Use host_bash for every command in this skill. On Windows, host_bash runs Windows PowerShell with no profile and no interactive prompt. Use PowerShell syntax and Windows paths.

Prefer automation methods in this order:

1. A documented CLI or URI scheme
2. A documented PowerShell module or COM API
3. Microsoft UI Automation
4. Keyboard input only when the target and focus are verified

Avoid screen coordinates and blind keystrokes. They are fragile and can affect the wrong app. Use computer control only when PowerShell and UI Automation cannot complete the task or the user explicitly requests it.

Discover and launch apps

# Find Start menu apps
Get-StartApps | Where-Object Name -Like "*Calculator*"

# Inspect running desktop apps
Get-Process | Where-Object MainWindowTitle | Select-Object Id, ProcessName, MainWindowTitle

# Launch an app or a Windows Settings page
Start-Process calc.exe
Start-Process "ms-settings:privacy-microphone"

# Open a folder in File Explorer
Start-Process explorer.exe -ArgumentList "C:\Users\Public\Documents"

Prefer a stable executable, AppUserModelId, URI scheme, process ID, or automation ID over a localized window title.

Use documented app automation

Microsoft Office desktop apps expose COM APIs. Check that the app is installed before relying on one. Keep the COM object alive for the full operation and release it when finished.

# Create an isolated temporary workbook
$excel = $null
$workbook = $null
$worksheet = $null
$cell = $null
try {
  $excel = New-Object -ComObject Excel.Application
  $excel.Visible = $true
  $workbook = $excel.Workbooks.Add()
  if (-not [string]::IsNullOrEmpty($workbook.Path) -or $workbook.AutoSaveOn) {
    throw "The workbook is not an isolated temporary document."
  }
  $worksheet = $workbook.Worksheets.Item(1)
  $cell = $worksheet.Cells.Item(1, 1)
  $cell.Value2 = "Example"
} finally {
  if ($null -ne $workbook) {
    $workbook.Close($false)
  }
  if ($null -ne $excel) {
    $excel.Quit()
  }
  foreach ($comObject in @($cell, $worksheet, $workbook, $excel)) {
    if ($null -ne $comObject) {
      [System.Runtime.InteropServices.Marshal]::ReleaseComObject($comObject) | Out-Null
    }
  }
}

Close unsaved temporary documents with Close($false), quit the application, and release COM objects in a finally block so cleanup never waits for a save prompt.

Consequential actions are unsupported

Do not use this skill to save, send, delete, or overwrite content. The Windows host executor does not provide an in-process confirmation gate that works for both local and remote assistants.

Treat every existing document, workbook, message, note, calendar item, file, and cloud-backed resource as read-only. AutoSave can persist an edit without an explicit save command. Only edit an isolated temporary document that the automation created during the current task, has no storage path or cloud connection, and has AutoSave definitively disabled. If those conditions cannot be verified, do not edit it.

If the user requests a consequential action, use a dedicated skill or product workflow with its own hard confirmation gate. If none is available, explain the limitation and ask the user to perform that final action manually.

Inspect native UI

Load the built-in UI Automation assemblies and identify elements by process ID, automation ID, control type, or name.

Add-Type -AssemblyName UIAutomationClient

$desktop = [System.Windows.Automation.AutomationElement]::RootElement
$windows = $desktop.FindAll(
  [System.Windows.Automation.TreeScope]::Children,
  [System.Windows.Automation.Condition]::TrueCondition
)

$windows | ForEach-Object {
  [pscustomobject]@{
    Name = $_.Current.Name
    ProcessId = $_.Current.ProcessId
    AutomationId = $_.Current.AutomationId
    ControlType = $_.Current.ControlType.ProgrammaticName
  }
}

Once the target window is known, search its descendants with a PropertyCondition and use the supported pattern, such as InvokePattern, ValuePattern, SelectionItemPattern, or TogglePattern. Check TryGetCurrentPattern before invoking a pattern.

Focus and keyboard fallback

If an app exposes no useful automation pattern, verify the process and window before sending keys:

$process = Get-Process notepad -ErrorAction Stop | Select-Object -First 1
$shell = New-Object -ComObject WScript.Shell
if (-not $shell.AppActivate($process.Id)) {
  throw "Could not activate Notepad"
}

Use keyboard input only after activation succeeds. Never use keyboard input to trigger a consequential action prohibited above.

Troubleshooting

• An empty UI Automation tree can mean the target runs at a higher integrity level. Do not bypass Windows security boundaries. Ask the user to run both apps at the same privilege level if appropriate.
• App names, window titles, and control names can be localized. Prefer process IDs and automation IDs.
• Packaged apps may launch through an AppUserModelId rather than a stable executable. Discover them with Get-StartApps.
• host_bash is non-interactive. Do not use commands that wait for terminal input or depend on a PowerShell profile.

Details