diff --git a/.github/workflows/ssh-relay-runtime-artifacts.yml b/.github/workflows/ssh-relay-runtime-artifacts.yml
index 6287cd1da6c..4e4aecb241a 100644
--- a/.github/workflows/ssh-relay-runtime-artifacts.yml
+++ b/.github/workflows/ssh-relay-runtime-artifacts.yml
@@ -573,6 +573,10 @@ jobs:
           cp "$fixture/client-key.pub" "$HOME/.ssh/authorized_keys"
           chmod 600 "$HOME/.ssh/authorized_keys" "$fixture/client-key" "$fixture/host-key"
           sudo chown root:root "$fixture/host-key"
+          # Why: hosted runner accounts are shadow-locked, which sshd rejects before public-key auth.
+          random_password=$(openssl rand -hex 32)
+          sudo usermod --password "$(openssl passwd -6 "$random_password")" "$USER"
+          unset random_password
           port=22222
           server_version=$(/usr/sbin/sshd -V 2>&1 | head -1)
           config="$fixture/sshd_config"
@@ -599,7 +603,7 @@ jobs:
               break
             fi
             if test "$attempt" = 20; then
-              cat "$fixture/sshd.log"
+              sudo tail -200 "$fixture/sshd.log"
               exit 1
             fi
             sleep 0.25
diff --git a/config/scripts/ssh-relay-runtime-workflow.test.mjs b/config/scripts/ssh-relay-runtime-workflow.test.mjs
index 97bf9a9a7aa..427b5e93b42 100644
--- a/config/scripts/ssh-relay-runtime-workflow.test.mjs
+++ b/config/scripts/ssh-relay-runtime-workflow.test.mjs
@@ -95,6 +95,8 @@ describe('SSH relay runtime artifact workflow', () => {
     expect(start.if).toBe("runner.os == 'Linux'")
     expect(start.run).toContain('ListenAddress 127.0.0.1')
     expect(start.run).toContain('Subsystem sftp internal-sftp')
+    expect(start.run).toContain('sudo usermod --password')
+    expect(start.run).toContain('PasswordAuthentication no')
     expect(start.run).toContain('timeout --signal=TERM --kill-after=15s 180s sudo apt-get')
     expect(measure.if).toBe("runner.os == 'Linux'")
     expect(measure.run).toContain('ssh-relay-runtime-sftp-openssh-full-size.test.ts')
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 1f38d7ffc10..f8475922b92 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
@@ -10,7 +10,12 @@ A checked box means the work has evidence in the detailed ledger. Design approva
 complete a box.
 
 Active checkpoint: **Milestone 6 / Work Package 5 bounded runtime transfer — disconnected live
-OpenSSH SFTP composition is in progress, 2026-07-15, Codex implementation owner.**
+OpenSSH SFTP runner fixture auth correction is in progress, 2026-07-15, Codex implementation owner.**
+`E-M6-SFTP-LIVE-COMPOSITION-CI-RED-001` records both target-native Linux jobs passing build,
+contracts, and existing full-size measurement before stock sshd rejected GitHub's shadow-locked
+`runner` account ahead of public-key validation. No SFTP bytes were sent and no live cell is credited.
+The narrow rerun keeps password authentication disabled and gives only the ephemeral account a fresh
+random password hash so public-key authentication can proceed.
 `E-M6-SFTP-LIVE-COMPOSITION-AUDIT-001` limits this package to one authenticated built-in
 `SshConnection`, one raw SFTP channel, the existing one-to-four file transfer, captured-transport-
 only force close with awaited teardown, and exact full-size Linux x64/arm64 runtime transfer against
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 8df452fb05e..0228bafd963 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
@@ -9,7 +9,7 @@ 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: disconnected authenticated-connection/SFTP-tree composition and live OpenSSH proof**. 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: **LIVE SFTP COMPOSITION LOCALLY GREEN / EXACT-HEAD RUNNER PROOF NEXT — 2026-07-15, Codex implementation owner** — `E-M6-SFTP-LIVE-COMPOSITION-LOCAL-001` proves the disconnected authenticated-connection owner, captured-client force close, cancellation cleanup/breaker ordering, workflow oracle, focused/broad/release suites, typecheck, full lint, formatting, max-lines, diff, protected-resolver, and no-product-import gates locally. The purpose suite is 15/15; the live full-size suite is deliberately skipped locally because no runner OpenSSH/runtime inputs are present and therefore earns no live cell. Push this isolated package and require exact-head Linux x64/arm64 stock-OpenSSH full-size metrics before crediting live SFTP. Do not credit Windows/POSIX system SSH, high-RTT, `MaxSessions=1`, product/settings/fallback wiring, tuple enablement, publication, or default behavior. Merging to `main` remains prohibited, SignPath is deferred, and legacy remains the production default.<br>
+Session checkpoint: **LIVE SFTP RUNNER FIXTURE RED / NARROW AUTH-FIX IN PROGRESS — 2026-07-15, Codex implementation owner** — `E-M6-SFTP-LIVE-COMPOSITION-CI-RED-001` proves both target-native Linux builds and all pre-live contracts passed, then the loopback stock-OpenSSH fixture rejected GitHub's shadow-locked `runner` account before public-key validation. No SFTP bytes were sent and no live cell is credited. Keep password authentication disabled; assign only a fresh random ephemeral password hash so stock sshd accepts the runner account for public-key authentication, fix failure-log readability, rerun exact head, and require full metrics. Do not credit Windows/POSIX system SSH, high-RTT, `MaxSessions=1`, product/settings/fallback wiring, tuple enablement, publication, or default behavior. 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)
 
