(
+  name: string,
+  suffix: WorkflowSuffix
+): string {
+  const lower = name.toLowerCase()
+  if (lower.endsWith(APP_JSON_EXT)) {
+    name = name.slice(0, -APP_JSON_EXT.length)
+  } else if (lower.endsWith(JSON_EXT)) {
+    name = name.slice(0, -JSON_EXT.length)
+  }
+  return name + '.' + suffix
+}
+
 export function highlightQuery(
   text: string,
   query: string,
@@ -96,19 +127,27 @@ export function formatCommitHash(value: string): string {
 
 /**
  * Returns various filename components.
+ * Recognises compound extensions like `.app.json`.
  * Example:
- * - fullFilename: 'file.txt'
- * - filename: 'file'
- * - suffix: 'txt'
+ * - fullFilename: 'file.txt'       → { filename: 'file',  suffix: 'txt' }
+ * - fullFilename: 'file.app.json'  → { filename: 'file',  suffix: 'app.json' }
  */
 export function getFilenameDetails(fullFilename: string) {
-  if (fullFilename.includes('.')) {
+  const lower = fullFilename.toLowerCase()
+  if (
+    lower.endsWith(APP_JSON_EXT) &&
+    fullFilename.length > APP_JSON_EXT.length
+  ) {
     return {
-      filename: fullFilename.split('.').slice(0, -1).join('.'),
-      suffix: fullFilename.split('.').pop() ?? null
+      filename: fullFilename.slice(0, -APP_JSON_EXT.length),
+      suffix: APP_JSON_SUFFIX
     }
-  } else {
-    return { filename: fullFilename, suffix: null }
+  }
+  const dotIndex = fullFilename.lastIndexOf('.')
+  if (dotIndex <= 0) return { filename: fullFilename, suffix: null }
+  return {
+    filename: fullFilename.slice(0, dotIndex),
+    suffix: fullFilename.slice(dotIndex + 1)
   }
 }
 
diff --git a/src/components/breadcrumb/SubgraphBreadcrumbItem.vue b/src/components/breadcrumb/SubgraphBreadcrumbItem.vue
index 2e22c1424e..d7b88b4a08 100644
--- a/src/components/breadcrumb/SubgraphBreadcrumbItem.vue
+++ b/src/components/breadcrumb/SubgraphBreadcrumbItem.vue
@@ -60,6 +60,7 @@ import { computed, nextTick, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 
 import { useWorkflowActionsMenu } from '@/composables/useWorkflowActionsMenu'
+import { ensureWorkflowSuffix, getWorkflowSuffix } from '@/utils/formatUtil'
 import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
 import {
   ComfyWorkflow,
@@ -70,7 +71,6 @@ import { useDialogService } from '@/services/dialogService'
 import { useCommandStore } from '@/stores/commandStore'
 import { useNodeDefStore } from '@/stores/nodeDefStore'
 import { useSubgraphNavigationStore } from '@/stores/subgraphNavigationStore'
-import { appendJsonExt } from '@/utils/formatUtil'
 import { graphHasMissingNodes } from '@/workbench/extensions/manager/utils/graphHasMissingNodes'
 
 interface Props {
@@ -107,9 +107,10 @@ const rename = async (
       workflowStore.activeSubgraph.name = newName
     } else if (workflowStore.activeWorkflow) {
       try {
+        const suffix = getWorkflowSuffix(workflowStore.activeWorkflow.suffix)
         await workflowService.renameWorkflow(
           workflowStore.activeWorkflow,
-          ComfyWorkflow.basePath + appendJsonExt(newName)
+          ComfyWorkflow.basePath + ensureWorkflowSuffix(newName, suffix)
         )
       } catch (error) {
         console.error(error)
diff --git a/src/components/builder/BuilderMenu.vue b/src/components/builder/BuilderMenu.vue
index cd9e606f6f..7d33cc7a10 100644
--- a/src/components/builder/BuilderMenu.vue
+++ b/src/components/builder/BuilderMenu.vue
@@ -51,19 +51,28 @@ import { storeToRefs } from 'pinia'
 import { useI18n } from 'vue-i18n'
 
 import Popover from '@/components/ui/Popover.vue'
+import { useErrorHandling } from '@/composables/useErrorHandling'
+import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
+import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
 import { useAppModeStore } from '@/stores/appModeStore'
 import { cn } from '@/utils/tailwindUtil'
 
-import { useBuilderSave } from './useBuilderSave'
-
 const { t } = useI18n()
 const appModeStore = useAppModeStore()
 const { hasOutputs } = storeToRefs(appModeStore)
-const { setSaving } = useBuilderSave()
+const workflowService = useWorkflowService()
+const workflowStore = useWorkflowStore()
+const { toastErrorHandler } = useErrorHandling()
 
-function onSave(close: () => void) {
-  setSaving(true)
-  close()
+async function onSave(close: () => void) {
+  const workflow = workflowStore.activeWorkflow
+  if (!workflow) return
+  try {
+    await workflowService.saveWorkflow(workflow)
+    close()
+  } catch (error) {
+    toastErrorHandler(error)
+  }
 }
 
 function onExitBuilder(close: () => void) {
diff --git a/src/components/builder/BuilderSaveSuccessDialogContent.vue b/src/components/builder/BuilderSaveSuccessDialogContent.vue
deleted file mode 100644
index 81975a9ba3..0000000000
--- a/src/components/builder/BuilderSaveSuccessDialogContent.vue
+++ /dev/null
@@ -1,51 +0,0 @@
-<template>
-  <BuilderDialog @close="onClose">
-    <template #header-icon>
-      <i class="icon-[lucide--circle-check-big] size-4 text-green-500" />
-    </template>
-    <template #title>
-      {{ $t('builderToolbar.saveSuccess') }}
-    </template>
-
-    <p v-if="savedAsApp" class="m-0 text-sm text-muted-foreground">
-      {{ $t('builderToolbar.saveSuccessAppMessage', { name: workflowName }) }}
-    </p>
-    <p v-if="savedAsApp" class="m-0 text-sm text-muted-foreground">
-      {{ $t('builderToolbar.saveSuccessAppPrompt') }}
-    </p>
-    <p v-else class="m-0 text-sm text-muted-foreground">
-      {{ $t('builderToolbar.saveSuccessGraphMessage', { name: workflowName }) }}
-    </p>
-
-    <template #footer>
-      <Button
-        :variant="savedAsApp ? 'muted-textonly' : 'secondary'"
-        size="lg"
-        @click="onClose"
-      >
-        {{ $t('g.close') }}
-      </Button>
-      <Button
-        v-if="savedAsApp && onViewApp"
-        variant="primary"
-        size="lg"
-        @click="onViewApp"
-      >
-        {{ $t('builderToolbar.viewApp') }}
-      </Button>
-    </template>
-  </BuilderDialog>
-</template>
-
-<script setup lang="ts">
-import Button from '@/components/ui/button/Button.vue'
-
-import BuilderDialog from './BuilderDialog.vue'
-
-defineProps<{
-  workflowName: string
-  savedAsApp: boolean
-  onViewApp?: () => void
-  onClose: () => void
-}>()
-</script>
diff --git a/src/components/builder/BuilderToolbar.vue b/src/components/builder/BuilderToolbar.vue
index 48a6c16e66..b94efeccef 100644
--- a/src/components/builder/BuilderToolbar.vue
+++ b/src/components/builder/BuilderToolbar.vue
@@ -29,15 +29,19 @@
         <div class="mx-1 h-px w-4 bg-border-default" role="separator" />
       </template>
 
