Tessa Guide
Everything Tessa does and every key it answers to. If something here is wrong or missing, tell us and it gets fixed.
Installing Tessa
Download the disk image, drag Tessa to your Applications folder, and open it. It lives in the menu bar rather than the Dock: the row of nine marks is the desktop switcher, and the menu behind it has the settings window, the cheat sheet and the licence.
System requirements
- macOS 14 or later, on Apple silicon or Intel.
- No terminal, no configuration file, and no change to System Integrity Protection.
Permissions
Tessa asks for Accessibility the first time it runs. That permission is what lets it read where your windows are and move them; without it, it can see nothing and place nothing. macOS will send you to System Settings to grant it.
It asks once. Every build is signed with the same Developer ID certificate, so updating Tessa does not reset the grant. Nothing else is requested: no screen recording, no input monitoring, no full disk access.
Activating Tessa
The first time you open Tessa it starts a fourteen-day trial. There is no card and no account, and the trial is tied to the Mac rather than to a person.
When it ends, buy a licence and Tessa will ask for the code that arrives by email. One licence covers two machines; if you need a third slot, release one from your account page or from the Mac itself before you sell it.
Once activated, Tessa checks in about once a week. If it cannot reach the server it keeps working — a licence lives thirty days with thirty more of grace, so roughly two months offline before anything asks you for anything.
How windows are placed
A new window halves the focused pane along its longer edge. On a wide display the first split is vertical, the next inside it is horizontal, and so on down. Close a window and its neighbour reclaims the space.
Move the focus with ⌥H ⌥J ⌥K ⌥L, or the arrow keys with the same modifier — both are bound. Hold ⇧ as well to swap the window rather than the focus, and ⌃ to move the shared edge.
Desktops
There are nine, and ⌥1 to ⌥9 switch between them instantly.⌥⇧1 to ⌥⇧9 send the focused window to one without following it.⌥D puts every window on this desktop out of sight so you can see the desktop itself, and puts them back when you press it again.
These are Tessa's own desktops, not macOS Spaces. That is the trade for never touching System Integrity Protection, and it is why Mission Control does not know about them.
The launcher
⌥Space opens it. Type a few letters to go to an application's window, or to start it if it is not running. ⌥⇧↵ brings the window to the desktop you are on instead of going to it.
The cheat sheet
⌥/ shows every binding, including any you have changed. It is the fastest way to remember a key without leaving what you are doing.
Gaps and rules
The Tiling tab has two sliders: the inner gap between neighbouring windows, and the outer gap between the windows and the screen edge.
Underneath are two lists. Floating applications are left where they are and never tiled; Tessa adds one itself if it gives up trying to place an app, and removing the row makes it try again. Ignored applications are treated as though they do not exist, and no space is kept for them.
The focus border
An outline around the focused window, with its own colour, opacity and radius — the default radius matches macOS window corners. Focus can also follow the cursor, with a dwell time before it does, so passing over a window does not steal focus from the one you are typing in.
Changing a shortcut
Open the Shortcuts tab, click the binding you want to change, and press the keys. Escape cancels, × unbinds it and gives the key back to your other applications, and↺ puts Tessa's own back. If a chord is already taken, Tessa says so rather than quietly stealing it.
The primary modifier at the top of that tab is ⌥ by default and can be⌃ instead. Every binding follows it, including the desktop keys.
Troubleshooting
A window will not tile
Some windows are the wrong shape for a pane, and some applications refuse to be moved at all. Check the Floating list in the Tiling tab: if Tessa gave up on an app it will have added it there, and removing the row makes it try again.
A shortcut does nothing
Something else on the machine probably holds that chord. Open the Shortcuts tab and rebind it; Tessa will tell you what already has a key when you try to take it.
Tessa says it cannot reach the server
It keeps working. A failed request is never read as a refusal, and you have about two months of grace before it matters.
Uninstalling
Quit Tessa and drag it to the bin. There is no daemon, no root helper and nothing injected into another application, so your Mac is exactly as it was. Sign the Mac out first from the licence pane if you want the seat back for another machine.