Adoption

Agent Skills are supported by leading AI development tools.

VS Code Gemini CLI GitHub Goose Amp Cursor Claude Code Letta OpenCode Claude OpenAI Codex Factory VS Code Gemini CLI GitHub Goose Amp Cursor Claude Code Letta OpenCode Claude OpenAI Codex Factory

a-organvm/browser-extension-patterns

Name: browser-extension-patterns
Author: a-organvm

distributions/claude/skills/browser-extension-patterns/SKILL.md

npx skillsauth add a-organvm/a-i--skills browser-extension-patterns

Clean

TrivyContainer and dependency vulnerability scanner

Clean

SemgrepStatic code analysis for vulnerabilities

Clean

mcp-scan (Snyk)Model Context Protocol security validation

Skipped

Snyk (dep)Open source security scanning

Skipped

Socket.devSupply chain security analysis

Skipped

VirusTotalMulti-engine malware detection

Skipped

CrowdStrikeAdvanced threat intelligence

Skipped

OSV-ScannerOpen Source Vulnerability database check

Skipped

OWASP Dep-Check

Browser Extension Patterns

Build cross-browser extensions with Manifest V3 architecture.

Manifest V3 Structure

my-extension/
├── manifest.json          # Extension manifest
├── background/
│   └── service-worker.js  # Background service worker
├── content/
│   └── content-script.js  # Injected into web pages
├── popup/
│   ├── popup.html         # Popup UI
│   ├── popup.js           # Popup logic
│   └── popup.css          # Popup styles
├── options/
│   ├── options.html       # Settings page
│   └── options.js
├── icons/
│   ├── icon-16.png
│   ├── icon-48.png
│   └── icon-128.png
└── _locales/              # Internationalization
    └── en/messages.json

Manifest Configuration

{
  "manifest_version": 3,
  "name": "My Extension",
  "version": "1.0.0",
  "description": "Brief description of what it does",
  "permissions": ["storage", "activeTab"],
  "host_permissions": ["https://*.example.com/*"],
  "background": {
    "service_worker": "background/service-worker.js"
  },
  "content_scripts": [{
    "matches": ["https://*.example.com/*"],
    "js": ["content/content-script.js"],
    "css": ["content/content-style.css"],
    "run_at": "document_idle"
  }],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "options_page": "options/options.html",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}

Background Service Worker

// background/service-worker.js

// Installation
chrome.runtime.onInstalled.addListener((details) => {
  if (details.reason === 'install') {
    chrome.storage.local.set({ settings: { enabled: true, theme: 'light' } });
  }
});

// Message handling from content scripts and popup
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  switch (message.type) {
    case 'getData':
      fetchData(message.url).then(sendResponse);
      return true; // Async response
    case 'updateBadge':
      chrome.action.setBadgeText({ text: String(message.count) });
      break;
  }
});

// Alarm-based periodic tasks (replaces MV2 persistent background)
chrome.alarms.create('sync', { periodInMinutes: 30 });
chrome.alarms.onAlarm.addListener((alarm) => {
  if (alarm.name === 'sync') syncData();
});

Content Scripts

// content/content-script.js

// DOM manipulation on target pages
function enhancePage() {
  const elements = document.querySelectorAll('.target-class');
  elements.forEach(el => {
    const badge = document.createElement('span');
    badge.className = 'my-extension-badge';
    badge.textContent = 'Enhanced';
    el.appendChild(badge);
  });
}

// Run when DOM is ready
if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', enhancePage);
} else {
  enhancePage();
}

// Communicate with background
async function requestData(url) {
  return chrome.runtime.sendMessage({ type: 'getData', url });
}

// Listen for messages from background/popup
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  if (message.type === 'getPageData') {
    sendResponse({ title: document.title, url: location.href });
  }
});

Storage Patterns

// Chrome storage API (synced across devices)
const storage = {
  async get(key) {
    const result = await chrome.storage.sync.get(key);
    return result[key];
  },

  async set(key, value) {
    await chrome.storage.sync.set({ [key]: value });
  },

  async getLocal(key) {
    const result = await chrome.storage.local.get(key);
    return result[key];
  },

  onChange(callback) {
    chrome.storage.onChanged.addListener((changes, area) => {
      callback(changes, area);
    });
  }
};

