diff --git a/shell/plugins/services/idle/IdleModel.js b/shell/plugins/services/idle/IdleModel.js
index 8e2315d0..f13769ee 100644
--- a/shell/plugins/services/idle/IdleModel.js
+++ b/shell/plugins/services/idle/IdleModel.js
@@ -4,6 +4,26 @@ function secondsFromConfig(value, fallback) {
   return Math.floor(n)
 }
 
+// 0 means the action is disabled, not "fire immediately". min(0, 300) would
+// otherwise make IdleMonitor report idle as soon as an inhibitor is released.
+function firstIdleTimeout(screensaverSeconds, lockSeconds) {
+  var times = []
+  if (screensaverSeconds > 0) times.push(screensaverSeconds)
+  if (lockSeconds > 0) times.push(lockSeconds)
+  if (times.length === 0) return 0
+  var min = times[0]
+  for (var i = 1; i < times.length; i++) {
+    if (times[i] < min) min = times[i]
+  }
+  return min
+}
+
+function delayAfterFirstIdle(timeoutSeconds, firstIdleSeconds) {
+  if (!(timeoutSeconds > 0)) return 0
+  var delay = timeoutSeconds - firstIdleSeconds
+  return delay > 0 ? delay : 0
+}
+
 function eventParts(event, count) {
   try {
     if (event && event.parse) return event.parse(count)
@@ -46,6 +66,8 @@ function screensaverWindowsAfter(windows, address, visible) {
 if (typeof module !== "undefined") {
   module.exports = {
     secondsFromConfig: secondsFromConfig,
+    firstIdleTimeout: firstIdleTimeout,
+    delayAfterFirstIdle: delayAfterFirstIdle,
     eventParts: eventParts,
     screensaverWindowsAfter: screensaverWindowsAfter
   }
diff --git a/shell/plugins/services/idle/Service.qml b/shell/plugins/services/idle/Service.qml
index 19dab2a2..d0ed8a26 100644
--- a/shell/plugins/services/idle/Service.qml
+++ b/shell/plugins/services/idle/Service.qml
@@ -21,9 +21,12 @@ Item {
     ? shell.shellConfig.idle : (shell && shell.idleConfig ? shell.idleConfig : ({}))
   readonly property int screensaverTimeoutSeconds: secondsFromConfig(idleConfig.screensaver, defaultScreensaverSeconds)
   readonly property int lockTimeoutSeconds: secondsFromConfig(idleConfig.lock, defaultLockSeconds)
-  readonly property int firstIdleTimeoutSeconds: Math.min(screensaverTimeoutSeconds, lockTimeoutSeconds)
-  readonly property int screensaverDelaySeconds: Math.max(0, screensaverTimeoutSeconds - firstIdleTimeoutSeconds)
-  readonly property int lockDelaySeconds: Math.max(0, lockTimeoutSeconds - firstIdleTimeoutSeconds)
+  readonly property bool screensaverEnabled: screensaverTimeoutSeconds > 0
+  readonly property bool lockEnabled: lockTimeoutSeconds > 0
+  readonly property bool idleTimersEnabled: screensaverEnabled || lockEnabled
+  readonly property int firstIdleTimeoutSeconds: IdleModel.firstIdleTimeout(screensaverTimeoutSeconds, lockTimeoutSeconds)
+  readonly property int screensaverDelaySeconds: IdleModel.delayAfterFirstIdle(screensaverTimeoutSeconds, firstIdleTimeoutSeconds)
+  readonly property int lockDelaySeconds: IdleModel.delayAfterFirstIdle(lockTimeoutSeconds, firstIdleTimeoutSeconds)
   readonly property bool idleEnabled: stayAwakeStateLoaded && !stayAwake
   readonly property string screensaverClass: "org.omarchy.screensaver"
 
@@ -92,11 +95,23 @@ Item {
     root.screensaverStartedThisCycle = false
     resetScreensaverWindows()
 
-    if (root.screensaverDelaySeconds === 0) launchScreensaver()
-    else screensaverTimer.restart()
+    // Set this cycle's deadlines once: a bound interval would restart a pending
+    // timer from the moment shell.json changes, locking early or late.
+    if (root.screensaverEnabled) {
+      if (root.screensaverDelaySeconds === 0) launchScreensaver()
+      else {
+        screensaverTimer.interval = root.screensaverDelaySeconds * 1000
+        screensaverTimer.restart()
+      }
+    }
 
-    if (root.lockDelaySeconds === 0) lockSystem("lock-timeout-immediate")
-    else lockTimer.restart()
+    if (root.lockEnabled) {
+      if (root.lockDelaySeconds === 0) lockSystem("lock-timeout-immediate")
+      else {
+        lockTimer.interval = root.lockDelaySeconds * 1000
+        lockTimer.restart()
+      }
+    }
   }
 
   function cancelIdleCycle(reason) {
@@ -173,7 +188,7 @@ Item {
 
   function handleIdleChanged() {
     logEvent("idle-monitor", idleMonitor.isIdle ? "idle" : "active")
-    if (!root.idleEnabled) return
+    if (!root.idleEnabled || !root.idleTimersEnabled) return
 
     if (idleMonitor.isIdle) startIdleCycle()
     else handleActiveSignal()
@@ -249,26 +264,27 @@ Item {
     return applyStayAwake(!value, true, "ipc")
   }
 
