Musca has a set of default key bindings. Each binding simply executes a command. All Musca key bindings start with a modifier key (M below), which is bound to Mod4 by default. Mod4 is usually Super_L or the left hand Windows key. This is most convenient as it leaves Ctrl/Alt free for application use.
| Key | Command | Action |
| M+h |
hsplit 1/2 |
split frame in half horizontally to form two frames. |
| M+v |
vsplit 1/2 |
split frame in half vertically to form two frames. |
| M+r |
remove |
remove the current frame and resize others to fill the gap. |
| M+o |
only |
remove all other frames except the current one, resizing it to full screen. |
| M+u |
undo |
revert the last frame layout change. |
| M+d |
dedicate flip |
(toggle) dedicate the current frame to the current app. |
| M+a |
catchall flip |
(toggle) set the current frame as a catch-all, where all new windows will open. |
| M+Left |
focus left |
change focus to the frame on the left. |
| M+Right |
focus right |
change focus to the frame on the right. |
| M+Up |
focus up |
change focus to the frame above. |
| M+Down |
focus down |
change focus to the frame below. |
| M+Ctrl+Left and M+Ctrl+Right |
resize left/right |
resize current frame horizontally. |
| M+Ctrl+Up and M+Ctrl+Down |
resize up/down |
resize current frame vertically. |