Guide ยท updated 8 November 2026
Custom GPT retirement in December 2026: what to do
OpenAI is retiring custom GPTs: they stop running on 11 December 2026, and Enterprise and FedRAMP workspaces with an approved deferral have until 11 February 2027. A GPT's instructions, knowledge files and connected apps can move into a ChatGPT plugin, but custom Actions do not migrate: they must be rebuilt as an MCP server or connector. If your GPT calls an API, start with its Actions.
Key dates
| Date | What happens |
|---|---|
| 11 September 2026 | Retirement announced; migration to ChatGPT plugins available |
| 11 December 2026 | Custom GPTs stop running |
| 11 February 2027 | Cut-off for Enterprise and FedRAMP workspaces with an approved deferral |
What moves and what does not
- Moves into a plugin: instructions, knowledge files, connected apps.
- Does not move: custom Actions (the OpenAPI-schema calls to your API). Rebuild them as a remote MCP server.
- Set again: sharing, model choice and conversation starters.
Checklist by kind of GPT
GPT with instructions and files only
Use OpenAI's migration to a plugin, then test the skills it creates. Nothing else to rebuild.
GPT with an Action and no authentication
Convert the schema (free converter), host the MCP server and add it to ChatGPT with "No authentication". The quickest case.
GPT with an API-key Action
Keep the key on the MCP server. ChatGPT's custom MCP servers authenticate with OAuth or not at all, so a private API needs either an OAuth front door (ActionBridge provides one) or a server that holds the key and is itself protected.
GPT with an OAuth Action
The MCP server runs the OAuth sign-in for each user with your existing OAuth app. Add the server's callback URL to the app's redirect URIs before you switch.
Public GPT in the GPT Store
Your users need the new plugin. Plan an announcement and give them the new link before 11 December, because the GPT stops answering on that date.
How to rebuild an Action
Follow the step-by-step guide: how to migrate custom GPT Actions to MCP. If you would rather not run a server, ActionBridge hosts it from the same schema.
Frequently asked questions
Can I keep my GPT after 11 December 2026?
No. OpenAI says custom GPTs stop running on that date, except Enterprise and FedRAMP workspaces with an approved deferral, which have until 11 February 2027.
Will OpenAI migrate my Actions automatically?
No. OpenAI's FAQ says custom Actions do not carry over and must be rebuilt as an MCP server or connector.
Does an MCP server also work outside ChatGPT?
Yes. The same remote MCP server works in Claude, Claude Code, Cursor, VS Code and other MCP clients, which an Action never could.
Last updated 8 November 2026. Questions or corrections: [email protected].