diff --git a/apps/stage-tamagotchi/src/renderer/App.vue b/apps/stage-tamagotchi/src/renderer/App.vue
index 550bf3ace..845388cc4 100644
--- a/apps/stage-tamagotchi/src/renderer/App.vue
+++ b/apps/stage-tamagotchi/src/renderer/App.vue
@@ -79,6 +79,7 @@ const builtinToolsStore = useTamagotchiBuiltinToolsStore()
 const mcpToolsStore = useTamagotchiMcpToolsStore()
 const pluginToolsStore = useTamagotchiPluginToolsStore()
 const syncedPinia = usePiniaSynced()
+chatSessionStore.setCloudSyncOwnership(syncedPinia.isLeader())
 const isSpotlightWindowRoute = initialWindowRoutePath === '/spotlight'
 const isSettingsWindowRoute = initialWindowRoutePath === '/settings' || initialWindowRoutePath.startsWith('/settings/')
 const isEditorWindowRoute = initialWindowRoutePath === '/editor'
@@ -99,7 +100,8 @@ async function refreshPluginRuntimeTools() {
 
 // Every renderer creates the runtime tool stores because every renderer can
 // become the leader. Only the leader discovers tools and keeps executors.
-const stopToolLeadershipListener = syncedPinia.onLeadershipChange((isLeader) => {
+const stopLeadershipListener = syncedPinia.onLeadershipChange((isLeader) => {
+  chatSessionStore.setCloudSyncOwnership(isLeader)
   if (!isLeader)
     return
 
@@ -313,7 +315,7 @@ watch(themeColorsHueDynamic, () => {
 }, { immediate: true })
 
 onUnmounted(() => {
-  stopToolLeadershipListener?.()
+  stopLeadershipListener?.()
   fullStageRuntime?.dispose()
 })
 </script>
diff --git a/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.browser.test.ts b/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.browser.test.ts
new file mode 100644
index 000000000..f6c24e433
--- /dev/null
+++ b/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.browser.test.ts
@@ -0,0 +1,320 @@
+import type { ChatSessionMeta } from '@proj-airi/stage-ui/types/chat-session'
+import type { Component } from 'vue'
+
+import SharedInteractiveArea from '@proj-airi/stage-layouts/components/Layouts/InteractiveArea'
+import MobileInteractiveArea from '@proj-airi/stage-layouts/components/Layouts/MobileInteractiveArea'
+import ChatArea from '@proj-airi/stage-layouts/components/Widgets/ChatArea'
+
+import { PiniaColada } from '@pinia/colada'
+import { useChatStore } from '@proj-airi/stage-ui/stores/chat'
+import { useChatSessionStore } from '@proj-airi/stage-ui/stores/chat/session-store'
+import { useChatStreamStore } from '@proj-airi/stage-ui/stores/chat/stream-store'
+import { createPinia } from 'pinia'
+import { describe, expect, it, vi } from 'vitest'
+import { render } from 'vitest-browser-vue'
+import { userEvent } from 'vitest/browser'
+import { nextTick } from 'vue'
+import { createI18n } from 'vue-i18n'
+import { createMemoryHistory, createRouter } from 'vue-router'
+
+import InteractiveArea from './InteractiveArea.vue'
+
+function createTestI18n() {
+  return createI18n({
+    legacy: false,
+    locale: 'en',
+    missingWarn: false,
+    fallbackWarn: false,
+    messages: { en: {} },
+  })
+}
+
+async function renderArea(component: Component = InteractiveArea) {
+  const sessionB: ChatSessionMeta = {
+    sessionId: 'session-b',
+    userId: 'local',
+    characterId: 'default',
+    createdAt: 1,
+    updatedAt: 1,
+  }
+  const sessionA: ChatSessionMeta = {
+    ...sessionB,
+    sessionId: 'session-a',
+    createdAt: 2,
+    updatedAt: 2,
+  }
+  const pinia = createPinia()
+  pinia.state.value = {
+    'chat-session-selection': { activeSessionId: 'session-b' },
+    'chat-session': {
+      sessionMetas: { 'session-a': sessionA, 'session-b': sessionB },
+      sessionMessages: {
+        'session-a': [{ id: 'system-a', role: 'system', content: 'session A prompt' }],
+        'session-b': [{ id: 'system', role: 'system', content: 'system prompt' }],
+      },
+    },
+  }
+  const router = createRouter({
+    history: createMemoryHistory(),
+    routes: [{ path: '/', component: { template: '<div />' } }],
+  })
+  await router.push('/')
+  await router.isReady()
+
+  const screen = await render(component, {
+    global: { plugins: [pinia, PiniaColada, createTestI18n(), router] },
+  })
+  return {
+    chat: useChatStore(pinia),
+    chatSession: useChatSessionStore(pinia),
+    chatStream: useChatStreamStore(pinia),
+    screen,
+  }
+}
+
+async function submitDraft(screen: Awaited<ReturnType<typeof renderArea>>['screen'], draft: string) {
+  const input = screen.getByRole('textbox')
+  await userEvent.fill(input, draft)
+  await userEvent.click(input)
+  await userEvent.keyboard('{Enter}')
+  return input
+}
+
+describe('interactive area synchronized state', () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743121861
+  it('renders the active synchronized stream through the real chat history for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // A follower received the leader-owned active stream in the real chat
+    // store, but InteractiveArea passed its unrelated foreground stream to
+    // ChatHistory. Mocking either store or component hid that broken binding.
+    const { chat, chatStream, screen } = await renderArea()
+    chat.$patch({
+      activeSendSessionId: 'session-b',
+      activeStreamingMessage: {
+        id: 'follower-b-stream',
+        role: 'assistant',
+        content: 'Follower B live response',
+        slices: [{ type: 'text', text: 'Follower B live response' }],
+        tool_results: [],
+        createdAt: 2,
+      },
+      sending: true,
+    })
+    chatStream.$patch({
+      streamingMessage: {
+        id: 'leader-a-stream',
+        role: 'assistant',
+        content: 'Leader A foreground response',
+        slices: [{ type: 'text', text: 'Leader A foreground response' }],
+        tool_results: [],
+        createdAt: 3,
+      },
+    })
+    await nextTick()
+
+    await expect.element(screen.getByText('Follower B live response')).toBeVisible()
+    await expect.element(screen.getByText('Leader A foreground response')).not.toBeInTheDocument()
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743309235
+  it('scopes the mobile synchronized stream to its local session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // MobileInteractiveArea passed the synchronized global sending state and
+    // foreground stream directly to ChatHistory. A mobile window on session B
+    // therefore rendered the live response from a send targeting session A.
+    const { chat, chatStream, screen } = await renderArea(MobileInteractiveArea)
+    chat.$patch({
+      activeSendSessionId: 'session-a',
+      activeStreamingMessage: {
+        id: 'session-a-stream',
+        role: 'assistant',
+        content: 'Session A live response',
+        slices: [{ type: 'text', text: 'Session A live response' }],
+        tool_results: [],
+        createdAt: 2,
+      },
+      sending: true,
+    })
+    chatStream.$patch({
+      streamingMessage: {
+        id: 'session-a-foreground',
+        role: 'assistant',
+        content: 'Session A live response',
+        slices: [{ type: 'text', text: 'Session A live response' }],
+        tool_results: [],
+        createdAt: 2,
+      },
+    })
+    await nextTick()
+    await expect.element(screen.getByText('Session A live response')).not.toBeInTheDocument()
+
+    chat.$patch({
+      activeSendSessionId: 'session-b',
+      activeStreamingMessage: {
+        id: 'session-b-stream',
+        role: 'assistant',
+        content: 'Session B live response',
+        slices: [{ type: 'text', text: 'Session B live response' }],
+        tool_results: [],
+        createdAt: 3,
+      },
+    })
+    await nextTick()
+    await expect.element(screen.getByText('Session B live response')).toBeVisible()
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743366443
+  it('scopes the stage-web desktop synchronized stream to its local session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // The shared desktop layout derived sending from the target session but
+    // still passed the leader foreground stream to ChatHistory. A web window
+    // on B could therefore append A's live response.
+    const { chat, chatStream, screen } = await renderArea(SharedInteractiveArea)
+    chat.$patch({
+      activeSendSessionId: 'session-b',
+      activeStreamingMessage: {
+        id: 'session-b-web-stream',
+        role: 'assistant',
+        content: 'Session B web response',
+        slices: [{ type: 'text', text: 'Session B web response' }],
+        tool_results: [],
+        createdAt: 2,
+      },
+      sending: true,
+    })
+    chatStream.$patch({
+      streamingMessage: {
+        id: 'session-a-web-foreground',
+        role: 'assistant',
+        content: 'Session A foreground response',
+        slices: [{ type: 'text', text: 'Session A foreground response' }],
+        tool_results: [],
+        createdAt: 3,
+      },
+    })
+    await nextTick()
+
+    await expect.element(screen.getByText('Session B web response')).toBeVisible()
+    await expect.element(screen.getByText('Session A foreground response')).not.toBeInTheDocument()
+  })
+
+  it('routes a stage-web send through the synchronized chat action', async () => {
+    const { chat, screen } = await renderArea(SharedInteractiveArea)
+    const send = vi.spyOn(chat, 'send').mockResolvedValueOnce({ messages: [], sessionId: 'session-b' })
+
+    await submitDraft(screen, 'web follower message')
+
+    await vi.waitFor(() => expect(send).toHaveBeenCalledWith({
+      sessionId: 'session-b',
+      text: 'web follower message',
+    }))
+  })
+
+  it('routes a mobile send through the synchronized chat action', async () => {
+    const { chat, screen } = await renderArea(MobileInteractiveArea)
+    const send = vi.spyOn(chat, 'send').mockResolvedValueOnce({ messages: [], sessionId: 'session-b' })
+
+    await submitDraft(screen, 'mobile follower message')
+
+    await vi.waitFor(() => expect(send).toHaveBeenCalledWith({
+      sessionId: 'session-b',
+      text: 'mobile follower message',
+    }))
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3755530944
+  it('keeps a failed mobile draft out of a newly selected session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Shared layouts restored a rejected send into their component-wide input
+    // without checking whether the window still displayed the target session.
+    const { chat, chatSession, screen } = await renderArea(MobileInteractiveArea)
+    let rejectSend: ((error: Error) => void) | undefined
+    vi.spyOn(chat, 'send').mockImplementationOnce(() => new Promise((_resolve, reject) => {
+      rejectSend = reject
+    }))
+
+    const input = await submitDraft(screen, 'mobile draft from B')
+    chatSession.activeSessionId = 'session-a'
+    rejectSend?.(new Error('send failed'))
+
+    await expect.element(input).toHaveValue('')
+  })
+
+  it('does not restore a deleted-session draft in the shared chat widget', async () => {
+    const { chat, screen } = await renderArea(ChatArea)
+    let rejectSend: ((error: Error) => void) | undefined
+    vi.spyOn(chat, 'send').mockImplementationOnce(() => new Promise((_resolve, reject) => {
+      rejectSend = reject
+    }))
+
+    const input = await submitDraft(screen, 'deleted web draft')
+    rejectSend?.(new Error('Chat session was removed before send completed'))
+
+    await expect.element(input).toHaveValue('')
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3628804992
+  it('does not restore a failed draft into a newly selected session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Failure recovery used the reactive selection instead of the session
+    // captured by the send, so a late rejection could move a draft.
+    const { chat, chatSession, screen } = await renderArea()
+    let rejectSend: ((error: Error) => void) | undefined
+    vi.spyOn(chat, 'send').mockImplementationOnce(() => new Promise((_resolve, reject) => {
+      rejectSend = reject
+    }))
+
+    const input = await submitDraft(screen, 'send from B')
+    await expect.element(input).toHaveValue('')
+    chatSession.activeSessionId = 'session-a'
+    rejectSend?.(new Error('hydrate failed'))
+
+    await expect.element(input).toHaveValue('')
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3629004140
+  it('restores a failed draft when its captured session is still active for Issue #2085', async () => {
+    const { chat, screen } = await renderArea()
+    vi.spyOn(chat, 'send').mockRejectedValueOnce(new Error('send failed'))
+
+    const input = await submitDraft(screen, 'retry this draft')
+    await expect.element(input).toHaveValue('retry this draft')
+  })
+
+  it('keeps a newer draft when an earlier send fails', async () => {
+    // ROOT CAUSE:
+    //
+    // Failure recovery replaced the textarea unconditionally. Text entered
+    // while the request was pending was lost with its attachment previews.
+    const { chat, screen } = await renderArea()
+    let rejectSend: ((error: Error) => void) | undefined
+    vi.spyOn(chat, 'send').mockImplementationOnce(() => new Promise((_resolve, reject) => {
+      rejectSend = reject
+    }))
+
+    const input = await submitDraft(screen, 'first draft')
+    await userEvent.fill(input, 'newer draft')
+    rejectSend?.(new Error('send failed'))
+
+    await expect.element(input).toHaveValue('first draft\nnewer draft')
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743366446
+  it('discards a queued draft when deletion cancels its send for Issue #2085', async () => {
+    const { chat, screen } = await renderArea()
+    let rejectSend: ((error: Error) => void) | undefined
+    vi.spyOn(chat, 'send').mockImplementationOnce(() => new Promise((_resolve, reject) => {
+      rejectSend = reject
+    }))
+
+    const input = await submitDraft(screen, 'discard this deleted draft')
+    rejectSend?.(new Error('Chat session was reset before send could start'))
+
+    await expect.element(input).toHaveValue('')
+  })
+})
diff --git a/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.vue b/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.vue
index ba51f6a8c..62c045bae 100644
--- a/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.vue
+++ b/apps/stage-tamagotchi/src/renderer/components/InteractiveArea.vue
@@ -2,6 +2,7 @@
 import type { ChatToolCallRendererRegistry } from '@proj-airi/stage-ui/components'
 import type { ChatHistoryItem } from '@proj-airi/stage-ui/types/chat'
 
+import { errorMessageFrom } from '@moeru/std'
 import { useStopSpeakingButton } from '@proj-airi/stage-layouts/composables/useStopSpeakingButton'
 import { ChatHistory, JournalPreviewModal } from '@proj-airi/stage-ui/components'
 import { useAnalytics } from '@proj-airi/stage-ui/composables/use-analytics'
@@ -37,9 +38,9 @@ const backgroundStore = useBackgroundStore()
 const journalPreviewStore = useJournalPreviewStore()
 const airiCardStore = useAiriCardStore()
 
-const { messages } = storeToRefs(chatSession)
+const { activeSessionId, messages } = storeToRefs(chatSession)
 const { streamingMessage } = storeToRefs(chatStream)
-const { sending } = storeToRefs(chatStore)
+const { activeSendSessionId, activeStreamingMessage, sending } = storeToRefs(chatStore)
 const { activeCard, activeCardId } = storeToRefs(airiCardStore)
 const { t } = useI18n()
 const { openImagePreview } = journalPreviewStore
@@ -88,6 +89,9 @@ async function handleSend() {
 
   const textToSend = messageInput.value
   const attachmentsToSend = attachments.value.map(att => ({ ...att }))
+  // The active session can change while the cross-window request is pending.
+  // Keep one correlation key for both the send and its failure recovery.
+  const targetSessionId = chatSession.activeSessionId
 
   // optimistic clear
   messageInput.value = ''
@@ -95,7 +99,7 @@ async function handleSend() {
 
   try {
     await chatStore.send({
-      sessionId: chatSession.activeSessionId,
+      sessionId: targetSessionId,
       text: textToSend,
       attachments: attachmentsToSend,
       tools: artistryToolReferences,
@@ -103,10 +107,21 @@ async function handleSend() {
 
     attachmentsToSend.forEach(att => URL.revokeObjectURL(att.url))
   }
-  catch {
-    // restore on failure
-    messageInput.value = textToSend
-    attachments.value = attachmentsToSend
+  catch (error) {
+    const errorMessage = errorMessageFrom(error) ?? String(error)
+    const wasCancelledForDeletedSession
+      = errorMessage.includes('Chat session was reset before send could start')
+        || errorMessage.includes('Chat session was removed before send completed')
+    if (!wasCancelledForDeletedSession && chatSession.activeSessionId === targetSessionId) {
+      const currentDraft = messageInput.value
+      messageInput.value = currentDraft ? `${textToSend}\n${currentDraft}` : textToSend
+      attachments.value = [...attachmentsToSend, ...attachments.value]
+    }
+    else {
+      // This window no longer owns a visible attachment preview, so its Blob
+      // URLs must be released instead of surviving until the window closes.
+      attachmentsToSend.forEach(attachment => URL.revokeObjectURL(attachment.url))
+    }
   }
 }
 
@@ -197,6 +212,10 @@ watch(sendMode, () => {
 
 const historyMessages = computed(() => messages.value as unknown as ChatHistoryItem[])
 const assistantLabel = computed(() => activeCard.value?.name?.trim() || undefined)
+const isActiveSessionSending = computed(() => sending.value && activeSendSessionId.value === activeSessionId.value)
+const visibleStreamingMessage = computed(() => activeSendSessionId.value === activeSessionId.value
+  ? activeStreamingMessage.value
+  : streamingMessage.value)
 
 async function handleDeleteMessage(index: number) {
   const message = messages.value[index]
@@ -252,8 +271,8 @@ async function handleCleanupMessages() {
       <ChatHistory
         :messages="historyMessages"
         :assistant-label="assistantLabel"
-        :sending="sending"
-        :streaming-message="streamingMessage"
+        :sending="isActiveSessionSending"
+        :streaming-message="visibleStreamingMessage"
         :tool-call-renderers="toolCallRenderers"
         @delete-message="handleDeleteMessage($event.index)"
         @retry-message="handleRetryMessage($event.index)"
diff --git a/apps/stage-tamagotchi/vitest.config.ts b/apps/stage-tamagotchi/vitest.config.ts
index 13eb6abff..543ee1aff 100644
--- a/apps/stage-tamagotchi/vitest.config.ts
+++ b/apps/stage-tamagotchi/vitest.config.ts
@@ -3,19 +3,44 @@ import { cwd } from 'node:process'
 import vue from '@vitejs/plugin-vue'
 import Info from 'unplugin-info/vite'
 
+import { playwright } from '@vitest/browser-playwright'
 import { loadEnv } from 'vite'
 import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
+  root: import.meta.dirname,
   plugins: [
     Info(),
     vue(),
   ],
   test: {
     env: loadEnv('test', cwd(), ''),
-    include: ['src/**/*.test.ts', 'scripts/**/*.test.ts'],
-    exclude: ['**/node_modules/**', '**/.git/**'],
-    fileParallelism: false,
-    maxWorkers: 1,
+    projects: [
+      {
+        extends: true,
+        test: {
+          name: 'node',
+          include: ['src/**/*.test.ts', 'scripts/**/*.test.ts'],
+          exclude: ['src/**/*.browser.test.ts', '**/node_modules/**', '**/.git/**'],
+          fileParallelism: false,
+          maxWorkers: 1,
+        },
+      },
+      {
+        extends: true,
+        test: {
+          name: 'browser',
+          include: ['src/**/*.browser.test.ts'],
+          exclude: ['**/node_modules/**', '**/.git/**'],
+          browser: {
+            enabled: true,
+            provider: playwright(),
+            instances: [
+              { browser: 'chromium' },
+            ],
+          },
+        },
+      },
+    ],
   },
 })
diff --git a/apps/stage-tamagotchi/vitest.node.config.ts b/apps/stage-tamagotchi/vitest.node.config.ts
new file mode 100644
index 000000000..174b15aef
--- /dev/null
+++ b/apps/stage-tamagotchi/vitest.node.config.ts
@@ -0,0 +1,20 @@
+import { cwd } from 'node:process'
+
+import vue from '@vitejs/plugin-vue'
+import Info from 'unplugin-info/vite'
+
+import { loadEnv } from 'vite'
+import { defineProject } from 'vitest/config'
+
+export default defineProject({
+  root: import.meta.dirname,
+  plugins: [Info(), vue()],
+  test: {
+    name: 'stage-tamagotchi:node',
+    env: loadEnv('test', cwd(), ''),
+    include: ['src/**/*.test.ts', 'scripts/**/*.test.ts'],
+    exclude: ['src/**/*.browser.test.ts', '**/node_modules/**', '**/.git/**'],
+    fileParallelism: false,
+    maxWorkers: 1,
+  },
+})
diff --git a/apps/stage-web/src/App.vue b/apps/stage-web/src/App.vue
index 54179fc43..96aae0266 100644
--- a/apps/stage-web/src/App.vue
+++ b/apps/stage-web/src/App.vue
@@ -3,6 +3,7 @@ import { OnboardingDialog, OnboardingStepAnalyticsNotice, ToasterRoot } from '@p
 import { useInferencePreload } from '@proj-airi/stage-ui/composables'
 import { useAuthProviderSync } from '@proj-airi/stage-ui/composables/use-auth-provider-sync'
 import { initializeAnalytics, isAnalyticsAvailableInBuild } from '@proj-airi/stage-ui/libs/analytics'
+import { usePiniaSynced } from '@proj-airi/stage-ui/libs/pinia'
 import { useCharacterOrchestratorStore } from '@proj-airi/stage-ui/stores/character'
 import { useChatSessionStore } from '@proj-airi/stage-ui/stores/chat/session-store'
 import { useDisplayModelsStore } from '@proj-airi/stage-ui/stores/display-models'
@@ -33,6 +34,9 @@ const settingsStore = useSettings()
 const settings = storeToRefs(settingsStore)
 const onboardingStore = useOnboardingStore()
 const chatSessionStore = useChatSessionStore()
+const syncedPinia = usePiniaSynced()
+chatSessionStore.setCloudSyncOwnership(syncedPinia.isLeader())
+const stopLeadershipListener = syncedPinia.onLeadershipChange(isLeader => chatSessionStore.setCloudSyncOwnership(isLeader))
 const serverChannelStore = useModsServerChannelStore()
 const characterOrchestratorStore = useCharacterOrchestratorStore()
 const settingsAudioDeviceStore = useSettingsAudioDevice()
@@ -105,6 +109,7 @@ onMounted(async () => {
 })
 
 onUnmounted(() => {
+  stopLeadershipListener()
   contextBridgeStore.dispose()
 })
 
diff --git a/package.json b/package.json
index 2e1293f27..d29ec733f 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,8 @@
     "build:packages": "turbo run build -F=\"./packages/*\"",
     "build:engines": "turbo run build -F=\"./engines/*\"",
     "test": "vitest --coverage",
-    "test:run": "vitest run && pnpm run test-audio-pipelines-transcribe:run && pnpm run test-ui:run",
+    "test:run": "vitest run && pnpm run test-stage-tamagotchi:run && pnpm run test-audio-pipelines-transcribe:run && pnpm run test-ui:run",
+    "test-stage-tamagotchi:run": "vitest run --config apps/stage-tamagotchi/vitest.config.ts --project browser",
     "test-audio-pipelines-transcribe:run": "vitest run --config packages/audio-pipelines-transcribe/vitest.config.ts",
     "test-ui:run": "vitest run --config packages/stage-ui/vitest.config.ts",
     "lint": "moeru-lint .",
diff --git a/packages/core-agent/src/runtime/chat-orchestrator-runtime.test.ts b/packages/core-agent/src/runtime/chat-orchestrator-runtime.test.ts
index 765f63a96..05e106235 100644
--- a/packages/core-agent/src/runtime/chat-orchestrator-runtime.test.ts
+++ b/packages/core-agent/src/runtime/chat-orchestrator-runtime.test.ts
@@ -142,11 +142,6 @@ function createHarness() {
   }
 }
 
