# Build an AI Customer Follow-Up Agent for Plumbers > Build an n8n AI agent that writes follow-up texts with care tips after each plumbing call and saves them to Google Sheets. A free, step-by-step lesson. Source: https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n · Updated 2026-11-03 · Free from Stepthrough (https://learn.ynteractive.com) ## Practice it step by step [Start the free practice](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing) [Take the free module: why it matters, practice and a quick check →](https://learn.ynteractive.com/courses/ai-for-trades/7) You do every step yourself in a practice copy of n8n. It checks your work as you go, and “Do it for me” finishes any step you get stuck on. Free, about 12 minutes, and nothing touches your real accounts. [Open full screen](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing) Free · Live now · [AI Automation for Plumbers](https://learn.ynteractive.com/content/industry/plumbing) · [n8n](https://learn.ynteractive.com/content/tool/n8n) · OpenAI · Google Sheets · ~12 min · 72 steps · Intermediate Updated November 3, 2026. Built against the tool’s current screens and checked step by step. [How we check this lesson](https://learn.ynteractive.com/content/about#how-we-check) The best time to earn a repeat plumbing customer is the day after the job. In this free lesson you build an [AI agent](https://learn.ynteractive.com/content/glossary/ai-agent) in [n8n](https://learn.ynteractive.com/content/tool/n8n) for Blue Maple Plumbing that writes a short follow-up text for each service call, with a care tip for that exact job, and saves them to Google Sheets. ## At a glance | Question | Answer | | --- | --- | | What you build | Build an AI agent for Blue Maple Plumbing that writes personalized follow-up messages after service calls and tracks them in Google Sheets — chat trigger, AI Agent, system prompt, model, memory, and the Sheets tool. | | Tools | n8n | | Time | About 12 minutes, 72 steps in 12 parts | | Level | Intermediate | | Cost | Free | | Ways to learn it | [Practice it step by step](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing), watch the video | ### The 12 parts, in short 1. Get n8n: Go to n8n.io, Enter your email, Sign up. 2. API key: Add credit first, Ten dollars is plenty, Now the key, Create a secret key, and 4 more steps. 3. New workflow: Start a new workflow. 4. Chat trigger: Add the first step, Trigger on a chat message, Back to the canvas. 5. AI Agent: Add the next node, Open the AI nodes, Add the AI Agent. 6. System prompt: Open the options, Add a system message, Write the system prompt, Back to the canvas. 7. Chat model: Give the agent a brain, Pick OpenAI, Open the credentials, Create a new credential, and 5 more steps. 8. Memory: Add memory, Simple Memory, Back to the canvas. 9. Sheets tool: Add a tool, Search for Sheets, Add Google Sheets. 10. Create the spreadsheet: Back to the canvas, Open Google Sheets, Name the spreadsheet, Type the first column header, and 6 more steps. 11. Configure Sheets: Add a credential, Create a new credential, Sign in with Google, Choose your account, and 16 more steps. 12. Test the agent: Open the chat, Ask for follow-ups, Send the message, Save to the sheet, and 1 more step. **Start here first:** [n8n AI Agent Tutorial: Save Social Media Ideas to Google Sheets](https://learn.ynteractive.com/content/n8n-ai-agent-tutorial-google-sheets). This Plumbing version follows the same build with its own example business, Blue Maple Plumbing. ## Build an AI Customer Follow-Up Agent for Plumbers: video walkthrough The whole lesson in 8:22, narrated step by step. **Simulated practice environment.** Recorded in Stepthrough’s simulated practice environment, not the live tool. Practice it yourself free at learn.ynteractive.com. 8:22 · 12 chapters · 72 steps · narrated with the lesson’s own voice-over ### Chapters Click a chapter to jump the video there. 1. [0:00 Intro: what you'll build](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=0#watch) 2. [0:11 Get n8n](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=11#watch) 3. [0:46 API key](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=46#watch) 4. [1:57 Chat trigger](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=117#watch) 5. [2:30 AI Agent](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=150#watch) 6. [2:47 System prompt](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=167#watch) 7. [3:31 Chat model](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=211#watch) 8. [4:19 Memory](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=259#watch) 9. [4:36 Sheets tool](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=276#watch) 10. [5:09 Create the spreadsheet](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=309#watch) 11. [5:59 Configure Sheets](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=359#watch) 12. [7:40 Test the agent](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=460#watch) ### Now do it yourself, free Watching is the warm-up. The interactive lesson puts you in a practice copy of n8n: you do every step yourself, it checks your work, and “Do it for me” finishes any step you get stuck on. Nothing touches your real accounts. [Practice “Build an AI Customer Follow-Up Agent for Plumbers” step by step](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing?after=video) ### Full transcript #### Intro: what you'll build [0:00](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=0#watch) Now we automate. You'll build an AI agent in n8n for Blue Maple Plumbing. It writes a follow-up after every service call and saves each one to Google Sheets. Let's build it. #### Get n8n [0:10](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=10#watch) In the last lesson you built a Custom GPT that writes plumbing quotes in your company voice. That is great for one person. But what if you want the AI to write follow-ups after every service call, save them to a spreadsheet, and let your whole office track them? That is what we are building now. First, you need an n8n account. Click get started free. [0:30](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=30#watch) Type an email address. This is just practice, so anything works — it won't actually send