diff --git a/ui/src/stores/developerModeSlice.ts b/ui/src/stores/developerModeSlice.ts
new file mode 100644
index 00000000..5b794b61
--- /dev/null
+++ b/ui/src/stores/developerModeSlice.ts
@@ -0,0 +1,33 @@
+import { loadDeveloperMode, saveDeveloperMode } from '../lib/developerMode'
+import type { MediaFilter } from '../types'
+
+export type DeveloperModeSlice = {
+  developerMode: boolean
+  setDeveloperMode: (enabled: boolean) => void
+}
+
+// Runtime get() is the full AppState. The setter may also write mediaFilter
+// when leaving auditdev; that field stays owned by the gallery store.
+type DeveloperModeWriteState = DeveloperModeSlice & {
+  mediaFilter?: MediaFilter
+}
+
+type SetDeveloperModeState = (
+  partial: Partial<DeveloperModeWriteState> | ((state: DeveloperModeWriteState) => Partial<DeveloperModeWriteState>),
+) => void
+
+type GetDeveloperModeState = () => DeveloperModeWriteState
+
+export function createDeveloperModeSlice(set: SetDeveloperModeState, get: GetDeveloperModeState): DeveloperModeSlice {
+  return {
+    developerMode: loadDeveloperMode(),
+    setDeveloperMode: enabled => {
+      saveDeveloperMode(enabled)
+      const { mediaFilter } = get()
+      set({
+        developerMode: enabled,
+        mediaFilter: !enabled && mediaFilter === 'auditdev' ? 'all' : mediaFilter,
+      })
+    },
+  }
+}
diff --git a/ui/src/stores/useStore.ts b/ui/src/stores/useStore.ts
index 3f5f04fc..b3391c9b 100644
--- a/ui/src/stores/useStore.ts
+++ b/ui/src/stores/useStore.ts
@@ -3,7 +3,6 @@ import type { GenerateParams, OutputFile, MediaFilter, AspectRatio, ResolutionPr
 import { DEFAULT_DIRECT_VIDEO_MASTER_PROMPT } from '../types'
 import * as api from '../api/client'
 import { type FamilyId, type ThemeMode, type ThemePrefs } from '../lib/theme'
-import { loadDeveloperMode, saveDeveloperMode } from '../lib/developerMode'
 import { splitPromptSchedule } from '../lib/promptScheduler'
 import { DEFAULT_PRODUCTION_PROFILE, productionImageModelType, resolveSupportedVideoFormat } from '../lib/productionProfile'
 import { createKeyedWriteSequencer } from '../lib/keyedWriteSequencer'
@@ -11,6 +10,7 @@ import { createActivityPublicationGate } from '../lib/activityPublication'
 import { isGenerationJobActive } from '../lib/generationJobState'
 import { mapDirectorClipImages } from '../lib/directorClipImages'
 import { llmActivityPreview } from '../lib/llmActivityPreview'
+import { createDeveloperModeSlice } from './developerModeSlice'
 import { createDirectorSlice } from './directorSlice'
 import { createSettingsSlice } from './settingsSlice'
 import { createThemeSlice } from './themeSlice'
@@ -2330,6 +2330,10 @@ export const useStore = create<AppState>((set, get) => ({
     partial => set(partial as never),
     () => get(),
   ),
+  ...createDeveloperModeSlice(
+    partial => set(partial as never),
+    () => get(),
+  ),
   // Generation mode
   generationMode: 'video',
   editSubMode: 'retake' as import('../types').EditSubMode,
@@ -3041,15 +3045,6 @@ export const useStore = create<AppState>((set, get) => ({
   toggleSidebar: () => set(s => ({ sidebarOpen: !s.sidebarOpen })),
   setSidebarOpen: (open) => set({ sidebarOpen: open }),
 
-  developerMode: loadDeveloperMode(),
-  setDeveloperMode: (enabled) => {
-    saveDeveloperMode(enabled)
-    set(s => ({
-      developerMode: enabled,
-      mediaFilter: !enabled && s.mediaFilter === 'auditdev' ? 'all' : s.mediaFilter,
-    }))
-  },
-
   // CivitAI LoRA Browser
   // Director Pipeline Dashboard
   retakeDialogOpen: false,
diff --git a/ui/tests/architectureSlices.test.mjs b/ui/tests/architectureSlices.test.mjs
index f8d488b1..82986f2d 100644
--- a/ui/tests/architectureSlices.test.mjs
+++ b/ui/tests/architectureSlices.test.mjs
@@ -119,6 +119,49 @@ test('settings slice toggles open and tab through the public facade', async () =
   assert.equal(useStore.getState().settingsOpen, false)
 })
 
+test('developer-mode slice persists the local flag through the public facade', async () => {
+  if (!globalThis.localStorage) {
+    const { JSDOM } = await import('jsdom')
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost/' })
+    Object.assign(globalThis, {
+      window: dom.window,
+      document: dom.window.document,
+      localStorage: dom.window.localStorage,
+    })
+  }
+  globalThis.localStorage.removeItem('hocuspocus-developer-mode-v1')
+
+  const { createDeveloperModeSlice } = await import('../src/stores/developerModeSlice.ts')
+  let state
+  const set = update => {
+    const partial = typeof update === 'function' ? update(state) : update
+    state = { ...state, ...partial }
+  }
+  state = createDeveloperModeSlice(set, () => state)
+  assert.equal(state.developerMode, false)
+  state.setDeveloperMode(true)
+  assert.equal(state.developerMode, true)
+  assert.equal(globalThis.localStorage.getItem('hocuspocus-developer-mode-v1'), '1')
+
+  const { useStore } = await import('../src/stores/useStore.ts')
+  useStore.getState().setDeveloperMode(true)
+  assert.equal(useStore.getState().developerMode, true)
+  assert.equal(globalThis.localStorage.getItem('hocuspocus-developer-mode-v1'), '1')
+  useStore.getState().setDeveloperMode(false)
+  assert.equal(useStore.getState().developerMode, false)
+  assert.equal(globalThis.localStorage.getItem('hocuspocus-developer-mode-v1'), null)
+
+  useStore.setState({ mediaFilter: 'auditdev', developerMode: true })
+  useStore.getState().setDeveloperMode(false)
+  assert.equal(useStore.getState().developerMode, false)
+  assert.equal(useStore.getState().mediaFilter, 'all')
+
+  useStore.setState({ mediaFilter: 'videos' })
+  useStore.getState().setDeveloperMode(true)
+  assert.equal(useStore.getState().developerMode, true)
+  assert.equal(useStore.getState().mediaFilter, 'videos')
+})
+
 test('useStore keeps Director actions available through its existing public facade', async () => {
   const { useStore } = await import('../src/stores/useStore.ts')
   useStore.setState({ directorAutoMode: true, directorSeamless: true })