From c02914df867c8efb6ec2bc0c0b3753f4db5b7726 Mon Sep 17 00:00:00 2001 From: Mark Date: Wed, 20 May 2026 19:11:41 +0200 Subject: [PATCH 1/3] =?UTF-8?q?feat(03-01):=20Task=201=20=E2=80=94=20probe?= =?UTF-8?q?=20HTML=20for=20A29=20rrweb=20DOM=20verification=20(SPEC=20?= =?UTF-8?q?=C2=A710=20#4)?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Append form (text + email + password + submit) + table (thead + 2 rows) + modal trigger + hidden modal div below existing `
`
  scaffold; preserves `` block + tokens.css link untouched (A18/A21
  invariant).
- Modal trigger uses inline onclick to toggle style.display — rrweb
  records the attribute mutation, satisfying IncrementalSnapshot
  emission per RESEARCH Pitfall 1 (synthetic probe HTML emits Meta +
  FullSnapshot but NOT IncrementalSnapshot without a DOM mutation
  between page load and SAVE).
- Per RESEARCH Pitfall 4: the rrweb-alpha.4-leaky multi-line input
  element (rrweb-io/rrweb#1596) is excluded; only single-line inputs.
- Per UI-SPEC §"Test Fixture Conventions": data-test-* attributes
  only; no data-mokosh-* (production-welcome-page reserved); no
  tokens.css import on the probe sub-tree (head already imports the
  canonical tokens for A18/A21).
- npm run build exit 0; all 7 acceptance grep gates GREEN.
---
 tests/uat/extension-page-harness.html | 36 +++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/tests/uat/extension-page-harness.html b/tests/uat/extension-page-harness.html
index 84a5134..94888be 100644
--- a/tests/uat/extension-page-harness.html
+++ b/tests/uat/extension-page-harness.html
@@ -19,6 +19,42 @@
     
This page lives at chrome-extension://<id>/tests/uat/extension-page-harness.html.

     
Puppeteer navigates a tab here and drives assertions via window.__mokoshHarness.*.

     
Ready.

+    
+    

+      
+      
+      
+      
+    

+    
+      
+        
+      
+      
+        
+        
+      
+    
col-acol-b
row-1-arow-1-b
row-2-arow-2-b

+    
+    
     
   
 

From cc13f319a10b10948d8e5628b4ac6f9f4a6cac19 Mon Sep 17 00:00:00 2001
From: Mark 
Date: Wed, 20 May 2026 19:17:47 +0200
Subject: [PATCH 2/3] =?UTF-8?q?feat(03-01):=20Task=202=20=E2=80=94=20asser?=
 =?UTF-8?q?tA29=20+=20driveA29=20+=20orchestrator=20wiring=20(A29=2030/30?=
 =?UTF-8?q?=20GREEN)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Page-side (tests/uat/extension-page-harness.ts):
- assertA29 dispatches probe-page DOM mutation (input value + modal
  toggle), settles 500ms for rrweb IncrementalSnapshot to enqueue,
  setupFreshRecording, 11s segment-settle, SAVE_ARCHIVE; pushes
  A29.1 SAVE ack check. Module-local constants:
  A29_SAVE_ARCHIVE_TIMEOUT_MS=15s, A29_SEGMENT_SETTLE_MS=11s,
  A29_MUTATION_SETTLE_MS=500ms.
- declare global interface + window.__mokoshHarness object literal
  extended with assertA29 (single-method-per-assertion contract).
- statusEl + console banner updated A28 → A29 + cite Plan 03-01.

Host-side (tests/uat/lib/harness-page-driver.ts):
- Add `import { EventType } from '@rrweb/types';`.
- driveA29 — 3-phase orchestration mirroring driveA26:
  Phase 1 page.evaluate harness.assertA29(); Phase 2 findLatestZip;
  Phase 3 JSZip.loadAsync rrweb/session.json + EventType grep.
  Appends A29.0a (rrweb/session.json present) + A29.2..A29.5
  (events.length>0 + Meta + FullSnapshot + IncrementalSnapshot).