-      <!-- Save -->
+      <!-- Default view -->
       <ConnectOutputPopover
         v-if="!hasOutputs"
         :is-select-active="activeStep === 'builder:select'"
         @switch="setMode('builder:select')"
       >
         <button :class="cn(stepClasses, 'opacity-30 bg-transparent')">
-          <StepBadge :step="saveStep" :index="2" :model-value="activeStep" />
-          <StepLabel :step="saveStep" />
+          <StepBadge
+            :step="defaultViewStep"
+            :index="2"
+            :model-value="activeStep"
+          />
+          <StepLabel :step="defaultViewStep" />
         </button>
       </ConnectOutputPopover>
       <button
@@ -45,21 +49,26 @@
         :class="
           cn(
             stepClasses,
-            activeStep === 'save'
+            activeStep === 'setDefaultView'
               ? 'bg-interface-builder-mode-background'
               : 'hover:bg-secondary-background bg-transparent'
           )
         "
-        @click="setSaving(true)"
+        @click="showDialog()"
       >
-        <StepBadge :step="saveStep" :index="2" :model-value="activeStep" />
-        <StepLabel :step="saveStep" />
+        <StepBadge
+          :step="defaultViewStep"
+          :index="2"
+          :model-value="activeStep"
+        />
+        <StepLabel :step="defaultViewStep" />
       </button>
     </div>
   </nav>
 </template>
 
 <script setup lang="ts">
+import { storeToRefs } from 'pinia'
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 
@@ -68,19 +77,20 @@ import type { AppMode } from '@/composables/useAppMode'
 import { useAppModeStore } from '@/stores/appModeStore'
 import { cn } from '@/utils/tailwindUtil'
 
-import { useBuilderSave } from './useBuilderSave'
 import ConnectOutputPopover from './ConnectOutputPopover.vue'
 import StepBadge from './StepBadge.vue'
 import StepLabel from './StepLabel.vue'
 import type { BuilderToolbarStep } from './types'
-import { storeToRefs } from 'pinia'
+import { useAppSetDefaultView } from './useAppSetDefaultView'
 
 const { t } = useI18n()
 const { mode, setMode } = useAppMode()
 const { hasOutputs } = storeToRefs(useAppModeStore())
-const { saving, setSaving } = useBuilderSave()
+const { settingView, showDialog } = useAppSetDefaultView()
 
-const activeStep = computed(() => (saving.value ? 'save' : mode.value))
+const activeStep = computed(() =>
+  settingView.value ? 'setDefaultView' : mode.value
+)
 
 const stepClasses =
   'inline-flex h-14 min-h-8 cursor-pointer items-center gap-3 rounded-lg py-2 pr-4 pl-2 transition-colors border-none'
@@ -99,10 +109,10 @@ const arrangeStep: BuilderToolbarStep<AppMode> = {
   icon: 'icon-[lucide--layout-panel-left]'
 }
 
-const saveStep: BuilderToolbarStep<'save'> = {
-  id: 'save',
-  title: t('builderToolbar.save'),
-  subtitle: t('builderToolbar.saveDescription'),
-  icon: 'icon-[lucide--cloud-upload]'
+const defaultViewStep: BuilderToolbarStep<'setDefaultView'> = {
+  id: 'setDefaultView',
+  title: t('builderToolbar.defaultView'),
+  subtitle: t('builderToolbar.defaultViewDescription'),
+  icon: 'icon-[lucide--eye]'
 }
 </script>
diff --git a/src/components/builder/BuilderSaveDialogContent.vue b/src/components/builder/DefaultViewDialogContent.vue
similarity index 62%
rename from src/components/builder/BuilderSaveDialogContent.vue
rename to src/components/builder/DefaultViewDialogContent.vue
index af7fb2d730..ebbe612658 100644
--- a/src/components/builder/BuilderSaveDialogContent.vue
+++ b/src/components/builder/DefaultViewDialogContent.vue
@@ -1,32 +1,16 @@
 <template>
-  <BuilderDialog @close="onClose">
+  <BuilderDialog @close="$emit('close')">
     <template #title>
-      {{ $t('builderToolbar.saveAs') }}
+      {{ $t('builderToolbar.defaultViewTitle') }}
     </template>
 
-    <!-- Filename -->
-    <div class="flex flex-col gap-2">
-      <label :for="inputId" class="text-sm text-muted-foreground">
-        {{ $t('builderToolbar.filename') }}
-      </label>
-      <input
-        :id="inputId"
-        v-model="filename"
-        autofocus
-        type="text"
-        class="flex h-10 min-h-8 items-center self-stretch rounded-lg border-none bg-secondary-background pl-4 text-sm text-base-foreground focus:outline-none"
-        @keydown.enter="filename.trim() && onSave(filename.trim(), openAsApp)"
-      />
-    </div>
-
-    <!-- Save as type -->
     <div class="flex flex-col gap-2">
       <label class="text-sm text-muted-foreground">
-        {{ $t('builderToolbar.saveAsLabel') }}
+        {{ $t('builderToolbar.defaultViewLabel') }}
       </label>
       <div role="radiogroup" class="flex flex-col gap-2">
         <Button
-          v-for="option in saveTypeOptions"
+          v-for="option in viewTypeOptions"
           :key="option.value.toString()"
           role="radio"
           :aria-checked="openAsApp === option.value"
@@ -61,23 +45,18 @@
     </div>
 
     <template #footer>
-      <Button variant="muted-textonly" size="lg" @click="onClose">
+      <Button variant="muted-textonly" size="lg" @click="$emit('close')">
         {{ $t('g.cancel') }}
       </Button>
-      <Button
-        variant="secondary"
-        size="lg"
-        :disabled="!filename.trim()"
-        @click="onSave(filename.trim(), openAsApp)"
-      >
-        {{ $t('g.save') }}
+      <Button variant="secondary" size="lg" @click="$emit('apply', openAsApp)">
+        {{ $t('g.apply') }}
       </Button>
     </template>
   </BuilderDialog>
 </template>
 
 <script setup lang="ts">
-import { ref, useId } from 'vue'
+import { ref } from 'vue'
 import { useI18n } from 'vue-i18n'
 
 import Button from '@/components/ui/button/Button.vue'
@@ -87,17 +66,18 @@ import BuilderDialog from './BuilderDialog.vue'
 
 const { t } = useI18n()
 
-const { defaultFilename, onSave, onClose } = defineProps<{
-  defaultFilename: string
-  onSave: (filename: string, openAsApp: boolean) => void
-  onClose: () => void
+const { initialOpenAsApp = true } = defineProps<{
+  initialOpenAsApp?: boolean
 }>()
 
-const inputId = useId()
-const filename = ref(defaultFilename)
-const openAsApp = ref(true)
+defineEmits<{
+  apply: [openAsApp: boolean]
+  close: []
+}>()
 
