diff --git a/.planning/debug/sw-offscreen-persistence-investigation-session-2.md b/.planning/debug/sw-offscreen-persistence-investigation-session-2.md
new file mode 100644
index 0000000..fe6a3e2
--- /dev/null
+++ b/.planning/debug/sw-offscreen-persistence-investigation-session-2.md
@@ -0,0 +1,96 @@
+---
+status: diagnosed
+trigger: "Continuation of session-1 (committed at d614462). Prior verdict INCONCLUSIVE; ~75 min cheap disambiguation plan: Step A fix offscreen target filter + re-run + capture logs; Step B segment-count probe pre-kill; Step C spike without worker.close(). Synthesize verdict for SC#1 plan-fix routing."
+created: 2026-05-21T19:30:00Z
+updated: 2026-05-21T20:35:00Z
+parent_session: ".planning/debug/sw-offscreen-persistence-investigation.md (committed d614462)"
+goal: find_root_cause_only
+verdict: REFUTED-architecture (canvas-captureStream issue)
+recommendation: "REFUTE the Plan 04-04 SUMMARY's framing 'spike FAILED → architectural plan-fix needed'. The architecture works correctly; the SPIKE methodology is invalid. ROADMAP SC#1 remains OPEN but the previously-recommended IndexedDB persistence plan-fix would NOT close it (the spike would STILL produce 8505 bytes after IDB persistence is added, because the failure is in the test's fake-stream pipeline, not in the persistence layer). Reframe SC#1 verification methodology BEFORE doing any architectural work."
+---
+
+## Current Focus
+
+verdict: REFUTED-architecture (canvas-captureStream issue)
+confidence: HIGH — three independent spike runs converge on the same conclusion via different observability channels.
+hypothesis_state: "RESOLVED. Root cause was Hypothesis B (canvas-captureStream + headless idle = 0-frame segments). Hypotheses A (architectural RAM loss) and C (CDP-induced offscreen teardown) are REFUTED by empirical evidence below."
+next_action: "Return verdict + recommendation to orchestrator. Plan-fix routing decision: do NOT proceed with IndexedDB persistence plan-fix; instead, propose a Phase 5 plan that reframes SC#1 verification methodology (real getDisplayMedia in non-headless Puppeteer; OR a video-file-backed fake stream that survives headless throttling)."
+
+## Symptoms
+
+(Inherited verbatim from session-1; IMMUTABLE.)
+
+expected: "After 5 min SW idle + SAVE_ARCHIVE, video buffer survives at 1-3 MB."
+actual: "videoSize=8505 bytes (deterministic; 4/4 runs in session-1 + 2/2 runs in session-2 + 1/1 Step-C variant = 7/7 reproducibility)."
+errors: "ffprobe: 'End of file' + 'Duplicate element'; no valid clusters."
+reproduction: "HEADLESS=1 npx tsx tests/uat/spike-a33-sw-persistence.ts (~6 min wall-clock)."
+
+## Eliminated
+
+- hypothesis: "(A) Architectural — offscreen-RAM `segments: Blob[] = []` lost across SW termination"
+  evidence: "Direct observation via the `get-segment-count` bridge probe at 3 checkpoints in the canonical spike: POST-PRIME=0, PRE-KILL=3, POST-KILL=3. Segments structurally survive the SW kill at full count. The offscreen document itself responds to the post-kill probe (segments.length=3), so it did not die with the SW. ALSO: Step C (no SW kill) produces the IDENTICAL 8505-byte result — kill is irrelevant."
+  timestamp: 2026-05-21T19:55:00Z
+
+- hypothesis: "(C) CDP-artifact — Puppeteer worker.close() collaterally tears down offscreen via cross-target side effect (Puppeteer #9995 territory)"
+  evidence: "Step C spike WITHOUT worker.close() produces IDENTICAL 8505-byte videoSize. Removing the SW-kill step does NOT improve the outcome. The CDP attach is not implicated."
+  timestamp: 2026-05-21T20:01:00Z
+
+## Evidence
+
+- timestamp: "2026-05-21T19:30Z"
+  checked: "Existing `__mokoshOffscreenQuery` 'get-segment-count' bridge op at src/test-hooks/offscreen-hooks.ts:493-523"
+  found: "The bridge op already exists. The harness can dispatch chrome.runtime.sendMessage({type: '__mokoshOffscreenQuery', op: 'get-segment-count'}) from the harness page realm, and the offscreen-hooks's onMessage listener responds with {count: number} where count=segmentCountGetter() which is closure over recorder's module-level segments.length. This is a PRODUCTION TEST SURFACE (gated by __MOKOSH_UAT__, in the canonical 12-string FORBIDDEN_HOOK_STRINGS inventory)."
