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Notifications (OSC 777)

Category: extensions · Baseline: rich · Tags: Operating System Commands (OSC) · Specification ↗

ESC ] 777 ; notify ; title ; body BEL
OSC 777 is the rxvt-unicode (urxvt) notification extension, providing structured desktop notifications with separate title and body fields. The sequence ESC ] 777 ; notify ; title ; body BEL triggers a system notification. Unlike OSC 9 which sends a single message string, OSC 777 separates the title and body, giving notification managers more control over presentation. Originally from rxvt-unicode, it has been adopted by foot, Ghostty, WezTerm, and other modern terminals as a simple cross-terminal notification mechanism.
How this is testedpartial
Send OSC 777 ; notify ; test ; body BEL and verify the terminal consumes the notification sequence (cursor position unchanged).

The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.

Analysis2026-04-06

Supported by all 3 tested terminals — universal adoption. Part of the Rich TUI baseline.

Supported by 5 of 14 backends (36%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9✓ yes
Ghostty1.3.1✓ yes
Kitty0.46.2✓ yes
VS Code1.113.0? unknown
Warp0.2026.03.18.08.24.03? unknown
Cursor2.6.21? unknown
Terminal.app2.15? unknown

Headless Backends

Parser correctness only — a means the parser accepts the sequence.

BackendVersionSupportNotes
Alacritty0.26.0? unknown
vt100.js0.2.1? unknown
vterm0.2.0? unknown
WezTerm0.1.0-fork.5? unknown
xterm.js5.5.0? unknown