vm-lab

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Parallels macOS VM lab: GUI automation, Peekaboo, TCC, Ghostty.

steipete By steipete schedule Updated 5/23/2026

name: vm-lab description: "Parallels macOS VM lab: GUI automation, Peekaboo, TCC, Ghostty."

VM Lab

Use this when the task needs a clean macOS VM to test GUI automation, TCC prompts, screenshot capture, clicking, typing, performance, or "two-way validation" of Peekaboo-like tools.

Core idea: run the tool under test inside the guest, but verify it from outside the guest with Parallels screenshots and host-side observations. Do not close apps you do not own.

Safety Rules

  • Treat the VM snapshot as disposable, not the host.
  • Never print secrets. If op is needed, follow the 1Password skill and run it only inside tmux.
  • Prefer fresh app windows you create yourself: TextEdit, a local HTML test page, or a small test app.
  • Avoid modifying host state except temporary screenshots under /tmp.
  • For git repos inside the VM, use HTTPS remotes and normal branch discipline.

VM Discovery

List VMs:

prlctl list --all

Get VM status/IP:

prlctl list --info "macOS Tahoe"

Run guest commands as Peter:

prlctl exec "macOS Tahoe" \
  'sudo -u steipete -H /bin/zsh -lc '\''source ~/.zprofile 2>/dev/null || true; uname -a'\'''

Capture an independent host-side screenshot:

prlctl capture "macOS Tahoe" --file /tmp/vm-reference.png
sips -g pixelWidth -g pixelHeight /tmp/vm-reference.png

TCC / GUI Attribution

For macOS Screen Recording and Accessibility, the responsible process matters.

  • prlctl exec is headless and can fail to produce useful Screen Recording attribution.
  • Launch the test command from a visible terminal app in the guest when Screen Recording is involved.
  • Ghostty works as a GUI terminal if installed.
  • After a first failed capture, check System Settings > Privacy & Security > Screen & System Audio Recording.
  • permissions status run through prlctl exec may still report Screen Recording false after Ghostty is allowed; validate Screen Recording by rerunning the capture from Ghostty.

Open the Screen Recording pane:

prlctl exec "macOS Tahoe" \
  'sudo -u steipete -H open "x-apple.systempreferences:com.apple.preference.security?Privacy_ScreenCapture"'

Open Ghostty:

prlctl exec "macOS Tahoe" 'sudo -u steipete -H open -a Ghostty'

Running Commands Through Ghostty

Best path: create a guest script with prlctl exec, open/focus Ghostty, then type only a short launcher path into the visible terminal.

Guest script pattern:

prlctl exec "macOS Tahoe" 'sudo -u steipete -H /bin/zsh -lc '\''cat > /tmp/run-vm-lab.zsh <<EOF
#!/bin/zsh
source ~/.zprofile 2>/dev/null || true
cd ~/Projects/Peekaboo || exit 1
Apps/CLI/.build/debug/peekaboo image --path /tmp/peekaboo-vm.png --json
rc=$?
echo "EXIT:$rc"
[ -f /tmp/peekaboo-vm.png ] && sips -g pixelWidth -g pixelHeight /tmp/peekaboo-vm.png
echo "Press return to close..."
read _
exit $rc
EOF
chmod +x /tmp/run-vm-lab.zsh
ln -sf /tmp/run-vm-lab.zsh /tmp/r
open -a Ghostty'\'''

Then link the launcher into Ghostty's home directory and type ./r with scripts/parallels_type.py. This avoids unreliable path characters in Parallels key injection.

prlctl exec "macOS Tahoe" \
  "sudo -u steipete -H /bin/zsh -lc 'ln -sf /tmp/run-vm-lab.zsh ~/r'"
python3 skills/vm-lab/scripts/parallels_type.py "macOS Tahoe" $'./r\n'

Avoid long command typing. Parallels key injection uses its own key-code table and can be layout-sensitive.

Known Pitfalls

  • macOS clipboard APIs may fail from prlctl exec; pbcopy, AppleScript clipboard, and Peekaboo paste can all fail in headless guest context.
  • open -na Ghostty.app --args -e ... may only focus an existing Ghostty window on macOS; do not assume it runs the command.
  • prlctl exec may re-join argv through a guest shell; for complex payloads, pass one fully shell-quoted command string or create the file with a tiny Python writer.
  • Parallels send-key-event --key uses Parallels key values, not macOS virtual key codes.
  • For normal typing, send prlctl send-key-event <vm> --key <key> with no --event; explicit press/release can repeat or stick. Return is an exception: use press then release.
  • Prefer one prlctl send-key-event --json batch over many separate send-key-event processes; separate calls can drift under focus/latency.
  • Use PRL_KEY_ENTER = 36, PRL_KEY_SLASH = 61, PRL_KEY_R = 27, PRL_KEY_T = 28, PRL_KEY_M = 58, PRL_KEY_P = 33.
  • If keystrokes produce garbage, send Return to clear the line, create a shorter launcher, then retry.
  • If Peekaboo permission probes hang with Screen Recording missing and emit SWIFT TASK CONTINUATION MISUSE, record it as a product bug; do not confuse it with the VM harness.

Two-Way Validation

For each GUI action, verify through two independent signals:

  • Tool-under-test output: JSON, screenshot file, AX result, or app state.
  • External verifier: prlctl capture, host-side image inspection, file content in guest, or process/window state.

Examples:

  • Screenshot: compare Peekaboo image dimensions/content against prlctl capture.
  • Click: use Peekaboo to click a test button, then verify both guest app state and host screenshot.
  • Type: use Peekaboo to type into a controlled text field, then verify AX value and host screenshot.
  • Performance: wrap commands with /usr/bin/time -p; repeat cold/warm runs; keep outputs in /tmp.

Peekaboo VM Baseline

Inside guest:

cd ~/Projects/Peekaboo
git pull --recurse-submodules
swift build --package-path Apps/CLI
Apps/CLI/.build/debug/peekaboo --version
Apps/CLI/.build/debug/peekaboo permissions status --json

Host-side reference capture:

prlctl capture "macOS Tahoe" --file /tmp/vm-prlctl-reference.png

Guest-side Peekaboo capture through Ghostty:

/tmp/r

Compare:

prlctl exec "macOS Tahoe" \
  'sudo -u steipete -H /bin/zsh -lc '\''sips -g pixelWidth -g pixelHeight /tmp/peekaboo-vm.png'\'''
sips -g pixelWidth -g pixelHeight /tmp/vm-prlctl-reference.png

Reporting

When handing off, include only:

  • VM name and OS build.
  • repo commit tested.
  • permission state.
  • commands that passed/failed.
  • independent verifier result.
  • product bugs discovered.
Install via CLI
npx skills add https://github.com/steipete/agent-scripts --skill vm-lab
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