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OSC 633;B prompt end

Category: extensions · Baseline: rich · Tags: Operating System Commands (OSC), VS Code Extensions · Specification ↗

ESC ] 633 ; B BEL

OSC 633;B marks the end of the shell prompt and the start of the user's command line, mirroring OSC 133;B. VS Code uses this to identify where the prompt ends and the editable command region begins.

This is essential for VS Code's command decoration system: it lets the terminal draw decorations alongside the prompt without overlapping the user's input area, and lets it correctly identify which characters in scrollback are prompt vs command.

How this is testedpartial
Send OSC 633 ; B BEL and verify the terminal consumes the sequence (cursor doesn't advance, terminal remains responsive).

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 9 tested terminals — universal adoption. Part of the Rich TUI baseline.

Supported by 11 of 14 backends (79%)

Terminal Applications

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

Headless Backends

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

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