+  implication: "Step B uses this without adding ANY new symbol — zero impact on FORBIDDEN_HOOK_STRINGS count. Probe rides production surface."
+
+- timestamp: "2026-05-21T19:48Z (canonical spike with probes + race-broken offscreen attach)"
+  checked: "HEADLESS=1 npx tsx tests/uat/spike-a33-sw-persistence.ts → /tmp/04-04-debug-step-ab.log"
+  found: "SPIKE PROBE [POST-PRIME]: segments.length=0; SPIKE PROBE [PRE-KILL]: segments.length=3; SPIKE PROBE [POST-KILL]: segments.length=3. Final videoSize=8505 bytes."
+  implication: "Segments accumulated to MAX_SEGMENTS=3 during the 5-min idle (recorder rotation worked). Segments survived the SW kill (count unchanged at 3). YET the final WebM is 8505 bytes (no frames). Conclusion: segments structurally exist but contain NO video frames — they are Blob OBJECTS with valid track metadata but empty Cluster sections. This rules out Hypothesis A (segments lost across SW termination) at the structural level."
+
+- timestamp: "2026-05-21T20:00Z (Step C spike: SPIKE_SKIP_SW_KILL=1)"
+  checked: "HEADLESS=1 SPIKE_SKIP_SW_KILL=1 npx tsx tests/uat/spike-a33-sw-persistence.ts → /tmp/04-04-debug-step-c.log"
+  found: "Identical 8505-byte videoSize. Crucially, since SW was NOT killed, its console listener stayed connected, so we see the FULL Remux pipeline output: 'Remuxing 3 segments; sizes: [array Array]' followed by 'Segment ts=1: 0 frames, duration=0ms, trackInfo=320x180' (and identical lines for ts=2 + ts=3) and 'Remux complete: 0 frames, total timeline=0ms, output=8505 bytes'."
+  implication: "DEFINITIVE: each of the 3 segments has a valid track header (trackInfo=320x180 was parsed from each) but ZERO VP9 frames. The Remuxer faithfully emitted an 8505-byte WebM containing only EBML headers + Segment + Tracks + Cues (no Clusters). The 5-min headless idle window prevented MediaRecorder from receiving frame data from the canvas-captureStream source despite the offscreen-hooks setInterval(drawFrame, 33) belt-and-suspenders. Hypothesis B (canvas-captureStream throttling) is empirically confirmed; Hypothesis C (CDP-induced teardown) is empirically refuted (Step C removed the CDP-kill and the failure persisted)."
+
+- timestamp: "2026-05-21T20:30Z (diagnostic spike — tests/uat/spike-diagnose-offscreen-target.ts)"
+  checked: "Puppeteer browser.targets() enumeration with active offscreen recording (post-assertA2 prime)"
+  found: "browser.targets() count=7 targets. Offscreen reported as: type=background_page url=chrome-extension://{id}/src/offscreen/index.html. Crucially, the targetcreated event fires for the offscreen with type='other' and url='' (metadata not yet stabilized at create time); type+url stabilize AFTER the target's first navigation completes."
+  implication: "ROOT CAUSE OF SESSION-1 OBSERVABILITY BUG: the launch.ts `targetcreated` listener checked target.type() and target.url() at event time, but the metadata is unstable at that instant. The original `type==='background_page'` filter was actually CORRECT for the stable enumeration — it failed only because checked at the wrong time. Fix: bind to BOTH 'targetcreated' AND 'targetchanged' (the latter fires when URL stabilizes) + enumerate `browser.targets()` as a race-free safety net. URL pattern is the load-bearing match criterion; type-based discrimination is unreliable across event timings."
+
+- timestamp: "2026-05-21T20:31Z (verification — diagnostic with the fix in place)"
+  checked: "HEADLESS=1 npx tsx tests/uat/spike-diagnose-offscreen-target.ts → grep [off:"
+  found: "[off:log] [OS:Recorder] Recording started (D-13 restart-segments), mime: video/webm;codecs=vp9 segment_ms: 10000 max_segments: 3"
+  implication: "Step A fix verified — offscreen console capture now functional. The (launch: offscreen console attached — url=...) diagnostic confirms the attach happened via the targetchanged event after the URL stabilized."
