diff --git a/apps/android/app/src/main/java/com/steipete/clawdis/node/MainActivity.kt b/apps/android/app/src/main/java/com/steipete/clawdis/node/MainActivity.kt
index e3a6c1840..8f8059525 100644
--- a/apps/android/app/src/main/java/com/steipete/clawdis/node/MainActivity.kt
+++ b/apps/android/app/src/main/java/com/steipete/clawdis/node/MainActivity.kt
@@ -3,6 +3,7 @@ package com.steipete.clawdis.node
 import android.Manifest
 import android.os.Bundle
 import android.os.Build
+import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.viewModels
@@ -10,7 +11,11 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.ui.Modifier
 import androidx.core.content.ContextCompat
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import com.steipete.clawdis.node.ui.RootScreen
+import kotlinx.coroutines.launch
 
 class MainActivity : ComponentActivity() {
   private val viewModel: MainViewModel by viewModels()
@@ -21,6 +26,19 @@ class MainActivity : ComponentActivity() {
     requestNotificationPermissionIfNeeded()
     NodeForegroundService.start(this)
     viewModel.camera.attachLifecycleOwner(this)
+
+    lifecycleScope.launch {
+      repeatOnLifecycle(Lifecycle.State.STARTED) {
+        viewModel.preventSleep.collect { enabled ->
+          if (enabled) {
+            window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+          } else {
+            window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+          }
+        }
+      }
+    }
+
     setContent {
       MaterialTheme {
         Surface(modifier = Modifier) {
diff --git a/apps/android/app/src/main/java/com/steipete/clawdis/node/MainViewModel.kt b/apps/android/app/src/main/java/com/steipete/clawdis/node/MainViewModel.kt
index 527aa470a..bad6c94ea 100644
--- a/apps/android/app/src/main/java/com/steipete/clawdis/node/MainViewModel.kt
+++ b/apps/android/app/src/main/java/com/steipete/clawdis/node/MainViewModel.kt
@@ -23,6 +23,7 @@ class MainViewModel(app: Application) : AndroidViewModel(app) {
   val instanceId: StateFlow<String> = runtime.instanceId
   val displayName: StateFlow<String> = runtime.displayName
   val cameraEnabled: StateFlow<Boolean> = runtime.cameraEnabled
+  val preventSleep: StateFlow<Boolean> = runtime.preventSleep
   val wakeWords: StateFlow<List<String>> = runtime.wakeWords
   val manualEnabled: StateFlow<Boolean> = runtime.manualEnabled
   val manualHost: StateFlow<String> = runtime.manualHost
@@ -44,6 +45,10 @@ class MainViewModel(app: Application) : AndroidViewModel(app) {
     runtime.setCameraEnabled(value)
   }
 
+  fun setPreventSleep(value: Boolean) {
+    runtime.setPreventSleep(value)
+  }
+
   fun setManualEnabled(value: Boolean) {
     runtime.setManualEnabled(value)
   }
diff --git a/apps/android/app/src/main/java/com/steipete/clawdis/node/NodeRuntime.kt b/apps/android/app/src/main/java/com/steipete/clawdis/node/NodeRuntime.kt
index 60e2093be..2e3b0e6fd 100644
--- a/apps/android/app/src/main/java/com/steipete/clawdis/node/NodeRuntime.kt
+++ b/apps/android/app/src/main/java/com/steipete/clawdis/node/NodeRuntime.kt
@@ -78,6 +78,7 @@ class NodeRuntime(context: Context) {
   val instanceId: StateFlow<String> = prefs.instanceId
   val displayName: StateFlow<String> = prefs.displayName
   val cameraEnabled: StateFlow<Boolean> = prefs.cameraEnabled
+  val preventSleep: StateFlow<Boolean> = prefs.preventSleep
   val wakeWords: StateFlow<List<String>> = prefs.wakeWords
   val manualEnabled: StateFlow<Boolean> = prefs.manualEnabled
   val manualHost: StateFlow<String> = prefs.manualHost
@@ -145,6 +146,10 @@ class NodeRuntime(context: Context) {
     prefs.setCameraEnabled(value)
   }
 
+  fun setPreventSleep(value: Boolean) {
+    prefs.setPreventSleep(value)
+  }
+
   fun setManualEnabled(value: Boolean) {
     prefs.setManualEnabled(value)
   }
diff --git a/apps/android/app/src/main/java/com/steipete/clawdis/node/SecurePrefs.kt b/apps/android/app/src/main/java/com/steipete/clawdis/node/SecurePrefs.kt
index b6dd875e8..94f1b2fa1 100644
--- a/apps/android/app/src/main/java/com/steipete/clawdis/node/SecurePrefs.kt
+++ b/apps/android/app/src/main/java/com/steipete/clawdis/node/SecurePrefs.kt
@@ -41,6 +41,9 @@ class SecurePrefs(context: Context) {
   private val _cameraEnabled = MutableStateFlow(prefs.getBoolean("camera.enabled", true))
   val cameraEnabled: StateFlow<Boolean> = _cameraEnabled
 
+  private val _preventSleep = MutableStateFlow(prefs.getBoolean("screen.preventSleep", true))
+  val preventSleep: StateFlow<Boolean> = _preventSleep
+
   private val _manualEnabled = MutableStateFlow(prefs.getBoolean("bridge.manual.enabled", false))
   val manualEnabled: StateFlow<Boolean> = _manualEnabled
 
@@ -74,6 +77,11 @@ class SecurePrefs(context: Context) {
     _cameraEnabled.value = value
   }
 
