Gmail AI Reply Draft Workflow: OpenAI, Slack Approval, Sheets Log

Draft smart Gmail replies in minutes—then get human approval in Slack

This n8n workflow automatically monitors your Gmail INBOX, uses OpenAI (gpt-4o-mini) to determine whether a reply is needed, drafts a grounded response using Cognee context, saves it as a Gmail draft, and routes an approval request to Slack—with every decision logged to Google Sheets.

What this workflow does

• Runs every minute when a new email arrives in the Gmail INBOX.
• Skips automated senders (e.g., no-reply, mailer-daemon) to avoid unnecessary processing.
• Uses OpenAI (gpt-4o-mini) to classify whether the email needs a human reply.
• For emails requiring a response, an OpenAI agent (also gpt-4o-mini) performs Cognee search to retrieve relevant company context and generate a grounded reply draft.
• Creates a Gmail draft in the same conversation thread and posts a preview to Slack for approve/reject.
• Logs approval status, timestamp, sender, subject, and the draft text to Google Sheets.
• If any step fails, it formats the error details and sends an alert to Slack.

Use cases

• SaaS teams routing inbound requests to draft responses for faster turnaround.
• Support or sales inbox management where you want AI-assisted replies with human review.
• Operators who need an audit trail of what was approved and why, stored in Google Sheets.

Technical details

• Gmail: monitors INBOX, creates draft replies in-thread.
• OpenAI: classifies “reply needed” and generates the draft using gpt-4o-mini.
• Cognee: retrieves grounded knowledge from your configured dataset (e.g., cognee_3rd_workflow_dataset).
• Slack: posts approval previews and sends error alerts.
• Google Sheets: records approval outcomes and draft content.
• Core n8n logic includes if, set, and no op behavior plus supporting nodes like sticky note.

Perfect for n8n users and automation engineers who want an SEO-friendly, approval-based Gmail AI reply workflow with grounded context and reliable logging.