diff --git a/.github/workflows/cli-arguments.yml b/.github/workflows/cli-arguments.yml
new file mode 100644
index 00000000..ba0108bd
--- /dev/null
+++ b/.github/workflows/cli-arguments.yml
@@ -0,0 +1,35 @@
+name: Public CLI unknown argument rejection
+on:
+  push:
+    branches: ['**']
+  pull_request:
+  workflow_dispatch:
+permissions:
+  contents: read
+jobs:
+  cli-arguments:
+    timeout-minutes: 15
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-2022, windows-2025]
+        engine: [powershell, pwsh]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
+      - name: Windows PowerShell 5.1 process and native state checks
+        if: matrix.engine == 'powershell'
+        shell: powershell
+        run: ./tests/CliArguments.Tests.ps1
+      - name: PowerShell 7 process and native state checks
+        if: matrix.engine == 'pwsh'
+        shell: pwsh
+        run: ./tests/CliArguments.Tests.ps1
+      - name: Retain native before and after observations
+        if: always()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02
+        with:
+          name: cli-arguments-${{ matrix.os }}-${{ matrix.engine }}
+          path: ${{ runner.temp }}/wela-cli-arguments.json
+          if-no-files-found: error
+          retention-days: 7
diff --git a/CHANGELOG-Japanese.md b/CHANGELOG-Japanese.md
index d0e1cea8..ec0710f7 100644
--- a/CHANGELOG-Japanese.md
+++ b/CHANGELOG-Japanese.md
@@ -4,6 +4,8 @@
 
 **改善:**
 
+- 従来の設定コマンドでも、未対応の `-WhatIf` や入力ミスなどの未認識引数を実行前に拒否するようにしました。`-ErrorAction` や `-Verbose` などの PowerShell 共通パラメーターも拒否するため、自動化ラッパーへの影響をヘルプと診断に明記しました。正しい位置指定引数と文書化された `-DryRun` の動作は維持し、Windows PowerShell 5.1 と PowerShell 7 で公開CLIを検証します。 (@Shirofune-Security)
+
 - Windows PowerShell 5.1 と PowerShell 7、使い捨ての Server 2022/2025 で標準チャネル設定の公開CLIを検証するテストを追加しました。有効化・サイズ・CAPI2読み取り専用権限の適用、既存記述子と大きいバッファーの保持、変更前記録、DryRun、再実行時の無変更、元設定への復元を確認し、ハッシュ付きの証拠を保存します。転送・保存期間・Sigmaの検証は別途必要です。 (@Shirofune-Security)
 
 - 完了済みのファイアウォールテキストログ設定を1プロファイルずつ復元する、明示的な `firewall-recovery` を追加しました。元の記録・結果、確認済み計画ハッシュ、実行者・ソース、永続記録と変更前後の確認により、PersistentStore の4項目だけを復元し、強制設定・他のプロファイル・ルールとフィルターを保持します。実効ポリシーを別に報告し、途中失敗を未検証として扱い、自動ロールバックや Sigma 加点は行いません。使い捨て環境の公開 CLI で設定、変更検出、復元、冪等性、完全な後始末を検証します。(関連 #375) (@Shirofune-Security)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08966619..401ee995 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,8 @@
 
 **Improvements:**
 
+- Reject unbound command-line arguments before dispatch, including unsupported `-WhatIf` and misspelled options on legacy configuration commands. PowerShell common parameters such as `-ErrorAction` and `-Verbose` are also rejected; help and diagnostics explain the automation-wrapper compatibility change. Valid positional arguments and documented `-DryRun` behavior are preserved. Public CLI regressions cover both Windows PowerShell 5.1 and PowerShell 7. (@Shirofune-Security)
+
 - Added disposable Server 2022/2025 validation of public native channel configuration under Windows PowerShell 5.1 and PowerShell 7. Tests apply enable/size controls and the explicit CAPI2 read-only grant, verify descriptor preservation, journals, larger buffers, DryRun and idempotence, and retain hashed native evidence with exact fixture cleanup. Forwarding, retention-duration and Sigma validation remain separate. (@Shirofune-Security)
 
