---
description: Networking protocol compatibility and documentation rules
alwaysApply: true
---

# Protocol Rules

When modifying the networking protocol:
- Update protocol documentation whenever packet structure changes.
- Treat new fields as optional on receive unless the change is intentionally breaking.
- Use safe defaults when a field is missing.
- Do not rename protocol fields unless specifically requested.
- Preserve unknown JSON fields where possible.

Preserve existing field names, including:
- `type`
- `playerId`
- `x`, `y`, `z`
- `angleZ`
- `cellId`
- `worldspaceId`
- `movementType`
- `clientTime`
- `serverTime`
- `isMoving`
- `movementSpeed`
- `isSprinting`
- `isSneaking`
- `isJumping`
- `weaponDrawn`

When adding a new protocol field, make sure:
- The plugin sends it when appropriate.
- Receivers parse it safely and tolerate it being absent.
- The server preserves or relays it.
- `server/fake_client.py` is updated if useful for testing.
- Relevant protocol documentation is updated.

Protocol changes should avoid breaking already-working transform sync unless the requested change explicitly requires it.