diff --git a/.github/workflows/ssh-relay-runtime-artifacts.yml b/.github/workflows/ssh-relay-runtime-artifacts.yml
index a4427b3fe85..15aec733174 100644
--- a/.github/workflows/ssh-relay-runtime-artifacts.yml
+++ b/.github/workflows/ssh-relay-runtime-artifacts.yml
@@ -1457,19 +1457,40 @@ jobs:
           $account = New-LocalUser -Name $fixtureUser -Password $password -PasswordNeverExpires `
             -UserMayNotChangePassword -AccountNeverExpires
           $userSid = $account.SID.Value
-          $creatorSid = [Security.Principal.WindowsIdentity]::GetCurrent().User.Value
           $systemSid = 'S-1-5-18'
           $administratorsSid = 'S-1-5-32-544'
 
-          function Set-FixtureAcl([string]$Path, [string[]]$Grants, [string[]]$ExpectedSids) {
-            & icacls.exe $Path /inheritance:r | Out-Host
-            if ($LASTEXITCODE -ne 0) { throw "Failed to remove inherited ACLs from $Path" }
-            # Why: key generation adds a creator ACE that /grant:r does not replace for other trustees.
-            & icacls.exe $Path /remove "*$creatorSid" | Out-Host
-            if ($LASTEXITCODE -ne 0) { throw "Failed to remove creator ACL from $Path" }
-            $arguments = @($Path, '/grant:r') + $Grants
-            & icacls.exe @arguments | Out-Host
-            if ($LASTEXITCODE -ne 0) { throw "Failed to grant fixture ACLs on $Path" }
+          function New-FixtureAclRule(
+            [string]$Sid,
+            [Security.AccessControl.FileSystemRights]$Rights,
+            [Security.AccessControl.InheritanceFlags]$InheritanceFlags
+          ) {
+            $identity = [Security.Principal.SecurityIdentifier]::new($Sid)
+            return [Security.AccessControl.FileSystemAccessRule]::new(
+              $identity,
+              $Rights,
+              $InheritanceFlags,
+              [Security.AccessControl.PropagationFlags]::None,
+              [Security.AccessControl.AccessControlType]::Allow
+            )
+          }
+          function Set-FixtureAcl(
+            [string]$Path,
+            [Security.AccessControl.FileSystemAccessRule[]]$AccessRules,
+            [string[]]$ExpectedSids
+          ) {
+            $item = Get-Item -LiteralPath $Path -Force
+            $security = if ($item.PSIsContainer) {
+              [Security.AccessControl.DirectorySecurity]::new()
+            } else {
+              [Security.AccessControl.FileSecurity]::new()
+            }
+            # Why: replacing the DACL atomically prevents drive-specific defaults from surviving.
+            $security.SetAccessRuleProtection($true, $false)
+            foreach ($accessRule in $AccessRules) {
+              [void]$security.AddAccessRule($accessRule)
+            }
+            Set-Acl -LiteralPath $Path -AclObject $security
             $acl = Get-Acl -LiteralPath $Path
             $rules = @($acl.Access)
             if (-not $acl.AreAccessRulesProtected -or @($rules | Where-Object { $_.IsInherited }).Count -ne 0) {
@@ -1490,14 +1511,19 @@ jobs:
             & icacls.exe $Path /setowner "*$OwnerSid" | Out-Host
             if ($LASTEXITCODE -ne 0) { throw "Failed to set fixture owner on $Path" }
           }
-          $systemFull = '*S-1-5-18:(OI)(CI)F'
-          $administratorsFull = '*S-1-5-32-544:(OI)(CI)F'
+          $noInheritance = [Security.AccessControl.InheritanceFlags]::None
+          $childInheritance = [Security.AccessControl.InheritanceFlags]::ContainerInherit -bor `
+            [Security.AccessControl.InheritanceFlags]::ObjectInherit
           $fixtureTrustees = @($systemSid, $administratorsSid, $userSid)
-          Set-FixtureAcl $fixture @($systemFull, $administratorsFull, "*$userSid`:RX") $fixtureTrustees
+          Set-FixtureAcl $fixture @(
+            (New-FixtureAclRule $systemSid FullControl $childInheritance),
+            (New-FixtureAclRule $administratorsSid FullControl $childInheritance),
+            (New-FixtureAclRule $userSid ReadAndExecute $noInheritance)
+          ) $fixtureTrustees
           Set-FixtureAcl $remoteRoot @(
-            $systemFull,
-            $administratorsFull,
-            "*$userSid`:(OI)(CI)M"
+            (New-FixtureAclRule $systemSid FullControl $childInheritance),
+            (New-FixtureAclRule $administratorsSid FullControl $childInheritance),
+            (New-FixtureAclRule $userSid Modify $childInheritance)
           ) $fixtureTrustees
 
