Build Your First AI Agent with n8n: The 24/7 Intern

The Intern Who Never Sleeps (And Doesn’t Steal Your Lunch)

Picture this: It’s 11 PM on a Tuesday. You’re watching your favorite show, finally relaxing, when your phone buzzes. A potential client has a question about your services. They found you online and need an answer right now. Do you:

A) Ignore it and lose the lead?
B) Drop everything and write a polite but slightly annoyed response?

Most of us pick B. Then we resent it. Then we burn out. Rinse and repeat.

Here’s the thing: you don’t need to be a 24/7 customer service rep. You need an intern. A tireless, hyper-efficient intern who never sleeps, never complains, and knows your business inside out. That’s what an AI agent is.

In this lesson, we’re building your first real AI agent. Not a chatbot toy, but a working business asset using n8n. You’ll be shocked how fast you can set this up.

Why This Matters: Your Time Is The Only Non-Renewable Resource

Manual responses are a time black hole. If you’re a freelancer, answering a single lead query can take 15 minutes. If you get 10 leads a day, that’s 2.5 hours spent on repetitive work. That’s a third of your workday gone.

An AI agent replaces:

The part-time customer service rep you can’t afford yet.
The junior sales assistant qualifying leads manually.
The frantic ‘who answered that email?’ chaos when you’re busy.

This isn’t about replacing humans. It’s about automating the work humans shouldn’t be doing. The work that drains your energy and doesn’t move the needle.

What This Workflow Actually Is

We’re building an AI Agent in n8n. Think of n8n as a visual factory floor. You have conveyor belts (workflows) and workers (AI models). We’ll connect a trigger (a new email or message) to an AI brain, which then drafts a response based on your knowledge.

What it DOES:
It listens for new inquiries (like emails), feeds the message to an AI model (like GPT-4), gives the AI your business info to answer from, and posts the drafted response back for you to approve or sends it automatically.

What it does NOT do:
It’s not a magic mind-reader. It won’t handle complex, multi-step negotiations by itself. It’s not sentient. You are still the boss; this is just your super-powered assistant.

Prerequisites: Your Toolkit

Relax. You don’t need a computer science degree. You need three things:

An n8n account: A free cloud account works perfectly. Go to n8n.io and sign up.
An OpenAI API Key: This is how we pay for the AI brain. Create an account at OpenAI, go to the API section, and make a key. Treat it like a credit card: don’t share it!
A concept: Know what you want your agent to do. Today, we’ll make a ‘Lead Responder’.

That’s it. No servers. No installs. We’re doing this live.

Step-by-Step: Build The Lead Responder Agent

Let’s build a workflow that watches your email and drafts a reply using your business voice.

Step 1: The Trigger – ‘When Mail Arrives’

First, we need n8n to know when to start working. We’ll use an email trigger.

Open your n8n dashboard. Click ‘Create Workflow’.
Click the big grey button to add your first node. Search for Email Read IMAP. Select it.
Click the node to configure it. You’ll need to connect your email account (Gmail, Outlook, etc.). n8n has guides for this. It’s like authorizing an app on your phone.
CRITICAL: Set the ‘Trigger On’ to ‘New Email’. In the ‘Criteria’ box, set a filter. This is vital. You don’t want it answering EVERY email. We only want it to look at, say, emails from your website’s contact form. Set the ‘From’ field to noreply@yourwebsite.com (or whatever the sender is).

WHY? If you don’t filter, your agent might try to answer your grandma’s birthday email. We want to contain it to business.

Step 2: The Brain – ‘Call the AI Intern’

Now we need an AI to read the email and write a response.

Click the + on the Email trigger. Search for OpenAI. Select it.
Choose the operation: Message a Model.

3. Connect your OpenAI account (paste your API key).

In the ‘Model’ field, choose gpt-4o-mini (it’s cheap and smart).
Now, the most important part: The ‘Prompt’. This tells the AI what to do. We need to give it context and the email content.

Click inside the Prompt box. On the right, you’ll see a data list. Find ‘Email Content’ (or ‘Subject’, ‘From’, etc.) and click it. It will inject the live data from the trigger node. Your prompt should look like this:

You are an expert sales assistant for a digital marketing agency called "WebGrow Inc.".

Your job is to write a concise, helpful, and friendly email reply to a potential lead. The reply should answer their question and gently ask for a quick call to discuss further.

Do not be overly salesy. Be human and direct.

Here is the incoming email:

From: {{$json.from}}
Subject: {{$json.subject}}
Body: {{$json.text}}

Step 3: The Draft – ‘Post the Result’

The AI wrote the reply. Now we need to see it. Let’s send it to Slack so you can approve it. (Or you could use an Email Sender node to auto-reply, but we’ll be safe and send it to Slack for now).

