Custom GPTs are being retired: how to keep your instructions and use them in any AI

By Elias, developer of XXL Prompt Manager · Updated 29 September 2026

OpenAI announced on September 11, 2026, that custom GPTs are being retired and replaced by plugins. The scheduled retirement date is December 11, 2026, and OpenAI says timing and migration availability can vary by account and workspace. Before your GPTs change, copy their instructions somewhere you control. Instructions are plain text, so you can keep using them in a migrated plugin, in another ChatGPT chat, or in Claude and Gemini.

What is changing, and when

Check the notices in your own ChatGPT account for the date that applies to you.

What moves to a plugin, and what doesn't

When you migrate a GPT, OpenAI turns it into a plugin:

• Moves over: the GPT's instructions (they become a skill inside the plugin), knowledge files (they become plugin reference files) and connected apps.
• Doesn't move over: your past conversations with the GPT, the selected model, custom actions (these may have to be rebuilt as an app or a custom MCP server), and sharing settings.

OpenAI also warns that a migrated plugin may respond differently than the GPT did. That is the main reason to keep your own copy of the instructions: if the plugin's answers drift, you can compare against the original and fix it.

Step 1: copy your GPT's instructions

For every GPT you built:

1. In ChatGPT, open My GPTs and click Edit on the GPT.
2. Switch to the Configure tab.
3. Select everything in the Instructions field and copy it.
4. Also note the conversation starters and the names of any knowledge files and actions.

Do this even if you plan to migrate. It takes a minute per GPT and gives you a version that no platform change can take away.

Step 2: keep the instructions as plain text you own

Where you store them matters less than being able to find and reuse them. A notes app works. If you use AI chats every day, a prompt library is faster, because the instructions sit one click away in the chat you're already in.

In XXL Prompt Manager (a free Chrome extension we make), you save each GPT's instructions as a prompt, put them in a folder such as "Custom GPT backups", and copy them into ChatGPT, Claude, Gemini or 8 other AI chat sites with one click. Parts that change from use to use can become [variables], for example, [client] or [tone]. The free version needs no account and stores prompts only in your browser.

If a GPT was mainly background instructions ("you are my editor for…"), save them as a profile instead: the extension then adds them to every prompt you copy, in any of the 11 chats, much like the GPT did inside ChatGPT. With Pro you keep up to 20 profiles, one per former GPT, and switch between them with one click. More in our guide to custom instructions for every AI chat.

Step 3: reuse the instructions anywhere

Custom GPT instructions are just a long system-style prompt, so they work outside ChatGPT too:

• In any chat: paste the instructions as your first message, followed by "Confirm you understand, then wait for my first request."
• In Claude: put them in a Project's custom instructions.
• In Gemini: paste them into a Gem's instructions.
• In a migrated ChatGPT plugin: compare its answers with the original using the test prompt below.

These three prompts help with the move. Copy them one by one, or download them all at the end of the section.

Below are the instructions for a custom GPT I built. Rewrite them as one self-contained prompt I can paste at the start of any AI chat (ChatGPT, Claude, Gemini).

Requirements:
- Keep every rule, constraint and formatting requirement.
- Replace anything that only works inside a GPT (knowledge files, actions, "use your browsing tool") with a short note in square brackets that tells me what I need to paste in myself.
- Put the parts that change from use to use in square brackets, each with a short lowercase name.
- End with: "Confirm you understand, then wait for my first request."

Instructions:
[GPT instructions]

I migrated a custom GPT to a ChatGPT plugin and want to check that it still behaves the same.

Here are the original GPT instructions:
[GPT instructions]

Write 8 test requests that cover the most important rules in these instructions, including at least 2 edge cases. For each test, describe in one sentence what a correct answer must contain. Give me the result as a table: test request | what a correct answer contains.

I want to recreate a custom GPT in [target AI]. Here are its instructions:
[GPT instructions]

1. List what [target AI] can do natively for each part of these instructions, and what I would have to do by hand (for example, uploading reference files at the start of a chat).
2. Rewrite the instructions for [target AI], keeping the same behavior and tone.
3. Suggest three short first messages I can use to test the result.

Frequently asked questions

Will my GPT stop working on December 11, 2026?

That is the scheduled date. OpenAI says timing can vary by account and workspace, and Enterprise workspaces can get approved deferrals until February 11, 2027. Your ChatGPT account shows the notices that apply to you.

Do my conversations with a GPT move to the plugin?

No. Existing conversations do not migrate, and neither does the model you selected for the GPT.

Is migration automatic?

No. The GPT's creator (or a workspace admin) starts the migration from My GPTs. Instructions, knowledge files and connected apps move over; custom actions may need to be rebuilt.

What's the safest way to keep my GPT's behavior?

Copy the instructions as plain text before you migrate, keep a few typical requests you used it for, and test the plugin against them afterwards. Plain text also works in Claude and Gemini if you ever want to switch.

Sources

• OpenAI Help Center: Custom GPT retirement and migration FAQ
• Virtualization Review: OpenAI to Retire Custom GPTs, Replace Them with Plugins (September 28, 2026)
• mixed-news.com: OpenAI is retiring custom GPTs, here's what carries over to plugins