diff --git a/.conductor/registry/scripts/worktree-manager.ps1 b/.conductor/registry/scripts/worktree-manager.ps1
index 585e47f..689c263 100644
--- a/.conductor/registry/scripts/worktree-manager.ps1
+++ b/.conductor/registry/scripts/worktree-manager.ps1
@@ -251,7 +251,8 @@ try {
         exit 0
     }
 
-    # teardown
+    # teardown — retry-with-backoff for transient file-handle races on Windows.
+    # Mirrors the delay schedule in GitWorktreeDeleter.cs:RemoveWithRetryAsync.
     if (-not (Test-Path $worktreePath)) {
         # Idempotent: nothing to clean up.
         $envelope.success = $true
@@ -259,10 +260,21 @@ try {
         exit 0
     }
 
-    $output = & git worktree remove --force $worktreePath 2>&1
-    if ($LASTEXITCODE -ne 0) {
+    $wtDelays = @(0, 200, 500, 1000)
+    $wtOutput = $null
+    $wtSuccess = $false
+    foreach ($wtDelayMs in $wtDelays) {
+        if ($wtDelayMs -gt 0) { Start-Sleep -Milliseconds $wtDelayMs }
+        $wtOutput = & git worktree remove --force $worktreePath 2>&1
+        if ($LASTEXITCODE -eq 0 -or -not (Test-Path $worktreePath)) {
+            $wtSuccess = $true
+            break
+        }
+    }
+
+    if (-not $wtSuccess) {
         $envelope.error_code = 'worktree_remove_failed'
-        $envelope.error_message = "git worktree remove failed: $($output -join "`n")"
+        $envelope.error_message = "git worktree remove failed: $($wtOutput -join "`n")"
         $envelope | ConvertTo-Json -Compress
         exit 0
     }
diff --git a/scripts/Invoke-PolyphonySdlc.ps1 b/scripts/Invoke-PolyphonySdlc.ps1
index b8202ed..a072a23 100644
--- a/scripts/Invoke-PolyphonySdlc.ps1
+++ b/scripts/Invoke-PolyphonySdlc.ps1
@@ -217,6 +217,22 @@ if ($Intent -ne 'reset') {
 
 $script:LayoutDoc        = 'docs/per-run-worktree-layout.md'
 
+# ─── Helper: sanitize $Comment against shell-injection surfaces ──────────────
+#
+# $Comment flows into a here-string that is passed to pwsh -Command in the
+# reset-detach path. Newlines (CR, LF, backtick-continuations) and bare
+# backticks can break out of the embedded command string and inject arbitrary
+# PowerShell. Strip them at the boundary before any interpolation.
+
+function Get-SanitizedComment {
+    param([Parameter(Mandatory)][AllowEmptyString()][string]$Value)
+    # Strip CR and LF characters.
+    $sanitized = $Value -replace '[\r\n]', ''
+    # Escape backticks (PowerShell escape character) so they are literal.
+    $sanitized = $sanitized -replace '`', '``'
+    return $sanitized
+}
+
 # ─── Helper: canonical path comparison (boundary-aware, OS-aware) ─────────────
 
 function Get-CanonicalPath {
@@ -313,6 +329,9 @@ if ($Intent -eq 'reset') {
         }
     }
 
+    # Sanitize $Comment at the boundary before any shell interpolation.
+    $Comment = Get-SanitizedComment -Value $Comment
+
     # Auto-detect platform from origin for gh-identity pinning. The reset
     # workflow itself does not take a platform input — the projection reset
     # executor resolves the platform internally (the PR-abandonment leg
@@ -830,10 +849,15 @@ $detectedPlatform     = $null
 $detectedRepository   = $null
 $detectedRepoOrg      = $null
 $detectedRepoProject  = $null
-$remoteUrl = & git -C $mainWorktree remote get-url origin 2>&1
-if ($LASTEXITCODE -ne 0 -or [string]::IsNullOrWhiteSpace($remoteUrl)) {
-    $remoteUrl = $null
-    $global:LASTEXITCODE = 0
+Push-Location -LiteralPath $mainWorktree
+try {
+    $remoteUrl = & git remote get-url origin 2>&1
+    if ($LASTEXITCODE -ne 0 -or [string]::IsNullOrWhiteSpace($remoteUrl)) {
+        $remoteUrl = $null
+        $global:LASTEXITCODE = 0
+    }
+} finally {
+    Pop-Location
 }
 
 if ($remoteUrl) {