anything. [0:36](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=36#watch) Now click continue. In the real n8n, it sends you a six digit code, then asks for a name, a password, and an account name. Go do that in your own browser later, then come back and we will build. #### API key [0:46](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=46#watch) Your agent needs a brain, and that means an [API key](https://learn.ynteractive.com/content/glossary/api-key) from OpenAI. Go to platform dot openai dot com — that is the developer side, not ChatGPT, and it bills completely separately. Before you make a key, put some money on the account. A brand new key with a zero balance just returns errors. Click add to credit balance. [1:04](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=64#watch) Ten dollars goes a very long way. You are charged per request, not per month, and writing follow-up messages costs fractions of a cent per request. Click continue — in your own account it asks for a card at this point. [1:16](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=76#watch) Balance sorted. Now go to [API](https://learn.ynteractive.com/content/glossary/api) keys in the left menu. [1:19](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=79#watch) Click create new secret key. [1:21](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=81#watch) Name it after whatever is going to use it. Future you, staring at a list of forty keys, will thank you. I am calling this one n8n agent. [1:29](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=89#watch) Default project, all permissions — that is fine for this. Create the key. [1:33](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=93#watch) Now pay attention, because this is the only time you will ever see this key. Copy it and paste it into n8n, or into your password manager. If you lose it, you do not get it back — you delete it and make another. [1:45](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=105#watch) Click done. One last warning — this key can spend your money. Never commit it to code, never paste it into a chat, and if it ever shows up on screen while you are recording, revoke it before you publish. #### Chat trigger [1:57](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=117#watch) Now you are inside n8n. This overview page lists every workflow you have. Top right, click create workflow, and you land on an empty canvas. [2:04](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=124#watch) Every workflow needs a trigger — the thing that kicks it off. We want a chat trigger so you can talk to the agent and ask it for follow-up messages. Click add first step. [2:13](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=133#watch) A panel slides in with every way a workflow can start — manually, on a schedule, on a webhook. We want on chat message, so we can have a conversation with the agent. [2:22](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=142#watch) n8n opens the node so you can configure it. There is nothing we need to change here, so close it with the X in the top right and get back to the canvas. #### AI Agent [2:30](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=150#watch) Now we decide what happens when a message comes in. Click the plus on the right edge of the trigger. [2:35](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=155#watch) There it is — AI Agent. This is the piece that can plan and then carry out actions using whatever tools you give it. You give it the day's service calls, and it can write the follow-ups and save them to a spreadsheet — all in one step. #### System prompt [2:46](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=166#watch) Right now this agent has no personality and no orders. It does not know it works for Blue Maple Plumbing. Scroll down to options and click add option. [2:54](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=174#watch) Pick system message. This is the standing instruction — the thing the agent reads before every single request. It is where we tell it who Blue Maple Plumbing is, how the messages should sound, and how to format each follow-up. [3:06](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=186#watch) Here is the actual prompt. It describes Blue Maple Plumbing and its services, says who the customers are, sets the tone, and spells out the format to return: customer, service, follow-up message, next step, and status. It also tells the agent to use the Google Sheets tool when you ask it to save the messages. Click paste system prompt. [3:26](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=206#watch) That gives the agent everything it needs to know about Blue Maple Plumbing. Close the node. #### Chat model [3:30](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=210#watch) See that red triangle on the agent? It is complaining because it has no model. An agent can plan, but it cannot think without a language model underneath it. Click the plus under chat model. [3:40](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=220#watch) OpenAI chat model. This is where that API key finally gets used. [3:44](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=224#watch) And here is where that key you copied finally goes. Click the credential dropdown. [3:48](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=228#watch) You want create new credential, right at the bottom. [3:51](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=231#watch) Paste the key straight in. This is the one moment it matters that you copied it — remember, OpenAI never shows it to you again. [3:58](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=238#watch) Hit save. n8n tests the connection straight away, and from now on this credential is available to every node in every workflow — you only do this once. [4:07](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=247#watch) Now the model dropdown. [4:09](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=249#watch) GPT five mini. Fast, cheap, and plenty for writing follow-up messages. Do not reach for the expensive model until you have a reason. [4:16](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=256#watch) That is the brain wired in. Close it up. #### Memory [4:19](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=259#watch) Next, memory. Without this, every message starts from nothing — you could not say save those messages to the sheet, because it would not remember what messages you were talking about. Click the plus under memory. [4:29](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=269#watch) Simple memory is fine here — it keeps the recent conversation inside n8n, no database, no extra credentials. #### Sheets tool [4:36](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=276#watch) And now the good part — tools. This is what separates an agent from a chatbot. A chatbot just talks. An agent does things. We are going to give it access to Google Sheets so it can save every follow-up directly into a spreadsheet your office can track. Click the plus under tool. [4:51](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=291#watch) Google Sheets tool. Now the agent can write rows into a real spreadsheet. You would point it at a sheet with columns for customer, service, follow-up message, next step, and status — matching exactly what the system prompt tells it to generate. When you say save those messages, the agent writes each one as a row. #### Create the spreadsheet [5:09](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=309#watch) Before we set this up, we need to actually create the spreadsheet. Close this node for now — we are going to hop over to Google Sheets and make one. [5:16](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=316#watch) Switch to Google Sheets. You need to create the spreadsheet that this node will write to. [5:20](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=320#watch) First, name it so you can find it later. Click the title up top, where it says Untitled spreadsheet, and type Customer Follow-Ups. [5:27](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=327#watch) Now set up the column headers. These need to match what the system prompt tells the agent to generate. In A1, type Customer. [5:34](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=334#watch) B1 — Service. [5:36](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=336#watch) Cell C1 — Follow-Up Message. [5:38](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=338#watch) D1 — Next Step. [5:40](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=340#watch) And E1 — Status. Five columns, matching exactly what the system prompt tells the agent to generate. When the agent saves follow-ups, each one becomes a row in this sheet. [5:49](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=349#watch) The spreadsheet is ready. Switch back to n8n and connect the Google Sheets node to it. [5:54](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=354#watch) Double click the Google Sheets node to open it back up. Now we can connect it to the spreadsheet we just made. #### Configure Sheets [5:59](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=359#watch) Now we need to connect this to a real Google account. Click the credential dropdown. [6:03](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=363#watch) Create new credential — this one uses Google OAuth instead of an API key, so it is going to open a sign-in window. [6:11](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=371#watch) Click sign in with Google. This opens the Google account chooser so you can pick which account to connect. [6:16](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=376#watch) Pick the Google account you want n8n to use. This is the account that owns the spreadsheet. [6:21](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=381#watch) Google is asking what n8n is allowed to do. Check the first box — this lets n8n read and write your spreadsheets. [6:28](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=388#watch) Second box — n8n needs Drive access so it can find your spreadsheets by name. [6:33](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=393#watch) Last one — this lets Google connect to n8n as an external service. Check it. [6:38](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=398#watch) All three checked. Click continue and Google hands the credential back to n8n. [6:42](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=402#watch) Now we tell the node what to do. By default it reads rows, but we want to add rows. Click the operation dropdown. [6:49](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=409#watch) Append row. Every time the agent writes a follow-up, it adds a new row to the bottom of the sheet. [6:53](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=413#watch) Now pick the spreadsheet. Click the document dropdown. [6:56](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=416#watch) Customer Follow-Ups — that is the sheet we set up with columns for customer, service, follow-up message, next step, and status. [7:04](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=424#watch) Now pick which tab inside that spreadsheet. Click the sheet dropdown. [7:08](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=428#watch) Sheet one — it is the only tab, so this is simple. [7:11](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=431#watch) Now the columns. Each column has a purple button — click it and the AI agent figures out what data goes there. Click the purple button next to Customer. [7:18](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=438#watch) Service. Same thing — click the purple button. [7:21](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=441#watch) Follow-Up Message. [7:22](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=442#watch) Next Step. [7:24](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=444#watch) And status. Each one is now set to defined automatically by the model — the agent reads your column headers and figures out what goes where. [7:31](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=451#watch) The sheets tool is fully wired up — credential, operation, spreadsheet, sheet, and column mapping. Close it and let us test this thing. #### Test the agent [7:39](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=459#watch) Everything is connected. Time to see if it works. Click open chat at the bottom of the