diff --git a/monitaor-sheet-for-values/Monitor.gs b/monitaor-sheet-for-values/Monitor.gs
new file mode 100644
index 0000000..ee41629
--- /dev/null
+++ b/monitaor-sheet-for-values/Monitor.gs
@@ -0,0 +1,34 @@
+
+const ERROR_MESSAGE = "NOT_FOUND"
+const SHEET_TO_MONITOR = "your-sheet-name"
+const ALERT = "Custom alert message for this error"
+
+function main() {
+  console.time("full");
+  {
+    let sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(SHEET_TO_MONITOR);
+    assert(!findInSheet(sheet, ERROR_MESSAGE), ALERT)
+  }
+  console.timeEnd("full");
+}
+
+function findInSheet(sheet, SEARCH_FOR) {
+  let rows = sheet.getDataRange().getValues();
+  for (const row of rows) {
+    for (const cell of row) {
+      if (cell == SEARCH_FOR) {
+        console.log(`"${SEARCH_FOR}" FOUND in "${sheet.getSheetName()}"`)
+        return true;
+      }
+    }
+  }
+  console.log(`"${SEARCH_FOR}" NOT FOUND in "${sheet.getSheetName()}"`)
+  return false;
+}
+
+function assert(condition, message) {
+  if (!condition) {
+    console.error(message);
+    throw message;
+  }
+}