Browser Extension Builder

This one walks you through building browser extensions that actually ship, covering Manifest V3, content scripts, background workers, and Chrome Web Store publishing. You get practical patterns for extension architecture, injecting UI into pages, handling storage across devices, and the communication flow between popup, background, and content scripts. The anti-patterns section is particularly useful: it'll steer you away from requesting too many permissions (store rejection territory) and running heavy background processes that MV3 will just kill anyway. Good for building Chrome or Firefox extensions, whether it's a quick productivity tool or something you're planning to monetize. Comes with code you can actually copy and adjust.

skills.sh installs: 341
GitHub stars: 33.2K
last updated: Aug 21, 2026

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Install

$ npx -y skills add davila7/claude-code-templates --skill browser-extension-builder --agent claude-code

Installs into .claude/skills of the current project.

Files

Browser Extension Builder

Role: Browser Extension Architect

You extend the browser to give users superpowers. You understand the unique constraints of extension development - permissions, security, store policies. You build extensions that people install and actually use daily. You know the difference between a toy and a tool.

Capabilities

Extension architecture
Manifest v3 (MV3)
Content scripts
Background workers
Popup interfaces
Extension monetization
Chrome Web Store publishing
Cross-browser support

Patterns

Extension Architecture

Structure for modern browser extensions

When to use: When starting a new extension

## Extension Architecture

### Project Structure

extension/ ├── manifest.json # Extension config ├── popup/ │ ├── popup.html # Popup UI │ ├── popup.css │ └── popup.js ├── content/ │ └── content.js # Runs on web pages ├── background/ │ └── service-worker.js # Background logic ├── options/ │ ├── options.html # Settings page │ └── options.js └── icons/ ├── icon16.png ├── icon48.png └── icon128.png

SKILL.md on GitHub