diff --git a/apps/stage-tamagotchi/src/renderer/stores/chat-sync.test.ts b/apps/stage-tamagotchi/src/renderer/stores/chat-sync.test.ts
new file mode 100644
index 000000000..c4cfc1969
--- /dev/null
+++ b/apps/stage-tamagotchi/src/renderer/stores/chat-sync.test.ts
@@ -0,0 +1,214 @@
+import type { Ref } from 'vue'
+
+import { createPinia, setActivePinia } from 'pinia'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { computed, ref } from 'vue'
+
+interface MockBroadcastMessageEvent<T> {
+  data: T
+}
+
+type MockListener = (event: MockBroadcastMessageEvent<unknown>) => void
+
+class MockBroadcastChannel {
+  static channels = new Map<string, Set<MockBroadcastChannel>>()
+
+  static reset() {
+    for (const peers of MockBroadcastChannel.channels.values()) {
+      for (const peer of peers)
+        peer.listeners.clear()
+    }
+    MockBroadcastChannel.channels.clear()
+  }
+
+  readonly name: string
+  private readonly listeners = new Set<MockListener>()
+
+  constructor(name: string) {
+    this.name = name
+    if (!MockBroadcastChannel.channels.has(name))
+      MockBroadcastChannel.channels.set(name, new Set())
+    MockBroadcastChannel.channels.get(name)?.add(this)
+  }
+
+  addEventListener(_type: 'message', listener: EventListener) {
+    this.listeners.add(listener as unknown as MockListener)
+  }
+
+  removeEventListener(_type: 'message', listener: EventListener) {
+    this.listeners.delete(listener as unknown as MockListener)
+  }
+
+  postMessage(data: unknown) {
+    const peers = MockBroadcastChannel.channels.get(this.name)
+    if (!peers)
+      return
+
+    for (const peer of peers) {
+      if (peer === this)
+        continue
+
+      for (const listener of peer.listeners)
+        listener({ data })
+    }
+  }
+
+  close() {
+    const peers = MockBroadcastChannel.channels.get(this.name)
+    peers?.delete(this)
+    this.listeners.clear()
+    if (peers && peers.size === 0)
+      MockBroadcastChannel.channels.delete(this.name)
+  }
+}
+
+interface MockState {
+  activeSessionId: Ref<string>
+  sessionMessages: Ref<Record<string, Array<{ role: string, content: string }>>>
+  sessionMetas: Ref<Record<string, unknown>>
+  setSessionMessages: ReturnType<typeof vi.fn>
+  getSessionMessages: ReturnType<typeof vi.fn>
+  ingest: ReturnType<typeof vi.fn>
+}
+
+let mockState: MockState
+
+vi.mock('@proj-airi/stage-ui/stores/chat/session-store', () => ({
+  useChatSessionStore: () => ({
+    activeSessionId: mockState.activeSessionId,
+    sessionMessages: mockState.sessionMessages,
+    sessionMetas: mockState.sessionMetas,
+    applyRemoteSnapshot: vi.fn(),
+    getSnapshot: vi.fn(() => ({
+      activeSessionId: mockState.activeSessionId.value,
+      sessionMessages: mockState.sessionMessages.value,
+      sessionMetas: mockState.sessionMetas.value,
+    })),
+    getSessionMessages: mockState.getSessionMessages,
+    setSessionMessages: mockState.setSessionMessages,
+  }),
+}))
+
+vi.mock('@proj-airi/stage-ui/stores/chat/stream-store', () => ({
+  useChatStreamStore: () => ({
+    streamingMessage: ref({ role: 'assistant', content: '', slices: [], tool_results: [] }),
+  }),
+}))
+
+vi.mock('@proj-airi/stage-ui/stores/chat', () => ({
+  useChatOrchestratorStore: () => ({
+    sending: ref(false),
+    ingest: mockState.ingest,
+  }),
+}))
+
+vi.mock('@proj-airi/stage-ui/stores/chat/maintenance', () => ({
+  useChatMaintenanceStore: () => ({
+    cleanupMessages: vi.fn(),
+  }),
+}))
+
+vi.mock('@proj-airi/stage-ui/stores/providers', () => ({
+  useProvidersStore: () => ({
+    getProviderInstance: vi.fn(async () => ({ id: 'provider' })),
+  }),
+}))
+
+vi.mock('@proj-airi/stage-ui/stores/modules/consciousness', () => ({
+  useConsciousnessStore: () => ({
+    activeProvider: computed(() => 'provider-id'),
+    activeModel: computed(() => 'model-id'),
+  }),
+}))
+
+vi.mock('./tools/builtin/widgets', () => ({
+  widgetsTools: vi.fn(async () => []),
+}))
+
+vi.mock('./tools/builtin/weather', () => ({
+  weatherTools: vi.fn(async () => []),
+}))
+
+/**
+ * @example