           $clientKey = Join-Path $fixture 'client-key'
@@ -1509,14 +1535,14 @@ jobs:
           $authorizedKeys = Join-Path $fixture 'authorized_keys'
           Copy-Item -LiteralPath "$clientKey.pub" -Destination $authorizedKeys
           Set-FixtureAcl $authorizedKeys @(
-            '*S-1-5-18:F',
-            '*S-1-5-32-544:F',
-            "*$userSid`:R"
+            (New-FixtureAclRule $systemSid FullControl $noInheritance),
+            (New-FixtureAclRule $administratorsSid FullControl $noInheritance),
+            (New-FixtureAclRule $userSid Read $noInheritance)
           ) $fixtureTrustees
           Set-FixtureOwner $authorizedKeys $userSid
           Set-FixtureAcl $hostKey @(
-            '*S-1-5-18:F',
-            '*S-1-5-32-544:F'
+            (New-FixtureAclRule $systemSid FullControl $noInheritance),
+            (New-FixtureAclRule $administratorsSid FullControl $noInheritance)
           ) @($systemSid, $administratorsSid)
           Set-FixtureOwner $hostKey 'S-1-5-18'
 
@@ -1638,6 +1664,11 @@ jobs:
           $ownsFixture = Test-Path -LiteralPath (Join-Path $fixture 'fixture-owned')
           $ownsService = Test-Path -LiteralPath (Join-Path $fixture 'service-owned')
           $ownsAccount = Test-Path -LiteralPath (Join-Path $fixture 'account-owned')
+          $account = if ($ownsAccount) {
+            Get-LocalUser -Name $fixtureUser -ErrorAction SilentlyContinue
+          } else { $null }
+          $userSid = if ($account) { $account.SID.Value } else { $null }
+          $profilePath = Join-Path $env:SystemDrive "Users/$fixtureUser"
           try {
             $service = Get-CimInstance Win32_Service -Filter "Name='$serviceName'" -ErrorAction SilentlyContinue
             $servicePid = if ($service) { [int]$service.ProcessId } else { 0 }
@@ -1665,14 +1696,35 @@ jobs:
           $log = Join-Path $fixture 'sshd.log'
           if (Test-Path -LiteralPath $log) { Get-Content -LiteralPath $log -Tail 200 }
           try {
-            if ($ownsAccount -and (Get-LocalUser -Name $fixtureUser -ErrorAction SilentlyContinue)) {
+            if ($ownsAccount -and $userSid) {
+              $escapedSid = $userSid.Replace("'", "''")
+              $profileFailure = $null
+              for ($attempt = 1; $attempt -le 20; $attempt += 1) {
+                $profile = Get-CimInstance Win32_UserProfile -Filter "SID='$escapedSid'" `
+                  -ErrorAction SilentlyContinue
+                if (-not $profile) { break }
+                try {
+                  Remove-CimInstance -InputObject $profile -ErrorAction Stop
+                  $profileFailure = $null
+                } catch {
+                  $profileFailure = $_.Exception.Message
+                }
+                Start-Sleep -Milliseconds 500
+              }
+              if (Get-CimInstance Win32_UserProfile -Filter "SID='$escapedSid'" `
+                -ErrorAction SilentlyContinue) {
+                throw "Fixture profile did not settle within 10 seconds: $profileFailure"
+              }
+            }
+          } catch { $failures.Add("profile teardown: $($_.Exception.Message)") }
+          try {
+            if ($account) {
               Remove-LocalUser -Name $fixtureUser -ErrorAction Stop
             }
           } catch { $failures.Add("account teardown: $($_.Exception.Message)") }
           try {
-            $profile = Join-Path $env:SystemDrive "Users/$fixtureUser"
-            if ($ownsAccount -and (Test-Path -LiteralPath $profile)) {
-              Remove-Item -LiteralPath $profile -Recurse -Force -ErrorAction Stop
+            if ($ownsAccount -and (Test-Path -LiteralPath $profilePath)) {
+              Remove-Item -LiteralPath $profilePath -Recurse -Force -ErrorAction Stop
             }
             if ($ownsFixture -and (Test-Path -LiteralPath $fixture)) {
               Remove-Item -LiteralPath $fixture -Recurse -Force -ErrorAction Stop
@@ -1681,6 +1733,9 @@ jobs:
           if ($ownsAccount -and (Get-LocalUser -Name $fixtureUser -ErrorAction SilentlyContinue)) {
             $failures.Add('fixture account remains registered')
           }
+          if ($ownsAccount -and (Test-Path -LiteralPath $profilePath)) {
+            $failures.Add('fixture profile directory remains')
+          }
           if ($failures.Count -gt 0) { throw ($failures -join '; ') }
 
