JustOnce is a remote MCP server at https://mcp.justonce.ai (Streamable HTTP). Any assistant that supports remote MCP connectors can use it. The steps are the same everywhere; only how you add the URL differs per tool:
Add the server — a one-line command (Claude Code, Gemini CLI), a one-click deeplink (Cursor, VS Code, Claude), or paste the URL into a connector field (ChatGPT, Windsurf, Glama, anything else). Use the URL exactly as shown, with nothing added to the end.
Sign in and allow — your browser opens the JustOnce sign-in. Sign in, or create your account right there, then click Allow on the JustOnce screen that names the app. There is no API key to copy or store.
Ask it to recall — "What do you know about me?" or "Remember that…". The Connections page in the app lists the new connection after the app's first call.
No account yet? Create it while you connect
You don't need to visit the website first. The sign-in page your assistant opens says Sign in or create your account to continue to JustOnce MCP Bridge. The bridge is JustOnce's own sign-in for AI apps.
Choose Continue with Google or Continue with Microsoft Account, or enter your email address and use the code we send you.
If that email has no JustOnce account yet, JustOnce creates a free one for you. The next screen says Your free JustOnce account is ready.
Check the app and the email address shown, then click Allow. You're taken back to your assistant, connected.
Clicking Allow on a new account means you agree to the Terms of Service and Privacy Policy. To see your memories in a browser later, sign in at app.justonce.ai with the same method and email address.
The Allow screen
No app gets access until you approve it on a JustOnce page titled Connect app to JustOnce. It shows:
Who is asking — the app's web address (for example claude.ai or chatgpt.com), or an app on this computer. Only continue if you started connecting it yourself.
What it will be able to do — usually: search and read your memories; save, update and delete your memories; read your profile and context; see your memory categories.
Which account — Signed in as [email protected], with Use a different account if that isn't the one you meant.
Allow connects the app. Cancel connects nothing. The screen stays open for 10 minutes and must be used in the same browser window you signed in with; after that, start connecting again from your assistant.
If the sign-in stops
You already have a JustOnce account — that email address signs in another way (for example Google). Use the button to sign in that way. JustOnce never merges accounts on email alone. See "I already have an account with this email".
Confirm your email address first or We need an email address — the sign-in didn't give JustOnce a confirmed email address. Sign in again with Google or an email code.
This app couldn't start a JustOnce sign-in with The app's return address isn't one JustOnce trusts — a hosted assistant we haven't added yet. Tell us which one.
This sign-in link has expired — close the window and start connecting again from your assistant.
Good to know
There's no limit on how many assistants you connect, on any plan.
Every assistant reads and writes the same memory — there's no per-assistant copy to keep in sync. ChatGPT gets a filtered view (see Connect ChatGPT).
Use the same sign-in method and email address in every assistant. A different email address creates a separate, empty account.
Assistants that run on a website can only sign in if JustOnce trusts the address they return to. Claude, ChatGPT, Grok, Cursor, VS Code and Glama are on that list. Apps on your own computer, such as Claude Code and Gemini CLI, return to your own machine and can sign in.
Under the hood: OAuth with PKCE. Your app registers itself automatically (Dynamic Client Registration or a client metadata document), and JustOnce signs you in through Auth0.