# Addon

> Browser and software addon architecture reference — extension APIs, manifest formats, lifecycle hooks, and plugin security models. Use when building browser extensions, designing plugin systems, or understanding addon sandboxing.

- Skill: `bytesagain/addon` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add bytesagain/addon`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bytesagain/addon/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: bytesagain (https://skillmd.com/u/bytesagain)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/bytesagain/addon

---


# Addon — Addon & Extension Architecture Reference

Quick-reference skill for browser extension development, plugin system design, and addon security.

## When to Use

- Building browser extensions (Chrome, Firefox, Safari)
- Designing plugin/addon architectures for applications
- Understanding extension manifest formats and permissions
- Implementing addon lifecycle hooks and event systems
- Reviewing addon security models and sandboxing

## Commands

### `intro`

```bash
scripts/script.sh intro
```

Overview of addon/extension architecture — types, platforms, and design patterns.

### `manifest`

```bash
scripts/script.sh manifest
```

Extension manifest formats — Manifest V3, permissions, content scripts.

### `lifecycle`

```bash
scripts/script.sh lifecycle
```

Addon lifecycle — install, activate, update, disable, uninstall hooks.

### `apis`

```bash
scripts/script.sh apis
```

Browser extension APIs — tabs, storage, messaging, alarms, notifications.

### `security`

```bash
scripts/script.sh security
```

Addon security — sandboxing, CSP, permission models, code review.

### `patterns`

```bash
scripts/script.sh patterns
```

Plugin architecture patterns — hook systems, middleware, event buses.

### `messaging`

```bash
scripts/script.sh messaging
```

Inter-component messaging — background ↔ content script ↔ popup communication.

### `publishing`

```bash
scripts/script.sh publishing
```

Publishing addons — Chrome Web Store, AMO, review process, updates.

### `help`

```bash
scripts/script.sh help
```

### `version`

```bash
scripts/script.sh version
```

## Configuration

| Variable | Description |
|----------|-------------|
| `ADDON_DIR` | Data directory (default: ~/.addon/) |

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