Tired of bloated “AI agent” tutorials that throw Zapier, LangChain, and endless hacks at you?
Here’s the leanest way to build real AI agents today — using just one mega prompt and n8n.

By the end of this guide, you’ll have your first AI agent running.

What You’ll Need

  • A ChatGPT or Claude account
  • A free n8n account (cloud or self-hosted)
  • An OpenAI or Anthropic API key

That’s it. No extra libraries or hacks.

Step 1: Open ChatGPT or Claude

Fire up ChatGPT or Claude and paste in this mega prompt (you’ll use it every time you want to create a new agent).

<role>
You are a senior automation architect...
</role>

<task>
Guide me step-by-step to build an AI-powered agent in n8n. 
The agent’s purpose is: {$AGENT_PURPOSE}
</task>

<requirements>
1. Scope goals + inputs/outputs
2. Design architecture
3. Recommend n8n nodes
4. Explain config
5. Provide code snippets
6. Add retry + error handling
7. Show data storage (DB, Sheets, etc.)
8. Walk through API setup
</requirements>

<output_style>
Be hands-on. Copy-paste ready configs. 
</output_style>

<expandability>
Suggest workflow chaining, webhooks, CRMs, Slack, vectors. 
</expandability>

Replace {$AGENT_PURPOSE} with the agent you want to build.

👉 Example: “Summarise new Reddit posts and send them to a Telegram channel.”

Step 2: Let GPT/Claude Do the Heavy Lifting

Within seconds, you’ll get back:

  • A full workflow architecture
  • Suggested n8n nodes + triggers
  • Code snippets for custom functions
  • Built-in error handling + retries

Example output for a Reddit → Telegram summariser:

  1. Reddit Node → Pull posts from r/technology every hour
  2. OpenAI Node → Summarise each post in 3 sentences
  3. Telegram Node → Send to your Telegram group
  4. Error Trigger → Retry failed messages + log in Google Sheets

Step 3: Rebuild in n8n

Open n8n and recreate the workflow.
Here’s what that Reddit → Telegram agent looks like visually:

Reddit Trigger → OpenAI Summariser → Telegram Send
          ↘ Error Handler → Google Sheets Logger

Every step is drag-and-drop. GPT gives you configs you can literally copy-paste.

Step 4: Add Your API Keys

Paste each key into n8n’s node credentials manager.

Step 5: Test & Deploy

Hit Execute Workflow.
If everything’s wired up correctly, you’ll see new Reddit posts summarised and pushed into your Telegram channel.

n8n handles retries, so if Reddit’s API is flaky, your agent won’t die.

Step 6: Expand (Optional)

Once you’ve got your first agent running, scale it:

  • Chain multiple workflows with webhooks
  • Store logs in Google Sheets, Airtable, or PostgreSQL
  • Route leads into HubSpot or Salesforce
  • Add reasoning with vector databases
  • Trigger via Slack, Discord, or Email

Real Examples I’ve Built

Using this exact method, I’ve built:

  • ✅ Reddit → Claude → Telegram curator
  • ✅ Lead scoring & routing agent
  • ✅ Auto-reply email summariser
  • ✅ Notion → Twitter daily poster

Each took under an hour.

Why This Works

  • GPT acts like a senior engineer → no guesswork
  • n8n is flexible & visual → no lock-in like Zapier
  • Claude/ChatGPT provide reasoning → beyond simple triggers

Final Thoughts

You don’t need Zapier, LangChain, or over-engineered frameworks.
Just one mega prompt + n8n = infinite agents.

Skip the bloat. Build your first agent today.