canvas. [7:44](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=464#watch) Give it today's service calls. Type this prompt and see what comes back. [7:47](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=467#watch) Send it off. The agent reads your system prompt, thinks about Blue Maple Plumbing, and writes three follow-ups with the exact format you asked for. [7:55](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=475#watch) It came back with three personal follow-ups — the water heater, the drain, and the sump pump — each with a care tip and a next step. Now tell it to save them to the sheet. This is where the Google Sheets tool kicks in. [8:05](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=485#watch) Send it. The agent uses the Google Sheets tool to write each follow-up as a row — customer, service, message, next step, status — exactly like the system prompt told it to. [8:16](https://learn.ynteractive.com/content/plumber-customer-follow-up-ai-agent-n8n?t=496#watch) Simple as that. We show you and you do it. Sign up below to learn AI automation for free. ## What you will build An AI agent you chat with. You type in today's calls: Linda, water heater replacement. Tom, main drain cleaning. Maria, sump pump. The agent writes three texts under 60 words each. Linda is told to give the new heater about an hour to heat up, keep the area around the tank clear, and call right away if she sees water on the floor. Tom is told to avoid flushing wipes, even the ones labeled flushable. Maria is told to pour a bucket of water into the pit before the next big storm to make sure the pump kicks on. Each one also gets a next step for the office: offer a yearly tank flush in 12 months, suggest a sewer camera inspection if the drain clogs again, offer a battery backup before storm season. When you say 'save those', every message becomes a row in a Customer Follow-Ups sheet with the status Ready to send. ## Who this is for Owners and office managers at small residential plumbing companies who know a thank-you text leads to reviews and repeat calls, but whose day is eaten up by emergencies. It follows the plumbing quote writer lesson, but stands on its own. ## What the system prompt sets up It lists Blue Maple's real services: water heaters, tankless installs, drain cleaning, sewer camera inspections, leak detection, burst pipe repairs and sump pumps. The tone is friendly and plain-spoken, like the plumber who did the job. Each message thanks the customer by first name, names the exact work, gives one practical care tip for that job and invites them to call if anything seems off. The agent must not invent prices, discounts or warranty terms, and every row is marked Ready to send. ## Why it works Care tips do two jobs. They prevent the callback you did not want, like a customer panicking that the new heater is cold after ten minutes, and they show you know your trade. The Next Step column quietly builds your future work list: tank flushes, camera inspections and battery backups. The Google Sheets tool lets the agent save that work, and memory lets it know which messages you mean. ## Care tips that fit the plumbing job The tip is the heart of every message, and it has to match the work. After a water heater swap, the worry is a customer calling at 7 p.m. because the water is still lukewarm, so the tip is to give it an hour. After a main line cleaning, the worry is the same clog in three months, so the tip is about wipes. After a sump pump replacement, the worry is finding out it does not run during the next storm, so the tip is to test it with a bucket of water first. The Next Step pairs each tip with honest future work instead of a hard sell. A yearly flush for a new tank. A camera inspection only if the drain clogs again. A battery backup before storm season, when a power outage and a full pit tend to arrive together. The system prompt keeps the messages under 60 words, so they read like a text from the plumber, not a newsletter. That is also why every row is marked Ready to send: the office can glance at the sheet and send the batch. ## How to use this in your plumbing business Swap in your own services and tips. At the end of each day, paste the calls from your schedule and let the agent draft the texts. Tips follow the calendar: freeze warnings after a winter pipe repair, sump pump tests before spring storms, a reminder about grease and food scraps after a kitchen drain call. Review the sheet, then send. Over a season, the Next Step column is a ready-made list for your slow weeks. ## Try it yourself, free Reading the steps is a start. Doing them is how it sticks. The interactive module walks you through every click in a practice copy of n8n, checks each step, and never touches your real accounts. [Start “Build an AI Customer Follow-Up Agent for Plumbers”](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing) ## Step by step: Build an AI Customer Follow-Up Agent for Plumbers All 72 steps of the interactive module, in order. In the module you watch each one, then do it yourself in a practice copy that checks your work. ### 1. Get n8n 1. **Go to n8n.io.** Start at **n8n.io**. Click **Get started free**. In the last lesson you built a Custom GPT that writes plumbing quotes in your company voice. That is great for one person. But what if you want the AI to write follow-ups after every service call, save them to a spreadsheet, and let your whole office track them? That is what we are building now. First, you need an n8n account. 2. **Enter your email.** Type any email address — this is practice, so a fake one is fine. This is just practice, so anything works — it won't actually send anything. 3. **Sign up.** Click **Continue**. n8n emails you a code, then asks for a name and password — do that part on your own and come back here. In the real n8n, it sends you a six digit code, then asks for a name, a password, and an account name. Go do that in your own browser later, then come back and we will build. ### 2. API key 4. **Add credit first.