n8n Workflow: Compare Supplier Contracts with Gemini & Gmail

Compare Supplier Contract PDFs Automatically—with Gemini + Gmail Draft Pushback

This n8n workflow takes a newly uploaded supplier agreement PDF, extracts the commercial terms with Google Gemini, compares them against the last accepted baseline stored in n8n static data, and—when anything changes—creates a Gmail draft with pushback lines for negotiation.

What this workflow does

• Starts with an n8n Form trigger that receives a supplier PDF upload and an agreement name.
• Validates the upload, normalizes the agreement name into a consistent lookup key, and captures optional annual spend and whether this version should become the new accepted baseline.
• Uses Google Gemini (PaLM) to read the PDF and extract line prices and commercial terms as structured JSON.
• Compares the extracted terms to the stored baseline for that agreement, calculating `price deltas` and identifying terms that were added, changed, or removed.
• If the agreement name is seen for the first time, it stores the extracted terms as the baseline and shows a “baseline recorded” confirmation page.
• If nothing changed, it shows a “no change found” confirmation page.
• If changes are detected, Gemini summarizes what worsened (beyond price) and proposes pushback wording; the workflow then creates a Gmail draft and displays a results page with the full diff and whether the baseline was updated.

Use cases

• Ongoing supplier renegotiations: upload revised contract PDFs and immediately see what changed.
• Procurement review workflows: automatically flag added/removed commercial terms before approving.
• Fast negotiation drafting: generate a ready-to-edit Gmail email draft with Gemini-based pushback lines.

Technical details

• Google Gemini (PaLM): contract extraction and structured JSON term extraction + change summarization.
• Gmail OAuth2: creates email drafts when differences are found.
• n8n static data: persists the last accepted baseline per normalized agreement name.
• Workflow nodes: code, form, gmail, switch, sticky note, form trigger.