---

name: "@tank/party-game-dev" description: | Build real-time multiplayer party games (Jackbox-style) with full-stack TypeScript. Covers host-player architecture (TV + phones), VIP role (player with elevated control), Socket.IO networking, game state machines, room/lobby management, voting and scoring systems, content safety (profanity filtering, family mode, VIP censoring), and BDD testing with multiple browser contexts. Synthesizes patterns from Jackbox Games, Drawphone, Rocketcrab, Fishbowl, Socket.IO docs, and Playwright multi-context testing.

Trigger phrases: "party game", "jackbox", "multiplayer game", "real-time game", "game room", "lobby system", "room code", "socket.io game", "websocket game", "game state machine", "voting game", "drawing game", "trivia game", "quiplash", "drawful", "host screen", "player controller", "VIP", "game VIP", "room owner", "kick player", "ban player", "multiplayer testing", "game server", "party game backend", "prompt and response game", "audience voting", "game lobby", "turn-based multiplayer", "phone controller game", "content moderation", "profanity filter", "family friendly", "test multiplayer", "BDD game testing"

Party Game Development

Build Jackbox-style party games: one shared screen (TV/projector) runs the host display, each player uses their phone as a controller. The first player to join becomes the VIP — a player with elevated control (start game, kick players, censor content). The VIP is NOT the host. The host is the TV. All connected via WebSockets with server-authoritative state.

Core Philosophy

1. Server owns the truth — All game state lives on the server. Clients send inputs, server validates, broadcasts results. No cheating possible.
2. Rooms are ephemeral — In-memory state, 4-character room codes, auto-cleanup. No database needed for the game itself.
3. Phones are dumb controllers — Player devices submit inputs and render state. Zero game logic on the client.
4. VIP controls the game — First player to join gets elevated privileges (start, kick, censor, settings). Transfers automatically on disconnect.
5. Test with real players — BDD tests spawn multiple browser contexts. No mocks. Real WebSocket connections. Real game flow.
6. Ship the simplest game first — Prompt-response (Quiplash pattern) is the easiest to build. Start there, add complexity later.

Quick-Start

"I want to build a party game from scratch"

Step	Action	Reference
1	Choose game type (prompt-response recommended for first game)	references/game-types-and-mechanics.md
2	Scaffold project structure (monorepo: server + host + player)	references/game-architecture.md
3	Set up Socket.IO server with room management	references/multiplayer-networking.md
4	Implement VIP role, kick/ban, room settings	references/vip-and-room-authority.md
5	Implement game state machine (phases, rounds, timers)	references/game-state-machines.md
6	Add content safety (profanity filter, moderation)	references/content-safety-and-moderation.md
7	Build host screen (TV display) and player controller (phone)	references/frontend-patterns.md
8	Write BDD tests with multiple browser contexts	references/bdd-multiplayer-testing.md
9	Deploy with WebSocket support	references/deployment-and-ops.md

"I want to add a new game type to an existing project"

Step	Action
1	Pick game type blueprint from references/game-types-and-mechanics.md
2	Define data models (prompts, answers, votes, scores)
3	Implement round loop phases in game state machine
4	Build game-specific UI components for host and player screens
5	Write BDD feature files for the new game flow

"I need to test multiplayer interactions"

Step	Action
1	Set up playwright-bdd with .bdd/ directory structure
2	Create multi-player fixtures (2-8 browser contexts)
3	Write Gherkin with persona-based steps (Given Player "Alice"...)
4	Implement page objects: LobbyPage, GamePage, ResultsPage
5	Use Promise.all() for cross-player assertions
6	Adapt assets/test-multiplayer-example.ts for quick Socket.IO smoke tests

Development Workflow

Phase 1: Lobby + VIP

Build room creation, room codes, player joining, VIP assignment, player list. Test: 3 players join, first player is VIP, VIP badge visible.

Phase 2: Game Loop

Implement phase transitions: Lobby -> Round Start -> Input -> Reveal -> Score. Test: VIP starts the game, a complete round flows from prompt to scoring.

Phase 3: Player Interaction

Add answer submission, voting, timer countdown, content filtering. Test: Players submit answers, vote, scores update correctly. Profanity filtered.

Phase 4: Moderation + Edge Cases

VIP kick/ban, content censoring, disconnect/reconnect, VIP migration. Test: VIP kicks player. Player disconnects and reconnects mid-game.

