Icon Composer Skill plugin
A skill that creates, validates and renders Apple Icon Composer .icon packages without opening the graphical app.
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Extended access
Why this level
- The skill runs bundled Python programs and `ictool` and creates and overwrites `.icon` files on disk.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add plugins/icon-composer-skillDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The skill runs bundled Python programs and `ictool` and creates and overwrites `.icon` files on disk.
This is third-party code. Review the repository files before installing.
What it does
The `icon-composer` plugin with one `compose-app-icon` skill works with Apple Icon Composer icon packages. The agent creates a new `.icon` or edits `icon.json` in place and checks the result immediately. Two small Python programs, `create_icon.py` and `validate_icon.py`, plus the `icon-schema.json` schema are bundled for this. Validation checks `icon.json` against the schema and finds references to files missing from `Assets/`, explaining errors in schema terms. The schema covers Icon Composer versions 1 and 2, including overrides for appearance, idiom and localization and Liquid Glass properties. On macOS with Xcode the skill renders any variant to PNG through `ictool` from `Icon Composer.app` to show the light, dark and tinted versions.
Who it is for. iOS and macOS developers and icon designers who want an agent to build and validate `.icon` files without manual work in Icon Composer.
Good fit when
- You need to create an app icon from layers and describe dark and tinted versions.
- Icon Composer refuses to open a package and it is unclear why.
- The dark-mode colour of an icon must change by editing `icon.json`.
- Before release you want PNG previews of the icon for different platforms and appearances.
Not a fit when
- You need artistic icon drawing: the skill assembles a package from ready layers.
- `uv` is missing on the machine: the skill stops at the preflight check.
- Rendering is needed outside macOS: `ictool` ships only in Icon Composer on a Mac with Xcode.
Example request
Assemble an app icon from the layers in `Assets`, set a dark background and validate the package before rendering the dark variant.Limitations
`uv` on `PATH` is required: the skill runs its bundled Python programs through it and stops with an error without it. PNG rendering works only on macOS with Xcode, where `ictool` is found via `xcode-select -p`. Installing through `gh skill` needs GitHub CLI 2.90.0 or newer. The skill does not draw layers and works with the assets you put in `Assets/`. For Codex the plugin installs through its plugin directory after adding the marketplace.
How to disable. Remove the `icon-composer` plugin through the Claude Code or Codex plugin manager, or the skill folder added through `gh skill`. Packages you created stay with you.
FAQ
How do I install the skill in Claude Code?
Run `/plugin marketplace add giginet/apple-icon-composer-skill`, then `/plugin install icon-composer@icon-composer` and `/reload-plugins`. `/icon-composer:compose-app-icon` appears in the command list.
How do I install it in Codex?
The `codex plugin marketplace add giginet/apple-icon-composer-skill` command adds the marketplace. Then open the Codex plugin directory, pick Icon Composer and install.
Is there a GitHub CLI option?
Yes: `gh skill install giginet/apple-icon-composer-skill`, and for a specific host add `compose-app-icon --agent claude-code`. The whole set is copied, including the programs in `scripts/`.
What does `validate_icon.py` check?
That `icon.json` matches the schema through `jsonschema` and that referenced files exist in `Assets/`. Errors are explained in schema terms.
How do I see the icon?
The skill renders a platform and appearance to PNG through `ictool` on macOS with Xcode. That lets you check the light, dark and tinted variants.
Discussion
No questions or reviews yet.
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README in short
The README lists three install paths, describes the single skill and its triggers and shows the repository layout. Commands for local development and checking fixtures close it.