Orchestrator (tests/uat/harness.test.ts):
- driveA29 imported after driveA28.
- driveA29Wrapped const captures handles.downloadsDir.
- drivers array push A29 entry with banner citing Plan 03-01 + Pitfall 1.
- Architecture banner string updated A28 → A29.

Empirical verification (HEADLESS=1 SKIP_PROD_REBUILD=0 npm run test:uat):
- UAT harness: 30/30 GREEN (29 prior + A29 NEW).
- A29 events.length=4; event types observed: 2, 3, 4 (FullSnapshot,
  IncrementalSnapshot, Meta — all three required types present).
- Pitfall 1 mitigation empirically verified — the pre-SAVE DOM
  mutation produced the IncrementalSnapshot.
- vitest 171/171 GREEN preserved (full suite).
- Tier-1 FORBIDDEN_HOOK_STRINGS unit gate 13/13 GREEN (12 strings × 0
  hits each) — A29 rides production rrweb wiring + GET_RRWEB_EVENTS
  bridge + sendMessageWithTimeout helper; NO new __MOKOSH_UAT__
  symbols.
- npx tsc --noEmit exit 0.
---
 tests/uat/extension-page-harness.ts  | 110 ++++++++++++++++++-
 tests/uat/harness.test.ts            |  15 ++-
 tests/uat/lib/harness-page-driver.ts | 151 +++++++++++++++++++++++++++
 3 files changed, 273 insertions(+), 3 deletions(-)

diff --git a/tests/uat/extension-page-harness.ts b/tests/uat/extension-page-harness.ts
index c9feef6..f56b8fa 100644
--- a/tests/uat/extension-page-harness.ts
+++ b/tests/uat/extension-page-harness.ts
@@ -3315,6 +3315,109 @@ async function assertA28(): Promise {
   };
 }
 
