diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt b/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
index 00fde8c..1cb639a 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/ClockulaApp.kt
@@ -87,9 +87,9 @@ class ClockulaApp : Application() {
             // run, leaving it paused at what it banked (M7 D17).
             stopwatchEngine.onBootCompleted()
             // Last and guarded, like every bedtime call on a shared path: a
-            // force stop clears its AlarmManager slot too, so the slot is
-            // re-armed here. The mode's own state is left as it is.
-            runCatching { bedtimeEngine.rearm() }
+            // force stop clears its AlarmManager slot too, and may have slept
+            // through a bedtime or wake-up, so both are caught up here.
+            runCatching { bedtimeEngine.resync() }
         }
 
         // Never completes on its own — it is the widgets' one refresh trigger
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/MainActivity.kt b/app/src/main/java/de/jeanlucmakiola/clockula/MainActivity.kt
index 958be6d..a817945 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/MainActivity.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/MainActivity.kt
@@ -16,6 +16,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.clockula.bedtime.BedtimeIntents
 import de.jeanlucmakiola.clockula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.clockula.interop.InteropIntents
 import de.jeanlucmakiola.clockula.ui.crash.CrashReportActivity
@@ -165,7 +166,8 @@ class MainActivity : ComponentActivity() {
             .getOrNull()
             ?.toList()
             .orEmpty()
-        return ShellNavigation.requestFor(intent.action, alarmId, alarmIds)
+        val forZenRule = runCatching { BedtimeIntents.ZEN_RULE_EXTRAS.any(intent::hasExtra) }.getOrDefault(false)
+        return ShellNavigation.requestFor(intent.action, alarmId, alarmIds, forZenRule)
     }
 
     override fun onResume() {
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/alarm/receiver/SystemEventReceiver.kt b/app/src/main/java/de/jeanlucmakiola/clockula/alarm/receiver/SystemEventReceiver.kt
index 09df3ff..05469f6 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/alarm/receiver/SystemEventReceiver.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/alarm/receiver/SystemEventReceiver.kt
@@ -101,11 +101,12 @@ class SystemEventReceiver : HiltBroadcastReceiver() {
                         MidnightRefresh.schedule(context)
                     }
                 }
+            } finally {
                 // Last, and on its own: every one of these events can move or
                 // clear the bedtime slot too, but nothing bedtime does may
-                // delay or break the alarm and timer passes above.
+                // delay or break the alarm and timer passes above, and a
+                // failure up there must not cost bedtime its pass either.
                 runCatching { bedtimeEngine.resync() }
-            } finally {
                 pendingResult.finish()
             }
         }
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngine.kt b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngine.kt
index 1fdbcb4..fac51ee 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngine.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngine.kt
@@ -8,6 +8,7 @@ import de.jeanlucmakiola.clockula.domain.time.ZoneProvider
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
+import kotlin.time.Instant
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -41,50 +42,41 @@ class BedtimeEngine @Inject constructor(
 
     /**
      * A change made on the bedtime screen: stored, then applied at once. The
-     * rule is rewritten from the new settings, and the mode is switched to
-     * what the new schedule says now, so turning bedtime on at 23:30 for a
-     * 23:00 bedtime starts it straight away.
+     * rule is rewritten when a field it carries changed, and the mode is
+     * switched to what the new schedule says now, so turning bedtime on at
+     * 23:30 for a 23:00 bedtime starts it straight away.
      */
     suspend fun update(transform: (BedtimeSettings) -> BedtimeSettings) = lock.withLock {
-        val updated = transform(settings.currentBedtime())
+        val previous = settings.currentBedtime()
+        val updated = transform(previous)
         settings.setBedtime(updated)
-        apply(updated, refreshRule = true)
+        apply(updated, refreshRule = previous.ruleFields() != updated.ruleFields(), force = true)
     }
 
     /**
-     * Everything that can invalidate the slot or the rule: a reboot, an app
-     * update, a clock or zone change, a backup restore, and Do Not Disturb
-     * access being granted or revoked.
+     * Everything that can invalidate the slot or the rule: app launch (a
+     * force stop clears the slot), a reboot, an app update, a clock or zone
+     * change, a backup restore, and Do Not Disturb access changing. The mode
+     * is only switched when the schedule crossed a boundary since Clockula
+     * last switched it, so a mode the user turned on or off by hand stays
+     * that way until the next bedtime or wake-up. [refreshRule] also rewrites
+     * the rule and re-asserts the mode's state.
      */
     suspend fun resync(refreshRule: Boolean = false) = lock.withLock {
-        apply(settings.currentBedtime(), refreshRule = refreshRule)
+        apply(settings.currentBedtime(), refreshRule = refreshRule, force = refreshRule)
     }
 
