Keep your agent's memory outside any one assistant, and connect the assistants
you use to it. With JustOnce, you add https://mcp.justonce.ai once in each
assistant and sign in. Every assistant you connect then reads the same memory,
so you can switch assistants, or use several, and what you saved is already
there.
As of 26 October 2026, JustOnce works with Claude, ChatGPT (Business, Enterprise and Edu), Cursor, VS Code, Gemini CLI, Codex and Claude Code. On ChatGPT Pro your assistant can read your memory but not save to it. This guide takes about ten minutes, the Free plan is enough to start, and you can create your JustOnce account as you connect.
What does it mean to give an AI agent a memory?
Your assistant already has some memory of its own, and it's often good. ChatGPT, for example, lets you edit or delete individual saved memories, and OpenAI says that depending on your plan and platform, the controls "can also include search, sorting, automatic prioritization, and version history" (checked 26 October 2026).
The difference is where the memory lives. Built-in memory sits inside one company's app. A memory layer like JustOnce sits outside it, and assistants connect to it over the Model Context Protocol (MCP). Your memory lives in JustOnce, not inside one assistant, so each assistant you connect starts from the same facts. You can see, correct or erase any memory at app.justonce.ai. Corrections keep the old value.
Step 1: Connect your assistant
Every assistant connects to the same address, https://mcp.justonce.ai, and
signs in with OAuth, so there's no API key to paste. No JustOnce account yet?
Sign up in the sign-in window when you connect. Start with the assistant you use
most; you can add the others at any time. The connect page has the
same steps, with one-click buttons where an assistant offers them.
Claude: claude.ai, Claude Desktop and the Claude app
On the web, go to Customize → Connectors → + Add → Add custom connector,
paste https://mcp.justonce.ai, choose Add, and sign in to JustOnce when
the window opens. The connect page's Add to Claude button fills in the name
and address for you; sign in to claude.ai before you press it.
- Any Claude plan works. Anthropic says custom connectors are available "for users on Free, Pro, Max, Team, and Enterprise plans", and "Free users are limited to one custom connector" (checked 26 October 2026). One is all JustOnce needs.
- On Team or Enterprise, an owner adds the connector once in Organization settings → Connectors → Add → Custom → Web.
- One connection covers every Claude app. The connector belongs to your Claude account, so the web, the desktop app and the Claude app on your phone all reach the same memory.
Claude Code
Run this once in a terminal, then run /mcp inside Claude Code and pick
JustOnce to sign in:
claude mcp add --transport http justonce https://mcp.justonce.ai
Or, if Claude Code is signed in with the same Claude account, use the connector you've already added.
ChatGPT: Business, Enterprise and Edu
ChatGPT adds JustOnce on the web, not in its desktop or phone apps:
- Open chatgpt.com/plugins, select +, then Add custom MCP server.
- Give it a name, paste
https://mcp.justonce.aias the Server URL, and choose OAuth. - Sign in to JustOnce, choose Create as a plugin, and install it.
- In a chat, type @ and pick JustOnce.
On Business, an admin or owner adds it for the workspace. On a personal Pro plan, OpenAI gives custom MCP servers "read/fetch permissions" (checked 26 October 2026), so ChatGPT Pro can recall but not save. Free and Go don't offer custom MCP servers, and we haven't confirmed Plus.
ChatGPT sees all your memories and all of JustOnce's tools, like your other assistants. One rule is different: through ChatGPT, JustOnce refuses to save what looks like a password, PIN, card, bank or ID number; add those in the app instead.
Codex CLI
Two commands in a terminal. The second opens your browser to sign in:
codex mcp add justonce --url https://mcp.justonce.ai
codex mcp login justonce
Cursor
The connect page's Add to Cursor button installs JustOnce in one click. Or
add it to ~/.cursor/mcp.json by hand:
{
"mcpServers": {
"justonce": { "url": "https://mcp.justonce.ai" }
}
}
When Cursor shows Needs login next to JustOnce, click it and sign in.
VS Code with GitHub Copilot
Open the Command Palette, run MCP: Add Server, choose HTTP, and paste
https://mcp.justonce.ai. Or use the connect page's Add to VS Code button.
Copilot's agent mode asks you to sign in when it calls a JustOnce tool. On Copilot
Business or Enterprise, your organisation has to allow MCP servers in Copilot.
Gemini CLI
Run this in a terminal, then run /mcp auth justonce inside Gemini CLI to sign
in:
gemini mcp add --transport http justonce https://mcp.justonce.ai
This is the Gemini command-line tool. The Gemini app doesn't connect to JustOnce yet.