+/* ─── Plan 03-01 Task 2 — A29 (rrweb DOM verification; SPEC §10 #4) ─
+ *
+ *   A29 — REQ-rrweb-dom-buffer empirical: rrweb's record() (already
+ *         wired at src/content/index.ts:285) emits Meta + FullSnapshot
+ *         + at least one IncrementalSnapshot when the harness page
+ *         contains the probe HTML (form + table + modal) AND the driver
+ *         injects a DOM mutation before SAVE (RESEARCH Pitfall 1:
+ *         static probe HTML emits Meta + FullSnapshot but not
+ *         IncrementalSnapshot without mutation).
+ *
+ * Page side: dispatch the probe-page DOM mutations (input value +
+ * modal toggle), settle, setupFreshRecording, settle one segment,
+ * dispatch SAVE_ARCHIVE, push A29.1 ack check. The host-side driveA29
+ * does the EventType-enum-shape grep against rrweb/session.json from
+ * the assembled zip (matches A26's chained-assertion pattern; JSZip
+ * + @rrweb/types are host-only deps).
+ *
+ * FORBIDDEN_HOOK_STRINGS impact: NONE. A29 rides production rrweb
+ * wiring (record() at src/content/index.ts:285 + GET_RRWEB_EVENTS
+ * round-trip at src/background/index.ts → src/content/index.ts:318)
+ * + the existing setupFreshRecording / sendMessageWithTimeout
+ * helpers. Tier-1 inventory stays at 12 entries.
+ */
+
+/** SAVE_ARCHIVE dispatch timeout for A29 — matches A24/A25/A27. */
+const A29_SAVE_ARCHIVE_TIMEOUT_MS = 15_000;
+/** Pre-SAVE segment-settle window (10s rotation + 1s slack). */
+const A29_SEGMENT_SETTLE_MS = 11_000;
+/** Settle window between DOM mutation and SAVE so rrweb's
+ *  IncrementalSnapshot lands in the in-memory buffer before
+ *  GET_RRWEB_EVENTS fires. */
+const A29_MUTATION_SETTLE_MS = 500;
+
+/**
+ * A29 — rrweb DOM event recording empirical (SPEC §10 #4).
+ *
+ * Page-side dispatches the probe-page mutation (input.value + modal
+ * toggle), settles, runs setupFreshRecording + segment-settle, then
+ * dispatches SAVE_ARCHIVE. Only the SAVE ack lives in the
+ * page-side checks; the EventType-enum-shape grep is host-side
+ * because @rrweb/types is host-only.
+ *
+ * @returns AssertionResult with 1 page-side check (SAVE ack); host-side
+ *          driveA29 appends A29.0a/A29.2..A29.5 EventType checks.
+ */
+async function assertA29(): Promise {
+  const result: AssertionResult = {
+    passed: false,
+    name: 'A29 — rrweb DOM events recorded without errors (SPEC §10 #4 / REQ-rrweb-dom-buffer)',
+    checks: [],
+    diagnostics: [],
+  };
+
+  try {
+    diag(result, 'Step 1: dispatch probe-page DOM mutation (input value + modal toggle)');
+    const textInput = document.querySelector('#probe-text');
+    if (textInput !== null) {
+      textInput.value = 'probe';
+      textInput.dispatchEvent(new Event('input', { bubbles: true }));
+    }
+    const modalTrigger = document.querySelector('#probe-modal-trigger');
+    if (modalTrigger !== null) {
+      modalTrigger.click();
+    }
+    diag(result, `Step 1 OK — mutations dispatched (#probe-text=${textInput !== null}, #probe-modal-trigger=${modalTrigger !== null})`);
+
+    diag(result, `Step 2: settle ${A29_MUTATION_SETTLE_MS}ms for rrweb IncrementalSnapshot to enqueue`);
+    await new Promise((r) => setTimeout(r, A29_MUTATION_SETTLE_MS));
+
+    diag(result, 'Step 3: setupFreshRecording');
+    const setupResp = await setupFreshRecording();
+    if (!setupResp.ok) {
+      throw new Error(`setupFreshRecording failed: ${setupResp.error ?? '(no error)'}`);
+    }
+    diag(result, 'Step 3 OK — REC state established');
+
+    diag(result, `Step 4: settle ${A29_SEGMENT_SETTLE_MS}ms for first segment rotation`);
+    await new Promise((r) => setTimeout(r, A29_SEGMENT_SETTLE_MS));
+
+    diag(result, 'Step 5: dispatch SAVE_ARCHIVE');
+    const ack = await sendMessageWithTimeout<{ success: boolean; error?: string }>(
+      { type: 'SAVE_ARCHIVE' },
+      A29_SAVE_ARCHIVE_TIMEOUT_MS,
+      'SAVE_ARCHIVE (A29)',
+    );
+    diag(result, `Step 5 result: ${JSON.stringify(ack)}`);
+
+    result.checks.push({
+      name: 'A29.1: SAVE_ARCHIVE ack received with success=true',
+      expected: true,
+      actual: ack.success,
+      passed: ack.success === true,
+    });
+
+    result.passed = result.checks.every((c) => c.passed);
+  } catch (err) {
+    result.error = err instanceof Error ? err.message : String(err);
+    diag(result, `THREW: ${result.error}`);
+  }
+
+  return result;
+}
+
 /**
  * Read `chrome.runtime.getManifest().version`. Used by the host-side
  * orchestrator at startup to capture the expected version for A13's
@@ -3366,6 +3469,8 @@ declare global {
       assertA26: () => Promise;
       assertA27: () => Promise;
       assertA28: () => Promise;
+      // Plan 03-01 — rrweb DOM verification (SPEC §10 #4)
+      assertA29: () => Promise;
       getManifestVersion: () => Promise;
     };
   }
@@ -3400,14 +3505,15 @@ window.__mokoshHarness = {
   assertA26,
   assertA27,
   assertA28,
+  assertA29,
   getManifestVersion,
 };
 
 const statusEl = document.getElementById('status');
 if (statusEl !== null) {
-  statusEl.textContent = 'Harness ready. window.__mokoshHarness.{assertA1..A28, getManifestVersion} available.';
+  statusEl.textContent = 'Harness ready. window.__mokoshHarness.{assertA1..A29, getManifestVersion} available.';
 }
 
