Bound tab recency sync pressure

src/components/TerminalView.tsx

@@ -28,6 +28,7 @@ import { focusNextTerminalSearchMatch, focusPreviousTerminalSearchMatch, loadTer
 import { isFatalConnectionErrorCode } from '@/store/connectionSlice'
 import { buildTerminalDurableSessionRefUpdate, flushPersistedLayoutNow } from '@/store/persistControl'
 import { getWsClient } from '@/lib/ws-client'
+import { bucketTabRecencyAt } from '@/lib/tab-recency'
 import { getTerminalTheme } from '@/lib/terminal-themes'
 import { getCreateSessionStateFromRef } from '@/components/terminal-view-utils'
 import { copyText, readText } from '@/lib/clipboard'
@@ -105,6 +106,7 @@ import {
 } from '@/lib/terminal-behavior'
 import { buildRestoreError } from '@shared/session-contract'
 import type { CodingCliProviderName } from '@/store/types'
+import { recordPaneTabActivity } from '@/store/tabRecencySlice'
 
 const log = createLogger('TerminalView')
 
@@ -323,6 +325,7 @@ function TerminalView({ tabId, paneId, paneContent, hidden }: TerminalViewProps)
   const hasAttentionRef = useRef(hasAttention)
   const hasPaneAttention = useAppSelector((s) => !!s.turnCompletion?.attentionByPane?.[paneId])
   const hasPaneAttentionRef = useRef(hasPaneAttention)
+  const paneTabRecencyBucket = useAppSelector((s) => s.tabRecency?.paneLastInputAt?.[paneId])
 
   // All hooks MUST be called before any conditional returns
   const ws = useMemo(() => getWsClient(), [])
@@ -359,6 +362,7 @@ function TerminalView({ tabId, paneId, paneContent, hidden }: TerminalViewProps)
   const hiddenRef = useRef(hidden)
   const hydrationRegisteredRef = useRef(false)
   const lastSessionActivityAtRef = useRef(0)
+  const lastPaneTabRecencyBucketRef = useRef<number | undefined>(paneTabRecencyBucket)
   const rateLimitRetryRef = useRef<{ count: number; timer: ReturnType<typeof setTimeout> | null }>({ count: 0, timer: null })
   const restoreRequestIdRef = useRef<string | null>(null)
   const restoreFlagRef = useRef(false)
@@ -504,6 +508,10 @@ function TerminalView({ tabId, paneId, paneContent, hidden }: TerminalViewProps)
     }
   }, [terminalContent, paneId, applySeqState])
 
+  useEffect(() => {
+    lastPaneTabRecencyBucketRef.current = paneTabRecencyBucket
+  }, [paneId, paneTabRecencyBucket])
+
   // Register terminal buffer accessor with test harness (for E2E tests).
   // Uses xterm.js Terminal.buffer.active API which works with all renderers
   // (WebGL, canvas, DOM) — unlike DOM scraping via .xterm-rows which only
@@ -1357,7 +1365,12 @@ function TerminalView({ tabId, paneId, paneContent, hidden }: TerminalViewProps)
       const currentContent = contentRef.current
       if (currentTab) {
         const now = Date.now()
-        dispatch(updateTab({ id: currentTab.id, updates: { lastInputAt: now } }))
+        const bucket = bucketTabRecencyAt(now)
+        const previousBucket = lastPaneTabRecencyBucketRef.current
+        if (bucket !== undefined && (previousBucket === undefined || bucket > previousBucket)) {
+          lastPaneTabRecencyBucketRef.current = bucket
+          dispatch(recordPaneTabActivity({ paneId, at: now }))
+        }
         const resumeSessionId = currentContent?.resumeSessionId
         if (resumeSessionId && currentContent?.mode && currentContent.mode !== 'shell') {
           if (now - lastSessionActivityAtRef.current >= SESSION_ACTIVITY_THROTTLE_MS) {

src/components/context-menu/ContextMenuProvider.tsx

@@ -30,6 +30,7 @@ import type { ClientExtensionEntry } from '@shared/extension-types'
 import { buildResumeContent } from '@/lib/session-type-utils'
 import { getAgentChatProviderConfig } from '@/lib/agent-chat-utils'
 import { mergeSessionMetadataByKey } from '@/lib/session-metadata'
+import { deriveTabRecencyAt } from '@/lib/tab-recency'
 import { ConfirmModal } from '@/components/ui/confirm-modal'
 import type { AppView } from '@/components/Sidebar'
 import type { CodingCliProviderName, CodingCliSession, ProjectGroup } from '@/store/types'
@@ -51,6 +52,8 @@ import { nanoid } from 'nanoid'
 
