diff --git a/cmd/gui/main.js b/cmd/gui/main.js
index 6c845c8..d7ed354 100644
--- a/cmd/gui/main.js
+++ b/cmd/gui/main.js
@@ -1428,7 +1428,8 @@ function executeHomeagentCmd(capability, reqId) {
     }
     case "screensue": {
       // 在配置的目标屏幕上拉起独立窗口显示内容（支持文字 / HTML）
-      var duration = 0; // 显示时长(秒)，0=常驻
+      // 默认 5 秒自动关闭；命令可带 [秒] 指定时长，0 = 永不超时（常驻，用户手动关闭）
+      var duration = 5;
       var raw = String(capability || "")
         .replace(/^screensue/, "")
         .trim();
@@ -1438,9 +1439,15 @@ function executeHomeagentCmd(capability, reqId) {
         const prefs = loadGuiPrefs();
         const db = prefs.deviceBridge || {};
         dispIdx = parseInt(db.screensueDisplay || "0", 10) || 0;
-        duration = parseInt(db.screensueDuration || "0", 10) || 0;
+        const cfgDur = db.screensueDuration;
+        if (cfgDur === undefined || cfgDur === null || cfgDur === "") {
+          duration = 5; // 未配置时默认 5 秒
+        } else {
+          duration = parseInt(cfgDur, 10);
+          if (!Number.isFinite(duration) || duration < 0) duration = 5;
+        }
       } catch (e) {}
-      // 参数支持 "screensue [时长秒] 内容"：首个纯数字 token 作为时长
+      // 参数支持 "screensue [时长秒] 内容"：首个纯数字 token 作为时长（0=永不超时）
       const tokens = raw.split(/\s+/);
       if (tokens.length > 1 && /^\d+$/.test(tokens[0])) {
         duration = parseInt(tokens[0], 10);
@@ -1509,7 +1516,9 @@ function executeHomeagentCmd(capability, reqId) {
             "ok",
             "screensue shown on display " +
               dispIdx +
-              (duration > 0 ? " for " + duration + "s" : "") +
+              (duration > 0
+                ? " for " + duration + "s"
+                : " (persistent until closed)") +
               ": " +
               raw.slice(0, 80),
             "",
@@ -2132,7 +2141,7 @@ function loadGuiPrefs() {
           gateway: db.gateway || "",
           token: db.token || "",
           screensueDisplay: db.screensueDisplay || "0",
-          screensueDuration: db.screensueDuration || "0",
+          screensueDuration: db.screensueDuration === undefined || db.screensueDuration === null || db.screensueDuration === "" ? "5" : String(db.screensueDuration),
           exec: db.exec || {},
           authSchedule: db.authSchedule || {},
         },
@@ -2148,7 +2157,7 @@ function loadGuiPrefs() {
       gateway: "",
       token: "",
       screensueDisplay: "0",
-      screensueDuration: "0",
+      screensueDuration: "5",
       exec: {},
       authSchedule: {},
     },
diff --git a/cmd/gui/renderer/app.js b/cmd/gui/renderer/app.js
index 5279b22..e8e5cc3 100644
--- a/cmd/gui/renderer/app.js
+++ b/cmd/gui/renderer/app.js
@@ -4992,6 +4992,13 @@ function renderDevices() {
     '</label><select id="dev-bridge-display" style="font-size:13px;padding:3px 6px;border-radius:4px;border:1px solid var(--border-color);background:var(--bg-input);color:var(--text-primary)">' +
     (dispOpts || '<option value="0">默认</option>') +
     "</select>" +
+    "<label style='font-size:13px;margin-left:8px'>" +
+    __("默认时长(秒)", "default duration(s)") +
+    '</label><input id="dev-bridge-duration" value="' +
