Rewisp isn't in the App Store, so macOS asks once whether you trust it. Here's exactly what you'll see.
Double-click Rewisp.dmg in your Downloads. A window opens with the app and an Applications shortcut. Drag one onto the other.
Drag it across before you open it. Rewisp's background helper is started from wherever the app lives, so a copy running off the disk image stops working as soon as you eject it. Open it there by mistake and Rewisp will offer to move itself — say yes.
Open Rewisp from your Applications folder. macOS will refuse and say it can't check the app for malicious software. That's normal and it only happens once.
Rewisp isn't notarized with Apple yet (that needs a paid developer account). The code is public if you'd like to read it first.
On macOS 15 and newer, right-click → Open no longer works. Apple removed that shortcut, so there's no "Open" button hiding in the menu. Step 3 is the way through.
Open System Settings → Privacy & Security and scroll down to the Security section. You'll see a line about Rewisp being blocked, with an Open Anyway button next to it.
Click it, confirm with Touch ID or your password, and Rewisp opens.
This button only appears after you've tried to open the app once. If it isn't there, go back and double-click Rewisp, then return here.
Rewisp sets itself up the moment it opens — nothing to run. It just needs permission to read text off your screen.
When macOS asks, turn it on for Rewisp Backend. That's Rewisp's background helper, and it's the whole thing working.
Updating from an older Rewisp? Install this version over the old one — your memories are kept. macOS will ask you to switch screen access on again, because it sees an updated app as a different one. Rewisp walks you through that in one click afterwards.
Already clicked past the prompt? System Settings → Privacy & Security → Screen & System Audio Recording → enable Rewisp Backend. Rewisp restarts itself once you do.
Look for the wisp in your menu bar. Press ⌘⇧Space anywhere to ask your memory something.