# BRIEFING — 2026-10-01T00:55:00Z

## Mission
Analyze the exact database schema and migration strategy for `progression_benchmarks` in `data/game_design_matrix.db` and `server/world/game_design_matrix_schema.py`.

## 🔒 My Identity
- Archetype: explorer
- Roles: teamwork_preview_explorer
- Working directory: c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2
- Original parent: 6f4a2aa2-4315-4660-8cb7-8352a7220c95
- Milestone: M1 Database Schema & Migration Strategy for progression_benchmarks

## 🔒 Key Constraints
- Read-only investigation — do NOT implement / do NOT modify source code
- High information density, precise filepaths and line numbers
- Provide exact SQL migration and DDL changes for Worker M1

## Current Parent
- Conversation ID: 6f4a2aa2-4315-4660-8cb7-8352a7220c95
- Updated: not yet

## Investigation State
- **Explored paths**:
  - `server/world/game_design_matrix_schema.py`
  - `server/world/game_design_matrix_types.py`
  - `server/world/game_design_matrix_service.py`
  - `server/world/game_design_matrix_seeder.py`
  - `data/game_design_matrix.db`
  - `tests/unit/test_game_design_matrix.py`
  - `tools/lint/verify_game_design_matrix.py`
  - `spec_miner_survey_exp_1/report.md` & `handoff.md`
- **Key findings**:
  - Extended 13-column schema specified with strict SQLite CHECK constraints.
  - Monotonicity and backwards compatibility guaranteed by setting `target_exp = cumulative_exp`.
  - Automated migration helper designed for `GameDesignMatrixService._init_database()` to overcome SQLite `CREATE TABLE IF NOT EXISTS` no-op limitation.
  - Complete drop-in code provided for Worker M1 for all 4 target files plus SQL migration script.
- **Unexplored areas**: None for M1 schema and migration scope.

## Key Decisions Made
- Confirmed `target_exp` must equal `cumulative_exp` to preserve 100% backwards compatibility with `validate_game_design_integrity()` and existing lookups.
- Designed two-tier migration: automatic schema evolution inside `GameDesignMatrixService` and standalone script `migrations/001_extend_progression_benchmarks.sql`.
- Completed `report.md` and `handoff.md`.

## Artifact Index
- `c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2\DISPATCH.md` — Dispatch log
- `c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2\BRIEFING.md` — Persistent working memory
- `c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2\progress.md` — Heartbeat tracking
- `c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2\report.md` — Analysis report (Complete)
- `c:\Projects\FreeExile\.agents\teamwork\explorer_m1_progression_2\handoff.md` — Handoff report (Complete)