Several games at once

Each game instance has its own control pipe, so one test PC runs several games side by side. A clone of an instance takes a few seconds and about 90 MB.

powershell

pwsh -NoProfile -File clone-instance.ps1 -Slot 2       # versions\1.26.51.01-hi2, ~90 MB, seconds
& .\Start-BeDDGame.ps1 -Instance 1.26.51.01-hi2        # starts it without bringing it forward
Connect-BeDD -PipeName BeDD-1.26.51.01-hi2             # the pipeName in that instance's config

Start-BeDDGame.ps1 -Slot 2 (or -Instance <base>-hi2) makes the clone itself when it is missing. Without -Instance it starts the base instance Be.D.D. finds, or its clone for -Slot 2 and up. clone-instance.ps1 takes slots 1 to 32; for a higher slot use New-BeDDClone -Source <base> -Slot 41 from BeDDSetup.psm1. An existing clone is brought up to date when its base instance has changed.

Rules for parallel runs

A clone has its own mods\, logs, worlds and options. A few rules keep parallel runs from tripping over each other:

Give every instance its own lock file, and find your game by its instance folder, never just by the name Minecraft.Windows (or you close someone else's game).
Start games as Minecraft.Windows.exe (Start-BeDDGame.ps1 does): under another file name the game uses your normal Minecraft profile instead of the instance's.
Make test worlds single-player with Set-WorldSinglePlayer <worldDir> (from the harness shim): games on one PC share an online sign-in, and multiplayer worlds opened at the same time fail with "An error has occurred" (code "Blaze").
A run that joins a server online sets $script:ExclusiveSignaling = $true before Start-Game and gets the PC to itself while the other games close.

Starting a game

Start-BeDDGame.ps1 runs versions\<Instance>\Minecraft.Windows.exe directly, so the game never takes the foreground (LeviLauncher is not needed: the exe loads LeviLamina itself). It returns the process. The instance must have the module in mods\BeDD (Install-BeDDMod), and the manager window must start: otherwise it throws.

Parameter
`-Instance <name>`	the instance to start (default: the one Be.D.D. finds)
`-Slot N`	its clone `<base>-hi<N>` instead
`-VersionsDir <dir>`	LeviLauncher's `versions` folder
`-Label <text>`	the game's name in the manager window (default: the project and worktree of the calling script)

The manager window

The first Start-BeDDGame.ps1 of your logon session opens the manager window, and every later run (from any terminal, harness or agent) reuses it. Every game shows up there as a live picture, and nowhere else: its own window stays off screen, with no taskbar button and nothing in Alt+Tab, so no windows pop up and vanish while several runs start and close games. It never takes the focus.

Look at the title bars: only the terminal is active

Each game is labelled with the project (and worktree) of the script that started it, its instance and pid, and whether input is arriving. -Label on Start-BeDDGame.ps1 names it.
Closing the manager window closes every game in it (it asks first). The games also go if the manager is killed, so nothing is left running in the background.
Double-click a game to show only that one. Right-click it to open its latest.log or instance folder, or to close it.
From a script: BeDDManager.ps1 -List lists the games, -Game <pid> -Action close closes one, -Shutdown closes the manager and every game without asking.

It needs PowerShell 7 (pwsh). A game never runs without it: a game that finds no manager window starts one (config managerScript), and a game that no manager links within 90 s, or that loses its manager for good, closes itself (the reason is in its latest.log).