       - name: Upload unpublished artifact evidence
diff --git a/config/scripts/ssh-relay-runtime-workflow.test.mjs b/config/scripts/ssh-relay-runtime-workflow.test.mjs
index f3ec13d255b..273c61b10d0 100644
--- a/config/scripts/ssh-relay-runtime-workflow.test.mjs
+++ b/config/scripts/ssh-relay-runtime-workflow.test.mjs
@@ -179,8 +179,10 @@ describe('SSH relay runtime artifact workflow', () => {
     expect(start.run).toContain("if ($nativeFile.Name -eq 'libcrypto.dll') { continue }")
     expect(start.run).toContain("$signature.Status -ne 'Valid'")
     expect(start.run).toContain('CN=Microsoft Corporation')
-    expect(start.run).toContain('[Security.Principal.WindowsIdentity]::GetCurrent().User.Value')
-    expect(start.run).toContain('& icacls.exe $Path /remove "*$creatorSid"')
+    expect(start.run).toContain('[Security.AccessControl.DirectorySecurity]::new()')
+    expect(start.run).toContain('[Security.AccessControl.FileSecurity]::new()')
+    expect(start.run).toContain('$security.SetAccessRuleProtection($true, $false)')
+    expect(start.run).toContain('[void]$security.AddAccessRule($accessRule)')
     expect(start.run).toContain('$acl.AreAccessRulesProtected')
     expect(start.run).toContain('Fixture ACL trustee closure changed')
     expect(start.run).toContain('@($systemSid, $administratorsSid)')
@@ -215,6 +217,9 @@ describe('SSH relay runtime artifact workflow', () => {
     expect(stop.run).not.toContain('service-backup.json')
     expect(stop.run).not.toContain('sc.exe config')
     expect(stop.run).toContain('sc.exe delete')
+    expect(stop.run).toContain('Remove-CimInstance -InputObject $profile')
+    expect(stop.run).toContain('Fixture profile did not settle within 10 seconds')
+    expect(stop.run).toContain('fixture profile directory remains')
     expect(stop.run).toContain('Remove-LocalUser')
   })
 
diff --git a/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist-summary.md b/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist-summary.md
index 33674095589..3cb25f2833a 100644
--- a/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist-summary.md
+++ b/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist-summary.md
@@ -9,8 +9,8 @@ keeps commands, hashes, runner identities, timings, and failure details.
 A checked box means the work has evidence in the detailed ledger. Design approval alone does not
 complete a box.
 