+
+## Resolution
+
+root_cause: "Test methodology (NOT production architecture). The spike's `installFakeDisplayMedia()` synthetic stream (canvas.captureStream(30) on a hidden 320x180 canvas appended to the offscreen DOM, offset to -9999px) cannot sustain frame production during a 5-min wall-clock idle window in headless Chrome. The offscreen-hooks setInterval(drawFrame, 33ms) belt-and-suspenders is INSUFFICIENT to mitigate the documented Chromium auto-throttling of MediaRecorder on invisible-canvas sources (Chrome bug 653548, auto-throttled-screen-capture design doc, sendrec.eu blog 'Why Canvas Breaks Your Screen Recorder'). The MediaRecorder produces structurally-valid WebM segments (EBML header + Tracks block parses correctly; trackInfo=320x180 extracted) but each segment's Cluster section is empty. The Remuxer faithfully emits a header-only 8505-byte WebM."
+
+fix: "Plan 04-04 spike's test methodology needs replacement. The architecture (offscreen-RAM segments: Blob[] = []) is sound; it correctly preserves the 3 segments across SW kill (proven by post-kill probe = 3). RECOMMENDATIONS (out of scope for this debug session): (a) reframe SC#1 verification to use real getDisplayMedia in non-headless Puppeteer with --auto-select-desktop-capture-source (currently rejected per 01-11-SUMMARY falsification 4 as 'unreliable in headless'; may be reliable in non-headless); OR (b) replace the canvas-captureStream fake with a video-file-backed source (e.g., MediaStream from an HTMLVideoElement playing a bundled WebM) which doesn't suffer the invisible-canvas throttling; OR (c) lower SC#1's wall-clock idle threshold to a value short enough that canvas-captureStream survives (e.g., 30s) AND add a separate manual operator-empirical test for the full 5-min case. The ARCHITECTURAL change (IndexedDB persistence) recommended in Plan 04-04 SUMMARY would NOT close SC#1 — the spike would STILL produce 8505 bytes after IDB lands because the failure is in the test's fake stream, not in segment persistence."
+
+verification: "Three independent spike runs converge: (1) canonical with broken observability → 8505 bytes; pre-kill probe count=3, post-kill count=3. (2) canonical with race-fixed observability (post-Step-A) → 8505 bytes; pre-kill count=3, post-kill count=3. (3) Step C variant (skip worker.close()) → 8505 bytes; Remux output explicitly shows '0 frames' for each segment. The architecture works (segments survive); the test methodology is broken (segments are 0-frame Blobs)."
+
+files_changed:
+  - "tests/uat/lib/launch.ts (Step A fix — race-tolerant offscreen target attach: bind targetcreated AND targetchanged + browser.targets() enumeration; URL-based match; updated docstrings citing empirical evidence)"
+  - "tests/uat/spike-a33-sw-persistence.ts (Step B — added `probeSegmentCount` helper using existing `__mokoshOffscreenQuery` 'get-segment-count' bridge op; 3 probes at POST-PRIME/PRE-KILL/POST-KILL; Step C — added SPIKE_SKIP_SW_KILL=1 mode that skips the worker.close() call)"
+  - "tests/uat/spike-diagnose-offscreen-target.ts (NEW — one-off diagnostic script that enumerated browser.targets() to reveal the Puppeteer event-timing bug; safe to keep committed as a future SW-lifecycle debugging tool)"
+  - ".planning/debug/sw-offscreen-persistence-investigation-session-2.md (NEW — this debug note)"
+
+## Synthesis — Verdict Decision Tree
+
+Per the disambiguation_protocol Step D:
+
+- **CONFIRMED-architecture:** REJECTED. Segments survive SW kill; pre/post-kill counts both = 3. Removing the SW kill (Step C) does NOT improve outcome. Persistence is not the issue.
+
+- **REFUTED-architecture (canvas-captureStream issue):** CONFIRMED.
+  - Pre-kill probe: count=3 → segments accumulated correctly.
+  - Step C (no kill) → identical 8505-byte failure.
+  - Direct Remux log evidence: `Segment ts=1: 0 frames, duration=0ms, trackInfo=320x180` × 3.