-console.log('[harness-page] ready — window.__mokoshHarness installed (Plan 01-13 Task 9: A1..A14 + Plan 01-10 Wave 3: A15..A17 + Plan 01-12 Wave 6: A18..A22 + Plan 01-14: A23 + Plan 02-04 Tasks 1-2: A24+A25 + Plan 02-04 Task 3: A26+A27+A28 + getManifestVersion)');
+console.log('[harness-page] ready — window.__mokoshHarness installed (Plan 01-13 Task 9: A1..A14 + Plan 01-10 Wave 3: A15..A17 + Plan 01-12 Wave 6: A18..A22 + Plan 01-14: A23 + Plan 02-04 Tasks 1-2: A24+A25 + Plan 02-04 Task 3: A26+A27+A28 + Plan 03-01: A29 + getManifestVersion)');
 
 export {};
diff --git a/tests/uat/harness.test.ts b/tests/uat/harness.test.ts
index eb3d315..f9ec2e6 100644
--- a/tests/uat/harness.test.ts
+++ b/tests/uat/harness.test.ts
@@ -97,6 +97,8 @@ import {
   driveA26,
   driveA27,
   driveA28,
+  // Plan 03-01 — rrweb DOM verification (SPEC §10 #4 / REQ-rrweb-dom-buffer)
+  driveA29,
   getManifestVersion,
 } from './lib/harness-page-driver';
 import {
@@ -265,7 +267,7 @@ async function assertA0_GrepGate(): Promise<{
  */
 async function main(): Promise {
   process.stdout.write('\nMokosh Plan 01-13 + 01-14 + 02-04 — UAT harness orchestrator\n');
-  process.stdout.write('Architecture: A0 pre-flight + extension-internal page driver (A1..A14, A15..A17, A18..A22, A23, A24, A25, A26, A27, A28)\n');
+  process.stdout.write('Architecture: A0 pre-flight + extension-internal page driver (A1..A14, A15..A17, A18..A22, A23, A24, A25, A26, A27, A28, A29)\n');
   process.stdout.write('='.repeat(72) + '\n');
 
   // A0 pre-flight (no Chrome launch needed; runs against built dist/).
@@ -333,6 +335,10 @@ async function main(): Promise {
     (page) => driveA27(page, handles.downloadsDir);
   const driveA28Wrapped: (page: import('puppeteer').Page) => Promise =
     (page) => driveA28(page, handles.downloadsDir);
+  // Plan 03-01 — driveA29 needs downloadsDir for host-side JSZip parse
+  // of rrweb/session.json from the just-produced zip.
+  const driveA29Wrapped: (page: import('puppeteer').Page) => Promise =
+    (page) => driveA29(page, handles.downloadsDir);
 
   const drivers: ReadonlyArray<{
     readonly name: string;
@@ -428,6 +434,13 @@ async function main(): Promise {
     // and asserts EXACTLY 5 paths: video/last_30sec.webm, rrweb/session.json,
     // logs/events.json, screenshot.png, meta.json (set-equality; no extras).
     { name: 'A28', drive: driveA28Wrapped },
+    // Plan 03-01 A29: rrweb DOM verification (SPEC §10 #4).
+    // A29 owns its SAVE because the probe-page DOM mutation must
+    // happen between page load and SAVE so rrweb's IncrementalSnapshot
+    // fires (RESEARCH Pitfall 1). Host-side driveA29 JSZip-parses
+    // rrweb/session.json and asserts the EventType enum surfaces
+    // (Meta=4, FullSnapshot=2, IncrementalSnapshot=3) are present.
+    { name: 'A29', drive: driveA29Wrapped },
   ];
 
   const buffers = { swConsole: handles.swConsole, offConsole: handles.offConsole };
diff --git a/tests/uat/lib/harness-page-driver.ts b/tests/uat/lib/harness-page-driver.ts
index b1c572f..8ca1afe 100644
--- a/tests/uat/lib/harness-page-driver.ts
+++ b/tests/uat/lib/harness-page-driver.ts
@@ -39,6 +39,7 @@ import { tmpdir } from 'node:os';
 import { join, resolve as resolvePath } from 'node:path';
 
 import JSZip from 'jszip';
+import { EventType } from '@rrweb/types';
 import type { Page } from 'puppeteer';
 
