playbooks

home / skills / vudovn / antigravity-kit / multiplayer

multiplayer skill

/.agent/skills/game-development/multiplayer

This skill helps you design and optimize multiplayer architecture, synchronization, and security by applying proven principles for latency, fairness, and

npx playbooks add skill vudovn/antigravity-kit --skill multiplayer

Review the files below or copy the command above to add this skill to your agents.

Files (1)
SKILL.md
2.7 KB
---
name: multiplayer
description: Multiplayer game development principles. Architecture, networking, synchronization.
allowed-tools: Read, Write, Edit, Glob, Grep, Bash
---

# Multiplayer Game Development

> Networking architecture and synchronization principles.

---

## 1. Architecture Selection

### Decision Tree

```
What type of multiplayer?
│
├── Competitive / Real-time
│   └── Dedicated Server (authoritative)
│
├── Cooperative / Casual
│   └── Host-based (one player is server)
│
├── Turn-based
│   └── Client-server (simple)
│
└── Massive (MMO)
    └── Distributed servers
```

### Comparison

| Architecture | Latency | Cost | Security |
|--------------|---------|------|----------|
| **Dedicated** | Low | High | Strong |
| **P2P** | Variable | Low | Weak |
| **Host-based** | Medium | Low | Medium |

---

## 2. Synchronization Principles

### State vs Input

| Approach | Sync What | Best For |
|----------|-----------|----------|
| **State Sync** | Game state | Simple, few objects |
| **Input Sync** | Player inputs | Action games |
| **Hybrid** | Both | Most games |

### Lag Compensation

| Technique | Purpose |
|-----------|---------|
| **Prediction** | Client predicts server |
| **Interpolation** | Smooth remote players |
| **Reconciliation** | Fix mispredictions |
| **Lag compensation** | Rewind for hit detection |

---

## 3. Network Optimization

### Bandwidth Reduction

| Technique | Savings |
|-----------|---------|
| **Delta compression** | Send only changes |
| **Quantization** | Reduce precision |
| **Priority** | Important data first |
| **Area of interest** | Only nearby entities |

### Update Rates

| Type | Rate |
|------|------|
| Position | 20-60 Hz |
| Health | On change |
| Inventory | On change |
| Chat | On send |

---

## 4. Security Principles

### Server Authority

```
Client: "I hit the enemy"
Server: Validate → did projectile actually hit?
         → was player in valid state?
         → was timing possible?
```

### Anti-Cheat

| Cheat | Prevention |
|-------|------------|
| Speed hack | Server validates movement |
| Aimbot | Server validates sight line |
| Item dupe | Server owns inventory |
| Wall hack | Don't send hidden data |

---

## 5. Matchmaking

### Considerations

| Factor | Impact |
|--------|--------|
| **Skill** | Fair matches |
| **Latency** | Playable connection |
| **Wait time** | Player patience |
| **Party size** | Group play |

---

## 6. Anti-Patterns

| ❌ Don't | ✅ Do |
|----------|-------|
| Trust the client | Server is authority |
| Send everything | Send only necessary |
| Ignore latency | Design for 100-200ms |
| Sync exact positions | Interpolate/predict |

---

> **Remember:** Never trust the client. The server is the source of truth.

Overview

This skill teaches multiplayer game development principles focused on architecture, networking, and synchronization. It distills design choices, latency mitigation, bandwidth optimization, and security practices into practical guidance for TypeScript-based game projects. Use it to choose architectures, implement sync models, and harden server authority.

How this skill works

The skill inspects common multiplayer scenarios and maps them to architectures (dedicated server, host-based, client-server, distributed). It explains synchronization models (state, input, hybrid), lag compensation techniques (prediction, interpolation, reconciliation), and network optimizations (delta compression, quantization, area of interest). It also covers security checks, anti-cheat patterns, and matchmaking criteria.

When to use it

  • Choosing an architecture for a new multiplayer title (real-time, turn-based, MMO, casual)
  • Designing client-server message flows and authority boundaries
  • Implementing prediction/interpolation for smooth player movement
  • Reducing bandwidth and CPU cost for networked entities
  • Hardening servers against common cheats and exploits

Best practices

  • Treat the server as the authoritative source of truth; validate all client claims
  • Pick sync strategy by game type: input-sync for action, state-sync for small deterministic worlds, hybrid for mixed needs
  • Use client-side prediction and server reconciliation to mask latency while preserving correctness
  • Compress and prioritize network messages: send deltas, quantize floats, and limit updates to nearby entities
  • Design for realistic latency (100–200ms) and test with simulated packet loss and jitter

Example use cases

  • Building a competitive shooter: dedicated authoritative server + input-sync + lag compensation for hits
  • Creating a cooperative couch-to-online game: host-based server with state-sync for simple objects
  • Launching a turn-based mobile game: lightweight client-server with event-driven updates
  • Scaling an MMO: sharded/distributed servers, area-of-interest filtering, and prioritized replication
  • Implementing anti-cheat: server-side movement validation, authoritative inventory, and minimal client visibility

FAQ

Which architecture gives the lowest latency?

Dedicated authoritative servers typically give the most consistent low latency and best security, at higher cost.

When should I use prediction vs interpolation?

Use prediction for local player responsiveness (client predicts its own actions) and interpolation for smoothing remote players' movements between received updates.