diff --git a/sim/cluster0/scripts/compose-lab-backend.sh b/sim/cluster0/scripts/compose-lab-backend.sh
index 1f1227d..9d8a160 100755
--- a/sim/cluster0/scripts/compose-lab-backend.sh
+++ b/sim/cluster0/scripts/compose-lab-backend.sh
@@ -69,6 +69,12 @@ if [ -d "${WS}/ac-platform-web/assets" ]; then
   fi
 fi
 
+if [ -f "${WS}/ac-be-auth/public/assets/js/two_factor.js" ]; then
+  log "sync ac-be-auth two_factor.js"
+  mkdir -p "${COMPOSED}/public/assets/js"
+  cp -a "${WS}/ac-be-auth/public/assets/js/two_factor.js" "${COMPOSED}/public/assets/js/"
+fi
+
 overlay_src ac-platform-php
 overlay_src ac-ms-identity
 overlay_src ac-ms-rbac
@@ -249,6 +255,39 @@ return [
 ];
 PHP
 
+BUILD_CFG="${WS}/ac-be-builder/config/config.php"
+if [ -f "${COMPOSED}/config/config.php" ]; then
+  log "write ac-be-builder config.php (shared cluster session + DB)"
+  cat > "$BUILD_CFG" <<'PHP'
+<?php
+$config = require '/var/www/ac/composed/backend/config/config.php';
+$config['app_name'] = 'Android Cast Builder';
+$config['base_path'] = '/app/androidcast_project/build';
+$config['links'] = [
+    'hub' => '/app/androidcast_project/',
+    'crashes' => '/app/androidcast_project/issues/',
+    'git' => '/app/androidcast_project/git/',
+    'tickets' => '/app/androidcast_project/issues/?view=tickets',
+];
+$config['build'] = array_merge([
+    'docker_image' => 'androidcast-ci:latest',
+    'docker_bin' => '/usr/bin/docker',
+    'ci_version' => '00.01.00.1000',
+    'repo_root' => '/var/www/ac/workspace',
+    'artifacts_root' => '/var/www/ac/broadcast/builds',
+    'ota_mount' => '/var/www/ac/broadcast/ota-artifacts',
+    'ota_base_url' => 'https://apps.f0xx.org',
+    'runner_script' => '/var/www/ac/workspace/ac-scripts/docker-build-runner.sh',
+    'isolate_source' => true,
+    'git_clone_depth' => 1,
+    'pipeline_config' => '/var/www/ac/workspace/ac-scripts/build.config.yml',
+    'default_channels' => ['stable', 'staging', 'dev', 'nightly'],
+], $config['build'] ?? []);
+return $config;
+PHP
+  chown nginx:nginx "$BUILD_CFG" 2>/dev/null || true
+fi
+
 if command -v composer >/dev/null 2>&1; then
   log "composer dump-autoload (optional)"
   cat > "${COMPOSED}/composer.json" <<'JSON'