 import type { AssertionRecord, CheckRecord } from './assertions';
@@ -1847,3 +1848,153 @@ export async function driveA28(
     error: pageResult.error,
   };
 }
+
+/* ─── Plan 03-01 — driveA29 (rrweb DOM verification host-side) ─────── */
+
+/**
+ * Drive A29 (Plan 03-01 — SPEC §10 #4 / REQ-rrweb-dom-buffer).
+ *
+ * Three-phase orchestration:
+ *   1. Page-side assertA29 dispatches the probe DOM mutations, settles,
+ *      runs setupFreshRecording, settles a segment, dispatches SAVE.
+ *      Returns AssertionRecord with A29.1 (SAVE ack) only.
+ *   2. Host-side findLatestZip picks the just-produced zip (mtime-sort
+ *      wins; race-free per Plan 02-04 precedent — assertA29 awaits the
+ *      SAVE ack before returning so the zip has landed by here).
+ *   3. Host-side JSZip-parse rrweb/session.json + EventType-enum grep.
+ *
+ * Checks appended host-side:
+ *   - A29.0: at least one zip present in downloadsDir
+ *   - A29.0a: rrweb/session.json entry exists in zip
+ *   - A29.1 (already from page side): SAVE_ARCHIVE ack success
+ *   - A29.2: events.length > 0
+ *   - A29.3: events.some(e => e.type === EventType.Meta)
+ *   - A29.4: events.some(e => e.type === EventType.FullSnapshot)
+ *   - A29.5: events.some(e => e.type === EventType.IncrementalSnapshot)
+ *
+ * RESEARCH Pitfall 1 mitigation: the page-side dispatches a real DOM
+ * mutation (input value + modal toggle) BEFORE SAVE so the
+ * IncrementalSnapshot check (A29.5) has actual content to find.
+ *
+ * @param page         - The harness page from `launchHarnessBrowser`.
+ * @param downloadsDir - Absolute path to the per-run downloads directory.
+ * @returns AssertionRecord with 6 merged checks (A29.0a + A29.1..A29.5).
+ */
+export async function driveA29(
+  page: Page,
+  downloadsDir: string,
+): Promise {
+  // Phase 1 — page-side orchestration + SAVE.
+  const pageResult = await page.evaluate(async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- evaluate runs in browser context where Window types are loose.
+    const harness = (window as any).__mokoshHarness;
+    const r: AssertionRecord = await harness.assertA29();
+    return r;
+  }) as AssertionRecord;
+
+  const mergedChecks: CheckRecord[] = pageResult.checks.slice();
+  const mergedDiagnostics: string[] = pageResult.diagnostics.slice();
+
+  // Phase 2 — locate the produced zip.
+  const zipPath = findLatestZip(downloadsDir);
+  if (zipPath === null) {
+    mergedChecks.push({
+      name: 'A29.0: at least one zip present in downloadsDir',
+      expected: '>=1 zip',
+      actual: 'no zip in downloadsDir',
+      passed: false,
+    });
+    return {
+      passed: false,
+      name: pageResult.name,
+      checks: mergedChecks,
+      diagnostics: mergedDiagnostics,
+      error: pageResult.error,
+    };
+  }
+  mergedDiagnostics.push(`A29 zipPath=${zipPath}`);
+
+  // Phase 3 — load + inspect rrweb/session.json.
+  const zipBytes = readFileSync(zipPath);
+  const zip = await JSZip.loadAsync(zipBytes);
+  const rrwebFile = zip.file('rrweb/session.json');
+  mergedChecks.push({
+    name: 'A29.0a: rrweb/session.json entry exists in zip',
+    expected: true,
+    actual: rrwebFile !== null,
+    passed: rrwebFile !== null,
+  });
+
+  if (rrwebFile === null) {
+    return {
+      passed: false,
+      name: pageResult.name,
+      checks: mergedChecks,
+      diagnostics: mergedDiagnostics,
+      error: pageResult.error,
+    };
+  }
+
+  const rrwebText = await rrwebFile.async('string');
+  let events: Array<{ type: number; timestamp: number }> = [];
+  let parseErr: string | null = null;
+  try {
+    events = JSON.parse(rrwebText) as Array<{ type: number; timestamp: number }>;
+  } catch (err) {
+    parseErr = err instanceof Error ? err.message : String(err);
+  }
+
+  if (parseErr !== null) {
+    mergedChecks.push({
+      name: 'A29.0b: rrweb/session.json parses as JSON',
+      expected: 'JSON.parse success',
+      actual: ``,
+      passed: false,
+    });
+    return {
+      passed: false,
+      name: pageResult.name,
+      checks: mergedChecks,
+      diagnostics: mergedDiagnostics,
+      error: pageResult.error,
+    };
+  }
+
+  const distinctTypes = [...new Set(events.map((e) => e.type))].sort((a, b) => a - b);
+  mergedDiagnostics.push(`A29 events.length=${events.length}`);
+  mergedDiagnostics.push(`A29 event types: ${distinctTypes.join(',')}`);
+
+  mergedChecks.push({
+    name: 'A29.2: rrweb/session.json contains > 0 events',
+    expected: '>0',
+    actual: events.length,
+    passed: events.length > 0,
+  });
+  mergedChecks.push({
+    name: `A29.3: rrweb emitted at least one Meta event (EventType.Meta=${EventType.Meta})`,
+    expected: 'has Meta',
+    actual: events.some((e) => e.type === EventType.Meta),
+    passed: events.some((e) => e.type === EventType.Meta),
+  });
+  mergedChecks.push({
+    name: `A29.4: rrweb emitted at least one FullSnapshot (EventType.FullSnapshot=${EventType.FullSnapshot})`,
+    expected: 'has FullSnapshot',
+    actual: events.some((e) => e.type === EventType.FullSnapshot),
+    passed: events.some((e) => e.type === EventType.FullSnapshot),
+  });
+  mergedChecks.push({
+    name: `A29.5: rrweb emitted at least one IncrementalSnapshot (EventType.IncrementalSnapshot=${EventType.IncrementalSnapshot})`,
+    expected: 'has IncrementalSnapshot',
+    actual: events.some((e) => e.type === EventType.IncrementalSnapshot),
+    passed: events.some((e) => e.type === EventType.IncrementalSnapshot),
+  });
+
+  const a29MergedPassed = mergedChecks.every((c) => c.passed);
+  return {
+    passed: a29MergedPassed,
+    name: pageResult.name,
+    checks: mergedChecks,
+    diagnostics: mergedDiagnostics,
+    error: pageResult.error,
+  };
+}

