diff --git a/android/README.md b/android/README.md
index 77c590a..b89ad1b 100644
--- a/android/README.md
+++ b/android/README.md
@@ -8,7 +8,7 @@
 - 自动注册和已认证的版本信息更新，无注册码输入页。
 - Android Keystore AES-GCM 加密保存 Device Token，界面和日志不显示明文。
 - 前台服务、15 秒心跳、网络恢复触发重连。
-- Agent 0.3.0 的状态、采集、采购、设置四 Tab 外壳；默认进入状态页。
+- Agent 0.3.1 的状态、采集、采购、设置四 Tab 外壳；默认进入状态页。
 - 状态页区分无障碍未开启、系统已开启但服务未绑定、已绑定就绪三态。
 - 设置页可测试服务器连接、保存服务器地址和设备名称并重新连接；任务执行中禁止修改。
 - 设置页只显示 Device Token 是否配置，不显示 Token 明文；采集和采购 Tab 在 #90 接入当前设备任务历史。
@@ -18,6 +18,8 @@
 
 设备执行任务时，状态页显示当前任务，设置页会禁用服务器地址、设备名称、测试和保存操作。返回系统无障碍设置后，状态页和设置页会自动刷新真实就绪状态。
 
+任务结果成功提交（采购结果也可以先安全写入本地 Outbox）后，Agent 进入 15 秒冷却。它沿用现有任务轮询依次确认采购、采集队列都为空，并确认用户没有离开本次自动化打开的 PDD/浏览器页面，才返回 Agent 状态页。新任务、网络异常、待恢复的不可逆采购边界或前台应用变化都会取消自动返回。任务执行和冷却期间有界保持亮屏，结束后释放；不会自动解锁 PIN、图案或密码。
+
 ## T05 真机验证记录
 
 - 一加 PKG110 / Android 16：首次注册、15 秒心跳、前台通知和在线空闲状态已验证。
diff --git a/android/app/build.gradle.kts b/android/app/build.gradle.kts
index ddff439..00998c9 100644
--- a/android/app/build.gradle.kts
+++ b/android/app/build.gradle.kts
@@ -11,8 +11,8 @@ android {
         applicationId = "cn.ilapage.goauto.agent"
         minSdk = 23
         targetSdk = 34
-        versionCode = 3
-        versionName = "0.3.0"
+        versionCode = 4
+        versionName = "0.3.1"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
 
diff --git a/android/app/src/main/java/cn/ilapage/goauto/agent/MainActivity.kt b/android/app/src/main/java/cn/ilapage/goauto/agent/MainActivity.kt
index 3a6c5a0..29d9908 100644
--- a/android/app/src/main/java/cn/ilapage/goauto/agent/MainActivity.kt
+++ b/android/app/src/main/java/cn/ilapage/goauto/agent/MainActivity.kt
@@ -5,6 +5,7 @@ import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
 import android.view.Menu
+import android.view.WindowManager
 import android.widget.FrameLayout
 import android.widget.LinearLayout
 import androidx.appcompat.app.AppCompatActivity
@@ -18,15 +19,44 @@ import com.google.android.material.bottomnavigation.BottomNavigationView
 
 class MainActivity : AppCompatActivity() {
     private var selectedTab = TAB_STATUS
+    private lateinit var navigation: BottomNavigationView
+    private val screenPolicyHandler = android.os.Handler(android.os.Looper.getMainLooper())
+    private val screenPolicyRefresh = object : Runnable {
+        override fun run() {
+            applyScreenPolicy()
+            screenPolicyHandler.postDelayed(this, SCREEN_POLICY_REFRESH_MILLIS)
+        }
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        selectedTab = savedInstanceState?.getInt(STATE_SELECTED_TAB) ?: TAB_STATUS
+        selectedTab = if (intent.getBooleanExtra(EXTRA_SHOW_STATUS, false)) {
+            TAB_STATUS
+        } else {
+            savedInstanceState?.getInt(STATE_SELECTED_TAB) ?: TAB_STATUS
+        }
         setContentView(buildContent())
         requestNotificationPermission()
         if (AgentSettingsStore(this).serverUrl().isNotBlank()) AgentForegroundService.start(this)
     }
 