Add a Slack node after the OpenAI node.
Connect your Slack account.
Set the ‘Channel’ to a private channel only you see (e.g., #agent-drafts).

4. In the ‘Text’ field, put the AI’s reply. Click the ‘Output’ from the OpenAI node on the right to insert it.

Step 4: Activate

Click the big green ‘Active’ button at the top. That’s it. Your agent is live.

You can test it by emailing your contact form. Check your Slack in about 30 seconds. You should see a perfectly drafted reply, ready for a final check before you hit send.

Complete Automation Example: The ‘Meeting Scheduler’ Agent

Let’s level up. Here’s a more complex workflow that books meetings automatically.

Goal: A lead emails you asking for a demo. The AI agent checks your calendar using Calendly or Google Calendar API, finds a slot, and replies with a booking link. If no slots are free, it offers alternative times.

Workflow:

Trigger: Email Read IMAP (from ‘leads@’ or contact form).
Node 1: OpenAI (Response Generation):

Check the email for keywords like "demo", "meeting", or "call".
If found, write a friendly response offering to book a meeting. Do NOT offer specific times in the text. Just say you've checked availability and are ready to schedule.

Node 2: HTTP Request (Calendly/Calendar Check):

Method: GET
URL: https://api.calendly.com/event_types/... (Your Calendly API endpoint)
Headers: Authorization: Bearer YOUR_CALENDLY_TOKEN

Node 3: OpenAI (Refine Response):

The previous AI drafted the email. Now, append the booking link from the Calendly response to the email draft.

Node 4: Send Email (Gmail/Outlook node):

Send the final email back to the lead automatically.

This turns a 20-minute manual email exchange into a 30-second automated task.

Real Business Use Cases

The Local Plumber: Gets calls at 9 PM. Agent answers, asks for job details (burst pipe, clogged drain?), and texts the plumber a summary with job type and address urgency. Plumber only wakes up for emergencies.
The E-Commerce Store: Handles ‘Where is my order?’ emails. Agent connects to the Shopify API, finds the tracking number, and drafts a reply. You just click approve.

3.The Real Estate Agency: Agent monitors property portal leads. It asks the lead 3 qualifying questions (budget, timeline, location) and only passes the ‘hot’ leads to human agents.

The Freelance Writer: Agent watches for new project inquiries. It drafts a response with the writer’s portfolio links and pricing guide, cutting lead response time from hours to minutes.

5.The SaaS Founder: Agent monitors a specific Slack channel for bug reports. It categorizes the bug (‘UI’, ‘Billing’, ‘API’), tags the relevant engineer, and drafts the initial ‘We’re on it’ message to the user.

Common Mistakes & Gotchas

Going Rogue: The biggest mistake is not adding filters. Your agent starts answering internal emails or newsletters. Always filter by sender, subject line, or keywords.
API Costs: OpenAI costs money per token. A small reply costs less than a penny, but if your agent gets stuck in a loop, costs can spike. Always test with small prompts first.
The ‘Human in the Loop’ Trap: Don’t go fully auto until you’ve tested 50+ interactions and are 100% confident. Use the ‘Draft and Send’ method (like in our Slack example) first. Send it to yourself for approval.
Forgetting Context: A generic ‘Hi there’ is useless. Your prompt MUST include the incoming message data. If the AI doesn’t know what it’s replying to, it will hallucinate.

How This Fits Into a Bigger Automation System

Your agent isn’t a lone robot. It’s part of an army.

CRM Integration: After the agent drafts a reply, it can also create a new Lead in HubSpot or Salesforce automatically. Now your lead is in your funnel before you even read the email.
Voice Agents: Imagine this workflow but for phone calls. The AI answers, transcribes, and then this same agent drafts the email follow-up. The circle is complete.
Multi-Agent Workflows: One agent handles the initial reply. If the lead is qualified, a second agent kicks in to send a Calendly link. A third agent could then add them to your email newsletter sequence. Handoffs between agents are seamless.
RAG (Retrieval-Augmented Generation): For super-smart agents, you can feed it your entire company wiki or product manual. Instead of just general knowledge, it will answer technical questions perfectly because it’s reading your docs in real-time.

What to Learn Next

You now have the blueprint for creating digital employees. This is the foundational skill of the next decade. In Lesson 3, we’re going to give your agent a memory. We’ll connect a database so your agent remembers every past interaction with a customer. No more ‘Hi, who are you?’ amnesia.

The boring work is on borrowed time. Go build your first agent.

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