 const CONTEXT_MENU_KEYS = ['ContextMenu']
 const EMPTY_EXTENSION_ENTRIES: ClientExtensionEntry[] = []
+const EMPTY_PANE_LAST_INPUT_AT: Record<string, number | undefined> = {}
+const EMPTY_FEATURE_FLAGS: Record<string, boolean> = {}
 
 
 type MenuState = {
@@ -107,9 +110,10 @@ export function ContextMenuProvider({
   const historySessions = useAppSelector((s) => s.sessions.windows?.history?.projects ?? s.sessions.projects)
   const expandedProjects = useAppSelector((s) => s.sessions.expandedProjects)
   const platform = useAppSelector((s) => s.connection?.platform ?? null)
-  const featureFlags = useAppSelector((s) => s.connection?.featureFlags ?? {})
+  const featureFlags = useAppSelector((s) => s.connection?.featureFlags ?? EMPTY_FEATURE_FLAGS)
   const appSettings = useAppSelector((s) => s.settings.settings)
   const extensionEntries = useAppSelector((s) => s.extensions?.entries ?? EMPTY_EXTENSION_ENTRIES)
+  const paneLastInputAt = useAppSelector((s) => s.tabRecency?.paneLastInputAt ?? EMPTY_PANE_LAST_INPUT_AT)
 
   const [menuState, setMenuState] = useState<MenuState | null>(null)
   const [confirmState, setConfirmState] = useState<ConfirmState | null>(null)
@@ -523,7 +527,14 @@ export function ContextMenuProvider({
       return refs.some((ref) => ref.provider === keyProvider && ref.sessionId === sessionId)
     })
     const hasTab = relatedTabs.length > 0
-    const tabLastInputAt = relatedTabs.reduce((max, tab) => Math.max(max, tab.lastInputAt ?? 0), 0) || undefined
+    const tabLastInputAt = relatedTabs.reduce((max, tab) => {
+      const layout = panes[tab.id]
+      return Math.max(max, deriveTabRecencyAt({
+        tab,
+        layout,
+        paneLastInputAt,
+      }))
+    }, 0)
     const runningTerminalId =
       menuState?.target.kind === 'sidebar-session' && menuState?.target.sessionId === sessionId
         ? menuState?.target.runningTerminalId
@@ -544,14 +555,14 @@ export function ContextMenuProvider({
       archived: session.archived,
       sourceFile: session.sourceFile,
       hasTab,
-      tabLastInputAt,
-      tabLastInputAtIso: tabLastInputAt ? new Date(tabLastInputAt).toISOString() : null,
+      tabLastInputAt: hasTab ? tabLastInputAt : undefined,
+      tabLastInputAtIso: hasTab ? new Date(tabLastInputAt).toISOString() : null,
       isRunning: !!runningTerminalId,
       runningTerminalId: runningTerminalId || null,
       projectColor: project.color,
     }
     await copyText(JSON.stringify(metadata, null, 2))
-  }, [getSessionInfo, tabsState.tabs, panes, menuState?.target])
+  }, [getSessionInfo, tabsState.tabs, panes, paneLastInputAt, menuState?.target])
 
   const copyResumeCommand = useCallback(async (provider: ResumeCommandProvider, sessionId: string) => {
     const command = buildResumeCommand(provider, sessionId, extensionEntries)

src/lib/tab-recency.ts

@@ -0,0 +1,39 @@
+import type { PaneNode } from '@/store/paneTypes'
+import type { Tab } from '@/store/types'
+
+export const TAB_RECENCY_RESOLUTION_MS = 60 * 1000
+
+type TimestampCandidate = number | null | undefined
+
+export function bucketTabRecencyAt(at: TimestampCandidate): number | undefined {
+  if (typeof at !== 'number' || !Number.isFinite(at) || at < 0) return undefined
+  return Math.floor(at / TAB_RECENCY_RESOLUTION_MS) * TAB_RECENCY_RESOLUTION_MS
+}
+
+export function collectTerminalPaneIds(node: PaneNode | undefined): string[] {
+  if (!node) return []
+  if (node.type === 'leaf') {
+    return node.content.kind === 'terminal' ? [node.id] : []
+  }
+  return [
+    ...collectTerminalPaneIds(node.children[0]),
+    ...collectTerminalPaneIds(node.children[1]),
+  ]
+}
+
+export function deriveTabRecencyAt(input: {
+  tab: Pick<Tab, 'createdAt' | 'lastInputAt'>
+  layout: PaneNode | undefined
+  paneLastInputAt: Record<string, number | undefined>
+}): number {
+  const candidates: number[] = []
+  for (const raw of [input.tab.createdAt, input.tab.lastInputAt]) {
+    const bucket = bucketTabRecencyAt(raw)
+    if (bucket !== undefined) candidates.push(bucket)
+  }
+  for (const paneId of collectTerminalPaneIds(input.layout)) {
+    const bucket = bucketTabRecencyAt(input.paneLastInputAt[paneId])
+    if (bucket !== undefined) candidates.push(bucket)
+  }
+  return candidates.length > 0 ? Math.max(...candidates) : 0
+}