     /**
-     * App launch: re-arm the slot only. AlarmManager forgets it on a force
-     * stop, but the mode's state is left alone here — a launch is not a
-     * bedtime event, and a mode the user switched on or off by hand should
-     * stay that way until the next one.
-     */
-    suspend fun rearm() = lock.withLock {
-        schedule(settings.currentBedtime())
-    }
-
-    /**
-     * The slot arriving. A reminder fire posts the reminder and leaves the
-     * mode alone; any other fire switches the mode to what the schedule says
-     * now. Either way the next event is armed.
+     * The slot arriving: the mode follows any boundary crossed, a due
+     * reminder is posted, and the next event is armed. A reminder fire alone
+     * crosses no boundary, so it leaves the mode as it is.
      */
     suspend fun onSlotFired() = lock.withLock {
         val current = settings.currentBedtime()
         val now = wallClock.now()
-        val zone = zones.current()
-        val reminderFor = BedtimeSchedule.dueReminder(current, now, zone)
-        if (reminderFor != null) {
-            notifier.showReminder(reminderFor.start, current.reminderMinutes)
-            schedule(current)
-        } else {
-            apply(current, refreshRule = false)
+        apply(current, refreshRule = false, force = false, now = now)
+        BedtimeSchedule.dueReminder(current, now, zones.current())?.let { window ->
+            notifier.showReminder(window.start, current.reminderMinutes)
         }
     }
 
@@ -95,7 +87,17 @@ class BedtimeEngine @Inject constructor(
 
     fun ruleId(): String? = mode.ruleId()
 
-    private fun apply(current: BedtimeSettings, refreshRule: Boolean) {
+    /**
+     * One pass, over one reading of the clock: the mode's state and the next
+     * slot must agree about which side of a boundary "now" is on.
+     */
+    private suspend fun apply(
+        current: BedtimeSettings,
+        refreshRule: Boolean,
+        force: Boolean,
+        now: Instant = wallClock.now(),
+    ) {
+        val zone = zones.current()
         if (!current.enabled) {
             scheduler.cancel()
             notifier.cancelReminder()
@@ -103,20 +105,24 @@ class BedtimeEngine @Inject constructor(
             // is nothing Clockula may remove; revoking access in Settings
             // already removed the rule.
             if (mode.hasAccess()) mode.uninstall()
+            settings.setBedtimeAppliedActive(false)
             return
         }
-        val now = wallClock.now()
-        val active = BedtimeSchedule.activeWindow(current, now, zones.current()) != null
-        if (active) notifier.cancelReminder()
+        val active = BedtimeSchedule.activeWindow(current, now, zone) != null
+        // A reminder that no longer points at a coming bedtime (it started,
+        // or the schedule changed under it) is stale.
+        if (BedtimeSchedule.dueReminder(current, now, zone) == null) notifier.cancelReminder()
         if (mode.hasAccess()) {
             mode.install(current, refresh = refreshRule)
-            mode.setActive(active)
+            if (force || active != settings.bedtimeAppliedActive()) {
+                mode.setActive(active)
+                settings.setBedtimeAppliedActive(active)
+            }
         }
-        schedule(current)
-    }
-
-    private fun schedule(current: BedtimeSettings) {
-        val next = BedtimeSchedule.nextEvent(current, wallClock.now(), zones.current())
+        val next = BedtimeSchedule.nextEvent(current, now, zone)
         if (next == null) scheduler.cancel() else scheduler.schedule(next)
     }
+
+    /** What the system rule is built from; the reminder is not part of it. */
+    private fun BedtimeSettings.ruleFields() = listOf(enabled, bedtime, wakeTime, effects)
 }
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeIntents.kt b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeIntents.kt
index 4eb52a0..f9a2758 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeIntents.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/BedtimeIntents.kt
@@ -11,12 +11,17 @@ object BedtimeIntents {
     const val ACTION_SHOW_BEDTIME: String = "de.jeanlucmakiola.clockula.action.SHOW_BEDTIME"
 
