{"product_id":"n8n-fuel-tank-variance-investigation-sheets-gemini-slack","title":"n8n Fuel Tank Variance Investigation: Sheets, Gemini \u0026 Slack","description":"\u003ch3\u003eDetect and explain fuel tank variances automatically—using Sheets, Gemini, and Slack\u003c\/h3\u003e\n\u003cp\u003eWhen a shift closes, this \u003cstrong\u003en8n Fuel Tank Variance Investigation\u003c\/strong\u003e workflow receives a webhook, reconciles tank wet-stock in \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e, optionally calls \u003cstrong\u003eGoogle Gemini\u003c\/strong\u003e to summarize anomalies, and immediately posts investigation alerts to \u003cstrong\u003eSlack\u003c\/strong\u003e—all while logging a full audit record.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReceives a shift-close POST webhook\u003c\/strong\u003e with \u003cem\u003estation_id\u003c\/em\u003e and \u003cem\u003eshift_id\u003c\/em\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFetches reconciliation inputs\u003c\/strong\u003e from Google Sheets, including active tanks, shift tank readings, nozzle totalizer sales, deliveries, and prior audit history.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCalculates per-tank closing variance\u003c\/strong\u003e by comparing expected vs actual closing volume, applying tolerance and determining variance direction (loss or surplus).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRuns risk \u0026amp; pattern checks\u003c\/strong\u003e, including a baseline z-score, drift patterns, and identification of data gaps or possible meter\/delivery issues.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTriggers AI investigation when needed\u003c\/strong\u003e: for variances warranting review, the workflow sends the computed context to \u003cstrong\u003eGoogle Gemini\u003c\/strong\u003e to generate a \u003cstrong\u003enon-accusatory JSON\u003c\/strong\u003e investigation summary with likely causes and recommended actions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWrites results to \u003cem\u003eAudit_Log\u003c\/em\u003e\u003c\/strong\u003e in Google Sheets, including the full reconciliation record and any AI verdict\/summary.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePosts Slack notifications\u003c\/strong\u003e for tanks that need attention (alerts, critical variances, delivery shortfalls, or data gaps) and returns a JSON response to the webhook caller.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eAutomatic shift-end reconciliation for retail fuel operations where tank wet-stock must match expected sales\/deliveries.\u003c\/li\u003e\n  \u003cli\u003eFast investigation routing when z-score\/risk thresholds indicate unusual loss\/surplus or missing data.\u003c\/li\u003e\n  \u003cli\u003eAI-assisted, structured anomaly notes for auditing teams—without accusatory language.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrations\/nodes:\u003c\/strong\u003e Webhook, Google Sheets (Service Account), Slack, and optional Google Gemini.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWorkflow building blocks:\u003c\/strong\u003e if, code, merge, slack, webhook, sticky note.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eCategory: \u003cstrong\u003en8n automation workflow\u003c\/strong\u003e — designed for \u003cstrong\u003eautomation engineers\u003c\/strong\u003e and \u003cstrong\u003eSaaS operators\u003c\/strong\u003e who need reliable variance detection and audit logging with actionable alerts.\u003c\/p\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":46196346781875,"sku":"N8N-20431","price":18.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/msoEyIGDfBscdWnELoph5_WJLFZqks.png?v=1791623948","url":"https:\/\/buyflowscripts.com\/products\/n8n-fuel-tank-variance-investigation-sheets-gemini-slack","provider":"N8N Commerce","version":"1.0","type":"link"}