diff --git a/smoke.sh b/smoke.sh
index 498b4c2..c582d4c 100755
--- a/smoke.sh
+++ b/smoke.sh
@@ -105,8 +105,28 @@ fi
 # --- compose the smoke tab data URL ---
 read -r -d '' SMOKE_HTML <<'EOF' || true
 <title>Mokosh Smoke Test</title>
-<style>body{font-family:sans-serif;background:#222;color:#eee;padding:40px;line-height:1.5}code{background:#444;padding:2px 6px;border-radius:3px}ol li{margin:6px 0}.flash{animation:flash 1s infinite;background:#0a4;padding:4px 8px;display:inline-block}@keyframes flash{0%,100%{opacity:1}50%{opacity:.4}}</style>
+<style>
+body{font-family:sans-serif;background:#222;color:#eee;padding:40px;line-height:1.5}
+code{background:#444;padding:2px 6px;border-radius:3px}
+ol li{margin:6px 0}
+.flash{animation:flash 1s infinite;background:#0a4;padding:4px 8px;display:inline-block}
+@keyframes flash{0%,100%{opacity:1}50%{opacity:.4}}
+/* Diagnostic timer overlay — high-contrast monospace pinned top-right so it appears in every
+   recorded frame. T+ counts seconds since page load (matches the moment Mokosh starts recording);
+   wall is HH:MM:SS local time for cross-referencing with SW console logs. The visible value
+   in the last frame of the saved video minus the value at save-click time = the operator-visible
+   "stale gap" the D-13 architecture leaks. */
+#mokosh-timer{position:fixed;top:12px;right:12px;background:#000;color:#0f0;padding:10px 16px;
+  border:2px solid #0f0;border-radius:6px;font-family:'Courier New',monospace;font-size:28px;
+  font-weight:bold;line-height:1.15;text-align:right;z-index:9999;box-shadow:0 2px 8px rgba(0,0,0,.6)}
+#mokosh-timer .lbl{font-size:11px;color:#0a0;letter-spacing:.05em}
+#mokosh-timer .val{font-variant-numeric:tabular-nums}
+</style>
 <body>
+<div id="mokosh-timer">
+  <div><span class="lbl">T+</span> <span class="val" id="t-elapsed">0.0s</span></div>
+  <div><span class="lbl">wall</span> <span class="val" id="t-wall">--:--:--</span></div>
+</div>
 <h1>🧵 Mokosh Smoke Test</h1>
 <p>This tab is the share-screen target. The picker auto-accepts because the title matches <code>--auto-select-desktop-capture-source</code>.</p>
 <h2>Steps:</h2>
@@ -114,10 +134,26 @@ read -r -d '' SMOKE_HTML <<'EOF' || true
 <li><strong class="flash">First time only:</strong> Go to <code>chrome://extensions</code> → toggle <strong>Developer mode</strong> ON → <strong>Load unpacked</strong> → select <code>/home/parf/projects/work/repremium/dist</code>.<br>(Set <code>KEEP_PROFILE=1</code> when re-running this script to skip the reload.)</li>
 <li>Click the <strong>AI Call Recorder</strong> toolbar icon (or puzzle-piece menu).</li>
 <li>The picker auto-accepts <em>this tab</em>. Confirm Chrome's "Sharing your screen" indicator appears.</li>
-<li>Wait <strong>≥ 35 seconds</strong>. Move the mouse around or scroll this page so vp9 has frame deltas.</li>
-<li>Click the toolbar icon again → click <strong>Сохранить отчёт об ошибке</strong>.</li>
+<li>Wait <strong>≥ 35 seconds</strong>. <em>Note the timer value in the corner</em>. Move the mouse around or scroll this page so vp9 has frame deltas.</li>
+<li>Click the toolbar icon again → click <strong>Сохранить отчёт об ошибке</strong>. <em>Note T+ and wall at the moment you click — compare to the LAST visible timer values in the saved video. Gap = operator-visible "stale" window.</em></li>
 </ol>
 <p>The script in your terminal will detect the download and finish the ffprobe gate automatically.</p>
+<script>
+(function(){
+  var t0 = performance.now();
+  var el = document.getElementById('t-elapsed');
+  var wallEl = document.getElementById('t-wall');
+  function pad(n){return String(n).padStart(2,'0');}
+  function tick(){
+    var dt = (performance.now() - t0) / 1000;
+    el.textContent = dt.toFixed(1) + 's';
+    var now = new Date();
+    wallEl.textContent = pad(now.getHours()) + ':' + pad(now.getMinutes()) + ':' + pad(now.getSeconds());
+  }
+  tick();
+  setInterval(tick, 100);
+})();
+</script>
 </body>
 EOF
 # WR-04 fix: python3 is required (asserted in pre-flight). NO fallback —
