OpusPad

Review and edit local Markdown files in Chrome. WYSIWYG + source mode. 100% private, zero uploads. Built for AI-indigenous builders.

If you use AI coding agents like Claude Code or Cursor, you constantly deal with generated Markdown: CLAUDE.md, implementation plans, architecture notes, and specs. Opening these raw files in the browser is an unreadable mess. Opening them in a heavy desktop app just for a quick review is overkill. OpusPad is the sweet spot. A lightweight Chrome extension that opens your local Markdown files and renders them beautifully. KEY FEATURES: • WYSIWYG Editor — Tables, code blocks, and lists render cleanly. Edit text naturally without worrying about Markdown syntax. • Source Mode — Toggle to raw Markdown with full syntax highlighting for precision edits. A compatibility guard automatically falls back to source mode for complex syntax. • Directory Sidebar — Browse your project's file tree. Smart fuzzy search lets you jump to any file instantly. • Auto Save — Your edits persist to disk automatically. No manual save required. • External Change Detection — When an AI agent updates a file on disk, OpusPad detects it and reloads automatically. • File Management — Create new Markdown files and delete old ones directly from the sidebar. • 100% Local & Private — Your files never leave your machine. Zero telemetry, zero cloud sync, zero data collection. • Lightweight — No Electron overhead. Runs natively inside Chrome. Opens instantly. PERFECT FOR: - Reviewing CLAUDE.md and agent rulesets - Editing architecture plans and specs - Quick README updates - Refining any AI-generated documentation OpusPad is free and open source.