+  fun setPreventSleep(value: Boolean) {
+    prefs.edit().putBoolean("screen.preventSleep", value).apply()
+    _preventSleep.value = value
+  }
+
   fun setManualEnabled(value: Boolean) {
     prefs.edit().putBoolean("bridge.manual.enabled", value).apply()
     _manualEnabled.value = value
diff --git a/apps/android/app/src/main/java/com/steipete/clawdis/node/ui/SettingsSheet.kt b/apps/android/app/src/main/java/com/steipete/clawdis/node/ui/SettingsSheet.kt
index 6bfa0b428..699b96299 100644
--- a/apps/android/app/src/main/java/com/steipete/clawdis/node/ui/SettingsSheet.kt
+++ b/apps/android/app/src/main/java/com/steipete/clawdis/node/ui/SettingsSheet.kt
@@ -46,6 +46,7 @@ fun SettingsSheet(viewModel: MainViewModel) {
   val instanceId by viewModel.instanceId.collectAsState()
   val displayName by viewModel.displayName.collectAsState()
   val cameraEnabled by viewModel.cameraEnabled.collectAsState()
+  val preventSleep by viewModel.preventSleep.collectAsState()
   val wakeWords by viewModel.wakeWords.collectAsState()
   val isConnected by viewModel.isConnected.collectAsState()
   val manualEnabled by viewModel.manualEnabled.collectAsState()
@@ -155,6 +156,17 @@ fun SettingsSheet(viewModel: MainViewModel) {
 
     item { HorizontalDivider() }
 
+    item { Text("Screen") }
+    item {
+      Row(horizontalArrangement = Arrangement.spacedBy(12.dp), modifier = Modifier.fillMaxWidth()) {
+        Switch(checked = preventSleep, onCheckedChange = viewModel::setPreventSleep)
+        Text(if (preventSleep) "Prevent Sleep" else "Allow Sleep")
+      }
+    }
+    item { Text("Keeps the screen awake while Clawdis is open.") }
+
+    item { HorizontalDivider() }
+
     item { Text("Bridge") }
     item { Text("Status: $statusText") }
     item { if (serverName != null) Text("Server: $serverName") }
diff --git a/apps/ios/Sources/RootCanvas.swift b/apps/ios/Sources/RootCanvas.swift
index 9def87f22..61e5a39ab 100644
--- a/apps/ios/Sources/RootCanvas.swift
+++ b/apps/ios/Sources/RootCanvas.swift
@@ -1,9 +1,12 @@
 import SwiftUI
+import UIKit
 
 struct RootCanvas: View {
     @Environment(NodeAppModel.self) private var appModel
     @Environment(VoiceWakeManager.self) private var voiceWake
+    @Environment(\.scenePhase) private var scenePhase
     @AppStorage(VoiceWakePreferences.enabledKey) private var voiceWakeEnabled: Bool = false
+    @AppStorage("screen.preventSleep") private var preventSleep: Bool = true
     @State private var presentedSheet: PresentedSheet?
     @State private var voiceWakeToastText: String?
     @State private var toastDismissTask: Task<Void, Never>?
@@ -63,6 +66,9 @@ struct RootCanvas: View {
             }
         }
         .preferredColorScheme(.dark)
+        .onAppear { self.updateIdleTimer() }
+        .onChange(of: self.preventSleep) { _, _ in self.updateIdleTimer() }
+        .onChange(of: self.scenePhase) { _, _ in self.updateIdleTimer() }
         .onChange(of: self.voiceWake.lastTriggeredCommand) { _, newValue in
             guard let newValue else { return }
             let trimmed = newValue.trimmingCharacters(in: .whitespacesAndNewlines)
@@ -83,6 +89,7 @@ struct RootCanvas: View {
             }
         }
         .onDisappear {
+            UIApplication.shared.isIdleTimerDisabled = false
             self.toastDismissTask?.cancel()
             self.toastDismissTask = nil
         }
@@ -104,6 +111,10 @@ struct RootCanvas: View {
 
         return .disconnected
     }
+
+    private func updateIdleTimer() {
+        UIApplication.shared.isIdleTimerDisabled = (self.scenePhase == .active && self.preventSleep)
+    }
 }
 
 private struct OverlayButton: View {
diff --git a/apps/ios/Sources/Settings/SettingsTab.swift b/apps/ios/Sources/Settings/SettingsTab.swift
index b226db058..8de2be018 100644
--- a/apps/ios/Sources/Settings/SettingsTab.swift
+++ b/apps/ios/Sources/Settings/SettingsTab.swift
@@ -21,6 +21,7 @@ struct SettingsTab: View {
     @AppStorage("node.instanceId") private var instanceId: String = UUID().uuidString
     @AppStorage("voiceWake.enabled") private var voiceWakeEnabled: Bool = false
     @AppStorage("camera.enabled") private var cameraEnabled: Bool = true
+    @AppStorage("screen.preventSleep") private var preventSleep: Bool = true
     @AppStorage("bridge.preferredStableID") private var preferredBridgeStableID: String = ""
     @AppStorage("bridge.lastDiscoveredStableID") private var lastDiscoveredBridgeStableID: String = ""
     @AppStorage("bridge.manual.enabled") private var manualBridgeEnabled: Bool = false
@@ -73,6 +74,13 @@ struct SettingsTab: View {
                         .foregroundStyle(.secondary)
                 }
 
+                Section("Screen") {
+                    Toggle("Prevent Sleep", isOn: self.$preventSleep)
+                    Text("Keeps the screen awake while Clawdis is open.")
+                        .font(.footnote)
+                        .foregroundStyle(.secondary)
+                }
+
                 Section("Bridge") {
                     LabeledContent("Discovery", value: self.bridgeController.discoveryStatusText)
                     LabeledContent("Status", value: self.appModel.bridgeStatusText)