Window rules#

Rules match windows and apply effects. Each window-rule { } node needs at least one match; matchers are regexes in KDL raw strings.

window-rule {
    match title=#"^Minecraft"# is-xwayland=#false
    exclude title=#"launcher"#
    open-on-workspace 6
    opacity 0.98
    allow-tearing #true
}

window-rule {
    match app-id=#"^foot$"# title=#"^scratch"#
    open-floating #true
    default-size 800 600
    open-centered
    animation "slide" dir="top"
}

Matching#

Selectors AND together within a match node and OR across multiple match nodes, and any matching exclude node vetoes the rule:

Selector	Matches
`app-id`	regex against the app id (X11 class for XWayland windows)
`title`	regex against the window title
`is-xwayland`	X11 windows (`#true`) or native Wayland (`#false`)
`is-floating`	current floating state
`is-fullscreen`	current fullscreen state

Regexes use the lightweight regex-lite dialect and are validated when the config parses; a bad pattern is a config error. Rules apply in file order: scalar effects (workspace, size, opacity) let the later match win, boolean effects accumulate.

The classic no-capture use is keeping your Discord DMs off stream:

window-rule {
    match app-id=#"^discord$"#
    no-capture
}

On your screen the window is normal; every screenshot, recording, and cast sees an opaque black box in its place (rounded to match), and even the close-animation replay stays blacked out. Pixels never leave the compositor.

Effects#

All thirteen effects work today. The open-* family positions the window once, when it maps, and stays as mapped; every other effect is re-resolved on running windows by burrow reload, so a rule edit lands on the apps you already have open. no-anim and animation cover both the open and the close.

Effect	Type	Does
`open-floating`	bool	start floating (or `#false` to force tiling)
`open-on-workspace`	number	map on that workspace (1-based; creates it if needed)
`default-size`	two ints	initial floating size
`open-centered`	flag	center a floating window
`opacity`	0..1	per-window opacity
`allow-tearing`	bool	let this window tear when fullscreen, same as the surface requesting it
`no-anim`	flag	skip this window's open and close animations
`animation`	style	override the open/close style, same grammar as animation styles
`rounding`	px 0..200	override the decoration corner radius for this window
`shadow`	bool	opt this window out of (or back into) the drop shadow
`dim`	bool	opt this window out of (or back into) dim-inactive
`blur`	bool	give this window the blurred backdrop; blur is opt-in per window
`no-capture`	flag	black the window out of every capture path: screenshots, recordings, and casts

Layer rules#

Layer rules target layer surfaces (bars, launchers, wallpaper tools) by namespace, and their effect today is the blurred backdrop:

layer-rule {
    match namespace=#"^quickshell:bar"#
    blur
    ignore-alpha 0.2
}

match namespace is a regex, same dialect as window rules, and multiple match nodes OR together. Three effects:

blur hands the surface the cached backdrop blur (it needs decoration { blur { } } switched on). ignore-alpha masks the blur to the pixels where the surface's own alpha is at or above the threshold (0..1), so a pill-shaped bar blurs only under its pills; unset blurs the whole rect. The mask needs an ARGB buffer, since XRGB surfaces pin alpha to one.
no-anim skips the surface's open and close animations. Shells that remap their layer surfaces on every state change flicker through the popin otherwise; this rule keeps them still.