diff --git a/tools/chatgui/src/message_notification.cpp b/tools/chatgui/src/message_notification.cpp
new file mode 100644
index 00000000..47cb912f
--- /dev/null
+++ b/tools/chatgui/src/message_notification.cpp
@@ -0,0 +1,127 @@
+#include "message_notification.h"
+#include "user_activity_monitor.h"
+#include "debug_ui.h"
+
+#include <QCoreApplication>
+#include <QGuiApplication>
+#include <QScreen>
+#include <QLabel>
+#include <QPushButton>
+#include <QHBoxLayout>
+#include <QVBoxLayout>
+#include <QMouseEvent>
+#include <QHideEvent>
+#include <QCloseEvent>
+
+MessageNotification::MessageNotification(QWidget* parent)
+    : QWidget(parent, Qt::Tool | Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint | Qt::WindowDoesNotAcceptFocus)
+    , m_activity(new UserActivityMonitor(this))
+{
+    setObjectName("messageNotification");
+    setAttribute(Qt::WA_ShowWithoutActivating);
+#ifdef Q_OS_MACOS
+    setAttribute(Qt::WA_MacAlwaysShowToolWindow);
+#endif
+    setFocusPolicy(Qt::NoFocus);
+    setCursor(Qt::PointingHandCursor);
+    setStyleSheet("#messageNotification { background: #353535; border: 1px solid #777; border-radius: 8px; }"
+                  "#messageNotification QLabel { color: #eee; border: none; }"
+                  "#messageNotification QPushButton { color: #eee; background: transparent; border: none; padding: 4px; }"
+                  "#messageNotification QPushButton:hover { background: #555; }");
+    auto* layout = new QVBoxLayout(this);
+    layout->setContentsMargins(14, 10, 10, 14);
+    auto* heading = new QHBoxLayout();
+    auto* title = new QLabel(QCoreApplication::translate("ChatGui", "Incoming message"), this);
+    title->setAttribute(Qt::WA_TransparentForMouseEvents);
+    heading->addWidget(title, 1);
+    auto* closeButton = new QPushButton(QStringLiteral("✕"), this);
+    closeButton->setObjectName("notificationCloseButton");
+    closeButton->setToolTip(QCoreApplication::translate("ChatGui", "Close"));
+    closeButton->setFocusPolicy(Qt::NoFocus);
+    heading->addWidget(closeButton);
+    layout->addLayout(heading);
+    m_body = new QLabel(this);
+    m_body->setTextFormat(Qt::PlainText);
+    m_body->setWordWrap(true);
+    m_body->setAttribute(Qt::WA_TransparentForMouseEvents);
+    layout->addWidget(m_body);
+    m_hideTimer.setSingleShot(true);
+    m_hideTimer.setInterval(10000);
+    m_hideTimer.setTimerType(Qt::PreciseTimer);
+    connect(closeButton, &QPushButton::clicked, this, [this] { dismiss("close-button"); });
+    connect(&m_hideTimer, &QTimer::timeout, this, [this] { dismiss("activity-timeout"); });
+    connect(m_activity, &UserActivityMonitor::activity, this, [this] {
+        if (!isVisible() || m_hideTimer.isActive()) return;
+        GUI_DEBUG("notification: first activity target=%s hide_in_ms=%d", qPrintable(m_target), m_hideTimer.interval());
+        m_hideTimer.start();
+    });
+    GUI_DEBUG("notification: initialized platform=%s hide_after_activity_ms=%d",
+              qPrintable(QGuiApplication::platformName()), m_hideTimer.interval());
+    if (QGuiApplication::platformName().startsWith("wayland"))
+        GUI_WARN("notification: native Wayland compositor controls placement and stacking; position near tray is best effort");
+}
+
+MessageNotification::~MessageNotification() {
+    m_activity->stop();
+    GUI_DEBUG("notification: destroyed target=%s visible=%d timer_active=%d",
+              qPrintable(m_target), int(isVisible()), int(m_hideTimer.isActive()));
+}
+
+void MessageNotification::showMessage(const QString& target, const QString& sender, const QString& channel, const QRect& trayGeometry) {