** Practice only: no card, no charge. Your agent needs a model to think with, and in the real world that is an OpenAI key with a little credit behind it. This is **platform.openai.com → Billing**. Click **Add to credit balance**. (Rather not spend anything later? New n8n accounts include free credits: pick **Gateway credits** on the model step instead of a key.) Your agent needs a brain, and that means an API key from OpenAI. Go to platform dot openai dot com — that is the developer side, not ChatGPT, and it bills completely separately. Before you make a key, put some money on the account. A brand new key with a zero balance just returns errors. If you would rather not spend anything yet, n8n gives every new account free credits. In your own n8n, you can pick gateway credits on the model step and skip the key. 5. **Ten dollars is plenty.** Ten dollars goes a long way — you pay per request, not per month. Click **Continue**. In your own account you add a card here. Ten dollars goes a very long way. You are charged per request, not per month, and writing follow-up messages costs fractions of a cent per request. 6. **Now the key.** Balance sorted. Click **API Keys** in the left menu. Balance sorted. Now go to API keys in the left menu. 7. **Create a secret key.** Click **+ Create new secret key**. 8. **Name the key.** Name it after what will use it. Type **n8n agent**. Name it after whatever is going to use it. Future you, staring at a list of forty keys, will thank you. I am calling this one n8n agent. 9. **Create it.** Leave Project and Permissions alone and click **Create secret key**. Default project, all permissions — that is fine for this. Create the key. 10. **Copy it now.** This is the only time OpenAI shows you the key. Click **Copy**, then paste it somewhere safe. Now pay attention, because this is the only time you will ever see this key. Copy it and paste it into n8n, or into your password manager. If you lose it, you do not get it back — you delete it and make another. 11. **Back to n8n.** Click **Done**. Treat that key like a password — never paste it into a chat, a repo, or a screen recording. One last warning — this key can spend your money. Never commit it to code, never paste it into a chat, and if it ever shows up on screen while you are recording, revoke it before you publish. ### 3. New workflow 12. **Start a new workflow.** This is your n8n home. Click **Create workflow** in the top right. Now you are inside n8n. This overview page lists every workflow you have. Top right, click create workflow, and you land on an empty canvas. ### 4. Chat trigger 13. **Add the first step.** Every workflow starts with a trigger. Click **Add first step…** Every workflow needs a trigger — the thing that kicks it off. We want a chat trigger so you can talk to the agent and ask it for follow-up messages. 14. **Trigger on a chat message.** The trigger panel opened on the right. Pick **On chat message** near the bottom. A panel slides in with every way a workflow can start — manually, on a schedule, on a webhook. We want on chat message, so we can have a conversation with the agent. 15. **Back to the canvas.** n8n opens the node so you can configure it. Nothing to change here — click the **×** in the top right. n8n opens the node so you can configure it. There is nothing we need to change here, so close it with the X in the top right and get back to the canvas. ### 5. AI Agent 16. **Add the next node.** Click the **+** on the right edge of the trigger node. Now we decide what happens when a message comes in. 17. **Open the AI nodes.** The **What happens next?** panel opens with categories. Click **AI** at the top. A panel opens and asks what happens next. The agent lives under AI, right at the top. 18. **Add the AI Agent.** In **AI Nodes**, click **AI Agent** — it makes a plan and carries it out using the tools you give it. There it is — AI Agent. This is the piece that can plan and then carry out actions using whatever tools you give it. You give it the day's service calls, and it can write the follow-ups and save them to a spreadsheet — all in one step. ### 6. System prompt 19. **Open the options.** The agent has no personality yet. Click **+ Add Option** under Options. Right now this agent has no personality and no orders. It does not know it works for Blue Maple Plumbing. 20. **Add a system message.** Choose **System Message**. This is the standing instruction the agent follows every time. Pick system message. This is the standing instruction — the thing the agent reads before every single request. It is where we tell it who Blue Maple Plumbing is, how the messages should sound, and how to format each follow-up. 21. **Write the system prompt.** The box starts with **You are a helpful assistant**. Replace it with the standing instruction: it is long, so just Paste in the system prompt on the box. Here is the actual prompt. It describes Blue Maple Plumbing and its services, says who the customers are, sets the tone, and spells out the format to return: customer, service, follow-up message, next step, and status. It also tells the agent to use the Google Sheets tool when you ask it to save the messages. ```text You are a customer follow-up assistant for Blue Maple Plumbing. Blue Maple Plumbing is a small residential plumbing company that handles water heater replacements, tankless installs, drain cleaning, sewer camera inspections, leak detection, burst pipe repairs, and sump pumps. The customers are homeowners we visited in the last few days. The tone should be friendly, personal, plain-spoken, and professional. Write like the plumber who did the job. Your job is to write a short follow-up text message for each service call the user gives you. Each message should thank the customer by first name, mention the exact work we did, give one practical care tip for that job, and invite them to call if anything seems off. For each service call, return: - Customer - Service - Follow-Up Message - Next Step - Status (always "Ready to send") When the user asks you to save the messages, use the Google Sheets tool to store each one. Do not invent prices, discounts, or warranty terms. Keep each message under 60 words. ``` 22. **Back to the canvas.** That tells the agent who it works for and how to format follow-ups. Close the node with the **×**. That gives the agent everything it needs to know about Blue Maple Plumbing. Close the node. ### 7. Chat model 23. **Give the agent a brain.