There’s no AI in Cue. There’s a door.
Cue will never write your notes for you, suggest a to-do or summarize your week. The app stays what it is: a page a day, and the keyboard. But you already talk to an assistant, and it’s a shame it can’t see what you wrote this morning or add the thing you just agreed to.
So Cue speaks MCP, the protocol assistants use to reach tools. Connect one and it works on your days the way another device would: an edit it makes goes through the same sync everything else does, and shows up on your Mac and your iPhone about a second later, in the right place in the right day. It’s free, like the rest of Cue.
Connecting one
- Turn on sync in Cue’s Settings, on the Mac or the iPhone. An assistant works with your account rather than your computer, so this is the one part that needs one.
- Add a custom connector in Claude, ChatGPT or whatever you use, with the URL https://www.usecue.today/mcp. Keep the www.
- Sign in and press Allow. The assistant sends you to Cue’s own consent page, which signs you in with a six-digit code by email and asks whether to connect. That’s it.
Disconnect any assistant, any time, at usecue.today/oauth/consent. The same page lists everything you’ve connected.
What it can do
| Tool | What it does |
|---|---|
| get_day | One day’s page, in order, nested, as Markdown |
| find_todos | To-dos across up to a year of days: the open ones, unless it asks for more |
| search | Lines containing every word, newest days first |
| add_lines | Adds Markdown lines at the end of a day, or after a particular line |
| update_lines | Checks off or reopens, changes a line’s type, rewrites its text, or moves lines (with whatever’s nested under them) to another day |
Nothing deletes. There is no tool for it, and the database refuses it as well: a token an assistant holds can’t delete a line or your account even if it asks Supabase directly, can’t set a password on your account, and can’t change its email address on its own. The worst it can do is add something you didn’t want, which you can delete like any other line — ⇧⌘⌫ on the Mac, a long swipe on the iPhone. (⌘Z won’t: undo reverses your own last action, not another device’s.)
And yes, I checked the row-level security. Every read and write runs as you, under Postgres RLS, and the database checks the token’s signature itself on every single query — so a forged one reads nothing at all. There are tests that try to read another account’s notes, delete what an assistant shouldn’t, and sneak past the rules with a password; they all fail, which is the point. Cue would rather not be the Supabase app you read about on Hacker News.
Things worth knowing
What your assistant does with your days afterwards is its business, covered by its own privacy policy. Cue’s half of the story is in the privacy policy: it still sends nothing to an AI model, and still has no tracking.
Dates are your calendar’s dates, and the server can’t know your time zone, so it asks the assistant to work out what “today” means for you. If you’re typing in a line at the same moment an assistant checks it off, your edit wins and the check-off is lost: sync settles whole lines, not fields.
The whole thing is one Supabase Edge Function acting as another sync client — no extra server, no new table, no service key. How it works, down to the OAuth, is in docs/MCP.md.
Get Cue first