-Active checkpoint: **Milestone 6 / Work Package 5 bounded runtime transfer — bounded official
-Windows OpenSSH fixture correction, 2026-07-15, Codex implementation owner.**
+Active checkpoint: **Milestone 6 / Work Package 5 bounded runtime transfer — exact-head Windows
+OpenSSH live-proof diagnosis and fixture correction, 2026-07-15, Codex implementation owner.**
 `E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-PORTABLE-FIXTURE-LOCAL-001` records the portable-fixture
 correction locally green: the no-Orca-publication workflow oracle permits the one exact pinned
 Microsoft fixture release URL while Orca release URLs, `gh release`, and `contents: write` remain
@@ -50,7 +50,24 @@ SID, assert the exact allowed SID closure, and rerun.
 correction locally green: protected allow-only ACLs remove the creator and require exact trustee SID
 closure; 10/10 focused workflow cases, all three PowerShell blocks, 283/283 artifact contracts,
 typecheck, full lint/reliability/max-lines, format, diff, and protected-resolver isolation pass. Push
-for fresh exact-head x64/arm64 proof.
+for fresh exact-head x64/arm64 proof. Exact head
+`d28552f0d953e40d96a4c24cdcdb5ba7d85b7c9f` is pushed; artifact run `29541119819` is RED after
+independently proving all archive/hash/closure/signer/build/cache gates. Windows x64 job
+`87763404467` starts OpenSSH 10.0p2, proves PowerShell 5.1 and pinned-key authentication, then the
+production system-SSH connection probe times out before transfer metrics; teardown also detects a
+loaded fixture profile instead of silently leaving it. Windows ARM64 job `87763404492` stops earlier
+at the exact ACL oracle because the C: fixture root retains explicit Authenticated Users and Users
+ACEs in addition to the intended SYSTEM, Administrators, and fixture-user closure; ownership-safe
+teardown passes. Diagnose and correct both fixture-exposed contracts, preserving connection reuse
+and bounded deterministic teardown, then require fresh exact-head x64/arm64 proof.
+`E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-EXACT-HEAD-CORRECTION-LOCAL-001` records the three bounded
+corrections locally green: the no-input production probe closes native OpenSSH stdin, fixture DACLs
+are atomically replaced with exact protected allow-only rules independent of drive defaults, and an
+owned `Win32_UserProfile` is deleted through a bounded native lifecycle before account/filesystem
+teardown. Focused tests pass 71 cases with one declared live skip, all three PowerShell blocks parse,
+all 283 artifact contracts pass, typecheck and full lint/reliability/max-lines pass, formatting/diff
+are clean, and the protected resolver files remain unchanged. Commit/push this isolated package and
+require fresh x64/arm64 live proof before advancing.
 `E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-AUDIT-001` fixes the loopback-only official Microsoft
 server, fixture-owned non-admin account/ACL, exact host-key trust, Windows PowerShell 5.1,
 serial/default and four-channel metrics, cancellation/collision/cleanup, and deterministic teardown
diff --git a/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist.md b/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist.md
index b381fe1b99d..16d1c3936a4 100644
--- a/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist.md
+++ b/docs/reference/plans/2026-07-14-ssh-relay-github-release-implementation-checklist.md
@@ -8,8 +8,8 @@ work; keep exact commands, runner identities, hashes, metrics, and residual gaps
 
