# Progress Log — challenger_m4_2

Last visited: 2026-10-02T04:26:00Z

## Status
Empirical adversarial challenge of Milestone M4 (30 Biomes & Graphics Overhaul) complete. All tests and invariant stress suites PASSED with 100% empirical verification. Verdict: APPROVE.

## Steps
- [x] Step 1: Record dispatch in DISPATCH.md and update BRIEFING.md
- [x] Step 2: Run pytest suite (379 tests across 7 test files) -> 379/379 PASSED in 9.95s
- [x] Step 3: Run Node.js unit and stress suites:
  - `node tests/unit/test_biome_texture_manager.js` -> 8/8 sections PASSED
  - `node tests/security_fuzzing/test_challenger_biome_texture_stress.js` -> 4/4 suites PASSED
  - `node tests/security_fuzzing/test_challenger_lru_thrashing_stress.js` -> 4/4 suites PASSED (0 leaks, 16.01 MB)
  - `node tests/security_fuzzing/test_challenger_tile_grid_stress.js` -> 48/48 tests PASSED
- [x] Step 4: Empirically stress-test memory invariants via `tests/unit/test_challenger_m4_2_empirical_invariants.js`:
  - 8-slot LRU OffscreenCanvas bounds strictly verified under 1,500 intense camera pan passes (0 leaks)
  - Memory ceiling <= 16.5 MB verified across 1,200 rapid zone and biome switches (measured: 16.000 MB - 16.010 MB)
  - Graceful fallback for 30 adversarial/non-existent biomes across 840 tile fallback combinations (0 exceptions, 0 crashes)
- [x] Step 5: Run hygiene check `python tools/lint/check_code_and_doc_hygiene.py --strict` -> 0 Hard Cap violations
- [ ] Step 6: Update BRIEFING.md with empirical findings
- [ ] Step 7: Write handoff.md with explicit verdict (APPROVE)
- [ ] Step 8: Send completion message to parent