+    override fun onNewIntent(intent: android.content.Intent) {
+        super.onNewIntent(intent)
+        setIntent(intent)
+        if (intent.getBooleanExtra(EXTRA_SHOW_STATUS, false)) navigation.selectedItemId = TAB_STATUS
+    }
+
+    override fun onResume() {
+        super.onResume()
+        screenPolicyHandler.removeCallbacks(screenPolicyRefresh)
+        screenPolicyHandler.post(screenPolicyRefresh)
+    }
+
+    override fun onPause() {
+        screenPolicyHandler.removeCallbacks(screenPolicyRefresh)
+        super.onPause()
+    }
+
     override fun onSaveInstanceState(outState: Bundle) {
         outState.putInt(STATE_SELECTED_TAB, selectedTab)
         super.onSaveInstanceState(outState)
@@ -43,7 +73,7 @@ class MainActivity : AppCompatActivity() {
             0,
             1f,
         ))
-        val navigation = BottomNavigationView(this).apply {
+        navigation = BottomNavigationView(this).apply {
             setBackgroundColor(getColor(R.color.agent_surface))
             itemIconTintList = getColorStateList(R.color.agent_navigation_item)
             itemTextColor = getColorStateList(R.color.agent_navigation_item)
@@ -94,11 +124,22 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    private companion object {
+    private fun applyScreenPolicy() {
+        val keepScreenOn = cn.ilapage.goauto.agent.service.AgentStateStore(this).read().keepScreenOn
+        if (keepScreenOn) {
+            window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+        } else {
+            window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+        }
+    }
+
+    companion object {
+        const val EXTRA_SHOW_STATUS = "cn.ilapage.goauto.agent.SHOW_STATUS"
+        private const val SCREEN_POLICY_REFRESH_MILLIS = 1_000L
         const val TAB_STATUS = 1
-        const val TAB_COLLECTION = 2
-        const val TAB_PURCHASE = 3
-        const val TAB_SETTINGS = 4
-        const val STATE_SELECTED_TAB = "selected_tab"
+        private const val TAB_COLLECTION = 2
+        private const val TAB_PURCHASE = 3
+        private const val TAB_SETTINGS = 4
+        private const val STATE_SELECTED_TAB = "selected_tab"
     }
 }
diff --git a/android/app/src/main/java/cn/ilapage/goauto/agent/automation/GoAutoAccessibilityService.kt b/android/app/src/main/java/cn/ilapage/goauto/agent/automation/GoAutoAccessibilityService.kt
index e68a139..ae37247 100644
--- a/android/app/src/main/java/cn/ilapage/goauto/agent/automation/GoAutoAccessibilityService.kt
+++ b/android/app/src/main/java/cn/ilapage/goauto/agent/automation/GoAutoAccessibilityService.kt
@@ -17,8 +17,11 @@ import android.view.accessibility.AccessibilityNodeInfo
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicLong
 
 class GoAutoAccessibilityService : AccessibilityService(), UiDriver, PddCollectorDriver, PurchaseUiDriver {
+    private val foregroundRevision = AtomicLong(0L)
+    @Volatile private var lastForegroundPackage: String? = null
     private val activityTracker by lazy {
         ActivityEvidenceTracker { packageName, className -> isDeclaredActivity(packageName, className) }
     }
@@ -34,7 +37,12 @@ class GoAutoAccessibilityService : AccessibilityService(), UiDriver, PddCollecto
 
     override fun onAccessibilityEvent(event: AccessibilityEvent?) {
         if (event?.eventType == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED) {
-            activityTracker.observe(event.packageName?.toString(), event.className?.toString())
+            val packageName = event.packageName?.toString()
+            if (packageName != null && packageName != lastForegroundPackage) {
+                lastForegroundPackage = packageName
+                foregroundRevision.incrementAndGet()
+            }
+            activityTracker.observe(packageName, event.className?.toString())
         }
     }
     override fun onInterrupt() = Unit
@@ -47,6 +55,18 @@ class GoAutoAccessibilityService : AccessibilityService(), UiDriver, PddCollecto
     override fun currentPackage(): String? = rootInActiveWindow?.packageName?.toString()
     override fun currentActivity(): String? = activityTracker.current()
 