 Date created: 2026-07-14<br>
 Last updated: 2026-07-15<br>
-Current phase: Milestone 6 / Work Package 5 bounded runtime transfer — **In progress — 2026-07-15, Codex implementation owner: bounded official Windows OpenSSH fixture correction**. Keep every capability disconnected from every production/default SSH path. Real Apple/SignPath rehearsals remain an explicit late gate and are not on this package's critical path.<br>
-Session checkpoint: **PORTABLE HOST-KEY ACL CORRECTION LOCALLY GREEN / EXACT-HEAD PROOF NEXT — 2026-07-15, Codex implementation owner** — exact pushed head `130d57d951b5e5cfb0e1e21183ce116684924e2b`, artifact run `29540409361`, and x64/arm64 jobs `87761260157`/`87761260166` pass checkout/toolchain, 283 contracts, clean-build equality/smoke, full-size cache, both pinned archive/library hashes, exact 15-file closure, and every audited common-name/thumbprint check before independently exposing the same narrower RED. Portable OpenSSH rejects the generated host key because `icacls /grant:r` leaves each key creator's explicit runner-account ACE; both service starts fail and both ownership-safe teardowns pass. `E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-PORTABLE-ACL-CORRECTION-LOCAL-001` removes the known creator SID from every protected fixture ACL, asserts protected/allow-only exact trustee SID closure before service start, and passes focused, PowerShell syntax, 283 artifact-contract, typecheck, lint/reliability/max-lines, format, diff, and isolation gates. Commit/push and obtain fresh x64/arm64 proof. Production runtime bytes still cross authenticated SSH and no product remote downloads anything. Do not connect a product caller, change legacy upload/fallback/default behavior, enable a tuple, publish an artifact, or perform SignPath work. Merging to `main` remains prohibited, SignPath is deferred, and legacy remains the production default.<br>
+Current phase: Milestone 6 / Work Package 5 bounded runtime transfer — **In progress — 2026-07-15, Codex implementation owner: exact-head Windows OpenSSH live-proof diagnosis and fixture correction**. Keep every capability disconnected from every production/default SSH path. Real Apple/SignPath rehearsals remain an explicit late gate and are not on this package's critical path.<br>
+Session checkpoint: **WINDOWS ACL/PROBE/PROFILE CORRECTION LOCALLY GREEN / EXACT-HEAD PROOF NEXT — 2026-07-15, Codex implementation owner** — exact pushed head `d28552f0d953e40d96a4c24cdcdb5ba7d85b7c9f`, artifact run `29541119819`, and x64/arm64 jobs `87763404467`/`87763404492` independently pass checkout/toolchain, 283 contracts, clean-build equality/smoke, full-size cache, both pinned archive/library hashes, exact 15-file closure, and every audited signer check before exposing three narrower gaps. ARM64's C: fixture root retains explicit Authenticated Users and Users ACEs; x64's no-input production `ssh.exe` probe leaves piped stdin open and waits 30 seconds after the remote command closes; x64 teardown finds the owned profile's loaded `UsrClass.dat`. `E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-EXACT-HEAD-CORRECTION-LOCAL-001` atomically replaces each fixture DACL with exact protected allow-only rules, closes stdin for the no-input production probe without disabling connection reuse, and deletes the owned `Win32_UserProfile` through a bounded native lifecycle before account/filesystem cleanup. Focused, PowerShell syntax, 283-contract, typecheck, full lint/reliability/max-lines, formatting, diff, and protected-resolver isolation gates pass locally. Commit/push and require fresh x64/arm64 live proof. Production runtime bytes still cross authenticated SSH and no product remote downloads anything. Do not connect a product caller, change legacy upload/fallback/default behavior, enable a tuple, publish an artifact, or perform SignPath work. Merging to `main` remains prohibited, SignPath is deferred, and legacy remains the production default.<br>
 Primary design: [SSH relay GitHub Release plan](./2026-07-14-ssh-relay-github-release-plan.html)<br>
 Motivating issues: [#8450](https://github.com/stablyai/orca/issues/8450), [#1693](https://github.com/stablyai/orca/issues/1693)
 
@@ -19016,6 +19016,82 @@ config/vitest.config.ts --maxWorkers=1 --reporter=dot config/scripts/ssh-relay-r
   remains the sole production/default path; product/Beta/settings/fallback/tuple/publication/signing
   remain absent.
 
