Automate Procurement Spend Classification in Google Sheets

Automate Procurement Spend Classification in Google Sheets with Google Gemini

Stop manually tagging procurement transactions. This n8n workflow reads pending spend records in Google Sheets, uses Google Gemini to classify each transaction against an approved taxonomy, and then either auto-updates confident results or routes uncertain cases for review via Gmail—capturing the final decision through an n8n form.

What this workflow does

• Runs daily on a schedule trigger and loads workflow settings such as the confidence threshold, review statuses, and the review recipient email.
• Builds the spend taxonomy by reading active categories from Google Sheets and incorporating approved historical classification feedback to guide Gemini.
• Classifies each pending transaction by sending Gemini the transaction context, the allowed taxonomy, and a limited set of feedback examples.
• Validates structured output, checking that the predicted category code/name exist in the active taxonomy and that required fields like confidence and reasoning are present and well-formed.
• Auto-updates when confident: if the result is valid, above the threshold, and not ambiguous, it logs to a Google Sheets audit log and updates the transaction as Classified with AI details and the final category.
• Routes for human review when needed: otherwise, it marks the row as Review Required, logs the event, and emails the reviewer via Gmail with the suggested category, confidence, and validation/ambiguity notes.
• Captures final decisions when a reviewer submits the n8n form, which the workflow then uses for the completed classification outcome.

Use cases

• Daily reconciliation of procurement spend categories across business units in Google Sheets.
• Reducing manual effort by automatically classifying straightforward transactions while escalating only ambiguous cases.
• Improving taxonomy consistency using prior human feedback embedded into Gemini prompts.

Technical details

• Integrations: Google Sheets, Gmail, Google Gemini
• Workflow logic / nodes: if, set, code, gmail, merge, sticky note
• Core automation: scheduled run, structured Gemini parsing, confidence-threshold gating, Google Sheets audit logging