How to add a memory MCP server to ChatGPT

Last updated October 30, 2026

ChatGPT can connect to a remote MCP server that you add yourself, on chatgpt.com in a browser. This needs a paid ChatGPT plan that offers custom MCP servers; in a Business or Enterprise workspace, an admin or owner adds it. To add Memlo, open Plugins, choose the + button, then "Add custom MCP server", enter https://memlo.ai/mcp with OAuth sign-in, and sign in to Memlo. ChatGPT then searches and saves the same memories as Claude Code, Codex and your other agents.

What you need

• A paid ChatGPT plan that offers custom MCP servers. In a Business or Enterprise workspace, an admin or owner adds the server for the workspace.
• ChatGPT on chatgpt.com in a browser, for the setup.
• A Memlo account. Accounts are by invitation for now; you can join the waitlist on the home page.

Add the server

These are the steps on Memlo's setup page, which match OpenAI's own instructions for adding a custom MCP server. OpenAI notes that account and workspace policies apply to adding and using one.

1. Open Plugins on chatgpt.com, choose the + button, then "Add custom MCP server".
2. Name: Memlo. Server URL: https://memlo.ai/mcp.
3. Authentication: OAuth. Leave the client ID and secret empty: ChatGPT registers itself.
4. Read the warning, choose "I understand and want to continue", then "Create as a plugin".
5. Choose Connect, and sign in to Memlo in the page that opens.
6. The consent page asks "Allow ChatGPT (chatgpt.com) to use Memlo?". Choose Continue.

The URL must end in /mcp. A server saved as https://memlo.ai without it never finishes connecting: remove it and add it again.

Use it in a chat

In a chat, type @ and choose Memlo to use it in that conversation. Then ask in plain words:

• "Use Memlo to tell me who I'm signed in as." ChatGPT calls whoami.
• "Search Memlo for how Acme Pay webhooks retry." ChatGPT calls search_memories and reads the best match.
• "Save to Memlo: the billing service moved to the ledger-api." ChatGPT saves a memory.

ChatGPT may ask you to confirm before a tool changes or deletes memories.

Why use an outside memory in ChatGPT

ChatGPT has its own memory, and it stays inside ChatGPT. A memory server you add yourself is shared with your other agents: a decision saved from ChatGPT is found by Claude Code or Codex the next day, and the other way around. With Memlo you can also:

• read, edit and roll back each memory in the Memlo app, with every version kept;
• see which person, and which connected app, wrote each version, with memory_history;
• share a space or a page with people by email as a Viewer or an Editor.

What a custom MCP server can do in ChatGPT

A custom MCP server can read and change data in another service. That's why ChatGPT shows a warning when you add one, and why it may ask before a tool changes something. Add only servers you trust. You can disconnect ChatGPT from Memlo at any time: in Memlo, open Account settings and choose Disconnect next to ChatGPT under Connected apps. To remove the server from ChatGPT, remove the plugin under Plugins.

Frequently asked questions

Can ChatGPT use MCP servers?

Yes. On a paid plan that offers custom MCP servers, you can add a remote MCP server on chatgpt.com. In a Business or Enterprise workspace, an admin or owner adds it.

Does a ChatGPT MCP server need an API key?

Not for Memlo. Choose OAuth when you add it and leave the client ID and secret empty. You sign in with your own Memlo account.

Which transport does ChatGPT use?

Streamable HTTP, at the server's /mcp address. Memlo has no separate SSE address.

Can ChatGPT and Claude Code share memories?

Yes. Connect both to https://memlo.ai/mcp and sign in to the same Memlo account. A memory saved from one is found from the other.

Sources

Checked on October 30, 2026:

• Connect and test your plugin, OpenAI developer docs, section "Add the MCP server"
• Memlo: the setup page, section "Set up ChatGPT"