diff --git a/scripts/common.ps1 b/scripts/common.ps1
index 296e6b0b..20b504c3 100644
--- a/scripts/common.ps1
+++ b/scripts/common.ps1
@@ -588,6 +588,42 @@ function Get-LiveConfigValueMap {
     return $values
 }
 
+function Get-PortableConfigDrift {
+    param(
+        [string]$Source,
+        [string]$Destination
+    )
+
+    $live = [System.Collections.Generic.Dictionary[string, string]]::new(
+        [System.StringComparer]::Ordinal
+    )
+    if (Test-Path -LiteralPath $Destination -PathType Leaf) {
+        $live = Get-LiveConfigValueMap -Path $Destination
+    }
+    foreach ($entry in Get-PortableConfigEntries -Path $Source) {
+        $identity = "$($entry.Section)`n$($entry.Key)"
+        if (-not $live.ContainsKey($identity)) {
+            $state = "missing"
+        }
+        elseif ($live[$identity] -ne $entry.Value) {
+            $state = "differs"
+        }
+        else {
+            continue
+        }
+        $key = if ($entry.Section) {
+            "$($entry.Section).$($entry.Key)"
+        }
+        else {
+            $entry.Key
+        }
+        [pscustomobject]@{
+            Key = $key
+            State = $state
+        }
+    }
+}
+
 function Merge-PortableConfig {
     param(
         [string]$Source,
@@ -671,14 +707,7 @@ function Test-PortableConfigInSync {
     if (-not (Test-Path -LiteralPath $Destination -PathType Leaf)) {
         return $false
     }
-    $live = Get-LiveConfigValueMap -Path $Destination
-    foreach ($entry in Get-PortableConfigEntries -Path $Source) {
-        $identity = "$($entry.Section)`n$($entry.Key)"
-        if (-not $live.ContainsKey($identity) -or $live[$identity] -ne $entry.Value) {
-            return $false
-        }
-    }
-    return $true
+    return @(Get-PortableConfigDrift -Source $Source -Destination $Destination).Count -eq 0
 }
 
 function Copy-PortableItem {
diff --git a/scripts/install.ps1 b/scripts/install.ps1
index 3c58a180..126817f3 100644
--- a/scripts/install.ps1
+++ b/scripts/install.ps1
@@ -47,6 +47,14 @@ if (-not $Apply) {
     else {
         foreach ($state in $changes) {
             Write-Host "  $($state.Item.RepoPath) -> $($state.Item.LivePath)"
+            if ($state.Item.Type -eq "config" -and $state.Exists) {
+                foreach ($entry in @(Get-PortableConfigDrift `
+                    -Source $state.Item.RepoPath `
+                    -Destination $state.Item.LivePath
+                )) {
+                    Write-Host "    reviewed config key $($entry.State): $($entry.Key)"
+                }
+            }
         }
     }
     Write-Host ""
diff --git a/scripts/test-all.ps1 b/scripts/test-all.ps1
index 1670d4be..d019a857 100644
--- a/scripts/test-all.ps1
+++ b/scripts/test-all.ps1
@@ -36,17 +36,49 @@ function Assert-TestFileContains {
     }
 }
 
+function Assert-TestDriftOutput {
+    param([string]$Text)
+
+    foreach ($expected in @(
+        "reviewed config key differs: model_reasoning_effort"
+        "reviewed config key missing: features.goals"
+    )) {
+        if (-not $Text.Contains($expected)) {
+            throw "expected output to contain: $expected"
+        }
+    }
+    foreach ($unexpected in @(
+        "machine_setting"
+        "machine-sensitive-preview-value"
+    )) {
+        if ($Text.Contains($unexpected)) {
+            throw "expected output not to contain: $unexpected"
+        }
+    }
+}
+
 $testRoot = Join-Path ([System.IO.Path]::GetTempPath()) "compass-test-$([guid]::NewGuid().ToString('N'))"
 $codexHome = Join-Path $testRoot "codex"
 $agentsHome = Join-Path $testRoot "agents"
 $claudeHome = Join-Path $testRoot "claude"
 
