focus_by_cursor

macOS only: This tool works exclusively on macOS with yabai installed.

Automatically focuses the yabai window under your mouse cursor, without clicks.

Getting Started

Prerequisites

• Homebrew installed (see https://brew.sh).

• yabai (tiling window manager) installed and running:

  brew install koekeishiya/formulae/yabai
  

• Accessibility permissions for yabai:

  • Open System Settings → Privacy & Security → Accessibility.
  • Click +, press Cmd+Shift+G, enter /opt/homebrew/bin/yabai, and click Open.
  • Ensure the checkbox next to yabai is checked.

• Input Monitoring permissions for focus_by_cursor binary:

  • Build and install the binary (see below).
  • Open System Settings → Privacy & Security → Input Monitoring.
  • Click +, press Cmd+Shift+G, enter /usr/local/bin/focus_by_cursor, and click Open.
  • Ensure the checkbox is checked.

Build & Install

• Clone the repository:

  git clone https://github.com/kastastin/focus_by_cursor.git
  cd focus_by_cursor
  

• Build in release mode:

  cargo build --release
  

• Install to your PATH:

  sudo mv target/release/focus_by_cursor /usr/local/bin/focus_by_cursor
  sudo chmod +x /usr/local/bin/focus_by_cursor
  

• Verify installation:

  which focus_by_cursor  # should print /usr/local/bin/focus_by_cursor
  

Usage

• Run the listener:

  focus_by_cursor
  

• The program will listen for mouse moves and focus windows under the cursor.

• Press Ctrl+C to stop.

How It Works

• Listens to global mouse-move events via rdev.
• Debounces events to fire at most once every 50 ms.
• Queries yabai for all windows (yabai -m query --windows).
• Parses JSON output to find which window contains the cursor point.
• Focuses that window via yabai -m window --focus <id>.