-const saveTypeOptions = [
+const openAsApp = ref(initialOpenAsApp)
+
+const viewTypeOptions = [
   {
     value: true,
     icon: 'icon-[lucide--app-window]',
diff --git a/src/components/builder/useAppSetDefaultView.test.ts b/src/components/builder/useAppSetDefaultView.test.ts
new file mode 100644
index 0000000000..2080c3935a
--- /dev/null
+++ b/src/components/builder/useAppSetDefaultView.test.ts
@@ -0,0 +1,146 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const mockDialogService = vi.hoisted(() => ({
+  showLayoutDialog: vi.fn()
+}))
+
+const mockDialogStore = vi.hoisted(() => ({
+  closeDialog: vi.fn(),
+  isDialogOpen: vi.fn<(key: string) => boolean>().mockReturnValue(false)
+}))
+
+const mockWorkflowStore = vi.hoisted(() => ({
+  activeWorkflow: null as { initialMode?: string | null } | null
+}))
+
+const mockApp = vi.hoisted(() => ({
+  rootGraph: { extra: {} as Record<string, unknown> }
+}))
+
+vi.mock('@/services/dialogService', () => ({
+  useDialogService: () => mockDialogService
+}))
+
+vi.mock('@/stores/dialogStore', () => ({
+  useDialogStore: () => mockDialogStore
+}))
+
+vi.mock('@/platform/workflow/management/stores/workflowStore', () => ({
+  useWorkflowStore: () => mockWorkflowStore
+}))
+
+vi.mock('@/scripts/app', () => ({
+  app: mockApp
+}))
+
+vi.mock('./DefaultViewDialogContent.vue', () => ({
+  default: { name: 'MockDefaultViewDialogContent' }
+}))
+
+import { useAppSetDefaultView } from './useAppSetDefaultView'
+
+describe('useAppSetDefaultView', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockWorkflowStore.activeWorkflow = null
+    mockApp.rootGraph.extra = {}
+  })
+
+  describe('settingView', () => {
+    it('reflects dialogStore.isDialogOpen', () => {
+      mockDialogStore.isDialogOpen.mockReturnValue(true)
+      const { settingView } = useAppSetDefaultView()
+      expect(settingView.value).toBe(true)
+    })
+  })
+
+  describe('showDialog', () => {
+    it('opens dialog via dialogService', () => {
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      expect(mockDialogService.showLayoutDialog).toHaveBeenCalledOnce()
+    })
+
+    it('passes initialOpenAsApp true when initialMode is not graph', () => {
+      mockWorkflowStore.activeWorkflow = { initialMode: 'app' }
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      expect(call.props.initialOpenAsApp).toBe(true)
+    })
+
+    it('passes initialOpenAsApp false when initialMode is graph', () => {
+      mockWorkflowStore.activeWorkflow = { initialMode: 'graph' }
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      expect(call.props.initialOpenAsApp).toBe(false)
+    })
+
+    it('passes initialOpenAsApp true when no active workflow', () => {
+      mockWorkflowStore.activeWorkflow = null
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      expect(call.props.initialOpenAsApp).toBe(true)
+    })
+  })
+
+  describe('handleApply', () => {
+    it('sets initialMode to app when openAsApp is true', () => {
+      const workflow = { initialMode: null as string | null }
+      mockWorkflowStore.activeWorkflow = workflow
+
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      call.props.onApply(true)
+
+      expect(workflow.initialMode).toBe('app')
+    })
+
+    it('sets initialMode to graph when openAsApp is false', () => {
+      const workflow = { initialMode: null as string | null }
+      mockWorkflowStore.activeWorkflow = workflow
+
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      call.props.onApply(false)
+
+      expect(workflow.initialMode).toBe('graph')
+    })
+
+    it('sets linearMode on rootGraph.extra', () => {
+      mockWorkflowStore.activeWorkflow = { initialMode: null }
+
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      call.props.onApply(true)
+
+      expect(mockApp.rootGraph.extra.linearMode).toBe(true)
+    })
+
+    it('closes dialog after applying', () => {
+      mockWorkflowStore.activeWorkflow = { initialMode: null }
+
+      const { showDialog } = useAppSetDefaultView()
+      showDialog()
+
+      const call = mockDialogService.showLayoutDialog.mock.calls[0][0]
+      call.props.onApply(true)
+
+      expect(mockDialogStore.closeDialog).toHaveBeenCalledWith({
+        key: 'builder-default-view'
+      })
+    })
+  })
+})
diff --git a/src/components/builder/useAppSetDefaultView.ts b/src/components/builder/useAppSetDefaultView.ts
new file mode 100644
index 0000000000..f83537bee3
--- /dev/null
+++ b/src/components/builder/useAppSetDefaultView.ts
@@ -0,0 +1,47 @@
+import { computed } from 'vue'
+
+import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
+import { app } from '@/scripts/app'
+import { useDialogService } from '@/services/dialogService'
+import { useDialogStore } from '@/stores/dialogStore'
+
+import DefaultViewDialogContent from './DefaultViewDialogContent.vue'
+
+const DIALOG_KEY = 'builder-default-view'
+
+export function useAppSetDefaultView() {
+  const workflowStore = useWorkflowStore()
+  const dialogService = useDialogService()
+  const dialogStore = useDialogStore()
+
+  const settingView = computed(() => dialogStore.isDialogOpen(DIALOG_KEY))
+
+  function showDialog() {
+    dialogService.showLayoutDialog({
+      key: DIALOG_KEY,
+      component: DefaultViewDialogContent,
+      props: {
+        initialOpenAsApp: workflowStore.activeWorkflow?.initialMode !== 'graph',
+        onApply: handleApply,
+        onClose: closeDialog
+      }
+    })
+  }
+
+  function handleApply(openAsApp: boolean) {
+    const workflow = workflowStore.activeWorkflow
+    if (!workflow) return
+
+    workflow.initialMode = openAsApp ? 'app' : 'graph'
+    const extra = (app.rootGraph.extra ??= {})
+    extra.linearMode = openAsApp
+    workflow.changeTracker?.checkState()
+    closeDialog()
+  }
+
+  function closeDialog() {
+    dialogStore.closeDialog({ key: DIALOG_KEY })
+  }
+
+  return { settingView, showDialog }
+}
diff --git a/src/components/builder/useBuilderSave.ts b/src/components/builder/useBuilderSave.ts
deleted file mode 100644
index 68df8b1331..0000000000
--- a/src/components/builder/useBuilderSave.ts
+++ /dev/null
@@ -1,134 +0,0 @@
-import { ref } from 'vue'
-
-import { useErrorHandling } from '@/composables/useErrorHandling'
-import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
-import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
-import { useDialogService } from '@/services/dialogService'
-import { useAppMode } from '@/composables/useAppMode'
-import { useAppModeStore } from '@/stores/appModeStore'
-import { useDialogStore } from '@/stores/dialogStore'
-
-import BuilderSaveDialogContent from './BuilderSaveDialogContent.vue'
-import BuilderSaveSuccessDialogContent from './BuilderSaveSuccessDialogContent.vue'
-import { whenever } from '@vueuse/core'
-
-const SAVE_DIALOG_KEY = 'builder-save'
-const SUCCESS_DIALOG_KEY = 'builder-save-success'
-
-export function useBuilderSave() {
-  const { setMode } = useAppMode()
-  const { toastErrorHandler } = useErrorHandling()
-  const workflowStore = useWorkflowStore()
-  const workflowService = useWorkflowService()
-  const dialogService = useDialogService()
-  const appModeStore = useAppModeStore()
-  const dialogStore = useDialogStore()
-
-  const saving = ref(false)
-
-  whenever(saving, onBuilderSave)
-
-  function setSaving(value: boolean) {
-    saving.value = value
-  }
-
-  async function onBuilderSave() {
-    const workflow = workflowStore.activeWorkflow
-    if (!workflow) {
-      resetSaving()
-      return
-    }
-
-    if (!workflow.isTemporary && workflow.initialMode != null) {
-      // Re-save with the previously chosen mode — no dialog needed.
-      try {
-        appModeStore.flushSelections()
-        await workflowService.saveWorkflow(workflow)
-        showSuccessDialog(workflow.filename, workflow.initialMode === 'app')
-      } catch (e) {
-        toastErrorHandler(e)
-        resetSaving()
-      }
-      return
-    }
-
-    showSaveDialog(workflow.filename)
-  }
-
-  function showSaveDialog(defaultFilename: string) {
-    dialogService.showLayoutDialog({
-      key: SAVE_DIALOG_KEY,
-      component: BuilderSaveDialogContent,
-      props: {
-        defaultFilename,
-        onSave: handleSave,
-        onClose: handleCancelSave
-      },
-      dialogComponentProps: {
-        onClose: resetSaving
-      }
-    })
-  }
-
-  function handleCancelSave() {
-    closeSaveDialog()
-    resetSaving()
-  }
-
-  async function handleSave(filename: string, openAsApp: boolean) {
-    try {
-      const workflow = workflowStore.activeWorkflow
-      if (!workflow) return
-
-      appModeStore.flushSelections()
-      const mode = openAsApp ? 'app' : 'graph'
-      const saved = await workflowService.saveWorkflowAs(workflow, {
-        filename,
-        initialMode: mode
-      })
-
-      if (!saved) return
-
-      closeSaveDialog()
-      showSuccessDialog(filename, openAsApp)
-    } catch (e) {
-      toastErrorHandler(e)
-      closeSaveDialog()
-      resetSaving()
-    }
-  }
-
-  function showSuccessDialog(workflowName: string, savedAsApp: boolean) {
-    dialogService.showLayoutDialog({
-      key: SUCCESS_DIALOG_KEY,
-      component: BuilderSaveSuccessDialogContent,
-      props: {
-        workflowName,
-        savedAsApp,
-        onViewApp: () => {
-          setMode('app')
-          closeSuccessDialog()
-        },
-        onClose: closeSuccessDialog
-      },
-      dialogComponentProps: {
-        onClose: resetSaving
-      }
-    })
-  }
-
-  function closeSaveDialog() {
-    dialogStore.closeDialog({ key: SAVE_DIALOG_KEY })
-  }
-
-  function closeSuccessDialog() {
-    dialogStore.closeDialog({ key: SUCCESS_DIALOG_KEY })
-    resetSaving()
-  }
-
-  function resetSaving() {
-    saving.value = false
-  }
-
-  return { saving, setSaving }
-}
diff --git a/src/components/sidebar/tabs/WorkflowsSidebarTab.vue b/src/components/sidebar/tabs/WorkflowsSidebarTab.vue
index 224e797a0d..2b0383a919 100644
--- a/src/components/sidebar/tabs/WorkflowsSidebarTab.vue
+++ b/src/components/sidebar/tabs/WorkflowsSidebarTab.vue
@@ -161,7 +161,7 @@ import {
 } from '@/platform/workflow/management/stores/workflowStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
 import type { TreeExplorerNode, TreeNode } from '@/types/treeExplorerTypes'
-import { appendJsonExt } from '@/utils/formatUtil'
+import { ensureWorkflowSuffix, getWorkflowSuffix } from '@/utils/formatUtil'
 import { buildTree, sortedTree } from '@/utils/treeUtil'
 