+    fun currentForegroundRevision(): Long = foregroundRevision.get()
+
+    fun openAgentStatus(): Boolean = runCatching {
+        startActivity(
+            android.content.Intent(this, cn.ilapage.goauto.agent.MainActivity::class.java).apply {
+                addFlags(android.content.Intent.FLAG_ACTIVITY_NEW_TASK or android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP or android.content.Intent.FLAG_ACTIVITY_SINGLE_TOP)
+                putExtra(cn.ilapage.goauto.agent.MainActivity.EXTRA_SHOW_STATUS, true)
+            },
+        )
+        true
+    }.getOrDefault(false)
+
     override fun visibleTexts(): List<String> {
         val root = rootInActiveWindow ?: return emptyList()
         val texts = mutableListOf<String>()
diff --git a/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentForegroundService.kt b/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentForegroundService.kt
index f1b90ad..d1d9716 100644
--- a/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentForegroundService.kt
+++ b/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentForegroundService.kt
@@ -15,6 +15,7 @@ import android.net.NetworkRequest
 import android.os.Build
 import android.os.IBinder
 import android.os.PowerManager
+import android.os.SystemClock
 import android.util.Log
 import cn.ilapage.goauto.agent.BuildConfig
 import cn.ilapage.goauto.agent.MainActivity
@@ -63,6 +64,10 @@ class AgentForegroundService : Service() {
     private val runningTaskId = AtomicReference<Long?>(null)
     private val working = AtomicBoolean(false)
     private val registeredThisProcess = AtomicBoolean(false)
+    private val taskWakeActive = AtomicBoolean(false)
+    private val idleReturn = IdleReturnCoordinator()
+    private var taskWakeLock: PowerManager.WakeLock? = null
+    private var cooldownWakeLock: PowerManager.WakeLock? = null
     private lateinit var identityStore: SecureDeviceStore
     private lateinit var settingsStore: AgentSettingsStore
     private lateinit var stateStore: AgentStateStore
@@ -80,6 +85,8 @@ class AgentForegroundService : Service() {
         identityStore = SecureDeviceStore(this)
         settingsStore = AgentSettingsStore(this)
         stateStore = AgentStateStore(this)
+        // Wake locks and cooldown tickets are process-local. Never restore a stale UI flag.
+        stateStore.setKeepScreenOn(false)
         purchaseStore = PurchaseTaskStore(this)
         val restoredPurchaseTaskId = purchaseStore.activeTaskId()
         runningTaskId.set(restoredPurchaseTaskId)
@@ -100,6 +107,8 @@ class AgentForegroundService : Service() {
 
     override fun onDestroy() {
         runCatching { connectivityManager.unregisterNetworkCallback(networkCallback) }
+        cancelIdleReturn("服务已停止")
+        releaseTaskWakeLock()
         executor.shutdownNow()
         taskExecutor.shutdownNow()
         purchaseStore.close()
@@ -162,6 +171,7 @@ class AgentForegroundService : Service() {
             updateNotification(if (heartbeat.busy) "在线 · 执行中" else "在线 · 空闲")
             scheduleTask(api, activeCredentials.token)
         } catch (error: AgentApiException) {
+            cancelIdleReturn("网络或服务端请求失败")
             val authenticationError = error.code in setOf(
                 "DEVICE_TOKEN_INVALID", "DEVICE_INSTALL_ID_CONFLICT", "DEVICE_DISABLED",
             )
@@ -174,6 +184,7 @@ class AgentForegroundService : Service() {
             )
             updateNotification(if (authenticationError) "设备认证失败" else "连接失败，等待网络恢复")
         } catch (error: Exception) {
+            cancelIdleReturn("Agent 运行异常")
             val configured = settingsStore.serverUrl().isNotBlank()
             val storedCredentials = runCatching { identityStore.credentials() }.getOrNull()
             stateStore.update(
@@ -192,10 +203,16 @@ class AgentForegroundService : Service() {
         flushPurchaseOutbox(api, token)
         val purchaseTask = api.nextPurchaseTask(token)
         if (purchaseTask != null) {
+            cancelIdleReturn("收到新的采购任务")
             schedulePurchaseTask(api, purchaseTask, token)
             return
         }
-        val task = api.nextTask(token) ?: return
+        val task = api.nextTask(token)
+        if (task == null) {
+            evaluateIdleReturn()
+            return
+        }
+        cancelIdleReturn("收到新的采集任务")
         if (!taskMutex.tryAcquire(task.taskId)) return
         if (task.status == "running") runningTaskId.set(task.taskId)
         stateStore.setActiveTask(task.taskId, "collection")
@@ -206,6 +223,7 @@ class AgentForegroundService : Service() {
                 runningTaskId.compareAndSet(task.taskId, null)
                 stateStore.clearActiveTask(task.taskId)
                 taskMutex.release(task.taskId)
+                triggerSync()
             }
         }
     }
@@ -221,12 +239,14 @@ class AgentForegroundService : Service() {
                 taskMutex.release(task.taskId)
                 stateStore.clearActiveTask(task.taskId)
                 runningTaskId.set(purchaseStore.activeTaskId())
+                triggerSync()
             }
         }
     }
 