 - Added opt-in `firewall-recovery` for one completed firewall text-log operation. Strict original journal/result matching, reviewed plan hashes, native operator/source guards, durable receipts and exact four-field PersistentStore restoration preserve enforcement, other profiles and bounded rule/filter configuration. Effective policy stays separately reported; partial writes remain unverified without automatic rollback or Sigma credit. Disposable public-CLI tests cover configuration, drift refusal, recovery, idempotence and exact cleanup. (Related #375) (@Shirofune-Security)
diff --git a/WELA.ps1 b/WELA.ps1
index fd44c7a9..8b5b1fc7 100644
--- a/WELA.ps1
+++ b/WELA.ps1
@@ -1941,6 +1941,10 @@ function Get-WelaUserProfiles {
 }
 
 $usage = @"
+WELA.ps1 accepts only its documented script parameters. PowerShell common parameters
+(-ErrorAction, -Verbose, -WarningAction, -InformationAction) are not supported.
+Remove these options from automation wrappers; check WELA's exit code instead.
+
 Usage:
   ./WELA.ps1 dns-analytical -Help  # Dedicated DNS Server direct-channel lifecycle
   ./WELA.ps1 wec-runtime -WecRuntimeId subscription-id -ResultsPath new-runtime.json
@@ -2231,6 +2235,13 @@ if ($Cmd -ne 'ldap-diagnostics' -and @($PSBoundParameters.Keys | Where-Object {
     throw 'LDAP options require the dedicated ldap-diagnostics command. No command was run.'
 }
 
