# BRIEFING — 2026-10-09T08:39:55Z

## Mission
Investigate and formulate the exact remediation strategy for Milestone M4 Iteration 2 addressing Defect 1 (Character assets invariant violation) and Defect 2 (Fallback concat string-replacement bug).

## 🔒 My Identity
- Archetype: explorer
- Roles: Explorer, Forensic Remediation Investigator, Synthesis
- Working directory: c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1
- Original parent: 97faf5e5-a830-491c-b78c-2af12175badf
- Milestone: Milestone M4 Iteration 2 (Remediation Strategy)

## 🔒 Key Constraints
- Read-only investigation — do NOT implement production changes directly
- Write only to your folder (.agents/teamwork/explorer_m4_remediation_1); read any folder
- Never place source code, tests, or data files in .agents/teamwork/
- All findings must be backed by direct empirical observations with line numbers and exact paths

## Current Parent
- Conversation ID: 97faf5e5-a830-491c-b78c-2af12175badf
- Updated: not yet

## Investigation State
- **Explored paths**:
  - `DISPATCH.md`, `ORIGINAL_REQUEST.md`, `orchestrator_1/PROJECT.md`
  - `auditor_m4_1/handoff.md`, `challenger_m4_1/handoff.md`, `reviewer_m4_2/handoff.md`
  - `04_Assets/characters/` (entire tree), `tests/test_m2_hygiene.py`, `tests/test_adversarial_m4_audio_concat_probe.py`, `tests/test_production_pipeline_m4.py`
  - `05_Production_Pipeline/production_orchestrator.py` (lines 106, 1165-1200)
  - `05_Production_Pipeline/audio_continuity_engine.py` (lines 45-70)
  - `tools/update_banana_turnaround_prompts.py`, `tools/manage_turnaround_sheets.py`, `02_AI_Prompts/gemini_banana_prompts.json`
- **Key findings**:
  - Defect 1: `04_Assets/characters/` has 117 physical files: 62 Git-tracked canonical files + 55 untracked files (54 turnaround sheets across 7 subfolders + 1 cropped view artifact). All 14 core portraits are 100% undamaged and intact. Generation source was `tools/update_banana_turnaround_prompts.py` and `tools/manage_turnaround_sheets.py`. Generation has completed; no active process is running. Relocating these 55 files to `04_Assets/turnaround_sheets/` restores the 62-file invariant, causing `test_m2_hygiene.py` to pass 6/6 cleanly.
  - Defect 2: Line 1170 of `production_orchestrator.py` used `ffmpeg_exe.replace("ffmpeg", "ffprobe")`, which corrupted Windows WinGet paths by replacing folder name `ffmpeg-9.0.2-full_build`. Silently catching `FileNotFoundError` caused audio-less clips (`-an`) to crash FFmpeg with `Stream specifier ':a' ... matches no streams`. Importing `get_ffprobe` from `audio_continuity_engine` and replacing line 1170 with `ffprobe_exe = get_ffprobe()` eliminates the crash and correctly triggers `aevalsrc=0` silence fallback.
- **Unexplored areas**: None. All objectives fully investigated and verified.

## Key Decisions Made
- Relocate all 55 untracked files to `04_Assets/turnaround_sheets/` preserving folder hierarchy, rather than deleting them, preserving creative assets.
- Update tools `update_banana_turnaround_prompts.py` and `manage_turnaround_sheets.py` to reference `04_Assets/turnaround_sheets/` to prevent future re-pollution.
- Deliver exact code diffs and step-by-step instructions in `remediation_plan.md` and `handoff.md` for Worker 2 execution.

## Artifact Index
- `c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\DISPATCH.md` — Inbound dispatch requirements
- `c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\BRIEFING.md` — Persistent memory
- `c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\progress.md` — Liveness heartbeat
- `c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\remediation_plan.md` — Actionable execution guide for Worker 2
- `c:\Projects\KieuStory\.agents\teamwork\explorer_m4_remediation_1\handoff.md` — 5-component handoff report