Display highly visible notification if the last command failed in the Microsoft Terminal using PowerShell

redalert.ps1

# Put this code in your PowerShell profile script
# This requires the MSTerminalSettings module which you can download with:
# Install-Module MSTerminalSettings -Scope CurrentUser -Repository PSGallery

Import-Module MSTerminalSettings
$msTermProfileName = 'pwsh' # Replace with whatever Terminal profile name you're using
$msTermProfile     = Get-MSTerminalProfile -Name $msTermProfileName
$script:bombThrown = $false
function prompt {
    if ($? -eq $false) {
        # RED ALERT!!!
        # Only do this if we're using Microsoft Terminal
        if ((Get-Process -Id $PID).Parent.Parent.ProcessName -eq 'WindowsTerminal') {
            Set-MSTerminalProfile -Name $msTermProfile.name -BackgroundImage 'https://media.giphy.com/media/HhTXt43pk1I1W/giphy.gif' -UseAcrylic:$false
            $script:bombThrown = $true
        }
    } else {
        # Reset to previous settings
        if ($script:bombThrown) {
            Set-MSTerminalProfile -Name $msTermProfile.name -BackgroundImage $msTermProfile.backgroundImage -UseAcrylic:$msTermProfile.useAcrylic
            $script:bombThrown = $false
        }
    }
}

Great idea, this is fun :)

Set-MSTerminalProfile -Name pwsh -CommandLine "pwsh -noexit -command `$env:WT_PROFILE = 'pwsh'"
Set-MSTerminalProfile -Name powershell -CommandLine "powershell -noexit -command `$env:WT_PROFILE = 'powershell'"

function prompt {
  $IsFail = !$?
  if(!$Global:__PromptPS) {
    $Runspace = [runspacefactory]::CreateRunspace()
    $Global:__PromptPS = [PowerShell]::Create()
    $Global:__PromptPS.Runspace = $Runspace
    $Runspace.Open()
    [void]$Global:__PromptPS.Addscript({
      ipmo msterminal
      $OldProfile = Get-MSTerminalProfile -Name $env:WT_PROFILE
      Set-MSTerminalProfile -name $env:WT_PROFILE -BackgroundImage 'https://media.giphy.com/media/ErE2BHnoCWsYU/giphy.gif' -backgroundImageStretchMode uniformToFill -UseAcrylic:$False
      Start-Sleep -Seconds 2.41
      $OldProfile | Set-MSTerminalProfile
    })
  }
  if($IsFail) {
    [void]$Global:__PromptPS.BeginInvoke()
  }
  "PS $($executionContext.SessionState.Path.CurrentLocation)$('>' * ($nestedPromptLevel + 1)) ";
}

# Use this to reset the runspace if you update the function
$global:__PromptPS.Dispose(); $global:__PromptPS = $null

For bonus notification visibility, you could add this function and point it at an appropriate sound when you error.

Function Play-Sound{
Param(
	[Parameter(Mandatory=$True,Position=0)]$SoundFile
	)
    $player = New-Object System.Media.SoundPlayer $SoundFile
    $player.Play();
}

You might consider adding a blowoff valve for robocopy:

The return code from Robocopy is a bitmap, defined as follows:

    Hex   Decimal  Meaning if set

    0×00   0       No errors occurred, and no copying was done.
                   The source and destination directory trees are completely synchronized. 

    0×01   1       One or more files were copied successfully (that is, new files have arrived).

    0×02   2       Some Extra files or directories were detected. No files were copied
                   Examine the output log for details. 

    0×04   4       Some Mismatched files or directories were detected.
                   Examine the output log. Housekeeping might be required.

    0×08   8       Some files or directories could not be copied
                   (copy errors occurred and the retry limit was exceeded).
                   Check these errors further.

    0×10  16       Serious error. Robocopy did not copy any files.
                   Either a usage error or an error due to insufficient access privileges
                   on the source or destination directories.