 const settingStore = useSettingStore()
@@ -256,10 +256,11 @@ const renderTreeNode = (
     ? {
         handleClick,
         async handleRename(newName: string) {
+          const suffix = getWorkflowSuffix(workflow.suffix)
           const newPath =
             type === WorkflowTreeType.Browse
-              ? workflow.directory + '/' + appendJsonExt(newName)
-              : ComfyWorkflow.basePath + appendJsonExt(newName)
+              ? workflow.directory + '/' + ensureWorkflowSuffix(newName, suffix)
+              : ComfyWorkflow.basePath + ensureWorkflowSuffix(newName, suffix)
 
           await workflowService.renameWorkflow(workflow, newPath)
         },
diff --git a/src/composables/useCoreCommands.ts b/src/composables/useCoreCommands.ts
index cbca185ba4..a3575815a6 100644
--- a/src/composables/useCoreCommands.ts
+++ b/src/composables/useCoreCommands.ts
@@ -53,6 +53,7 @@ import { useColorPaletteStore } from '@/stores/workspace/colorPaletteStore'
 import { useRightSidePanelStore } from '@/stores/workspace/rightSidePanelStore'
 import { useSearchBoxStore } from '@/stores/workspace/searchBoxStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
+import { ensureWorkflowSuffix, getWorkflowSuffix } from '@/utils/formatUtil'
 import {
   getAllNonIoNodesInSubgraph,
   getExecutionIdsForSelectedNodes
@@ -207,7 +208,9 @@ export function useCoreCommands(): ComfyCommand[] {
         })
         if (!newName || newName === workflow.filename) return
 
