Feature Request: Add terminal session recording to Start-Transcript (capture TUI applications, export to video) #28353

Summary

Start-Transcript should gain the ability to record the terminal session itself — including full-screen interactive TUI applications — and save it in a replayable, time-stamped format (asciicast v3) optionally rendered as a video file (GIF/WebM/MP4). This is the PowerShell-level equivalent of RHEL's system-wide session recording via tlog/SSSD/PAM, or of asciinema/script(1) — notably, the asciinema CLI itself does not support Windows.

Background

Start-Transcript is documented to capture "all command that the user types and all output that appears on the console", but in practice it only captures what flows through the PowerShell host. TUI applications bypass the pipeline entirely:

• On Windows, sconfig (Windows Server) opens the console directly (CONIN$/CONOUT$), switches to raw mode, and paints the screen with VT sequences
• On Linux, nmtui (RHEL), vim, htop, etc. open /dev/tty and use the alternate screen buffer

So a transcript of a session that uses a TUI application is effectively blank for the duration of that application. This was discussed in detail in discussion #28296, where rhubarb-geek-nz confirmed the current behavior is best-effort and noted his console-logger tool proves the technical approach on Windows: a pseudo-console (ConPTY) wrapper can both display and capture interactive programs.

Proposed behavior

Start-Transcript -Path .\audit\session01 -RecordTerminal -RecordingFormat WebM
sconfig        # full-screen TUI — fully recorded
# ... interact ...
Stop-Transcript

Produces:

• session01.txt — the existing text transcript (unchanged)
• session01.cast — time-stamped terminal stream (asciicast v3); always written as source of truth; plays with asciinema play
• session01.webm — rendered video (GIF built-in; WebM/MP4 via ffmpeg when available)

New parameters (strictly additive, existing behavior untouched): -RecordTerminal, -RecordingFormat (Asciicast|Gif|WebM|Mp4), -RecordInput (keystroke capture, off by default due to secret-capture risk), -RecordIdleTimeLimit.

Technical approach: host-level capture — the console host attaches native child processes to a ConPTY (Windows) / PTY (Unix) pair, proxies the VT stream to the real terminal, and tees it with timestamps into the recorder. Only the host can do this transparently; a PSGallery module cannot intercept CONIN$/CONOUT$//dev/tty traffic of arbitrary children.

Scenarios

• Audit/compliance: defensible records of privileged interactive administration (sconfig, nmtui, vendor consoles), aligned with the tlog/SSSD precedent and extendable via Group Policy per RFC0041
• Support/incident response: reproduce exactly what was on screen when a failure occurred inside a TUI app
• Training/docs/bug reports: shareable GIF/WebM of a full session including TUI interactions

Status

• An RFC draft has been submitted per the PowerShell RFC process: RFC: Terminal Session Recording in Start-Transcript PowerShell-RFC#421
• Discussion: What should the transcript ideally capture when a TUI application starts in PowerShell? #28296

Per the RFC process, this issue requests the appropriate Working Group (WG-Interactive) to review whether the RFC can proceed toward an experimental implementation.

/cc rhubarb-geek-nz