     private fun executePurchaseTask(api: AgentApiClient, initial: PurchaseAgentTask, token: String) {
-        val wakeLock = acquireTaskWakeLock()
+        acquireTaskWakeLock()
+        var resultSafelyStored = false
         try {
             val claimed = if (initial.status == "pending") {
                 api.claimPurchaseTask(initial.taskId, UUID.randomUUID().toString(), token)
@@ -301,6 +321,8 @@ class AgentForegroundService : Service() {
             val requestId = UUID.randomUUID().toString()
             val payload = purchaseResultPayload(requestId, task.taskAttemptId, outcome)
             purchaseStore.completeAndEnqueue(task.taskId, task.taskAttemptId, requestId, payload)
+            resultSafelyStored = true
+            beginIdleReturnCooldown()
             flushPurchaseOutbox(api, token)
             val message = if (outcome.resultType == "failed") "${outcome.errorCode}：${outcome.message}" else outcome.message
             stateStore.update(if (outcome.resultType == "failed") "TASK_ERROR" else "ONLINE", message, tokenStored = true)
@@ -310,7 +332,8 @@ class AgentForegroundService : Service() {
         } catch (error: Exception) {
             stateStore.update("TASK_ERROR", error.message ?: "采购演练执行异常", tokenStored = true)
         } finally {
-            if (wakeLock.isHeld) wakeLock.release()
+            if (!resultSafelyStored) cancelIdleReturn("采购结果未安全保存")
+            releaseTaskWakeLock()
         }
     }
 
@@ -403,16 +426,17 @@ class AgentForegroundService : Service() {
 
 
     private fun executeTask(api: AgentApiClient, initialTask: cn.ilapage.goauto.agent.network.AgentTask, token: String) {
-        val wakeLock = acquireTaskWakeLock()
+        acquireTaskWakeLock()
         try {
             executeTaskWhileAwake(api, initialTask, token)
         } finally {
-            if (wakeLock.isHeld) wakeLock.release()
+            releaseTaskWakeLock()
         }
     }
 
     private fun executeTaskWhileAwake(api: AgentApiClient, initialTask: cn.ilapage.goauto.agent.network.AgentTask, token: String) {
         var started = initialTask.status == "running"
+        var resultSafelySubmitted = false
         try {
             val claimed = if (initialTask.status == "pending") {
                 api.claimTask(initialTask.taskId, UUID.randomUUID().toString(), token)
@@ -449,30 +473,134 @@ class AgentForegroundService : Service() {
                 CollectionAssembler.assemble(task.goodsIdSnapshot, execution.extracted)
             }
             api.submitResult(task.taskId, UUID.randomUUID().toString(), result, token)
+            resultSafelySubmitted = true
+            beginIdleReturnCooldown()
             stateStore.update("ONLINE", "任务 #${task.taskId} 已提交：${result.status}", tokenStored = true)
         } catch (error: TaskFailure) {
-            if (started) failSafely(api, initialTask.taskId, token, error.code, error.message ?: "采集失败")
+            if (started) {
+                resultSafelySubmitted = failSafely(api, initialTask.taskId, token, error.code, error.message ?: "采集失败")
+                if (resultSafelySubmitted) beginIdleReturnCooldown()
+            }
         } catch (error: AgentApiException) {
             stateStore.update("TASK_ERROR", "${error.code}：${error.message}", tokenStored = true)
         } catch (error: Exception) {
-            if (started) failSafely(api, initialTask.taskId, token, "AGENT_EXECUTION_ERROR", error.message ?: "Android 执行异常")
+            if (started) {
+                resultSafelySubmitted = failSafely(api, initialTask.taskId, token, "AGENT_EXECUTION_ERROR", error.message ?: "Android 执行异常")
+                if (resultSafelySubmitted) beginIdleReturnCooldown()
+            }
+        } finally {
+            if (!resultSafelySubmitted) cancelIdleReturn("采集结果未安全提交")
         }
     }
 
     @Suppress("DEPRECATION")
-    private fun acquireTaskWakeLock(): PowerManager.WakeLock =
-        getSystemService(PowerManager::class.java).newWakeLock(
+    private fun acquireTaskWakeLock() {
+        val wakeLock = getSystemService(PowerManager::class.java).newWakeLock(
             PowerManager.SCREEN_BRIGHT_WAKE_LOCK or PowerManager.ACQUIRE_CAUSES_WAKEUP,
             "$packageName:collection-task",
         ).apply {
             setReferenceCounted(false)
             acquire(TASK_WAKE_LOCK_TIMEOUT_MILLIS)
         }
+        taskWakeLock = wakeLock
+        taskWakeActive.set(true)
+        publishScreenPolicy()
+    }
 