-        const newPath = workflow.directory + '/' + newName + '.json'
+        const suffix = getWorkflowSuffix(workflow.suffix)
+        const newPath =
+          workflow.directory + '/' + ensureWorkflowSuffix(newName, suffix)
         await workflowService.renameWorkflow(workflow, newPath)
       }
     },
diff --git a/src/locales/en/main.json b/src/locales/en/main.json
index 7385568809..5210317122 100644
--- a/src/locales/en/main.json
+++ b/src/locales/en/main.json
@@ -1075,7 +1075,9 @@
     "exportWorkflow": "Export Workflow",
     "enterFilename": "Enter the filename",
     "enterFilenamePrompt": "Enter the filename:",
-    "saveWorkflow": "Save workflow"
+    "saveWorkflow": "Save workflow",
+    "savedAsApp": "Converted to app workflow",
+    "savedAsWorkflow": "Converted to node graph only workflow"
   },
   "subgraphStore": {
     "confirmDeleteTitle": "Delete blueprint?",
@@ -3352,24 +3354,18 @@
     "selectDescription": "Choose inputs/outputs",
     "arrange": "Preview",
     "arrangeDescription": "Review app layout",
-    "save": "Save",
-    "saveDescription": "Save and finish",
+    "defaultView": "Set a default view",
+    "defaultViewDescription": "Choose how this opens",
     "connectOutput": "Connect an output",
     "connectOutputBody1": "Your app needs at least one output to be connected before it can be saved.",
     "connectOutputBody2": "Switch to the 'Select' step and click on output nodes to add them here.",
     "switchToSelect": "Switch to Select",
-    "saveAs": "Save as",
-    "filename": "Filename",
-    "saveAsLabel": "Save this workflow as a ...",
+    "defaultViewTitle": "Set the default view for this workflow",
+    "defaultViewLabel": "By default, this workflow will open as:",
     "app": "App",
     "appDescription": "Opens as an app by default",
     "nodeGraph": "Node graph",
-    "nodeGraphDescription": "Opens as node graph by default",
-    "saveSuccess": "Successfully saved",
-    "saveSuccessAppMessage": "'{name}' has been saved. It will open in App Mode by default from now on.",
-    "saveSuccessAppPrompt": "Would you like to view it now?",
-    "saveSuccessGraphMessage": "'{name}' has been saved. It will open as a node graph by default.",
-    "viewApp": "View app"
+    "nodeGraphDescription": "Opens as node graph by default"
   },
   "builderMenu": {
     "exitAppBuilder": "Exit app builder"
diff --git a/src/platform/workflow/core/services/workflowService.test.ts b/src/platform/workflow/core/services/workflowService.test.ts
index b0d6781b64..8f8c6bc5d6 100644
--- a/src/platform/workflow/core/services/workflowService.test.ts
+++ b/src/platform/workflow/core/services/workflowService.test.ts
@@ -8,6 +8,7 @@ import type {
 } from '@/platform/workflow/management/stores/comfyWorkflow'
 import { ComfyWorkflow as ComfyWorkflowClass } from '@/platform/workflow/management/stores/comfyWorkflow'
 import { useSettingStore } from '@/platform/settings/settingStore'
+import { useToastStore } from '@/platform/updates/common/toastStore'
 import type { ComfyWorkflow } from '@/platform/workflow/management/stores/workflowStore'
 import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
 import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
@@ -55,10 +56,13 @@ function makeWorkflowData(
   }
 }
 
-const { mockShowMissingNodes, mockShowMissingModels } = vi.hoisted(() => ({
-  mockShowMissingNodes: vi.fn(),
-  mockShowMissingModels: vi.fn()
-}))
+const { mockShowMissingNodes, mockShowMissingModels, mockConfirm } = vi.hoisted(
+  () => ({
+    mockShowMissingNodes: vi.fn(),
+    mockShowMissingModels: vi.fn(),
+    mockConfirm: vi.fn()
+  })
+)
 
 vi.mock('@/composables/useMissingNodesDialog', () => ({
   useMissingNodesDialog: () => ({ show: mockShowMissingNodes, hide: vi.fn() })
@@ -71,7 +75,7 @@ vi.mock('@/composables/useMissingModelsDialog', () => ({
 vi.mock('@/services/dialogService', () => ({
   useDialogService: () => ({
     prompt: vi.fn(),
-    confirm: vi.fn()
+    confirm: mockConfirm
   })
 }))
 
@@ -463,17 +467,6 @@ describe('useWorkflowService', () => {
         expect(appMode.mode.value).toBe('app')
       })
 
-      it('syncs linearMode to rootGraph.extra for draft persistence', async () => {
-        const workflow = createModeTestWorkflow({ loaded: false })
-
-        await service.afterLoadNewGraph(
-          workflow,
-          makeWorkflowData({ linearMode: true })
-        )
-
-        expect(app.rootGraph.extra.linearMode).toBe(true)
-      })
-
       it('reads initialMode from file when draft lacks linearMode (restoration)', async () => {
         const filePath = 'workflows/saved-app.json'
         const fileInitialState = makeWorkflowData({ linearMode: true })
@@ -507,7 +500,6 @@ describe('useWorkflowService', () => {
 
         // initialMode should come from the file, not the draft
         expect(persistedWorkflow.initialMode).toBe('app')
-        expect(app.rootGraph.extra.linearMode).toBe(true)
       })
     })
 