Glama
Add a remote MCP server with https://mcp.justonce.ai, and sign in when Glama
sends you to JustOnce. We checked Glama's connection against our live server,
but haven't confirmed its in-app steps.
Step 2: Tell it things once
Start with the things you're tired of repeating. Say them plainly, and ask your assistant to save them to JustOnce:
Remember this in JustOnce: I prefer aisle seats. The car is due for a service in March. I write in Australian English. My manager is Priya and our team meets on Tuesdays.
Your assistant saves them to JustOnce. You don't need a special format. A good rule is one fact per sentence, said the way you'd say it to a person.
Bring in what another assistant already knows. Paste in what an assistant already knows and JustOnce saves it. Ask the other assistant to list what it remembers about you, copy the answer into a connected assistant, and say:
Import these into JustOnce as separate memories.
It can import up to 50 at a time.
What it costs. Saving draws on your monthly allowance; recall and search are always free, on every plan. The Free plan includes 20 memories and 10 pages of documents a month. The pricing page has the rest.
Step 3: Find it in a new chat, or in another assistant
Open a brand-new chat and ask something only the memory would know:
When is the car due for a service?
Your assistant searches JustOnce and answers from what you saved. If it ever answers without looking, ask it to check JustOnce.
Then ask somewhere else:
- In another assistant. Save the fact in Claude, then ask Cursor, Codex or ChatGPT the same question. It's the same memory.
- In Claude Code, ask "What spelling do I write in?" from any project.
- On your phone, open the Claude app, signed in to the same account, and ask about your manager's name.
Switch assistants, or use several
Because the memory stays in one place, changing assistants doesn't mean starting again. Connect the new one, sign in, and what you saved is already there. Use Claude for writing and Cursor for code, or ChatGPT at work and Claude at home: each reads and saves to the same memory.
Disconnecting an assistant doesn't touch what's in JustOnce. The memory is still there for every other assistant you've connected, and in the web app.
Correct it, look back, or erase it
- Correct it. "In JustOnce, correct the car service: it's now due in April." A correction keeps the earlier value, so you can still ask what was true last March. That history covers your own memories.
- Check it. Every memory has its own page in the web app, with its history.
- Erase it. Forget means gone — there's no restore. If you only want something out of the way, archive it in the web app instead.
Corrections and erasing happen as soon as you ask. Sharing and invitations are the ones that wait for your approval (see below).
Which assistants can use JustOnce today?
Checked 26 October 2026 against our live server: for each assistant we signed in with its real sign-in details, got a token, listed the tools and made a read. That checks the connection; it isn't a click-through of every vendor's app.
| Assistant | State |
|---|---|
| Claude (claude.ai, Claude Desktop, the Claude app) | Works |
| Claude Code | Works |
| ChatGPT on Business, Enterprise and Edu (web) | Works |
| ChatGPT Pro | Recall only |
| Codex CLI | Works |
| Cursor | Works |
| VS Code (GitHub Copilot agent mode) | Works |
| Gemini CLI | Works |
| Glama | Works, checked at the connection level; in-app steps unconfirmed |
| Windsurf | Testing |
| Grok Bot | Testing. JustOnce now accepts the sign-in addresses Grok Bot uses, but we haven't finished a live test of a real connection. |
| Meta Muse, OpenAI dots, the Gemini app, consumer Copilot | Not yet |
The states are Works, Recall only, Testing and Not yet. We move an assistant up only after a live check passes, and the agents page keeps the current board. Can I share my AI agent with my partner? explains where Muse, dots and Grok Bot stand.
Frequently asked
Does a new assistant see everything I've saved?
Yes. Every assistant you connect sees the same memories, ChatGPT included. On ChatGPT Pro it can read them but not save new ones.
What happens to my memory if I stop using an assistant?
Nothing. Disconnecting an assistant doesn't touch what's in JustOnce, and you can still see everything at app.justonce.ai. Ask us for a copy of your data any time; one-click export isn't built yet.
Is it private?
It's encrypted at rest with AES-256-GCM — memories under a key for their space, documents under a key for your account. JustOnce holds the keys, so it isn't end-to-end. JustOnce never uses your memories to train AI models, and our AI provider, Anthropic, doesn't train on them either.
Can I share some of it?
Yes, on Plus or Pro. You create a space and invite people by email, and when your assistant asks to share something or invite someone, nothing is shared or sent until you approve it in JustOnce. Approve it in the app — we ask you to confirm it's you. The sharing guide walks through it.
Can my agent keep documents too?
Yes. Your AI reads the file, saves what it says, and keeps the original with it. The document store guide covers file types and limits, and the features page has more on how recall works.
