Drop
It lives in the menu bar
Control and backtick. It drops down over whatever you're doing, and gets out of the way just as fast.
An assistant that knows your whole life
Rin gives your Mac a second brain and drops it down from the menu bar whenever you need it. You answer three questions on first run, and from then on it just knows your stuff: your deadlines, your projects, your week.
Download for Mac
Source Free
Open source MIT licensed
Private stays on your disk
macOS 14+ plus a Claude Code plan
How Rin works
Ask
It already knows your week
Nothing to explain, no notes to paste in. It's read the folder before you even open the panel, so the first thing you type can be a real question.
Read
One dot says who needs you
A pale dot pulsing wants an answer, a grey one breathing is still working, amber has ended. A hollow ring hasn't started yet. You read the whole panel in half a second.
Keep
Quit. It's all still there
Close the app, restart the Mac, come back in a week. Every tab reopens right where you left it.
The illustration alongside shows a Mac desktop, where the menu bar glyph 凛 wears a small text face and a faint Tokyo Tower skyline sits in the wallpaper. Rin's panel drops down out of the menu bar carrying three session tabs named vault, essay and rin on a pale tab bar, with a pin and a new-tab button at its end. The question "what is due thursday" is typed, and the answer comes back: bio lab writeup and the history reading response, with the writeup named as the one that eats the evening. Each tab carries a status dot, and the working one carries the engine's asterisk spinner. Below the answer sits the framed prompt line. The app then quits and reopens with the same conversation still on screen.
What you get
The brain ships built
The folders and the daily rhythm arrive ready and empty. Nothing to name, nothing to design. You just talk and it files things where they go.
brain/
├── inbox anything you say in passing
├── projects the things with an end
├── areas school, work, the ongoing stuff
├── resources things you did not write
├── daily one note a day, written for you
└── archive done, and out of the way
Rin has nowhere to send it
No server, no account, no sync. The brain is a folder on your disk you can open with any text editor. A module you add can change that, which is why every module's card says whether it reaches the network.
The rest of it
Small things that make it worth keeping open
Tabs that outlive the app
Every session is on disk as it goes, and a tab still working won't let you close it on a stray click.
One brain, many windows
Every tab reads the same notes. Ask in one, and the next one already knows.
Starts blind, on purpose
It sees your notes and nothing else until you say "connect my calendar". One thing at a time, explained first.
Readable line by line
MIT licensed and small enough to actually read before you trust it with your week.
Never covers your work
It hangs off the menu bar over the top of anything, then leaves without moving a window.
Two keys, always
The same shortcut from any app, any desktop, any full screen video.
Control`
Before you ask
Questions you probably have
Is this just a wrapper around Claude Code?
Partly, and it says so on the tin. Claude Code is the engine. What Rin adds is the panel falling out of the menu bar, tabs that survive quitting, and a brain that already exists on first launch instead of an empty folder you have to figure out yourself.
Where do my notes actually live?
In a plain folder of markdown files on your disk, wherever you put it. Open it in Finder. Edit it in any text editor. Put it in iCloud or under git if you like. Nothing about it is locked to this app.
Does it work with Obsidian?
Yes. The brain is markdown with wikilinks between the notes, which is exactly what Obsidian reads. Point a vault at the same folder and both see the same files.
Can I point it at a folder I already have?
Yes. If you already keep notes somewhere, give it that folder instead and it works with what's there. The starter structure is a convenience, not a requirement.
What does it cost?
Rin is free and MIT licensed, and it always will be. Claude Code isn't, so you need a plan that covers it. That's the only bill involved, and Rin doesn't see a cent of it.
What can it see on my Mac?
Your brain folder, plus Claude's own session files in ~/.claude,
which is how tabs come back labelled after a quit. That's it. It starts with
no access to your calendar, mail or anything else until you ask, one
connection at a time, and Rin has no server to send any of it to. Modules
are the one exception worth knowing: one you add can ship scripts or talk
to a service of its own, and the modules page
says which do.
Before you download
Bring a plan that covers Claude Code
Rin is the window, Claude Code is what runs in it. Every tab is a real session spending real usage, so bring a subscription that covers it. On pay as you go, a few open tabs will drain your balance fast.
About that first launch warning
Rin isn't signed with a paid certificate (that costs about a hundred bucks a year and this app is free, so, no), which means the first launch gets blocked and you have to wave it through by hand. Once, and never again.
Double click Rin and let the warning appear. Press Done, not Move to Trash. Then open System Settings, go to Privacy & Security, and scroll to the bottom: there's a line saying Rin was blocked, with an Open Anyway button beside it. Click it and confirm with your password or Touch ID. Rin opens, and every launch after this one is an ordinary double click.
On a Mac older than macOS 15 there is a shortcut: right click the app, choose Open, then Open again. Apple retired that route in Sequoia.
A signature tells you who wrote an app, not what it does. The source tells you what it does.