@@ -533,4 +525,194 @@ describe('useWorkflowService', () => {
       })
     })
   })
+
+  describe('saveWorkflowAs', () => {
+    let workflowStore: ReturnType<typeof useWorkflowStore>
+    let service: ReturnType<typeof useWorkflowService>
+
+    beforeEach(() => {
+      workflowStore = useWorkflowStore()
+      service = useWorkflowService()
+      vi.spyOn(workflowStore, 'saveWorkflow').mockResolvedValue()
+      vi.spyOn(workflowStore, 'renameWorkflow').mockResolvedValue()
+    })
+
+    function createTemporaryWorkflow(
+      directory: string = 'workflows'
+    ): LoadedComfyWorkflow {
+      const workflow = new ComfyWorkflowClass({
+        path: directory + '/temp.json',
+        modified: Date.now(),
+        size: 100
+      })
+      workflow.changeTracker = createMockChangeTracker()
+      workflow.content = '{}'
+      workflow.originalContent = '{}'
+      Object.defineProperty(workflow, 'isTemporary', { get: () => true })
+      return workflow as LoadedComfyWorkflow
+    }
+
+    it('appends .app.json extension when initialMode is app', async () => {
+      const workflow = createTemporaryWorkflow()
+      workflow.initialMode = 'app'
+
+      await service.saveWorkflowAs(workflow, { filename: 'my-workflow' })
+
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/my-workflow.app.json'
+      )
+    })
+
+    it('appends .json extension when initialMode is graph', async () => {
+      const workflow = createTemporaryWorkflow()
+      workflow.initialMode = 'graph'
+
+      await service.saveWorkflowAs(workflow, { filename: 'my-workflow' })
+
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/my-workflow.json'
+      )
+    })
+
+    it('appends .json extension when initialMode is not set', async () => {
+      const workflow = createTemporaryWorkflow()
+
+      await service.saveWorkflowAs(workflow, { filename: 'my-workflow' })
+
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/my-workflow.json'
+      )
+    })
+  })
+
+  describe('saveWorkflow', () => {
+    let workflowStore: ReturnType<typeof useWorkflowStore>
+    let toastStore: ReturnType<typeof useToastStore>
+    let service: ReturnType<typeof useWorkflowService>
+
+    beforeEach(() => {
+      workflowStore = useWorkflowStore()
+      toastStore = useToastStore()
+      service = useWorkflowService()
+      vi.spyOn(workflowStore, 'saveWorkflow').mockResolvedValue()
+      vi.spyOn(workflowStore, 'renameWorkflow').mockResolvedValue()
+    })
+
+    function createSaveableWorkflow(path: string): LoadedComfyWorkflow {
+      const workflow = new ComfyWorkflowClass({
+        path,
+        modified: Date.now(),
+        size: 100
+      })
+      workflow.changeTracker = createMockChangeTracker()
+      workflow.content = '{}'
+      workflow.originalContent = '{}'
+      return workflow as LoadedComfyWorkflow
+    }
+
+    it('renames .json to .app.json when initialMode is app', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.json')
+      workflow.initialMode = 'app'
+
+      await service.saveWorkflow(workflow)
+
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/test.app.json'
+      )
+      expect(workflowStore.saveWorkflow).toHaveBeenCalledWith(workflow)
+    })
+
+    it('renames .app.json to .json when initialMode is graph', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.app.json')
+      workflow.initialMode = 'graph'
+
+      await service.saveWorkflow(workflow)
+
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/test.json'
+      )
+      expect(workflowStore.saveWorkflow).toHaveBeenCalledWith(workflow)
+    })
+
+    it('does not rename when extension already matches', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.app.json')
+      workflow.initialMode = 'app'
+
+      await service.saveWorkflow(workflow)
+
+      expect(workflowStore.renameWorkflow).not.toHaveBeenCalled()
+      expect(workflowStore.saveWorkflow).toHaveBeenCalledWith(workflow)
+    })
+
+    it('shows toast only when rename occurs', async () => {
+      const addSpy = vi.spyOn(toastStore, 'add')
+
+      const workflow = createSaveableWorkflow('workflows/test.json')
+      workflow.initialMode = 'app'
+
+      await service.saveWorkflow(workflow)
+
+      expect(addSpy).toHaveBeenCalledWith(
+        expect.objectContaining({ severity: 'info' })
+      )
+    })
+
+    it('does not show toast when no rename occurs', async () => {
+      const addSpy = vi.spyOn(toastStore, 'add')
+
+      const workflow = createSaveableWorkflow('workflows/test.app.json')
+      workflow.initialMode = 'app'
+
+      await service.saveWorkflow(workflow)
+
+      expect(addSpy).not.toHaveBeenCalled()
+    })
+
+    it('does not rename when initialMode is not set', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.json')
+
+      await service.saveWorkflow(workflow)
+
+      expect(workflowStore.renameWorkflow).not.toHaveBeenCalled()
+    })
+
+    it('prompts for overwrite when target path already exists', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.json')
+      workflow.initialMode = 'app'
+
+      const existing = createSaveableWorkflow('workflows/test.app.json')
+      vi.spyOn(workflowStore, 'getWorkflowByPath').mockReturnValue(existing)
+      vi.spyOn(workflowStore, 'deleteWorkflow').mockResolvedValue()
+      mockConfirm.mockResolvedValue(true)
+
+      await service.saveWorkflow(workflow)
+
+      expect(mockConfirm).toHaveBeenCalled()
+      expect(workflowStore.renameWorkflow).toHaveBeenCalledWith(
+        workflow,
+        'workflows/test.app.json'
+      )
+      expect(workflowStore.saveWorkflow).toHaveBeenCalledWith(workflow)
+    })
+
+    it('saves without renaming when user declines overwrite', async () => {
+      const workflow = createSaveableWorkflow('workflows/test.json')
+      workflow.initialMode = 'app'
+
+      const existing = createSaveableWorkflow('workflows/test.app.json')
+      vi.spyOn(workflowStore, 'getWorkflowByPath').mockReturnValue(existing)
+      mockConfirm.mockResolvedValue(false)
+
+      await service.saveWorkflow(workflow)
+
+      expect(mockConfirm).toHaveBeenCalled()
+      expect(workflowStore.renameWorkflow).not.toHaveBeenCalled()
+      expect(workflowStore.saveWorkflow).toHaveBeenCalledWith(workflow)
+    })
+  })
 })
diff --git a/src/platform/workflow/core/services/workflowService.ts b/src/platform/workflow/core/services/workflowService.ts
index 3c50de2657..53047c19b3 100644
--- a/src/platform/workflow/core/services/workflowService.ts
+++ b/src/platform/workflow/core/services/workflowService.ts
@@ -7,7 +7,6 @@ import type { Point, SerialisableGraph } from '@/lib/litegraph/src/litegraph'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { useToastStore } from '@/platform/updates/common/toastStore'
 import { useWorkflowDraftStore } from '@/platform/workflow/persistence/stores/workflowDraftStore'
-import { syncLinearMode } from '@/platform/workflow/management/stores/comfyWorkflow'
 import {
   ComfyWorkflow,
   useWorkflowStore
@@ -25,7 +24,7 @@ import type { AppMode } from '@/composables/useAppMode'
 import { useDomWidgetStore } from '@/stores/domWidgetStore'
 import { useExecutionErrorStore } from '@/stores/executionErrorStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
-import { appendJsonExt } from '@/utils/formatUtil'
+import { appendJsonExt, appendWorkflowJsonExt } from '@/utils/formatUtil'
 
 function linearModeToAppMode(linearMode: unknown): AppMode | null {
   if (typeof linearMode !== 'boolean') return null
@@ -44,6 +43,15 @@ export const useWorkflowService = () => {
   const executionErrorStore = useExecutionErrorStore()
   const workflowDraftStore = useWorkflowDraftStore()
 
+  function confirmOverwrite(targetPath: string) {
+    return dialogService.confirm({
+      title: t('sideToolbar.workflowTab.confirmOverwriteTitle'),
+      type: 'overwrite',
+      message: t('sideToolbar.workflowTab.confirmOverwrite'),
+      itemList: [targetPath]
+    })
+  }
+
   async function getFilename(defaultName: string): Promise<string | null> {
     if (settingStore.get('Comfy.PromptFilename')) {
       let filename = await dialogService.prompt({
@@ -103,26 +111,21 @@ export const useWorkflowService = () => {
    */
   const saveWorkflowAs = async (
     workflow: ComfyWorkflow,
-    options: { filename?: string; initialMode?: AppMode } = {}
+    options: { filename?: string } = {}
   ): Promise<boolean> => {
     const newFilename = options.filename ?? (await workflow.promptSave())
     if (!newFilename) return false
 
-    const newPath = workflow.directory + '/' + appendJsonExt(newFilename)
+    const isApp = workflow.initialMode === 'app'
+    const newPath =
+      workflow.directory + '/' + appendWorkflowJsonExt(newFilename, isApp)
     const existingWorkflow = workflowStore.getWorkflowByPath(newPath)
 
     const isSelfOverwrite =
       existingWorkflow?.path === workflow.path && !existingWorkflow?.isTemporary
 
     if (existingWorkflow && !existingWorkflow.isTemporary) {
-      const res = await dialogService.confirm({
-        title: t('sideToolbar.workflowTab.confirmOverwriteTitle'),
-        type: 'overwrite',
-        message: t('sideToolbar.workflowTab.confirmOverwrite'),
-        itemList: [newPath]
-      })
-
-      if (res !== true) return false
+      if ((await confirmOverwrite(newPath)) !== true) return false
 
       if (!isSelfOverwrite) {
         const deleted = await deleteWorkflow(existingWorkflow, true)
@@ -130,9 +133,6 @@ export const useWorkflowService = () => {
       }
     }
 
