PrefabLens

Human-readable diffs for UnityYAML assets. Instead of raw text diffs, PrefabLens shows changes at the GameObject, component, and field level.

Try the live demo.

Chrome extension (Chrome Web Store)

Unity Editor

CLI

Components

Directory	Description
core/	Diff engine in Zig (shared by the CLI and WASM)
cli/	prefablens command-line tool
extension/	Chrome extension for semantic diffs on GitHub pull requests
editor/	Unity Editor package for semantic UnityYAML diffs
site/	Live demo site published to GitHub Pages, built from the CLI and extension artifacts

Installation

Chrome extension (Chrome Web Store)

Install from the Chrome Web Store.

CLI

Homebrew (macOS / Linux)

brew install hashiiiii/tap/prefablens

Scoop (Windows)

scoop bucket add hashiiiii https://github.com/hashiiiii/scoop-bucket
scoop install prefablens

mise

mise use -g github:hashiiiii/PrefabLens

Manual

Download the zip for your platform from GitHub Releases.

Unity Editor package (OpenUPM)

Requires Unity 2022.3+.

openupm add com.hashiiiii.prefablens

Without the openupm-cli, add the scoped registry as described on the package page, or install via the Package Manager git URL: https://github.com/hashiiiii/PrefabLens.git?path=editor.

Usage

Chrome extension

Shows semantic diffs for UnityYAML files on the GitHub pull request Files changed tab. Sign in with GitHub from the first diff panel (or the extension options page); authorization uses the GitHub device flow, so no token setup is needed.

Note

The extension is currently available on github.com only.

CLI

prefablens                              # HEAD vs working tree, all changed Unity files
prefablens Assets/Foo.prefab            # HEAD vs working tree, one file
prefablens main                         # ref vs working tree, all changed Unity files
prefablens HEAD~1 HEAD Assets/Foo.prefab  # ref vs ref, one file
prefablens before.prefab after.prefab   # plain two-file compare (no git)

prefablens --json before.prefab after.prefab
prefablens --html main                  # self-contained HTML report on stdout
prefablens --open main                  # write the report to a temp file and open it

Operands ending in a Unity YAML extension (.prefab, .unity, .asset, ...) are treated as paths; everything else is a git ref.

Full reference — every flag, exit code, and resolution rule: docs/cli.md.

Unity Editor

Open Window > PrefabLens. The window lists every changed UnityYAML asset vs HEAD and shows the selected asset's semantic diff. The CLI binary is downloaded automatically from GitHub Releases.

Details — configuration, the CLI download, troubleshooting: docs/editor.md.

Supported files

Text-serialized Unity assets such as .prefab, .unity, .asset, .mat, .anim, and .controller. Excludes .meta, .asmdef, and other non-UnityYAML formats.

Development

Toolchain is managed with mise (Zig 0.16, Node 24, pnpm 11, .NET 10).

mise install

# Core / CLI
zig build test
zig build run -- before.prefab after.prefab

# WASM (for the extension)
zig build wasm

# Extension
cd extension && pnpm install && pnpm run build && pnpm test

# Editor (EditMode tests run on .NET, no Unity required)
cd editor && dotnet test DotNetTests~/Tests

# Site (build the CLI, WASM, and extension demo bundle first: `pnpm run demo`)
cd site && node --test src/*.test.mjs && node build.mjs

Contributing

Contributions follow an issue-first flow: open an issue and wait for the approved label before sending a pull request. See CONTRIBUTING.md for details.

License

Apache License 2.0