-/**
- * @example
- * const runtime = createChatOrchestratorRuntime(deps)
- * await runtime.ingest('hello', { model, chatProvider })
- */
 describe('createChatOrchestratorRuntime', () => {
   // ROOT CAUSE:
   //
@@ -290,10 +285,6 @@ describe('createChatOrchestratorRuntime', () => {
     })
   })
 
-  /**
-   * @example
-   * Hook order and prompt composition stay compatible with the stage-ui facade.
-   */
   it('keeps hook order and appends context prompt to the latest user message', async () => {
     const harness = createHarness()
     harness.contextSnapshot['system:weather'] = [
@@ -447,11 +438,6 @@ describe('createChatOrchestratorRuntime', () => {
     expect(legacyUserMessage.createdAt).toBe(new Date(2026, 3, 25, 18, 47).getTime())
   })
 
-  /**
-   * @example
-   * deps.getSystemPromptSupplement() returns tool guidance.
-   * The runtime appends it to the existing provider system message.
-   */
   it('appends system prompt supplement to the provider system message', async () => {
     const harness = createHarness()
     let composedMessages: Message[] = []
@@ -473,11 +459,6 @@ describe('createChatOrchestratorRuntime', () => {
     })
   })
 
-  /**
-   * @example
-   * A session has only user history.
-   * The runtime creates a provider system message for supplemental guidance.
-   */
   it('creates a system message when only a system prompt supplement is available', async () => {
     const harness = createHarness()
     let composedMessages: Message[] = []
@@ -501,10 +482,6 @@ describe('createChatOrchestratorRuntime', () => {
     expect(composedMessages[1]).toMatchObject({ role: 'user' })
   })
 
-  /**
-   * @example
-   * Runtime telemetry callbacks expose client-visible latency milestones.
-   */
   it('emits telemetry milestones for a successful voice-backed message round', async () => {
     const harness = createHarness()
     harness.monotonicNow.set([100, 150, 250, 400, 460])
@@ -626,10 +603,6 @@ describe('createChatOrchestratorRuntime', () => {
     expect(harness.telemetry.messageRound).toHaveLength(2)
   })
 
-  /**
-   * @example
-   * await expect(runtime.ingest('hello', { model, chatProvider })).rejects.toThrow('provider rejected')
-   */
   it('emits chat activation failure telemetry without raw provider messages', async () => {
     const harness = createHarness()
     harness.stream.mockRejectedValueOnce(new Error('provider rejected with sensitive details'))
@@ -696,10 +669,6 @@ describe('createChatOrchestratorRuntime', () => {
     ])
   })
 
-  /**
-   * @example
-   * Cancelling a queued send rejects only pending work that has not started.
-   */
   it('rejects cancelled queued sends before they start', async () => {
     const harness = createHarness()
     let releaseFirstSend: (() => void) | undefined
@@ -731,10 +700,57 @@ describe('createChatOrchestratorRuntime', () => {
     await firstSend
   })
 
-  /**
-   * @example
-   * A queued send rejects if its captured session generation becomes stale.
-   */
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3714754876
+  it('suppresses completion hooks when an active send session is deleted for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Generation checks protected message mutation during a stream, but the
+    // runtime still emitted completion hooks and success analytics after the
+    // provider returned for a deleted session.
+    const harness = createHarness()
+    const completionHook = vi.fn()
+    harness.runtime.hooks.onStreamEnd(completionHook)
+    harness.runtime.hooks.onAssistantResponseEnd(completionHook)
+    harness.runtime.hooks.onAfterSend(completionHook)
+    harness.runtime.hooks.onAssistantMessage(completionHook)
+    harness.runtime.hooks.onChatTurnComplete(completionHook)
+
+    let finishStream: (() => void) | undefined
+    harness.stream.mockImplementationOnce(async (_model, _chatProvider, _messages, options) => {
+      await new Promise<void>((resolve) => {
+        finishStream = resolve
+      })
+      options?.onUsage?.({
+        inputTokens: 1,
+        outputTokens: 1,
+        totalTokens: 2,
+        source: 'reported',
+      })
+      await options?.onStreamEvent?.({ type: 'text-delta', text: 'deleted reply' })
+      await options?.onStreamEvent?.({ type: 'finish', finishReason: 'stop' })
+    })
+
+    const pendingSend = harness.runtime.ingest('delete this chat', {
+      model: 'gpt-test',
+      chatProvider: provider,
+    })
+
+    await vi.waitFor(() => {
+      expect(harness.stream).toHaveBeenCalledTimes(1)
+    })
+    harness.generation.set(2)
+    finishStream?.()
+    await pendingSend
+
+    expect(completionHook).not.toHaveBeenCalled()
+    expect(harness.assistantAppended).toEqual([])
+    expect(harness.assistantTurns).toEqual([])
+    expect(harness.telemetry.assistantResponseRendered).toEqual([])
+    expect(harness.telemetry.llmGeneration).toEqual([])
+    expect(harness.telemetry.messageRound).toEqual([])
+    expect(harness.telemetry.chatActivationSucceeded).toEqual([])
+  })
+
   it('rejects stale generation sends before they start', async () => {
     const harness = createHarness()
     let releaseFirstSend: (() => void) | undefined
@@ -767,17 +783,14 @@ describe('createChatOrchestratorRuntime', () => {
     expect(harness.stream).toHaveBeenCalledTimes(1)
   })
 
-  /**
-   * @example
-   * runtime.setSending(true)
-   * expect(runtime.getSending()).toBe(true)
-   */
   it('keeps sending externally writable for UI facades', () => {
     const harness = createHarness()
 
     harness.runtime.setSending(true)
     expect(harness.runtime.getSending()).toBe(true)
     expect(harness.stateChanges.at(-1)).toEqual({
+      activeSendSessionId: 'session-1',
+      activeStreamingMessage: undefined,
       sending: true,
       pendingQueuedSendCount: 0,
     })
@@ -785,16 +798,66 @@ describe('createChatOrchestratorRuntime', () => {
     harness.runtime.setSending(false)
     expect(harness.runtime.getSending()).toBe(false)
     expect(harness.stateChanges.at(-1)).toEqual({
+      activeSendSessionId: undefined,
+      activeStreamingMessage: undefined,
+      sending: false,
+      pendingQueuedSendCount: 0,
+    })
+  })
+
+  // https://github.com/moeru-ai/airi/issues/2085
+  it('reports the queued send target while a background session is sending for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Runtime state exposed only a global sending boolean. A window-level sync
+    // layer therefore had to infer the owner from the authority's visible
+    // session, which is wrong when a follower targets a background session.
+    const harness = createHarness()
+    let finishSend: (() => void) | undefined
+    harness.stream.mockImplementationOnce(async (_model, _chatProvider, _messages, options) => {
+      await options?.onStreamEvent?.({ type: 'text-delta', text: 'background reply' })
+      await new Promise<void>((resolve) => {
+        finishSend = resolve
+      })
+    })
+
+    const pendingSend = harness.runtime.ingest('background request', {
+      model: 'gpt-test',
+      chatProvider: provider,
+    }, 'session-2')
+
+    await vi.waitFor(() => {
+      expect(harness.stateChanges).toContainEqual(expect.objectContaining({
+        activeSendSessionId: 'session-2',
+        activeStreamingMessage: expect.objectContaining({
+          role: 'assistant',
+          createdAt: expect.any(Number),
+        }),
+        sending: true,
+        pendingQueuedSendCount: 0,
+      }))
+    })
+    await vi.waitFor(() => {
+      expect(harness.stream).toHaveBeenCalledTimes(1)
+    })
+    await vi.waitFor(() => {
+      expect(harness.stateChanges).toContainEqual(expect.objectContaining({
+        activeSendSessionId: 'session-2',
+        activeStreamingMessage: expect.objectContaining({ content: expect.stringContaining('background') }),
+      }))
+    })
+
+    finishSend?.()
+    await pendingSend
+
+    expect(harness.stateChanges.at(-1)).toEqual({
+      activeSendSessionId: undefined,
+      activeStreamingMessage: undefined,
       sending: false,
       pendingQueuedSendCount: 0,
     })
   })
 
-  /**
-   * @example
-   * const snapshot = runtime.getPendingQueuedSendSnapshot()
-   * expect(snapshot[0].inputType).toBe('input:text')
-   */
   it('returns pending queued send snapshots with public fields', async () => {
     const harness = createHarness()
     let releaseFirstSend: (() => void) | undefined
@@ -852,10 +915,6 @@ describe('createChatOrchestratorRuntime', () => {
     await firstSend
   })
 
-  /**
-   * @example
-   * Attachments, reasoning deltas, and tool events update the assistant builder.
-   */
   it('handles attachments, reasoning deltas, tool events, and assistant finalization', async () => {
     const harness = createHarness()
     let composedMessages: Message[] = []
diff --git a/packages/core-agent/src/runtime/chat-orchestrator-runtime.ts b/packages/core-agent/src/runtime/chat-orchestrator-runtime.ts
index 2a71115f2..c4058a890 100644
--- a/packages/core-agent/src/runtime/chat-orchestrator-runtime.ts
+++ b/packages/core-agent/src/runtime/chat-orchestrator-runtime.ts
@@ -154,6 +154,10 @@ export interface ChatOrchestratorPromptProjection {
 export interface ChatOrchestratorRuntimeState {
   /** Whether the runtime currently owns an active send. */
   sending: boolean
+  /** Session that owns the active send; undefined while the queue is idle. */
+  activeSendSessionId?: string
+  /** Latest assistant stream snapshot owned by the active send session. */
+  activeStreamingMessage?: StreamingAssistantMessage
   /** Number of sends waiting behind the active one. */
   pendingQueuedSendCount: number
 }
@@ -350,19 +354,29 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
   const unwrapMessage = deps.unwrapMessage ?? (<T>(message: T) => message)
 
   let sending = false
+  let activeSendSessionId: string | undefined
+  let activeStreamingMessage: StreamingAssistantMessage | undefined
   let pendingQueuedSends: QueuedSend[] = []
 
   function emitStateChange() {
     deps.onStateChange?.({
       sending,
+      activeSendSessionId,
+      activeStreamingMessage,
       pendingQueuedSendCount: pendingQueuedSends.length,
     })
   }
 
   function setSending(next: boolean) {
-    if (sending === next)
+    const nextActiveSendSessionId = next
+      ? activeSendSessionId ?? deps.getActiveSessionId()
+      : undefined
+    if (sending === next && activeSendSessionId === nextActiveSendSessionId)
       return
     sending = next
+    activeSendSessionId = nextActiveSendSessionId
+    if (!next)
+      activeStreamingMessage = undefined
     emitStateChange()
   }
 
@@ -370,7 +384,22 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
     return sessionId === deps.getActiveSessionId()
   }
 
-  function patchForegroundStream(sessionId: string, message: StreamingAssistantMessage) {
+  function beginStream(sessionId: string, message: StreamingAssistantMessage) {
+    sending = true
+    activeSendSessionId = sessionId
+    activeStreamingMessage = cloneStreamingMessage(message)
+    emitStateChange()
+
+    if (isForegroundSession(sessionId))
+      deps.foregroundStream.patch(cloneStreamingMessage(message))
+  }
+
+  function updateStream(sessionId: string, message: StreamingAssistantMessage) {
+    if (sessionId === activeSendSessionId) {
+      activeStreamingMessage = cloneStreamingMessage(message)
+      emitStateChange()
+    }
+
     if (isForegroundSession(sessionId))
       deps.foregroundStream.patch(cloneStreamingMessage(message))
   }
@@ -481,8 +510,6 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
     if (shouldAbort())
       return
 
-    setSending(true)
-
     const buildingMessage: StreamingAssistantMessage = {
       role: 'assistant',
       content: '',
@@ -491,7 +518,7 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
       createdAt: now(),
       id: assistantMessageId,
     }
-    patchForegroundStream(sessionId, buildingMessage)
+    beginStream(sessionId, buildingMessage)
     const sendSource = options.input ? 'voice' : 'text'
     const activeProvider = deps.getActiveProvider?.() ?? ''
     // The user message is the durable start of a round, so its ID also serves
@@ -604,7 +631,7 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
                 text: speechOnly,
               })
             }
-            patchForegroundStream(sessionId, buildingMessage)
+            updateStream(sessionId, buildingMessage)
           }
         },
         onSpecial: async (special) => {
@@ -624,7 +651,7 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
             speech: finalCategorization.speech,
             reasoning: reasoningContentField || finalCategorization.reasoning,
           }
-          patchForegroundStream(sessionId, buildingMessage)
+          updateStream(sessionId, buildingMessage)
         },
         // The parser keeps its own marker-safety tail. Emit each safe literal
         // chunk so slow providers update the chat before they reach 24 characters.
@@ -638,13 +665,13 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
               return
             if (ctx.data.type === 'tool-call') {
               buildingMessage.slices.push(ctx.data)
-              patchForegroundStream(sessionId, buildingMessage)
+              updateStream(sessionId, buildingMessage)
               return
             }
 
             if (ctx.data.type === 'tool-call-result') {
               buildingMessage.tool_results.push(ctx.data)
-              patchForegroundStream(sessionId, buildingMessage)
+              updateStream(sessionId, buildingMessage)
             }
           },
         ],
@@ -749,6 +776,9 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
             providerTranscript = structuredClone(currentTurnMessages)
         },
         onUsage: (usage) => {
+          if (shouldAbort())
+            return
+
           generationUsage = usage
           deps.onLlmGeneration?.({
             ...correlation,
@@ -761,6 +791,9 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
           })
         },
         onStreamEvent: async (event: StreamEvent) => {
+          if (shouldAbort())
+            return
+
           switch (event.type) {
             case 'tool-call':
               toolCallQueue.enqueue({
@@ -812,7 +845,7 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
                 = Math.floor(nextReasoning.length / REASONING_UI_FLUSH_CHUNK_SIZE)
                   > Math.floor(reasoning.length / REASONING_UI_FLUSH_CHUNK_SIZE)
               if (!reasoning || crossesBoundary)
-                patchForegroundStream(sessionId, buildingMessage)
+                updateStream(sessionId, buildingMessage)
               break
             }
             case 'finish':
@@ -823,7 +856,16 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
         },
       })
 
+      // Session generation is the lifecycle correlation key. Re-check it
+      // after every awaited completion boundary so deleting a session while a
+      // plugin hook runs cannot leak later hooks or success analytics.
+      if (shouldAbort())
+        return
+
       await parser.end()
+      if (shouldAbort())
+        return
+
       buildingMessage.providerTranscript = providerTranscript
       deps.onAssistantResponseRendered?.({
         ...correlation,
@@ -841,17 +883,29 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
         })
       }
 
+      if (shouldAbort())
+        return
       await hooks.emitStreamEndHooks(streamingMessageContext)
+      if (shouldAbort())
+        return
       await hooks.emitAssistantResponseEndHooks(fullText, streamingMessageContext)
 
+      if (shouldAbort())
+        return
       await hooks.emitAfterSendHooks(sendingMessage, streamingMessageContext)
+      if (shouldAbort())
+        return
       await hooks.emitAssistantMessageHooks({ ...buildingMessage }, fullText, streamingMessageContext)
+      if (shouldAbort())
+        return
       await hooks.emitChatTurnCompleteHooks({
         output: { ...buildingMessage },
         outputText: fullText,
         toolCalls: sessionMessagesForSend.filter(msg => msg.role === 'tool') as ToolMessage[],
       }, streamingMessageContext)
 
+      if (shouldAbort())
+        return
       deps.onAssistantTurnReady?.({
         messageText: fullText,
         sessionMessages: sessionMessagesForSend,
@@ -880,6 +934,9 @@ export function createChatOrchestratorRuntime(deps: ChatOrchestratorRuntimeDeps)
       }
     }
     catch (error) {
+      if (isStaleGeneration())
+        return
+
       console.error('Error sending message:', error)
       deps.onMessageRoundFailed?.({
         ...correlation,
diff --git a/packages/stage-layouts/src/components/Layouts/InteractiveArea.vue b/packages/stage-layouts/src/components/Layouts/InteractiveArea.vue
index 66d66c74e..81ef5257c 100644
--- a/packages/stage-layouts/src/components/Layouts/InteractiveArea.vue
+++ b/packages/stage-layouts/src/components/Layouts/InteractiveArea.vue
@@ -6,6 +6,7 @@ import { useAnalytics } from '@proj-airi/stage-ui/composables/use-analytics'
 import { useChatStore } from '@proj-airi/stage-ui/stores/chat'
 import { useChatSessionStore } from '@proj-airi/stage-ui/stores/chat/session-store'
 import { useChatStreamStore } from '@proj-airi/stage-ui/stores/chat/stream-store'
+import { useContextBridgeStore } from '@proj-airi/stage-ui/stores/mods/api/context-bridge'
 import { useDeferredMount } from '@proj-airi/ui'
 import { storeToRefs } from 'pinia'
 import { computed, ref } from 'vue'
@@ -17,18 +18,30 @@ import ChatContainer from '../Widgets/ChatContainer.vue'
 import { useChatToolCallRerun } from '../../composables/useChatToolCallRerun'
 
 const { isReady } = useDeferredMount()
-const { sending } = storeToRefs(useChatStore())
-const { messages } = storeToRefs(useChatSessionStore())
+const { activeSendSessionId, activeStreamingMessage, sending } = storeToRefs(useChatStore())
+const { activeSessionId, messages } = storeToRefs(useChatSessionStore())
 const { streamingMessage } = storeToRefs(useChatStreamStore())
+const { isReceivingRemoteStream } = storeToRefs(useContextBridgeStore())
 
 const isLoading = ref(true)
 const historyMessages = computed(() => messages.value as unknown as ChatHistoryItem[])
+const isActiveSessionSending = computed(() => (
+  (sending.value && activeSendSessionId.value === activeSessionId.value)
+  || isReceivingRemoteStream.value
+))
+const visibleStreamingMessage = computed(() => activeSendSessionId.value === activeSessionId.value
+  ? activeStreamingMessage.value
+  : streamingMessage.value)
 const { trackChatMessageDeleted } = useAnalytics()
 const { rerunToolCall } = useChatToolCallRerun()
 