-    if (options.initialMode) workflow.initialMode = options.initialMode
-
-    syncLinearMode(workflow, [app.rootGraph], { flushLinearData: true })
     workflow.changeTracker?.checkState()
 
     if (isSelfOverwrite) {
@@ -156,8 +156,34 @@ export const useWorkflowService = () => {
     if (workflow.isTemporary) {
       await saveWorkflowAs(workflow)
     } else {
-      syncLinearMode(workflow, [app.rootGraph], { flushLinearData: true })
       workflow.changeTracker?.checkState()
+
+      const isApp = workflow.initialMode === 'app'
+      const expectedPath =
+        workflow.directory +
+        '/' +
+        appendWorkflowJsonExt(workflow.filename, isApp)
+      if (workflow.path !== expectedPath) {
+        const existing = workflowStore.getWorkflowByPath(expectedPath)
+        if (existing && !existing.isTemporary) {
+          if ((await confirmOverwrite(expectedPath)) !== true) {
+            await workflowStore.saveWorkflow(workflow)
+            return
+          }
+          await deleteWorkflow(existing, true)
+        }
+        await renameWorkflow(workflow, expectedPath)
+        toastStore.add({
+          severity: 'info',
+          summary: t(
+            isApp
+              ? 'workflowService.savedAsApp'
+              : 'workflowService.savedAsWorkflow'
+          ),
+          life: 3000
+        })
+      }
+
       await workflowStore.saveWorkflow(workflow)
     }
   }
@@ -404,7 +430,6 @@ export const useWorkflowService = () => {
               ) ?? freshLoadMode
             trackIfEnteringApp(loadedWorkflow)
           }
-          syncLinearMode(loadedWorkflow, [workflowData, app.rootGraph])
           loadedWorkflow.changeTracker.reset(workflowData)
           loadedWorkflow.changeTracker.restore()
           return
@@ -417,7 +442,6 @@ export const useWorkflowService = () => {
       )
       tempWorkflow.initialMode = freshLoadMode
       trackIfEnteringApp(tempWorkflow)
-      syncLinearMode(tempWorkflow, [workflowData, app.rootGraph])
       await workflowStore.openWorkflow(tempWorkflow)
       return
     }
@@ -427,7 +451,6 @@ export const useWorkflowService = () => {
       loadedWorkflow.initialMode = freshLoadMode
       trackIfEnteringApp(loadedWorkflow)
     }
-    syncLinearMode(loadedWorkflow, [workflowData, app.rootGraph])
     loadedWorkflow.changeTracker.reset(workflowData)
     loadedWorkflow.changeTracker.restore()
   }
diff --git a/src/platform/workflow/management/stores/comfyWorkflow.ts b/src/platform/workflow/management/stores/comfyWorkflow.ts
index 3e395485a4..ff535859cc 100644
--- a/src/platform/workflow/management/stores/comfyWorkflow.ts
+++ b/src/platform/workflow/management/stores/comfyWorkflow.ts
@@ -24,31 +24,6 @@ export interface PendingWarnings {
   }
 }
 
-type LinearModeTarget = { extra?: Record<string, unknown> | null } | null
-
-export function syncLinearMode(
-  workflow: ComfyWorkflow,
-  targets: LinearModeTarget[],
-  options?: { flushLinearData?: boolean }
-): void {
-  for (const target of targets) {
-    if (!target) continue
-    if (workflow.initialMode === 'app' || workflow.initialMode === 'graph') {
-      const extra = (target.extra ??= {})
-      extra.linearMode = workflow.initialMode === 'app'
-    } else {
-      delete target.extra?.linearMode
-    }
-    if (options?.flushLinearData && workflow.dirtyLinearData) {
-      const extra = (target.extra ??= {})
-      extra.linearData = workflow.dirtyLinearData
-    }
-  }
-  if (options?.flushLinearData && workflow.dirtyLinearData) {
-    workflow.dirtyLinearData = null
-  }
-}
-
 export class ComfyWorkflow extends UserFile {
   static readonly basePath: string = 'workflows/'
   readonly tintCanvasBg?: string
@@ -77,12 +52,6 @@ export class ComfyWorkflow extends UserFile {
    * Takes precedence over initialMode when present.
    */
   activeMode: AppMode | null = null
-  /**
-   * In-progress builder selections not yet persisted via save.
-   * Preserved across tab switches, discarded on exitBuilder.
-   */
-  dirtyLinearData: LinearData | null = null
-
   /**
    * @param options The path, modified, and size of the workflow.
    * Note: path is the full path, including the 'workflows/' prefix.
diff --git a/src/stores/appModeStore.test.ts b/src/stores/appModeStore.test.ts
index d0a02c16e8..924c843210 100644
--- a/src/stores/appModeStore.test.ts
+++ b/src/stores/appModeStore.test.ts
@@ -1,32 +1,18 @@
-import { createPinia, setActivePinia } from 'pinia'
+import { createTestingPinia } from '@pinia/testing'
+import { setActivePinia } from 'pinia'
+import { nextTick } from 'vue'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
-import { computed, ref } from 'vue'
 
-import type { AppMode } from '@/composables/useAppMode'
+import type { LoadedComfyWorkflow } from '@/platform/workflow/management/stores/comfyWorkflow'
+import { ComfyWorkflow as ComfyWorkflowClass } from '@/platform/workflow/management/stores/comfyWorkflow'
+import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
+import { app } from '@/scripts/app'
+import { createMockChangeTracker } from '@/utils/__tests__/litegraphTestUtils'
 
-import { useAppModeStore } from '@/stores/appModeStore'
-
-const modeRef = ref<AppMode>('graph')
-const mockSetMode = vi.fn()
-
-vi.mock('@/composables/useAppMode', () => ({
-  useAppMode: () => ({
-    mode: computed(() => modeRef.value),
-    setMode: mockSetMode,
-    isBuilderMode: computed(
-      () =>
-        modeRef.value === 'builder:select' ||
-        modeRef.value === 'builder:arrange'
-    ),
-    isAppMode: computed(
-      () => modeRef.value === 'app' || modeRef.value === 'builder:arrange'
-    ),
-    isSelectMode: computed(() => modeRef.value === 'builder:select'),
-    isArrangeMode: computed(() => modeRef.value === 'builder:arrange'),
-    isGraphMode: computed(
-      () => modeRef.value === 'graph' || modeRef.value === 'builder:select'
-    )
-  })
+vi.mock('@/scripts/app', () => ({
+  app: {
+    rootGraph: { extra: {} }
+  }
 }))
 
 vi.mock('@/renderer/core/canvas/canvasStore', () => ({
@@ -35,56 +21,143 @@ vi.mock('@/renderer/core/canvas/canvasStore', () => ({
   })
 }))
 
-vi.mock('@/platform/workflow/management/stores/workflowStore', () => ({
-  useWorkflowStore: () => ({
-    activeWorkflow: null
+import { useAppModeStore } from './appModeStore'
+
+function createBuilderWorkflow(
+  activeMode: string = 'builder:select'
+): LoadedComfyWorkflow {
+  const workflow = new ComfyWorkflowClass({
+    path: 'workflows/test.json',
+    modified: Date.now(),
+    size: 100
   })
-}))
+  workflow.changeTracker = createMockChangeTracker()
+  workflow.content = '{}'
+  workflow.originalContent = '{}'
+  workflow.activeMode = activeMode as LoadedComfyWorkflow['activeMode']
+  return workflow as LoadedComfyWorkflow
+}
 
 describe('appModeStore', () => {
   beforeEach(() => {
-    setActivePinia(createPinia())
-    modeRef.value = 'graph'
-    mockSetMode.mockClear()
+    setActivePinia(createTestingPinia({ stubActions: false }))
+    vi.clearAllMocks()
+    vi.mocked(app.rootGraph).extra = {}
   })
 
   describe('enterBuilder', () => {
     it('navigates to builder:arrange when in app mode with outputs', () => {
-      modeRef.value = 'app'
+      const workflowStore = useWorkflowStore()
+      workflowStore.activeWorkflow = createBuilderWorkflow('app')
+
       const store = useAppModeStore()
-      store.selectedOutputs.push('1')
+      store.selectedOutputs.push(1)
 
       store.enterBuilder()
 