+### E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-EXACT-HEAD-CI-RED-001 — native proof exposes ACL replacement, reuse-handshake, and profile-lifecycle gaps
+
+- Date/owner/source: 2026-07-15, Codex implementation owner; exact pushed head
+  `d28552f0d953e40d96a4c24cdcdb5ba7d85b7c9f`, artifact run `29541119819`, native x64 job
+  `87763404467` (`windows-2022`, Windows Server 2022 build 20348) and native ARM64 job
+  `87763404492` (`windows-11-arm`).
+- Shared green boundary: both jobs pass exact checkout/toolchain, all 283 runtime artifact contracts,
+  clean-build equality/smoke, full-size client extraction/cache measurement, both exact portable
+  archive and `libcrypto.dll` hashes, exact 15-file closure, and every audited Authenticode common
+  name/thumbprint check. This preserves all earlier build/trust evidence.
+- ARM64 RED: fixture download and extraction pass, then the pre-service exact ACL oracle rejects the
+  fixture root. Its protected allow-only trustee set is `S-1-5-11`, `S-1-5-18`, fixture user
+  `S-1-5-21-1882319117-3219095328-2125279949-1001`, `S-1-5-32-544`, and `S-1-5-32-545`.
+  Authenticated Users and Users are undeclared explicit entries inherited from that runner volume's
+  creation defaults; removing only the creator SID cannot establish exact closure. The service and
+  transfer never start, and the ownership-safe teardown passes.
+- X64 RED: the same ACL oracle passes, the official server starts as
+  `OpenSSH_for_Windows_10.0p2 Win32-OpenSSH-GitHub, LibreSSL 4.2.0`, Windows PowerShell is
+  `5.1.20348.4294`, exact host-key trust and fixture-user public-key authentication pass. The
+  full-size suite then fails after roughly 30 seconds at `src/main/ssh/ssh-connection.ts:750` with
+  `System SSH connection timed out`, before serial transfer metrics. Server logs show an
+  authenticated session closing/read error plus a later pre-auth reset. Preserve
+  `systemSshConnectionReuse: true`; connection reuse is a required contract, not a fixture option to
+  disable.
+- X64 teardown RED: service/account cleanup runs, but direct recursive deletion rejects
+  `C:\Users\orca_ssh_fixture\AppData\Local\Microsoft\Windows\UsrClass.dat` because the profile is
+  still loaded. This is a deterministic fixture lifecycle gap. Do not ignore the locked profile or
+  weaken teardown; unload/remove it through a bounded native profile lifecycle and retain exact
+  absence assertions.
+- Correction gate: replace each fixture DACL with the exact declared allow-only SID set independent
+  of volume defaults; isolate and prove the production system-SSH reuse handshake against Windows
+  OpenSSH; unload/remove the owned fixture profile boundedly before filesystem deletion. Update the
+  workflow oracle, parse all PowerShell blocks, rerun focused and 283-contract/static/isolation
+  gates, then require fresh exact-head x64/arm64 service/auth/full-size/cancellation/collision/reuse/
+  teardown proof. Legacy remains the sole production/default path and SignPath remains deferred.
+
+### E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-EXACT-HEAD-CORRECTION-LOCAL-001 — exact DACL, no-input probe, and owned-profile lifecycle are locally green
+
+- Date/owner/base/runner: 2026-07-15, Codex implementation owner; uncommitted correction atop exact
