fix(agent99): harden runtime deploy rollback

agent99-deploy.ps1

@@ -18,6 +18,7 @@ $BackupDir = Join-Path $DeployRoot "backup-$stamp"
 $ManifestPath = Join-Path $StateDir "runtime-manifest.json"
 $EvidencePath = Join-Path $EvidenceDir "agent99-deploy-$stamp.json"
 $script:ConfigMigrations = @()
+$script:RuntimeCopyRetries = @()
 
 $runtimeFiles = @(
   "agent99-bootstrap.ps1",
@@ -64,6 +65,29 @@ function Set-AgentProperty {
   }
 }
 
+function Copy-AgentRuntimeFileWithRetry {
+  param(
+    [string]$Source,
+    [string]$Destination,
+    [int]$MaxAttempts = 20,
+    [int]$DelayMilliseconds = 500
+  )
+  for ($attempt = 1; $attempt -le $MaxAttempts; $attempt += 1) {
+    try {
+      Copy-Item -Force $Source $Destination
+      return
+    } catch [System.IO.IOException] {
+      if ($attempt -ge $MaxAttempts) { throw }
+      $script:RuntimeCopyRetries += [pscustomobject]@{
+        file = Split-Path -Leaf $Destination
+        attempt = $attempt
+        reason = "file_in_use"
+      }
+      Start-Sleep -Milliseconds $DelayMilliseconds
+    }
+  }
+}
+
 function Write-DeployEvidence {
   param([bool]$Ok, [string]$Status, [string]$ErrorText, [object[]]$Files, [object]$TaskResult)
   New-Item -ItemType Directory -Force -Path $EvidenceDir | Out-Null
@@ -82,6 +106,8 @@ function Write-DeployEvidence {
     registerTasks = [bool]$RegisterTasks
     error = $ErrorText
     configMigrations = @($script:ConfigMigrations)
+    runtimeCopyRetryCount = @($script:RuntimeCopyRetries).Count
+    runtimeCopyRetries = @($script:RuntimeCopyRetries)
     files = $Files
     taskRegistration = $TaskResult
   } | ConvertTo-Json -Depth 10 | Set-Content -Path $EvidencePath -Encoding UTF8
@@ -92,7 +118,7 @@ function Restore-Agent99Deployment {
   foreach ($item in $Rows) {
     $backupPath = Join-Path $BackupDir $item.name
     if ($item.existed -and (Test-Path $backupPath)) {
-      Copy-Item -Force $backupPath $item.livePath
+      Copy-AgentRuntimeFileWithRetry $backupPath $item.livePath
     } elseif (-not $item.existed -and (Test-Path $item.livePath)) {
       Remove-Item -Force $item.livePath
     }
@@ -151,14 +177,6 @@ $promotionRows = @()
 $configBackedUp = $false
 $manifestBackedUp = $false
 try {
-  foreach ($name in $runtimeFiles) {
-    $livePath = Join-Path $BinDir $name
-    $existed = Test-Path $livePath
-    if ($existed) { Copy-Item -Force $livePath (Join-Path $BackupDir $name) }
-    $promotionRows += [pscustomobject]@{ name = $name; livePath = $livePath; existed = [bool]$existed }
-    Copy-Item -Force (Join-Path $StageDir $name) $livePath
-  }
-
   if (-not (Test-Path $ConfigPath)) { throw "Live Agent99 config not found: $ConfigPath" }
   Copy-Item -Force $ConfigPath (Join-Path $BackupDir "agent99.config.json")
   $configBackedUp = $true
@@ -167,6 +185,14 @@ try {
     $manifestBackedUp = $true
   }
 
+  foreach ($name in $runtimeFiles) {
+    $livePath = Join-Path $BinDir $name
+    $existed = Test-Path $livePath
+    if ($existed) { Copy-Item -Force $livePath (Join-Path $BackupDir $name) }
+    $promotionRows += [pscustomobject]@{ name = $name; livePath = $livePath; existed = [bool]$existed }
+    Copy-AgentRuntimeFileWithRetry (Join-Path $StageDir $name) $livePath
+  }
+
   $config = Get-Content $ConfigPath -Raw | ConvertFrom-Json
   Add-DefaultProperty $config "sshIdentityFile" (Join-Path $AgentRoot "keys\agent99_ed25519")
   Add-DefaultProperty $config "sshTransport" ([pscustomobject]@{})

apps/api/tests/test_agent99_transport_recovery_deploy_contract.py

@@ -164,6 +164,25 @@ def test_agent99_deployer_verifies_promoted_runtime_and_writes_revision() -> Non
         assert f'"{name}"' in bootstrap
 
 
+def test_agent99_deployer_backs_up_manifest_before_runtime_promotion() -> None:
+    deploy = DEPLOY.read_text(encoding="utf-8")
+    promotion = deploy[deploy.index("$configBackedUp = $false") :]
+    promotion = promotion[: promotion.index("$config = Get-Content $ConfigPath")]
+
+    assert promotion.index('Copy-Item -Force $ConfigPath') < promotion.index(
+        "foreach ($name in $runtimeFiles)"
+    )
+    assert promotion.index('Copy-Item -Force $ManifestPath') < promotion.index(
+        "foreach ($name in $runtimeFiles)"
+    )
+    assert 'Restore-Agent99Deployment $promotionRows $configBackedUp $manifestBackedUp' in deploy
+    assert "function Copy-AgentRuntimeFileWithRetry" in deploy
+    assert "MaxAttempts = 20" in deploy
+    assert 'reason = "file_in_use"' in deploy
+    assert "runtimeCopyRetryCount" in deploy
+    assert "Copy-AgentRuntimeFileWithRetry (Join-Path $StageDir $name) $livePath" in deploy
+
+
 def test_agent99_completion_callback_waits_for_durable_same_trace_readback() -> None:
     source = CONTROL.read_text(encoding="utf-8")
     deploy = DEPLOY.read_text(encoding="utf-8")