-function handleDeleteMessage(index: number) {
+async function handleDeleteMessage(index: number) {
   const message = messages.value[index]
-  messages.value = messages.value.filter((_, messageIndex) => messageIndex !== index)
+  await useChatSessionStore().deleteMessage({
+    sessionId: activeSessionId.value,
+    messageId: message?.id,
+    index,
+  })
   trackChatMessageDeleted({
     source: 'history',
     message_role: message?.role ?? 'unknown',
@@ -51,8 +64,8 @@ function handleDeleteMessage(index: number) {
           <ChatHistory
             v-if="isReady"
             :messages="historyMessages"
-            :sending="sending"
-            :streaming-message="streamingMessage"
+            :sending="isActiveSessionSending"
+            :streaming-message="visibleStreamingMessage"
             h-full
             variant="desktop"
             @delete-message="handleDeleteMessage($event.index)"
diff --git a/packages/stage-layouts/src/components/Layouts/MobileInteractiveArea.vue b/packages/stage-layouts/src/components/Layouts/MobileInteractiveArea.vue
index 43a60d68e..d13783cef 100644
--- a/packages/stage-layouts/src/components/Layouts/MobileInteractiveArea.vue
+++ b/packages/stage-layouts/src/components/Layouts/MobileInteractiveArea.vue
@@ -1,6 +1,5 @@
 <script setup lang="ts">
 import type { ChatHistoryItem } from '@proj-airi/stage-ui/types/chat'
-import type { ChatProvider } from '@xsai-ext/providers/utils'
 
 import { errorMessageFrom } from '@moeru/std'
 import { isStageTamagotchi } from '@proj-airi/stage-shared'
@@ -14,9 +13,7 @@ import { useChatMaintenanceStore } from '@proj-airi/stage-ui/stores/chat/mainten
 import { useChatSessionStore } from '@proj-airi/stage-ui/stores/chat/session-store'
 import { useChatStreamStore } from '@proj-airi/stage-ui/stores/chat/stream-store'
 import { useL2dViewControl } from '@proj-airi/stage-ui/stores/live2d'
-import { useConsciousnessStore } from '@proj-airi/stage-ui/stores/modules/consciousness'
-import { useProviderConfigStore } from '@proj-airi/stage-ui/stores/providers/config'
-import { useProviderStore } from '@proj-airi/stage-ui/stores/providers/provider'
+import { useContextBridgeStore } from '@proj-airi/stage-ui/stores/mods/api/context-bridge'
 import { useSettings, useSettingsAudioDevice } from '@proj-airi/stage-ui/stores/settings'
 import { BasicTextarea, useTheme } from '@proj-airi/ui'
 import { useResizeObserver, useScreenSafeArea } from '@vueuse/core'
@@ -39,16 +36,28 @@ const chatOrchestrator = useChatStore()
 const chatSession = useChatSessionStore()
 const chatStream = useChatStreamStore()
 const { cleanupMessages } = useChatMaintenanceStore()
-const { messages } = storeToRefs(chatSession)
+const { activeSessionId, messages } = storeToRefs(chatSession)
 const { streamingMessage } = storeToRefs(chatStream)
-const { sending } = storeToRefs(chatOrchestrator)
+const { activeSendSessionId, activeStreamingMessage, sending } = storeToRefs(chatOrchestrator)
+const { isReceivingRemoteStream } = storeToRefs(useContextBridgeStore())
 const historyMessages = computed(() => messages.value as unknown as ChatHistoryItem[])
+const isActiveSessionSending = computed(() => (
+  (sending.value && activeSendSessionId.value === activeSessionId.value)
+  || isReceivingRemoteStream.value
+))
+const visibleStreamingMessage = computed(() => activeSendSessionId.value === activeSessionId.value
+  ? activeStreamingMessage.value
+  : streamingMessage.value)
 const { trackChatMessageDeleted, trackChatMessagesCleared } = useAnalytics()
 const { rerunToolCall } = useChatToolCallRerun()
 
-function handleDeleteMessage(index: number) {
+async function handleDeleteMessage(index: number) {
   const message = messages.value[index]
-  messages.value = messages.value.filter((_, messageIndex) => messageIndex !== index)
+  await chatSession.deleteMessage({
+    sessionId: activeSessionId.value,
+    messageId: message?.id,
+    index,
+  })
   trackChatMessageDeleted({
     source: 'history',
     message_role: message?.role ?? 'unknown',
@@ -70,17 +79,12 @@ const backgroundDialogOpen = ref(false)
 const sessionsDrawerOpen = ref(false)
 
 const screenSafeArea = useScreenSafeArea()
-const providersStore = useProviderStore()
-const providerStore = useProviderConfigStore()
-const { activeProvider, activeModel } = storeToRefs(useConsciousnessStore())
-
 useResizeObserver(document.documentElement, () => screenSafeArea.update())
 const { themeColorsHueDynamic } = storeToRefs(useSettings())
 const { viewControlsEnabled: l2dViewCtrlEnabled } = useL2dViewControl()
 const { viewControlsEnabled: threeViewCtrlEnabled } = useThreeViewControl()
 const settingsAudioDevice = useSettingsAudioDevice()
 const { enabled, stream } = storeToRefs(settingsAudioDevice)
-const { ingest, onAfterMessageComposed } = chatOrchestrator
 const { t } = useI18n()
 const { audioContext } = useAudioContext()
 const { startAnalyzer, stopAnalyzer } = useAudioAnalyzer()
@@ -112,23 +116,24 @@ async function handleSend() {
   }
 
   const textToSend = messageInput.value
+  const targetSessionId = chatSession.activeSessionId
   messageInput.value = ''
 
   try {
-    const providerConfig = providerStore.getProviderConfig(activeProvider.value)
-
-    await ingest(textToSend, {
-      chatProvider: await providersStore.getProviderInstance(activeProvider.value) as ChatProvider,
-      model: activeModel.value,
-      providerConfig,
+    await chatOrchestrator.send({
+      sessionId: targetSessionId,
+      text: textToSend,
     })
   }
   catch (error) {
-    messageInput.value = textToSend
-    chatSession.appendSessionMessage(chatSession.activeSessionId, {
-      role: 'error',
-      content: errorMessageFrom(error) ?? 'Failed to send message',
-    })
+    const errorMessage = errorMessageFrom(error) ?? String(error)
+    const wasCancelledForDeletedSession
+      = errorMessage.includes('Chat session was reset before send could start')
+        || errorMessage.includes('Chat session was removed before send completed')
+    if (!wasCancelledForDeletedSession && chatSession.activeSessionId === targetSessionId) {
+      const currentDraft = messageInput.value
+      messageInput.value = currentDraft ? `${textToSend}\n${currentDraft}` : textToSend
+    }
   }
 }
 
@@ -158,9 +163,6 @@ watch([enabled, stream], () => {
   setupAnalyzer()
 }, { immediate: true })
 
-onAfterMessageComposed(async () => {
-})
-
 onUnmounted(() => {
   teardownAnalyzer()
 })
@@ -179,8 +181,8 @@ onMounted(() => {
           v-if="!threeViewCtrlEnabled && !l2dViewCtrlEnabled"
           variant="mobile"
           :messages="historyMessages"
-          :sending="sending"
-          :streaming-message="streamingMessage"
+          :sending="isActiveSessionSending"
+          :streaming-message="visibleStreamingMessage"
           max-w="[calc(100%-3.5rem)]"
           w-full self-start pb-3 pl-3
           class="chat-history"
diff --git a/packages/stage-layouts/src/components/Widgets/ChatArea.vue b/packages/stage-layouts/src/components/Widgets/ChatArea.vue
index 05a121024..6f69f4351 100644
--- a/packages/stage-layouts/src/components/Widgets/ChatArea.vue
+++ b/packages/stage-layouts/src/components/Widgets/ChatArea.vue
@@ -1,6 +1,4 @@
 <script setup lang="ts">
-import type { ChatProvider } from '@xsai-ext/providers/utils'
-
 import { errorMessageFrom } from '@moeru/std'
 import { isStageTamagotchi } from '@proj-airi/stage-shared'
 import { HearingConfig } from '@proj-airi/stage-ui/components/scenarios/dialogs/audio-input/index'
@@ -8,9 +6,6 @@ import { useAudioAnalyzer } from '@proj-airi/stage-ui/composables'
 import { useAudioContext } from '@proj-airi/stage-ui/stores/audio'
 import { useChatStore } from '@proj-airi/stage-ui/stores/chat'
 import { useChatSessionStore } from '@proj-airi/stage-ui/stores/chat/session-store'
-import { useConsciousnessStore } from '@proj-airi/stage-ui/stores/modules/consciousness'
-import { useProviderConfigStore } from '@proj-airi/stage-ui/stores/providers/config'
-import { useProviderStore } from '@proj-airi/stage-ui/stores/providers/provider'
 import { useSettings, useSettingsAudioDevice } from '@proj-airi/stage-ui/stores/settings'
 import { BasicTextarea } from '@proj-airi/ui'
 import { useLocalStorage } from '@vueuse/core'
@@ -34,17 +29,12 @@ type SendMode = (typeof SEND_MODES)[number]
 const sendMode = useLocalStorage<SendMode>('ui/chat/settings/send-mode', 'enter')
 const lastEnterTime = ref(0)
 
-const providersStore = useProviderStore()
-
-const providerStore = useProviderConfigStore()
-const { activeProvider, activeModel } = storeToRefs(useConsciousnessStore())
 const { themeColorsHueDynamic } = storeToRefs(useSettings())
 
 const { askPermission } = useSettingsAudioDevice()
 const { enabled, stream } = storeToRefs(useSettingsAudioDevice())
 const chatOrchestrator = useChatStore()
 const chatSession = useChatSessionStore()
-const { ingest, onAfterMessageComposed } = chatOrchestrator
 const { audioContext } = useAudioContext()
 const { t } = useI18n()
 const sendModeLabels = computed<Record<SendMode, string>>(() => ({
@@ -68,24 +58,24 @@ async function handleSend() {
   }
 
   const textToSend = messageInput.value
+  const targetSessionId = chatSession.activeSessionId
   messageInput.value = ''
 
   try {
-    const providerConfig = providerStore.getProviderConfig(activeProvider.value)
-
-    await ingest(textToSend, {
-      chatProvider: await providersStore.getProviderInstance(activeProvider.value) as ChatProvider,
-      model: activeModel.value,
-      providerConfig,
+    await chatOrchestrator.send({
+      sessionId: targetSessionId,
+      text: textToSend,
     })
   }
   catch (error) {
-    // preserve any user input when failed to send the message
-    messageInput.value = [textToSend, messageInput.value.trim()].filter(Boolean).join(' ')
-    chatSession.appendSessionMessage(chatSession.activeSessionId, {
-      role: 'error',
-      content: errorMessageFrom(error) ?? 'Failed to send message',
-    })
+    const errorMessage = errorMessageFrom(error) ?? String(error)
+    const wasCancelledForDeletedSession
+      = errorMessage.includes('Chat session was reset before send could start')
+        || errorMessage.includes('Chat session was removed before send completed')
+    if (!wasCancelledForDeletedSession && chatSession.activeSessionId === targetSessionId) {
+      const currentDraft = messageInput.value
+      messageInput.value = currentDraft ? `${textToSend}\n${currentDraft}` : textToSend
+    }
   }
 }
 
@@ -135,9 +125,6 @@ watch(hearingPopoverOpen, async (value) => {
   }
 })
 
-onAfterMessageComposed(async () => {
-})
-
 const { startAnalyzer, stopAnalyzer } = useAudioAnalyzer()
 let analyzerSource: MediaStreamAudioSourceNode | undefined
 
diff --git a/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.browser.test.ts b/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.browser.test.ts
new file mode 100644
index 000000000..85f6cbdba
--- /dev/null
+++ b/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.browser.test.ts
@@ -0,0 +1,104 @@
+import type { ChatSessionMeta } from '../../../../types/chat-session'
+
+import { describe, expect, it } from 'vitest'
+import { render } from 'vitest-browser-vue'
+import { defineComponent, ref } from 'vue'
+import { createI18n } from 'vue-i18n'
+
+import SessionsDialog from './sessions-dialog.vue'
+
+function createTestI18n() {
+  return createI18n({
+    legacy: false,
+    locale: 'en',
+    messages: {
+      en: {
+        stage: {
+          chat: {
+            sessions: {
+              'title': 'Chats',
+              'new': 'New chat',
+              'empty': 'No chats',
+              'delete': 'Delete',
+              'cloud-badge': 'Cloud synced',
+            },
+          },
+        },
+      },
+    },
+  })
+}
+
+function sessionMeta(sessionId: string, updatedAt: number): ChatSessionMeta {
+  return {
+    sessionId,
+    characterId: 'default',
+    userId: 'local',
+    createdAt: updatedAt,
+    updatedAt,
+  }
+}
+
+function createHarness() {
+  return defineComponent({
+    name: 'SessionsDialogHarness',
+    components: { SessionsDialog },
+    setup() {
+      const created = ref(0)
+      const selected = ref('none')
+      const deleted = ref('none')
+
+      return {
+        created,
+        deleted,
+        selected,
+        rows: [
+          { meta: sessionMeta('session-one', 2), preview: 'First chat', isActive: true, updatedAtLabel: 'now' },
+          { meta: sessionMeta('session-two', 1), preview: 'Second chat', isActive: false, updatedAtLabel: 'yesterday' },
+        ],
+      }
+    },
+    template: `
+      <SessionsDialog
+        :open="true"
+        :rows="rows"
+        :is-desktop="false"
+        :is-creating-session="false"
+        mobile-padding-bottom="24px"
+        @new-session="created += 1"
+        @select-session="selected = $event"
+        @delete-session="deleted = $event"
+      />
+      <output aria-label="created-session-count">{{ created }}</output>
+      <output aria-label="selected-session-id">{{ selected }}</output>
+      <output aria-label="deleted-session-id">{{ deleted }}</output>
+    `,
+  })
+}
+
+describe('sessions dialog actions', () => {
+  // https://github.com/moeru-ai/airi/issues/2085
+  it('keeps add, switch, and delete actions independent for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Vaul handled every pointer release on DrawerContent, including releases
+    // from its action buttons, and unmounted the sheet before `click` ran.
+    // The replacement uses a Reka dialog surface whose buttons emit one action
+    // each without a competing gesture-release lifecycle.
+    const screen = await render(createHarness(), {
+      global: {
+        plugins: [createTestI18n()],
+      },
+    })
+
+    await screen.getByRole('button', { name: 'New chat' }).click()
+    await expect.element(screen.getByLabelText('created-session-count')).toHaveTextContent('1')
+
+    await screen.getByRole('button', { name: 'Delete: Second chat' }).click()
+    await expect.element(screen.getByLabelText('deleted-session-id')).toHaveTextContent('session-two')
+    await expect.element(screen.getByLabelText('selected-session-id')).toHaveTextContent('none')
+
+    await screen.getByRole('button', { name: 'First chat now' }).click()
+    await expect.element(screen.getByLabelText('selected-session-id')).toHaveTextContent('session-one')
+  })
+})
diff --git a/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.vue b/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.vue
new file mode 100644
index 000000000..091a9cb76
--- /dev/null
+++ b/packages/stage-ui/src/components/scenarios/chat/components/sessions-dialog.vue
@@ -0,0 +1,132 @@
+<script setup lang="ts">
+import type { ChatSessionMeta } from '../../../../types/chat-session'
+
+import { DialogContent, DialogOverlay, DialogPortal, DialogRoot, DialogTitle } from 'reka-ui'
+import { useI18n } from 'vue-i18n'
+
+interface SessionRow {
+  meta: ChatSessionMeta
+  preview: string
+  isActive: boolean
+  updatedAtLabel: string
+}
+
+interface Props {
+  open: boolean
+  rows: SessionRow[]
+  isDesktop: boolean
+  isCreatingSession: boolean
+  mobilePaddingBottom: string
+}
+
+defineProps<Props>()
+
+const emit = defineEmits<{
+  'deleteSession': [sessionId: string]
+  'newSession': []
+  'selectSession': [sessionId: string]
+  'update:open': [open: boolean]
+}>()
+
+const { t } = useI18n()
+</script>
+
+<template>
+  <DialogRoot :open="open" @update:open="value => emit('update:open', value)">
+    <slot name="trigger" />
+    <DialogPortal>
+      <DialogOverlay
+        :class="[
+          'fixed inset-0 z-[9999] bg-black/50 backdrop-blur-sm',
+          'data-[state=closed]:animate-fadeOut data-[state=open]:animate-fadeIn',
+        ]"
+      />
+      <DialogContent
+        :aria-describedby="undefined"
+        :class="[
+          'fixed z-[9999] flex flex-col overflow-hidden bg-white/95 shadow-xl outline-none backdrop-blur-md dark:bg-neutral-900/95',
+          isDesktop
+            ? 'left-1/2 top-1/2 max-h-[80dvh] max-w-md w-[92dvw] rounded-2xl -translate-x-1/2 -translate-y-1/2 data-[state=closed]:animate-contentHide data-[state=open]:animate-contentShow'
+            : 'bottom-0 left-0 right-0 max-h-[85dvh] rounded-t-[32px]',
+        ]"
+        :style="isDesktop ? undefined : { paddingBottom: mobilePaddingBottom }"
+      >
+        <div
+          v-if="!isDesktop"
+          :class="['mx-auto mt-3 h-1.5 w-12 shrink-0 rounded-full bg-neutral-400 dark:bg-neutral-600']"
+          aria-hidden="true"
+        />
+        <div :class="['flex min-h-0 flex-1 flex-col']">
+          <div :class="['flex items-center justify-between px-5 pt-5 pb-3']">
+            <DialogTitle :class="['text-base font-medium text-neutral-700 dark:text-neutral-200']">
+              {{ t('stage.chat.sessions.title') }}
+            </DialogTitle>
+            <button
+              type="button"
+              :class="[
+                'rounded-lg px-3 py-1.5 text-xs font-medium',
+                'bg-primary-100/60 text-primary-700 dark:bg-primary-900/40 dark:text-primary-200',
+                'hover:bg-primary-200/70 dark:hover:bg-primary-800/50',
+                'transition-colors',
+              ]"
+              :disabled="isCreatingSession"
+              @click="emit('newSession')"
+            >
+              {{ t('stage.chat.sessions.new') }}
+            </button>
+          </div>
+          <div :class="['flex-1 overflow-y-auto px-2 pb-4']">
+            <div v-if="rows.length === 0" :class="['p-6 text-center text-sm text-neutral-500 dark:text-neutral-400']">
+              {{ t('stage.chat.sessions.empty') }}
+            </div>
+            <div
+              v-for="row in rows"
+              :key="row.meta.sessionId"
+              :class="[
+                'group relative mb-1 w-full rounded-xl transition-colors',
+                row.isActive
+                  ? 'bg-primary-100/70 dark:bg-primary-900/40'
+                  : 'hover:bg-neutral-100/80 dark:hover:bg-neutral-800/60',
+              ]"
+            >
+              <button
+                type="button"
+                :class="['w-full flex flex-col gap-1 px-3 py-3 text-left outline-none']"
+                @click="emit('selectSession', row.meta.sessionId)"
+              >
+                <div :class="['flex items-center gap-2 text-sm font-medium text-neutral-700 dark:text-neutral-200']">
+                  <span :class="['flex-1 truncate']">{{ row.preview }}</span>
+                  <span
+                    v-if="row.meta.cloudChatId"
+                    :class="['shrink-0 rounded px-1.5 py-0.5 text-[10px] uppercase tracking-wide', 'bg-emerald-500/15 text-emerald-700 dark:text-emerald-300']"
+                    :title="t('stage.chat.sessions.cloud-badge')"
+                  >
+                    cloud
+                  </span>
+                  <span :class="['w-7']" />
+                </div>
+                <div :class="['text-[11px] text-neutral-500 dark:text-neutral-400']">
+                  {{ row.updatedAtLabel }}
+                </div>
+              </button>
+              <button
+                type="button"
+                :class="[
+                  'absolute right-2 top-2 z-10 h-7 w-7 flex items-center justify-center rounded-md',
+                  'opacity-100 md:opacity-0 md:group-hover:opacity-100 focus:opacity-100',
+                  'text-neutral-400 hover:bg-red-500/10 hover:text-red-500',
+                  'transition-opacity duration-150',
+                ]"
+                :aria-label="`${t('stage.chat.sessions.delete')}: ${row.preview}`"
+                :title="t('stage.chat.sessions.delete')"
+                @click.stop="emit('deleteSession', row.meta.sessionId)"
+              >
+                <div class="i-solar:trash-bin-trash-bold-duotone h-4 w-4" />
+              </button>
+            </div>
+          </div>
+        </div>
+      </DialogContent>
+    </DialogPortal>
+  </DialogRoot>
+</template>
diff --git a/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.browser.test.ts b/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.browser.test.ts
new file mode 100644
index 000000000..301b399e1
--- /dev/null
+++ b/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.browser.test.ts
@@ -0,0 +1,149 @@
+import type { ChatSessionMeta } from '../../../../types/chat-session'
+
+import { PiniaColada } from '@pinia/colada'
+import { createPinia } from 'pinia'
+import { describe, expect, it, vi } from 'vitest'
+import { render } from 'vitest-browser-vue'
+import { createI18n } from 'vue-i18n'
+
+import SessionsDrawer from './sessions-drawer.vue'
+
+import { useChatStore } from '../../../../stores/chat'
+import { useChatSessionStore } from '../../../../stores/chat/session-store'
+
+function createTestI18n() {
+  return createI18n({
+    legacy: false,
+    locale: 'en',
+    missingWarn: false,
+    fallbackWarn: false,
+    messages: {
+      en: {
+        stage: {
+          chat: {
+            sessions: {
+              'title': 'Chats',
+              'new': 'New chat',
+              'empty': 'No chats',
+              'delete': 'Delete',
+              'cloud-badge': 'Cloud synced',
+            },
+          },
+        },
+      },
+    },
+  })
+}
+
+function sessionMeta(sessionId: string, title: string, updatedAt: number): ChatSessionMeta {
+  return {
+    sessionId,
+    title,
+    characterId: 'default',
+    userId: 'local',
+    createdAt: updatedAt,
+    updatedAt,
+  }
+}
+
+function createSessionsPinia() {
+  const pinia = createPinia()
+  pinia.state.value = {
+    'chat-session-selection': {
+      activeSessionId: 'session-b',
+    },
+    'chat-session': {
+      sessionMetas: {
+        'session-a': sessionMeta('session-a', 'Chat A', 1),
+        'session-b': sessionMeta('session-b', 'Chat B', 3),
+        'session-c': sessionMeta('session-c', 'Chat C', 2),
+      },
+      sessionMessages: {
+        'session-a': [],
+        'session-b': [],
+        'session-c': [],
+      },
+    },
+  }
+  return pinia
+}
+
+describe('sessions drawer orchestration', () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743073795
+  it('preserves a newer selection while active-session deletion is pending for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Deletion captured that B was active, then unconditionally selected its
+    // fallback after the asynchronous leader action completed. A user choice
+    // of C made during that await was therefore overwritten by stale work.
+    const pinia = createSessionsPinia()
+
+    const screen = await render(SessionsDrawer, {
+      props: { modelValue: false },
+      global: {
+        plugins: [pinia, PiniaColada, createTestI18n()],
+      },
+    })
+    const chatSession = useChatSessionStore(pinia)
+    const chat = useChatStore(pinia)
+    let resolveDelete: (() => void) | undefined
+    vi.spyOn(chat, 'deleteSession').mockImplementationOnce(() => new Promise((resolve) => {
+      resolveDelete = resolve
+    }))
+    vi.spyOn(chatSession, 'loadSession').mockResolvedValue(true)
+    vi.spyOn(chatSession, 'setActiveSession').mockImplementation(async (sessionId) => {
+      chatSession.activeSessionId = sessionId
+    })
+    await screen.rerender({ modelValue: true })
+
+    await screen.getByRole('button', { name: 'Delete: Chat B' }).click()
+    await vi.waitFor(() => expect(chat.deleteSession).toHaveBeenCalledWith('session-b'))
+
+    await screen.getByRole('button', { name: /^Chat C / }).click()
+    expect(chatSession.activeSessionId).toBe('session-c')
+
+    resolveDelete?.()
+    await vi.waitFor(() => expect(chatSession.setActiveSession).toHaveBeenCalledTimes(1))
+
+    expect(chatSession.setActiveSession).toHaveBeenLastCalledWith('session-c')
+    expect(chatSession.activeSessionId).toBe('session-c')
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743221030
+  it('preserves a newer selection while session creation is pending for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // New-session creation awaited leader persistence, then unconditionally
+    // selected its result. Session rows stay enabled during that wait, so a
+    // newer row selection was overwritten when creation eventually resolved.
+    const pinia = createSessionsPinia()
+    const screen = await render(SessionsDrawer, {
+      props: { modelValue: false },
+      global: {
+        plugins: [pinia, PiniaColada, createTestI18n()],
+      },
+    })
+    const chatSession = useChatSessionStore(pinia)
+    let resolveCreate: ((sessionId: string) => void) | undefined
+    vi.spyOn(chatSession, 'createSession').mockImplementationOnce(() => new Promise((resolve) => {
+      resolveCreate = resolve
+    }))
+    vi.spyOn(chatSession, 'loadSession').mockResolvedValue(true)
+    vi.spyOn(chatSession, 'setActiveSession').mockImplementation(async (sessionId) => {
+      chatSession.activeSessionId = sessionId
+    })
+    await screen.rerender({ modelValue: true })
+
+    await screen.getByRole('button', { name: 'New chat' }).click()
+    await vi.waitFor(() => expect(chatSession.createSession).toHaveBeenCalledWith('default', { setActive: false }))
+
+    await screen.getByRole('button', { name: /^Chat C / }).click()
+    expect(chatSession.activeSessionId).toBe('session-c')
+
+    resolveCreate?.('session-new')
+    await vi.waitFor(() => expect(chatSession.setActiveSession).toHaveBeenCalledTimes(1))
+
+    expect(chatSession.setActiveSession).toHaveBeenLastCalledWith('session-c')
+    expect(chatSession.activeSessionId).toBe('session-c')
+  })
+})
diff --git a/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.vue b/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.vue
index 306a6c137..e0f107d4a 100644
--- a/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.vue
+++ b/packages/stage-ui/src/components/scenarios/chat/components/sessions-drawer.vue
@@ -3,39 +3,20 @@ import type { ChatSessionMeta } from '../../../../types/chat-session'
 
