OpenAI is retiring custom GPTs. They’re due to stop running on 11 December 2026. If your business leans on one, nothing breaks today, but it does need a new home before Christmas. I’d move most NZ small businesses to an AI agent: an assistant that knows your business and can also do things, like update a spreadsheet or draft the reply that’s been sitting in your inbox since Tuesday.
What happens to my custom GPT after December 2026?
It stops working. OpenAI has it scheduled for 11 December 2026, and until then the GPT you use today carries on as normal. OpenAI offers a way to migrate, but custom actions, the bits that connect your GPT to other tools, don’t come along for the ride and need rebuilding. That’s the part I do. I move NZ small businesses from a custom GPT to an AI agent that does the same job and plugs into the tools they already use, like Xero, Gmail or Google Sheets.
What is a custom GPT?
A custom GPT is a version of ChatGPT set up to work for one business. It knows your products and how you talk to your customers. You type a question and it answers like someone who read your whole Google Drive over the weekend and turned up on Monday knowing where everything is. An AI agent does the same and can act on what it knows, which is why agents are taking over from custom GPTs.
What can a custom GPT actually do?
Whatever you set it up for, and it gets better the narrower the job. Good jobs for one are answering customer questions on your website, finding the document nobody on your team can find, drafting emails and proposals in your voice, or screening enquiries before they reach your phone. One built to answer questions about your service packages beats one built to “help with business generally” every time. An AI agent does all of that and then files the enquiry in your CRM as well.
How is it different from just using ChatGPT?
ChatGPT knows the world. A custom GPT knows your business. If you’ve ever typed a paragraph of background into ChatGPT before getting to the actual question, that paragraph is what a custom GPT saves you. Every time, forever. Well, until 11 December. More on what that looks like on my AI services page.
How long does it take to build?
A simple assistant doing one job for one audience takes a few days to build and test. Hooking it up to your CRM or booking system takes longer. I scope every AI project after a first conversation, because how long it takes comes down to what you want it to do, and I’d rather give you a real number than a hopeful one.
What does it cost to get one built in NZ?
An assistant built on your documents and FAQs is a small project. One that talks to your other tools and handles live enquiries on your website is a bigger one. The quickest way to a real number is to describe the job. “I want AI in my business” is hard to price. “I want something that answers questions about my services on my website without me” is something I can scope and price.
Can a custom GPT connect to my other tools?
Yes. Your website, CRM, booking system and Google Drive are the usual suspects, linked up through APIs or tools like Zapier and Make. Some connections take minutes and some are a bit of a faff, but most of what NZ small businesses run on, like Xero, Calendly, HubSpot, Shopify and Google Workspace, connects fine. AI agents are stronger here, because connecting to your tools is what they’re built for.
Is a custom GPT the only option, or are there alternatives?
There are a few. Google Gemini has Gems, the same idea built on Gemini. Microsoft Copilot has its own version for businesses on Microsoft 365. And with custom GPTs on their way out, an AI agent is where I’d look first. Which one fits comes down to the tools you already use and where you want the assistant to live.
What if I already use ChatGPT, why would I need this?
Using ChatGPT well means you’re there every time, typing. An assistant built for your business does the same job the same way while you’re off doing something else. If you’re already getting value from ChatGPT and you’re tired of re-explaining yourself every session, that’s usually the moment.
Dear John is me, Marjan Crabtree, in Paraparaumu on the Kapiti Coast. I build AI agents and automations for small businesses across New Zealand, and until December, the odd custom GPT rescue. See what I build