+  RED head `d28552f0d953e40d96a4c24cdcdb5ba7d85b7c9f` on Apple arm64, macOS 26.2 build 25C56,
+  Node 26.5.0, pnpm 10.24.0. Native Windows execution remains required.
+- Correction: the production system-SSH connection probe now closes its no-input child stdin after
+  installing listeners. This lets native Windows `ssh.exe` settle after the remote echo closes and
+  changes no authentication, command, RPC, retry, fallback, or mux policy. The live fixture creates
+  a fresh `DirectorySecurity` or `FileSecurity` DACL and atomically installs only the declared
+  SYSTEM, Administrators, and optional fixture-user allow rules, so C:/D: defaults cannot survive.
+  Teardown uses the owned account SID to retry `Remove-CimInstance` for `Win32_UserProfile` for at
+  most ten seconds before account and directory deletion, retaining exact absence assertions.
+- Focused command: `/usr/bin/time -l pnpm exec vitest run --config config/vitest.config.ts
+--maxWorkers=1 src/main/ssh/ssh-connection.test.ts
+src/main/ssh/ssh-relay-runtime-windows-system-ssh-openssh-full-size.test.ts
+config/scripts/ssh-relay-runtime-workflow.test.mjs` passes 71/71 cases with the one declared native
+  live skip in 3.83 seconds real; maximum RSS is 162,643,968 bytes and peak footprint is 98,490,224
+  bytes. Independent YAML extraction plus PowerShell `[scriptblock]::Create()` parses all three
+  start/measure/stop blocks.
+- Release-contract command: `/usr/bin/time -l pnpm exec vitest run --config
+config/vitest.config.ts --maxWorkers=1 --reporter=dot
+config/scripts/ssh-relay-runtime-*.test.mjs` passes 50 files and 283/283 cases in 83.86 seconds
+  real; maximum RSS is 195,739,648 bytes and peak footprint is 97,408,952 bytes.
+- Static evidence: `/usr/bin/time -l pnpm typecheck` passes in 30.12 seconds real; maximum RSS is
+  1,253,359,616 bytes and peak footprint is 97,130,256 bytes. The first full-lint attempt honestly
+  rejected the workflow oracle at 601 lines; one redundant `Get-CimInstance` string assertion was
+  removed while the `Remove-CimInstance`, bounded timeout, exact profile-directory, and runtime
+  behavior assertions remain. The rerun `/usr/bin/time -l pnpm lint` passes in 73.17 seconds real
+  with only the 26 pre-existing warnings, all 41 reliability gates, the 355-entry max-lines ratchet,
+  localization, and bundled-guide checks; maximum RSS is 2,072,281,088 bytes and peak footprint is
+  98,244,440 bytes.
+- Isolation evidence: targeted `oxfmt --check`, `git diff --check`, and exact protected-file equality
+  against the base head pass. Only the artifact workflow/oracle, system-SSH connection/probe test,
+  and three planning artifacts are modified; the protected resolver files remain unchanged.
+- Residual boundary: local macOS proof cannot execute Windows DACL replacement, native `ssh.exe`
+  stdin settlement, `Win32_UserProfile` deletion, service/auth, PowerShell 5.1, full-size transfer,
+  cancellation, collision, or teardown. Commit/push this isolated correction and require fresh
+  exact-head x64/arm64 proof before closing the live Windows gate. Legacy remains the sole
+  production/default path; product/Beta/settings/fallback/tuple/publication/signing remain absent.
+
 ## Accepted Gaps
 