src/store/crossTabSync.ts

@@ -8,7 +8,13 @@ import { getPendingBrowserPreferencesWriteState } from './browserPreferencesPers
 import { parsePersistedLayoutRaw, LAYOUT_STORAGE_KEY } from './persistedState'
 import { getPersistBroadcastSourceId, onPersistBroadcast, PERSIST_BROADCAST_CHANNEL_NAME } from './persistBroadcast'
 import { shouldPreserveLocalCanonicalResumeSessionId } from './persistControl'
-import { BROWSER_PREFERENCES_STORAGE_KEY } from './storage-keys'
+import { BROWSER_PREFERENCES_STORAGE_KEY, TAB_RECENCY_STORAGE_KEY } from './storage-keys'
+import { collectLiveTerminalPaneIds } from './tabRecencyPruneMiddleware'
+import {
+  loadPersistedTabRecency,
+  mergeHydratedTabRecency,
+  prunePaneTabActivityToLiveTerminalPanes,
+} from './tabRecencySlice'
 import { parseBrowserPreferencesRaw, resolveBrowserPreferenceSettings } from '@/lib/browser-preferences'
 
 type StoreLike = {
@@ -25,6 +31,12 @@ const zPersistBroadcastMsg = z.object({
   sourceId: z.string(),
 })
 
+const CROSS_TAB_SYNC_STORAGE_KEYS = [
+  LAYOUT_STORAGE_KEY,
+  BROWSER_PREFERENCES_STORAGE_KEY,
+  TAB_RECENCY_STORAGE_KEY,
+] as const
+
 function collectPaneIdsSafe(node: unknown): string[] {
   const ids: string[] = []
 
@@ -260,6 +272,17 @@ function handleIncomingRaw(
     dispatchHydrateLayoutFromPersisted(store, raw, localLayoutPersistedAt)
   } else if (key === BROWSER_PREFERENCES_STORAGE_KEY) {
     dispatchHydrateBrowserPreferencesFromPersisted(store, raw, previousRaw)
+  } else if (key === TAB_RECENCY_STORAGE_KEY) {
+    store.dispatch({
+      ...mergeHydratedTabRecency(loadPersistedTabRecency(raw)),
+      meta: { skipPersist: true, source: 'cross-tab' },
+    })
+    store.dispatch({
+      ...prunePaneTabActivityToLiveTerminalPanes({
+        paneIds: collectLiveTerminalPaneIds(store.getState()),
+      }),
+      meta: { source: 'cross-tab' },
+    })
   }
 }
 
@@ -270,7 +293,7 @@ export function installCrossTabSync(store: StoreLike): () => void {
   // Dedupe by exact raw value so we don't hydrate twice.
   const lastProcessedRawByKey = new Map<string, string>()
   let currentLocalLayoutPersistedAt: number | undefined
-  for (const key of [LAYOUT_STORAGE_KEY, BROWSER_PREFERENCES_STORAGE_KEY]) {
+  for (const key of CROSS_TAB_SYNC_STORAGE_KEYS) {
     const existingRaw = localStorage.getItem(key)
     if (typeof existingRaw === 'string') {
       lastProcessedRawByKey.set(key, existingRaw)
@@ -307,10 +330,7 @@ export function installCrossTabSync(store: StoreLike): () => void {
   // then diverge locally (persisted raw changes), a later remote event with the original raw
   // could be incorrectly ignored.
   const unsubscribeLocal = onPersistBroadcast((msg) => {
-    if (
-      msg.key !== LAYOUT_STORAGE_KEY
-      && msg.key !== BROWSER_PREFERENCES_STORAGE_KEY
-    ) {
+    if (!CROSS_TAB_SYNC_STORAGE_KEYS.includes(msg.key as any)) {
       return
     }
     lastProcessedRawByKey.set(msg.key, msg.raw)
@@ -322,10 +342,7 @@ export function installCrossTabSync(store: StoreLike): () => void {
   const onStorage = (e: StorageEvent) => {
     if (e.storageArea && e.storageArea !== localStorage) return
     const key = e.key
-    if (
-      key !== LAYOUT_STORAGE_KEY
-      && key !== BROWSER_PREFERENCES_STORAGE_KEY
-    ) {
+    if (typeof key !== 'string' || !CROSS_TAB_SYNC_STORAGE_KEYS.includes(key as any)) {
       return
     }
     if (typeof e.newValue !== 'string') return