** The agent has a red warning: it has no model. Click the **+** under **Chat Model**. See that red triangle on the agent? It is complaining because it has no model. An agent can plan, but it cannot think without a language model underneath it. 24. **Pick OpenAI.** Click **OpenAI Chat Model**. OpenAI chat model. This is where that API key finally gets used. 25. **Open the credentials.** Here is where that key goes. Click the **Credential** dropdown. And here is where that key you copied finally goes. 26. **Create a new credential.** Click **+ Create new credential** at the bottom of the list. (Free credits instead? Pick **Gateway credits** in your own n8n.) You want create new credential, right at the bottom. In your own n8n, if you skipped the key, you would pick gateway credits here instead. 27. **Paste the key.** Paste in the API key on the field to drop in the key you copied from OpenAI. This is the one moment it matters that you copied it — remember, OpenAI never shows it to you again. 28. **Save the credential.** Click **Save**. n8n tests the connection and stores the key for every future node. n8n tests the connection straight away, and from now on this credential is available to every node in every workflow — you only do this once. 29. **Open the model list.** A new credential leaves **Model** on **Select a model...**. Click the **Model** dropdown. Now the model dropdown. 30. **Choose the model.** Pick **gpt-5-mini** — fast and cheap, plenty for this. (The list is long: type **gpt-5-mini** in **Search...** to find it.) GPT five mini. Fast, cheap, and plenty for writing follow-up messages. Do not reach for the expensive model until you have a reason. 31. **Back to the canvas.** The model is wired up. Close the node with the **×**. That is the brain wired in. Close it up. ### 8. Memory 32. **Add memory.** Without memory the agent forgets each message. Click the **+** under **Memory**. Next, memory. Without this, every message starts from nothing — you could not say save those messages to the sheet, because it would not remember what messages you were talking about. 33. **Simple Memory.** Pick **Simple Memory**. It keeps the recent conversation in n8n itself. Simple memory is fine here — it keeps the recent conversation inside n8n, no database, no extra credentials. 34. **Back to the canvas.** n8n opens **Simple Memory** so you can set it up. The defaults are fine (it keeps the last 5 messages). Close it with the **×**. n8n opens simple memory so you can set it up. The defaults are fine. It keeps the last five messages. Close it with the X. ### 9. Sheets tool 35. **Add a tool.** Tools are how the agent acts on the world. Click the **+** under **Tool**. And now the good part — tools. This is what separates an agent from a chatbot. A chatbot just talks. An agent does things. We are going to give it access to Google Sheets so it can save every follow-up directly into a spreadsheet your office can track. 36. **Search for Sheets.** Google Sheets is not in **Recommended Tools**. In **Search nodes...**, type **sheets**. Google Sheets is not in the recommended tools, so search for it. 37. **Add Google Sheets.** Click **Google Sheets Tool** — read, update and write data to Google Sheets. Google Sheets tool. Now the agent can write rows into a real spreadsheet. You would point it at a sheet with columns for customer, service, follow-up message, next step, and status — matching exactly what the system prompt tells it to generate. When you say save those messages, the agent writes each one as a row. ### 10. Create the spreadsheet 38. **Back to the canvas.** Before we configure this node, we need a spreadsheet for the agent to write to. Close the node — we will come back. Before we set this up, we need to actually create the spreadsheet. Close this node for now — we are going to hop over to Google Sheets and make one. 39. **Open Google Sheets.** Click the **Google Sheets** tab to create a new blank spreadsheet. Switch to Google Sheets. You need to create the spreadsheet that this node will write to. 40. **Name the spreadsheet.** Click the title and rename it to **Customer Follow-Ups**. First, name it so you can find it later. 41. **Type the first column header.** In cell **A1**, type **Customer**. Now set up the column headers. These need to match what the system prompt tells the agent to generate. In A1, type Customer. 42. **Service.** In cell **B1**, type **Service**. B1 — Service. 43. **Follow-Up Message.** In cell **C1**, type **Follow-Up Message**. Cell C1 — Follow-Up Message. 44. **Next Step.** In cell **D1**, type **Next Step**. D1 — Next Step. 45. **Status.** In cell **E1**, type **Status**. That is all five columns — matching the system prompt. And E1 — Status. Five columns, matching exactly what the system prompt tells the agent to generate. When the agent saves follow-ups, each one becomes a row in this sheet. 46. **Back to n8n.** The spreadsheet is ready. Click the **n8n** tab to go back and connect it. The spreadsheet is ready. Switch back to n8n and connect the Google Sheets node to it. 47. **Open the Sheets node.** Double-click the Google Sheets node (n8n named it **Get row(s) in sheet in Google Sheets**) to configure it. Double click the Google Sheets node to open it back up. Now we can connect it to the spreadsheet we just made. ### 11. Configure Sheets 48. **Add a credential.** The Sheets node needs a Google account. Click the **Credential** dropdown. Now we need to connect this to a real Google account. 49. **Create a new credential.** Click **+ Create new credential** to sign in with Google. Create new credential — this one uses Google OAuth instead of an API key, so it is going to open a sign-in window. 50. **Sign in with Google.** Click **Sign in with Google** to connect your account. This opens the Google account chooser so you can pick which account to connect. 51. **Choose your account.** Click your **Google account** to continue. Pick the Google account you want n8n to use. This is the account that owns the spreadsheet. 52. **Allow Sheets access.** Google needs permission. Check **See, edit, create, and delete all your Google Sheets spreadsheets**. Google is asking what n8n is allowed to do. Check the first box — this lets n8n read and write your spreadsheets. 53. **Allow Drive access.