diff --git a/scripts/ui-drift-audit.sh b/scripts/ui-drift-audit.sh
index 04cc518..da9cb06 100644
--- a/scripts/ui-drift-audit.sh
+++ b/scripts/ui-drift-audit.sh
@@ -9,12 +9,61 @@ fi
 ROOT="$(git rev-parse --show-toplevel)"
 cd "$ROOT"
 
+# Detect whether ripgrep is available. Fall back to grep so the audit cannot
+# silently pass on hosts without rg (which was hiding regressions until now).
+if command -v rg >/dev/null 2>&1; then
+  SEARCH_BACKEND="rg"
+else
+  SEARCH_BACKEND="grep"
+  echo "[ui-drift-audit] note: ripgrep not found, falling back to grep" >&2
+fi
+
+# Build a search command that maps rg --glob exclusions to grep --exclude.
+search() {
+  local pattern="$1"
+  shift
+  if [[ "$SEARCH_BACKEND" == "rg" ]]; then
+    rg -n "$pattern" "$@" --glob '!**/*.test.*' || true
+  else
+    # grep equivalent: -rnE with --exclude for test files. Translate
+    # rg-style --glob '!path' arguments into grep --exclude entries so the
+    # caller's exclusions (e.g. the @bytelyst/ui adapter file) still apply.
+    local targets=()
+    local extra_excludes=()
+    while [[ $# -gt 0 ]]; do
+      case "$1" in
+        --glob)
+          local glob_arg="${2:-}"
+          if [[ "$glob_arg" == "!"* ]]; then
+            local glob_path="${glob_arg#!}"
+            # grep --exclude matches against the basename, so reduce the
+            # exclusion to a filename pattern. If callers exclude paths
+            # like 'web/src/components/ui/Primitives.tsx', the basename
+            # 'Primitives.tsx' is the exclusion key.
+            extra_excludes+=("--exclude=$(basename "$glob_path")")
+          fi
+          shift 2
+          ;;
+        *)
+          targets+=("$1")
+          shift
+          ;;
+      esac
+    done
+    grep -rnE "$pattern" "${targets[@]}" \
+      --include="*.ts" --include="*.tsx" --include="*.js" --include="*.jsx" \
+      --exclude="*.test.*" --exclude="*.spec.*" \
+      --exclude-dir=node_modules --exclude-dir=.next \
+      ${extra_excludes[@]+"${extra_excludes[@]}"} 2>/dev/null || true
+  fi
+}
+
 report() {
   local title="$1"
   local pattern="$2"
   shift 2
   local matches
-  matches="$(rg -n "$pattern" "$@" --glob '!**/*.test.*' || true)"
+  matches="$(search "$pattern" "$@")"
 
   echo "=== $title ==="
   if [[ -z "$matches" ]]; then