# V5 Crossplay and Cross-Progression Integration

The launch policy lives at `V5/crossplay/crossplay-progression-policy.json`. It
is validated by `V5/tools/crossplay/validate-crossplay.py` and wired into the
Auth, Matchmaking, Companion App Bridge, and Mind Palace Cloud Sync service
contracts.

## Surfaces

- Auth owns the canonical `v5acct` account id and per-platform credential
  ledger.
- Companion App Bridge owns cross-progression snapshots for profile, cosmetics,
  Bureau XP, and Mind Palace read models.
- Matchmaking owns per-cell crossplay pool selection and the Sci-Fi spaceship
  PvP opt-out path.
- Companion App Bridge owns signed save export/import bundles.
- Mind Palace Cloud Sync owns graph conflict policy: last writer wins for nodes,
  append-only for accusations.

## Verification

Run the focused gate from the repository root:

```bash
python3 V5/tools/crossplay/validate-crossplay.py
pytest -q V5/tools/test_validate_crossplay.py
pnpm --filter @v5/service-shared --filter @v5/service-auth --filter @v5/service-matchmaking --filter @v5/service-companion-app-bridge --filter @v5/service-mindpalace-cloud-sync run test
```