** Check **See, edit, create, and delete all of your Google Drive files**. Second box — n8n needs Drive access so it can find your spreadsheets by name. 54. **Allow external service.** Check **Connect to an external service**. Last one — this lets Google connect to n8n as an external service. Check it. 55. **Sign in.** All three are checked. Click **Continue** to complete the Google sign-in. All three checked. 56. **Pick the operation.** Now tell n8n what to do with the sheet. Click the **Operation** dropdown. Now we tell the node what to do. By default it reads rows, but we want to add rows. 57. **Append Row.** Pick **Append Row** — the agent will add a new row for each follow-up. Append row. Every time the agent writes a follow-up, it adds a new row to the bottom of the sheet. 58. **Choose the spreadsheet.** Click the **Document** dropdown to pick which spreadsheet to write to. Now pick the spreadsheet. 59. **Customer Follow-Ups.** Click **Customer Follow-Ups** — the sheet we set up for Blue Maple. Customer Follow-Ups — that is the sheet we set up with columns for customer, service, follow-up message, next step, and status. 60. **Pick the sheet tab.** Click the **Sheet** dropdown to choose which tab inside the spreadsheet. Now pick which tab inside that spreadsheet. 61. **Sheet1.** Click **Sheet1**. Sheet one — it is the only tab, so this is simple. 62. **Map the Customer column.** Under **Values to Send**, click the **✦** button next to **Customer** — the AI agent will fill this in automatically. Now the columns. Each column has a purple button — click it and the AI agent figures out what data goes there. 63. **Map the Service column.** Click the **✦** button next to **Service**. Service. Same thing — click the purple button. 64. **Map the Follow-Up Message column.** Click the **✦** button next to **Follow-Up Message**. Follow-Up Message. 65. **Map the Next Step column.** Click the **✦** button next to **Next Step**. Next Step. 66. **Map the Status column.** Click the **✦** button next to **Status**. And status. Each one is now set to defined automatically by the model — the agent reads your column headers and figures out what goes where. 67. **Back to the canvas.** Google Sheets is fully configured. Close the node with the **×**. The sheets tool is fully wired up — credential, operation, spreadsheet, sheet, and column mapping. Close it and let us test this thing. ### 12. Test the agent 68. **Open the chat.** Time to test. Click **Open chat** at the bottom of the canvas. Everything is connected. Time to see if it works. 69. **Ask for follow-ups.** Type a prompt — give the agent today's service calls. Give it today's service calls. 70. **Send the message.** Click the **send arrow** to talk to the agent. Send it off. The agent reads your system prompt, thinks about Blue Maple Plumbing, and writes three follow-ups with the exact format you asked for. 71. **Save to the sheet.** Now tell the agent to save those messages to Google Sheets. It came back with three personal follow-ups — the water heater, the drain, and the sump pump — each with a care tip and a next step. Now tell it to save them to the sheet. This is where the Google Sheets tool kicks in. 72. **Send it.** Click the **send arrow** — the agent will use the Google Sheets tool to write the rows. Send it. The agent uses the Google Sheets tool to write each follow-up as a row — customer, service, message, next step, status — exactly like the system prompt told it to. [All free Stepthrough videos](https://learn.ynteractive.com/content/videos) ## Frequently asked questions **How much does this cost to run?** Stepthrough is free. For real use you need n8n, a Google account and an OpenAI API key; OpenAI bills per request, and the lesson suggests starting with ten dollars of credit. Check each tool's current pricing. **Will the agent offer discounts?** No. It is told not to invent prices, discounts or warranty terms. **Does it text customers automatically?** Not in this lesson. It writes the messages and saves them to Google Sheets marked Ready to send, so you review them first. **How does the interactive lesson work?** Each step is shown to you first on the left (Watch). Then you do it yourself in a practice copy on the right (Your turn), and every click is checked. If you get stuck, press Do it for me. It is a practice copy, so no real accounts are touched. **Do I need coding skills?** No. It is 69 guided steps, about 12 minutes, with the long prompts pasted for you. [Start this module free](https://learn.ynteractive.com/modules/n8n-ai-agent-plumbing) - Next in AI Automation for Plumbers: [Build an AI Emergency Request Form for Your Plumbing Company](https://learn.ynteractive.com/content/plumbing-emergency-request-form-ai-lovable-n8n) ## More n8n tutorials - [Lovable + n8n: Build a Web App with an AI Backend](https://learn.ynteractive.com/content/lovable-n8n-web-app-ai-backend): Build a contact form in Lovable and connect it to an n8n workflow — webhook trigger, AI Agent, Google Sheets, Gmail, and a Respond node that ties it all together. - [AI Receipt Extractor: Receipts to Google Sheets with n8n](https://learn.ynteractive.com/content/ai-receipt-extractor-n8n-google-sheets): Drop a photo of a receipt into an n8n chat. An AI agent reads it, pulls out the date, vendor and amount, picks a category, and adds a row to Google Sheets. - [n8n AI Email Responder: Draft Gmail Replies Automatically](https://learn.ynteractive.com/content/ai-email-responder-gmail-drafts-n8n): Build an n8n agent that watches your Gmail, reads each new customer email, and writes a reply as a draft in the same thread, ready for you to check and send. - [Daily Job Alerts: Email Each Tech Their Jobs from Google Sheets with n8n](https://learn.ynteractive.com/content/n8n-daily-job-alerts-google-sheets-gmail): Every morning at 7, n8n reads a plumbing company's jobs sheet, skips anything not assigned yet, and emails each job to the tech it's assigned to — customer, address… - [Gmail AI Triage: Auto-Label Every Email and Draft Replies](https://learn.ynteractive.com/content/gmail-ai-triage-labels-drafts-n8n): Build an n8n workflow that reads each new email, sorts it as a lead, a client or an invoice with a Text Classifier, adds the matching Gmail label, and drafts a reply to… - [A Support Agent That Answers from Your Own