 import { useResizeObserver, useScreenSafeArea } from '@vueuse/core'
 import { storeToRefs } from 'pinia'
-import { DialogContent, DialogOverlay, DialogPortal, DialogRoot, DialogTitle } from 'reka-ui'
-import { DrawerContent, DrawerHandle, DrawerOverlay, DrawerPortal, DrawerRoot, DrawerTitle } from 'vaul-vue'
 import { computed, onMounted, ref, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
 
+import SessionsDialog from './sessions-dialog.vue'
+
 import { useAnalytics } from '../../../../composables/use-analytics'
 import { useBreakpoints } from '../../../../composables/use-breakpoints'
 import { extractMessageText } from '../../../../libs/chat-sync'
 import { useAuthStore } from '../../../../stores/auth'
+import { useChatStore } from '../../../../stores/chat'
 import { useChatSessionStore } from '../../../../stores/chat/session-store'
 import { useAiriCardStore } from '../../../../stores/modules/airi-card'
 import { useConsciousnessStore } from '../../../../stores/modules/consciousness'
 
-/**
- * Bottom-sheet (mobile) / centered-modal (desktop) UI surface that lists every
- * chat session belonging to the current user, lets the user switch between
- * them, and start a fresh session for the active character.
- *
- * Use when:
- * - The user is on a stage page and wants to browse / switch conversations.
- *   Mounted once near the global ChatArea so any input bar can flip the
- *   `v-model` open.
- *
- * Expects:
- * - `useChatSessionStore` is initialized — `sessionMetas` and `activeSessionId`
- *   drive the list, and switching calls `setActiveSession` / `createSession`.
- *
- * Returns:
- * - A scrollable list. List items render the session title (or first user
- *   message preview as a fallback), a cloud-sync badge, and a relative
- *   updatedAt timestamp.
- */
-
 const showDialog = defineModel({ type: Boolean, default: false, required: false })
 
 const { isDesktop } = useBreakpoints()
@@ -43,18 +24,15 @@ const screenSafeArea = useScreenSafeArea()
 const { t } = useI18n()
 
 const chatSession = useChatSessionStore()
+const chat = useChatStore()
 const { sessionMetas, sessionMessages, activeSessionId } = storeToRefs(chatSession)
 const { activeCardId } = storeToRefs(useAiriCardStore())
 const { userId } = storeToRefs(useAuthStore())
 const { activeModel } = storeToRefs(useConsciousnessStore())
 const { trackChatSessionSelected, trackChatSessionStarted } = useAnalytics()
 
-// Re-entry guard for the "new session" button. Without this, a rapid
-// double-click would call `createSession` twice (creating two orphan
-// sessions) and emit duplicate `chat_session_started` analytics events.
-// The async `createSession` includes IndexedDB writes + a cloud reconcile
-// kick-off, so even a single click can stay in flight long enough for a
-// second click to slip through.
+// Creating includes persistence and cloud reconciliation, so prevent a
+// second click from creating an orphan session while the first is pending.
 const isCreatingSession = ref(false)
 
 useResizeObserver(document.documentElement, () => screenSafeArea.update())
@@ -67,30 +45,18 @@ interface SessionRow {
   updatedAtLabel: string
 }
 
-/**
- * Sessions visible in the drawer. Filters by the currently effective user
- * (`userId.value || 'local'`) so:
- * - Anonymous users see their local-only sessions (previously hidden by a
- *   blanket `userId !== 'local'` filter).
- * - After an account swap, the previously signed-in user's sessions stay
- *   hidden until ensureActiveSessionForCharacter rehydrates the new tenant
- *   (the session-store also clears in-memory state on user change as a
- *   defense in depth).
- */
+// Keep another account's sessions hidden while an account swap rehydrates.
 const ownedSessions = computed(() => {
   const effectiveUserId = userId.value || 'local'
   return Object.values(sessionMetas.value).filter(meta => meta.userId === effectiveUserId)
 })
 
 /**
- * Pull a 1-line preview from the first non-system message; falls back to the
- * stored title or a generic placeholder when nothing readable is available.
+ * Normalizes a session into its one-line drawer preview.
  *
- * Before:
- * - messages: [system, { role: 'user', content: 'Tell me about the moon today' }, ...]
- *
- * After:
- * - "Tell me about the moon today"
+ * @example
+ * previewFor({ title: 'Moon notes', ...meta })
+ * // => 'Moon notes'
  */
 function previewFor(meta: ChatSessionMeta): string {
   if (meta.title)
@@ -118,13 +84,11 @@ const RELATIVE_UNITS: Array<[Intl.RelativeTimeFormatUnit, number]> = [
 ]
 
 /**
- * Format an epoch ms timestamp as a coarse relative label like "3 minutes ago".
+ * Normalizes an epoch timestamp into a coarse relative label.
  *
- * Before:
- * - Date.now() - 5 * 60 * 1000
- *
- * After:
- * - "5 minutes ago"
+ * @example
+ * formatUpdatedAt(Date.now() - 5 * 60 * 1000)
+ * // => '5 minutes ago'
  */
 function formatUpdatedAt(ts: number): string {
   const formatter = new Intl.RelativeTimeFormat(undefined, { numeric: 'auto' })
@@ -147,12 +111,15 @@ const rows = computed<SessionRow[]>(() => {
       isActive: meta.sessionId === activeSessionId.value,
       updatedAtLabel: formatUpdatedAt(meta.updatedAt),
     }))
-  // Most-recent first; the active session usually ends up at the top after a
-  // fresh send because `persistSession` bumps `updatedAt`.
   list.sort((a, b) => b.meta.updatedAt - a.meta.updatedAt)
   return list
 })
 
+const mobilePaddingBottom = computed(() => {
+  const safeAreaBottom = Number.parseFloat(screenSafeArea.bottom.value.replace('px', ''))
+  return `${Math.max(safeAreaBottom, 24)}px`
+})
+
 async function selectSession(sessionId: string) {
   const selectedRow = rows.value.find(row => row.meta.sessionId === sessionId)
   if (sessionId !== activeSessionId.value && selectedRow) {
@@ -162,7 +129,7 @@ async function selectSession(sessionId: string) {
       cloud_synced: !!selectedRow.meta.cloudChatId,
     })
   }
-  chatSession.setActiveSession(sessionId)
+  await chatSession.setActiveSession(sessionId)
   showDialog.value = false
 }
 
@@ -172,12 +139,16 @@ async function startNewSession() {
   isCreatingSession.value = true
   try {
     const characterId = activeCardId.value || 'default'
-    await chatSession.createSession(characterId, { setActive: true })
-    // PostHog retention denominator. We pick this call site (UI new-session
-    // button) rather than `createSession` in the store because the store also
-    // creates sessions for cloud-reconcile / fork / restore flows that aren't
-    // user-initiated. Model id is informational; sessionIndex is omitted
-    // (PostHog can compute it from per-user event ordering).
+    const selectionBeforeCreation = activeSessionId.value
+    // Creation runs in the synchronized leader, while navigation belongs to
+    // this window. Activating inside createSession would navigate the leader.
+    const sessionId = await chatSession.createSession(characterId, { setActive: false })
+    // Rows remain interactive while creation is persisted in the leader. Do
+    // not let that stale continuation replace a newer local user selection.
+    if (activeSessionId.value === selectionBeforeCreation)
+      await chatSession.setActiveSession(sessionId)
+    // Store-created sessions also include restore and fork flows; only this
+    // user action belongs in the retention denominator.
     trackChatSessionStarted(activeModel.value || 'unknown')
     showDialog.value = false
   }
@@ -186,13 +157,6 @@ async function startNewSession() {
   }
 }
 
-async function deleteRow(event: Event, sessionId: string) {
-  // Stop the parent button's click — otherwise we'd switch into the session
-  // we are about to remove and immediately need a fallback.
-  event.stopPropagation()
-  await chatSession.deleteSession(sessionId)
-}
-
 // Per-open generation counter. The batch loadSession loop checks this before
 // each batch so closing the drawer mid-load aborts cleanly instead of
 // continuing to hydrate sessions the user has navigated away from. Without
@@ -200,17 +164,11 @@ async function deleteRow(event: Event, sessionId: string) {
 // re-added to `loadedSessions` as a phantom entry.
 let openGeneration = 0
 
-// Re-render relative timestamps + hydrate non-active session messages when
-// the drawer opens so each row can show a real preview instead of the
-// fallback. `loadSession` is idempotent (`loadedSessions` set), so reopening
-// the drawer is cheap.
 watch(showDialog, async (open) => {
   if (!open)
     return
   openGeneration += 1
   const myGeneration = openGeneration
-  // Touch `rows` first so reactive labels reflect a fresh `Date.now()`.
-  void rows.value
   const knownSessionIds = ownedSessions.value.map(meta => meta.sessionId)
   // Bounded concurrency keeps a long history list from spawning a hundred
   // simultaneous IndexedDB transactions; 4 in flight is plenty for a list
@@ -225,172 +183,18 @@ watch(showDialog, async (open) => {
 </script>
 
 <template>
-  <DialogRoot v-if="isDesktop" :open="showDialog" @update:open="value => showDialog = value">
-    <slot name="trigger" />
-    <DialogPortal>
-      <DialogOverlay
-        :class="[
-          'fixed inset-0 z-[9999] bg-black/50 backdrop-blur-sm',
-          'data-[state=closed]:animate-fadeOut data-[state=open]:animate-fadeIn',
-        ]"
-      />
-      <DialogContent
-        :class="[
-          'fixed left-1/2 top-1/2 z-[9999] max-h-[80dvh] max-w-md w-[92dvw] transform overflow-hidden rounded-2xl bg-white/95 shadow-xl outline-none backdrop-blur-md scrollbar-none -translate-x-1/2 -translate-y-1/2 data-[state=closed]:animate-contentHide data-[state=open]:animate-contentShow dark:bg-neutral-900/90',
-        ]"
-      >
-        <div :class="['flex flex-col h-full max-h-[80dvh]']">
-          <div :class="['flex items-center justify-between px-5 pt-5 pb-3']">
-            <DialogTitle :class="['text-base font-medium text-neutral-700 dark:text-neutral-200']">
-              {{ t('stage.chat.sessions.title') }}
-            </DialogTitle>
-            <button
-              :class="[
-                'rounded-lg px-3 py-1.5 text-xs font-medium',
-                'bg-primary-100/60 text-primary-700 dark:bg-primary-900/40 dark:text-primary-200',
-                'hover:bg-primary-200/70 dark:hover:bg-primary-800/50',
-                'transition-colors',
-              ]"
-              :disabled="isCreatingSession"
-              @click="startNewSession"
-            >
-              {{ t('stage.chat.sessions.new') }}
-            </button>
-          </div>
-          <div :class="['flex-1 overflow-y-auto px-2 pb-4']">
-            <div v-if="rows.length === 0" :class="['p-6 text-center text-sm text-neutral-500 dark:text-neutral-400']">
-              {{ t('stage.chat.sessions.empty') }}
-            </div>
-            <div
-              v-for="row in rows"
-              :key="row.meta.sessionId"
-              :class="[
-                'group relative w-full rounded-xl mb-1',
-                'transition-colors',
-                row.isActive
-                  ? 'bg-primary-100/70 dark:bg-primary-900/40'
-                  : 'hover:bg-neutral-100/80 dark:hover:bg-neutral-800/60',
-              ]"
-            >
-              <button
-                :class="['w-full text-left px-3 py-2.5 outline-none flex flex-col gap-1']"
-                @click="selectSession(row.meta.sessionId)"
-              >
-                <div :class="['flex items-center gap-2 text-sm font-medium text-neutral-700 dark:text-neutral-200']">
-                  <span :class="['truncate flex-1']">{{ row.preview }}</span>
-                  <span
-                    v-if="row.meta.cloudChatId"
-                    :class="['shrink-0 text-[10px] uppercase tracking-wide rounded px-1.5 py-0.5', 'bg-emerald-500/15 text-emerald-700 dark:text-emerald-300']"
-                    :title="t('stage.chat.sessions.cloud-badge')"
-                  >
-                    cloud
-                  </span>
-                  <!-- placeholder for trash icon to reserve hit space -->
-                  <span :class="['w-7']" />
-                </div>
-                <div :class="['text-[11px] text-neutral-500 dark:text-neutral-400']">
-                  {{ row.updatedAtLabel }}
-                </div>
-              </button>
-              <button
-                :class="[
-                  'absolute right-2 top-2 h-7 w-7 flex items-center justify-center rounded-md',
-                  'opacity-0 group-hover:opacity-100 focus:opacity-100',
-                  'text-neutral-400 hover:text-red-500 hover:bg-red-500/10',
-                  'transition-opacity duration-150',
-                ]"
-                :title="t('stage.chat.sessions.delete')"
-                @click="deleteRow($event, row.meta.sessionId)"
-              >
-                <div class="i-solar:trash-bin-trash-bold-duotone h-4 w-4" />
-              </button>
-            </div>
-          </div>
-        </div>
-      </DialogContent>
-    </DialogPortal>
-  </DialogRoot>
-  <DrawerRoot v-else :open="showDialog" should-scale-background @update:open="value => showDialog = value">
-    <DrawerPortal>
-      <DrawerOverlay :class="['fixed inset-0']" />
-      <DrawerContent
-        :class="[
-          'fixed bottom-0 left-0 right-0 z-1000',
-          'mt-20 px-2 pt-3',
-          'flex flex-col',
-          'h-full max-h-[85%]',
-          'rounded-t-[32px] outline-none backdrop-blur-md',
-          'bg-neutral-50/95 dark:bg-neutral-900/95',
-        ]"
-        :style="{ paddingBottom: `${Math.max(Number.parseFloat(screenSafeArea.bottom.value.replace('px', '')), 24)}px` }"
-      >
-        <DrawerHandle :class="['[div&]:bg-neutral-400 [div&]:dark:bg-neutral-600']" />
-        <div :class="['flex items-center justify-between px-4 pt-3 pb-2']">
-          <DrawerTitle :class="['text-base font-medium text-neutral-700 dark:text-neutral-200']">
-            {{ t('stage.chat.sessions.title') }}
-          </DrawerTitle>
-          <button
-            :class="[
-              'rounded-lg px-3 py-1.5 text-xs font-medium',
-              'bg-primary-100/60 text-primary-700 dark:bg-primary-900/40 dark:text-primary-200',
-              'hover:bg-primary-200/70 dark:hover:bg-primary-800/50',
-              'transition-colors',
-            ]"
-            :disabled="isCreatingSession"
-            @click="startNewSession"
-          >
-            {{ t('stage.chat.sessions.new') }}
-          </button>
-        </div>
-        <div :class="['flex-1 overflow-y-auto px-2 pb-2']">
-          <div v-if="rows.length === 0" :class="['p-6 text-center text-sm text-neutral-500 dark:text-neutral-400']">
-            {{ t('stage.chat.sessions.empty') }}
-          </div>
-          <div
-            v-for="row in rows"
-            :key="row.meta.sessionId"
-            :class="[
-              'group relative w-full rounded-xl mb-1',
-              'transition-colors',
-              row.isActive
-                ? 'bg-primary-100/70 dark:bg-primary-900/40'
-                : 'hover:bg-neutral-100/80 dark:hover:bg-neutral-800/60',
-            ]"
-          >
-            <button
-              :class="['w-full text-left px-3 py-3 outline-none flex flex-col gap-1']"
-              @click="selectSession(row.meta.sessionId)"
-            >
-              <div :class="['flex items-center gap-2 text-sm font-medium text-neutral-700 dark:text-neutral-200']">
-                <span :class="['truncate flex-1']">{{ row.preview }}</span>
-                <span
-                  v-if="row.meta.cloudChatId"
-                  :class="['shrink-0 text-[10px] uppercase tracking-wide rounded px-1.5 py-0.5', 'bg-emerald-500/15 text-emerald-700 dark:text-emerald-300']"
-                  :title="t('stage.chat.sessions.cloud-badge')"
-                >
-                  cloud
-                </span>
-                <span :class="['w-7']" />
-              </div>
-              <div :class="['text-[11px] text-neutral-500 dark:text-neutral-400']">
-                {{ row.updatedAtLabel }}
-              </div>
-            </button>
-            <button
-              :class="[
-                'absolute right-2 top-2 h-7 w-7 flex items-center justify-center rounded-md',
-                'opacity-100 md:opacity-0 md:group-hover:opacity-100 focus:opacity-100',
-                'text-neutral-400 hover:text-red-500 hover:bg-red-500/10',
-                'transition-opacity duration-150',
-              ]"
-              :title="t('stage.chat.sessions.delete')"
-              @click="deleteRow($event, row.meta.sessionId)"
-            >
-              <div class="i-solar:trash-bin-trash-bold-duotone h-4 w-4" />
-            </button>
-          </div>
-        </div>
-      </DrawerContent>
-    </DrawerPortal>
-  </DrawerRoot>
+  <SessionsDialog
+    v-model:open="showDialog"
+    :rows="rows"
+    :is-desktop="isDesktop"
+    :is-creating-session="isCreatingSession"
+    :mobile-padding-bottom="mobilePaddingBottom"
+    @new-session="startNewSession"
+    @select-session="selectSession"
+    @delete-session="chat.deleteSession"
+  >
+    <template #trigger>
+      <slot name="trigger" />
+    </template>
+  </SessionsDialog>
 </template>
diff --git a/packages/stage-ui/src/stores/character/orchestrator/index.test.ts b/packages/stage-ui/src/stores/character/orchestrator/index.test.ts
index b19d7c9ec..97b69a1a6 100644
--- a/packages/stage-ui/src/stores/character/orchestrator/index.test.ts
+++ b/packages/stage-ui/src/stores/character/orchestrator/index.test.ts
@@ -239,11 +239,13 @@ describe('store character-orchestrator', () => {
       forceTextResponse: true,
     })
 
