diff --git a/relay.py b/relay.py
index 9c8e201..cb8009e 100644
--- a/relay.py
+++ b/relay.py
@@ -184,11 +184,18 @@ class Relay:
             msg_type = msg.get("type")
 
             if msg_type == "hello":
-                # Respond with hello ack
+                # Respond with proper hello — must match xiaozhi protocol
                 resp = {
                     "type": "hello",
-                    "session_id": "relay-session",
+                    "version": 1,
                     "transport": "websocket",
+                    "session_id": "relay-session",
+                    "audio_params": {
+                        "format": "opus",
+                        "sample_rate": ESP_SAMPLE_RATE,
+                        "channels": 1,
+                        "frame_duration": ESP_FRAME_MS,
+                    },
                 }
                 await self.ws.send(json.dumps(resp))
                 log.info(f"ESP32 hello: {msg.get('audio_params')}")