From dc57f5cfc03edc1a1416eb3726fcc1cb172b21d6 Mon Sep 17 00:00:00 2001
From: Mark 
Date: Wed, 20 May 2026 19:20:39 +0200
Subject: [PATCH 3/3] =?UTF-8?q?docs(03-01):=20complete=20A29=20rrweb=20DOM?=
 =?UTF-8?q?=20verification=20plan=20=E2=80=94=20SUMMARY?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- 2/2 plan tasks completed (c02914d + cc13f31).
- UAT harness 29 → 30 GREEN; vitest 171/171 preserved.
- Tier-1 FORBIDDEN_HOOK_STRINGS unchanged at 12.
- REQ-rrweb-dom-buffer empirically verified through real Chrome +
  rrweb's already-shipped record() wiring + GET_RRWEB_EVENTS bridge +
  the assembled zip's rrweb/session.json content.
- A29 events.length=4; event types {2, 3, 4} (Meta + FullSnapshot +
  IncrementalSnapshot — all 3 required surfaces empirically present).
- Worktree mode: STATE.md / ROADMAP.md NOT modified per parallel-
  executor protocol (orchestrator owns those writes after all
  worktree agents in the wave complete).
---
 .../03-01-SUMMARY.md                          | 227 ++++++++++++++++++
 1 file changed, 227 insertions(+)
 create mode 100644 .planning/phases/03-spec-10-smoke-verification-dom-event-log-verification/03-01-SUMMARY.md