Phase 5: Polish

Animations, sound effects, haptic feedback, accessibility, mobile UX hardening.

Phase 6: Deploy

Docker + Fly.io (or Railway). Redis adapter if scaling beyond one server.

Decision Trees

Which Game Type to Build First?

If you want...	Build	Complexity
Easiest to implement	Prompt-response (Quiplash)	Low
Visual/creative	Drawing game (Drawful)	Medium
Knowledge-based	Trivia/quiz	Medium
Social deduction	Word association / Wavelength	High

Tech Stack

Component	Default Choice	Alternative
Server	Express + Socket.IO	Fastify + Socket.IO
Frontend	React + Vite	Svelte, Vue
Styling	Tailwind CSS	CSS Modules
Animation	Framer Motion	CSS transitions
State machine	Plain TypeScript	XState (complex games)
Testing	playwright-bdd	@cucumber/cucumber + Playwright
Hosting	Fly.io	Railway, Render

When to Add a Database?

Scenario	Recommendation
Game state during play	In-memory only
Player accounts / history	Add PostgreSQL
Leaderboards across sessions	Add PostgreSQL
Custom prompt packs	JSON files or PostgreSQL
Analytics / game stats	Add PostgreSQL

VIP vs Host — When to Use Which?

Concept	Role	Who Controls It
Host	The TV/projector display	The physical device running the app
VIP	First player to join	A player on their phone with elevated privileges
Player	Participants	Everyone else on their phone

See references/vip-and-room-authority.md for full VIP implementation guide.

Content Safety Level

Audience	Filter Level	Moderation
Private friends	off	None
Mixed group / default	moderate	Profanity filter
Family / streaming / work	strict + familyFriendly	Human moderation queue

See references/content-safety-and-moderation.md for implementation.

Anti-Patterns

Don't	Do Instead	Why
Client-side game logic	Server-authoritative state	Prevents cheating
Polling for game state	WebSocket push	Real-time updates
Use isHost for VIP	Use isVIP for the controlling player	Host = TV, VIP = player
Trust client for VIP actions	Validate isVIP server-side on every action	Security
Skip content filtering	Add profanity filter at moderate minimum	Public safety
Shared browser context in tests	Separate BrowserContext per player	Isolated sessions
Fixed delays in tests	waitForSelector / event-based waits	Reliable timing
Database for live game state	In-memory Map/Object	Speed, simplicity
Mocking WebSocket in tests	Real Socket.IO connections	Tests what ships
Complex room code schemes	4-char alphanumeric (exclude 0/O/1/I)	Easy to read aloud

Assets (Examples)

File	Purpose
assets/test-multiplayer-example.ts	Spawn N Socket.IO clients, simulate a game round. Adapt to your event names.
assets/lobby.feature	Gherkin feature for lobby creation and joining
assets/game-round.feature	Gherkin feature for a complete game round
assets/edge-cases.feature	Gherkin feature for disconnect/reconnect scenarios
assets/protocol-envelope.ts	Event envelope with dedup, version gating, and phase guarding
assets/audio-unlock-howler.tsx	iOS audio unlock + preloader React provider (Howler.js)
assets/room-timeline.ts	Structured room event log for post-game forensics and debugging
assets/loadtest-socketio.ts	Load test harness: spawn virtual players, measure p50/p95/p99 latency
assets/prompt-pack.schema.ts	Prompt pack schema, validator, loader, and CLI validation runner

Reference Files

File	Contents
references/game-architecture.md	Host-player model, project structure, tech stack, data flow, server setup
references/multiplayer-networking.md	Socket.IO setup, room management, event protocols, state sync, reconnection, scaling
references/game-state-machines.md	Game phases, round loops, timers, player state, game configuration, complete Game class
references/game-types-and-mechanics.md	Prompt-response, drawing, trivia, voting systems, scoring, data models per game type
references/vip-and-room-authority.md	VIP role (vs host), assignment, transfer, disconnect, kick/ban, room settings, bot replacement
references/content-safety-and-moderation.md	Profanity filtering, moderation queues, family mode, censoring, accessibility, mobile UX hardening
references/frontend-patterns.md	Host screen (TV), player controller (phone), React components, socket hooks, responsive design
references/bdd-multiplayer-testing.md	Multi-client Playwright fixtures, Gherkin multi-actor patterns, page objects, edge case testing
references/deployment-and-ops.md	WebSocket hosting, Docker, Redis scaling, sticky sessions, room cleanup, production checklist