+    escHtml(dbc.screensueDuration === undefined || dbc.screensueDuration === null ? "5" : String(dbc.screensueDuration)) +
+    '" placeholder="5，0=常驻" title="' +
+    __("screensue 默认显示秒数；0=永不超时常驻。命令带数字可临时覆盖", "screensue default seconds; 0=persistent. Command number overrides") +
+    '" style="width:70px;font-size:13px;padding:3px 6px;border-radius:4px;border:1px solid var(--border-color);background:var(--bg-input);color:var(--text-primary)">' +
     "</div>" +
     '<div style="display:flex;gap:6px;align-items:center;flex-wrap:wrap">' +
     "<label style='font-size:13px'>" +
@@ -5138,9 +5145,14 @@ async function saveBridgeChannel() {
     }
     var cfg = { enabled: true, gateway: gw };
     if (tok) cfg.token = tok;
-    // 能力配置：screensue 屏幕 / cmdrun 目录 / 沙箱
+    // 能力配置：screensue 屏幕/时长 / cmdrun 目录 / 沙箱
     var disp = document.getElementById("dev-bridge-display");
     if (disp) cfg.screensueDisplay = disp.value || "0";
+    var dur = document.getElementById("dev-bridge-duration");
+    if (dur) {
+      var dv = parseInt(dur.value, 10);
+      cfg.screensueDuration = Number.isFinite(dv) && dv >= 0 ? String(dv) : "5";
+    }
     var cwd = document.getElementById("dev-bridge-cwd");
     var sandbox = document.getElementById("dev-bridge-sandbox");
     var boxdir = document.getElementById("dev-bridge-boxdir");
diff --git a/internal/plugins/remotedevice/device.go b/internal/plugins/remotedevice/device.go
index 3a4f0a4..e7cd413 100644
--- a/internal/plugins/remotedevice/device.go
+++ b/internal/plugins/remotedevice/device.go
@@ -64,8 +64,9 @@ func (d *devicectlDevice) Tools() []agentIO.ToolDef {
 				"command 支持两类（前缀区分）：\n" +
 				"- shell-cmd: 在设备上执行原生 shell 命令，如 shell-cmd ls -la /tmp\n" +
 				"- homeagent-cmd: 调用设备端 HomeAgent 内置能力：\n" +
-				"  · homeagent-screensue <显示内容/HTML> — 用户侧屏幕弹窗显示自定义内容（带参显示，如 homeagent-screensue 会议提醒：三点开会）\n" +
-				"  · homeagent-screensue <秒> <内容> — 显示指定时长后自动关闭；不带参数则常驻\n" +
+				"  · homeagent-screensue <显示内容/HTML> — 用户侧屏幕弹窗显示自定义内容（默认 5 秒后自动关闭）\n" +
+				"  · homeagent-screensue <秒> <内容> — 指定显示时长（秒），如 homeagent-screensue 30 会议提醒：三点开会\n" +
+				"  · homeagent-screensue 0 <内容> — 永不超时，常驻显示直到用户手动关闭\n" +
 				"  · homeagent-camerasue — 抓拍单张 jpeg（结果为 base64 data URL）\n" +
 				"  · homeagent-camerasue <N秒> — 录像 N 秒 mp4（二进制分块回传，cmdresult 含 data_base64 字段）\n" +
 				"  · homeagent-speakeruse <文字> — 设备端 TTS 语音朗读文字\n" +
@@ -76,7 +77,7 @@ func (d *devicectlDevice) Tools() []agentIO.ToolDef {
 				"type": "object",
 				"properties": map[string]interface{}{
 					"device_id": map[string]interface{}{"type": "string", "description": "目标设备 ID"},
-					"command":   map[string]interface{}{"type": "string", "description": "以 shell-cmd 或 homeagent-cmd 前缀开头。如 shell-cmd pwd、homeagent-screensue 三点开会、homeagent-camerasue 5（录5秒）、homeagent-speakeruse 你好"},
+					"command":   map[string]interface{}{"type": "string", "description": "以 shell-cmd 或 homeagent-cmd 前缀开头。如 shell-cmd pwd、homeagent-screensue 三点开会、homeagent-screensue 0 重要公告、homeagent-camerasue 5（录5秒）、homeagent-speakeruse 你好"},
 				},
 				"required": []interface{}{"device_id", "command"},
 			},