# BRIEFING — 2026-10-01T22:34:00Z

## Mission
Implement Milestone M5: Encounter Zone Architecture & Terrain-Anchored Spawning (Procedural PoE2 Encounter Ecosystem).

## 🔒 My Identity
- Archetype: worker
- Roles: implementer, qa, specialist
- Working directory: c:\Projects\FreeExile\.agents\teamwork\worker_m5_1
- Original parent: 1cc48fc5-ce57-4f48-8964-24cab4bfcacc
- Milestone: M5 Encounter Zone Architecture

## 🔒 Key Constraints
- DO NOT CHEAT. All implementations must be genuine. No dummy or facade code.
- File length limits:
  - `grid_pathfinder.js`: strictly <= 320 lines (Soft 350, Hard 500)
  - `wilderness_zone_packs.js`: strictly <= 350 lines (PRESERVE pack_tang_kiem_alpha and pack_tang_kiem_beta)
  - `monster_pack_system.js`: strictly <= 350 lines
  - `ambush_trigger_system.js`: strictly <= 300 lines
  - `monster_system.js`: strictly <= 480 lines (HARD CEILING <= 490 lines verified by unit tests)
  - `boss_gate_controller.js`: strictly <= 200 lines
  - `world_renderer.js`: strictly <= 490 lines (Hard cap 500 lines)
  - `index.html`: strictly <= 200 lines (Soft cap 200, Hard cap 400 lines)
  - `tests/unit/test_encounter_zones.py`: strictly <= 300 lines
- Verification suites:
  - pytest tests/unit/test_encounter_zones.py -v
  - pytest tests/unit/test_fog_and_minimap.py -v (14/14 PASS)
  - pytest tests/unit/test_tile_collision.py -v (11/11 PASS)
  - pytest tests/unit/test_mobile_webapp_config.py -v (15/15 PASS)
  - pytest tests/unit/test_monster_poise_and_leash.py -v (PASS <= 490 lines)
  - pytest tests/unit/test_waypoint_safe_radius.py -v (PASS <= 490 lines)
  - pytest tests/e2e/test_poe2_map_system_e2e.py -v (81/81 PASS)
  - node tools/perf/map_render_benchmark.js (PASS 0 re-bakes)
  - pytest tests/unit/ -q (all pass)
  - python tools/lint/check_code_and_doc_hygiene.py --strict (0 violations)

## Current Parent
- Conversation ID: 1cc48fc5-ce57-4f48-8964-24cab4bfcacc
- Updated: 2026-10-01T22:34:00Z

## Task Summary
- **What to build**: Full procedural M5 encounter architecture: Zero-heap grid pathfinder with DDA raycasting, terrain-anchored monster pack spawning and cohesive leashing, scripted POI wave ambushes with dual visual cues, boss gate proximity lore popup & auto-unlock via `zoneEncounterProgress`, and comprehensive unit tests.
- **Success criteria**: All tests pass, strict file length ceilings met, zero regressions across test suite.
- **Interface contracts**: c:\Projects\FreeExile\.agents\teamwork\orchestrator_11\PROJECT.md
- **Code layout**: c:\Projects\FreeExile\.agents\teamwork\orchestrator_11\PROJECT.md

## Key Decisions Made
- Modular delegation pattern: kept `monster_system.js` at 476 lines (<490 limit) by delegating cluster generation, pack leashing, and kill reporting to `monster_pack_system.js` and obstacle-aware chase steering to `grid_pathfinder.js`.
- Supercover DDA raycaster in `grid_pathfinder.js` with corner-cutting prevention and infinite tMax guard on zero-delta axes.
- Maintained exact backward compatibility with `wilderness_zone_packs.js` pack keys `pack_tang_kiem_alpha` & `pack_tang_kiem_beta`.
- Author hybrid Python/Node.js unit test suite in `tests/unit/test_encounter_zones.py` executing genuine JS code with zero mocking shortcuts.

## Artifact Index
- `.agents/teamwork/worker_m5_1/BRIEFING.md` — Agent working memory
- `.agents/teamwork/worker_m5_1/progress.md` — Heartbeat and task progress
- `.agents/teamwork/worker_m5_1/handoff.md` — 5-component handoff report

## Change Tracker
- **Files modified**:
  - `client/webapp/js/engine/grid_pathfinder.js`: Zero-heap static buffer A* pathfinder & DDA raycaster (300 lines)
  - `client/webapp/js/data/wilderness_zone_packs.js`: Encounter archetypes and terrain pack generator (298 lines)
  - `client/webapp/js/engine/monster_pack_system.js`: Terrain-anchored cluster spawning, leashing, progress tracking (277 lines)
  - `client/webapp/js/engine/ambush_trigger_system.js`: Scripted POI wave ambushes with visual/audio effects (143 lines)
  - `client/webapp/js/engine/monster_system.js`: Hooked obstacle-aware chase, pack leashing, kill reporting (476 lines)
  - `client/webapp/js/engine/boss_gate_controller.js`: Auto-unlock on zone clear, proximity lore popup & hysteresis (197 lines)
  - `client/webapp/js/engine/world_renderer.js`: POI aura/rune/beacon rendering with FoW awareness (475 lines)
  - `client/webapp/index.html`: Mounted grid_pathfinder.js before monster_system.js (198 lines)
  - `tests/unit/test_encounter_zones.py`: 12 genuine unit tests (6 server + 6 Node.js runtime) (259 lines)
- **Build status**: All 1055 unit tests passed (exit 0)
- **Pending issues**: None

## Quality Status
- **Build/test result**: PASS (1055/1055 passed in 95.86s, 81/81 e2e passed, map benchmark approved)
- **Lint status**: 0 hard cap violations across all modified M5 files
- **Tests added/modified**: 12 new tests in `tests/unit/test_encounter_zones.py`