+  - Documented Chromium throttling behavior matches exactly: invisible-canvas MediaRecorder → near-zero frame production over time.
+  - Setinterval(drawFrame, 33) workaround empirically insufficient against the actual throttling path (canvas pixels change BUT captureStream track stops emitting frames).
+
+- **REFUTED-architecture (CDP artifact):** REJECTED. Step C (without worker.close()) produces same failure. CDP attach is not the cause.
+
+- **STILL-INCONCLUSIVE:** REJECTED. The three independent observations (segment count, Step-C, Remux logs) converge unambiguously on canvas-captureStream throttling.
+
+**Routing recommendation:** Do NOT proceed with the IndexedDB persistence plan-fix proposed by Plan 04-04 SUMMARY. Open a new plan slot (likely Plan 04-08 or a Phase 5 plan) that reframes SC#1 verification methodology. Architecture is sound; verification gate is broken.
diff --git a/tests/uat/spike-a33-sw-persistence.ts b/tests/uat/spike-a33-sw-persistence.ts
index 092888d..a482a9b 100644
--- a/tests/uat/spike-a33-sw-persistence.ts
+++ b/tests/uat/spike-a33-sw-persistence.ts
@@ -1,4 +1,5 @@
-// tests/uat/spike-a33-sw-persistence.ts — Plan 04-04 Wave 0 SPIKE.
+// tests/uat/spike-a33-sw-persistence.ts — Plan 04-04 Wave 0 SPIKE +
+// Plan-04-04 debug session-2 disambiguation probes.
 //
 // One-shot empirical investigation: does the offscreen document survive
 // a 5-min idle window followed by Puppeteer-driven force-termination
@@ -8,6 +9,19 @@
 // is MEDIUM because the Chrome docs leave the offscreen-vs-SW interplay
 // implicit. This spike is the empirical hedge.
 //
+// Session-2 disambiguation (committed alongside debug
+// session-2 note .planning/debug/sw-offscreen-persistence-investigation-session-2.md):
+//   - get-segment-count probes at 3 checkpoints (post-prime, pre-kill,
+//     post-kill-pre-SAVE) — distinguishes "segments empty pre-kill
+//     (canvas-captureStream throttled)" from "segments existed pre-kill
+//     but lost post-kill (architectural)". Probes ride the production
+//     __mokoshOffscreenQuery bridge op (already in FORBIDDEN_HOOK_STRINGS
+//     inventory); no new test-only symbols introduced.
+//   - SPIKE_SKIP_SW_KILL=1 env-var skips the worker.close() call —
+//     distinguishes "SW kill via CDP causes the failure (CDP artifact)"
+//     from "5-min idle alone causes the failure (architectural OR
+//     canvas-throttling-without-SW-involvement)".
+//
 // Outcome decision tree:
 //   - videoSize > 100_000 bytes → SPIKE PASSED. Plan 04-04 Wave 1
 //     proceeds: A33 is a verification-only harness assertion that
@@ -63,16 +77,99 @@ const SPIKE_DOWNLOAD_SETTLE_MS = 5_000;
  *  meta.json + screenshot is ~50 KB; anything above 100 KB means the
  *  video buffer actually contained segments). */
 const SPIKE_VIDEO_SIZE_FLOOR_BYTES = 100_000;
+/** Session-2: probe op timeout (5s; matches the harness's offscreenQuery default). */
+const SPIKE_PROBE_TIMEOUT_MS = 5_000;
+
+/**
+ * Session-2 disambiguation probe — query the offscreen recorder's live
+ * `segments.length` via the production `__mokoshOffscreenQuery`
+ * `get-segment-count` bridge op (src/test-hooks/offscreen-hooks.ts:493).
+ *
+ * Returns the segment count (number of fully-rotated 10s WebM segments
+ * in the in-memory ring buffer), or `-1` on bridge error.
+ *
+ * The bridge op rides chrome.runtime.sendMessage from the harness page
+ * realm → offscreen-hooks's onMessage listener responds synchronously
+ * via sendResponse({count: number}). No new test-hook symbol; the
+ * `get-segment-count` op is already in the 12-entry FORBIDDEN_HOOK_STRINGS
+ * inventory (Plan 01-13 Wave 3D A11 contract).
+ *
+ * Used at 3 checkpoints in the spike:
+ *   1. post-prime: confirms baseline segment-count ≈ 0 (no rotations yet)
+ *      — sanity check; if NON-zero here, the prime did unexpected work.
