unity-prefab

An AI agent skill for reading and editing Unity prefab files (.prefab) through the ubridge CLI.

Converts Unity's verbose YAML into a compact .ubridge format optimized for AI comprehension — 92-96% token reduction with lossless round-trip fidelity.

Install

Via skills CLI (recommended)

# Global install (available in all projects)
npx skills add yulcat/unity-prefab -a claude-code -g

# Project-local install (share with team via git)
npx skills add yulcat/unity-prefab -a claude-code

Also works with Codex, Cursor, Gemini CLI, and 40+ other agents.

Manual

git clone https://github.com/yulcat/unity-prefab ~/.claude/skills/unity-prefab

Dependency

This skill requires the ubridge CLI:

npm i -g --install-links github:yulcat/unity-yaml-bridge

The skill instructs the agent to install it automatically if missing.

What It Does

When you ask an AI agent to inspect or edit a Unity prefab, this skill teaches it to:

1. Parse — Convert .prefab → .ubridge (compact, readable)
2. Read — Understand the GameObject hierarchy, components, and properties
3. Edit — Modify properties, add/remove GameObjects, rewire references
4. Write back — Convert .ubridge → .prefab (lossless)

Key Features

• Nested prefab expansion — Recursively inlines child hierarchies from nested prefab instances
• Path references (->) — Human-readable ->Button:Image instead of opaque {fileID} numbers
• Variant support — Shows only overrides with * markers on modified components
• MonoBehaviour GUID resolution — Shows actual C# class names instead of raw GUIDs
• Name collision handling — Sibling GOs with same name get #1, #2 suffixes
• 92-96% token reduction — Makes prefabs feasible for LLM context windows

Example

A Unity prefab that looks like this in YAML (9,488 bytes):

--- !u!1 &8027481463175804169
GameObject:
  m_ObjectHideFlags: 0
  m_CorrespondingSourceObject: {fileID: 0}
  ...hundreds of lines...

Becomes this in .ubridge (698 bytes):

--- STRUCTURE
Button [ButtonActivation]
├─ Background9Slice_Image [Image]
└─ Button_Text {SkillName_Text} [TextMeshProUGUI]
--- DETAILS
[Button:ButtonActivation]
activateDisplayText = ->Button_Text:TextMeshProUGUI

Links

• ubridge CLI: yulcat/unity-yaml-bridge
• Format spec: docs/FORMAT.md
• Agent Skills standard: agentskills.io

License

MIT