diff --git a/enrichment/indexed_capture.py b/enrichment/indexed_capture.py
index 3104f19..5aa5b56 100644
--- a/enrichment/indexed_capture.py
+++ b/enrichment/indexed_capture.py
@@ -137,6 +137,9 @@ class IndexedCapture:
         ]
 
     def query_metrics(self, start_ts, end_ts, ap_bssid, ap_channel):
+        ap_channel = int(ap_channel)
+        assert isinstance(ap_channel, int), f"ap_channel must be int, got {type(ap_channel)}"
+        
         packets = self.get_packets_in_time_range(start_ts, end_ts)
 
         # Build local windowed structures
@@ -164,17 +167,17 @@ class IndexedCapture:
 
                 # Determine subtype
                 subtype = int(getattr(wlan, 'type_subtype', '0'), 16)
-                
+
                 # Always debug if resolved channel == AP's channel
                 if channel == ap_channel:
                     print(f"[DEBUG] Packet: subtype={subtype}, bssid={bssid}, sa={sa}, da={da}")
-                
+
                 # Track APs (beacons / probe responses only)
                 if subtype in (5, 8) and bssid:
                     window_aps[channel].add(bssid)
                     if channel == ap_channel:
                         print(f"[DEBUG] [AP] Adding bssid={bssid} to window_aps[{channel}]")
-                
+
                 # Track clients (always)
                 for mac in (sa, da):
                     if mac and mac != 'ff:ff:ff:ff:ff:ff':