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WT_SESSION env variable

Category: device · Baseline: rich

$WT_SESSION
The WT_SESSION environment variable is set by Windows Terminal to a GUID that uniquely identifies the current terminal session. A companion variable, WT_PROFILE_ID, identifies the Windows Terminal profile that launched the shell. Applications use WT_SESSION as the canonical way to detect Windows Terminal, since older versions did not set TERM_PROGRAM and the TERM value on Windows is typically inherited from the underlying console host rather than chosen by Windows Terminal itself.
How this is testedmanual
Manual verification required — no automated probe available.

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.

Supported by 0 of 14 backends (0%)

Terminal Applications

TerminalVersionSupportNotes
iTerm23.6.9? unknown
Ghostty1.3.1? unknown
Terminal.app2.15? unknown
Kitty0.46.2? unknown
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? unknown
vt100.js0.2.1? unknown
vterm0.2.0? unknown
WezTerm0.1.0-fork.5? unknown
xterm.js5.5.0? unknown