 No product gap is accepted merely because it appears in this list. Each entry requires explicit
@@ -19074,12 +19150,13 @@ The project is not complete until every applicable item below is checked with ev
 
 ## Next Required Action
 
-Commit and push the locally green role-based fixture trust correction in
-`E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-LIBCRYPTO-CORRECTION-LOCAL-001`, then require fresh exact-head
-x64/arm64 archive/native-closure/signature, ACL, PowerShell 5.1, exact full-size serial/four-channel/
-cancellation, collision, connection-reuse, and teardown evidence. Do not check the broad Milestone
-6 Windows system-SSH item yet. Do not add an Electron/startup/product importer, per-target mode
-wiring, fallback, tuple enablement, release publication, or default behavior.
+Commit and push the locally green isolated correction in
+`E-M6-WINDOWS-SYSTEM-SSH-TREE-LIVE-EXACT-HEAD-CORRECTION-LOCAL-001`, then require fresh exact-head
+x64/arm64 archive/native-closure/signature, ACL, PowerShell 5.1, exact
+full-size serial/four-channel/cancellation, collision, connection-reuse, and teardown evidence. Do
+not check the broad Milestone 6 Windows system-SSH item yet. Do not add an Electron/startup/product
+importer, per-target mode wiring, fallback, tuple enablement, release publication, or default
+behavior.
 Keep Node upstream `.tar.xz` inputs, Windows ZIP, `ORCA_RELAY_PATH`, existing desktop required-assets
 behavior, detached-signature byte encoding, Windows arm64 build 26100, macOS 13.5, Linux kernel 4.18,
 release-cut, desktop builds, publication, and every tuple separately gated.
diff --git a/docs/reference/plans/2026-07-14-ssh-relay-github-release-plan.html b/docs/reference/plans/2026-07-14-ssh-relay-github-release-plan.html
index 7bcff37f4e0..39e6db19cf1 100644
--- a/docs/reference/plans/2026-07-14-ssh-relay-github-release-plan.html
+++ b/docs/reference/plans/2026-07-14-ssh-relay-github-release-plan.html
@@ -1642,7 +1642,8 @@
                   <td>
                     Full-size runtime over SFTP and POSIX/Windows system SSH; tar/no-tar; no remote
                     hash tools; corrupted upload; bundled-Node corruption/failure; bounded memory
-                    and concurrency; <code>MaxSessions=1</code>; interrupted upload; stale lock
+                    and concurrency; no-input system-SSH probe stdin/child settlement;
+                    <code>MaxSessions=1</code>; interrupted upload; stale lock
                   </td>
                   <td>
                     Bundled Node hashes the full staged tree before sentinel write;
@@ -1666,9 +1667,11 @@
                   <td>
                     This trust exception provisions only the loopback CI server. Production clients
                     and SSH hosts perform no fixture download. Fixture host-key and authorized-key
-                    ACL creation removes creator-specific access and asserts the exact allowed SID
-                    closure before service start; none of this weakens runtime artifact,
-                    native-signing, transfer, install, or launch trust.
+                    ACL creation replaces volume-specific defaults with the exact allowed,
+                    protected, allow-only SID closure before service start. Owned fixture profiles
+                    are unloaded and removed through a bounded native lifecycle before exact
+                    teardown assertions; none of this weakens runtime artifact, native-signing,
+                    transfer, install, or launch trust.
                   </td>
                 </tr>
                 <tr>
diff --git a/src/main/ssh/ssh-connection.test.ts b/src/main/ssh/ssh-connection.test.ts
index 90807615000..b0c9194d992 100644
--- a/src/main/ssh/ssh-connection.test.ts
+++ b/src/main/ssh/ssh-connection.test.ts
@@ -932,6 +932,11 @@ describe('SshConnection', () => {
 
   it('uses system SSH transport when ProxyUseFdpass is resolved by OpenSSH', async () => {
     vi.mocked(resolveWithSshG).mockResolvedValueOnce(createResolvedConfig())
+    let probeChannel: ReturnType<typeof createSystemCommandChannel> | undefined
+    spawnSystemSshCommandMock.mockImplementationOnce(() => {
+      probeChannel = createSystemCommandChannel()
+      return probeChannel
+    })
     const conn = new SshConnection(createTarget({ configHost: 'fdpass-host' }), createCallbacks())
 
     await conn.connect()
@@ -947,6 +952,7 @@ describe('SshConnection', () => {
         resolvedConfig: expect.objectContaining({ proxyUseFdpass: true })
       }
     )
+    expect(probeChannel?.stdin.end).toHaveBeenCalledOnce()
   })
 
   it('allows concurrent exec commands for system SSH with an Orca ControlMaster socket', async () => {
diff --git a/src/main/ssh/ssh-connection.ts b/src/main/ssh/ssh-connection.ts
index a1e55027080..a8f11275c0b 100644
--- a/src/main/ssh/ssh-connection.ts
+++ b/src/main/ssh/ssh-connection.ts
@@ -755,6 +755,9 @@ export class SshConnection {
         channel.stderr.on('data', onStderrData)
         channel.on('error', onError)
         channel.on('close', onClose)
+        // Why: native Windows OpenSSH keeps its input worker alive while the
+        // pipe is open, even though this probe can never consume stdin.
+        ;(channel as ClientChannel & { stdin: NodeJS.WritableStream }).stdin.end()
       })
     } catch (err) {
       this.useSystemSshTransport = false