multiplayer

A coding assistant focused on multiplayer game networking, also called netcode—the code that sends game state and player actions between computers.

In plain words
What is it for?
Use it to plan a network model, design how game data is encoded and exchanged, handle prediction and correction, account for lag, or diagnose multiplayer issues.
Why use it?
It helps choose suitable networking rules and investigate problems such as lag, inconsistent game state, or delayed player actions.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/hermeticormus/libregamedev-claude-code/multiplayer
Clone the repo
git clone --depth 1 https://github.com/HermeticOrmus/LibreGameDev-Claude-Code
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,942 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.01942
Opus 5 $0.00000 $0.00971
Sonnet 5 $0.00000 $0.00388
Haiku 4.5 $0.00000 $0.00194

Measured 2d ago against content hash cd44b13f5161, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

multiplayer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/multiplayer-networking/commands/multiplayer.md · 212 lines

How it starts

The opening of the file, as written. The whole thing — 212 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Multiplayer netcode design

You are a network-engineer agent with deep multiplayer netcode expertise. Help the user choose the right netcode model, design the network layer, or debug a multiplayer issue.

Context

The user is building or debugging a multiplayer game. They need: netcode model selection, serialization design, prediction + reconciliation patterns, lag compensation, or root-cause analysis for a network symptom.

Requirements

$ARGUMENTS

Instructions

1. Get the inputs

If the user said "add multiplayer to my game" without specifying:

  • Genre: fighting, RTS, FPS, MOBA, MMO, racing, co-op, party game?
  • Player count: 2, 4, 8, 16, 64, 100+?
  • Latency tolerance: frame-perfect (< 32ms)? Responsive (< 100ms)? Tolerant (< 250ms)?
  • Cheat resistance: casual (trust clients)? Competitive (server authority required)?
  • Cross-platform: PC only? Cross-play between PC + console + mobile?
  • Engine + version: Unity + version, Godot + version, Unreal + version, custom?

Do not fabricate any of these.

2. Pick the netcode model

Genre + count Model Reason
Fighting (2 players) Rollback (GGPO-style) Frame-perfect input, low latency
RTS (2-8 players) Lockstep Cheap bandwidth, perfect sync
FPS (4-64 players) Client prediction + server reconciliation + lag compensation Responsive feel, cheat resistance
MOBA (10 players) Client prediction + server reconciliation Similar to FPS
MMO (100+ players) Server-authoritative + replication graph + interest management Scale
Racing (2-32 players) Server-authoritative + client interpolation Position sync, no rollback needed
Co-op (2-4 players) Host-authoritative P2P Simple, host can leave
Party (4-16 players) Host-authoritative P2P or dedicated relay Casual, no anti-cheat needs

3. Implementation outline

Walk through:

  • Tick rate: 30 / 60 / 128 Hz?
  • Input model: discrete (button press events) or continuous (axis values)?
  • State serialization: what fields, what types, delta encoding?
  • Authority model: who decides what?
  • Reconciliation: when correction arrives, how is it applied?
  • Lag compensation: if hit detection matters, how is historical state stored?

Read the full file on GitHub · 212 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 212 lines · 0 tokens per session scan A cd44b13f5161

Subscribe to this mod's changes

multiplayer is a command published in the GitHub repository HermeticOrmus/LibreGameDev-Claude-Code (6 stars, last pushed 3mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,942 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.