Design the team logic for a team-based multiplayer mode in Unreal Engine — two or more teams, friendly fire disabled within a team, per-team score, and team-colored nameplates. The server must assign and balance teams; a client must never be able to decide on its own who is an ally or report kills it considers valid. Every client needs to read every player's team so it can color nameplates and run friend/foe checks, so each player's team affiliation must be visible to all clients. A player's team must survive their character dying and respawning, and survive a disconnect/rejoin so they return to the same side. Describe where you store team affiliation and per-team score, who assigns teams, how friend/foe and friendly-fire are resolved, and the trade-offs of your approach.

Key classes

• AGameMode — server-only: assigns TeamId, balances rosters, enforces rules.
• AGameState — replicated to everyone: team scores, match phase, round timer.
• APlayerState — per player: a replicated TeamId, stats, name.
• IGenericTeamAgentInterface — UE's standard interface to query an FGenericTeamId from a Pawn/Controller.

Data model

TeamId lives on PlayerState because PlayerState outlives Pawn respawns and is visible to every client. GameState holds team aggregates. Assignment and balance are solely the GameMode's responsibility.

Data flow

1. A player connects → GameMode assigns a TeamId (balanced by team size).
2. The TeamId is written to PlayerState and replicated to all clients.
3. A damage event → the server compares instigator and target TeamId; friendly fire is blocked by rule.
4. An objective is captured → the server adds points on GameState.
5. Clients read replicated TeamIds and score for nameplate colors and the scoreboard.

Replication considerations

TeamId on PlayerState is Replicated, so it is visible to everyone for coloring and checks. Friend/foe decisions are made only by the server. GameState replicates the score; GameMode exists only on the server and never replicates. Team chat is filtered on the server by recipients' TeamId.

Designer-facing config

Team count, size, balance rules, and friendly fire are DataAsset fields or GameMode config. Team colors are a DataTable. Spawn points are tagged by team.

Trade-offs

• TeamId on PlayerState vs. on Pawn: on PlayerState it survives death and rejoin; on Pawn it is lost on respawn.
• UE's GenericTeamId vs. a custom system: the standard integrates with AI perception but is less flexible for complex alliances.