+# Plain scripts retain unknown named options in $args. Check them before every
+# dispatch, including the profile shortcut, so an unsupported -WhatIf or typo
+# cannot accidentally reach a writer. Keep dedicated option diagnostics above.
+if ($args.Count -gt 0) {
+    throw 'Unsupported trailing arguments. PowerShell common parameters (for example -ErrorAction or -Verbose) are not supported. Check -Help for documented options; no command was run.'
+}
+
 if ($Profile -and $Cmd.ToLower() -in @('plan', 'audit', 'audit-settings', 'configure') -and -not $Help) {
     Invoke-WelaProfileCommand -Command $Cmd.ToLower()
     return
@@ -2688,6 +2699,7 @@ switch ($Cmd.ToLower()) {
             Write-Host "  -BackupPath  New directory for the pre-change recovery journal (unique default beside WELA)"
             Write-Host "  -ResultsPath Save structured per-control outcomes as JSON"
             Write-Host ""
+            Write-Host "PowerShell common parameters (-ErrorAction, -Verbose, -WarningAction, -InformationAction) are not supported. Remove them from wrappers and check the exit code."
             Write-Host "Without -Profile, configure applies the YamatoSecurity native logging settings. -Profile applies advanced audit policy and its precedence prerequisite. -DryRun and recovery/results options work with both."
             Write-Host ""
             return
diff --git a/docs/configuration-results.md b/docs/configuration-results.md
index a3551c61..1f700726 100644
--- a/docs/configuration-results.md
+++ b/docs/configuration-results.md
@@ -18,6 +18,10 @@ or result-file error also exits with status 1.
 .\WELA.ps1 configure -Auto -ResultsPath .\results.json
 ```
 
+Unknown named options and other arguments left unbound by PowerShell are rejected before command dispatch. This includes unsupported `-WhatIf`, `-Confirm` and misspelled `-DryRun` options, even with `-Auto`. Use each command's `-Help` for its supported preview options; `-DryRun` is accepted only where documented. Valid positional binding and PowerShell's unambiguous parameter abbreviations remain supported.
+
+`WELA.ps1` is a plain PowerShell script and does not accept PowerShell common parameters such as `-ErrorAction`, `-Verbose`, `-WarningAction` or `-InformationAction`. Earlier versions silently ignored those unbound options; they now produce exit code 1 before any command runs, including read-only commands. Remove them from automation wrappers and use WELA's exit code and structured results to check the outcome. The explicitly declared WELA `-Debug` switch remains supported where documented.
+
 Keep the complete WELA directory, including `scripts/Configuration.ps1`. Choose a
 recovery path whose parent directory is writable only by the operators who manage
 these settings. The backup directory must not already exist. Without `-BackupPath`,
diff --git a/tests/CliArguments.Tests.ps1 b/tests/CliArguments.Tests.ps1
new file mode 100644
index 00000000..9f28df52
--- /dev/null
+++ b/tests/CliArguments.Tests.ps1
@@ -0,0 +1,70 @@
+# Public process-boundary regression: no mocked dispatcher or Windows writers.
+$ErrorActionPreference = 'Stop'
+$repo = Split-Path $PSScriptRoot -Parent
+$engine = (Get-Process -Id $PID).Path
+$count = 0
+$root = Join-Path ([IO.Path]::GetTempPath()) ('wela-cli-arguments-' + [guid]::NewGuid().ToString('N'))
+$null = New-Item -ItemType Directory -Path $root
+function Assert($Value, $Message) { if (-not $Value) { throw $Message }; $script:count++ }
+function Invoke-Case([string[]]$Arguments, [int]$Expected, [string]$Pattern) {
+    $prior = $ErrorActionPreference
+    try {
+        $ErrorActionPreference = 'Continue'
+        $output = & $engine -NoLogo -NoProfile -NonInteractive -File "$repo/WELA.ps1" @Arguments 2>&1 | Out-String
+        $code = $LASTEXITCODE
+    } finally { $ErrorActionPreference = $prior }
+    Assert ($code -eq $Expected -and $output -match $Pattern) "Unexpected public CLI exit/output [$code]: $output"
+}
+$isWindowsHost = [Environment]::OSVersion.Platform -eq [PlatformID]::Win32NT
+function Read-NativeState {
+    $logs = @('Security','System','Application','ForwardedEvents','Microsoft-Windows-CAPI2/Operational')
+    $state = [ordered]@{ Audit = Get-WelaEffectiveAuditPolicy; Channels = @() }
+    foreach ($name in $logs) { $state.Channels += Get-WelaNativeChannel $name }
+    return ($state | ConvertTo-Json -Depth 12 -Compress)
+}
+try {
+    if ($isWindowsHost) {
+        Import-Module "$repo/modules/AuditProfiles.psm1" -Force
+        Import-Module "$repo/modules/NativeProviders.psm1" -Force
+        $before = Read-NativeState
+    }
+    # These previously reached legacy writers, including the profile fast path.
+    $commands = @(
+        @('configure','-Auto'),
+        @('configure','-Profile','wela-2.2.0','-Auto'),
+        @('configure-eventlogs','-LogProfile','asd-collector-archive-2021-10','-ApplyLogMode','-Auto'),
+        @('configure-sacl','-Auto'),
+        @('channel-settings','-ChannelAction','Configure','-GrantEventLogReaders','-Auto'),
+        @('powershell-transcription','-TranscriptionAction','Configure','-Auto'),