-    const streamOptions = mockStream.mock.calls[0][3]
-    expect(streamOptions.supportsTools).toBe(false)
-    expect(streamOptions.waitForTools).toBe(false)
-    expect(streamOptions.tools).toEqual([])
-    expect(streamOptions.toolChoice).toBeUndefined()
+    const streamOptions = mockStream.mock.lastCall?.[3]
+    expect(streamOptions).toMatchObject({
+      supportsTools: false,
+      tools: [],
+      waitForTools: false,
+    })
+    expect(streamOptions?.toolChoice).toBeUndefined()
     expect(onDelta).toHaveBeenCalled()
     expect(onEnd).toHaveBeenCalled()
   })
@@ -290,12 +292,14 @@ describe('store character-orchestrator', () => {
       forceSparkCommandResponse: true,
     })
 
-    const streamOptions = mockStream.mock.calls[0][3]
-    expect(streamOptions.supportsTools).toBe(true)
-    expect(streamOptions.waitForTools).toBe(true)
-    expect(streamOptions.toolChoice).toEqual({
-      type: 'function',
-      function: { name: 'builtIn_sparkCommand' },
+    const streamOptions = mockStream.mock.lastCall?.[3]
+    expect(streamOptions).toMatchObject({
+      supportsTools: true,
+      toolChoice: {
+        type: 'function',
+        function: { name: 'builtIn_sparkCommand' },
+      },
+      waitForTools: true,
     })
     expect(result?.commands?.length).toBe(1)
     expect(sendSparkCommandMock).toHaveBeenCalledWith({
@@ -336,7 +340,7 @@ describe('store character-orchestrator', () => {
       },
     })
 
-    const renderedMessages = mockStream.mock.calls[0]?.[2] as Array<{ role: string, content: string }> | undefined
+    const renderedMessages = mockStream.mock.lastCall?.[2] as Array<{ role: string, content: string }> | undefined
     expect(String(renderedMessages?.[0]?.content)).toContain('Plugin-specific hint')
     expect(String(renderedMessages?.[1]?.content)).toContain('Rendered board snapshot')
   })
diff --git a/packages/stage-ui/src/stores/chat.contract.test.ts b/packages/stage-ui/src/stores/chat.contract.test.ts
index 772c20109..577036cb9 100644
--- a/packages/stage-ui/src/stores/chat.contract.test.ts
+++ b/packages/stage-ui/src/stores/chat.contract.test.ts
@@ -1,6 +1,7 @@
 import type { ChatProvider } from '@xsai-ext/providers/utils'
 import type { Message, Tool } from '@xsai/shared-chat'
 
+import { errorMessageFrom } from '@moeru/std'
 import { IOAttributes, IOSpanNames } from '@proj-airi/stage-shared'
 import { createPinia, setActivePinia } from 'pinia'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
@@ -71,6 +72,8 @@ const createMinecraftContextMock = vi.fn()
 const persistSessionMessagesMock = vi.fn()
 const forkSessionMock = vi.fn()
 const ensureSessionMock = vi.fn()
+const loadSessionMock = vi.fn()
+const deleteSessionMock = vi.fn()
 const getProviderInstanceMock = vi.fn()
 const getToolsByNamesMock = vi.fn<(names: string[]) => Tool[]>()
 
@@ -194,6 +197,9 @@ vi.mock('./chat/session-store', () => ({
       sessionMessages[sessionId] = []
     },
     getSessionMessages: (sessionId: string) => sessionMessages[sessionId] ?? [],
+    getSessionMessagesIfLoaded: (sessionId: string) => sessionMessages[sessionId],
+    loadSession: loadSessionMock,
+    deleteSession: deleteSessionMock,
     persistSessionMessages: persistSessionMessagesMock,
     getSessionGeneration: () => currentGeneration,
     setSessionMessages: (sessionId: string, messages: any[]) => {
@@ -285,6 +291,8 @@ describe('chat store contract', () => {
     persistSessionMessagesMock.mockReset()
     forkSessionMock.mockReset()
     ensureSessionMock.mockReset()
+    loadSessionMock.mockReset().mockResolvedValue(true)
+    deleteSessionMock.mockReset().mockResolvedValue(undefined)
     getProviderInstanceMock.mockReset().mockResolvedValue(provider)
     getToolsByNamesMock.mockReset().mockImplementation(names => names.map(name => ({
       type: 'function',
@@ -338,6 +346,51 @@ describe('chat store contract', () => {
     ])
   })
 
+  // https://github.com/moeru-ai/airi/issues/2085
+  it('hydrates the target session before sending for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // A synchronized follower could target a session known only by metadata.
+    // Reading through getSessionMessages before hydration created a fresh
+    // system-only history that could overwrite the persisted conversation.
+    delete sessionMessages['session-2']
+    loadSessionMock.mockImplementationOnce(async () => {
+      sessionMessages['session-2'] = [
+        { role: 'system', content: 'persisted system prompt', createdAt: 1, id: 'system-2' },
+      ]
+      return true
+    })
+    llmStreamMock.mockImplementationOnce(async (_model: string, _chatProvider: ChatProvider, _messages: Message[], options: any) => {
+      await options.onStreamEvent({ type: 'finish', finishReason: 'stop' })
+    })
+
+    const store = useChatStore()
+    await store.send({ sessionId: 'session-2', text: 'continue persisted chat' })
+
+    expect(loadSessionMock).toHaveBeenCalledWith('session-2')
+    expect(loadSessionMock.mock.invocationCallOrder[0]).toBeLessThan(ensureSessionMock.mock.invocationCallOrder[0])
+    expect(sessionMessages['session-2']?.[0]).toMatchObject({
+      content: 'persisted system prompt',
+      id: 'system-2',
+    })
+  })
+
+  // https://github.com/moeru-ai/airi/issues/2085
+  it('does not create fallback history when target hydration fails for Issue #2085', async () => {
+    delete sessionMessages['session-2']
+    loadSessionMock.mockResolvedValueOnce(false)
+
+    const store = useChatStore()
+    await expect(
+      store.send({ sessionId: 'session-2', text: 'do not overwrite history' }),
+    )
+      .rejects
+      .toThrow('Failed to load the target chat session')
+
+    expect(ensureSessionMock).not.toHaveBeenCalledWith('session-2')
+    expect(sessionMessages['session-2']).toBeUndefined()
+  })
+
   it('forwards one correlation identity across every PostHog chat milestone', async () => {
     llmStreamMock.mockImplementation(async (_model: string, _chatProvider: ChatProvider, _messages: Message[], options: any) => {
       await options.onStreamEvent({ type: 'text-delta', text: 'ok' })
@@ -650,30 +703,31 @@ describe('chat store contract', () => {
     expect(specialHook.mock.calls[0]?.[1].turnId.length).toBeGreaterThan(0)
   })
 
-  /**
-   * @example
-   * store.sending = true
-   * await nextTick()
-   * expect(store.sending).toBe(true)
-   */
-  it('keeps sending writable for context bridge and chat sync consumers', async () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743261505
+  it('preserves a synchronized sending snapshot without replaying it through the follower runtime for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Applying `sending: true` invoked the follower's idle runtime, whose
+    // derived state cleared the synchronized stream payload and could target
+    // that follower's unrelated local selection.
     const store = useChatStore()
-
-    expect(store.sending).toBe(false)
-
-    store.sending = true
+    store.$patch({
+      sending: true,
+      activeSendSessionId: 'session-b',
+      activeStreamingMessage: {
+        role: 'assistant',
+        content: 'authority stream',
+        slices: [],
+        tool_results: [],
+      },
+    })
     await nextTick()
+
     expect(store.sending).toBe(true)
-
-    store.sending = false
-    await nextTick()
-    expect(store.sending).toBe(false)
+    expect(store.activeSendSessionId).toBe('session-b')
+    expect(store.activeStreamingMessage?.content).toBe('authority stream')
   })
 
-  /**
-   * @example
-   * store.sending = false while a local runtime send is still streaming.
-   */
   it('does not end the owned IO turn span when external sending mirror is cleared mid-send', async () => {
     let releaseStream: (() => void) | undefined
     llmStreamMock.mockImplementationOnce(async () => {
@@ -711,11 +765,6 @@ describe('chat store contract', () => {
     expect(ioTracerMocks.activeTurnSpan.value).toBeUndefined()
   })
 
-  /**
-   * @example
-   * createMinecraftContext() returns a runtime context update.
-   * The facade passes it into the core runtime before prompt snapshots are read.
-   */
   it('ingests runtime context providers before composing prompt snapshots', async () => {
     const minecraftContext = {
       id: 'minecraft-context',
@@ -788,11 +837,60 @@ describe('chat store contract', () => {
     await firstSend
   })
 
-  /**
-   * @example
-   * store.getPendingQueuedSendSnapshot()
-   * // => [{ sessionId, generation, cancelled, messagePreview, hasAttachments, inputType }]
-   */
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3742939573
+  it('does not recreate a deleted session when queued work is cancelled for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Cancelling queued work rejects the public send action. Its generic error
+    // handler used to recreate a system-plus-error history after deletion,
+    // leaving a ghost conversation that no longer had session metadata.
+    let releaseFirstSend: (() => void) | undefined
+    llmStreamMock.mockImplementationOnce(async () => {
+      await new Promise<void>((resolve) => {
+        releaseFirstSend = resolve
+      })
+    })
+    deleteSessionMock.mockImplementationOnce(async () => {
+      currentGeneration += 1
+      delete sessionMessages['session-1']
+    })
+
+    const store = useChatStore()
+    const firstSend = store.send({
+      sessionId: 'session-1',
+      text: 'active turn',
+    })
+    const activeOutcome = firstSend.then(
+      () => 'resolved',
+      error => errorMessageFrom(error) ?? 'unknown error',
+    )
+    const queuedSend = store.send({
+      sessionId: 'session-1',
+      text: 'must be cancelled',
+    })
+    const queuedOutcome = queuedSend.then(
+      () => 'resolved',
+      error => errorMessageFrom(error) ?? 'unknown error',
+    )
+
+    await vi.waitFor(() => {
+      expect(llmStreamMock).toHaveBeenCalledTimes(1)
+    })
+    await vi.waitFor(() => {
+      expect(store.pendingQueuedSendCount).toBe(1)
+    })
+    await store.deleteSession('session-1')
+
+    expect(deleteSessionMock).toHaveBeenCalledWith('session-1')
+    expect(await queuedOutcome).toBe('Chat session was reset before send could start')
+    expect(sessionMessages['session-1']).toBeUndefined()
+
+    releaseFirstSend?.()
+    expect(await activeOutcome).toBe('Chat session was removed before send completed')
+    expect(llmStreamMock).toHaveBeenCalledTimes(1)
+    expect(sessionMessages['session-1']).toBeUndefined()
+  })
+
   it('mirrors pending queued send snapshots from the core runtime', async () => {
     let releaseFirstSend: (() => void) | undefined
     llmStreamMock.mockImplementationOnce(async () => {
diff --git a/packages/stage-ui/src/stores/chat.ts b/packages/stage-ui/src/stores/chat.ts
index 2dc8a9b52..be592540b 100644
--- a/packages/stage-ui/src/stores/chat.ts
+++ b/packages/stage-ui/src/stores/chat.ts
@@ -4,7 +4,7 @@ import type { ChatProvider } from '@xsai-ext/providers/utils'
 import type { Message } from '@xsai/shared-chat'
 import type {} from 'pinia-plugin-synced'
 
-import type { ChatHistoryItem, ChatToolReference } from '../types/chat'
+import type { ChatHistoryItem, ChatToolReference, StreamingAssistantMessage } from '../types/chat'
 import type { ToolCallRerunPayload } from './tool-call-rerun'
 
 import { errorMessageFrom } from '@moeru/std'
@@ -12,7 +12,7 @@ import { createChatOrchestratorRuntime } from '@proj-airi/core-agent'
 import { IOAttributes, IOEvents, IOSpanNames, IOSubsystems } from '@proj-airi/stage-shared'
 import { nanoid } from 'nanoid'
 import { defineStore, storeToRefs } from 'pinia'
-import { ref, toRaw, watch } from 'vue'
+import { shallowRef, toRaw } from 'vue'
 
 import { getConversationAnalyticsSurface } from '../composables'
 import { activeTurnSpan, startSpan } from '../composables/use-io-tracer'
@@ -157,8 +157,10 @@ export const useChatStore = defineStore('chat', () => {
   const { activeSessionId } = storeToRefs(chatSession)
   const { streamingMessage } = storeToRefs(chatStream)
 
-  const sending = ref(false)
-  const pendingQueuedSendCount = ref(0)
+  const sending = shallowRef(false)
+  const activeSendSessionId = shallowRef<string>()
+  const activeStreamingMessage = shallowRef<StreamingAssistantMessage>()
+  const pendingQueuedSendCount = shallowRef(0)
   let ownedActiveTurnSpan: typeof activeTurnSpan.value
   const analyticsHooks = createChatAnalyticsHooks({
     getSessionMessages: sessionId => chatSession.getSessionMessages(sessionId),
@@ -229,6 +231,8 @@ export const useChatStore = defineStore('chat', () => {
 
   function syncRuntimeState(state: ChatOrchestratorRuntimeState) {
     sending.value = state.sending
+    activeSendSessionId.value = state.activeSendSessionId
+    activeStreamingMessage.value = state.activeStreamingMessage
     pendingQueuedSendCount.value = state.pendingQueuedSendCount
   }
 
@@ -317,11 +321,6 @@ export const useChatStore = defineStore('chat', () => {
     },
   })
 
-  watch(sending, (next) => {
-    if (runtime.getSending() !== next)
-      runtime.setSending(next)
-  })
-
   async function ingest(
     sendingMessage: string,
     options: ChatOrchestratorSendOptions,
@@ -345,6 +344,9 @@ export const useChatStore = defineStore('chat', () => {
   }
 
   function appendSendError(sessionId: string, error: unknown) {
+    if (!chatSession.getSessionMessagesIfLoaded(sessionId))
+      return
+
     chatSession.appendSessionMessage(sessionId, {
       role: 'error',
       content: errorMessageFrom(error) ?? 'Unknown chat operation failure',
@@ -357,6 +359,9 @@ export const useChatStore = defineStore('chat', () => {
     if (!providerId || !modelId)
       throw new Error('No active chat provider or model configured')
 
+    if (!await chatSession.loadSession(payload.sessionId))
+      throw new Error('Failed to load the target chat session')
+
     const messageCount = chatSession.getSessionMessages(payload.sessionId).length
     const chatProvider = await providerStore.getProviderInstance<ChatProvider>(providerId)
     if (!chatProvider)
@@ -376,8 +381,12 @@ export const useChatStore = defineStore('chat', () => {
       },
     }, payload.sessionId)
 
+    const completedMessages = chatSession.getSessionMessagesIfLoaded(payload.sessionId)
+    if (!completedMessages)
+      throw new Error('Chat session was removed before send completed')
+
     return {
-      messages: chatSession.getSessionMessages(payload.sessionId)
+      messages: completedMessages
         .slice(messageCount)
         .map(message => structuredClone(toRaw(message))),
       sessionId: payload.sessionId,
@@ -397,6 +406,9 @@ export const useChatStore = defineStore('chat', () => {
 
   /** Replaces one stored turn with a new execution of its user message. */
   async function retry(payload: ChatRetryPayload): Promise<ChatSendResult> {
+    if (!await chatSession.loadSession(payload.sessionId))
+      throw new Error('Failed to load the target chat session')
+
     const currentMessages = chatSession.getSessionMessages(payload.sessionId)
     const sourceIndex = retrySourceIndexFrom(currentMessages, payload.index)
     if (sourceIndex < 0)
@@ -424,6 +436,9 @@ export const useChatStore = defineStore('chat', () => {
 
   /** Runs one stored tool call again and replaces its stored result. */
   async function rerunToolCall(payload: ChatToolCallRerunPayload): Promise<void> {
+    if (!await chatSession.loadSession(payload.sessionId))
+      throw new Error('Failed to load the target chat session')
+
     const nextMessages = await executeToolCallRerun({
       messages: chatSession.getSessionMessages(payload.sessionId),
       payload,
@@ -442,6 +457,12 @@ export const useChatStore = defineStore('chat', () => {
     chatStream.resetStream()
   }
 
+  /** Cancels queued work before permanently removing its owning session. */
+  function deleteSession(sessionId: string): Promise<void> {
+    runtime.cancelPendingSends(sessionId)
+    return chatSession.deleteSession(sessionId)
+  }
+
   async function ingestOnFork(
     sendingMessage: string,
     options: ChatOrchestratorSendOptions,
@@ -470,9 +491,12 @@ export const useChatStore = defineStore('chat', () => {
 
   return {
     sending,
+    activeSendSessionId,
+    activeStreamingMessage,
     pendingQueuedSendCount,
 
     cleanup,
+    deleteSession,
     ingest,
     ingestOnFork,
     rerunToolCall,
@@ -507,7 +531,7 @@ export const useChatStore = defineStore('chat', () => {
   }
 }, {
   synced: {
-    actions: ['cleanup', 'rerunToolCall', 'retry', 'send'],
+    actions: ['cleanup', 'deleteSession', 'rerunToolCall', 'retry', 'send'],
     state: true,
   },
 })
diff --git a/packages/stage-ui/src/stores/chat/session-store.test.ts b/packages/stage-ui/src/stores/chat/session-store.test.ts
index c1600d774..c2e0a735d 100644
--- a/packages/stage-ui/src/stores/chat/session-store.test.ts
+++ b/packages/stage-ui/src/stores/chat/session-store.test.ts
@@ -1,7 +1,7 @@
 import type { ChatSessionMeta, ChatSessionRecord, ChatSessionsIndex } from '../../types/chat-session'
 
-import { createPinia, setActivePinia } from 'pinia'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { createPinia, disposePinia, setActivePinia } from 'pinia'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { nextTick, ref } from 'vue'
 
 // Refs the store reads through the mocked `useAuthStore` / `useAiriCardStore`.
@@ -19,6 +19,14 @@ const getOutboxMock = vi.fn<(uid: string) => Promise<any[]>>()
 const dropOutboxForSessionMock = vi.fn<(uid: string, id: string) => Promise<void>>()
 const getTombstonesMock = vi.fn<(uid: string) => Promise<string[]>>()
 const removeTombstonesMock = vi.fn<(uid: string, ids: string[]) => Promise<void>>()
+const addTombstoneMock = vi.fn<(uid: string, id: string) => Promise<void>>()
+const deleteCloudChatMock = vi.fn<(id: string) => Promise<void>>()
+const listChatsMock = vi.fn()
+const pullMessagesMock = vi.fn()
+const reconcileLocalAndRemoteMock = vi.fn()
+const connectCloudWsMock = vi.fn()
+let cloudWsStatus: 'idle' | 'open' = 'idle'
+let cloudStatusListener: ((status: 'idle' | 'open') => void) | undefined
 
 vi.mock('pinia', async () => {
   const actual = await vi.importActual<typeof import('pinia')>('pinia')
@@ -52,7 +60,7 @@ vi.mock('../../database/repos/chat-sessions.repo', () => ({
     updateOutboxEntries: vi.fn().mockResolvedValue(undefined),
     dropOutboxForSession: (uid: string, id: string) => dropOutboxForSessionMock(uid, id),
     getTombstones: (uid: string) => getTombstonesMock(uid),
-    addTombstone: vi.fn().mockResolvedValue(undefined),
+    addTombstone: (uid: string, id: string) => addTombstoneMock(uid, id),
     removeTombstones: (uid: string, ids: string[]) => removeTombstonesMock(uid, ids),
   },
 }))
@@ -74,20 +82,23 @@ vi.mock('../../libs/server', () => ({
 // sufficient. We keep `extractMessageText` realistic so message previews work.
 vi.mock('../../libs/chat-sync', () => ({
   applyCreateActions: vi.fn().mockResolvedValue([]),
-  reconcileLocalAndRemote: vi.fn().mockReturnValue({ adopt: [], claim: [], create: [] }),
+  reconcileLocalAndRemote: (...args: unknown[]) => reconcileLocalAndRemoteMock(...args),
   createCloudChatMapper: () => ({
-    listChats: vi.fn().mockResolvedValue([]),
-    deleteChat: vi.fn().mockResolvedValue(undefined),
+    listChats: () => listChatsMock(),
+    deleteChat: (id: string) => deleteCloudChatMock(id),
   }),
   createChatWsClient: () => ({
-    status: () => 'idle' as const,
-    connect: vi.fn(),
+    status: () => cloudWsStatus,
+    connect: connectCloudWsMock,
     disconnect: vi.fn(),
     destroy: vi.fn(),
     sendMessages: vi.fn().mockResolvedValue({ ok: true }),
-    pullMessages: vi.fn().mockResolvedValue({ messages: [], maxSeq: 0 }),
+    pullMessages: (...args: unknown[]) => pullMessagesMock(...args),
     onNewMessages: () => () => {},
-    onStatusChange: () => () => {},
+    onStatusChange: (listener: (status: 'idle' | 'open') => void) => {
+      cloudStatusListener = listener
+      return () => {}
+    },
   }),
   extractMessageText: (m: any) => (typeof m?.content === 'string' ? m.content : ''),
   isCloudSyncableMessage: () => false,
@@ -95,9 +106,11 @@ vi.mock('../../libs/chat-sync', () => ({
 }))
 
 const { useChatSessionStore } = await import('./session-store')
+let pinia: ReturnType<typeof createPinia>
 
 beforeEach(() => {
-  setActivePinia(createPinia())
+  pinia = createPinia()
+  setActivePinia(pinia)
   userIdRef.value = 'local'
   activeCardIdRef.value = 'default'
   systemPromptRef.value = ''
@@ -111,6 +124,18 @@ beforeEach(() => {
   dropOutboxForSessionMock.mockReset().mockResolvedValue(undefined)
   getTombstonesMock.mockReset().mockResolvedValue([])
   removeTombstonesMock.mockReset().mockResolvedValue(undefined)
+  addTombstoneMock.mockReset().mockResolvedValue(undefined)
+  deleteCloudChatMock.mockReset().mockResolvedValue(undefined)
+  listChatsMock.mockReset().mockResolvedValue([])
+  pullMessagesMock.mockReset().mockResolvedValue({ messages: [], seq: 0 })
+  reconcileLocalAndRemoteMock.mockReset().mockReturnValue({ adopt: [], claim: [], create: [] })
+  connectCloudWsMock.mockReset()
+  cloudWsStatus = 'idle'
+  cloudStatusListener = undefined
+})
+
+afterEach(() => {
+  disposePinia(pinia)
 })
 
 async function flushMicrotasks(rounds = 8) {
@@ -295,6 +320,291 @@ describe('chat-session-store · loadSession vs concurrent deleteSession', () =>
   })
 })
 