Docs](https://learn.ynteractive.com/content/support-agent-answers-from-your-docs-n8n): Turn an n8n chat agent into a support agent that answers only from your policies in a Google Doc, refuses what it should, and hands off to a person by email. ## From the blog - [AI Chatbot for Plumbers: What to Answer, What to Hand Off](https://learn.ynteractive.com/content/blog/ai-chatbot-for-plumbers): What an AI chatbot can do for a plumbing company: answer hours and prices, collect emergency details, book visits, and when it must hand off to a person. - [AI for Plumbing Companies: Emergency Requests, Triaged](https://learn.ynteractive.com/content/blog/ai-for-plumbing-companies): AI for plumbing companies: a request form whose AI dispatcher marks each job Emergency, Same-day or Scheduled, logs it and emails next steps. - [Automate Customer Follow-Ups After Every Service Call](https://learn.ynteractive.com/content/blog/customer-follow-up-after-service-call): Customer follow-up after a service call, done every time: an n8n AI agent drafts each message with a job-specific tip and saves it for review. [All blog posts](https://learn.ynteractive.com/content/blog) ## Visual guides This lesson’s key ideas as quick visual guides: swipe through the slides, or read the same guide as text. - [An AI agent that writes plumbing follow-up texts](https://learn.ynteractive.com/content/visual/plumber-follow-up-texts): The best time to earn a repeat plumbing customer is the day after the job. In this lesson you build an n8n agent for Blue Maple Plumbing. - [Build your first AI agent in n8n](https://learn.ynteractive.com/content/visual/agent-can-act-quote): ChatGPT answers. An agent does something with the answer. - [5 Steps to an n8n AI Agent That Saves to Google Sheets](https://learn.ynteractive.com/content/visual/5-steps-n8n-ai-agent-google-sheets): A visual guide: build an n8n AI agent that writes social media ideas and saves each one as a Google Sheets row, in 5 steps from the free lesson. [All visual guides](https://learn.ynteractive.com/content/visual) ## Free cheat sheets Print it or save the PDF: the key steps and checks from this lesson on one page, free. - [n8n AI Agent to Google Sheets Cheat Sheet](https://learn.ynteractive.com/content/cheat-sheets/n8n-ai-agent-google-sheets): A free one-page cheat sheet for an n8n AI agent: chat trigger, AI Agent, system message, OpenAI model, Simple Memory and a Google Sheets tool. - [Lovable + n8n Form Flow Cheat Sheet](https://learn.ynteractive.com/content/cheat-sheets/lovable-n8n-form-flow): A free one-page cheat sheet: a Lovable form posts to an n8n webhook, and an AI Agent logs it in Google Sheets and replies by Gmail. - [AI Glossary Cheat Sheet: 30 Terms in Plain English](https://learn.ynteractive.com/content/cheat-sheets/ai-glossary-top-30): A free one-page cheat sheet of 30 AI and automation terms in plain English: models, prompts, n8n workflows, apps and data. [All free printable cheat sheets](https://learn.ynteractive.com/content/cheat-sheets) ## Terms in this lesson Plain-English definitions, each with an example from a free lesson. A/B testing · [AI agent](https://learn.ynteractive.com/content/glossary/ai-agent) · [API key](https://learn.ynteractive.com/content/glossary/api-key) · [Append row](https://learn.ynteractive.com/content/glossary/append-row) · [Buyer persona](https://learn.ynteractive.com/content/glossary/buyer-persona) · [Chat Trigger](https://learn.ynteractive.com/content/glossary/chat-trigger) · [Customer acquisition cost (CAC)](https://learn.ynteractive.com/content/glossary/customer-acquisition-cost) · Foundation model [The full AI glossary](https://learn.ynteractive.com/content/glossary) ## Related prompts - [Case study interview questions prompt](https://learn.ynteractive.com/content/prompts/case-study-interview-questions-prompt): Plan a client interview that gets a case study's before, during and after story in their own words, with follow-up probes and… - [Email subject lines prompt](https://learn.ynteractive.com/content/prompts/email-subject-lines-prompt): Get ten honest subject lines for a finished email, each with preview text and a character count, grouped by approach so you can… - [SEO meta description prompt](https://learn.ynteractive.com/content/prompts/seo-meta-description-prompt): Write short search-result descriptions for your web pages: what the page offers, who it is for and one reason to click, inside… - [Social post ideas prompt](https://learn.ynteractive.com/content/prompts/social-post-ideas-prompt): A four-part ChatGPT prompt for social post ideas built on your services and real customer questions: platform, hook and call to… [All free prompt templates](https://learn.ynteractive.com/content/prompts) ## More terms on this topic Open-weight model · Service area · [Zero-shot prompting](https://learn.ynteractive.com/content/glossary/zero-shot-prompting) ## More prompts on this topic - [Before-and-after job post prompt](https://learn.ynteractive.com/content/prompts/before-and-after-job-post-prompt): Turn before-and-after job photos into a short social post: what was wrong, what you did and what changed, with permission first… - [Customer complaint reply prompt](https://learn.ynteractive.com/content/prompts/customer-complaint-reply-prompt): A four-part ChatGPT prompt for answering an upset customer: one real apology, every complaint answered, and only the fixes you… - [Employee newsletter prompt](https://learn.ynteractive.com/content/prompts/employee-newsletter-prompt): Turn a month of scattered updates into a short internal newsletter: news, welcomes, shout-outs and dates, with only personal… - [Good, better, best options prompt](https://learn.ynteractive.com/content/prompts/good-better-best-options-prompt): Lay out three priced options for one job, good, better and best, using only your real prices and specs, with an honest note on… - [Weekly team report prompt](https://learn.ynteractive.com/content/prompts/weekly-team-report-prompt): A ChatGPT prompt for a weekly team report: paste this week's and last week's numbers and notes, get a short owner report with no… ## Browse related tutorials [AI for Plumbing (2)](https://learn.ynteractive.com/content/industry/plumbing) · [n8n tutorials (56)](https://learn.ynteractive.com/content/tool/n8n)