What problem does it solve? Multiplayer Decentraland scenes built on plain CRDT sync let any client write shared state, which enables cheating, desynchronized gameplay, and no safe place for secrets or persistent data. This Skill guides you through building scenes on the Decentraland Multiplayer Server (formerly Authoritative Server), where a headless server validates every change, owns game state, and persists data across sessions. ## Core Features & Use Cases - Server-authoritative state with anti-cheat validation: Define synced components guarded by validateBeforeChange(), verify player proximity server-side via PlayerIdentityData and Transform, and reject client writes to protected entities. - Client-server messaging and persistence: Use registerMessages() for typed bidirectional messages, Storage for scene and per-player persistence at checkpoints, and EnvVar for server-only secrets and live-tunable parameters. - Production-grade lifecycle handling: Implement server liveness heartbeats for cold starts, per-player synced entity patterns that avoid id collisions, and respect runtime resource limits like the 40 in-flight host-call cap. - Use Case: Build a competitive leaderboard scene where clients send claim actions, the headless server validates proximity to a score orb, increments scores itself, and persists per-player totals that survive server restarts. ## Quick Start Ask the AI to set up a Decentraland scene with the authoritative multiplayer server, including isServer() branching, a validated synced game-state component, and a join message flow.
