The Human Algorithm/Custom GPTs Stop Running on December 11. Not Everything You Built Will Move.
The Human Algorithm • MondayCustom GPTs Stop Running on December 11. Not Everything You Built Will Move.
OpenAI is retiring custom GPTs, and its own help page puts the last day at December 11, 2026. Your instructions and files move to the replacement, called a plugin. Custom actions, conversations, share links and drafts do not. The dates have already moved once, and the chatbot on your website is a different thing entirely.
On September 11, OpenAI told the administrators of its Enterprise workspaces that custom GPTs are being retired. The replacement is called a plugin. OpenAI’s own help page says the change “affects all ChatGPT plans,” and the last date on its timeline is December 11, 2026, next to the words “Custom GPTs stop running.”
If you have never made one, you have probably used one. If you made one for your business, you have about eleven weeks.
Where the name comes from
GPT stands for generative pre-trained transformer. It is the name of the engine, the language model OpenAI has been building since 2018. GPT-1 came out that June. GPT-3 followed in May 2020. For four years hardly anyone outside the field typed a word into any of them.
On November 30, 2022, OpenAI put a chat window in front of GPT-3.5 and called it ChatGPT. Chat, plus GPT. The engine was not new. The steering wheel was.
A year later, in November 2023, OpenAI reused the same three letters for a product. A “GPT”, with a small s when there were several, was a saved version of ChatGPT that you set up yourself. So the word now means two things: the engine under everything OpenAI sells, and the custom assistants that are being retired. Only the second one has a deadline.
What a custom GPT actually is
It is ChatGPT with your setup already loaded. You write the instructions once: who it is talking to, what tone to use, what it should refuse to do. You can attach files, such as your price list or your policies, so it answers from your material. You give it a name and a link, and hand that link to a customer or a coworker.
People used them as intake assistants, brand voice checkers and homework helpers. Small businesses used them to build a customer service desk without hiring a developer. A GPT cost nothing extra to make, so a great many were made.
Some of them also had wiring. OpenAI calls these custom actions. An action is a connection from the GPT to a service outside ChatGPT, so it can look at your booking calendar, pull an order status, or add a row to a spreadsheet. The instructions tell the GPT how to talk. The action is what lets it do something.
The dates, and the fact that they already moved
The Enterprise timeline on OpenAI’s retirement page reads like this as of September 21:
- September 11: notice sent to administrators
- September 22: target for the migration tool and a banner inside ChatGPT
- October 26: creation of new custom GPTs ends
- December 11: custom GPTs stop running
Count it out. From the notice to the shutoff is 91 days. From the banner most people will actually see to the shutoff is 80. From the day you can no longer make a new one to the day the old ones stop is 46.
Those are the Enterprise dates. For everyone else, OpenAI writes that “other plans are expected to follow the same timeline” and tells you to watch for a notice in your own account.
Every date on that page carries the label “subject to change,” and they have already changed. PCWorld reported on September 18 that new GPT creation would end on September 25. That was accurate when it was written. The page now says October 26. A second OpenAI help page, the one about creating and editing GPTs, still gives September 17 as the date for the migration tool. The company’s two pages do not agree with each other.
Check the page yourself before you plan around any of these dates. It was edited less than a day before I read it.
What moves and what does not
Think of a shop you rent inside a mall. The landlord is converting the building. You are allowed to carry your shelves, your signs and your stock to the new unit. The electrical work you paid for stays in the old wall.
According to OpenAI’s migration page, this is what gets carried across:
- Your instructions. They become what OpenAI calls a skill inside the plugin.
- Your knowledge files. They are copied over as reference files.
- Any connected apps.
This is what stays in the wall:
- Custom actions. The page says they “do not transfer through the migration workflow.” Rebuilding one may require a small piece of software that somebody has to write and host. For a business owner who built their GPT without a developer, that is the part that now needs one.
- The model you selected.
- Every existing conversation.
- Your sharing settings. The plugin starts private, so any link you handed to customers stops being the front door.
- Drafts. Only the latest published version migrates.
After you migrate, the original GPT becomes read-only.
If your GPT was instructions and a few files, the move is small. Say you have four of them and each takes two hours to migrate, test and share again. That is one working day. If your GPT had actions, you are no longer moving it. You are rebuilding it, and the 46 days between October 26 and December 11 is the whole window in which the old one still works while you do.
The chatbot on your website is a different thing
A custom GPT only ever lived inside ChatGPT. You could share a link, and the person who clicked it landed on chatgpt.com and had to log in. It could not sit on your own website.
The chat boxes you see on business websites are built another way. A developer connects the site to OpenAI’s API, which is the engine sold by the unit, and pays for what it uses. People call these wrappers. Some companies advertised that they could “put your custom GPT on your site.” What they did was rebuild your assistant on the API.
OpenAI’s list of API retirements does not mention custom GPTs. If a developer built your website chatbot, this deadline is not about it. If your “chatbot” is a chatgpt.com link in your email signature, it is.
What about a personal account?
OpenAI’s help page for creating GPTs says this: “Personal ChatGPT accounts, including Free, Go, Plus, and Pro, cannot create or publish new GPTs.” It gives no date for when that took effect. Articles online put it at August 16 or at September 19, and I could not find an OpenAI source for either.
On September 21, I opened the GPT builder on my own personal account. It loaded. The “Create a GPT” button was there, and the GPT I made before was still in the list. There was no banner and no warning. I did not press Create on a finished one to see whether it would go through.
So the help page says personal accounts cannot create a GPT, and on the same day the builder still opened on one. It may be a staged rollout, where accounts lose the button in waves. It may be documentation published ahead of enforcement. OpenAI has not said. PCWorld asked the company for details on personal plans and reported only that the retirement timeline it had was for Enterprise.
What to do this week
Open ChatGPT, go to your GPTs, and open each one you rely on. Copy the instructions into a plain document on your own computer. Download every knowledge file you uploaded, or find the originals. Write down every action it has and what service each one talks to. Write down who you gave the link to.
That list takes an hour and it is yours no matter what OpenAI does next. The instructions are the part with real value, and they are plain text. They will work in a plugin, in a ChatGPT Project, or pasted into a different assistant from a different company.
December 11 is a Friday. October 26 is a Monday.
Forward → Upward ↑ Onward ↗︎
Mstimaj
Sources and Further Reading
Comments
No comments yet. Yours can be the first.