     /**
-     * `NotificationManager.ACTION_AUTOMATIC_ZEN_RULE`: what Settings sends the
-     * rule's configuration activity (`MainActivity`) when the user taps
-     * "Clockula" on the mode's page. Spelled out so the shell's pure routing
-     * table needs no Android import.
+     * The extras Settings puts on the rule's configuration activity
+     * (`MainActivity`) when the user taps "Clockula" on the mode's page:
+     * `NotificationManager.EXTRA_AUTOMATIC_RULE_ID` and
+     * `ConditionProviderService.EXTRA_RULE_ID`. Settings sends no action with
+     * them, only the explicit component, so their presence is the signal.
+     * Spelled out so the shell's pure routing table needs no Android import.
      */
-    const val ACTION_AUTOMATIC_ZEN_RULE: String = "android.app.action.AUTOMATIC_ZEN_RULE"
+    val ZEN_RULE_EXTRAS: List<String> = listOf(
+        "android.app.extra.AUTOMATIC_RULE_ID",
+        "android.service.notification.extra.RULE_ID",
+    )
 
     /**
      * Apart from every alarm and timer request code, although the explicit
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeMode.kt b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeMode.kt
index ce71253..0319d06 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeMode.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeMode.kt
@@ -34,7 +34,7 @@ import javax.inject.Singleton
  * media, for a sleep sound) and leaves everything else to the device's own Do
  * Not Disturb defaults. A rule needs an owner service or a configuration
  * activity; [MainActivity] is the latter, and it opens the bedtime screen when
- * Settings sends `ACTION_AUTOMATIC_ZEN_RULE`. It is already exported, so no new
+ * Settings opens it for the rule. It is already exported, so no new
  * component is exposed for this.
  *
  * Nothing is stored about the rule. [NotificationManager.getAutomaticZenRules]
@@ -70,9 +70,14 @@ class AndroidBedtimeMode @Inject constructor(
             if (existing == null) {
                 manager.addAutomaticZenRule(rule(settings, enabled = true))
             } else if (refresh) {
-                // Keeps the user's own on/off switch for the rule in Settings: a
-                // change on Clockula's screen must not re-enable a rule they disabled.
-                manager.updateAutomaticZenRule(existing.key, rule(settings, enabled = existing.value.isEnabled))
+                // Keeps what the user set for the rule in Settings: its on/off
+                // switch (a change here must not re-enable a rule they
+                // disabled) and who may interrupt, which Android 10 to 14
+                // would otherwise overwrite. Android 15 keeps both itself.
+                manager.updateAutomaticZenRule(
+                    existing.key,
+                    rule(settings, enabled = existing.value.isEnabled, kept = existing.value.zenPolicy),
+                )
             }
         }
     }
@@ -104,13 +109,19 @@ class AndroidBedtimeMode @Inject constructor(
     private fun ownRules(): Map<String, AutomaticZenRule> =
         manager.automaticZenRules.filterValues { it.conditionId == conditionId }
 
-    private fun rule(settings: BedtimeSettings, enabled: Boolean): AutomaticZenRule {
+    /**
+     * [kept] is the existing rule's policy, reused as long as it lets alarms
+     * through: a user's edit in Settings survives, and an edit that blocked
+     * alarms is the one thing replaced.
+     */
+    private fun rule(settings: BedtimeSettings, enabled: Boolean, kept: ZenPolicy? = null): AutomaticZenRule {
         val name = context.getString(R.string.bedtime_mode_name)
         val configuration = ComponentName(context, MainActivity::class.java)
-        val policy = ZenPolicy.Builder()
-            .allowAlarms(true)
-            .allowMedia(true)
-            .build()
+        val policy = kept?.takeIf { it.priorityCategoryAlarms == ZenPolicy.STATE_ALLOW }
+            ?: ZenPolicy.Builder()
+                .allowAlarms(true)
+                .allowMedia(true)
+                .build()
         return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
             modeRule(name, configuration, policy, settings, enabled)
         } else {
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeScheduler.kt b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeScheduler.kt
index 11ba260..10c7c37 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeScheduler.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/android/AndroidBedtimeScheduler.kt
@@ -34,7 +34,9 @@ class AndroidBedtimeScheduler @Inject constructor(
         val exact = runCatching {
             manager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, millis, pendingIntent)
         }.isSuccess
-        if (!exact) manager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, millis, pendingIntent)
+        // Guarded too: bedtime losing its slot is survivable, a crash in the
+        // receiver's process is not.
+        if (!exact) runCatching { manager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, millis, pendingIntent) }
     }
 
