Window Rules

Window rules live in rules.toml (path is set via [rules] in wm.toml). They are reloaded by Super+R together with wm.toml. A missing file means no rules.

Matching

Rules are evaluated on manage_start and on app_id / title changes. First match wins. At least one matcher (app_id, class, or title) is required — rules with none are dropped with a warning.

[[window]]
app_id     = "dota2"
layout     = "game-mode"
anchor     = "center"     # center | top | bottom | left | right
size       = "native"     # "native" | "WxH" | "FxF"
scale      = 1.0
tag        = 9
fullscreen = false

Sizing another app

[[window]]
class  = "steam_app_570"
layout = "game-mode"
size   = "1920x1080"

Per-window opacity

opacity is a 0.0..1.0 fraction; omit it to inherit the global [opacity] default from wm.toml.

[[window]]
app_id  = "com.mitchellh.ghostty"
opacity = 0.85

[[window]]
app_id  = "mpv"
opacity = 1.0    # force fully opaque

Game-mode engine

Options for the game-mode layout. They only apply when at least one rule targets layout = "game-mode".

[game_mode]
remainder_layout = "rows"   # tile | grid | monocle | scrolling | float | rows
gaps_inner       = 8
fallback_layout  = "grid"   # used when no anchor window is present on the output