engineering-game-state-sync

engineering-game-state-sync is a skill for Claude Code from fcsouza/agent-skills. It costs 47 tokens per session (3,147 once invoked), scanned A, original, GPL-3.0.

A guide for keeping game data consistent between a player’s device and the game server. It covers sending only changes, showing predicted results, undoing incorrect results, and reconciling real-time updates.

In plain words
What is it for?
Use it when building multiplayer movement, actions, combat, or other real-time features that must stay synchronized across clients and the server.
Why use it?
It helps deal with slow or unreliable connections and differences between what the player sees and what the server accepts. These techniques reduce unnecessary data transfer and correct mismatched game state.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the game-dev plugin — 25 skills, 7 commands, 3 agents, 5 hooks, 3 MCP servers shipped together

Good fit Use it when building multiplayer movement, actions, combat, or other real-time features that must stay synchronized across clients and the server.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fcsouza/agent-skills/game-state-sync
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.

Any agent
npx skills add fcsouza/agent-skills --skill game-state-sync
Clone the repo
git clone --depth 1 https://github.com/fcsouza/agent-skills

Made for: Claude Code.

Or install game-dev, the plugin that ships this one along with the rest of its 25 skills, 7 commands, 3 agents, 5 hooks, 3 MCP servers.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for engineering-game-state-sync

README.md
[![agentmods](https://agentmods.dev/badge/skills/fcsouza/agent-skills/game-state-sync.svg)](https://agentmods.dev/skills/fcsouza/agent-skills/game-state-sync)
Your own site
<a href="https://agentmods.dev/skills/fcsouza/agent-skills/game-state-sync"><img src="https://agentmods.dev/badge/skills/fcsouza/agent-skills/game-state-sync.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,147 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 5.1 $0.00047 $0.03147
Opus 5 $0.00023 $0.01573
Sonnet 5 $0.00009 $0.00629
Haiku 4.5 $0.00005 $0.00315

Measured 8d ago against content hash 4ba4d6b3324f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

engineering-game-state-sync 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 8d ago.

The scan reads SKILL.md. This mod also ships 5 executable files (boilerplate/delta-encoder.ts, boilerplate/game-loop-client.ts, boilerplate/rollback-buffer.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/game-dev/engineering/game-state-sync/SKILL.md · 373 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 8d ago First seen · 373 lines · 47 tokens per session scan A 4ba4d6b3324f

Subscribe to this mod's changes

engineering-game-state-sync is a skill published in the GitHub repository fcsouza/agent-skills (20 stars, last pushed 6d ago), licensed GPL-3.0. It adds 47 tokens to every session and 3,147 once invoked, about $0.0002 per session on Opus 5. 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 2026-08-30.

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