     override fun cancel() = manager.cancel(slotPendingIntent())
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/receiver/BedtimeReceiver.kt b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/receiver/BedtimeReceiver.kt
index 2d6b448..1f6ad1f 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/receiver/BedtimeReceiver.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/bedtime/receiver/BedtimeReceiver.kt
@@ -36,10 +36,14 @@ class BedtimeReceiver : HiltBroadcastReceiver() {
         val pendingResult = goAsync()
         scope.launch {
             try {
-                when (action) {
-                    BedtimeIntents.ACTION_SLOT -> engine.onSlotFired()
-                    NotificationManager.ACTION_NOTIFICATION_POLICY_ACCESS_GRANTED_CHANGED ->
-                        engine.resync(refreshRule = true)
+                // Guarded: a platform refusal here must not crash the process,
+                // which is the process an alarm may be about to ring in.
+                runCatching {
+                    when (action) {
+                        BedtimeIntents.ACTION_SLOT -> engine.onSlotFired()
+                        NotificationManager.ACTION_NOTIFICATION_POLICY_ACCESS_GRANTED_CHANGED ->
+                            engine.resync(refreshRule = true)
+                    }
                 }
             } finally {
                 pendingResult.finish()
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupCodec.kt b/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupCodec.kt
index 3fd7069..e82852c 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupCodec.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupCodec.kt
@@ -154,7 +154,8 @@ object BackupCodec {
         enabled = enabled,
         bedtime = minutesToTime(bedtimeMinutes),
         wakeTime = minutesToTime(wakeMinutes),
-        days = RepeatDays.fromMask(days),
+        // The screen never lets the last night go; a file with none gets all.
+        days = RepeatDays.fromMask(days).takeIf { it.isRepeating } ?: RepeatDays.EVERY_DAY,
         reminderMinutes = reminderMinutes.coerceIn(BedtimeLimits.REMINDER_MINUTES),
         effects = BedtimeEffects(
             grayscale = grayscale,
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupDto.kt b/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupDto.kt
index b225f4a..f664ca4 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupDto.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupDto.kt
@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.clockula.data.backup
 
+import de.jeanlucmakiola.clockula.domain.bedtime.BedtimeSettings
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
@@ -87,13 +88,16 @@ data class SettingsDto(
  */
 @Serializable
 data class BedtimeDto(
-    val enabled: Boolean = false,
-    @SerialName("bedtime_minutes") val bedtimeMinutes: Int = 22 * 60 + 30,
-    @SerialName("wake_minutes") val wakeMinutes: Int = 7 * 60,
-    val days: Int = 0b111_1111,
-    @SerialName("reminder_minutes") val reminderMinutes: Int = 0,
-    val grayscale: Boolean = true,
-    @SerialName("dim_wallpaper") val dimWallpaper: Boolean = true,
-    @SerialName("dark_theme") val darkTheme: Boolean = true,
-    @SerialName("hide_always_on_display") val hideAlwaysOnDisplay: Boolean = false,
+    val enabled: Boolean = DEFAULT_BEDTIME.enabled,
+    @SerialName("bedtime_minutes") val bedtimeMinutes: Int = DEFAULT_BEDTIME.bedtime.minutesOfDay,
+    @SerialName("wake_minutes") val wakeMinutes: Int = DEFAULT_BEDTIME.wakeTime.minutesOfDay,
+    val days: Int = DEFAULT_BEDTIME.days.mask,
+    @SerialName("reminder_minutes") val reminderMinutes: Int = DEFAULT_BEDTIME.reminderMinutes,
+    val grayscale: Boolean = DEFAULT_BEDTIME.effects.grayscale,
+    @SerialName("dim_wallpaper") val dimWallpaper: Boolean = DEFAULT_BEDTIME.effects.dimWallpaper,
+    @SerialName("dark_theme") val darkTheme: Boolean = DEFAULT_BEDTIME.effects.darkTheme,
+    @SerialName("hide_always_on_display") val hideAlwaysOnDisplay: Boolean = DEFAULT_BEDTIME.effects.hideAlwaysOnDisplay,
 )
+
+/** A missing field restores what a fresh install has. */
+private val DEFAULT_BEDTIME = BedtimeSettings()
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/BedtimePrefs.kt b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/BedtimePrefs.kt
index ab1704c..68810ef 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/BedtimePrefs.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/BedtimePrefs.kt
@@ -43,6 +43,14 @@ object BedtimePrefs {
     val hideAlwaysOnDisplay: Pref<Boolean> =
         booleanPref("bedtime_effect_hide_aod", DEFAULT.effects.hideAlwaysOnDisplay)
 