+    QScreen* screen = trayGeometry.isEmpty() ? nullptr : QGuiApplication::screenAt(trayGeometry.center());
+    if (!screen && parentWidget()) screen = parentWidget()->screen();
+    if (!screen) screen = QGuiApplication::primaryScreen();
+    if (!screen || screen->availableGeometry().isEmpty()) {
+        GUI_ERROR("notification: no available screen target=%s", qPrintable(target));
+        dismiss("screen-unavailable");
+        return;
+    }
+    const QRect area = screen->availableGeometry();
+    const bool replacing = isVisible();
+    m_hideTimer.stop();
+    m_target = target;
+    m_body->setText(QCoreApplication::translate("ChatGui", "New message from %1").arg(sender) + '\n' + channel);
+    setFixedWidth(qMin(360, qMax(1, area.width() - 24)));
+    adjustSize();
+    int x = area.right() - width() - 11, y = area.bottom() - height() - 11;
+    if (!trayGeometry.isEmpty()) {
+        x = trayGeometry.center().x() - width() / 2;
+        y = trayGeometry.center().y() < area.center().y() ? trayGeometry.bottom() + 8 : trayGeometry.top() - height() - 8;
+    }
+    x = qBound(area.left(), x, qMax(area.left(), area.right() - width() + 1));
+    y = qBound(area.top(), y, qMax(area.top(), area.bottom() - height() + 1));
+    move(x, y);
+    show();
+    m_activity->start();
+    GUI_INFO("notification: %s target=%s screen=%s position=%d,%d tray_anchor=%d waiting_for_activity",
+             replacing ? "updated" : "shown", qPrintable(target), qPrintable(screen->name()), x, y, int(!trayGeometry.isEmpty()));
+}
+
+void MessageNotification::dismiss(const char* reason) {
+    if (isVisible()) GUI_INFO("notification: hidden target=%s reason=%s", qPrintable(m_target), reason);
+    m_hideTimer.stop();
+    m_activity->stop();
+    hide();
+}
+
+void MessageNotification::mouseReleaseEvent(QMouseEvent* event) {
+    if (event->button() == Qt::LeftButton && rect().contains(event->pos())) {
+        const QString target = m_target;
+        dismiss("open-chat");
+        emit activated(target);
+        event->accept();
+        return;
+    }
+    QWidget::mouseReleaseEvent(event);
+}
+
+void MessageNotification::hideEvent(QHideEvent* event) {
+    m_hideTimer.stop();
+    m_activity->stop();
+    QWidget::hideEvent(event);
+}
+
+void MessageNotification::closeEvent(QCloseEvent* event) {
+    dismiss("close-event");
+    event->ignore();
+}
diff --git a/tools/chatgui/src/message_notification.h b/tools/chatgui/src/message_notification.h
new file mode 100644
index 00000000..ed0a8677
--- /dev/null
+++ b/tools/chatgui/src/message_notification.h
@@ -0,0 +1,32 @@
+/* Одно уведомление о сообщениях: не берёт фокус, ждёт активности и скрывается через 10 секунд.
+ * Новое сообщение заменяет содержимое и отменяет прежний отсчёт. activated передаёт ключ канала/DM владельцу. */
+#pragma once
+
+#include <QWidget>
+#include <QTimer>
+
+class QLabel;
+class UserActivityMonitor;
+
+class MessageNotification : public QWidget {
+    Q_OBJECT
+public:
+    explicit MessageNotification(QWidget* parent = nullptr);
+    ~MessageNotification() override;
+    void showMessage(const QString& target, const QString& sender, const QString& channel, const QRect& trayGeometry);
+    void dismiss(const char* reason);
+
+signals:
+    void activated(const QString& target);
+
+protected:
+    void mouseReleaseEvent(QMouseEvent* event) override;
+    void hideEvent(QHideEvent* event) override;
+    void closeEvent(QCloseEvent* event) override;
+
+private:
+    QString m_target;
+    QLabel* m_body = nullptr;
+    UserActivityMonitor* m_activity = nullptr;
+    QTimer m_hideTimer;
+};