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GPT-5.1 is out
Plus: the best agent SDKs, how to build a simple cloud-based agent, and more
Michael Cunningham
November 13, 2025
In partnership with
Edition 136 | November 13, 2025
My time spent scrolling Instagram definitely at least doubled when I learned to use Claude code.
Welcome back to Building AI Agents, your biweekly guide to everything new in the field of agentic AI!
In today’s issue…
GPT-5.1 is rolling out today
A practical guide to building a cloud-based agent
We’re all doing MCP wrong
The best agent SDKs
Using agents to simulate societies
…and more
🔥 IN CASE YOU MISSED IT
Readers’ favorite items from the past week
‼️ ESSENTIAL NEWS
OpenAI’s latest model is now rolling out to ChatGPT users, though some may get it sooner than others over the next few days. As predicted in this Monday’s Spotlight, it’s more of an evolution than a revolution, with its main improvements being a warmer and more conversational style and a tendency to spend less time thinking on easier problems and more time on harder ones.
For agent builders, the model’s Instant and Thinking versions will be available in the OpenAI API beginning later this week.
🤖 AGENT OF THE WEEK
👋 Welcome back to Agent of the Week!
Small business owners shouldn't need a degree in inbox management.
My parents run a restaurant. Every week, their inbox fills up with invoices from suppliers, utilities, vendors—dozens of them. Finding the right one, downloading the PDF, remembering the due date... it eats up hours they don't have.
So I built them an agent.
Meet Ledger, their AI invoice assistant.
Every morning, Ledger wakes up and gets to work. It scans their email, finds every invoice, extracts the vendor name, amount, and due date, then uploads the PDF to Google Drive. Finally, it logs everything in a Google Sheet with a direct link to the file.
My parents open one sheet. They see everything they owe, when it's due, and where to find it. That's it.
No more inbox archaeology. No more "where did I save that?" No more stress.
They have their own AI employee now—one that works 24/7 and never takes a day off. It makes their life just a little easier.
And honestly? That's what the next few decades will be about.
Let me show you how to build one.
🧠 How It Works
1. Schedule Trigger → Daily Inbox Scan
Every morning, Ledger wakes up at 9am and checks your Gmail for new invoices
2. Gmail → Extract Invoice Attachments
Ledger pulls the PDF attachments from supplier emails
3. Mistral AI → OCR & Text Extraction
Ledger uses Mistral AI (the best OCR tool) to read and extract all text from the PDF
4. Invoice Analyzer Agent → Structure the Data
The AI agent processes the extracted text and identifies the vendor name, amount, due date, and invoice number, formatting it into clean structured data
5. Google Drive → Store the PDF
Ledger uploads the invoice to a dedicated folder in your Drive
6. Google Sheets → Log Everything
Ledger adds a new row with the vendor, amount, due date, and a direct link to the PDF
7. Text Reply → Send Confirmation
Ledger send you a text saying a new invoice has been catalogued
This agent is perfect if you:
Get buried in invoices every week and waste time finding them
Want to stop missing due dates and late payment fees
Or just want your own AI employee working 24/7 so you don't have to
Want to build Ledger yourself? I walk through the full setup step-by-step inside our Building AI Agents Community.
Till next week,
✌️ AP
🤝 WITH THE CODE
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