+    /**
+     * Whether Clockula last switched the mode on or off: device state, not
+     * configuration, so it is not in the JSON backup. It lets a pass switch
+     * the mode only when the schedule crossed a boundary since, and leave a
+     * mode the user switched by hand alone otherwise.
+     */
+    val appliedActive: Pref<Boolean> = booleanPref("bedtime_applied_active", false)
+
     /** Minutes since midnight on disk, clamped into a day both ways. */
     private fun Pref<Int>.asTimeOfDay(): Pref<TimeOfDay> = map(
         decode = { minutes ->
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
index b802eca..a85904e 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/data/prefs/SettingsPrefs.kt
@@ -178,6 +178,10 @@ class SettingsPrefs @Inject constructor(private val store: PrefStore) {
         store.edit { prefs -> prefs.putBedtime(settings) }
     }
 
+    suspend fun bedtimeAppliedActive(): Boolean = store.get(BedtimePrefs.appliedActive)
+
+    suspend fun setBedtimeAppliedActive(active: Boolean) = store.set(BedtimePrefs.appliedActive, active)
+
     private fun MutablePreferences.putBedtime(settings: BedtimeSettings) {
         this[BedtimePrefs.enabled] = settings.enabled
         this[BedtimePrefs.bedtime] = settings.bedtime
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/ui/bedtime/BedtimeViewModel.kt b/app/src/main/java/de/jeanlucmakiola/clockula/ui/bedtime/BedtimeViewModel.kt
index d05c397..a50eddc 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/ui/bedtime/BedtimeViewModel.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/ui/bedtime/BedtimeViewModel.kt
@@ -48,7 +48,7 @@ class BedtimeViewModel @Inject internal constructor(
         val changed = granted != access.value
         access.value = granted
         viewModelScope.launch {
-            if (changed) engine.resync(refreshRule = true)
+            if (changed) runCatching { engine.resync(refreshRule = true) }
             ruleId.value = engine.ruleId()
         }
     }
@@ -80,7 +80,7 @@ class BedtimeViewModel @Inject internal constructor(
 
     private fun update(transform: (BedtimeSettings) -> BedtimeSettings) {
         viewModelScope.launch {
-            engine.update(transform)
+            runCatching { engine.update(transform) }
             ruleId.value = engine.ruleId()
         }
     }
diff --git a/app/src/main/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigation.kt b/app/src/main/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigation.kt
index b0bb5bd..13cce4b 100644
--- a/app/src/main/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigation.kt
+++ b/app/src/main/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigation.kt
@@ -150,9 +150,16 @@ object ShellNavigation {
      * missing or non-positive alarm id, or an empty id list, falls back to the
      * Alarms tab (M9 D23).
      */
-    fun requestFor(action: String?, alarmId: Long?, alarmIds: List<Long>): ShellRequest? =
+    fun requestFor(
+        action: String?,
+        alarmId: Long?,
+        alarmIds: List<Long>,
+        forZenRule: Boolean = false,
+    ): ShellRequest? =
         when (action) {
-            null -> null
+            // Settings opening the bedtime rule's configuration activity: an
+            // explicit component, a rule id extra, and no action (issue #1).
+            null -> if (forZenRule) ShellRequest.OpenBedtime else null
             InteropIntents.ACTION_OPEN_ALARM_EDITOR ->
                 if (alarmId != null && alarmId > 0L) {
                     ShellRequest.OpenAlarmEditor(alarmId)
@@ -160,9 +167,7 @@ object ShellNavigation {
                     ShellRequest.OpenTab(ClockulaDestination.ALARMS)
                 }
             InteropIntents.ACTION_COMPOSE_TIMER -> ShellRequest.ComposeTimer
-            BedtimeIntents.ACTION_SHOW_BEDTIME,
-            BedtimeIntents.ACTION_AUTOMATIC_ZEN_RULE,
-            -> ShellRequest.OpenBedtime
+            BedtimeIntents.ACTION_SHOW_BEDTIME -> ShellRequest.OpenBedtime
             InteropIntents.ACTION_CHOOSE_ALARM_TO_DISMISS ->
                 if (alarmIds.isEmpty()) {
                     ShellRequest.OpenTab(ClockulaDestination.ALARMS)
diff --git a/app/src/test/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngineTest.kt b/app/src/test/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngineTest.kt
index d961b20..aeba63b 100644
--- a/app/src/test/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngineTest.kt
+++ b/app/src/test/java/de/jeanlucmakiola/clockula/bedtime/BedtimeEngineTest.kt
@@ -163,18 +163,58 @@ class BedtimeEngineTest {
     }
 
