diff --git a/mu2edaq-dataformat-viewer.py b/mu2edaq-dataformat-viewer.py
index 32040b6..dc9804d 100755
--- a/mu2edaq-dataformat-viewer.py
+++ b/mu2edaq-dataformat-viewer.py
@@ -235,9 +235,11 @@ def _apply_config_defaults(self) -> None:
             if idx >= 0:
                 self.format_combo.setCurrentIndex(idx)
 
-        # Viewer port and protocol
+        # Viewer port and protocol.
+        # CRS_PORT_LISTEN is exported by the control room crs-app launcher.
         viewer_cfg = self._cfg.get("viewer", {})
-        port = viewer_cfg.get("port", 7755)
+        port = int(os.environ.get("CRS_PORT_LISTEN",
+                                  viewer_cfg.get("port", 7755)))
         self._port_edit.setText(str(port))
         proto = viewer_cfg.get("protocol", "TCP")
         idx = self._proto_combo.findText(proto.upper())
@@ -994,10 +996,27 @@ def _start_server(self):
             self._listen_btn.setText("Stop listening")
             self._proto_combo.setEnabled(False)
             self._set_status(f"Listening on {proto} port {port}\u2026")
+            self._start_responder(port, proto)
         except OSError as exc:
             QMessageBox.critical(self, "Error", f"Could not start server:\n{exc}")
 
+    def _start_responder(self, port, proto):
+        """Announce the listener via mu2edaq-discovery (optional dependency).
+        Started only while actually listening, stopped with the server."""
+        try:
+            from mu2edaq_discovery import Responder
+        except ImportError:
+            return
+        self._responder = Responder(
+            name="Data Format Viewer", app="dataformat-viewer",
+            port=port, scheme=proto.lower())
+        self._responder.start()
+
     def _stop_server(self):
+        responder = getattr(self, "_responder", None)
+        if responder is not None:
+            responder.stop()
+            self._responder = None
         if self._server_socket:
             try:
                 self._server_socket.close()
diff --git a/requirements.txt b/requirements.txt
index 295c285..682fe5a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 PyYAML>=6.0
 PyQt6>=6.4
+mu2edaq-discovery @ git+https://github.com/Mu2e/mu2edaq-discovery.git
diff --git a/start-mu2edaq-dataformat-viewer.sh b/start-mu2edaq-dataformat-viewer.sh
new file mode 100755
index 0000000..9e924a6
--- /dev/null
+++ b/start-mu2edaq-dataformat-viewer.sh
@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Start the Mu2e Data Format Viewer (PyQt6 GUI).
+# DISPLAY is honored from the environment so the window appears in the
+# invoking VNC session. CRS_PORT_LISTEN (exported by the control room
+# crs-app launcher) overrides the configured listen port.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PID_FILE="${CRS_HOME:-$HOME/controlroom}/log/dataformat-viewer.pid"
+mkdir -p "$(dirname "$PID_FILE")" 2>/dev/null || PID_FILE="/tmp/dataformat-viewer.pid"
+
+PYTHON="$SCRIPT_DIR/venv/bin/python"
+[[ -x "$PYTHON" ]] || PYTHON="python3"
+
+nohup "$PYTHON" "$SCRIPT_DIR/mu2edaq-dataformat-viewer.py" "$@" \
+  >> "${PID_FILE%.pid}.log" 2>&1 &
+echo $! > "$PID_FILE"
+echo "Data Format Viewer started (PID $(cat "$PID_FILE"))."
diff --git a/stop-mu2edaq-dataformat-viewer.sh b/stop-mu2edaq-dataformat-viewer.sh
new file mode 100755
index 0000000..d00f115
--- /dev/null
+++ b/stop-mu2edaq-dataformat-viewer.sh
@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Stop the Mu2e Data Format Viewer.
+set -uo pipefail
+
+PID_FILE="${CRS_HOME:-$HOME/controlroom}/log/dataformat-viewer.pid"
+[[ -f "$PID_FILE" ]] || PID_FILE="/tmp/dataformat-viewer.pid"
+
+if [[ -f "$PID_FILE" ]] && kill -0 "$(cat "$PID_FILE")" 2>/dev/null; then
+  kill "$(cat "$PID_FILE")"
+  rm -f "$PID_FILE"
+  echo "Data Format Viewer stopped."
+else
+  PIDS=$(pgrep -f "mu2edaq-dataformat-viewer.py" || true)
+  if [[ -n "$PIDS" ]]; then
+    kill $PIDS 2>/dev/null || true
+    echo "Data Format Viewer stopped (found by name)."
+  else
+    echo "Data Format Viewer is not running."
+  fi
+  rm -f "$PID_FILE" 2>/dev/null || true
+fi
+exit 0