+describe('chat-session-store · deletion and hydration failures', () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743502031
+  it('persists the fallback without changing the leader selection when a follower deletes its active session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Session selection is window-local, so the synchronized leader can be on
+    // A while the persisted index still points to B. Deleting B returned A but
+    // left the persisted index empty, so the next startup created a blank chat.
+    const sessionA: ChatSessionMeta = {
+      sessionId: 'session-a',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const sessionB: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 2,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-a',
+      sessionMessages: { 'session-a': [], 'session-b': [] },
+      sessionMetas: { 'session-a': sessionA, 'session-b': sessionB },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-b',
+            sessions: { 'session-a': sessionA, 'session-b': sessionB },
+          },
+        },
+      },
+    })
+
+    await store.deleteSession('session-b')
+
+    expect(store.activeSessionId).toBe('session-a')
+    expect(store.getSnapshot().index?.characters.default?.activeSessionId).toBe('session-a')
+    expect(store.sessionMetas['session-b']).toBeUndefined()
+    expect(saveIndexMock).toHaveBeenLastCalledWith(expect.objectContaining({
+      characters: expect.objectContaining({
+        default: expect.objectContaining({ activeSessionId: 'session-a' }),
+      }),
+    }))
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743309237
+  it('persists a replacement fallback without changing an unrelated leader selection for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // When a follower deleted the final session for one character, the leader
+    // created a replacement with local activation disabled. The replacement
+    // was indexed but the persisted character active ID stayed empty, so the
+    // next initialization created another blank conversation.
+    const leaderSession: ChatSessionMeta = {
+      sessionId: 'leader-session',
+      userId: 'local',
+      characterId: 'other-character',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const deletedSession: ChatSessionMeta = {
+      sessionId: 'deleted-session',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 2,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'leader-session',
+      sessionMessages: { 'leader-session': [], 'deleted-session': [] },
+      sessionMetas: { 'leader-session': leaderSession, 'deleted-session': deletedSession },
+      index: {
+        userId: 'local',
+        characters: {
+          'other-character': {
+            activeSessionId: 'leader-session',
+            sessions: { 'leader-session': leaderSession },
+          },
+          'default': {
+            activeSessionId: 'deleted-session',
+            sessions: { 'deleted-session': deletedSession },
+          },
+        },
+      },
+    })
+
+    await store.deleteSession('deleted-session')
+    const snapshot = store.getSnapshot()
+    const [replacementSessionId] = Object.keys(snapshot.index?.characters.default?.sessions ?? {})
+    expect(replacementSessionId).toBeDefined()
+    if (!replacementSessionId)
+      throw new Error('Expected deletion to create a replacement session')
+
+    expect(store.activeSessionId).toBe('leader-session')
+    expect(snapshot.index?.characters.default?.activeSessionId).toBe(replacementSessionId)
+    expect(snapshot.index?.characters.default?.sessions[replacementSessionId]).toBeDefined()
+    expect(saveIndexMock).toHaveBeenLastCalledWith(expect.objectContaining({
+      characters: expect.objectContaining({
+        default: expect.objectContaining({ activeSessionId: replacementSessionId }),
+      }),
+    }))
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3628917803
+  it('keeps deleted session generations invalid for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Deletion previously removed the generation entry. A send captured at
+    // generation zero could then read the deleted session as generation zero
+    // again and continue appending messages after the chat was gone.
+    const meta: ChatSessionMeta = {
+      sessionId: 'sess-1',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'sess-1',
+      sessionMessages: { 'sess-1': [] },
+      sessionMetas: { 'sess-1': meta },
+      index: null,
+    })
+
+    expect(store.getSessionGeneration('sess-1')).toBe(0)
+
+    await store.deleteSession('sess-1')
+
+    expect(store.getSessionGeneration('sess-1')).toBe(1)
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3628003766
+  it('reports hydration failure and permits a later retry for Issue #2085', async () => {
+    const meta: ChatSessionMeta = {
+      sessionId: 'sess-1',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+    getSessionMock
+      .mockRejectedValueOnce(new Error('IndexedDB read failed'))
+      .mockResolvedValueOnce(null)
+
+    userIdRef.value = 'local'
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: '',
+      sessionMessages: {},
+      sessionMetas: { 'sess-1': meta },
+      index: null,
+    })
+
+    await expect(store.loadSession('sess-1')).resolves.toBe(false)
+    await expect(store.loadSession('sess-1')).resolves.toBe(true)
+
+    expect(getSessionMock).toHaveBeenCalledTimes(2)
+  })
+})
+
+describe('chat-session-store · cloud placeholder hydration', () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743502032
+  it('retries cloud hydration when the reconcile pull for an adopted placeholder fails for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Reconcile creates a system-only placeholder before its first cloud pull.
+    // If that pull fails, loadSession sees the message-map entry and marks the
+    // placeholder as loaded. Selecting the chat then skips every later pull.
+    const localMeta: ChatSessionMeta = {
+      sessionId: 'local-session',
+      userId: 'cloud-user',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const remoteChat = {
+      id: 'remote-session',
+      type: 'bot' as const,
+      title: null,
+      createdAt: '2026-01-01T00:00:00.000Z',
+      updatedAt: '2026-01-01T00:00:00.000Z',
+    }
+    userIdRef.value = 'cloud-user'
+    getIndexMock.mockResolvedValue({
+      userId: 'cloud-user',
+      characters: {
+        default: {
+          activeSessionId: localMeta.sessionId,
+          sessions: { [localMeta.sessionId]: localMeta },
+        },
+      },
+    })
+    getSessionMock.mockImplementation((sessionId) => {
+      if (sessionId === remoteChat.id) {
+        return Promise.resolve({
+          meta: {
+            sessionId: remoteChat.id,
+            userId: 'cloud-user',
+            characterId: 'default',
+            createdAt: Date.parse(remoteChat.createdAt),
+            updatedAt: Date.parse(remoteChat.updatedAt),
+            cloudChatId: remoteChat.id,
+          },
+          messages: [],
+        })
+      }
+      return Promise.resolve({ meta: localMeta, messages: [] })
+    })
+    listChatsMock.mockResolvedValue([remoteChat])
+    reconcileLocalAndRemoteMock.mockReturnValue({ adopt: [remoteChat], claim: [], create: [] })
+    pullMessagesMock
+      .mockRejectedValueOnce(new Error('temporary cloud failure'))
+      .mockResolvedValueOnce({ messages: [], seq: 0 })
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+    const store = useChatSessionStore()
+    await store.initialize()
+    expect(cloudStatusListener).toBeDefined()
+
+    cloudWsStatus = 'open'
+    cloudStatusListener?.('open')
+    await vi.waitFor(() => {
+      expect(store.cloudSyncReady).toBe(true)
+    })
+    expect(pullMessagesMock).toHaveBeenCalledTimes(1)
+
+    await store.setActiveSession(remoteChat.id)
+
+    expect(pullMessagesMock).toHaveBeenCalledTimes(2)
+  })
+})
+
+describe('chat-session-store · cloud deletion', () => {
+  it('tombstones an unmapped cloud session before an in-flight create can finish', async () => {
+    // ROOT CAUSE:
+    //
+    // A newly created cloud session can be deleted before POST /chats binds
+    // its cloud id. Without a tombstone for the deterministic session id, the
+    // completed remote create is adopted again by the next reconcile.
+    userIdRef.value = 'cloud-user'
+    const deleted: ChatSessionMeta = {
+      sessionId: 'pending-cloud-session',
+      userId: 'cloud-user',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const survivor: ChatSessionMeta = {
+      sessionId: 'surviving-session',
+      userId: 'cloud-user',
+      characterId: 'default',
+      createdAt: 2,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'surviving-session',
+      sessionMessages: { 'pending-cloud-session': [], 'surviving-session': [] },
+      sessionMetas: { 'pending-cloud-session': deleted, 'surviving-session': survivor },
+      index: {
+        userId: 'cloud-user',
+        characters: {
+          default: {
+            activeSessionId: 'pending-cloud-session',
+            sessions: { 'pending-cloud-session': deleted, 'surviving-session': survivor },
+          },
+        },
+      },
+    })
+
+    await store.deleteSession('pending-cloud-session')
+
+    expect(addTombstoneMock).toHaveBeenCalledWith('cloud-user', 'pending-cloud-session')
+    expect(deleteCloudChatMock).not.toHaveBeenCalled()
+  })
+})
+
 describe('chat-session-store · active card prompt edits', () => {
   // ROOT CAUSE:
   //
@@ -394,6 +704,257 @@ describe('chat-session-store · active card prompt edits', () => {
 })
 
 describe('chat-session-store · synchronized data actions', () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3755711151
+  it('keeps cloud synchronization in the elected leader for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Window-local initialization opened a cloud WebSocket in every window.
+    // Follower callbacks then proposed direct full-state mutations.
+    const store = useChatSessionStore()
+    store.setCloudSyncOwnership(false)
+    await store.initialize()
+
+    userIdRef.value = 'cloud-user'
+    await nextTick()
+    expect(connectCloudWsMock).not.toHaveBeenCalled()
+
+    store.setCloudSyncOwnership(true)
+    expect(connectCloudWsMock).toHaveBeenCalledTimes(1)
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743242525
+  it('initializes a new window selection from the synchronized index for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // `ready` was synchronized while selection was not. A joining window saw
+    // the leader's ready flag, skipped initialization, and remained on an
+    // empty local selection.
+    const session: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const store = useChatSessionStore()
+    store.$patch({
+      sessionMessages: { 'session-b': [{ id: 'system', role: 'system', content: 'prompt' }] },
+      sessionMetas: { 'session-b': session },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-b',
+            sessions: { 'session-b': session },
+          },
+        },
+      },
+    })
+
+    expect(store.$state).not.toHaveProperty('ready')
+    expect(store.activeSessionId).toBe('')
+
+    await store.initialize()
+
+    expect(store.activeSessionId).toBe('session-b')
+    expect(store.isReady).toBe(true)
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743242529
+  it('trusts synchronized messages instead of merging a stale follower IDB record for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Follower hydration read its own older IndexedDB record and mutated the
+    // fully synchronized store, allowing that stale snapshot to overwrite the
+    // leader's newer messages or resurrect a deleted session.
+    const session: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 2,
+    }
+    getSessionMock.mockResolvedValue({
+      meta: { ...session, updatedAt: 1 },
+      messages: [{ id: 'stale', role: 'user', content: 'stale follower data' }],
+    })
+    const store = useChatSessionStore()
+    store.$patch({
+      sessionMessages: {
+        'session-b': [{ id: 'current', role: 'assistant', content: 'leader data', slices: [], tool_results: [] }],
+      },
+      sessionMetas: { 'session-b': session },
+    })
+
+    await expect(store.loadSession('session-b')).resolves.toBe(true)
+
+    expect(getSessionMock).not.toHaveBeenCalled()
+    expect(store.getSessionMessagesIfLoaded('session-b')?.map(message => message.id)).toEqual(['current'])
+  })
+
+  it('refreshes an already loaded session from IndexedDB for a completed remote stream', async () => {
+    const session: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: { 'session-b': [{ id: 'system', role: 'system', content: 'prompt' }] },
+      sessionMetas: { 'session-b': session },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-b',
+            sessions: { 'session-b': session },
+          },
+        },
+      },
+    })
+    getSessionMock.mockResolvedValue({
+      meta: session,
+      messages: [
+        { id: 'system', role: 'system', content: 'prompt' },
+        { id: 'assistant', role: 'assistant', content: 'complete answer', slices: [], tool_results: [] },
+      ],
+    })
+
+    await expect(store.refreshSession('session-b')).resolves.toBe(true)
+
+    expect(getSessionMock).toHaveBeenCalledWith('session-b')
+    expect(store.getSessionMessages('session-b').map(message => message.id)).toEqual(['system', 'assistant'])
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743121862
+  it('moves a follower away from a session removed by another window for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Synchronized deletion removed B's metadata, but activeSessionId is
+    // intentionally window-local. A follower that also selected B therefore
+    // kept an invalid selection until it manually chose another session.
+    const sessionA: ChatSessionMeta = {
+      sessionId: 'session-a',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const sessionB: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 2,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: { 'session-a': [], 'session-b': [] },
+      sessionMetas: { 'session-a': sessionA, 'session-b': sessionB },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-a',
+            sessions: { 'session-a': sessionA, 'session-b': sessionB },
+          },
+        },
+      },
+    })
+    await nextTick()
+
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: { 'session-a': [] },
+      sessionMetas: { 'session-a': sessionA },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-a',
+            sessions: { 'session-a': sessionA },
+          },
+        },
+      },
+    })
+    await nextTick()
+
+    expect(store.activeSessionId).toBe('session-a')
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743221033
+  it('waits for the leader replacement when every window loses its last session for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Every follower independently created a replacement when synchronized
+    // deletion temporarily left no metadata. Multiple windows could therefore
+    // turn one deletion into several empty chats before state converged.
+    const removedSession: ChatSessionMeta = {
+      sessionId: 'session-b',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 1,
+      updatedAt: 1,
+    }
+    const replacementSession: ChatSessionMeta = {
+      sessionId: 'session-c',
+      userId: 'local',
+      characterId: 'default',
+      createdAt: 2,
+      updatedAt: 2,
+    }
+    const store = useChatSessionStore()
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: { 'session-b': [] },
+      sessionMetas: { 'session-b': removedSession },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-b',
+            sessions: { 'session-b': removedSession },
+          },
+        },
+      },
+    })
+    await nextTick()
+    saveSessionMock.mockClear()
+
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: {},
+      sessionMetas: {},
+      index: { userId: 'local', characters: {} },
+    })
+    await nextTick()
+
+    expect(saveSessionMock).not.toHaveBeenCalled()
+    expect(store.activeSessionId).toBe('session-b')
+
+    store.applyRemoteSnapshot({
+      activeSessionId: 'session-b',
+      sessionMessages: { 'session-c': [] },
+      sessionMetas: { 'session-c': replacementSession },
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'session-c',
+            sessions: { 'session-c': replacementSession },
+          },
+        },
+      },
+    })
+    await nextTick()
+
+    expect(store.activeSessionId).toBe('session-c')
+  })
+
   it('deletes a message by its stable id from the specified session', async () => {
     const store = useChatSessionStore()
     store.applyRemoteSnapshot({
@@ -415,11 +976,29 @@ describe('chat-session-store · synchronized data actions', () => {
     expect(store.getSessionMessages('session-1').map(message => message.id)).toEqual(['keep'])
   })
 
-  it('keeps the active session outside synchronized session state', () => {
+  it('keeps window-local selection out of synchronized and persisted session state', async () => {
     const store = useChatSessionStore()
-    store.activeSessionId = 'window-local-session'
+    store.applyRemoteSnapshot({
+      activeSessionId: 'persisted-session',
+      index: {
+        userId: 'local',
+        characters: {
+          default: {
+            activeSessionId: 'persisted-session',
+            sessions: {},
+          },
+        },
+      },
+      sessionMessages: {
+        'window-local-session': [{ id: 'system', role: 'system', content: 'prompt' }],
+      },
+      sessionMetas: {},
+    })
+
+    await store.setActiveSession('window-local-session')
 
     expect(store.activeSessionId).toBe('window-local-session')
     expect(store.$state).not.toHaveProperty('activeSessionId')
+    expect(store.getSnapshot().index?.characters.default?.activeSessionId).toBe('persisted-session')
   })
 })
diff --git a/packages/stage-ui/src/stores/chat/session-store.ts b/packages/stage-ui/src/stores/chat/session-store.ts
index 794fb8f3c..3eef6682c 100644
--- a/packages/stage-ui/src/stores/chat/session-store.ts
+++ b/packages/stage-ui/src/stores/chat/session-store.ts
@@ -76,6 +76,7 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   const sessionMessages = ref<Record<string, ChatHistoryItem[]>>({})
   const sessionMetas = ref<Record<string, ChatSessionMeta>>({})
   const sessionGenerations = ref<Record<string, number>>({})
+  /** Authority-owned session index replicated so each window can derive its local selection. */
   const index = ref<ChatSessionsIndex | null>(null)
 
   const ready = ref(false)
@@ -92,7 +93,9 @@ export const useChatSessionStore = defineStore('chat-session', () => {
 
   let persistQueue = Promise.resolve()
   const loadedSessions = new Set<string>()
-  const loadingSessions = new Map<string, Promise<void>>()
+  const staleSessions = new Set<string>()
+  const cloudHydratedSessions = new Set<string>()
+  const loadingSessions = new Map<string, Promise<boolean>>()
 
   // Cloud sync state. The WS client is constructed lazily so anonymous
   // (`userId === 'local'`) users never open a socket. `cloudSyncReady` is a
@@ -110,6 +113,7 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   let cloudMapper: CloudChatMapper | undefined
   let cloudReconcileTask: Promise<void> | undefined
   let pendingReconcile = false
+  let ownsCloudSync = true
   // Incremented on every teardown / user swap. Long-running reconcile IIFEs
   // capture the epoch at start and bail after every await once it changes,
   // so account-A mutations cannot land on account-B state after a sign-out.
@@ -327,7 +331,10 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   }
 
   /** Removes one message by stable id or by its current history index. */
-  function deleteMessage(payload: DeleteChatMessagePayload) {
+  async function deleteMessage(payload: DeleteChatMessagePayload): Promise<void> {
+    if (!await loadSession(payload.sessionId))
+      throw new Error('Failed to load the target chat session')
+
     const nextMessages = getSessionMessages(payload.sessionId).filter((message, messageIndex) => {
       if (payload.messageId)
         return message.id !== payload.messageId
@@ -351,65 +358,83 @@ export const useChatSessionStore = defineStore('chat-session', () => {
    * - `sessionId` exists either in `sessionMetas` or in IDB.
    *
    * Returns:
-   * - Resolves once the session is in memory. On IDB error, removes the id
+   * - `true` when the session is in memory, or `false` when hydration failed.
+   *   On IDB error, removes the id
    *   from the loading map so subsequent calls can retry rather than wedge
    *   on a stale promise. Errors are intentionally not rethrown — the
    *   failing session is simply absent from local state and the next
    *   loadSession call will retry.
    */
-  async function loadSession(sessionId: string) {
-    if (loadedSessions.has(sessionId)) {
-      return
+  async function loadSession(sessionId: string): Promise<boolean> {
+    const needsCloudHydration = () => {
+      const meta = sessionMetas.value[sessionId]
+      return !!meta?.cloudChatId && !cloudHydratedSessions.has(sessionId)
+    }
+
+    if (loadedSessions.has(sessionId) && !staleSessions.has(sessionId) && !needsCloudHydration()) {
+      return true
+    }
+    // A synchronized snapshot already carries the authority's hydrated
+    // messages. Trust it instead of letting this follower merge an older IDB
+    // record and publish that stale full-store proposal back to the leader.
+    if (Object.hasOwn(sessionMessages.value, sessionId) && hasKnownSession(sessionId) && !staleSessions.has(sessionId) && !needsCloudHydration()) {
+      loadedSessions.add(sessionId)
+      return true
     }
     if (loadingSessions.has(sessionId)) {
-      await loadingSessions.get(sessionId)
-      return
+      return await loadingSessions.get(sessionId)!
     }
 
     const loadPromise = (async () => {
       try {
-        const stored = await chatSessionsRepo.getSession(sessionId)
-        // Re-check existence: `deleteSession` (or `clearInMemoryState` on a
-        // user swap) may have run while we were awaiting IDB. Without this
-        // guard, the post-await write resurrects the deleted entry and
-        // `loadedSessions.add` then short-circuits every future legitimate
-        // load — locking the resurrection in. The drawer's batch
-        // loadSession + per-row trash button hits this race in production.
-        if (!sessionMetas.value[sessionId])
-          return
-        if (stored) {
-          const currentMessages = sessionMessages.value[sessionId] ?? []
-          const mergedMessages = mergeLoadedSessionMessages(stored.messages, currentMessages)
+        if (!loadedSessions.has(sessionId) || staleSessions.has(sessionId)) {
+          const stored = await chatSessionsRepo.getSession(sessionId)
+          // Re-check existence after the IDB read. Deletion or an account
+          // change can remove this session while the read is pending.
+          if (!sessionMetas.value[sessionId])
+            return false
+          if (staleSessions.has(sessionId) && !stored)
+            return false
+          if (stored) {
+            const currentMessages = sessionMessages.value[sessionId] ?? []
+            const mergedMessages = mergeLoadedSessionMessages(stored.messages, currentMessages)
 