@@ -17323,6 +17323,32 @@ src/main/ssh/ssh-relay-runtime-sftp-tree-transfer.test.ts` — PASS, 15/15 in 1.
   settings/fallback wiring, tuple enablement, publication, or default behavior is proved. Legacy
   remains the sole production/default path and SignPath remains deferred.
 
+### E-M6-SFTP-LIVE-COMPOSITION-CI-RED-001 — stock sshd rejects the hosted runner's locked account
+
+- Date/owner/head/run: 2026-07-15, Codex implementation owner; exact implementation commit
+  `32f78d720febdb5581282cfbc64b6aae374930f4`, SSH Relay Runtime Artifacts run
+  [29513130758](https://github.com/stablyai/orca/actions/runs/29513130758).
+- Passing boundary before RED: Linux x64 job
+  [87671358587](https://github.com/stablyai/orca/actions/runs/29513130758/job/87671358587) and Linux
+  arm64 job [87671358592](https://github.com/stablyai/orca/actions/runs/29513130758/job/87671358592)
+  both pass checkout, exact Node 24.18.0 setup, native identity, prerequisites, the complete runtime
+  contract suite including all five new connection-owner cases, exact Node input download, target-
+  native build/reproducibility/read-back/smoke, and full-size extraction/cache/scan/stream measurement.
+- Expected evidence failure: both jobs then fail `Start loopback OpenSSH SFTP fixture`; the live
+  transfer step is skipped and sends zero SFTP bytes. The server binds only `127.0.0.1:22222`, but
+  every key-auth probe is rejected with `User runner not allowed because account is locked` before
+  public-key validation. The arm64 cleanup log confirms stock sshd accepted the config/listener and
+  rejected only the shadow account state. The x64 runner is Ubuntu 24.04.4 image
+  `20260714.240.1`, X64, kernel `6.17.0-1020-azure`; arm64 is the target-native hosted counterpart.
+- Narrow correction: retain `PasswordAuthentication no`, `KbdInteractiveAuthentication no`,
+  loopback-only listen, one ephemeral Ed25519 client key, and strict modes. Generate a fresh random
+  32-byte password, store only its SHA-512 shadow hash on the ephemeral runner account, immediately
+  unset the plaintext shell variable, and continue to authenticate only with the generated public
+  key. Also read root-owned sshd logs through `sudo` on failure. This changes only CI fixture account
+  eligibility; no product authentication, connection, transfer, or fallback code changes.
+- Residual: no live SFTP transfer/filesystem/mode/RSS/cancellation evidence is credited from this
+  run. Exact-head Linux x64/arm64 rerun plus all-six/adjacent regression proof remains mandatory.
+
 ## Accepted Gaps
 
 No product gap is accepted merely because it appears in this list. Each entry requires explicit