attn .

That's it. A native window opens with your project's markdown rendered beautifully — with live reload, a file tree, tabs, and a built-in editor. No config, no browser, no 200MB runtime.

Why attn?

Most markdown previewers are either browser tabs you have to manually refresh, or Electron apps that eat your RAM for breakfast.

attn is a single <20MB binary. It forks to background as a daemon, opens a native macOS window, and watches your files. Edit in Vim, VS Code, whatever — attn reloads instantly. Open another file? It joins the same window as a tab.

What you get:

• Live reload — save a file, see the change. No refresh button.
• Interactive checkboxes — click a - [ ] task and it writes back to the file.
• Built-in editor — hit Cmd+E to toggle a full ProseMirror editor with syntax highlighting, math, and mermaid diagrams.
• File tree + fuzzy search — browse your project with Cmd+P. Lazy-loads folders so it's fast on huge repos.
• Tabs + projects — open multiple files, switch between projects with Cmd+;. attn remembers your workspaces.
• Mermaid diagrams — flowcharts, sequence diagrams, and more render inline from fenced code blocks.
• Media support — images (with zoom/pan), video, and audio play natively.
• Paper & ink themes — warm parchment light theme by default, cool dark theme with --dark.
• Single instance — run attn from ten terminals. One daemon, one window, new tab each time.

Install

Homebrew

brew install lightsofapollo/attn/attn

npm

npx attnmd
# or
npm install -g attnmd && attn

From source (crates.io)

cargo install attn

From source (git)

git clone https://github.com/lightsofapollo/attn.git
cd attn && cargo install --path .

Requires Rust 1.85+. For npm installs, Node 18+ is required.

Usage

attn                     # open current directory
attn README.md           # open a file
attn ~/projects/myapp    # open a project
attn --dark              # force dark mode
attn --status todo.md    # print task progress: "3/5 tasks complete"
attn --json spec.md      # dump document structure as JSON

Keyboard shortcuts

| Shortcut | Action | |---|---| | Cmd+P | Fuzzy file search | | Cmd+E | Toggle editor | | Cmd+F | Find & replace | | Cmd+; | Switch project | | Cmd+W | Close tab | | Cmd+Tab / Cmd+Shift+Tab | Navigate tabs | | Cmd+= / Cmd+- | Zoom in / out | | Cmd+0 | Reset zoom | | Cmd+/ | Show all shortcuts |

How it works

The Svelte 5 frontend is compiled by Vite and embedded into the Rust binary at build time. No bundled web server, no extracted assets — it's a single self-contained executable.

First launch forks a daemon to the background. The daemon opens a native window via wry (the same webview engine behind Tauri) and listens on a Unix socket. Subsequent attn calls connect to the socket and open new tabs in the existing window. If the binary changes (you rebuild), the old daemon is automatically replaced.

src/
  main.rs       CLI, native window, keyboard shortcuts
  daemon.rs     Unix socket IPC, single-instance daemon
  watcher.rs    File system monitoring with debouncing
  markdown.rs   Structure extraction (tasks, phases, file refs)
  ipc.rs        Webview ↔ Rust messaging
  files.rs      File tree, media type detection
  projects.rs   Project registry

web/src/        Svelte 5 frontend
web/styles/     Tailwind CSS

Contributing

task dev                              # Vite HMR + Rust in foreground
task dev ATTN_PATH=path/to/file.md    # Open a specific file

The task dev command starts Vite for hot module replacement and runs the Rust binary in foreground mode, pointed at the Vite dev server.

scripts/build.sh            # Debug build
scripts/build.sh release    # Release build
scripts/build.sh prod       # Production build

License

MIT