-    private fun failSafely(api: AgentApiClient, taskId: Long, token: String, code: String, message: String) {
-        runCatching { api.submitFailure(taskId, UUID.randomUUID().toString(), code, message, token) }
+    private fun releaseTaskWakeLock() {
+        taskWakeLock?.let { lock -> if (lock.isHeld) lock.release() }
+        taskWakeLock = null
+        taskWakeActive.set(false)
+        publishScreenPolicy()
+    }
+
+    private fun failSafely(api: AgentApiClient, taskId: Long, token: String, code: String, message: String): Boolean {
+        val submitted = runCatching {
+            api.submitFailure(taskId, UUID.randomUUID().toString(), code, message, token)
+        }.isSuccess
         stateStore.update("TASK_ERROR", "$code：$message", tokenStored = true)
         updateNotification("任务 #$taskId 失败")
+        return submitted
+    }
+
+    private fun beginIdleReturnCooldown() {
+        val accessibility = GoAutoAccessibilityService.instance ?: return
+        val armed = idleReturn.arm(
+            nowMillis = SystemClock.elapsedRealtime(),
+            packageName = accessibility.currentPackage(),
+            foregroundRevision = accessibility.currentForegroundRevision(),
+        )
+        if (!armed) return
+        acquireCooldownWakeLock()
+        stateStore.update("ONLINE", "任务已结束，15 秒内无新任务将返回 Agent", tokenStored = true)
+        updateNotification("任务已结束 · 等待新任务")
+        publishScreenPolicy()
+        executor.schedule(::triggerSync, IdleReturnCoordinator.DEFAULT_COOLDOWN_MILLIS, TimeUnit.MILLISECONDS)
+    }
+
+    private fun evaluateIdleReturn() {
+        if (!idleReturn.isArmed()) return
+        val accessibility = GoAutoAccessibilityService.instance
+        if (accessibility == null) {
+            cancelIdleReturn("无障碍服务未就绪")
+            return
+        }
+        val localBoundarySafe = purchaseStore.interruptedAttempts().isEmpty() && taskMutex.currentTaskId() == null
+        when (idleReturn.evaluate(
+            nowMillis = SystemClock.elapsedRealtime(),
+            queuesEmpty = true,
+            localBoundarySafe = localBoundarySafe,
+            packageName = accessibility.currentPackage(),
+            foregroundRevision = accessibility.currentForegroundRevision(),
+        )) {
+            IdleReturnDecision.READY -> requestReturnToAgent(accessibility)
+            IdleReturnDecision.CANCELLED -> finishIdleReturn("已取消自动返回")
+            IdleReturnDecision.INACTIVE -> finishIdleReturn(null)
+            IdleReturnDecision.WAITING -> Unit
+        }
+    }
+
+    private fun requestReturnToAgent(accessibility: GoAutoAccessibilityService) {
+        val launched = accessibility.openAgentStatus()
+        if (launched) SystemClock.sleep(RETURN_CONFIRM_DELAY_MILLIS)
+        val returned = launched && accessibility.currentPackage() == packageName
+        finishIdleReturn(
+            if (returned) "15 秒内无新任务，已返回 Agent"
+            else "任务已结束；系统限制自动返回，请手动打开 Agent",
+        )
+    }
+
+    private fun cancelIdleReturn(reason: String) {
+        if (idleReturn.cancel()) Log.i("GoAutoAgent", "idle return cancelled: $reason")
+        finishIdleReturn(null)
+    }
+
+    private fun finishIdleReturn(message: String?) {
+        cooldownWakeLock?.let { lock -> if (lock.isHeld) lock.release() }
+        cooldownWakeLock = null
+        publishScreenPolicy()
+        message?.let {
+            stateStore.update("ONLINE", it, tokenStored = true)
+            updateNotification("在线 · 空闲")
+        }
+    }
+
+    @Suppress("DEPRECATION")
+    private fun acquireCooldownWakeLock() {
+        cooldownWakeLock?.let { lock -> if (lock.isHeld) lock.release() }
+        cooldownWakeLock = getSystemService(PowerManager::class.java).newWakeLock(
+            PowerManager.SCREEN_BRIGHT_WAKE_LOCK or PowerManager.ACQUIRE_CAUSES_WAKEUP,
+            "$packageName:idle-return",
+        ).apply {
+            setReferenceCounted(false)
+            acquire(IDLE_RETURN_WAKE_LOCK_TIMEOUT_MILLIS)
+        }
+    }
+
+    private fun publishScreenPolicy() {
+        stateStore.setKeepScreenOn(
+            ScreenAwakeResolver.shouldKeepScreenOn(taskWakeActive.get(), idleReturn.isArmed()),
+        )
     }
 