 try {
+    . "$PSScriptRoot\common.ps1"
+
+    $emptyConfigPath = Join-Path $testRoot "empty-config.toml"
+    $directoryTarget = Join-Path $testRoot "config-directory"
+    Write-TestFile -Path $emptyConfigPath -Content ""
+    New-Item -ItemType Directory -Path $directoryTarget | Out-Null
+    if (Test-PortableConfigInSync -Source $emptyConfigPath -Destination $directoryTarget) {
+        throw "config directory target reported in sync"
+    }
+
     $machineLabel = "preserve caf$([char]0x00E9)"
     Write-TestFile -Path (Join-Path $codexHome "AGENTS.md\local.txt") -Content "preserve this backup`n"
     Write-TestFile -Path (Join-Path $codexHome "auth.json") -Content "leave unlisted state alone`n"
     Write-TestFile -Path (Join-Path $codexHome "config.toml") -Content @"
 MODEL = "machine-specific"
+model_reasoning_effort = "machine-sensitive-preview-value"
 machine_setting = "$machineLabel"
 
 ["features"]
@@ -56,6 +88,30 @@ memories = false
 trust_level = "trusted"
 "@
 
+    $configPath = Join-Path $codexHome "config.toml"
+    $configBeforePreview = Get-Content -Raw -LiteralPath $configPath
+    $powerShellPath = (Get-Process -Id $PID).Path
+    $previewOutput = & $powerShellPath `
+        -NoProfile `
+        -ExecutionPolicy Bypass `
+        -File (Join-Path $PSScriptRoot "install.ps1") `
+        -CodexHome $codexHome `
+        -AgentsHome $agentsHome `
+        -ClaudeHome $claudeHome 2>&1 | Out-String
+    if ($LASTEXITCODE -ne 0) {
+        throw "install preview failed: $previewOutput"
+    }
+    if ((Get-Content -Raw -LiteralPath $configPath) -cne $configBeforePreview) {
+        throw "install preview changed live config"
+    }
+    Assert-TestDriftOutput -Text $previewOutput
+
+    $verifyOutput = & (Join-Path $PSScriptRoot "verify-live.ps1") `
+        -CodexHome $codexHome `
+        -AgentsHome $agentsHome `
+        -ClaudeHome $claudeHome 6>&1 | Out-String
+    Assert-TestDriftOutput -Text $verifyOutput
+
     & (Join-Path $PSScriptRoot "install.ps1") `
         -Apply `
         -CodexHome $codexHome `
diff --git a/scripts/verify-live.ps1 b/scripts/verify-live.ps1
index 607a3e92..e8dbafa7 100644
--- a/scripts/verify-live.ps1
+++ b/scripts/verify-live.ps1
@@ -20,7 +20,7 @@ $items = @(
         -ClaudeHome $claudeHome
 )
 $missing = New-Object System.Collections.Generic.List[string]
-$drift = New-Object System.Collections.Generic.List[string]
+$drift = New-Object System.Collections.Generic.List[object]
 
 foreach ($item in $items) {
     if (-not (Test-Path -LiteralPath $item.LivePath)) {
@@ -28,7 +28,7 @@ foreach ($item in $items) {
         continue
     }
     if (-not (Test-PortableItemInSync -Item $item)) {
-        $drift.Add($item.LivePath)
+        $drift.Add($item)
     }
 }
 
@@ -48,8 +48,16 @@ if ($missing.Count -gt 0) {
 if ($drift.Count -gt 0) {
     Write-Host ""
     Write-Host "drift:"
-    foreach ($path in $drift) {
-        Write-Host "  $path"
+    foreach ($item in $drift) {
+        Write-Host "  $($item.LivePath)"
+        if ($item.Type -eq "config") {
+            foreach ($entry in @(Get-PortableConfigDrift `
+                -Source $item.RepoPath `
+                -Destination $item.LivePath
+            )) {
+                Write-Host "    reviewed config key $($entry.State): $($entry.Key)"
+            }
+        }
     }
 }