     @Test
-    fun `rearming touches the slot and not the mode`(@TempDir tempDir: Path) = runTest {
+    fun `a resync with no boundary crossed leaves a hand-switched mode alone`(@TempDir tempDir: Path) = runTest {
         val h = harness(tempDir)
         h.engine.update(nightly)
+        // Switched on by hand in the afternoon, then the slot lost to a force stop.
         h.mode.on = true
         h.scheduler.cancel()
 
-        h.engine.rearm()
+        h.engine.resync()
 
         assertThat(h.mode.on).isTrue()
         assertThat(h.scheduler.armedAt).isEqualTo(offsetInstant("2026-06-10T23:00+02:00"))
     }
 
+    @Test
+    fun `a reminder fire that also ends a window turns the mode off`(@TempDir tempDir: Path) = runTest {
+        // A 23.5-hour window whose end falls inside the next one's reminder lead.
+        val h = harness(tempDir, now = instantAt(BERLIN, "2026-06-10T08:00"))
+        h.engine.update {
+            it.copy(enabled = true, bedtime = TimeOfDay(7, 30), wakeTime = TimeOfDay(7, 0), reminderMinutes = 30)
+        }
+        assertThat(h.mode.on).isTrue()
+
+        h.wallClock.instant = instantAt(BERLIN, "2026-06-11T07:00")
+        h.engine.onSlotFired()
+
+        assertThat(h.mode.on).isFalse()
+        assertThat(h.notifier.reminders).hasSize(1)
+    }
+
+    @Test
+    fun `a reminder the schedule moved away from is withdrawn`(@TempDir tempDir: Path) = runTest {
+        val h = harness(tempDir)
+        h.engine.update { nightly(it).copy(reminderMinutes = 30) }
+        h.wallClock.instant = instantAt(BERLIN, "2026-06-10T22:30")
+        h.engine.onSlotFired()
+        assertThat(h.notifier.showing).isTrue()
+
+        h.engine.update { it.copy(bedtime = TimeOfDay(23, 59)) }
+
+        assertThat(h.notifier.showing).isFalse()
+    }
+
+    @Test
+    fun `changing only the reminder does not rewrite the rule`(@TempDir tempDir: Path) = runTest {
+        val h = harness(tempDir)
+        h.engine.update(nightly)
+
+        h.engine.update { it.copy(reminderMinutes = 45) }
+
+        assertThat(h.mode.refreshes).isEqualTo(0)
+    }
+
     @Test
     fun `a missed wake-up fire is caught up by the next resync`(@TempDir tempDir: Path) = runTest {
         val h = harness(tempDir, now = instantAt(BERLIN, "2026-06-10T23:30"))
diff --git a/app/src/test/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigationInteropTest.kt b/app/src/test/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigationInteropTest.kt
index cbe63e3..bc3ce5c 100644
--- a/app/src/test/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigationInteropTest.kt
+++ b/app/src/test/java/de/jeanlucmakiola/clockula/ui/shell/ShellNavigationInteropTest.kt
@@ -128,7 +128,10 @@ class ShellNavigationInteropTest {
     fun `the bedtime reminder and the mode's settings page both open the bedtime screen`() {
         assertThat(ShellNavigation.requestFor(BedtimeIntents.ACTION_SHOW_BEDTIME, null, emptyList()))
             .isEqualTo(ShellRequest.OpenBedtime)
-        assertThat(ShellNavigation.requestFor(BedtimeIntents.ACTION_AUTOMATIC_ZEN_RULE, null, emptyList()))
+        // Settings opens the rule's configuration activity with no action,
+        // only the component and the rule id.
+        assertThat(ShellNavigation.requestFor(null, null, emptyList(), forZenRule = true))
             .isEqualTo(ShellRequest.OpenBedtime)
+        assertThat(ShellNavigation.requestFor(null, null, emptyList())).isNull()
     }
 }
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index 363dc39..10c3e25 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -602,7 +602,7 @@ Four slices:
 | Stopwatch run record (M2) | `stopwatch_state`, `stopwatch_started_elapsed_millis`, `stopwatch_accumulated_millis`, `stopwatch_last_lap_cumulative_millis` (M7 is the first caller of the last, for the in-progress lap's split) | `StopwatchPrefs`, behind `StopwatchStateStore` |
 | System facts (M3) | `last_boot_id` | `SystemPrefs`, behind `BootStateStore`, the persisted half of the reboot gate |
 | Timers (M6) | `timer_presets`, `timer_ring_sounding_since_millis` | `TimerPrefs`: the presets surfaced as `SettingsPrefs.timerPresets`, the ring session's anchor behind `TimerRingStateStore` |
-| Bedtime (issue #1) | `bedtime_enabled`, `bedtime_start_minutes`, `bedtime_wake_minutes`, `bedtime_days`, `bedtime_reminder_minutes`, `bedtime_effect_grayscale`, `bedtime_effect_dim_wallpaper`, `bedtime_effect_dark_theme`, `bedtime_effect_hide_aod` | `BedtimePrefs`, surfaced as `SettingsPrefs.bedtime: Flow<BedtimeSettings>` and written as one record by `BedtimeEngine` only. Times clamp into a day, the reminder into 0–120 minutes, the days through `RepeatDays.fromMask`. The system rule's id is **not** stored (§18) |
+| Bedtime (issue #1) | `bedtime_enabled`, `bedtime_start_minutes`, `bedtime_wake_minutes`, `bedtime_days`, `bedtime_reminder_minutes`, `bedtime_effect_grayscale`, `bedtime_effect_dim_wallpaper`, `bedtime_effect_dark_theme`, `bedtime_effect_hide_aod`, `bedtime_applied_active` | `BedtimePrefs`, surfaced as `SettingsPrefs.bedtime: Flow<BedtimeSettings>` and written as one record by `BedtimeEngine` only. Times clamp into a day, the reminder into 0–120 minutes, the days through `RepeatDays.fromMask`. The system rule's id is **not** stored (§18) |
 