     private fun deviceInfo(): DeviceInfo = DeviceInfo(
@@ -544,6 +672,8 @@ class AgentForegroundService : Service() {
         private const val NOTIFICATION_ID = 1001
         private const val HEARTBEAT_SECONDS = 15L
         private const val TASK_WAKE_LOCK_TIMEOUT_MILLIS = 5 * 60 * 1000L
+        private const val IDLE_RETURN_WAKE_LOCK_TIMEOUT_MILLIS = 30_000L
+        private const val RETURN_CONFIRM_DELAY_MILLIS = 750L
 
         fun start(context: Context, reconnect: Boolean = false) {
             val intent = Intent(context, AgentForegroundService::class.java).apply {
diff --git a/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentStateStore.kt b/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentStateStore.kt
index f3d6cc7..27d245b 100644
--- a/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentStateStore.kt
+++ b/android/app/src/main/java/cn/ilapage/goauto/agent/service/AgentStateStore.kt
@@ -12,6 +12,7 @@ data class AgentState(
     val tokenStored: Boolean,
     val currentTaskId: Long?,
     val currentTaskType: String?,
+    val keepScreenOn: Boolean,
 )
 
 class AgentSettingsStore(context: Context) {
@@ -69,8 +70,13 @@ class AgentStateStore(context: Context) {
         tokenStored = preferences.getBoolean(TOKEN_STORED, false),
         currentTaskId = preferences.getLong(CURRENT_TASK_ID, 0L).takeIf { it > 0L },
         currentTaskType = preferences.getString(CURRENT_TASK_TYPE, null),
+        keepScreenOn = preferences.getBoolean(KEEP_SCREEN_ON, false),
     )
 
