Opuspad

OpusPad: A local-first, WYSIWYG Markdown editor for Chrome, built for the AI era


Value Proposition

OpusPad transforms your Chrome browser into a robust local file editor with a Notion-like WYSIWYG experience. Seamlessly edit Markdown files (like CLAUDE.md, specs, or READMEs) stored on your local disk, without needing to open a full IDE or rely on cloud services.

**🌐 Website:** [editor.dull.business](https://editor.dull.business)

Why OpusPad?

• Local-First: Your files stay on your disk. No cloud storage, no unnecessary uploads.
• WYSIWYG & Source Mode: Enjoy a beautiful Notion-like editing experience, or switch to the raw Markdown source mode when needed.
• AI-Ready: Perfect for managing and editing AI-generated content and specifications, like CLAUDE.md files, directly where you work.
• Chrome Integrated: Leverages the native File System Access API for direct local file manipulation.
• Lightweight: No need for heavy IDEs just to edit a few Markdown files.

Installation

1. Chrome Web Store (Recommended)

Install OpusPad directly from the [Chrome Web Store](https://chromewebstore.google.com/detail/opuspad/ephlhjlnpnjjnjgdohdnbknadhklcoag).

2. Developer Setup (for local development)

1. Clone the repository: git clone https://github.com/luanjunyi/opuspad.git
2. Navigate to the directory: cd opuspad
3. Install dependencies: npm install
4. Build the extension: npm run build (This will generate a dist/ directory)
5. Load into Chrome:
   • Open Chrome and navigate to chrome://extensions/.
   • Enable "Developer mode".
   • Click "Load unpacked" and select the dist/ directory.

Use Cases

• Editing CLAUDE.md files for AI agent instructions.
• Managing local specification documents.
• Quickly updating README.md files.
• Any task requiring local Markdown file editing within Chrome.

Privacy

OpusPad is truly local-fir