 The stopwatch's *run* is a single record, so it lives in DataStore rather than
 as a one-row table (`PLAN.md` §5); its *laps* are a list, so they live in Room.
@@ -2726,9 +2726,11 @@ automatic zen rule of its own:
 
 A rule needs an owner `ConditionProviderService` or a configuration activity.
 Clockula uses `MainActivity` as the configuration activity: it is already
-exported, so no new component is exposed, and when Settings sends it
-`NotificationManager.ACTION_AUTOMATIC_ZEN_RULE` the shell opens the bedtime
-screen (`ShellRequest.OpenBedtime`). There is no condition provider service:
+exported, so no new component is exposed. Settings opens it with the explicit
+component, the rule id in `NotificationManager.EXTRA_AUTOMATIC_RULE_ID` /
+`ConditionProviderService.EXTRA_RULE_ID`, and **no action**, so the presence of
+either extra is what makes the shell open the bedtime screen
+(`ShellRequest.OpenBedtime`). There is no condition provider service:
 Clockula reports the rule's state itself with `setAutomaticZenRuleState`.
 
 The two modes coexist. A Pixel user who also uses Wellbeing's Bedtime sees two
@@ -2740,9 +2742,12 @@ The rule's `ZenPolicy` sets exactly two things, `allowAlarms(true)` and
 `allowMedia(true)` (a sleep sound keeps playing), and leaves every other field
 unset, so calls, messages and the rest follow the device's own Do Not Disturb
 defaults. Clockula's alarms and timers play with `USAGE_ALARM`, so the
-exemption applies. A user who later edits the mode in Settings and blocks alarms
-there has made that choice in the system's own UI; Android 15 keeps a user's
-edits over an app's updates, and Clockula does not fight them. The self-check
+exemption applies. The rule is only rewritten when a field it carries changes
+(the times, the effects, the switch; not the reminder), and a rewrite reuses
+the rule's existing policy as long as that still allows alarms, so a user's
+"who may interrupt" edits in Settings survive on Android 10 to 14 as well
+(Android 15 keeps a user's edits over an app's updates by itself). An edit
+that blocked alarms is the one thing a rewrite puts back. The self-check
 (M10's `SelfCheck`) still reports total silence as a problem whatever caused it.
 