+    fun setKeepScreenOn(enabled: Boolean) {
+        preferences.edit().putBoolean(KEEP_SCREEN_ON, enabled).apply()
+    }
+
     fun setActiveTask(taskId: Long, taskType: String) {
         require(taskId > 0L)
         require(taskType == "collection" || taskType == "purchase")
@@ -98,5 +104,6 @@ class AgentStateStore(context: Context) {
         const val TOKEN_STORED = "token_stored"
         const val CURRENT_TASK_ID = "current_task_id"
         const val CURRENT_TASK_TYPE = "current_task_type"
+        const val KEEP_SCREEN_ON = "keep_screen_on"
     }
 }
diff --git a/android/app/src/main/java/cn/ilapage/goauto/agent/service/IdleReturnCoordinator.kt b/android/app/src/main/java/cn/ilapage/goauto/agent/service/IdleReturnCoordinator.kt
new file mode 100644
index 0000000..8cbb52b
--- /dev/null
+++ b/android/app/src/main/java/cn/ilapage/goauto/agent/service/IdleReturnCoordinator.kt
@@ -0,0 +1,87 @@
+package cn.ilapage.goauto.agent.service
+
+enum class IdleReturnDecision {
+    INACTIVE,
+    WAITING,
+    READY,
+    CANCELLED,
+}
+
+/** Pure state machine for the post-task return window. Queue I/O stays in the service poller. */
+class IdleReturnCoordinator(
+    private val cooldownMillis: Long = DEFAULT_COOLDOWN_MILLIS,
+) {
+    private var ticket: Ticket? = null
+
+    init {
+        require(cooldownMillis > 0L)
+    }
+
+    @Synchronized
+    fun arm(nowMillis: Long, packageName: String?, foregroundRevision: Long): Boolean {
+        if (!IdleReturnForegroundPolicy.isAutomationPackage(packageName)) {
+            ticket = null
+            return false
+        }
+        ticket = Ticket(nowMillis, requireNotNull(packageName), foregroundRevision)
+        return true
+    }
+
+    @Synchronized
+    fun evaluate(
+        nowMillis: Long,
+        queuesEmpty: Boolean,
+        localBoundarySafe: Boolean,
+        packageName: String?,
+        foregroundRevision: Long,
+    ): IdleReturnDecision {
+        val current = ticket ?: return IdleReturnDecision.INACTIVE
+        if (!queuesEmpty || !localBoundarySafe) {
+            ticket = null
+            return IdleReturnDecision.CANCELLED
+        }
+        if (packageName != current.packageName || foregroundRevision != current.foregroundRevision) {
+            ticket = null
+            return IdleReturnDecision.CANCELLED
+        }
+        if (nowMillis - current.startedAtMillis < cooldownMillis) return IdleReturnDecision.WAITING
+        ticket = null
+        return IdleReturnDecision.READY
+    }
+
+    @Synchronized
+    fun cancel(): Boolean {
+        val wasArmed = ticket != null
+        ticket = null
+        return wasArmed
+    }
+
+    @Synchronized
+    fun isArmed(): Boolean = ticket != null
+
+    private data class Ticket(
+        val startedAtMillis: Long,
+        val packageName: String,
+        val foregroundRevision: Long,
+    )
+
+    companion object {
+        const val DEFAULT_COOLDOWN_MILLIS = 15_000L
+    }
+}
+
+object IdleReturnForegroundPolicy {
+    private val automationPackages = setOf(
+        "com.xunmeng.pinduoduo",
+        "com.heytap.browser",
+        "com.android.chrome",
+        "com.android.browser",
+    )
+
+    fun isAutomationPackage(packageName: String?): Boolean = packageName in automationPackages
+}
+
+object ScreenAwakeResolver {
+    fun shouldKeepScreenOn(taskRunning: Boolean, cooldownArmed: Boolean): Boolean =
+        taskRunning || cooldownArmed
+}
diff --git a/android/app/src/test/java/cn/ilapage/goauto/agent/IdleReturnCoordinatorTest.kt b/android/app/src/test/java/cn/ilapage/goauto/agent/IdleReturnCoordinatorTest.kt
new file mode 100644
index 0000000..8e454c0
--- /dev/null
+++ b/android/app/src/test/java/cn/ilapage/goauto/agent/IdleReturnCoordinatorTest.kt
@@ -0,0 +1,67 @@
+package cn.ilapage.goauto.agent
+
+import cn.ilapage.goauto.agent.service.IdleReturnCoordinator
+import cn.ilapage.goauto.agent.service.IdleReturnDecision
+import cn.ilapage.goauto.agent.service.ScreenAwakeResolver
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class IdleReturnCoordinatorTest {
+    @Test
+    fun `returns only after cooldown and successful empty queue confirmation`() {
+        val coordinator = IdleReturnCoordinator()
+        assertTrue(coordinator.arm(1_000L, "com.xunmeng.pinduoduo", 7L))
+        assertEquals(
+            IdleReturnDecision.WAITING,
+            coordinator.evaluate(15_999L, true, true, "com.xunmeng.pinduoduo", 7L),
+        )
+        assertEquals(
+            IdleReturnDecision.READY,
+            coordinator.evaluate(16_000L, true, true, "com.xunmeng.pinduoduo", 7L),
+        )
+        assertFalse(coordinator.isArmed())
+    }
+
+    @Test
+    fun `foreground change cancels even when user comes back to same app`() {
+        val coordinator = IdleReturnCoordinator()
+        coordinator.arm(0L, "com.xunmeng.pinduoduo", 3L)
+        assertEquals(
+            IdleReturnDecision.CANCELLED,
+            coordinator.evaluate(15_000L, true, true, "com.xunmeng.pinduoduo", 5L),
+        )
+    }
+
+    @Test
+    fun `active queue or unsafe local boundary cancels`() {
+        val withTask = IdleReturnCoordinator().apply { arm(0L, "com.android.chrome", 1L) }
+        assertEquals(
+            IdleReturnDecision.CANCELLED,
+            withTask.evaluate(15_000L, false, true, "com.android.chrome", 1L),
+        )
+        val unsafe = IdleReturnCoordinator().apply { arm(0L, "com.android.chrome", 1L) }
+        assertEquals(
+            IdleReturnDecision.CANCELLED,
+            unsafe.evaluate(15_000L, true, false, "com.android.chrome", 1L),
+        )
+    }
+
+    @Test
+    fun `does not arm outside automation apps`() {
+        val coordinator = IdleReturnCoordinator()
+        assertFalse(coordinator.arm(0L, "com.tencent.mm", 1L))
+        assertEquals(
+            IdleReturnDecision.INACTIVE,
+            coordinator.evaluate(20_000L, true, true, "com.tencent.mm", 1L),
+        )
+    }
+
+    @Test
+    fun `screen stays awake only during task or cooldown`() {
+        assertFalse(ScreenAwakeResolver.shouldKeepScreenOn(false, false))
+        assertTrue(ScreenAwakeResolver.shouldKeepScreenOn(true, false))
+        assertTrue(ScreenAwakeResolver.shouldKeepScreenOn(false, true))
+    }
+}
diff --git a/docs/02-architecture-and-code-map.md b/docs/02-architecture-and-code-map.md
index cac0059..a627d8a 100644
--- a/docs/02-architecture-and-code-map.md
+++ b/docs/02-architecture-and-code-map.md
@@ -2,8 +2,8 @@
 generated: true (请先修改 Gitea Wiki，禁止直接编辑本文件)
 wiki_page: Architecture-and-Code-Map
 wiki_url: https://git.ilapage.cn/OPC/goauto/wiki/Architecture-and-Code-Map.-
-wiki_revision: d076a86d9282a98c8bb3f00deb0edee68041f2ec
-synchronized_at: 2026-08-25T08:52:07Z
+wiki_revision: 1c9841a942b5d5682ddada2ee7202e93adc422e4
+synchronized_at: 2026-08-25T09:44:21Z
 <!-- gitea-wiki-mirror:end -->
 
