Google Docs Brand Guideline Checker with n8n, Gemini & MCP

Instantly verify your Google Docs brand guidance—with AI + n8n

This n8n workflow checks a Google Docs content brief against your brand kit stored in an n8n Data Table, uses an OpenRouter-powered AI agent with MCP tools to find verifiable references, then appends a review back into the original Doc and emails an HTML report via Gmail.

What this workflow does

• Accepts a Google Doc URL via an n8n form trigger.
• Downloads the Google Doc from Google Drive as Markdown and extracts the text content.
• Loads your brand kit from an n8n Data Table (using visible entries) and concatenates it into a single reference block.
• Runs an OpenRouter-powered AI Agent with the brief text + brand-kit reference block, using MCP tools to search n8n Docs / n8n knowledge sources for verifiable links and claims.
• Generates a structured review and formats it into a Markdown report.
• Appends feedback to the original Google Doc using Google Docs.
• Converts the report to HTML and emails it via Gmail as an attachment.

Use cases

• Reviewing product messaging in Google Docs to ensure it matches your brand kit before publishing.
• Ensuring internal documentation references are consistent and claim-checked against approved sources.
• Building a repeatable brand compliance step for SaaS teams using n8n and Google Docs workflows.

Technical details

• Triggers & workflow nodes: set, merge, markdown, split out, data table, plus a form trigger.
• Google integrations: Google Drive OAuth2 (download as Markdown) and Google Docs OAuth2 (append review).
• LLM: OpenRouter API credential (optionally configurable model in the LLM step).
• MCP tooling: configurable MCP tool endpoints (example endpoints mentioned include GitBook docs MCP and Kapa MCP) with optional MCP OAuth2 credentials.
• Email delivery: Gmail node to send an HTML report attachment.

Setup note: store your brand kit in an n8n Data Table with columns: Filename, Content, FileID, IsVisible.