+        @('firewall-logging','-FirewallAction','Configure','-Auto'),
+        @('smb-auditing','-SmbAction','Configure','-Auto'),
+        @('audit-integrity','-IntegrityAction','Configure','-Auto'),
+        @('provider-packs','-ProviderAction','Configure','-Auto'),
+        @('wec-collector','-WefAction','Configure','-Auto'),
+        @('audit-settings','-Help')
+    )
+    foreach ($command in $commands) {
+        foreach ($unknown in @('-WhatIf','-DryRnu')) {
+            Invoke-Case ($command + @('-BackupPath',"$root/journal",'-ResultsPath',"$root/result.json",$unknown)) 1 'Unsupported trailing arguments'
+            Assert (-not (Test-Path "$root/journal") -and -not (Test-Path "$root/result.json")) 'Rejected arguments must not create journals/results'
+        }
+    }
+    # Unknown argument values are deliberately omitted from WELA's diagnostic.
+    Invoke-Case @('configure','-Auto','-UnrecognizedOption','opaque-value') 1 'Unsupported trailing arguments'
+    Invoke-Case @('configure','-Help','-WhatIf:$false') 1 'Unsupported trailing arguments'
+    Invoke-Case @('-WhatIf','configure','-Auto') 1 'Unsupported trailing arguments'
+    # Preserve documented named/positional binding, help, abbreviations and DryRun.
+    Invoke-Case @('configure','-Help','-Auto','-DryRun') 0 'Read live state'
+    Invoke-Case @('-Cmd','configure','-Help') 0 'Usage:'
+    Invoke-Case @('configure','std','-Help') 0 'Usage:'
+    Invoke-Case @('configure','-Hel') 0 'Usage:'
+    Invoke-Case @('profiles') 0 'wela-2.2.0'
+    Invoke-Case @('failed-logon-probe','-FailedLogonAction','Run','-WhatIf') 1 'only dedicated'
+    if ($isWindowsHost) {
+        Assert ((Read-NativeState) -ceq $before) 'Actual audit masks and native channel settings must remain unchanged'
+        $evidence = [ordered]@{ Status='Passed'; Engine=$PSVersionTable.PSVersion.ToString(); OS=[Environment]::OSVersion.Version.ToString(); StateUnchanged=$true; Before=($before|ConvertFrom-Json); After=((Read-NativeState)|ConvertFrom-Json) }
+        if ($env:RUNNER_TEMP) { $evidence | ConvertTo-Json -Depth 16 | Set-Content (Join-Path $env:RUNNER_TEMP 'wela-cli-arguments.json') -Encoding UTF8 }
+    }
+    Write-Host "PASS: $count public CLI argument assertions."
+} finally { Remove-Item -LiteralPath $root -Recurse -Force }
+$global:LASTEXITCODE = 0
diff --git a/website/docs/resources/changelog.ja.md b/website/docs/resources/changelog.ja.md
index 708d6ab9..92a34bc1 100644
--- a/website/docs/resources/changelog.ja.md
+++ b/website/docs/resources/changelog.ja.md
@@ -7,6 +7,8 @@
 
 **改善:**
 
+- 従来の設定コマンドでも、未対応の `-WhatIf` や入力ミスなどの未認識引数を実行前に拒否するようにしました。`-ErrorAction` や `-Verbose` などの PowerShell 共通パラメーターも拒否するため、自動化ラッパーへの影響をヘルプと診断に明記しました。正しい位置指定引数と文書化された `-DryRun` の動作は維持し、Windows PowerShell 5.1 と PowerShell 7 で公開CLIを検証します。 (@Shirofune-Security)
+
 - Windows PowerShell 5.1 と PowerShell 7、使い捨ての Server 2022/2025 で標準チャネル設定の公開CLIを検証するテストを追加しました。有効化・サイズ・CAPI2読み取り専用権限の適用、既存記述子と大きいバッファーの保持、変更前記録、DryRun、再実行時の無変更、元設定への復元を確認し、ハッシュ付きの証拠を保存します。転送・保存期間・Sigmaの検証は別途必要です。 (@Shirofune-Security)
 
 - 完了済みのファイアウォールテキストログ設定を1プロファイルずつ復元する、明示的な `firewall-recovery` を追加しました。元の記録・結果、確認済み計画ハッシュ、実行者・ソース、永続記録と変更前後の確認により、PersistentStore の4項目だけを復元し、強制設定・他のプロファイル・ルールとフィルターを保持します。実効ポリシーを別に報告し、途中失敗を未検証として扱い、自動ロールバックや Sigma 加点は行いません。使い捨て環境の公開 CLI で設定、変更検出、復元、冪等性、完全な後始末を検証します。(関連 #375) (@Shirofune-Security)
diff --git a/website/docs/resources/changelog.md b/website/docs/resources/changelog.md
index 49cf7543..69f307a3 100644
--- a/website/docs/resources/changelog.md
+++ b/website/docs/resources/changelog.md
@@ -7,6 +7,8 @@
 
 **Improvements:**
 
+- Reject unbound command-line arguments before dispatch, including unsupported `-WhatIf` and misspelled options on legacy configuration commands. PowerShell common parameters such as `-ErrorAction` and `-Verbose` are also rejected; help and diagnostics explain the automation-wrapper compatibility change. Valid positional arguments and documented `-DryRun` behavior are preserved. Public CLI regressions cover both Windows PowerShell 5.1 and PowerShell 7. (@Shirofune-Security)
+
 - Added disposable Server 2022/2025 validation of public native channel configuration under Windows PowerShell 5.1 and PowerShell 7. Tests apply enable/size controls and the explicit CAPI2 read-only grant, verify descriptor preservation, journals, larger buffers, DryRun and idempotence, and retain hashed native evidence with exact fixture cleanup. Forwarding, retention-duration and Sigma validation remain separate. (@Shirofune-Security)
 
 - Added opt-in `firewall-recovery` for one completed firewall text-log operation. Strict original journal/result matching, reviewed plan hashes, native operator/source guards, durable receipts and exact four-field PersistentStore restoration preserve enforcement, other profiles and bounded rule/filter configuration. Effective policy stays separately reported; partial writes remain unverified without automatic rollback or Sigma credit. Disposable public-CLI tests cover configuration, drift refusal, recovery, idempotence and exact cleanup. (Related #375) (@Shirofune-Security)