+ *   2. pre-kill (just BEFORE stopServiceWorker): the critical probe —
+ *      if zero here, hypothesis B (canvas-throttling) confirmed;
+ *      if non-zero here but archive empty post-SAVE, hypothesis A
+ *      (architectural RAM loss across SW termination) confirmed.
+ *   3. post-kill-pre-SAVE: confirms offscreen still respawns + can
+ *      respond — if the offscreen target itself died with the SW kill,
+ *      this probe would throw or time out; that result distinguishes
+ *      "offscreen survives kill but loses state" from "offscreen dies
+ *      with the SW kill (collateral teardown per Puppeteer #9995)".
+ *
+ * @param page - The harness page (has chrome.runtime access).
+ * @returns The live segment count, or `-1` on probe error.
+ */
+async function probeSegmentCount(
+  page: import('puppeteer').Page,
+  label: string,
+): Promise<number> {
+  try {
+    const result = await page.evaluate(
+      (timeoutMs: number) =>
+        new Promise<{ count?: number; error?: string }>((resolve) => {
+          const timer = setTimeout(() => {
+            resolve({ error: `get-segment-count timed out after ${timeoutMs}ms` });
+          }, timeoutMs);
+          chrome.runtime.sendMessage(
+            { type: '__mokoshOffscreenQuery', op: 'get-segment-count' },
+            (response: unknown) => {
+              clearTimeout(timer);
+              if (chrome.runtime.lastError !== undefined) {
+                resolve({ error: String(chrome.runtime.lastError.message) });
+                return;
+              }
+              resolve(response as { count?: number; error?: string });
+            },
+          );
+        }),
+      SPIKE_PROBE_TIMEOUT_MS,
+    );
+    if (typeof result.count === 'number') {
+      process.stdout.write(
+        `SPIKE PROBE [${label}]: segments.length=${result.count}\n`,
+      );
+      return result.count;
+    }
+    process.stdout.write(
+      `SPIKE PROBE [${label}]: ERROR ${result.error ?? '(unknown)'}\n`,
+    );
+    return -1;
+  } catch (err) {
+    process.stdout.write(
+      `SPIKE PROBE [${label}]: THREW ${err instanceof Error ? err.message : String(err)}\n`,
+    );
+    return -1;
+  }
+}
 
 /**
  * Spike entrypoint. Returns a Node exit code (0 = PASSED, 1 = FAILED).
  */
 async function main(): Promise<number> {
+  // Session-2 mode switch: SPIKE_SKIP_SW_KILL=1 = run Step C variant
+  // (5-min idle + SAVE, NO worker.close()). Distinguishes "SW kill is
+  // the cause" from "5-min idle alone is the cause".
+  const skipSwKill = process.env.SPIKE_SKIP_SW_KILL === '1';
+
   process.stdout.write('\nMokosh Plan 04-04 Wave 0 SPIKE — SW state persistence empirical test\n');
   process.stdout.write('='.repeat(72) + '\n');
   process.stdout.write(
     `SPIKE: idle window = ${SPIKE_IDLE_WAIT_MS}ms (${SPIKE_IDLE_WAIT_MS / 60_000} min); ` +
-      `pass floor = ${SPIKE_VIDEO_SIZE_FLOOR_BYTES} bytes\n\n`,
+      `pass floor = ${SPIKE_VIDEO_SIZE_FLOOR_BYTES} bytes\n`,
+  );
+  process.stdout.write(
+    `SPIKE: mode = ${skipSwKill ? 'STEP-C (skip-sw-kill: 5-min idle + SAVE, no worker.close)' : 'CANONICAL (5-min idle + worker.close + SAVE)'}\n\n`,
   );
 
   const t0 = Date.now();
@@ -108,20 +205,55 @@ async function main(): Promise<number> {
       throw new Error(`assertA2 priming failed: ${a2Result.error ?? '(no error)'}`);
     }
 
+    // Session-2 PROBE 1: post-prime baseline. Expected: 0 (no segment
+    // rotation has happened yet; A2's prime takes <1s + first rotation
+    // is at +10s).
