diff --git a/CLAUDE.md b/CLAUDE.md
index 8068233..0b8d8ba 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -41,7 +41,7 @@ docker run -p 8050:8050 sdr-docker
 ## API endpoints
 
 ### RX
-- `GET /api/status` — system status, RX metrics, peak power
+- `GET /api/status` — system status, RX metrics, peak power; includes `sdr_connected` (bool) indicating whether the SDR hardware is currently open
 - `GET /api/packets` — poll-and-drain decoded packets (NDJSON)
 
 ### TX
diff --git a/src/stream_web/app.py b/src/stream_web/app.py
index 136bd99..baa98c1 100644
--- a/src/stream_web/app.py
+++ b/src/stream_web/app.py
@@ -300,6 +300,7 @@ def api_status():
                 cs_stats[chip]["avg_rs_corr_pct"] = round(sum(pcts) / len(pcts), 1)
 
         return jsonify(
+            sdr_connected=state.rx_connected.is_set(),
             devices=dev_list, stats=stats,
             td_img=td_b64, td_running=state.td_running,
             td_device_id=state.td_target_ntw_id,
diff --git a/tests/test_mock_sdr.py b/tests/test_mock_sdr.py
index 108e905..61b3759 100644
--- a/tests/test_mock_sdr.py
+++ b/tests/test_mock_sdr.py
@@ -201,3 +201,11 @@ def test_api_status_device_fields(self):
         assert isinstance(dev["seq_nums"], list)
         assert isinstance(dev["max_energy_dB"], (int, float))
         assert "chipset" in dev
+
+    def test_api_status_reports_sdr_connected(self):
+        client = self._client()
+        # rx_connected reflects whether the SDR hardware is currently open.
+        state.rx_connected.set()
+        assert client.get("/api/status").get_json()["sdr_connected"] is True
+        state.rx_connected.clear()
+        assert client.get("/api/status").get_json()["sdr_connected"] is False