 ### The engine
@@ -2771,14 +2776,27 @@ reminder and the next window's start.
 
 | Entry point | Called from | What it does |
 |---|---|---|
-| `update(transform)` | the bedtime screen | stores the settings, rewrites the rule from them, sets the mode to what the schedule says now (on at 23:30 for a 23:00 bedtime starts it at once), arms the slot. Off removes the rule, which ends the mode, cancels the slot and clears the reminder |
-| `onSlotFired()` | `BedtimeReceiver` | a reminder fire posts the reminder and **leaves the mode alone**; any other fire sets the mode on or off. Then arms the next event |
-| `resync(refreshRule)` | `SystemEventReceiver` (boot, app update, clock or zone change, exact-alarm permission), Do Not Disturb access changing, a backup restore | creates the rule if it is missing, sets the mode, arms the slot |
-| `rearm()` | `ClockulaApp.onCreate` | arms the slot only. A force stop clears it, but a launch is not a bedtime event, so a mode the user switched by hand stays as it is |
+| `update(transform)` | the bedtime screen | stores the settings, rewrites the rule if a field it carries changed, sets the mode to what the schedule says now (on at 23:30 for a 23:00 bedtime starts it at once), arms the slot. Off removes the rule, which ends the mode, cancels the slot and clears the reminder |
+| `onSlotFired()` | `BedtimeReceiver` | follows any boundary crossed, posts a due reminder, arms the next event. A reminder fire alone crosses no boundary, so it leaves a mode switched on by hand alone |
+| `resync()` | `ClockulaApp.onCreate` (a force stop clears the slot), `SystemEventReceiver` (boot, app update, clock or zone change, exact-alarm permission) | creates the rule if it is missing, follows any boundary crossed, arms the slot |
+| `resync(refreshRule = true)` | Do Not Disturb access changing (the screen's `ON_RESUME` check and the broadcast), a backup restore | the same, but also rewrites the rule and re-asserts the mode's state |
+
+"Follows any boundary crossed" is the one rule that lets a hand-switched mode
+coexist with a schedule. The last state Clockula set is persisted
+(`bedtime_applied_active`, device state, not in the JSON backup), and a pass
+that is not an edit switches the mode only when the schedule now says
+something different. A launch in the afternoon leaves a mode the user turned
+on alone; a launch after a force stop that slept through the wake-up time
+turns it off. Each pass reads the clock **once**, so the mode's state and the
+next slot always agree about which side of a boundary "now" is on. A posted
+reminder is withdrawn by any pass once no coming bedtime is due within its
+lead, so moving the schedule away from it does not leave a stale one.
 
 Every bedtime call on a shared path runs **after** the alarm, timer and
-stopwatch passes and inside `runCatching`, so nothing bedtime does can delay
-or break them.
+stopwatch passes and inside `runCatching` (in `SystemEventReceiver`, in its
+`finally`, so a failure up there does not cost bedtime its pass either), so
+nothing bedtime does can delay or break them. `BedtimeReceiver` and the
+screen guard their calls too.
 
 ### No stored rule id
 
@@ -2806,7 +2824,8 @@ Turning bedtime off removes the rule cleanly.
 ### Backup
 
 The settings travel in the backup's `settings.bedtime` object
-(`docs/BACKUP.md`); a file from before issue #1 restores bedtime as off.
+(`docs/BACKUP.md`); a file from before issue #1 restores bedtime as off, and
+one with no nights at all restores every night.
 `BackupEngine.import` resyncs the engine after the replace, or after rolling
 it back.
 
diff --git a/docs/BACKUP.md b/docs/BACKUP.md
index e58eb1f..6a26075 100644
--- a/docs/BACKUP.md
+++ b/docs/BACKUP.md
@@ -157,7 +157,7 @@ since local midnight, `days` is the same 7-bit mask as an alarm's
 reminder. A file without `bedtime` (any file written before it existed)
 restores bedtime as off with the default schedule. Like the other settings it
 is clamped rather than rejected: times into a day, the reminder into 0–120
-minutes. The id of the Do Not Disturb rule a device created is not part of it;
+minutes, and a `days` of 0 (which the screen never allows) into every night. The id of the Do Not Disturb rule a device created is not part of it;
 the importing device creates its own (`docs/ARCHITECTURE.md` §18).
 
 Field names mirror `ClockPrefs`'/`SettingsPrefs`' own on-disk keys. Older