+  // With both timeouts at 0 the monitor stops reporting, so nothing else would end a running cycle.
+  onIdleTimersEnabledChanged: if (!idleTimersEnabled) cancelIdleCycle("idle-timers-disabled")
+
   IdleMonitor {
     id: idleMonitor
-    enabled: root.idleEnabled
-    timeout: root.firstIdleTimeoutSeconds
+    enabled: root.idleEnabled && root.idleTimersEnabled
+    timeout: Math.max(1, root.firstIdleTimeoutSeconds)
     respectInhibitors: true
     onIsIdleChanged: root.handleIdleChanged()
   }
 
   Timer {
     id: screensaverTimer
-    interval: root.screensaverDelaySeconds * 1000
     repeat: false
-    onTriggered: root.launchScreensaver()
+    onTriggered: if (root.screensaverEnabled) root.launchScreensaver()
   }
 
   Timer {
     id: lockTimer
-    interval: root.lockDelaySeconds * 1000
     repeat: false
-    onTriggered: if (root.idleEnabled && root.idledThisCycle) root.lockSystem("lock-timeout")
+    onTriggered: if (root.idleEnabled && root.idledThisCycle && root.lockEnabled) root.lockSystem("lock-timeout")
   }
 
   Timer {
diff --git a/test/shell.d/idle-test.sh b/test/shell.d/idle-test.sh
index 62a19c2c..450c8d5a 100644
--- a/test/shell.d/idle-test.sh
+++ b/test/shell.d/idle-test.sh
@@ -5,11 +5,56 @@ set -euo pipefail
 source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
 
 run_node_test <<'JS'
+const fs = require('fs')
 const idle = requireFromRoot('shell/plugins/services/idle/IdleModel.js')
+const serviceSource = fs.readFileSync(root + '/shell/plugins/services/idle/Service.qml', 'utf8')
 
 assertEqual(idle.secondsFromConfig('42.9', 10), 42, 'idle floors configured seconds')
 assertEqual(idle.secondsFromConfig('-1', 10), 10, 'idle rejects negative seconds')
 assertEqual(idle.secondsFromConfig('nope', 10), 10, 'idle rejects invalid seconds')
+assertEqual(idle.secondsFromConfig(0, 300), 0, 'idle keeps an explicit zero timeout')
+assertEqual(idle.firstIdleTimeout(150, 300), 150, 'idle uses the sooner of screensaver and lock')
+assertEqual(idle.firstIdleTimeout(0, 300), 300, 'idle ignores a disabled screensaver when computing first idle')
+assertEqual(idle.firstIdleTimeout(150, 0), 150, 'idle ignores a disabled lock when computing first idle')
+assertEqual(idle.firstIdleTimeout(0, 0), 0, 'idle has no first-idle timeout when both actions are disabled')
+assertEqual(idle.delayAfterFirstIdle(300, 150), 150, 'idle delays lock until its own timeout')
+assertEqual(idle.delayAfterFirstIdle(150, 150), 0, 'idle fires an action immediately when it is the first timeout')
+assertEqual(idle.delayAfterFirstIdle(0, 150), 0, 'idle does not schedule a disabled action')
+
+assert(
+  serviceSource.includes('IdleModel.firstIdleTimeout(screensaverTimeoutSeconds, lockTimeoutSeconds)'),
+  'idle ignores a zero timeout when computing the first idle deadline'
+)
+assert(
+  /enabled: root\.idleEnabled && root\.idleTimersEnabled/.test(serviceSource),
+  'idle monitor is off when both screensaver and lock are disabled'
+)
+assert(
+  /if \(root\.lockEnabled\) \{\s*\n\s*if \(root\.lockDelaySeconds === 0\) lockSystem/.test(serviceSource),
+  'idle does not lock immediately when lock timeout is disabled'
+)
+assert(
+  /id: screensaverTimer[\s\S]*?onTriggered: if \(root\.screensaverEnabled\) root\.launchScreensaver\(\)/.test(serviceSource),
+  'idle does not launch a pending screensaver once its timeout is set to 0'
+)
+assert(
+  /id: lockTimer[\s\S]*?onTriggered: if \([^)]*root\.lockEnabled\) root\.lockSystem\("lock-timeout"\)/.test(serviceSource),
+  'idle does not fire a pending lock once its timeout is set to 0'
+)
+assert(
+  /lockTimer\.interval = root\.lockDelaySeconds \* 1000\s*\n\s*lockTimer\.restart\(\)/.test(serviceSource) &&
+    !/interval: root\.lockDelaySeconds/.test(serviceSource),
+  'idle keeps a pending lock on its deadline when shell.json changes mid-cycle'
+)
+assert(
+  /screensaverTimer\.interval = root\.screensaverDelaySeconds \* 1000\s*\n\s*screensaverTimer\.restart\(\)/.test(serviceSource) &&
+    !/interval: root\.screensaverDelaySeconds/.test(serviceSource),
+  'idle keeps a pending screensaver on its deadline when shell.json changes mid-cycle'
+)
+assert(
+  /onIdleTimersEnabledChanged: if \(!idleTimersEnabled\) cancelIdleCycle\(/.test(serviceSource),
+  'idle ends a running cycle when both timeouts are set to 0'
+)
 
 assertDeepEqual(idle.eventParts({ data: 'a,b,c' }, 2), ['a', 'b', 'c'], 'idle parses raw event data')
 assertDeepEqual(