diff --git a/.planning/phases/03-spec-10-smoke-verification-dom-event-log-verification/03-01-SUMMARY.md b/.planning/phases/03-spec-10-smoke-verification-dom-event-log-verification/03-01-SUMMARY.md
new file mode 100644
index 0000000..1b9a44d
--- /dev/null
+++ b/.planning/phases/03-spec-10-smoke-verification-dom-event-log-verification/03-01-SUMMARY.md
@@ -0,0 +1,227 @@
+---
+phase: 03-spec-10-smoke-verification-dom-event-log-verification
+plan: 01
+subsystem: testing
+tags:
+  - uat-harness
+  - a29
+  - rrweb
+  - dom-verification
+  - spec-10-4
+  - req-rrweb-dom-buffer
+  - approach-b
+  - probe-html
+  - eventtype-enum
+  - phase-3-wave-1
+
+requires:
+  - phase: 01-stabilize-video-pipeline
+    provides: "Plan 01-13 UAT harness Approach B (extension-internal page + synthetic MediaStream; page-side assertA* + host-side driveA* + harness.test.ts orchestrator); FORBIDDEN_HOOK_STRINGS lockstep pattern; pre-checkpoint bundle gates"
+  - phase: 02-stabilize-export-pipeline
+    provides: "Plan 02-04 A24-A28 harness extension (closest analog); findLatestZip helper at tests/uat/lib/harness-page-driver.ts; JSZip host-side parse pattern; chained-assertion / mtime-sort pattern; rrweb wiring + GET_RRWEB_EVENTS bridge production-shipped (src/content/index.ts:284-318)"
+
+provides:
+  - 1 new UAT harness assertion (A29) empirically verifying REQ-rrweb-dom-buffer + SPEC §10 #4 end-to-end through a real Chrome instance against synthetic probe HTML (form + table + modal + DOM-mutation trigger)
+  - assertA29 page-side orchestrator (DOM mutation dispatch + setupFreshRecording + SAVE) at tests/uat/extension-page-harness.ts
+  - driveA29 host-side 3-phase driver (page.evaluate + findLatestZip + JSZip rrweb/session.json + EventType-enum grep) at tests/uat/lib/harness-page-driver.ts
+  - Probe HTML in tests/uat/extension-page-harness.html (form with text+email+password+submit; table with thead+2 rows; modal trigger button with hidden modal div) appended BELOW existing scaffold; head + tokens.css link preserved
+  - EventType import `import { EventType } from '@rrweb/types';` (already transitively present; first explicit use)
+  - Orchestrator extension: drivers array 28 → 29; total 30/30 with A0; banner mentions A29
+
+affects:
+  - phase-03 plans 02/03/04/05 (will follow same Approach B template + can chain off A29 if needed)
+  - phase-04 future rrweb v2 upgrade (A29's EventType enum import surface needs migration validation if @rrweb/types relocates NodeType per RESEARCH §"State of the Art")
+
+tech-stack:
+  added:
+    - "@rrweb/types EventType enum (explicit import in tests/uat/lib/harness-page-driver.ts; transitively present via rrweb 2.0.0-alpha.4 since Phase 1)"
+  patterns:
+    - "Approach B harness extension (Plan 02-04 verbatim template): page-side assertXX + host-side driveXX 3-phase (page.evaluate → findLatestZip → JSZip parse + grep) — proven on driveA26 (meta.json) + driveA28 (zip-layout); reused verbatim for driveA29 (rrweb/session.json)"
+    - "RESEARCH Pitfall 1 mitigation pattern: synthetic probe HTML + pre-SAVE DOM mutation dispatch (input.value + dispatchEvent + modal click) ensures rrweb emits IncrementalSnapshot in addition to Meta + FullSnapshot — empirically verified A29.5 GREEN with events.length=4 + event types {2,3,4}"
+    - "Page-side orchestrator (NOT stub) — assertA29 dispatches DOM mutation + setupFreshRecording + SAVE because the mutation MUST land BEFORE the GET_RRWEB_EVENTS bridge pulls the buffer; chaining off A28's already-completed zip would miss the IncrementalSnapshot window per Pitfall 1"
+
+key-files:
+  modified:
+    - tests/uat/extension-page-harness.html (probe HTML: form#probe-form + table#probe-table + button#probe-modal-trigger + div#probe-modal — appended BELOW existing `
` scaffold; head + tokens.css link preserved; no