How to Move a Custom GPT to Claude: Skill or Project?

OpenAI retires custom GPTs on December 11, 2026, and its own replacement turns a GPT into a ChatGPT plugin. If you’d rather move it to Claude, it becomes one of two things:

A Claude Skill, if your GPT was a way of working: your writing style, an editing checklist, a report format. A skill works in any chat, and it’s a folder of files you can keep and share.
A Claude Project, if your GPT was a place for one piece of work, such as one book or one client, and you liked having its chats together.

Either way, you move it by hand: copy the instructions, gather the knowledge files and set it up in Claude. Your past conversations don’t come with you.

What happens to custom GPTs?

They stop working on December 11, 2026. OpenAI’s replacement is the plugin, and every GPT you built gets a Migrate to plugin option under My GPTs (OpenAI).

What the migration keeps:

The GPT’s instructions, which become a skill inside the plugin.
Knowledge files, which become reference files.
Connected apps.

What it doesn’t:

Custom actions. You rebuild them separately.
The model you picked and the conversation starters.
Past conversations.
Sharing. A migrated plugin starts private, and people who used your GPT don’t get access to it.

Only published GPTs can be migrated, and after migration the original becomes read-only. OpenAI says timing and availability can vary by account and workspace. Enterprise workspaces can’t create new GPTs after October 26, and some can apply to keep them until February 11, 2027 (Virtualization Review).

The sharing part is what hurts many creators. Ethan Mollick pointed out that he could move his most-used GPT to a private plugin, “But the reason I created a GPT was for other people to use it” (Mollick on X).

Is a custom GPT closer to a Claude Skill or a Claude Project?

It depends on how you used it. Here is how they line up:

	Custom GPT	ChatGPT plugin	Claude Project	Claude Skill
How you use it	Open it and chat inside	Pick it, or ChatGPT picks it for you	Open it and chat inside	Claude loads it when your request matches
Own list of past chats	Yes	No	Yes	No
Instructions and files	Yes	Yes	Yes	Yes
Share with others	Link or GPT Store	Starts private, share by hand	Team and Enterprise plans	Share the folder; anyone can upload it

A Claude Skill is a folder with a SKILL.md file and any reference files, uploaded as a ZIP. Claude loads it when your request matches its description. Skills are available on Free, Pro, Max, Team and Enterprise plans (Claude). ChatGPT’s own replacement works the same way: your GPT’s instructions become a skill.

A Claude Project keeps its own chats, instructions and files, and has its own memory, separate from your other chats (Claude). Free accounts can create up to five Projects (Claude). On Team and Enterprise plans, you can share a Project with people in your organization (Claude).

A simple way to decide:

You used the GPT across many different chats, for things like tone, a checklist or a format. Make it a Skill.
You kept going back to the GPT for the same ongoing work, adding files as you went. Make it a Project.
You made the GPT for other people. Make it a Skill and share the folder. It’s an ordinary file, so you can post it on GitHub or send it to anyone, and they upload it to their own Claude. On a Team or Enterprise plan, a shared Project also works.

The two combine, too. A writing-style skill works inside every Project.

How do you move a custom GPT to Claude?

Start in ChatGPT, before December 11:

Open the GPT’s editor and go to Configure. Copy the full Instructions into a text file.
Note the knowledge files listed there and find your original copies.
Write down the conversation starters if you used them. They’re good test prompts later.
If the GPT used custom actions, note what each one did. Neither the ChatGPT plugin nor Claude rebuilds them for you.

As a Claude Skill

Make a folder named after your GPT, such as blog-editor.
Create SKILL.md inside it. Start with a name and a description, then paste your instructions below:
```
---
name: blog-editor
description: Edits blog drafts for clarity and tone. Use when the user asks to edit or review a blog post.
---

(Your GPT's instructions go here.)
```
Claude uses the description to decide when to load the skill, so say plainly what it’s for and when to use it.
Put the knowledge files in the same folder, and mention them in the instructions so Claude knows when to read them.
Zip the folder. In Claude, go to Customize → Skills, click +, then Create skill → Upload a skill, and upload the ZIP.
Test it with your old conversation starters.

As a Claude Project

Create a Project named after the GPT.
Paste the instructions into the Project instructions.
Upload the knowledge files to the Project.

If you already migrated the GPT to a ChatGPT plugin, the skill inside it uses the same SKILL.md format. Some business workspaces let admins download skills. We haven’t tried uploading one of those to Claude, so check that SKILL.md starts with a name and description first.

Does the skill work in Claude Code and Codex?

Yes. Coding agents read the same skill format:

Claude Code loads skills you turned on in Claude when you sign in with the same account. You can also put the folder in ~/.claude/skills/ on your computer.
Codex looks for skills in ~/.agents/skills/ for all your work, or .agents/skills/ inside a project (OpenAI).

So one skill folder works in Claude, Claude Code and Codex. If you later move again, the file moves with you, and you don’t have to rebuild anything.

Where should the GPT’s files live?

If your GPT was a writing helper, the instructions are only half of it. The other half is the material it read: past articles, notes, sources. In a GPT or a Claude Project, that material lives inside one app, and switching apps means uploading it again.

If you write with Claude Code, Codex or Antigravity, you can try our app, StashBase. It keeps that material as ordinary files in a folder on your computer:

Open the folder and chat with Claude Code, Codex or Antigravity beside your documents. You can switch agents between conversations in the same project.
PDFs, Word files and images become searchable text, so the agent finds the passage it needs.
The agent’s edits show up in the document as suggested changes you accept or reject.

You use your existing Claude or ChatGPT subscription.

If you have Gemini Gems too, see Gemini Gems Are Becoming Skills: What’s the Claude Equivalent?. For building a skill from your own writing, see How to Write with AI Without Losing Your Voice.

Frequently asked questions

Can I still use my custom GPT after migrating it to a plugin?

You can still open it, but OpenAI says a migrated GPT becomes read-only, and it stops working at retirement on December 11, 2026.

Do my conversations with a custom GPT move to Claude?

No. They don't move to the ChatGPT plugin either. Copy any answers you want to keep before December 11.

What's the Claude equivalent of a custom GPT?

A Claude Skill if the GPT was a way of working you want in any chat. A Claude Project if it was a place for one ongoing piece of work with its own chat history.