 # 架构与代码地图
@@ -158,3 +158,11 @@ Android Portal/Agent
 - 设置页维护服务器地址和设备名称，测试连接只访问 `GET /api/v1/health`；保存后沿用当前 installId / Device Token 重新连接。执行任务或测试连接期间表单与按钮禁用。
 - 设置页只显示 Token 是否配置，不返回或显示明文；不包含 PDD 账号、采购写操作或支付入口。
 - `AgentStateStore` 保存界面所需的当前任务类型/编号摘要；任务结束后由执行服务清除。它不保存控件树、截图、完整规则或凭据。
+
+## Android Agent 任务结束冷却与返回（#89）
+
+- `AgentForegroundService` 在采集结果已提交，或采购结果与 Outbox 已在同一事务安全保存后，建立 15 秒任务结束冷却；不新增第二套队列轮询器。
+- 冷却到期仍由现有任务轮询按“采购优先、再采集”依次确认两个队列都为空。任何新任务、网络/服务端异常或本地未解除的不可逆采购边界都会取消返回。
+- `IdleReturnCoordinator` 只保存冷却时间、自动化前台包名与无障碍前台切换序号，不保存控件树或截图。用户切换到其他 App 后，即使又返回 PDD，也不会被强制拉回 Agent。
+- 返回请求只允许从 Agent 本次自动化停留的 PDD 或受支持浏览器页面发起，并由无障碍服务打开 `MainActivity` 状态 Tab；Android 后台 Activity 启动限制导致失败时只提示手动打开，不重复强拉。
+- 任务执行和冷却分别使用带超时的亮屏锁；`MainActivity` 仅在运行态标记要求时设置 `FLAG_KEEP_SCREEN_ON`。任务、新任务接管、取消、返回或服务销毁后统一释放，不绕过设备 PIN、图案或密码。
diff --git a/docs/04-local-development-and-verification.md b/docs/04-local-development-and-verification.md
index f101eaf..38ddacc 100644
--- a/docs/04-local-development-and-verification.md
+++ b/docs/04-local-development-and-verification.md
@@ -2,8 +2,8 @@
 generated: true (请先修改 Gitea Wiki，禁止直接编辑本文件)
 wiki_page: Local-Development-and-Verification
 wiki_url: https://git.ilapage.cn/OPC/goauto/wiki/Local-Development-and-Verification.-
-wiki_revision: f79711e63e200dc8f7bdc0b04bf5a87f35e2a405
-synchronized_at: 2026-08-25T08:52:22Z
+wiki_revision: dc484e1aa48172d502939e8ebe0ad0e6bd83c7ea
+synchronized_at: 2026-08-25T09:44:34Z
 <!-- gitea-wiki-mirror:end -->
 
 # 本地开发与验证
@@ -199,3 +199,16 @@ adb shell am start -n cn.ilapage.goauto.agent/.MainActivity
 - 任务执行中服务器地址、设备名称、测试和保存均禁用；Token 只显示“已配置/未配置”。
 - 采集/采购 Tab 在 #90 前只显示明确占位，不应出现采购写操作、PDD 凭据或支付入口。
 - Release 仍只接受 HTTPS；Debug 可使用 HTTP 进行局域网联调。安装前必须确认设备空闲，避免重启 Agent 中断任务。
+
+### Android Agent 0.3.1 空闲返回与亮屏检查
+
+#89 起 Debug APK 版本为 0.3.1（versionCode 4）。先确认设备空闲，再覆盖安装；安装后系统可能关闭无障碍服务，需要人工重新开启。
+
+真机验证应至少覆盖：
+
+- 完成一个不会支付的采集或演练任务，确认结果已提交后约 15 秒返回 Agent“状态”Tab；记录 ROM 是否限制后台 Activity 启动。
+- 冷却 15 秒内创建任一类型新任务，确认 Agent 取消返回并继续按采购优先、采集其次执行。
+- 冷却期间断网，确认不会把网络失败当成空队列，也不会返回。
+- 冷却期间人工切换到其他 App，确认 Agent 不会强拉回；即使再切回 PDD，前台切换序号变化也会取消本次返回。
+- 使用 `adb shell dumpsys power` 或屏幕实际状态确认任务执行与冷却期间亮屏；返回、取消或服务停止后不再持有 `cn.ilapage.goauto.agent:collection-task` / `:idle-return` WakeLock。
+- 该流程不自动解锁安全锁屏，不点击创建订单或支付。