diff --git a/config/reliability-gates.jsonc b/config/reliability-gates.jsonc
index d9789cb0ab3..ebb7c20b9a1 100644
--- a/config/reliability-gates.jsonc
+++ b/config/reliability-gates.jsonc
@@ -20,7 +20,7 @@
       "surfaces": ["queued terminal startup commands", "zsh, bash, and Fish startup output"],
       "platforms": ["macos", "linux"],
       "providers": ["local", "local-daemon", "ssh-daemon", "ssh-relay", "paired-runtime"],
-      "coveredPlatforms": ["macos"],
+      "coveredPlatforms": ["macos", "linux"],
       "coveredProviders": ["local", "local-daemon", "ssh-relay"],
       "coverageNotes": "Real macOS node-pty integration covers zsh 5.9 .zshenv/.zprofile and bash 3.2 profile replacement shells, including exec -a names, same-shell and child-process silent reads, a blocking zle-line-init hook, non-shell readline replacements, and a non-shell image renamed zsh. A real Fish PTY proves marker stripping is byte-exact and does not render bracketed-paste control text. An Ubuntu 20.04 container confirms compatible zsh/bash termios. Deterministic owner contracts cover local, daemon, and SSH relay identity/readiness composition plus provider- and renderer-owned delivery. Renderer-owned relay fallback publishes the existing ready marker, so mixed client/host versions need no new wire capability. Live SSH, paired-runtime, and WSL remain gaps.",
       "motivatingLinks": [
@@ -31,7 +31,8 @@
       "oracle": "Split Fish output immediately after the ready marker and after the following ESC introducer; local and daemon owners must emit the exact ESC [ ? 2004 h bytes and headless xterm must not render literal control text. Run the real generated wrappers under node-pty with disposable zsh, bash, and Fish startup files. Plain and exec -a replacement shells must receive one queued command at their first completed line editor without waiting for the 15-second timeout. The identical oracle must time out without the startup identity and prompt fallback. Same-shell reads, child-process reads, a blocking zle-line-init hook, sqlite3, and sqlite3 renamed zsh must not trigger prompt fallback. Relay owner coverage must use the same lossless scanner composition and release through the same prompt contract.",
       "commands": [
         "pnpm exec vitest run --config config/vitest.config.ts src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts src/main/line-editor-ready-output-scanner.test.ts src/main/shell-startup-identity-scanner.test.ts src/main/shell-startup-output-scanner.test.ts src/main/shell-prompt-readiness-probe.test.ts src/shared/pty-slave-line-discipline-echo.test.ts src/shared/shell-process-readiness.test.ts src/main/daemon/session.test.ts src/main/daemon/shell-ready.test.ts src/main/providers/local-pty-shell-ready.test.ts src/main/providers/local-pty-provider.test.ts src/relay/pty-shell-launch.test.ts src/relay/pty-handler.test.ts",
-        "pnpm exec vitest run --config config/vitest.config.ts src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts src/relay/pty-handler.test.ts"
+        "pnpm exec vitest run --config config/vitest.config.ts src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts src/relay/pty-handler.test.ts",
+        "pnpm exec vitest run --config config/vitest.config.ts --maxWorkers=1 src/main/daemon/shell-ready.test.ts src/main/shell-startup-output-scanner.test.ts"
       ],
       "testFiles": [
         "src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts",
@@ -89,11 +90,20 @@
         }
       ],
       "evidenceRuns": [
+        {
+          "date": "2026-08-12",
+          "runner": "manual",
+          "platform": "linux",
+          "command": "pnpm exec vitest run --config config/vitest.config.ts --maxWorkers=1 src/main/daemon/shell-ready.test.ts src/main/shell-startup-output-scanner.test.ts",
+          "result": "passed",
+          "durationSeconds": 7,
+          "summary": "A clean Debian 12 arm64 container with real Fish 3.6 and node-pty passed exact marker-stripped output plus headless-xterm rendering."
