diff --git a/apps/desktop/src/store/updates.test.ts b/apps/desktop/src/store/updates.test.ts
index 913e4fb11ee..bb74cd650c1 100644
--- a/apps/desktop/src/store/updates.test.ts
+++ b/apps/desktop/src/store/updates.test.ts
@@ -41,7 +41,7 @@ vi.mock('@/hermes', () => ({
   getActionStatus: (...args: unknown[]) => getActionStatusSpy(...args)
 }))
 
-const { maybeNotifyUpdateAvailable, checkBackendUpdates, $backendUpdateStatus, applyBackendUpdate, $backendUpdateApply } = await import('./updates')
+const { maybeNotifyUpdateAvailable, checkBackendUpdates, $backendUpdateStatus, applyBackendUpdate, $backendUpdateApply, reportBackendContract } = await import('./updates')
 const { setConnection } = await import('./session')
 
 const status = (over: Partial<DesktopUpdateStatus> = {}): DesktopUpdateStatus => ({
@@ -95,6 +95,61 @@ describe('maybeNotifyUpdateAvailable', () => {
   })
 })
 
+describe('reportBackendContract', () => {
+  beforeEach(() => {
+    storage.clear()
+    notifySpy.mockClear()
+    dismissSpy.mockClear()
+    vi.useRealTimers()
+  })
+
+  it('dismisses the toast when the backend meets the contract', () => {
+    reportBackendContract(2)
+    expect(dismissSpy).toHaveBeenCalledWith('backend-contract-skew')
+    expect(notifySpy).not.toHaveBeenCalled()
+  })
+
+  it('warns when the backend is behind (or reports no contract)', () => {
+    reportBackendContract(undefined)
+    expect(notifySpy).toHaveBeenCalledTimes(1)
+    reportBackendContract(1)
+    expect(notifySpy).toHaveBeenCalledTimes(2)
+  })
+
+  it('stays quiet on later session opens once the user closed it', () => {
+    reportBackendContract(1)
+    lastToast().onDismiss() // user closes it → cooldown starts
+    notifySpy.mockClear()
+
+    // Opening another pre-existing session re-runs the check within cooldown.
+    reportBackendContract(1)
+    expect(notifySpy).not.toHaveBeenCalled()
+  })
+
+  it('reminds again after the cooldown elapses', () => {
+    vi.useFakeTimers()
+    vi.setSystemTime(0)
+
+    reportBackendContract(1)
+    lastToast().onDismiss()
+    notifySpy.mockClear()
+
+    vi.setSystemTime(25 * 60 * 60 * 1000) // > 24h cooldown
+    reportBackendContract(1)
+    expect(notifySpy).toHaveBeenCalledTimes(1)
+  })
+
+  it('clears the snooze once the backend catches up, so a regression warns again', () => {
+    reportBackendContract(1)
+    lastToast().onDismiss()
+    notifySpy.mockClear()
+
+    reportBackendContract(2) // backend updated → satisfied, snooze cleared
+    reportBackendContract(1) // a later regression must warn immediately
+    expect(notifySpy).toHaveBeenCalledTimes(1)
+  })
+})
+
 describe('checkBackendUpdates', () => {
   beforeEach(() => {
     storage.clear()
diff --git a/apps/desktop/src/store/updates.ts b/apps/desktop/src/store/updates.ts
index 8b838d4aacd..b9338314e70 100644
--- a/apps/desktop/src/store/updates.ts
+++ b/apps/desktop/src/store/updates.ts
@@ -91,26 +91,60 @@ function isUpdateToastSnoozed(): boolean {
 // v2: requires the file.attach RPC (remote-gateway non-image file upload).
 const REQUIRED_BACKEND_CONTRACT = 2
 const SKEW_TOAST_ID = 'backend-contract-skew'
+// The contract check runs on every session.resume (applyRuntimeInfo), so
+// without a snooze the warning re-popped on every thread the user opened, even
+// right after they closed it. Mirror the update toast: persist a cooldown when
+// the user dismisses it. It still reminds again after the window if the backend
+// is still behind, and clears immediately once the backend catches up.
+const SKEW_TOAST_SNOOZE_KEY = 'hermes:backend-skew-toast-snooze-until'
+const SKEW_TOAST_COOLDOWN_MS = 24 * 60 * 60 * 1000
+
+function snoozeSkewToast(): void {
+  persistString(SKEW_TOAST_SNOOZE_KEY, String(Date.now() + SKEW_TOAST_COOLDOWN_MS))
+}
+
+function isSkewToastSnoozed(): boolean {
+  const until = Number(storedString(SKEW_TOAST_SNOOZE_KEY) || 0)
+
+  return Number.isFinite(until) && Date.now() < until
+}
 
 /**
  * Guard against a desktop GUI talking to a backend that predates its contract
  * (e.g. a bb/gui-built app pointed at a `main` checkout). Rather than failing
- * cryptically downstream, surface a persistent warning with a one-click align
- * that runs the normal update flow (which self-heals to the right branch).
+ * cryptically downstream, surface a warning with a one-click align that runs
+ * the normal update flow (which self-heals to the right branch).
+ *
+ * Runs on every session open; closing the toast snoozes it for a cooldown so it
+ * doesn't nag on every thread switch.
  */
 export function reportBackendContract(contract: number | undefined): void {
   if ((contract ?? 0) >= REQUIRED_BACKEND_CONTRACT) {
     dismissNotification(SKEW_TOAST_ID)
+    // Backend caught up — forget any prior snooze so a future regression warns
+    // immediately rather than staying silent for the rest of the window.
+    persistString(SKEW_TOAST_SNOOZE_KEY, null)
 
     return
   }
 
+  if (isSkewToastSnoozed()) {
+    return
+  }
+
   notify({
-    action: { label: translateNow('notifications.updateHermes'), onClick: () => void applyBackendUpdate() },
+    action: {
+      label: translateNow('notifications.updateHermes'),
+      onClick: () => {
+        snoozeSkewToast()
+        void applyBackendUpdate()
+      }
+    },
     durationMs: 0,
     id: SKEW_TOAST_ID,
     kind: 'warning',
     message: translateNow('notifications.backendOutOfDateMessage'),
+    onDismiss: () => snoozeSkewToast(),
     title: translateNow('notifications.backendOutOfDateTitle')
   })
 }