+    await probeSegmentCount(handles.harnessPage, 'POST-PRIME');
+
     // Step 2 — 5-min wall-clock idle. The whole point of the spike.
     process.stdout.write(`\nSPIKE Step 2: waiting ${SPIKE_IDLE_WAIT_MS}ms for SW idle window...\n`);
     process.stdout.write(`SPIKE Step 2: ETA ${new Date(Date.now() + SPIKE_IDLE_WAIT_MS).toISOString()}\n`);
     await new Promise((res) => setTimeout(res, SPIKE_IDLE_WAIT_MS));
     process.stdout.write('SPIKE Step 2 OK — 5-min idle elapsed\n');
 
-    // Step 3 — force-terminate the SW via Puppeteer CDP worker.close().
-    process.stdout.write('\nSPIKE Step 3: stopServiceWorker(browser, extensionId)\n');
-    await stopServiceWorker(handles.browser, handles.extensionId);
-    process.stdout.write('SPIKE Step 3 OK — SW terminated via worker.close()\n');
+    // Session-2 PROBE 2: pre-kill — THE critical disambiguation point.
+    // If count==0 here: hypothesis B (canvas-captureStream throttled in
+    //   headless idle; segments never accumulated). Architecture NOT broken.
+    // If count>=3 here: hypothesis A (architectural RAM loss across SW
+    //   termination); the test is correct; segments existed pre-kill.
+    //   Then check post-SAVE archive: if also empty, IDB persistence needed.
+    // If count==-1 (probe failed): offscreen is unresponsive — either
+    //   collateral-killed already (unlikely; no worker.close yet) or
+    //   SW had to broker and SW is also unresponsive.
+    const segCountPreKill = await probeSegmentCount(handles.harnessPage, 'PRE-KILL');
+
+    if (skipSwKill) {
+      // Step C variant — skip the SW kill entirely. Use the same 500ms
+      // settle as the canonical path so the timing between SAVE dispatch
+      // and zip mtime stays consistent across runs.
+      process.stdout.write(
+        '\nSPIKE Step 3: SKIPPED (SPIKE_SKIP_SW_KILL=1) — testing 5-min idle alone\n',
+      );
+    } else {
+      // Step 3 — force-terminate the SW via Puppeteer CDP worker.close().
+      process.stdout.write('\nSPIKE Step 3: stopServiceWorker(browser, extensionId)\n');
+      await stopServiceWorker(handles.browser, handles.extensionId);
+      process.stdout.write('SPIKE Step 3 OK — SW terminated via worker.close()\n');
+    }
 
     // Step 4 — brief settle for SW teardown.
     await new Promise((res) => setTimeout(res, SPIKE_NEW_SW_BOOT_MS));
 
+    // Session-2 PROBE 3: post-kill (or post-skip-kill) — confirms
+    // offscreen is still responsive after worker.close. If count drops
+    // from pre-kill value, the SW kill collaterally destroyed offscreen
+    // state. If count is same (or grows by 1 due to a rotation between
+    // probes), offscreen survived.
+    const segCountPostKill = await probeSegmentCount(handles.harnessPage, skipSwKill ? 'POST-SKIP-KILL' : 'POST-KILL');
+    process.stdout.write(
+      `SPIKE: segment-count transition: pre=${segCountPreKill}, post=${segCountPostKill}\n`,
+    );
+
     // Step 5 — dispatch SAVE_ARCHIVE via chrome.runtime.sendMessage from
     // the harness page realm. The first message after worker.close()
     // wakes the SW back up (event-driven respawn — canonical MV3 wakeup
@@ -177,7 +309,10 @@ async function main(): Promise<number> {
   const elapsedSec = (tEnd - t0) / 1000;
 
   process.stdout.write('\n' + '='.repeat(72) + '\n');
-  process.stdout.write(`SPIKE RESULT: videoSize=${videoSize} bytes (floor=${SPIKE_VIDEO_SIZE_FLOOR_BYTES}; elapsed=${elapsedSec.toFixed(1)}s)\n`);
+  process.stdout.write(
+    `SPIKE RESULT [${skipSwKill ? 'STEP-C-NO-KILL' : 'CANONICAL'}]: ` +
+      `videoSize=${videoSize} bytes (floor=${SPIKE_VIDEO_SIZE_FLOOR_BYTES}; elapsed=${elapsedSec.toFixed(1)}s)\n`,
+  );
   if (spikeError !== null) {
     process.stdout.write(`SPIKE OUTCOME: FAILED (spike threw: ${spikeError})\n`);
     process.stdout.write('='.repeat(72) + '\n');