// Usage
await storage.set('settings', { theme: 'dark', enabled: true });
const settings = await storage.get('settings');

Popup UI

<!-- popup/popup.html -->
<!DOCTYPE html>
<html>
<head>
  <link rel="stylesheet" href="popup.css">
</head>
<body>
  <div id="app">
    <h2>My Extension</h2>
    <label>
      <input type="checkbox" id="enabled"> Enabled
    </label>
    <div id="status"></div>
  </div>
  <script src="popup.js"></script>
</body>
</html>

// popup/popup.js
document.addEventListener('DOMContentLoaded', async () => {
  const settings = await chrome.storage.sync.get('settings');
  document.getElementById('enabled').checked = settings.settings?.enabled;

  document.getElementById('enabled').addEventListener('change', async (e) => {
    await chrome.storage.sync.set({
      settings: { ...settings.settings, enabled: e.target.checked }
    });
    // Notify content scripts
    const [tab] = await chrome.tabs.query({ active: true, currentWindow: true });
    chrome.tabs.sendMessage(tab.id, { type: 'settingsChanged', enabled: e.target.checked });
  });
});

Cross-Browser Compatibility

// Polyfill for Firefox WebExtensions API
const browser = globalThis.browser || globalThis.chrome;

// Feature detection
const isFirefox = typeof browser !== 'undefined' && browser.runtime?.getBrowserInfo;
const isChrome = typeof chrome !== 'undefined' && chrome.runtime?.id;

Firefox Manifest Differences

{
  "background": {
    "scripts": ["background/service-worker.js"]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "[email protected]",
      "strict_min_version": "109.0"
    }
  }
}

Permission Strategy

| Permission | When | Impact | |-----------|------|--------| | activeTab | Need current tab only | Low (user-triggered) | | storage | Need to save settings | Low | | tabs | Need tab URLs/titles | Medium | | host_permissions | Need page access | High (shows warning) | | <all_urls> | Need all page access | Very High (avoid if possible) |

Principle: Request minimum permissions. Use activeTab over broad host permissions when possible.

Anti-Patterns

MV2 patterns in MV3 — No persistent background pages; use service workers and alarms
<all_urls> permission — Request only the hosts you need
Synchronous storage — Always use async chrome.storage API
No error handling in messaging — Messages fail silently if receiver doesn't exist
Heavy content scripts — Minimize injected code; communicate with background for heavy work
No uninstall cleanup — Use runtime.onInstalled to handle updates and cleanup

a-organvm/browser-extension-patterns

distributions/claude/skills/browser-extension-patterns/SKILL.md

Build browser extensions with Manifest V3 for Chrome, Firefox, and cross-browser compatibility. Covers content scripts, background workers, popup UI, storage APIs, and extension messaging. Triggers on browser extension development, Manifest V3, or Chrome extension requests.

6 stars

tools

Updated Apr 23, 2026

$ install --global

skillsauth

npx skillsauth add a-organvm/a-i--skills browser-extension-patterns

Install this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.

Security Scan Results

3 of 9 scanners reported clean

Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.

