diff --git a/rdp-proxy/Dockerfile b/rdp-proxy/Dockerfile
index 40d011c..4616c17 100644
--- a/rdp-proxy/Dockerfile
+++ b/rdp-proxy/Dockerfile
@@ -2,7 +2,7 @@ FROM debian:bookworm-slim
 
 ENV DEBIAN_FRONTEND=noninteractive
 
-RUN apt-get update && apt-get install -y --no-install-recommends     python3     xvfb     x11vnc     freerdp2-x11     novnc     websockify     ca-certificates     fonts-dejavu-core     && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y --no-install-recommends     python3     xvfb     x11vnc     freerdp2-x11     novnc     websockify     xdotool     ca-certificates     fonts-dejavu-core     && rm -rf /var/lib/apt/lists/*
 
 COPY entrypoint.sh /entrypoint.sh
 COPY manager.py /manager.py
diff --git a/rdp-proxy/manager.py b/rdp-proxy/manager.py
index 43992a1..b7e4bad 100644
--- a/rdp-proxy/manager.py
+++ b/rdp-proxy/manager.py
@@ -70,6 +70,35 @@ def _monitor_loop():
 
 
 threading.Thread(target=_monitor_loop, daemon=True).start()
+def _anti_idle_loop():
+    """Send Shift key every 30s while xfreerdp is connected to prevent screen lock."""
+    while True:
+        time.sleep(30)
+        with _lock:
+            active = _should_be_connected and _proc is not None and _proc.poll() is None
+        if not active:
+            continue
+        try:
+            # Try to send Shift to xfreerdp window
+            result = subprocess.run(
+                ["xdotool", "search", "--name", "FreeRDP", "key", "shift"],
+                env={**os.environ, "DISPLAY": DISPLAY},
+                capture_output=True, timeout=5,
+            )
+            if result.returncode != 0:
+                # Fallback: mousemove
+                subprocess.run(
+                    ["xdotool", "mousemove", "--sync", "960", "540"],
+                    env={**os.environ, "DISPLAY": DISPLAY},
+                    capture_output=True, timeout=5,
+                )
+        except Exception as e:
+            log.debug("anti_idle error: %s", e)
+
+
+threading.Thread(target=_anti_idle_loop, daemon=True).start()
+
+
 
 
 class Handler(BaseHTTPRequestHandler):