# BRIEFING — 2026-10-09T09:03:00Z

## Mission
Adversarially probe and empirically verify Milestone M4 Iteration 2 remediation: Character asset invariants, turnaround sheets, legacy archive, episode assembly probe, and M2/M4 test suites.

## 🔒 My Identity
- Archetype: challenger
- Roles: critic, specialist
- Working directory: c:\Projects\KieuStory\.agents\teamwork\challenger_m4_iter2_2
- Original parent: 97faf5e5-a830-491c-b78c-2af12175badf
- Milestone: M4 Iteration 2 Gate Verification
- Instance: 2 of 2

## 🔒 Key Constraints
- Review-only — do NOT modify implementation code
- Empirical verification mandatory — must write and execute tests directly
- No unverified claims — if cannot reproduce empirically, does not count
- Do not trust worker's claims or logs without independent execution

## Current Parent
- Conversation ID: 97faf5e5-a830-491c-b78c-2af12175badf
- Updated: 2026-10-09T08:56:00Z

## Review Scope
- **Files to review**: `04_Assets/characters/`, `04_Assets/turnaround_sheets/`, `04_Assets/archive/ep01_legacy_v1/`, `05_Production_Pipeline/production_orchestrator.py`, `tests/test_m2_hygiene.py`, `tests/test_production_pipeline_m4.py`
- **Interface contracts**: `c:\Projects\KieuStory\.agents\teamwork\orchestrator_1\PROJECT.md`, `c:\Projects\KieuStory\.agents\teamwork\ORIGINAL_REQUEST.md`
- **Review criteria**: Character asset invariants (exactly 62 files, git clean, core portraits valid), turnaround sheets (55 files), legacy archive (184 video files), episode assembly probe, M2 hygiene test suite (6/6), M4 pipeline test suite (16/16).

## Key Decisions Made
- Executed empirical tests using Python scripts, CLI commands, and authored `tests/test_challenger2_m4_empirical_probe.py` (10/10 PASS).
- Verified zero git diff and zero untracked files in `04_Assets/characters/`.
- Tested PIL loading across all 62 character files and all 55 turnaround sheet files.
- Verified end-to-end simulated episode assembly with EBU R128 loudness normalization.
- Issued verdict: APPROVE Milestone M4 Iteration 2 Gate.

## Artifact Index
- `BRIEFING.md` — persistent working memory
- `progress.md` — liveness heartbeat
- `tests/test_challenger2_m4_empirical_probe.py` — empirical test harness (10/10 PASS)
- `handoff.md` — final 5-component challenge verdict

## Attack Surface
- **Hypotheses tested**:
  * Hypothesis 1: `04_Assets/characters/` might contain leftover untracked or modified files -> FALSE (exact count 62, git status strictly clean).
  * Hypothesis 2: 14 core character portraits might have altered file sizes or formats -> FALSE (all >500kB, valid PNG, exact resolutions).
  * Hypothesis 3: 55 turnaround sheets might contain corrupt or 0-byte images -> FALSE (all 55 files >0 bytes, valid PNGs).
  * Hypothesis 4: Legacy archive might be missing videos or legal metadata -> FALSE (exactly 184 .mp4 files + README.md > 1000 bytes with required legal citations).
  * Hypothesis 5: Episode assembly `--check` or `--dry-run` might crash on missing scenes -> FALSE (clean status report, zero exception).
  * Hypothesis 6: Episode assembly with simulated masters might fail FFmpeg concat or EBU R128 normalization -> FALSE (simulated 3-scene assembly created valid AAC 48kHz stereo master).
- **Vulnerabilities found**: None. All invariants hold rigorously.
- **Untested angles**: Live multi-worker distributed GPU rendering of remaining episodes (ep02-ep06), which is scheduled for future production phases beyond M4.

## Loaded Skills
- None