Scanners Passed

Scanners in report

Clean

TrivyContainer and dependency vulnerability scanner

95%

Clean

SemgrepStatic code analysis for vulnerabilities

95%

Clean

mcp-scan (Snyk)Model Context Protocol security validation

95%

Skipped

Snyk (dep)Open source security scanning

50%

Skipped

Socket.devSupply chain security analysis

50%

Skipped

VirusTotalMulti-engine malware detection

50%

Skipped

CrowdStrikeAdvanced threat intelligence

50%

Skipped

OSV-ScannerOpen Source Vulnerability database check

50%

Skipped

OWASP Dep-Check

50%

Last scanned: Apr 30, 2026, 9:42 PM8.5s1 file scanned

SKILL.md

name:: browser-extension-patterns
description:: Build browser extensions with Manifest V3 for Chrome, Firefox, and cross-browser compatibility. Covers content scripts, background workers, popup UI, storage APIs, and extension messaging. Triggers on browser extension development, Manifest V3, or Chrome extension requests.
license:: MIT
complexity:: intermediate
time_to_learn:: 30min
governance_phases:: [build]
organ_affinity:: [organ-iii]
triggers:: [user-asks-about-browser-extension, context:chrome-extension, context:manifest-v3, project-has-manifest-json]
complements:: [frontend-design-systems, testing-patterns, deployment-cicd]

Browser Extension Patterns

Build cross-browser extensions with Manifest V3 architecture.

Manifest V3 Structure

my-extension/
├── manifest.json          # Extension manifest
├── background/
│   └── service-worker.js  # Background service worker
├── content/
│   └── content-script.js  # Injected into web pages
├── popup/
│   ├── popup.html         # Popup UI
│   ├── popup.js           # Popup logic
│   └── popup.css          # Popup styles
├── options/
│   ├── options.html       # Settings page
│   └── options.js
├── icons/
│   ├── icon-16.png
│   ├── icon-48.png
│   └── icon-128.png
└── _locales/              # Internationalization
    └── en/messages.json

Manifest Configuration

{
  "manifest_version": 3,
  "name": "My Extension",
  "version": "1.0.0",
  "description": "Brief description of what it does",
  "permissions": ["storage", "activeTab"],
  "host_permissions": ["https://*.example.com/*"],
  "background": {
    "service_worker": "background/service-worker.js"
  },
  "content_scripts": [{
    "matches": ["https://*.example.com/*"],
    "js": ["content/content-script.js"],
    "css": ["content/content-style.css"],
    "run_at": "document_idle"
  }],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "options_page": "options/options.html",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}

Background Service Worker

// background/service-worker.js

// Installation
chrome.runtime.onInstalled.addListener((details) => {
  if (details.reason === 'install') {
    chrome.storage.local.set({ settings: { enabled: true, theme: 'light' } });
  }
});

// Message handling from content scripts and popup
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  switch (message.type) {
    case 'getData':
      fetchData(message.url).then(sendResponse);
      return true; // Async response
    case 'updateBadge':
      chrome.action.setBadgeText({ text: String(message.count) });
      break;
  }
});

// Alarm-based periodic tasks (replaces MV2 persistent background)
chrome.alarms.create('sync', { periodInMinutes: 30 });
chrome.alarms.onAlarm.addListener((alarm) => {
  if (alarm.name === 'sync') syncData();
});

Content Scripts

// content/content-script.js

// DOM manipulation on target pages
function enhancePage() {
  const elements = document.querySelectorAll('.target-class');
  elements.forEach(el => {
    const badge = document.createElement('span');
    badge.className = 'my-extension-badge';
    badge.textContent = 'Enhanced';
    el.appendChild(badge);
  });
}

// Run when DOM is ready
if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', enhancePage);
} else {
  enhancePage();
}

// Communicate with background
async function requestData(url) {
  return chrome.runtime.sendMessage({ type: 'getData', url });
}

// Listen for messages from background/popup
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  if (message.type === 'getPageData') {
    sendResponse({ title: document.title, url: location.href });
  }
});

Storage Patterns

// Chrome storage API (synced across devices)
const storage = {
  async get(key) {
    const result = await chrome.storage.sync.get(key);
    return result[key];
  },

  async set(key, value) {
    await chrome.storage.sync.set({ [key]: value });
  },

  async getLocal(key) {
    const result = await chrome.storage.local.get(key);
    return result[key];
  },

  onChange(callback) {
    chrome.storage.onChanged.addListener((changes, area) => {
      callback(changes, area);
    });
  }
};

// Usage
await storage.set('settings', { theme: 'dark', enabled: true });
const settings = await storage.get('settings');