-          sessionMetas.value[sessionId] = stored.meta
-          replaceSessionMessages(sessionId, mergedMessages, { persist: false })
-          ensureGeneration(sessionId)
+            sessionMetas.value[sessionId] = stored.meta
+            replaceSessionMessages(sessionId, mergedMessages, { persist: false })
+            ensureGeneration(sessionId)
 
-          if (mergedMessages !== stored.messages)
-            await persistSession(sessionId)
+            if (mergedMessages !== stored.messages)
+              await persistSession(sessionId)
+          }
+          staleSessions.delete(sessionId)
+          loadedSessions.add(sessionId)
+          if (activeSessionId.value === sessionId)
+            refreshActiveSessionSystemMessage()
         }
-        loadedSessions.add(sessionId)
-        if (activeSessionId.value === sessionId)
-          refreshActiveSessionSystemMessage()
 
-        // Cloud gap fill: when the session is mapped to a cloud chat, ask
-        // the server for everything past our highest known seq. Best
-        // effort — failures are logged inside pullCloudMessages and the
-        // local view stays usable.
-        const meta = sessionMetas.value[sessionId]
-        if (meta?.cloudChatId)
+        // Local and cloud hydration are separate. A failed cloud pull leaves
+        // the local view usable and keeps the next selection eligible to retry.
+        if (needsCloudHydration())
           await pullCloudMessages(sessionId)
+
+        // Missing IDB payloads still need a valid canonical conversation.
+        // This action runs in the elected leader, so the initialized history
+        // is published once rather than independently by every follower.
+        ensureSession(sessionId)
+
+        return true
       }
       catch (err) {
         // Do NOT add to loadedSessions on failure — the next call should
         // retry rather than fast-return on stale "already loaded" state.
         console.warn('[chat-session] loadSession failed for', sessionId, errorMessageFrom(err))
+        return false
       }
     })()
 
     loadingSessions.set(sessionId, loadPromise)
     try {
-      await loadPromise
+      return await loadPromise
     }
     finally {
       // Always drain the loading map so a transient failure does not leave
@@ -418,6 +443,13 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     }
   }
 
+  /** Forces the next session load to merge the latest IndexedDB record into memory. */
+  async function refreshSession(sessionId: string): Promise<boolean> {
+    staleSessions.add(sessionId)
+    loadedSessions.delete(sessionId)
+    return loadSession(sessionId)
+  }
+
   /**
    * Mint a new session for `characterId`, optionally seeding it with messages
    * and / or a title. Persists the new session and its index entry, then
@@ -493,26 +525,17 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   }
 
   /**
-   * Permanently remove a session from the local index + IDB and, when the
-   * session is cloud-mapped and the user is signed in, soft-delete the
-   * server chat via `DELETE /api/v1/chats/:id`.
+   * Permanently removes a session locally and tombstones its cloud identity.
    *
-   * Use when:
-   * - The user explicitly chooses "delete" from the sessions drawer.
-   *
-   * Expects:
-   * - The caller does not need to pre-confirm: this method is destructive.
-   *   When the deleted session is the active one, the store falls back to
-   *   another session for the same character or creates a fresh one.
-   *
-   * Returns:
-   * - Resolves once both local state and (if applicable) the remote DELETE
-   *   call have settled. Cloud failures are swallowed with a console.warn —
-   *   the local removal goes through either way so the user does not see
-   *   a "ghost" session after the click. A tombstone is written so the
-   *   reconcile `adopt` branch will not re-import the row on next login.
+   * Cloud failures are logged but do not restore the local session. A
+   * tombstone prevents the next reconcile from importing it again.
    */
   async function deleteSession(sessionId: string) {
+    // Keep a monotonic tombstone in memory so queued and streaming sends that
+    // captured the previous generation cannot become current again after the
+    // session record is removed.
+    bumpSessionGeneration(sessionId)
+
     const meta = sessionMetas.value[sessionId]
     if (!meta)
       return
@@ -550,8 +573,9 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     // fire-and-forget. Persistence races now read the post-deletion state.
     delete sessionMetas.value[sessionId]
     delete sessionMessages.value[sessionId]
-    delete sessionGenerations.value[sessionId]
     loadedSessions.delete(sessionId)
+    staleSessions.delete(sessionId)
+    cloudHydratedSessions.delete(sessionId)
     loadingSessions.delete(sessionId)
 
     if (index.value) {
@@ -572,42 +596,55 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     await persistIndex()
     await refreshOutboxPendingCount()
 
-    if (cloudChatId && isCloudUser) {
+    if (isCloudUser) {
+      const remoteChatId = cloudChatId ?? sessionId
       // Tombstone first: even if the cloud DELETE never reaches the server
-      // (offline, transient 5xx), the next reconcile will see the cloudChatId
+      // (offline, transient 5xx), the next reconcile will see the remote id
       // here and skip the adopt branch — preventing the ghost-session bug
       // where the server still has the row and re-creates the local mapping.
       // The reconcile-driven `drainTombstones` retries failed DELETEs.
-      await enqueuePersist(() => chatSessionsRepo.addTombstone(currentUserId, cloudChatId))
-      getCloudMapper().deleteChat(cloudChatId).then(
-        async () => {
-          // Server confirmed the delete; reconcile will not see this id again,
-          // so we can drop the tombstone.
-          await enqueuePersist(() => chatSessionsRepo.removeTombstones(currentUserId, [cloudChatId]))
-        },
-        (err) => {
-          console.warn('[chat-sync] DELETE /api/v1/chats failed for', sessionId, errorMessageFrom(err))
-        },
-      )
+      await enqueuePersist(() => chatSessionsRepo.addTombstone(currentUserId, remoteChatId))
+      if (cloudChatId) {
+        getCloudMapper().deleteChat(cloudChatId).then(
+          async () => {
+            // Server confirmed the delete; reconcile will not see this id again,
+            // so we can drop the tombstone.
+            await enqueuePersist(() => chatSessionsRepo.removeTombstones(currentUserId, [cloudChatId]))
+          },
+          (err) => {
+            console.warn('[chat-sync] DELETE /api/v1/chats failed for', sessionId, errorMessageFrom(err))
+          },
+        )
+      }
     }
 
-    // If the deleted session was active, pick another for the same
-    // character or mint a fresh one so the chat surface never lands on an
-    // empty void.
-    if (wasActive) {
-      const characterIndex = index.value?.characters[characterId]
-      const fallbackId = characterIndex
-        ? Object.keys(characterIndex.sessions).find(id => sessionMetas.value[id])
-        : undefined
-      if (fallbackId) {
+    const characterIndex = index.value?.characters[characterId]
+    const fallbackId = characterIndex
+      ? Object.keys(characterIndex.sessions).find(id => sessionMetas.value[id])
+      : undefined
+
+    // Persisted character fallback is shared, but live selection is local to
+    // the window that was displaying the deleted session.
+    if (fallbackId && characterIndex) {
+      characterIndex.activeSessionId = fallbackId
+      if (wasActive) {
         activeSessionId.value = fallbackId
-        if (characterIndex)
-          characterIndex.activeSessionId = fallbackId
         await loadSession(fallbackId)
-        await persistIndex()
       }
-      else {
-        await createSession(characterId, { setActive: true })
+      await persistIndex()
+      return
+    }
+
+    const replacementSessionId = await createSession(characterId, { setActive: wasActive })
+    if (!wasActive) {
+      // The synchronized leader may be displaying a different character, but
+      // this replacement is still the canonical fallback for the character
+      // whose final session was deleted. Persist that index choice without
+      // navigating the leader's window-local selection.
+      const replacementCharacterIndex = index.value?.characters[characterId]
+      if (replacementCharacterIndex) {
+        replacementCharacterIndex.activeSessionId = replacementSessionId
+        await persistIndex()
       }
     }
   }
@@ -644,10 +681,9 @@ export const useChatSessionStore = defineStore('chat-session', () => {
       }
 
       activeSessionId.value = characterIndex.activeSessionId
-      await loadSession(characterIndex.activeSessionId)
-      if (isStaleEpoch())
-        return
-      ensureSession(characterIndex.activeSessionId)
+      // Use the public action so follower hydration is routed to the elected
+      // leader instead of becoming a stale full-state proposal.
+      await useChatSessionStore().loadSession(characterIndex.activeSessionId)
     })()
     try {
       await ensureActivePromise
@@ -719,6 +755,7 @@ export const useChatSessionStore = defineStore('chat-session', () => {
         messages: result.messages,
         toSeq: result.seq,
       })
+      cloudHydratedSessions.add(sessionId)
     }
     catch (err) {
       console.warn('[chat-sync] pullMessages failed for', sessionId, errorMessageFrom(err))
@@ -742,6 +779,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
    * pass is scheduled in `finally` so catch-up pulls do not get lost.
    */
   async function reconcileCloudSessions(): Promise<void> {
+    if (!ownsCloudSync)
+      return
     if (cloudReconcileTask) {
       pendingReconcile = true
       return cloudReconcileTask
@@ -750,7 +789,7 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     const myEpoch = reconcileEpoch
     const isStaleEpoch = () => myEpoch !== reconcileEpoch
 
-    cloudReconcileTask = (async () => {
+    const reconcileTask = (async () => {
       const currentUserId = getCurrentUserId()
       if (currentUserId === 'local') {
         console.info('[chat-sync] reconcile skipped: anonymous user')
@@ -907,6 +946,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
 
       cloudSyncReady.value = true
     })().finally(() => {
+      if (cloudReconcileTask !== reconcileTask)
+        return
       cloudReconcileTask = undefined
       // A second 'open' event fired while we were running — schedule a
       // follow-up so its catch-up window is not lost. Skip if the epoch
@@ -920,7 +961,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
       }
     })
 
-    return cloudReconcileTask
+    cloudReconcileTask = reconcileTask
+    return reconcileTask
   }
 
   /**
@@ -929,6 +971,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
    * from the auth `watch`.
    */
   function ensureCloudWsClient() {
+    if (!ownsCloudSync)
+      return
     if (getCurrentUserId() === 'local') {
       console.info('[chat-sync] WS skipped: anonymous user')
       return
@@ -985,6 +1029,20 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     cloudMapper = undefined
   }
 
+  /** Starts or stops cloud synchronization when this window gains or loses synchronized-store leadership. */
+  function setCloudSyncOwnership(owns: boolean) {
+    if (ownsCloudSync === owns)
+      return
+
+    ownsCloudSync = owns
+    if (!ready.value)
+      return
+    if (owns)
+      ensureCloudWsClient()
+    else if (wsClient)
+      teardownCloudWsClient()
+  }
+
   /**
    * Drop every in-memory session for the current user. Used when the auth
    *  user changes — we must NOT keep account A's sessions visible (or
@@ -1002,6 +1060,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     sessionMetas.value = {}
     sessionGenerations.value = {}
     loadedSessions.clear()
+    staleSessions.clear()
+    cloudHydratedSessions.clear()
     loadingSessions.clear()
     index.value = null
     activeSessionId.value = ''
@@ -1231,7 +1291,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
       // mid-send) before the WS even opens. The drain itself runs after
       // reconcile completes, but the count is observable immediately.
       await refreshOutboxPendingCount()
-      ensureCloudWsClient()
+      if (ownsCloudSync)
+        ensureCloudWsClient()
     })()
 
     try {
@@ -1272,22 +1333,14 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     },
   })
 
-  function setActiveSession(sessionId: string) {
+  /** Selects and hydrates one conversation only in the current window. */
+  async function setActiveSession(sessionId: string) {
     activeSessionId.value = sessionId
 
-    const characterId = getCurrentCharacterId()
-    const characterIndex = index.value?.characters[characterId]
-    if (characterIndex) {
-      characterIndex.activeSessionId = sessionId
-      void persistIndex()
-    }
-
-    if (ready.value) {
-      void loadSession(sessionId)
-    }
-    else if (!hasKnownSession(sessionId)) {
+    if (ready.value)
+      await useChatSessionStore().loadSession(sessionId)
+    else if (!hasKnownSession(sessionId))
       ensureSession(sessionId)
-    }
   }
 
   function applyRemoteSnapshot(snapshot: {
@@ -1306,6 +1359,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
       Object.keys(snapshot.sessionMessages).map(sessionId => [sessionId, sessionGenerations.value[sessionId] ?? 0]),
     )
     loadedSessions.clear()
+    staleSessions.clear()
+    cloudHydratedSessions.clear()
     for (const sessionId of Object.keys(snapshot.sessionMessages)) {
       loadedSessions.add(sessionId)
     }
@@ -1349,6 +1404,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     sessionMetas.value = {}
     sessionGenerations.value = {}
     loadedSessions.clear()
+    staleSessions.clear()
+    cloudHydratedSessions.clear()
     loadingSessions.clear()
 
     index.value = {
@@ -1364,6 +1421,11 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     return sessionMessages.value[sessionId] ?? []
   }
 
+  /** Returns persisted/in-memory messages without creating an unloaded session fallback. */
+  function getSessionMessagesIfLoaded(sessionId: string) {
+    return sessionMessages.value[sessionId]
+  }
+
   function getSessionGeneration(sessionId: string) {
     ensureGeneration(sessionId)
     return sessionGenerations.value[sessionId] ?? 0
@@ -1432,6 +1494,8 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     sessionMetas.value = {}
     sessionGenerations.value = {}
     loadedSessions.clear()
+    staleSessions.clear()
+    cloudHydratedSessions.clear()
     loadingSessions.clear()
 
     await enqueuePersist(() => chatSessionsRepo.saveIndex(cloneDeep(payload.index)))
@@ -1449,6 +1513,39 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     await ensureActiveSessionForCharacter()
   }
 
+  let lastActiveSessionMeta: ChatSessionMeta | undefined
+
+  // Session data is synchronized, but selection belongs to this window. If
+  // another window deletes the selected session, repair this window locally
+  // instead of leaving it pointed at an ID that can no longer hydrate.
+  watch([
+    activeSessionId,
+    () => Object.values(sessionMetas.value),
+    () => hasKnownSession(activeSessionId.value),
+  ], ([sessionId, metas, isKnown]) => {
+    const meta = metas.find(candidate => candidate.sessionId === sessionId)
+    if (meta) {
+      lastActiveSessionMeta = meta
+      return
+    }
+    if (!sessionId || isKnown)
+      return
+
+    const characterId = lastActiveSessionMeta?.sessionId === sessionId
+      ? lastActiveSessionMeta.characterId
+      : getCurrentCharacterId()
+    const fallbackSessionId = metas
+      .find(candidate => candidate.characterId === characterId && candidate.userId === getCurrentUserId())
+      ?.sessionId
+
+    if (fallbackSessionId) {
+      void setActiveSession(fallbackSessionId)
+    }
+    // If no fallback exists yet, wait for the synchronized delete action.
+    // Its elected leader creates the single replacement; creating here in
+    // every follower would fan one deletion out into several empty chats.
+  })
+
   watch([userId, activeCardId], () => {
     if (!ready.value)
       return
@@ -1470,7 +1567,7 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   watch(userId, (next) => {
     teardownCloudWsClient()
     clearInMemoryState()
-    if (next && next !== 'local') {
+    if (ownsCloudSync && next && next !== 'local') {
       ensureCloudWsClient()
     }
     // Rehydrate for the new user. We trigger here (instead of relying on the
@@ -1485,7 +1582,6 @@ export const useChatSessionStore = defineStore('chat-session', () => {
   })
 
   return {
-    ready,
     isReady,
     initialize,
 
@@ -1505,26 +1601,32 @@ export const useChatSessionStore = defineStore('chat-session', () => {
     appendSessionMessage,
     persistSessionMessages,
     getSessionMessages,
+    getSessionMessagesIfLoaded,
     sessionMessages,
     sessionMetas,
     getSessionGeneration,
     bumpSessionGeneration,
     getSessionGenerationValue,
+    // Pinia can synchronize only refs returned by a setup store.
+    index,
 
     forkSession,
     exportSessions,
     importSessions,
     createSession,
     loadSession,
+    refreshSession,
     deleteSession,
 
+    setCloudSyncOwnership,
+
     cloudSyncReady,
     outboxPendingCount,
     pushMessageToCloud,
   }
 }, {
   synced: {
-    actions: ['deleteMessage', 'importSessions'],
+    actions: ['createSession', 'deleteMessage', 'importSessions', 'loadSession', 'refreshSession'],
     state: true,
   },
 })
diff --git a/packages/stage-ui/src/stores/mods/api/context-bridge.contract.browser.test.ts b/packages/stage-ui/src/stores/mods/api/context-bridge.contract.browser.test.ts
index c67b999ee..510b2967f 100644
--- a/packages/stage-ui/src/stores/mods/api/context-bridge.contract.browser.test.ts
+++ b/packages/stage-ui/src/stores/mods/api/context-bridge.contract.browser.test.ts
@@ -19,6 +19,7 @@ const beginStreamMock = vi.fn()
 const appendStreamLiteralMock = vi.fn()
 const finalizeStreamMock = vi.fn()
 const resetStreamMock = vi.fn()
+const refreshSessionMock = vi.fn()
 const serverSendMock = vi.fn()
 const ensureConnectedMock = vi.fn().mockResolvedValue(undefined)
 const onReconnectedMock = vi.fn(() => () => {})
@@ -157,6 +158,7 @@ function createContextUpdateEvent(overrides: Record<string, unknown> = {}) {
 }
 
 const chatOrchestratorMock = {
+  activeSendSessionId: undefined as string | undefined,
   sending: false,
   ingest: vi.fn(),
 
@@ -237,6 +239,7 @@ vi.mock('../../chat/session-store', () => ({
       return activeSessionIdRef.value
     },
     getSessionGenerationValue: () => currentGeneration,
+    refreshSession: (sessionId: string) => refreshSessionMock(sessionId),
   }),
 }))
 
@@ -291,6 +294,7 @@ describe('context bridge contract', () => {
     appendStreamLiteralMock.mockReset()
     finalizeStreamMock.mockReset()
     resetStreamMock.mockReset()
+    refreshSessionMock.mockReset().mockResolvedValue(true)
     serverSendMock.mockReset()
     ensureConnectedMock.mockClear()
     ensureConnectedMock.mockResolvedValue(undefined)
@@ -304,6 +308,7 @@ describe('context bridge contract', () => {
     activeProviderRef.value = null
     activeModelRef.value = null
     activeSessionIdRef.value = 'session-1'
+    chatOrchestratorMock.activeSendSessionId = undefined
     currentGeneration = 7
     chatOrchestratorMock.sending = false
 
@@ -325,10 +330,6 @@ describe('context bridge contract', () => {
     closeTestChannels()
   })
 
