NekoCore-OS app-builder

Build, install, and manage complete NekoCore OS apps — HTML payload, installer contract, window registration, start menu category. Produces installer-managed, reversible app packages.

install

source · Clone the upstream repo

git clone https://github.com/voardwalker-code/NekoCore-OS

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/voardwalker-code/NekoCore-OS "$T" && mkdir -p ~/.claude/skills && cp -r "$T/project/MA/MA-skills/app-builder" ~/.claude/skills/voardwalker-code-nekocore-os-app-builder && rm -rf "$T"

manifest: project/MA/MA-skills/app-builder/SKILL.md

source content

App Builder Skill

You can create complete NekoCore OS applications that run as windowed apps inside the desktop environment.

What You Can Do

Design app UI — plan layout, sections, controls for any app type
Write HTML payloads — self-contained tab-content files with script logic
Build installer contracts — JSON contracts for repeat-safe install/uninstall
Install apps — run the installer CLI to wire up all registrations
Uninstall apps — cleanly reverse any installed app

Triggers

"build an app", "create an app", "make an app"
"NekoCore app", "new app", "app builder"
"install an app", "add an app"

Workflow

Gather requirements: name, purpose, features, category, icon
Design the layout and interaction model

Write the HTML payload to

client/apps/non-core/core/tab-<appId>.html

PAUSE — show the user what was built, get approval

Write the installer contract to

server/contracts/installer-<appId>.contract.example.json

Run installer dry-run, then actual install
Verify all 4 registration points (payload, loader, window registry, category map)

Key Rules

appId must match across ALL surfaces: contract, loader tabId, WINDOW_APPS tab, category map key
Container ID must be
```
tab-<appId>
```
Script logic wrapped in IIFE with idempotent guard
No
<link>
or
<style>
tags — inline styles or system classes only
Use CSS variables for theme compatibility:
```
var(--ac)
```
,
```
var(--tm)
```
,
```
var(--sf2)
```
, etc.
Dispose function required for apps with intervals/listeners
Relative API URLs only — never hardcode ports

Tools Used

[TOOL:ws_write path="client/apps/non-core/core/tab-{appId}.html"]    — write app HTML
[TOOL:ws_write path="server/contracts/installer-{appId}.contract.example.json"] — write contract
[TOOL:ws_read path="client/apps/non-core/core/tab-{appId}.html"]     — verify payload
[TOOL:cmd_run cmd="node server/tools/installer-cli.js install --contract ... --root . --dry"] — dry-run
[TOOL:cmd_run cmd="node server/tools/installer-cli.js install --contract ... --root . --log ..."] — install
[TOOL:cmd_run cmd="node server/tools/installer-cli.js uninstall --contract ... --root ."] — uninstall

App Categories

tools

(default),

browse

mind

journal

appearance

system

Quality Checklist

appId consistent across all 4 registration points
HTML container is
```
tab-<appId>
```
Script in IIFE with init guard
No global variable leaks
Dispose function handles cleanup
System CSS classes used where available
Installer dry-run passes
All registration entries verified post-install