Popup UI

<!-- popup/popup.html -->
<!DOCTYPE html>
<html>
<head>
  <link rel="stylesheet" href="popup.css">
</head>
<body>
  <div id="app">
    <h2>My Extension</h2>
    <label>
      <input type="checkbox" id="enabled"> Enabled
    </label>
    <div id="status"></div>
  </div>
  <script src="popup.js"></script>
</body>
</html>

// popup/popup.js
document.addEventListener('DOMContentLoaded', async () => {
  const settings = await chrome.storage.sync.get('settings');
  document.getElementById('enabled').checked = settings.settings?.enabled;

  document.getElementById('enabled').addEventListener('change', async (e) => {
    await chrome.storage.sync.set({
      settings: { ...settings.settings, enabled: e.target.checked }
    });
    // Notify content scripts
    const [tab] = await chrome.tabs.query({ active: true, currentWindow: true });
    chrome.tabs.sendMessage(tab.id, { type: 'settingsChanged', enabled: e.target.checked });
  });
});

Cross-Browser Compatibility

// Polyfill for Firefox WebExtensions API
const browser = globalThis.browser || globalThis.chrome;

// Feature detection
const isFirefox = typeof browser !== 'undefined' && browser.runtime?.getBrowserInfo;
const isChrome = typeof chrome !== 'undefined' && chrome.runtime?.id;

Firefox Manifest Differences

{
  "background": {
    "scripts": ["background/service-worker.js"]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "[email protected]",
      "strict_min_version": "109.0"
    }
  }
}

Permission Strategy

Principle: Request minimum permissions. Use activeTab over broad host permissions when possible.

Anti-Patterns

MV2 patterns in MV3 — No persistent background pages; use service workers and alarms
<all_urls> permission — Request only the hosts you need
Synchronous storage — Always use async chrome.storage API
No error handling in messaging — Messages fail silently if receiver doesn't exist
Heavy content scripts — Minimize injected code; communicate with background for heavy work
No uninstall cleanup — Use runtime.onInstalled to handle updates and cleanup

Related Skills

a-organvm/docx

development

VerifiedTrustedCommunity

Comprehensive document creation, editing, and analysis with support for tracked changes, comments, formatting preservation, and text extraction. When Claude needs to work with professional documents (.docx files) for: (1) Creating new documents, (2) Modifying or editing content, (3) Working with tracked changes, (4) Adding comments, or any other document tasks

12SKILL.mdUpdated Jul 20, 2026

a-organvm/workspace-autopsy-governance

development

VerifiedTrustedCommunity

Conducts a full automated autopsy of the current workspace directory to map files, identifies structural issues, proposes a restructuring plan (the signal), and establishes unified governance using templates. Use this skill when a user asks to map, restructure, reorganize, or apply new governance to an existing messy repository.

12SKILL.mdUpdated Jul 20, 2026

a-organvm/workspace-autopsy-governance

a-organvm/workshop-presentation-design

testing

VerifiedTrustedCommunity

Design engaging workshops, conference talks, and educational presentations. Covers learning objectives, activity design, slide craft, and facilitation techniques. Triggers on workshop design, presentation prep, talk structure, or training session requests.

12SKILL.mdUpdated Jul 20, 2026

a-organvm/workshop-presentation-design

a-organvm/webhook-integration-patterns

development

VerifiedTrustedCommunity

Designs reliable webhook systems with proper delivery guarantees, retry logic, signature verification, and idempotent processing for event-driven integrations.

12SKILL.mdUpdated Jul 20, 2026

a-organvm/webhook-integration-patterns

Download

For Claude Desktop. Download once, then upload the file in the app — no terminal needed.

Need help? View full Cowork setup guide →

Install manually

Choose your platform

# Clone the repo
git clone https://github.com/a-organvm/a-i--skills.git

# Copy into Claude Code skills folder (global)
cp -r a-i--skills/distributions/claude/skills/browser-extension-patterns ~/.claude/skills/

Claude Code Skills — official skills path docs.

Repository

a-organvm/a-i--skills

6 stars

Compatible with

Claude Code

OpenAI Codex CLI

ChatGPT