-      expect(mockSetMode).toHaveBeenCalledWith('builder:arrange')
+      expect(workflowStore.activeWorkflow!.activeMode).toBe('builder:arrange')
     })
 
     it('navigates to builder:select when in app mode without outputs', () => {
-      modeRef.value = 'app'
+      const workflowStore = useWorkflowStore()
+      workflowStore.activeWorkflow = createBuilderWorkflow('app')
+
       const store = useAppModeStore()
 
       store.enterBuilder()
 
-      expect(mockSetMode).toHaveBeenCalledWith('builder:select')
+      expect(workflowStore.activeWorkflow!.activeMode).toBe('builder:select')
     })
 
     it('navigates to builder:select when in graph mode with outputs', () => {
-      modeRef.value = 'graph'
+      const workflowStore = useWorkflowStore()
+      workflowStore.activeWorkflow = createBuilderWorkflow('graph')
+
       const store = useAppModeStore()
-      store.selectedOutputs.push('1')
+      store.selectedOutputs.push(1)
 
       store.enterBuilder()
 
-      expect(mockSetMode).toHaveBeenCalledWith('builder:select')
+      expect(workflowStore.activeWorkflow!.activeMode).toBe('builder:select')
     })
 
     it('navigates to builder:select when in graph mode without outputs', () => {
-      modeRef.value = 'graph'
+      const workflowStore = useWorkflowStore()
+      workflowStore.activeWorkflow = createBuilderWorkflow('graph')
+
       const store = useAppModeStore()
 
       store.enterBuilder()
 
-      expect(mockSetMode).toHaveBeenCalledWith('builder:select')
+      expect(workflowStore.activeWorkflow!.activeMode).toBe('builder:select')
+    })
+  })
+
+  describe('linearData sync watcher', () => {
+    it('writes linearData to rootGraph.extra when in builder mode', async () => {
+      const workflowStore = useWorkflowStore()
+      const store = useAppModeStore()
+
+      workflowStore.activeWorkflow = createBuilderWorkflow()
+      await nextTick()
+
+      store.selectedOutputs.push(1)
+      await nextTick()
+
+      expect(app.rootGraph.extra.linearData).toEqual({
+        inputs: [],
+        outputs: [1]
+      })
+    })
+
+    it('does not write linearData when not in builder mode', async () => {
+      const workflowStore = useWorkflowStore()
+      const store = useAppModeStore()
+
+      const workflow = createBuilderWorkflow()
+      workflow.activeMode = 'graph'
+      workflowStore.activeWorkflow = workflow
+      await nextTick()
+
+      store.selectedOutputs.push(1)
+      await nextTick()
+
+      expect(app.rootGraph.extra.linearData).toBeUndefined()
+    })
+
+    it('does not write when rootGraph is null', async () => {
+      const workflowStore = useWorkflowStore()
+      const store = useAppModeStore()
+
+      workflowStore.activeWorkflow = createBuilderWorkflow()
+      await nextTick()
+
+      const originalRootGraph = app.rootGraph
+      Object.defineProperty(app, 'rootGraph', { value: null, writable: true })
+
+      store.selectedOutputs.push(1)
+      await nextTick()
+
+      Object.defineProperty(app, 'rootGraph', {
+        value: originalRootGraph,
+        writable: true
+      })
+    })
+
+    it('reflects input changes in linearData', async () => {
+      const workflowStore = useWorkflowStore()
+      const store = useAppModeStore()
+
+      workflowStore.activeWorkflow = createBuilderWorkflow()
+      await nextTick()
+
+      store.selectedInputs.push([42, 'prompt'])
+      await nextTick()
+
+      expect(app.rootGraph.extra.linearData).toEqual({
+        inputs: [[42, 'prompt']],
+        outputs: []
+      })
     })
   })
 })
diff --git a/src/stores/appModeStore.ts b/src/stores/appModeStore.ts
index 2726722511..262859a4c6 100644
--- a/src/stores/appModeStore.ts
+++ b/src/stores/appModeStore.ts
@@ -6,6 +6,7 @@ import type { NodeId } from '@/lib/litegraph/src/LGraphNode'
 import type { LinearData } from '@/platform/workflow/management/stores/comfyWorkflow'
 import { useCanvasStore } from '@/renderer/core/canvas/canvasStore'
 import { useWorkflowStore } from '@/platform/workflow/management/stores/workflowStore'
+import { app } from '@/scripts/app'
 
 export const useAppModeStore = defineStore('appMode', () => {
   const { getCanvas } = useCanvasStore()
@@ -28,31 +29,12 @@ export const useAppModeStore = defineStore('appMode', () => {
     loadSelections(activeWorkflow.changeTracker?.activeState?.extra?.linearData)
   }
 
-  function flushSelections() {
-    const workflow = workflowStore.activeWorkflow
-    if (workflow) {
-      workflow.dirtyLinearData = {
-        inputs: [...selectedInputs],
-        outputs: [...selectedOutputs]
-      }
-    }
-  }
-
   watch(
     () => workflowStore.activeWorkflow,
-    (newWorkflow, oldWorkflow) => {
-      // Persist in-progress builder selections to the outgoing workflow
-      if (oldWorkflow && isBuilderMode.value) {
-        oldWorkflow.dirtyLinearData = {
-          inputs: [...selectedInputs],
-          outputs: [...selectedOutputs]
-        }
-      }
-      // Load from incoming workflow: dirty state first, then persisted
+    (newWorkflow) => {
       if (newWorkflow) {
         loadSelections(
-          newWorkflow.dirtyLinearData ??
-            newWorkflow.changeTracker?.activeState?.extra?.linearData
+          newWorkflow.changeTracker?.activeState?.extra?.linearData
         )
       } else {
         loadSelections(undefined)
@@ -61,6 +43,24 @@ export const useAppModeStore = defineStore('appMode', () => {
     { immediate: true }
   )
 
+  watch(
+    () =>
+      isBuilderMode.value
+        ? { inputs: selectedInputs, outputs: selectedOutputs }
+        : null,
+    (data) => {
+      if (!data) return
+      const graph = app.rootGraph
+      if (!graph) return
+      const extra = (graph.extra ??= {})
+      extra.linearData = {
+        inputs: [...data.inputs],
+        outputs: [...data.outputs]
+      }
+    },
+    { deep: true }
+  )
+
   watch(
     () => mode.value === 'builder:select',
     (inSelect) => (getCanvas().read_only = inSelect)
@@ -75,8 +75,6 @@ export const useAppModeStore = defineStore('appMode', () => {
   }
 
   async function exitBuilder() {
-    const workflow = workflowStore.activeWorkflow
-    if (workflow) workflow.dirtyLinearData = null
     resetSelectedToWorkflow()
     setMode('graph')
   }
@@ -85,7 +83,6 @@ export const useAppModeStore = defineStore('appMode', () => {
     enterBuilder,
     exitBuilder,
     hasOutputs,
-    flushSelections,
     resetSelectedToWorkflow,
     selectedInputs,
     selectedOutputs