diff --git a/opencode/decisions.yaml b/opencode/decisions.yaml
index 10deff69..ac9510e4 100644
--- a/opencode/decisions.yaml
+++ b/opencode/decisions.yaml
@@ -389,3 +389,24 @@ notes:
     integrations:
       - mqtt
     status: active
+  - id: 2026-08-23-enp1s0-ipv6-static-no-gateway
+    date: 2026-08-23
+    title: enp1s0 IPv6 static-no-gateway workaround (Bell router v6 black-hole)
+    decision: "enp1s0 IPv6 deliberately Static, NO gateway: v6 internet fails fast, apps fall
+      back to IPv4. Set 2026-08-23 after Bell router's v6 route black-holed connections
+      (Tuya died). User does NOT need IPv6 beyond Matter link-local — keep this setup
+      permanently. Never disable IPv6 fully — Matter needs link-local."
+    rationale: "Tuya cloud hung on broken default v6 route; urllib3 pool exhaustion cancelled
+      setup repeatedly. Applied via shell_command.ipv6_static_nogw ->
+      /homeassistant/netfix_ipv6.sh (Supervisor network API). Verified after: Tuya loaded,
+      light back, Matter Server started. If ever reverted: Settings > System > Network >
+      enp1s0 > IPv6 = Auto."
+    entities:
+      - light.3d_printer_lights
+    files:
+      - configuration.yaml
+      - netfix_ipv6.sh
+    integrations:
+      - tuya
+      - matter
+    status: active