# BRIEFING — 2026-10-04T03:52:00Z

## Mission
Independent quality and adversarial review of Milestone 1 (3D Dimensions & Billboard Annotations in app/static/bim/index.html).

## 🔒 My Identity
- Archetype: reviewer_critic
- Roles: reviewer, critic
- Working directory: c:\Projects\DSCons\.agents\teamwork\teamwork_preview_reviewer_m1_1
- Original parent: befbfc73-5853-4a94-b280-61f27b35aa73
- Milestone: Milestone 1 (3D Dimensions & Billboard Annotations)
- Instance: 1 of 1

## 🔒 Key Constraints
- Review-only — do NOT modify implementation code
- Actively check for integrity violations (hardcoded test results, facade implementations, shortcuts, fabricated verification)
- Verify correctness of 21 dimensions against 28 construction drawings
- Verify WebGL canvas billboard sprite implementation (offscreen 2D canvas DPR=2, depthTest: false, MediaRecorder compatibility)
- Verify UI toggle (#chkDimensions, #btnDims)
- Run regression tests and Check 4 E2E test

## Current Parent
- Conversation ID: befbfc73-5853-4a94-b280-61f27b35aa73
- Updated: 2026-10-04T03:52:00Z

## Review Scope
- **Files to review**: app/static/bim/index.html
- **Interface contracts**: .agents/teamwork/ORIGINAL_REQUEST.md, .agents/teamwork/teamwork_preview_orchestrator_1/PROJECT.md, .agents/teamwork/teamwork_preview_worker_m1_1/handoff.md
- **Review criteria**: Correctness of dimensions, WebGL billboard sprite architecture, zero-DOM-overlay for video export, clean UI toggling, test passing, no regressions.

## Review Checklist
- **Items reviewed**:
  - `app/static/bim/index.html`: lines 140, 171-174, 435, 450, 813-1284, 1323-1357
  - 21 3D dimensions and billboard text sprites
  - Canvas supersampling DPR=2, `depthTest: false`, `renderOrder: 999`
  - Dual UI toggles `#chkDimensions` and `#btnDims`
  - Playwright E2E test Check 4
  - Architecture boundary regression test suite
- **Verdict**: APPROVE
- **Unverified claims**: None. All 21 dimensions verified with live WebGL scene graph inspection.

## Attack Surface
- **Hypotheses tested**:
  - H1: State desynchronization between `#chkDimensions` and `#btnDims` -> PASSED (strict invariant `chk == btnActive == visible` held across all sequence permutations).
  - H2: NaN / degenerate geometry in dimension lines or tick vectors -> PASSED (0 NaNs, 20 valid BufferGeometry line segments).
  - H3: Camera rotation or preset view switches causing sprite distortion or matrix exceptions -> PASSED (0 console errors across all 6 presets).
  - H4: Synthetic/mock facade or hardcoded bypasses -> PASSED (genuine Three.js line segments, mathematical tick generation, dynamic canvas rasterization).
- **Vulnerabilities found**: None.
- **Untested angles**: Milestone 2 4D Player, Milestone 3 Site Diary, Milestone 4 Video Export (out of scope for M1).

## Key Decisions Made
- Confirmed zero integrity violations.
- Verified all 21 dimensions match drawing specs verbatim.
- Issued verdict APPROVE for Milestone 1.

## Artifact Index
- DISPATCH.md — Parent dispatch instructions
- BRIEFING.md — Working memory and situational awareness
- progress.md — Liveness heartbeat
- test_adversarial_m1.py — Independent adversarial stress test script
- handoff.md — Final review, adversarial challenge, and handoff report