# BRIEFING — 2026-10-01T20:23:00Z

## Mission
Empirically challenge M2 Visual Systems (`tile_map_renderer.js`, `world_renderer.js`) and Non-Regression (TileTypes 0-19 palettes/elevation, waypoint safe radius, map device, 935 unit tests, strict hygiene).

## 🔒 My Identity
- Archetype: empirical-challenger
- Roles: critic, specialist
- Working directory: c:\Projects\FreeExile\.agents\teamwork\challenger_m2_2
- Original parent: 1cc48fc5-ce57-4f48-8964-24cab4bfcacc
- Milestone: M2 Visual & Non-Regression
- Instance: 2 of 2

## 🔒 Key Constraints
- Review-only — do NOT modify implementation code
- Report failures as findings — do not fix them yourself
- Empirically verify claims with executable tests and harnesses
- .agents/teamwork/ holds ONLY metadata

## Current Parent
- Conversation ID: 1cc48fc5-ce57-4f48-8964-24cab4bfcacc
- Updated: 2026-10-01T20:23:00Z

## Review Scope
- **Files reviewed**:
  - `client/webapp/js/engine/world_renderer.js` (452 lines)
  - `client/webapp/js/engine/tile_map_renderer.js` (279 lines)
  - `tools/perf/map_render_benchmark.js` (154 lines)
  - `tools/verification/verify_m2_visual_rendering.js` (16 test cases)
  - `tests/unit/test_waypoint_safe_radius.py` (17 tests)
  - Full unit test suite `tests/unit/` (935 tests)
  - E2E test suite `tests/e2e/test_poe2_map_system_e2e.py` (81 tests)
  - Hygiene auditor `tools/lint/check_code_and_doc_hygiene.py --strict`
- **Interface contracts**:
  - `ORIGINAL_REQUEST.md` (section ## 2026-10-01T19:19:13Z - R2)
  - `orchestrator_11/PROJECT.md`
- **Review criteria**:
  - All 20 TileTypes (0-19) in `TILE_PALETTES` have distinct colors and 2.5D elevation extrusion
  - `pytest tests/unit/test_waypoint_safe_radius.py -v` (17 passed)
  - Interactive systems in `world_renderer.js`: waypoint safe radius ring, PoE2 6-Portal Map Device, World Gate, Quest Gate, Ground Drops
  - Full test suite: `pytest tests/unit/ -q` (935 passed, 0 regressions)
  - Code hygiene: `python tools/lint/check_code_and_doc_hygiene.py --strict` (0 hard cap violations)

## Attack Surface
- **Hypotheses tested**:
  1. Are all 20 TileTypes (0-19) defined with distinct colors and appropriate 2.5D elevation extrusion? (Verified: 20/20 distinct signatures, correct elevations for walls, barricades, debris, boss gate, altars, and sunken depressions).
  2. Does `_drawTile` properly render 2.5D extrusion geometry and special runes without clipping or NaN? (Verified: 2 side wall fills for elev>0, correct elevation offset `py - elev`, boss gate seal rune, POI marker dot, biome tint overrides).
  3. Does chunk baking maintain isometric painter's order? (Verified: non-decreasing u+v order 0 to 30 ensures front tiles occlude back tiles).
  4. Does `TileMapRenderer` memory exceed 8 MB on mobile? (Verified: 4-slot LRU OffscreenCanvas pool consumes exactly 8.01 MB for 120x90 grid).
  5. Does `world_renderer.js` regress on Waypoint Safe Radius, PoE2 6-Portal Map Device, World Gate, Quest Gate, or Ground Drops? (Verified: 100% intact, all exact string checks passed).
  6. Does full test suite pass with zero regressions? (Verified: 935/935 unit tests pass, 81/81 E2E tests pass, 0 hygiene hard cap violations).
- **Vulnerabilities found**: None. The implementation is robust, adheres to memory caps, and maintains backward compatibility.
- **Untested angles**: Native mobile WebGL/Metal shader acceleration (outside M2 OffscreenCanvas scope).

## Loaded Skills
- None

## Key Decisions Made
- All empirical verification gates passed with zero regressions.
- Issuing explicit verdict: **APPROVE**.

## Artifact Index
- DISPATCH.md — Current dispatch instruction
- BRIEFING.md — Situational awareness
- progress.md — Liveness heartbeat
- tools/verification/verify_m2_visual_rendering.js — Executable empirical verification suite
- handoff.md — Final verdict report