vrc-udon-core-module

vrc-udon-core-module is a skill for Codex from sechiro/VRCUdonSkills-for-Codex. It costs 130 tokens per session (704 once invoked), scanned A, original, MIT.

A structure guide for reusable VRChat UdonSharp modules. It separates code that runs in the world from editor tools that build or configure it, and keeps project-specific rules in project documentation.

In plain words
What is it for?
Starting UdonSharp modules, designing Builder-first workflows, separating Runtime and Editor folders, organizing documentation, and preparing reusable project foundations.
Why use it?
It helps modules remain understandable and portable when reused in other projects, while keeping runtime code and editor code from becoming mixed together.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: $skill-name invocation.

Good fit Starting UdonSharp modules, designing Builder-first workflows, separating Runtime and Editor folders, organizing documentation, and preparing reusable project foundations.

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Install with agentmods
npx agentmods add skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module
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 sechiro/VRCUdonSkills-for-Codex --skill vrc-udon-core-module
Clone the repo
git clone --depth 1 https://github.com/sechiro/VRCUdonSkills-for-Codex

Made for: Codex.

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 vrc-udon-core-module

README.md
[![agentmods](https://agentmods.dev/badge/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module/github.svg)](https://agentmods.dev/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module)
Your own site
<a href="https://agentmods.dev/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module"><img src="https://agentmods.dev/badge/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for vrc-udon-core-module

Your own site · 80×15
<a href="https://agentmods.dev/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module"><img src="https://agentmods.dev/badge/skills/sechiro/vrcudonskills-for-codex/vrc-udon-core-module.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 130 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 704 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 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 5.1 $0.00130 $0.00704
Opus 5 $0.00065 $0.00352
Sonnet 5 $0.00026 $0.00141
Haiku 4.5 $0.00013 $0.00070

Measured 10d ago against content hash 1a0cc16fd516, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

vrc-udon-core-module 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 10d 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.

skills/vrc-udon-core-module/SKILL.md · 52 lines

What it actually says

VRC Udon Core Module

役割

VRChat UdonSharp の再利用可能な基本モジュールを組み立てる。特に Builder First、Runtime / Editor 分離、project-owned な仕様書整備を前提にした初期構成を作る。

この Skill を最初に使う場面

  • 新しい UdonSharp モジュールを切り出す
  • Builder と Runtime の責務を分けたい
  • 外部プロジェクトへ持ち出せる基本骨格を作りたい

この Skill を使わない場面

  • 文書雛形だけを先に配りたい場合: vrc-udon-project-docs
  • ネットワーク仕様だけを決めたい場合: vrc-udon-networking-rules
  • Persistence の方式選定だけをしたい場合: vrc-udon-persistence-sync

進め方

  1. 最初に references/core-rules.md を読む。
  2. Builder を含む構成を作る場合は references/module-workflow.md も読む。
  3. まず責務を分ける。
    • Runtime は Scripts/ または Runtime/
    • Editor 拡張は Editor/
    • プロジェクト固有仕様は docs/
  4. 導入先に基本文書が無い場合は $vrc-udon-project-docs を併用する。
  5. Sync、Ownership、Network Event、Late Joiner、Persistence が絡む場合は $vrc-udon-networking-rules を併用する。
  6. Builder First を維持する。
  7. Runtime の UdonSharpBehaviour は小さく保つ。
  8. 他プロジェクトへ配布する前提でも、プロジェクト固有要件は project-owned ドキュメントに逃がす。

担当範囲

  • モジュールの基本構成決定
  • Builder の責務分離
  • Runtime の責務分離
  • 文書の最低ライン整理
  • 外部プロジェクトへ持ち出す前提の骨格化

担当しない範囲

  • Udon の個別ロジックを詳細実装すること
  • Unity MCP など個別機能の Runtime 実装を直接決め打ちすること
  • imported 資料の永続運用を常設前提にすること
  • ネットワーク仕様を単独で確定すること
Files

What ships with it

3 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. 10d ago First seen · 52 lines · 130 tokens per session scan A 1a0cc16fd516

Subscribe to this mod's changes

vrc-udon-core-module is a skill published in the GitHub repository sechiro/VRCUdonSkills-for-Codex (58 stars, last pushed 4mo ago), licensed MIT. It adds 130 tokens to every session and 704 once invoked, about $0.0006 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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