# 167 I built an AI agent finance department (full build)

About this episode

I brought on Mike Dion, a senior corporate finance professional who has helped automate more than 100,000 hours of work out of finance processes, to walk through how to build a fully functional AI agent finance department inside N8n — from scratch, with no coding background required. We build a CFO agent named Charles, give him a team of specialist sub-agents (FP&A, Accounting, and Treasury), and watch the delegation logic in action as Charles routes questions to the right specialist instead of answering everything himself. Mike also breaks down how to use ChatGPT to write your own system prompts, why you should give the CFO a reasoning model while using cheaper models for the sub-agents, and how to publish the finished chat so your whole team can access it. By the end of this episode, you'll have everything you need to replicate this AI finance department in under 45 minutes.


Timestamps
00:00 – Intro
00:03 – What we're building: AI CFO inside N8n
00:23 – Mike's background and 100,000 hours of automation
00:52 – Why N8n over Make, Zapier, or Power Automate
02:00 – Setting up the chat trigger and naming the CFO
05:00 – Using ChatGPT to write the CFO system prompt
08:52 – Choosing the right AI model and saving on token costs
13:27 – Building the FP&A sub-agent (and what FP&A actually does)
16:36 – Adding the Accounting agent with code interpreter
19:25 – Building the Treasury agent
33:21 – Successful routing to FP&A and Treasury agents
38:19 – Publishing the chat and embedding it in Slack, Teams, or a website
39:22 – Mike's philosophy: train your team to build, don't just build for them
41:14 – Where to find Mike and his free Finance Automation Insider newsletter

Key Points

Using ChatGPT to write your own N8n system prompts is one of the fastest ways to get started — nothing knows ChatGPT better than ChatGPT itself, and what would have taken six hours of writing two years ago now takes minutes.

The delegation logic is non-negotiable. If the CFO answers questions directly instead of routing them to a specialist, you lose access to any tools or context you've connected to those specialist agents — and you pay more for it.

N8n can run completely free on a $4–5/month virtual private server, making this entire AI finance department buildable for nearly zero cost. You don't need a paid automation platform subscription.

Setting the context window to 10 (five back-and-forth interactions) is a practical default — enough for most finance questions without ballooning your API costs on every run.

You can publish the finished CFO chat and embed it directly in Slack, Microsoft Teams, or a company website. Your team sees a clean chat interface — all the N8n complexity stays invisible in the background.

Links:

F9 Finance YouTube channel — Mike's free weekly channel covering finance automation tools and builds: https://www.youtube.com/@F9Finance

F9 Finance website — corporate automation training and the free Finance Automation Insider newsletter (includes 15 five-minute finance automations you can build with tools you already have): https://f9finance.com

N8n — the free, self-hostable workflow automation tool used to build the AI CFO in this episode: https://n8n.io

Join the Build With AI community — weekly AI implementations, live coaching, and no-fluff templates built for non-technical entrepreneurs: https://www.skool.com/buildwithai/about

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FIND ME ON SOCIAL
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FIND MIKE ON SOCIAL
YouTube: https://www.youtube.com/@F9Finance
Website: https://f9finance.com