diff --git a/openless-all/app/scripts/windows-ime-build.ps1 b/openless-all/app/scripts/windows-ime-build.ps1
new file mode 100644
index 00000000..33aa38a5
--- /dev/null
+++ b/openless-all/app/scripts/windows-ime-build.ps1
@@ -0,0 +1,55 @@
+param(
+  [ValidateSet("Debug", "Release")]
+  [string]$Configuration = "Release"
+)
+
+$ErrorActionPreference = "Stop"
+
+function Find-MSBuild {
+  $cmd = Get-Command MSBuild.exe -ErrorAction SilentlyContinue
+  if ($cmd) {
+    return $cmd.Source
+  }
+
+  $vswhere = Join-Path ${env:ProgramFiles(x86)} "Microsoft Visual Studio\Installer\vswhere.exe"
+  if (Test-Path $vswhere) {
+    $found = & $vswhere -latest -products * -requires Microsoft.Component.MSBuild -find "MSBuild\Current\Bin\MSBuild.exe" 2>$null |
+      Select-Object -First 1
+    if ($found -and (Test-Path $found)) {
+      return $found
+    }
+  }
+
+  $candidates = @(
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\MSBuild.exe",
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\BuildTools\MSBuild\Current\Bin\MSBuild.exe"
+  )
+  foreach ($candidate in $candidates) {
+    if (Test-Path $candidate) {
+      return $candidate
+    }
+  }
+
+  throw "MSBuild.exe not found. Install Visual Studio Build Tools or run from Developer PowerShell."
+}
+
+$appRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
+$solution = Join-Path $appRoot "windows-ime\OpenLessIme.sln"
+$dll = Join-Path $appRoot "windows-ime\x64\$Configuration\OpenLessIme.dll"
+$msbuild = Find-MSBuild
+
+if (-not (Test-Path $solution)) {
+  throw "Solution not found: $solution"
+}
+
+Write-Host "[build] $Configuration x64"
+& $msbuild $solution /p:Configuration=$Configuration /p:Platform=x64
+if ($LASTEXITCODE -ne 0) {
+  throw "OpenLessIme build failed with exit code $LASTEXITCODE"
+}
+
+if (-not (Test-Path $dll)) {
+  throw "OpenLessIme.dll was not produced: $dll"
+}
+
+Write-Host "[ok] $dll"
diff --git a/openless-all/app/scripts/windows-ime-register.ps1 b/openless-all/app/scripts/windows-ime-register.ps1
new file mode 100644
index 00000000..ce012685
--- /dev/null
+++ b/openless-all/app/scripts/windows-ime-register.ps1
@@ -0,0 +1,29 @@
+param(
+  [ValidateSet("Debug", "Release")]
+  [string]$Configuration = "Release"
+)
+
+$ErrorActionPreference = "Stop"
+
+function Get-Regsvr32x64 {
+  $sysnative = Join-Path $env:WINDIR "Sysnative\regsvr32.exe"
+  if (Test-Path $sysnative) {
+    return $sysnative
+  }
+  return (Join-Path $env:WINDIR "System32\regsvr32.exe")
+}
+
+$appRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
+$dll = Join-Path $appRoot "windows-ime\x64\$Configuration\OpenLessIme.dll"
+
+if (-not (Test-Path $dll)) {
+  & (Join-Path $PSScriptRoot "windows-ime-build.ps1") -Configuration $Configuration
+}
+
+$regsvr32 = Get-Regsvr32x64
+& $regsvr32 /s $dll
+if ($LASTEXITCODE -ne 0) {
+  throw "regsvr32 failed with exit code $LASTEXITCODE"
+}
+
+Write-Host "[ok] OpenLess TSF IME registered"
diff --git a/openless-all/app/scripts/windows-ime-unregister.ps1 b/openless-all/app/scripts/windows-ime-unregister.ps1
new file mode 100644
index 00000000..1e2a9532
--- /dev/null
+++ b/openless-all/app/scripts/windows-ime-unregister.ps1
@@ -0,0 +1,30 @@
+param(
+  [ValidateSet("Debug", "Release")]
+  [string]$Configuration = "Release"
+)
+
+$ErrorActionPreference = "Stop"
+
+function Get-Regsvr32x64 {
+  $sysnative = Join-Path $env:WINDIR "Sysnative\regsvr32.exe"
+  if (Test-Path $sysnative) {
+    return $sysnative
+  }
+  return (Join-Path $env:WINDIR "System32\regsvr32.exe")
+}
+
+$appRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
+$dll = Join-Path $appRoot "windows-ime\x64\$Configuration\OpenLessIme.dll"
+
+if (-not (Test-Path $dll)) {
+  Write-Host "[skip] OpenLessIme.dll not found: $dll"
+  exit 0
+}
+
+$regsvr32 = Get-Regsvr32x64
+& $regsvr32 /u /s $dll
+if ($LASTEXITCODE -ne 0) {
+  throw "regsvr32 /u failed with exit code $LASTEXITCODE"
+}
+
+Write-Host "[ok] OpenLess TSF IME unregistered"
diff --git a/openless-all/app/scripts/windows-preflight.ps1 b/openless-all/app/scripts/windows-preflight.ps1
index edee735e..1176f335 100644
--- a/openless-all/app/scripts/windows-preflight.ps1
+++ b/openless-all/app/scripts/windows-preflight.ps1
@@ -1,5 +1,5 @@
 param(
-  [ValidateSet("all", "msvc", "gnu")]
+  [ValidateSet("all", "msvc", "gnu", "ime")]
   [string]$Toolchain = "all"
 )
 
