# Progress: Challenger M2 Fix 1

Last visited: 2026-10-01T20:51:00Z

## Current Status: Empirical Stress Tests Complete - Verdict: APPROVE

- [x] Received dispatch instructions and reviewed `ORIGINAL_REQUEST.md` (R2) & `worker_m2_fix_1/handoff.md`.
- [x] Initialized `BRIEFING.md` and `DISPATCH.md`.
- [x] Inspect implementation of `tile_map_renderer.js` and benchmark harnesses.
- [x] Run benchmark verification suites:
  - `node tools/perf/map_render_benchmark.js` -> ✅ PASS
  - `node tools/perf/stress_test_lru_cache.js` -> ✅ PASS
  - `pytest tests/e2e/test_poe2_map_system_e2e.py -v` -> ✅ PASS (81 passed)
- [x] Implement independent adversarial test script `tests/unit/test_challenger_lru_thrashing_stress.js` to independently verify:
  - Stationary at (30, 30): exactly 0 re-bakes over 50 static frames.
  - Stationary at (50, 50): exactly 0 re-bakes over 50 static frames.
  - Stationary at (10, 10), (60, 45), (0, 0), (119, 89): all 0 re-bakes.
  - 10,000 rapid pan frames stress with dynamic `markChunkDirty`: 0 leaked canvases, 5.22 avg blits, 8 max blits, FPS > 300,000.
  - Simultaneous multi-chunk dirty invalidation and re-stabilization: PASS.
  - Boundary and viewport edge cases (NaN, OOB, 0x0, landscape): PASS.
- [x] Run hygiene check (`python tools/lint/check_code_and_doc_hygiene.py --strict`): 0 hard cap violations.
- [x] Write `handoff.md` with explicit APPROVE verdict.
- [ ] Send coordination message back to parent.