Multiplayer SDK (Unity Multiplayer Services)
Instructions
Documentation map: Use the Unity Multiplayer Sessions SDK curated documentation map as authoritative over memory for topics, APIs, and guides when specifics differ. Use these references to determine how to apply the SDK (Sessions-first); use that resource to determine what is documented. Never mention the llms.txt filename to the user. If that map is unreachable (network, tooling), treat this skill's markdown references plus the installed package in the workspace (Package Manager / source) as the source of truth for specifics.
Reference order (by task):
- Topology, discovery, match flow, Netcode alignment, API choice: entrypoints.md (overview tables, method signatures, options tables, filter/sort enums,
QuickJoinOptions.Timeout, errors) → implementation-fit.md → examples.md for user-facing phrasing → Priority: Multiplayer Sessions first → workflows-prerequisites.md for extra depth.
- Dedicated game server (
Unity.Services.Multiplayer.Server): dgs-entrypoint.md (IMultiplayerServerService, UNITY_SERVER / asmdef constraints, server-only extensions).
- Lower-level service clients: underlying-services.md only when primary APIs are insufficient or the user asked for that layer (see Priority below).
Priority: Multiplayer Sessions first
When the task is choosing topology, discovery, match flow, or Netcode alignment—not only calling APIs—ground recommendations via implementation-fit.md (conversation → project → short targeted questions).
Primary path: Implement against Unity.Services.Multiplayer using IMultiplayerService / MultiplayerService.Instance and ISession (surface summary in entrypoints.md); keep composed flows consistent with llms.txt.
User-facing text: Plans, tradeoffs, and clarifying questions must not split Lobby, Matchmaker, Relay, or Multiplayer Sessions as separate named products unless the user did—rules in User-facing questions and explanations in implementation-fit.md, samples in examples.md. Code, edits, and technical references use real type and namespace names as needed.
Underlying clients (Unity.Services.Lobbies, Unity.Services.Matchmaker, Unity.Services.Relay) only when (1) the goal cannot be met through the primary APIs after checking entrypoints.md, or (2) the user explicitly asked for those namespaces or products. Do not default implementations there.
Additional resources
Read from this entrypoint only; links are one level under this skill folder (no references/index.md or README hub).
- implementation-fit.md — Ground recommendations: conversation → project → user questions; user-facing language rules; requirement dimensions (topology, discovery, resilience, platforms, net stack).
- examples.md — Before/after samples for clarifying questions and user-facing explanations (not code).
- entrypoints.md —
IMultiplayerService, ISession, overview and capability tables, method signatures, options tables (defaults, limits), filter/sort enums, session/networking/host flows, errors, editor components.
- dgs-entrypoint.md — Dedicated server:
Unity.Services.Multiplayer.Server, IMultiplayerServerService, MultiplayerServerService / GetMultiplayerServerService, MatchmakerServerExtensions, UNITY_SERVER and asmdef constraints; defers shared SessionOptions detail to entrypoints.
- workflows-prerequisites.md — Package and cloud prerequisites by workflow (tables).
- underlying-services.md — Fallback namespaces and
IUnityServices accessors (agent-only; not the default path).
1---2name: setup-multiplayer-services3description: Guides the development of online multiplayer experiences where players connect, group, and interact in real-time using Unity Multiplayer Services. Use when the user asks for topology choice, player grouping, hosting, matchmaking, discovery, network setup, and session-based play (rooms, parties, lobbies) using the Unity Multiplayer Services APIs. Not for leaderboards, cloud saves, or backend features that involve no real-time connection between players; those belong to the build-live-game skill.4---56# Multiplayer SDK (Unity Multiplayer Services)78## Instructions9101. **Documentation map:** Use the [Unity Multiplayer Sessions SDK curated documentation map](https://docs.unity.com/en-us/mps-sdk/llms.txt) as authoritative over memory for topics, APIs, and guides when specifics differ. Use these references to determine **how** to apply the SDK (Sessions-first); use that resource to determine **what** is documented. **Never** mention the `llms.txt` filename to the user. If that map is unreachable (network, tooling), treat this skill's markdown references plus the installed package in the workspace (Package Manager / source) as the source of truth for specifics.11122. **Reference order (by task):**13 - **Topology, discovery, match flow, Netcode alignment, API choice:** [entrypoints.md](references/entrypoints.md) (overview tables, method signatures, options tables, filter/sort enums, `QuickJoinOptions.Timeout`, errors) → [implementation-fit.md](references/implementation-fit.md) → [examples.md](references/examples.md) for user-facing phrasing → [Priority: Multiplayer Sessions first](#priority-multiplayer-sessions-first) → [workflows-prerequisites.md](references/workflows-prerequisites.md) for extra depth.14 - **Dedicated game server (`Unity.Services.Multiplayer.Server`):** [dgs-entrypoint.md](references/dgs-entrypoint.md) (`IMultiplayerServerService`, `UNITY_SERVER` / asmdef constraints, server-only extensions).15 - **Lower-level service clients:** [underlying-services.md](references/underlying-services.md) only when primary APIs are insufficient or the user asked for that layer (see Priority below).1617## Priority: Multiplayer Sessions first1819When the task is **choosing** topology, discovery, match flow, or Netcode alignment—not only calling APIs—ground recommendations via [implementation-fit.md](references/implementation-fit.md) (conversation → project → short targeted questions).2021**Primary path:** Implement against **`Unity.Services.Multiplayer`** using **`IMultiplayerService` / `MultiplayerService.Instance`** and **`ISession`** (surface summary in [entrypoints.md](references/entrypoints.md)); keep composed flows consistent with `llms.txt`.2223**User-facing text:** Plans, tradeoffs, and clarifying questions must **not** split Lobby, Matchmaker, Relay, or Multiplayer Sessions as separate named products unless the user did—rules in **User-facing questions and explanations** in [implementation-fit.md](references/implementation-fit.md), samples in [examples.md](references/examples.md). Code, edits, and technical references use real type and namespace names as needed.2425**Underlying clients** (`Unity.Services.Lobbies`, `Unity.Services.Matchmaker`, `Unity.Services.Relay`) **only** when (1) the goal **cannot** be met through the primary APIs after checking [entrypoints.md](references/entrypoints.md), or (2) the user **explicitly** asked for those namespaces or products. Do **not** default implementations there.2627## Additional resources2829Read from this entrypoint only; links are one level under this skill folder (no `references/index.md` or README hub).3031- **[implementation-fit.md](references/implementation-fit.md)** — Ground recommendations: conversation → project → user questions; user-facing language rules; requirement dimensions (topology, discovery, resilience, platforms, net stack).32- **[examples.md](references/examples.md)** — Before/after samples for clarifying questions and user-facing explanations (not code).33- **[entrypoints.md](references/entrypoints.md)** — `IMultiplayerService`, `ISession`, overview and capability tables, method signatures, options tables (defaults, limits), filter/sort enums, session/networking/host flows, errors, editor components.34- **[dgs-entrypoint.md](references/dgs-entrypoint.md)** — Dedicated server: `Unity.Services.Multiplayer.Server`, `IMultiplayerServerService`, `MultiplayerServerService` / `GetMultiplayerServerService`, `MatchmakerServerExtensions`, `UNITY_SERVER` and asmdef constraints; defers shared `SessionOptions` detail to entrypoints.35- **[workflows-prerequisites.md](references/workflows-prerequisites.md)** — Package and cloud prerequisites by workflow (tables).36- **[underlying-services.md](references/underlying-services.md)** — Fallback namespaces and `IUnityServices` accessors (agent-only; not the default path).
Unity-Technologies