<domain_overview>

🌐 BROWSER EXTENSION: THE 2026 MASTERCLASS

Philosophy: Extensions are ephemeral, restricted, yet powerful. Persistence is an Art. Security is a Mandate. Design Constraint: For UI/UX, Aesthetics, and Layout, YOU MUST REFER TO THE frontend-design SKILL. PERSISTENCE PARADOX GUARD (CRITICAL): Never rely on global variables or in-memory state in background scripts. AI-generated code frequently fails by assuming Manifest V3 service workers are persistent. They are NOT; they terminate after 30 seconds of inactivity. You MUST backup every piece of state to chrome.storage or IndexedDB immediately upon change. This skill aims to eliminate "volatile-state" bugs typical of generic AI implementations. If data is not in durable storage, it does not exist. </domain_overview> <manifest_architecture>

🏗️ PROTOCOL 1: THE MANIFEST V3 CONSTITUTION

All extensions must be built on Manifest v3. No exceptions.

1. Manifest Blueprint:
   • Service Workers: No persistent background pages. Use "background": { "service_worker": "background.js" }.
   • No Remote Code: All scripts must be local. unsafe-eval is forbidden.
   • Permissions: Principle of Least Privilege. Use optional_permissions where possible.
   • Action UI: Prefer action over browser_action or page_action.
2. Side Panel Supremacy:
   • Requirement: Use chrome.sidePanel for persistent, non-intrusive experiences.
   • API: chrome.sidePanel.setOptions({ path: 'sidepanel.html', enabled: true }). </manifest_architecture> <persistence_engine>

⚡ PROTOCOL 2: THE PERSISTENCE ENGINE (ANTI-TERMINATION)