@@ -17,6 +17,34 @@ function Test-Command($Name) {
   return $false
 }
 
+function Find-MSBuild {
+  $cmd = Get-Command MSBuild.exe -ErrorAction SilentlyContinue
+  if ($cmd) {
+    return $cmd.Source
+  }
+
+  $vswhere = Join-Path ${env:ProgramFiles(x86)} "Microsoft Visual Studio\Installer\vswhere.exe"
+  if (Test-Path $vswhere) {
+    $found = & $vswhere -latest -products * -requires Microsoft.Component.MSBuild -find "MSBuild\Current\Bin\MSBuild.exe" 2>$null |
+      Select-Object -First 1
+    if ($found -and (Test-Path $found)) {
+      return $found
+    }
+  }
+
+  $candidates = @(
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\MSBuild.exe",
+    "${env:ProgramFiles}\Microsoft Visual Studio\2022\BuildTools\MSBuild\Current\Bin\MSBuild.exe"
+  )
+  foreach ($candidate in $candidates) {
+    if (Test-Path $candidate) {
+      return $candidate
+    }
+  }
+
+  return $null
+}
+
 function Find-Kernel32Lib {
   $kitsRoot = Join-Path ${env:ProgramFiles(x86)} "Windows Kits\10\Lib"
   if (-not (Test-Path $kitsRoot)) {
@@ -100,6 +128,28 @@ if ($Toolchain -eq "all" -or $Toolchain -eq "gnu") {
   }
 }
 
+if ($Toolchain -eq "all" -or $Toolchain -eq "ime") {
+  Write-Host ""
+  Write-Host "== Windows IME route =="
+  $msbuild = Find-MSBuild
+  if ($msbuild) {
+    Write-Host "[ok] MSBuild.exe -> $msbuild"
+  } else {
+    Write-Host "[missing] MSBuild.exe"
+    Write-Host "[hint] Install Visual Studio Build Tools workload 'Desktop development with C++'."
+    $failed = $true
+  }
+
+  $kernel32 = Find-Kernel32Lib
+  if ($kernel32) {
+    Write-Host "[ok] kernel32.lib -> $kernel32"
+  } else {
+    Write-Host "[missing] kernel32.lib"
+    Write-Host "[hint] Install a Windows 10/11 SDK with x64 libraries."
+    $failed = $true
+  }
+}
+
 if ($failed) {
   exit 1
 }