+        },
         {
           "date": "2026-08-12",
           "runner": "local",
           "platform": "macos",
-          "command": "pnpm exec vitest run --config config/vitest.config.ts src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts src/main/line-editor-ready-output-scanner.test.ts src/main/shell-startup-identity-scanner.test.ts src/main/shell-prompt-readiness-probe.test.ts src/shared/pty-slave-line-discipline-echo.test.ts src/shared/shell-process-readiness.test.ts src/main/daemon/session.test.ts src/main/daemon/shell-ready.test.ts src/main/providers/local-pty-shell-ready.test.ts src/main/providers/local-pty-provider.test.ts src/relay/pty-shell-launch.test.ts src/relay/pty-handler.test.ts",
+          "command": "pnpm exec vitest run --config config/vitest.config.ts src/main/daemon/repro-13767-shell-ready-marker-lost-to-exec.test.ts src/main/line-editor-ready-output-scanner.test.ts src/main/shell-startup-identity-scanner.test.ts src/main/shell-startup-output-scanner.test.ts src/main/shell-prompt-readiness-probe.test.ts src/shared/pty-slave-line-discipline-echo.test.ts src/shared/shell-process-readiness.test.ts src/main/daemon/session.test.ts src/main/daemon/shell-ready.test.ts src/main/providers/local-pty-shell-ready.test.ts src/main/providers/local-pty-provider.test.ts src/relay/pty-shell-launch.test.ts src/relay/pty-handler.test.ts",
           "result": "passed",
           "durationSeconds": 4,
           "summary": "All real exec, silent-read, line-init-hook, renamed-image, disabled-bracketed-paste, and relay-owner oracles plus identity, foreground, executable-image, protocol, and line-editor contracts passed."
@@ -109,7 +119,7 @@
       },
       "redGreenEvidence": {
         "status": "complete",
-        "evidence": "Oracle SHA-256 b13b08006a38b2adc2acb51ae9342909514e55ab4822fac4fbb76cd49b344cc6 is byte-identical across runs. Latest main 09ec516ae5 and the candidate with its production implementation reverted both failed exactly the three zsh .zprofile/.zshenv and bash exec cases by deterministic 5-second timeout; the zle-line-init oracle also exposed unsafe baseline delivery, while all ten other safety controls passed. The candidate passed all 14 on macOS."
+        "evidence": "The Fish chunk oracle patch SHA-256 fd49a4d3d91bd5f0d10c1b1f44f4cfbd92cef9155a5505b415c8680184cdc765 is byte-identical across runs. Scan target e4c278eb52, latest main d9b390f4fd, and candidate 1f9715c87b with the fix commit reverted each failed the ESC-introducer split in both local and daemon owners while passing both marker-only splits. Candidate 1f9715c87b passed all four cases plus the independent headless-xterm render oracle. The original exec-readiness oracle SHA-256 b13b08006a38b2adc2acb51ae9342909514e55ab4822fac4fbb76cd49b344cc6 remains 14/14 green."
       },
       "performanceBudget": {
         "required": true,
diff --git a/src/main/shell-startup-output-scanner.test.ts b/src/main/shell-startup-output-scanner.test.ts
index ee3530ec386..b4ace12a456 100644
--- a/src/main/shell-startup-output-scanner.test.ts
+++ b/src/main/shell-startup-output-scanner.test.ts
@@ -37,6 +37,17 @@ describe('shell startup output scanner', () => {
     })
   })
 
+  it('counts an identity-held byte as post-marker output', () => {
+    const state = createShellStartupOutputScanState()
+
+    expect(scanShellStartupOutput(state, `${READY_MARKER}\x1b`)).toEqual({
+      output: '\x1b',
+      shellPid: null,
+      ready: true,
+      postMarkerBytesObserved: true
+    })
+  })
+
   it('drains every incomplete scanner prefix in byte order', () => {
     const state = createShellStartupOutputScanState()
     expect(scanShellStartupOutput(state, '\x1b]777;orca-shell-st').output).toBe('')
diff --git a/src/main/shell-startup-output-scanner.ts b/src/main/shell-startup-output-scanner.ts
index 4a9d5f90e87..99606f6d047 100644
--- a/src/main/shell-startup-output-scanner.ts
+++ b/src/main/shell-startup-output-scanner.ts
@@ -46,15 +46,18 @@ export function scanShellStartupOutput(
 
   const readiness = scanForShellReady(state.ready, data)
   let output = readiness.output
+  let postMarkerBytesObserved = readiness.postMarkerBytesObserved
   if (readiness.matched && state.identity) {
-    output += drainShellStartupIdentityHeldBytes(state.identity)
+    const heldOutput = drainShellStartupIdentityHeldBytes(state.identity)
+    output += heldOutput
+    postMarkerBytesObserved ||= heldOutput.length > 0
     state.identity = null
   }
   return {
     output,
     shellPid,
     ready: readiness.matched,
-    postMarkerBytesObserved: readiness.postMarkerBytesObserved
+    postMarkerBytesObserved
   }
 }