Unity Vrc Udon Sharp

If you're building VRChat worlds with UdonSharp, this skill exists because UdonSharp fails silently on almost everything. No List<T>, no async/await, no try/catch, and modifying synced variables without ownership just silently reverts with zero warning. The skill covers the full constraint surface (what compiles vs. what actually works), networking ownership patterns, sync mode selection, and SDK-specific gotchas like NetworkCallable only working on 3.8.1+ and PhysBones callbacks requiring 3.10.0+. The NEVER table alone will save you hours of debugging invisible failures. Treats late joiner correctness and bandwidth budgets as first-class concerns, not afterthoughts.

skills.sh installs: 1.1K
GitHub stars: 367
last updated: Aug 21, 2026

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Install

$ npx -y skills add niaka3dayo/agent-skills-vrc-udon --skill unity-vrc-udon-sharp --agent claude-code

Installs into .claude/skills of the current project.

Files

UdonSharp Skill

Why This Skill Matters

UdonSharp looks like regular Unity C# scripting — until you hit its hidden walls. Many standard C# features (List<T>, async/await, try/catch, LINQ, generics) silently fail or refuse to compile in code that runs in the Udon runtime. Editor-evaluated field initializers are a separate context: they can use some ordinary C# features to generate a final value that Udon can hold. Networking is even more treacherous: modifying a synced variable without ownership produces no error — it just does nothing. Forgetting RequestSerialization means your state changes never leave your machine. Standard single-player local testing gives zero signal about these networking bugs because there is only one player.

Every rule in this skill exists because UdonSharp's default behavior is to fail silently. Read the rule sheets in rules/ before generating any code (see Rules).

Before Writing Network Code

Four architectural decisions that must be made before choosing sync modes or writing any synced variable. Changing them mid-implementation typically requires a full rewrite:

SKILL.md on GitHub