-  /**
-   * @example
-   * Broadcast context updates record store-ingested with core result fields.
-   */
   it('records core ingest result for broadcast context updates', async () => {
     chatContextIngestMock.mockReturnValueOnce({
       sourceKey: 'weather:station-1',
@@ -361,10 +362,6 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  /**
-   * @example
-   * Server context updates record store-ingested before broadcast-posted.
-   */
   it('records core ingest result for server context updates before broadcasting', async () => {
     chatContextIngestMock.mockReturnValueOnce({
       sourceKey: 'weather:station-1',
@@ -399,10 +396,6 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  /**
-   * @example
-   * Input context updates record store-ingested and stay in chat input payload.
-   */
   it('records core ingest result for input context updates and forwards accepted updates', async () => {
     chatContextIngestMock.mockReturnValueOnce({
       sourceKey: 'weather:station-1',
@@ -453,10 +446,6 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  /**
-   * @example
-   * Broadcast context ingest failures record store-ingest-rejected instead of escaping.
-   */
   it('records rejected lifecycle for broadcast ingest failures without interrupting the watcher', async () => {
     chatContextIngestMock.mockImplementationOnce(() => {
       throw new Error('Cannot clone broadcast context')
@@ -485,10 +474,6 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  /**
-   * @example
-   * Server context ingest failures are not rebroadcast.
-   */
   it('records rejected lifecycle and skips broadcast when server context ingest fails', async () => {
     chatContextIngestMock.mockImplementationOnce(() => {
       throw new Error('Cannot clone server context')
@@ -520,10 +505,6 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  /**
-   * @example
-   * Input context ingest failures drop only the failed context update.
-   */
   it('records rejected lifecycle and continues text ingestion when input context ingest fails', async () => {
     chatContextIngestMock.mockImplementationOnce(() => {
       throw new Error('Cannot clone input context')
@@ -562,7 +543,14 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
-  it('replays remote stream lifecycle into sending and stream store APIs', async () => {
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3743366445
+  it('keeps a remote stream visible locally without publishing chat authority state for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // Stage Pocket uses plain Pinia, so remote stream tokens update only the
+    // local stream store. The history requires a sending flag, but writing
+    // that flag to the synchronized chat store would let a follower overwrite
+    // the elected authority's stream snapshot.
     const store = useContextBridgeStore()
     await store.initialize()
     const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
@@ -574,18 +562,19 @@ describe('context bridge contract', () => {
       composedMessage: [],
     } satisfies ChatStreamEventContext
 
-    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'session-1', context })
     await vi.waitFor(() => {
-      expect(chatOrchestratorMock.sending).toBe(true)
       expect(beginStreamMock).toHaveBeenCalledWith('turn-1')
     })
+    expect(chatOrchestratorMock.sending).toBe(false)
+    expect(store.isReceivingRemoteStream).toBe(true)
 
-    streamSender.postMessage({ type: 'token-literal', literal: 'hello', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'token-literal', literal: 'hello', sessionId: 'session-1', context })
     await vi.waitFor(() => {
       expect(appendStreamLiteralMock).toHaveBeenCalledWith('hello')
     })
 
-    streamSender.postMessage({ type: 'assistant-end', message: 'final answer', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'assistant-end', message: 'final answer', sessionId: 'session-1', context })
     await vi.waitFor(() => {
       expect(resetStreamMock).toHaveBeenCalledTimes(1)
     })
@@ -594,6 +583,7 @@ describe('context bridge contract', () => {
     // to avoid corrupting history by persisting a duplicate assistant message.
     expect(finalizeStreamMock).not.toHaveBeenCalled()
     expect(chatOrchestratorMock.sending).toBe(false)
+    expect(store.isReceivingRemoteStream).toBe(false)
 
     await store.dispose()
   })
@@ -624,6 +614,166 @@ describe('context bridge contract', () => {
     await store.dispose()
   })
 
+  it('labels outbound stream events with the session that owns the send', async () => {
+    const outgoingStreamMessages = collectChannelMessages<{ sessionId: string }>(CHAT_STREAM_CHANNEL_NAME)
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const context = {
+      turnId: 'turn-1',
+      message: { role: 'user', content: 'ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+
+    chatOrchestratorMock.activeSendSessionId = 'session-a'
+    activeSessionIdRef.value = 'session-b'
+    await chatOrchestratorMock.emitTokenLiteralHooks('session A token', context)
+    await vi.waitFor(() => expect(outgoingStreamMessages).toHaveLength(1))
+
+    expect(outgoingStreamMessages[0]?.sessionId).toBe('session-a')
+    await store.dispose()
+  })
+
+  it('clears remote stream visibility when an end hook rejects', async () => {
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
+    const context = {
+      turnId: 'turn-1',
+      message: { role: 'user', content: 'ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+    chatOrchestratorMock.onStreamEnd(async () => {
+      throw new Error('end hook failed')
+    })
+    vi.spyOn(console, 'error').mockImplementation(() => {})
+
+    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'session-1', context })
+    await vi.waitFor(() => expect(store.isReceivingRemoteStream).toBe(true))
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-1', context })
+    await vi.waitFor(() => expect(store.isReceivingRemoteStream).toBe(false))
+
+    expect(resetStreamMock).toHaveBeenCalledTimes(1)
+    await store.dispose()
+  })
+
+  it('ignores stream events that do not match the active remote session', async () => {
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
+    const context = {
+      turnId: 'turn-1',
+      message: { role: 'user', content: 'ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+
+    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'session-1', context })
+    await vi.waitFor(() => expect(store.isReceivingRemoteStream).toBe(true))
+    streamSender.postMessage({ type: 'token-literal', literal: 'foreign token', sessionId: 'session-2', context })
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-2', context })
+    await waitForBroadcastDelivery()
+
+    expect(appendStreamLiteralMock).not.toHaveBeenCalledWith('foreign token')
+    expect(store.isReceivingRemoteStream).toBe(true)
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-1', context })
+    await vi.waitFor(() => expect(store.isReceivingRemoteStream).toBe(false))
+    await store.dispose()
+  })
+
+  it('does not replace the foreground stream for an inactive remote session', async () => {
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
+    const context = {
+      turnId: 'turn-2',
+      message: { role: 'user', content: 'background ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+
+    streamSender.postMessage({ type: 'before-send', message: 'background ping', sessionId: 'session-2', context })
+    await waitForBroadcastDelivery()
+    expect(beginStreamMock).not.toHaveBeenCalled()
+    expect(store.isReceivingRemoteStream).toBe(false)
+
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-2', context })
+    await waitForBroadcastDelivery()
+    expect(resetStreamMock).not.toHaveBeenCalled()
+    await store.dispose()
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3755585351
+  it('keeps remote literals received before a mid-stream session switch for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // The bridge discarded literals while their session was not selected.
+    // Selecting that session during the stream showed only later literals.
+    activeSessionIdRef.value = 'session-2'
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
+    const context = {
+      turnId: 'turn-3',
+      message: { role: 'user', content: 'background ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+
+    streamSender.postMessage({ type: 'before-send', message: 'background ping', sessionId: 'session-1', context })
+    streamSender.postMessage({ type: 'token-literal', literal: 'first half ', sessionId: 'session-1', context })
+    await waitForBroadcastDelivery()
+    expect(beginStreamMock).not.toHaveBeenCalled()
+    expect(appendStreamLiteralMock).not.toHaveBeenCalled()
+
+    activeSessionIdRef.value = 'session-1'
+    streamSender.postMessage({ type: 'token-literal', literal: 'second half', sessionId: 'session-1', context })
+
+    await vi.waitFor(() => expect(appendStreamLiteralMock).toHaveBeenCalledTimes(2))
+    expect(beginStreamMock).toHaveBeenCalledWith('turn-3')
+    expect(appendStreamLiteralMock).toHaveBeenNthCalledWith(1, 'first half ')
+    expect(appendStreamLiteralMock).toHaveBeenNthCalledWith(2, 'second half')
+
+    await store.dispose()
+  })
+
+  // https://github.com/moeru-ai/airi/pull/2086#discussion_r3755711154
+  it('reloads a completed remote stream when its Pocket session becomes active for Issue #2085', async () => {
+    // ROOT CAUSE:
+    //
+    // A plain-Pinia Pocket tab discarded a completed background stream.
+    // Its loaded-session cache then prevented a later IndexedDB refresh.
+    activeSessionIdRef.value = 'session-1'
+    const store = useContextBridgeStore()
+    await store.initialize()
+    const streamSender = createTestChannel(CHAT_STREAM_CHANNEL_NAME)
+    const context = {
+      turnId: 'turn-4',
+      message: { role: 'user', content: 'background ping' },
+      contexts: {},
+      composedMessage: [],
+    } satisfies ChatStreamEventContext
+
+    streamSender.postMessage({ type: 'before-send', message: 'background ping', sessionId: 'session-2', context })
+    streamSender.postMessage({ type: 'token-literal', literal: 'complete answer', sessionId: 'session-2', context })
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-2', context })
+    streamSender.postMessage({ type: 'assistant-end', message: 'complete answer', sessionId: 'session-2', context })
+    await waitForBroadcastDelivery()
+
+    expect(refreshSessionMock).not.toHaveBeenCalled()
+    expect(resetStreamMock).not.toHaveBeenCalled()
+
+    activeSessionIdRef.value = 'session-2'
+    await vi.waitFor(() => expect(refreshSessionMock).toHaveBeenCalledWith('session-2'))
+    await vi.waitFor(() => expect(resetStreamMock).toHaveBeenCalledTimes(1))
+    expect(beginStreamMock).toHaveBeenCalledWith('turn-4')
+    expect(appendStreamLiteralMock).toHaveBeenCalledWith('complete answer')
+    expect(store.isReceivingRemoteStream).toBe(false)
+
+    await store.dispose()
+  })
+
   it('ignores remote literal and end events when generation guard is stale', async () => {
     const store = useContextBridgeStore()
     await store.initialize()
@@ -636,21 +786,22 @@ describe('context bridge contract', () => {
       composedMessage: [],
     } satisfies ChatStreamEventContext
 
-    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'before-send', message: 'ping', sessionId: 'session-1', context })
     await vi.waitFor(() => {
       expect(beginStreamMock).toHaveBeenCalledWith('turn-1')
     })
 
     currentGeneration = 8
-    streamSender.postMessage({ type: 'token-literal', literal: 'stale-literal', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'token-literal', literal: 'stale-literal', sessionId: 'session-1', context })
     await waitForBroadcastDelivery()
 
-    streamSender.postMessage({ type: 'stream-end', sessionId: 'remote-session', context })
+    streamSender.postMessage({ type: 'stream-end', sessionId: 'session-1', context })
     await waitForBroadcastDelivery()
 
     expect(appendStreamLiteralMock).not.toHaveBeenCalledWith('stale-literal')
     expect(finalizeStreamMock).not.toHaveBeenCalled()
-    expect(chatOrchestratorMock.sending).toBe(true)
+    expect(chatOrchestratorMock.sending).toBe(false)
+    expect(store.isReceivingRemoteStream).toBe(false)
 
     await store.dispose()
   })
diff --git a/packages/stage-ui/src/stores/mods/api/context-bridge.ts b/packages/stage-ui/src/stores/mods/api/context-bridge.ts
index f5d60ec4f..61b3546b2 100644
--- a/packages/stage-ui/src/stores/mods/api/context-bridge.ts
+++ b/packages/stage-ui/src/stores/mods/api/context-bridge.ts
@@ -12,7 +12,7 @@ import { useBroadcastChannel } from '@vueuse/core'
 import { Mutex } from 'es-toolkit'
 import { nanoid } from 'nanoid'
 import { defineStore, storeToRefs } from 'pinia'
-import { ref, toRaw, watch } from 'vue'
+import { computed, ref, shallowRef, toRaw, watch } from 'vue'
 
 import { getEventSourceKey, getMetadataSourceLabel } from '../../../utils/event-source'
 import { useLlmStreamingControlStore } from '../../ai/chat-llm/streaming-control'
@@ -89,10 +89,61 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
   const { post: postSparkNotifyBridgeMessage, data: incomingSparkNotifyBridgeMessage } = useBroadcastChannel<SparkNotifyBridgeMessage, SparkNotifyBridgeMessage>({ name: SPARK_NOTIFY_BRIDGE_CHANNEL_NAME })
 
   const disposeHookFns = ref<Array<() => void>>([])
-  let remoteStreamGuard: { sessionId: string, generation: number } | null = null
+  // Remote stream data belongs to this renderer only. Keeping its visibility
+  // outside the synchronized chat store prevents a follower from publishing
+  // its local runtime state over the elected authority's snapshot.
+  const remoteStreamGuard = shallowRef<{
+    sessionId: string
+    generation: number
+    turnId: string
+    started: boolean
+    completed: boolean
+    refreshing: boolean
+    pendingLiterals: string[]
+  }>()
+  const isReceivingRemoteStream = computed(() => remoteStreamGuard.value?.sessionId === chatSession.activeSessionId)
   let contextChannel: ReturnType<typeof createContextChannel> | undefined
   let initialized = false
 
+  function presentRemoteStreamIfActive() {
+    const guard = remoteStreamGuard.value
+    if (!guard || guard.sessionId !== chatSession.activeSessionId)
+      return false
+    if (chatSession.getSessionGenerationValue(guard.sessionId) !== guard.generation)
+      return false
+
+    if (!guard.started) {
+      guard.started = true
+      chatStream.beginStream(guard.turnId)
+    }
+    for (const literal of guard.pendingLiterals.splice(0))
+      chatStream.appendStreamLiteral(literal)
+    if (guard.completed && !guard.refreshing)
+      void refreshCompletedRemoteStream(guard)
+    return true
+  }
+
+  async function refreshCompletedRemoteStream(guard: NonNullable<typeof remoteStreamGuard.value>) {
+    guard.refreshing = true
+    let loaded = false
+    try {
+      loaded = await chatSession.refreshSession(guard.sessionId)
+    }
+    catch (error) {
+      console.warn('[context-bridge] Failed to refresh completed remote stream:', errorMessageFrom(error))
+    }
+    if (remoteStreamGuard.value !== guard)
+      return
+    guard.refreshing = false
+    if (!loaded || guard.sessionId !== chatSession.activeSessionId)
+      return
+    if (chatSession.getSessionGenerationValue(guard.sessionId) !== guard.generation)
+      return
+
+    chatStream.resetStream()
+    remoteStreamGuard.value = undefined
+  }
+
   function recordContextIngestRejected(options: {
     channel: 'server' | 'broadcast' | 'input'
     contextMessage: ContextMessage
@@ -699,49 +750,49 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'before-compose', message, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'before-compose', message, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onAfterMessageComposed(async (message, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'after-compose', message, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'after-compose', message, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onBeforeSend(async (message, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'before-send', message, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'before-send', message, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onAfterSend(async (message, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'after-send', message, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'after-send', message, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onTokenLiteral(async (literal, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'token-literal', literal, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'token-literal', literal, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onTokenSpecial(async (special, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'token-special', special, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'token-special', special, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onStreamEnd(async (context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'stream-end', sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'stream-end', sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
         chatOrchestrator.onAssistantResponseEnd(async (message, context) => {
           if (isProcessingRemoteStream)
             return
 
-          await contextChannel?.emitStream({ type: 'assistant-end', message, sessionId: chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
+          await contextChannel?.emitStream({ type: 'assistant-end', message, sessionId: chatOrchestrator.activeSendSessionId ?? chatSession.activeSessionId, context: structuredClone(normalizeContextSnapshot(context)) })
         }),
 
         chatOrchestrator.onAssistantMessage(async (message, _messageText, context) => {
@@ -794,7 +845,8 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
         isProcessingRemoteStream = true
 
         try {
-          // Use the receiver's active session to avoid clobbering chat state when events come from other windows/devtools.
+          // Remote UI state is correlated by session and generation. The
+          // receiver never persists these mirrored stream events.
           switch (event.type) {
             case 'before-compose':
               await chatOrchestrator.emitBeforeMessageComposedHooks(event.message, event.context)
@@ -804,58 +856,99 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
               break
             case 'before-send':
               await chatOrchestrator.emitBeforeSendHooks(event.message, event.context)
-              remoteStreamGuard = {
-                sessionId: chatSession.activeSessionId,
-                generation: chatSession.getSessionGenerationValue(chatSession.activeSessionId),
+              remoteStreamGuard.value = {
+                sessionId: event.sessionId,
+                generation: chatSession.getSessionGenerationValue(event.sessionId),
+                turnId: event.context.turnId,
+                started: false,
+                completed: false,
+                refreshing: false,
+                pendingLiterals: [],
               }
-              chatOrchestrator.sending = true
-              chatStream.beginStream(event.context.turnId)
+              presentRemoteStreamIfActive()
               break
             case 'after-send':
               await chatOrchestrator.emitAfterSendHooks(event.message, event.context)
               break
             case 'token-literal':
-              if (!remoteStreamGuard)
+              if (!remoteStreamGuard.value)
                 return
-              if (remoteStreamGuard.sessionId !== chatSession.activeSessionId)
+              if (event.sessionId !== remoteStreamGuard.value.sessionId)
                 return
-              if (chatSession.getSessionGenerationValue(remoteStreamGuard.sessionId) !== remoteStreamGuard.generation)
+              if (chatSession.getSessionGenerationValue(remoteStreamGuard.value.sessionId) !== remoteStreamGuard.value.generation)
+                return
+              remoteStreamGuard.value.pendingLiterals.push(event.literal)
+              if (!presentRemoteStreamIfActive())
                 return
-              chatStream.appendStreamLiteral(event.literal)
               await chatOrchestrator.emitTokenLiteralHooks(event.literal, event.context)
               break
             case 'token-special':
+              if (!remoteStreamGuard.value || event.sessionId !== remoteStreamGuard.value.sessionId)
+                return
+              if (remoteStreamGuard.value.sessionId !== chatSession.activeSessionId)
+                return
+              if (chatSession.getSessionGenerationValue(remoteStreamGuard.value.sessionId) !== remoteStreamGuard.value.generation)
+                return
               await chatOrchestrator.emitTokenSpecialHooks(event.special, event.context)
               break
             case 'stream-end':
-              if (!remoteStreamGuard)
+              if (!remoteStreamGuard.value)
                 break
-              if (remoteStreamGuard.sessionId !== chatSession.activeSessionId)
-                break
-              if (chatSession.getSessionGenerationValue(remoteStreamGuard.sessionId) !== remoteStreamGuard.generation)
-                break
-              await chatOrchestrator.emitStreamEndHooks(event.context)
-              // NOTICE: Remote stream events are mirrored across renderer windows for UI feedback only.
-              // Persisting them here would append assistant messages into the receiver's local session
-              // without the corresponding user message, corrupting IndexedDB history across windows.
-              chatStream.resetStream()
-              chatOrchestrator.sending = false
-              remoteStreamGuard = null
+              {
+                const guard = remoteStreamGuard.value
+                if (event.sessionId !== guard.sessionId)
+                  break
+                if (guard.sessionId !== chatSession.activeSessionId
+                  && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                  break
+                }
+                try {
+                  if (guard.sessionId === chatSession.activeSessionId
+                    && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                    await chatOrchestrator.emitStreamEndHooks(event.context)
+                  }
+                }
+                finally {
+                  if (remoteStreamGuard.value === guard) {
+                    if (guard.started
+                      && guard.sessionId === chatSession.activeSessionId
+                      && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                      chatStream.resetStream()
+                    }
+                    remoteStreamGuard.value = undefined
+                  }
+                }
+              }
               break
             case 'assistant-end':
-              if (!remoteStreamGuard)
+              if (!remoteStreamGuard.value)
                 break
-              if (remoteStreamGuard.sessionId !== chatSession.activeSessionId)
-                break
-              if (chatSession.getSessionGenerationValue(remoteStreamGuard.sessionId) !== remoteStreamGuard.generation)
-                break
-              await chatOrchestrator.emitAssistantResponseEndHooks(event.message, event.context)
-              // NOTICE: The originating renderer already persists the final assistant message.
-              // Receiver windows must not write it again, or they can overwrite the same session
-              // with assistant-only history when their local session state is stale.
-              chatStream.resetStream()
-              chatOrchestrator.sending = false
-              remoteStreamGuard = null
+              {
+                const guard = remoteStreamGuard.value
+                if (event.sessionId !== guard.sessionId)
+                  break
+                if (guard.sessionId !== chatSession.activeSessionId
+                  && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                  guard.completed = true
+                  break
+                }
+                try {
+                  if (guard.sessionId === chatSession.activeSessionId
+                    && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                    await chatOrchestrator.emitAssistantResponseEndHooks(event.message, event.context)
+                  }
+                }
+                finally {
+                  if (remoteStreamGuard.value === guard) {
+                    if (guard.started
+                      && guard.sessionId === chatSession.activeSessionId
+                      && chatSession.getSessionGenerationValue(guard.sessionId) === guard.generation) {
+                      chatStream.resetStream()
+                    }
+                    remoteStreamGuard.value = undefined
+                  }
+                }
+              }
               break
           }
         }
@@ -864,6 +957,11 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
         }
       })
       disposeHookFns.value.push(stopIncomingStreamWatch)
+      disposeHookFns.value.push(watch(
+        () => chatSession.activeSessionId,
+        () => presentRemoteStreamIfActive(),
+        { flush: 'sync' },
+      ))
       initialized = true
     }
     catch (error) {
@@ -905,7 +1003,7 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
       contextChannel = undefined
 
       initialized = false
-      remoteStreamGuard = null
+      remoteStreamGuard.value = undefined
 
       for (const [requestId, waiter] of sparkNotifyBridgeWaiters) {
         if (waiter.timeout)
@@ -925,6 +1023,7 @@ export const useContextBridgeStore = defineStore('mods:api:context-bridge', () =
     dispose,
     dispatchSparkNotifyReaction,
     dispatchSparkNotifyPerformance,
+    isReceivingRemoteStream,
     setSparkNotifyHostRole,
   }
 })
diff --git a/vitest.config.ts b/vitest.config.ts
index 112cd5a37..515becfc4 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -6,7 +6,7 @@ export default defineConfig({
       'server/apps/auth',
       'server/apps/api',
       'apps/ui-server-auth',
-      'apps/stage-tamagotchi',
+      'apps/stage-tamagotchi/vitest.node.config.ts',
       'packages/cap-vite',
       'packages/ccc',
       'packages/core-agent',