# Progress — Challenger M5 Fix 2

**Agent**: `challenger_m5_fix_2`
**Last visited**: 2026-10-01T22:59:00Z

## Plan
1. [x] Step 1: Initialize BRIEFING.md and progress.md.
2. [x] Step 2: Inspect implementation of remediated files (`ambush_trigger_system.js`, `monster_pack_system.js`, `grid_pathfinder.js`, etc.).
3. [x] Step 3: Run existing unit test suites and benchmarks specified in dispatch:
   - `pytest tests/unit/test_encounter_zones.py -v` (16/16 passed in 1.43s)
   - `pytest tests/unit/test_waypoint_safe_radius.py -v` (17/17 passed)
   - `pytest tests/unit/test_monster_poise_and_leash.py -v` (10/10 passed)
   - `pytest tests/unit/test_fog_and_minimap.py -v` (14/14 passed)
   - `pytest tests/unit/test_tile_collision.py -v` (11/11 passed)
   - `pytest tests/e2e/test_poe2_map_system_e2e.py -v` (81/81 passed in 1.11s)
   - `node tools/perf/map_render_benchmark.js` (PASS with 0 stationary re-bakes, 147k FPS)
   - `node --expose-gc tools/perf/stress_test_grid_pathfinder.js` (PASS with 0 GC thrashing, 0 LoS false positives)
4. [x] Step 4: Write and execute empirical stress test harness for Item 1: Ambush Minion Wall Fallback (randomized tests on POIs placed in 1-tile wide dead-ends and against walls, verify 0 minions spawn in blocked tiles) -> Created `tests/unit/test_challenger_m5_fix_2_stress.js`, tested 100 extreme dead-end layouts, 401 minions spawned, 0 in blocked tiles, 0 out-of-bounds.
5. [x] Step 5: Write and execute empirical stress test harness for Item 2: Pack Clear Idempotency (simulate 100 rapid AoE pack clears, verify `zoneEncounterProgress` strictly preserves `clearedPacks <= totalPacks`) -> Tested 100 rapid AoE trials with chaotic shuffled duplicate bursts, 0 invariant violations, exactly 1 boss gate unlock per completed zone.
6. [x] Step 6: Run full unit test suite `pytest tests/unit/ -q` (1220/1220 passed in 154.25s) and `python tools/lint/check_code_and_doc_hygiene.py --strict` (0 hard cap violations).
7. [x] Step 7: Update BRIEFING.md, write `handoff.md` with explicit verdict (`APPROVE`), and send completion message to parent.