Cooper — the open-source Copper app for Windows, macOS & Linux

Cooper is a free, open-source recreation of Copper — the Mac capture app by shadcn — for people who want the same workflow on Windows and Linux, not just macOS. If you searched for a Copper app for Windows, a Copper alternative, or an open-source Copper, this is it.

Cooper is an independent community project. It is not affiliated with or endorsed by shadcn — if you're on a Mac, go buy the original; it's great.

Copper's pitch, which Cooper replicates faithfully: the more you use AI, the more you collect little things you don't want to lose — an answer worth keeping, a link, an idea, three follow-up prompts while the current one is still generating. Cooper combines the useful parts of a to-do list, a clipboard, and a scratchpad, purpose-built for AI-assisted work. It sits next to where you work, is always one shortcut away, and works with all your AI apps, terminals, and browsers — ChatGPT, Claude, Cursor, anything.

Local and private. No sync, no telemetry, no account. Everything lives in a single SQLite file on your machine.

Download

Grab the latest build from Releases — no compiling needed:

OS	File to download
Windows	Cooper_x.y.z_x64-setup.exe (installer) or Cooper_x.y.z_x64_en-US.msi
macOS (Intel & Apple Silicon)	Cooper_x.y.z_universal.dmg
Linux	Cooper_x.y.z_amd64.AppImage (portable — chmod +x and run), or .deb / .rpm

First-run notes:

• Windows: SmartScreen may warn because the binary is unsigned — click More info → Run anyway.
• macOS: unsigned app; right-click → Open the first time (or xattr -dr com.apple.quarantine /Applications/Cooper.app). Grant Accessibility permission for the double-shift capture.
• Linux: the AppImage needs no install. On Wayland use the fallback hotkeys (see below).

How it works

• Select text anywhere → double-tap Left Shift → captured.
• Think of a follow-up prompt → double-tap Right Shift → Cooper appears, type it, keep working.
• Send items back into your AI apps and check them off as you go.

Shortcuts

Action	Shortcut
Capture selected text (any app)	Left Shift + Left Shift
Show / hide Cooper (any app)	Right Shift + Right Shift
Show / hide (fallback)	Ctrl/Cmd + Shift + Space
Capture (fallback)	Ctrl/Cmd + Shift + C
Switch / create section	Ctrl/Cmd + K
Copy selected · Copy as list	Ctrl/Cmd + C · Ctrl/Cmd + Shift + C
Mark as done / Edit / Delete	Space / Enter / Del
Shortcut sheet	Ctrl/Cmd + /

Features

• Capture panel — frameless, always-on-top, docked to the edge of your screen, summoned and dismissed entirely from the keyboard.
• Sections — type # Name to create one; everything you capture lands in the active section until you switch (Ctrl/Cmd+K). Right-click a header to rename, delete, or retarget captures.
• Inline formatting — cards render **bold**, *italic*, ~~strikethrough~~, and `code`. (Underscore emphasis is intentionally unsupported so captured snake_case and __dunder__ code isn't mangled.)
• Copy as List — multi-select items and copy them back out as a Markdown list, ready to paste into a prompt.
• Themes — System / Light / Dark / Glass. Glass is a translucent liquid-glass look built on each OS's cheapest compositor effect: Windows DWM acrylic, macOS NSVisualEffectView vibrancy (GPU-composited, effectively free). Linux gets plain translucency; KWin or picom can blur it.
• Tray app — closes to the tray, optional start-at-login, single-instance.
• Your data stays yours — one SQLite file, plus one-click Export to Markdown so nothing is ever locked in.

Building from source

Prerequisites: Rust, Node 18+, and the Tauri 2 platform prerequisites (WebView2 on Windows — preinstalled on Win 11; libwebkit2gtk-4.1 etc. on Linux).

npm install
npm run tauri dev      # run in development
npm run tauri build    # produce installers/bundles for your OS

One Tauri 2 codebase (Rust core + web UI in the OS webview) compiles to a ~10 MB native binary on every platform. No Electron.

Platform notes

• macOS — the double-shift capture uses a low-level event tap, which requires the Accessibility permission. Without it, the fallback hotkeys still work.
• Linux — the raw keyboard hook works on X11; on Wayland use the fallback hotkeys.
• Capture mechanics — capturing simulates the platform copy chord and reads the clipboard. If nothing was selected, your previous clipboard is restored untouched.

Data

• Database: cooper.db in the app data directory (%APPDATA%/app.cooper.desktop on Windows, ~/Library/Application Support/app.cooper.desktop on macOS, ~/.local/share/app.cooper.desktop on Linux).
• ⋯ → Export to Markdown writes a checklist-style cooper-export.md to your Documents folder.

License

Apache-2.0 — fork it, ship it, build on it.