+ * describe('useChatSyncStore authority ingest failures', () => {
+ *   it('persists ingest errors into authoritative session snapshot', async () => {})
+ * })
+ */
+describe('useChatSyncStore authority ingest failures', async () => {
+  const { useChatSyncStore } = await import('./chat-sync')
+
+  beforeEach(() => {
+    setActivePinia(createPinia())
+    MockBroadcastChannel.reset()
+
+    const activeSessionId = ref('session-1')
+    const sessionMessages = ref<Record<string, Array<{ role: string, content: string }>>>({
+      'session-1': [{ role: 'system', content: 'init' }],
+    })
+    const sessionMetas = ref<Record<string, unknown>>({})
+
+    const setSessionMessages = vi.fn((sessionId: string, next: Array<{ role: string, content: string }>) => {
+      sessionMessages.value[sessionId] = next
+    })
+
+    const getSessionMessages = vi.fn((sessionId: string) => sessionMessages.value[sessionId] ?? [])
+
+    const ingest = vi.fn(async () => {
+      throw new Error('Remote sent 403 response: {"error":{"message":"This model is not available in your region.","code":403}}')
+    })
+
+    mockState = {
+      activeSessionId,
+      sessionMessages,
+      sessionMetas,
+      setSessionMessages,
+      getSessionMessages,
+      ingest,
+    }
+
+    vi.stubGlobal('BroadcastChannel', MockBroadcastChannel)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+    MockBroadcastChannel.reset()
+  })
+
+  /**
+   * @example
+   * it('keeps region-availability errors visible for follower windows', async () => {
+   *   // authority receives ingest command failure
+   *   // authoritative session gets role:error entry
+   * })
+   */
+  it('stores command ingest errors in authority session history', async () => {
+    const store = useChatSyncStore()
+    store.initialize('authority')
+
+    const peer = new MockBroadcastChannel('airi:stage-tamagotchi:chat-sync')
+    peer.postMessage({
+      type: 'command',
+      requestId: 'req-1',
+      senderId: 'peer',
+      command: 'ingest',
+      payload: {
+        text: 'hello',
+        sessionId: 'session-1',
+      },
+    })
+
+    await vi.waitFor(() => {
+      expect(mockState.ingest).toHaveBeenCalledTimes(1)
+      expect(mockState.setSessionMessages).toHaveBeenCalledTimes(1)
+    })
+
+    const persistedMessages = mockState.sessionMessages.value['session-1']
+    expect(persistedMessages).toHaveLength(2)
+    expect(persistedMessages[1]?.role).toBe('error')
+    expect(persistedMessages[1]?.content).toContain('This model is not available in your region')
+
+    peer.close()
+    store.dispose()
+  })
+})
diff --git a/apps/stage-tamagotchi/src/renderer/stores/chat-sync.ts b/apps/stage-tamagotchi/src/renderer/stores/chat-sync.ts
index 0f7605ff4..392880899 100644
--- a/apps/stage-tamagotchi/src/renderer/stores/chat-sync.ts
+++ b/apps/stage-tamagotchi/src/renderer/stores/chat-sync.ts
@@ -229,6 +229,18 @@ export const useChatSyncStore = defineStore('stage-tamagotchi:chat-sync', () =>
     chatSession.setSessionMessages(sessionId, nextMessages)
   }
 
+  function appendIngestErrorMessage(payload: IngestCommandPayload, message: string) {
+    const sessionId = payload.sessionId || chatSession.activeSessionId
+    const nextMessages = [
+      ...chatSession.getSessionMessages(sessionId),
+      {
+        role: 'error',
+        content: message,
+      } satisfies ChatHistoryItem,
+    ]
+    chatSession.setSessionMessages(sessionId, nextMessages)
+  }
+
   async function handleCommand(message: Extract<ChatSyncMessage, { type: 'command' }>) {
     if (mode.value !== 'authority')
       return
@@ -259,7 +271,12 @@ export const useChatSyncStore = defineStore('stage-tamagotchi:chat-sync', () =>
       respond(true)
     }
     catch (error) {
-      respond(false, errorMessageFrom(error) ?? 'Unknown chat sync command failure')
+      const errorMessage = errorMessageFrom(error) ?? 'Unknown chat sync command failure'
+
+      if (message.command === 'ingest')
+        appendIngestErrorMessage(message.payload, errorMessage)
+
+      respond(false, errorMessage)
     }
   }