# MarkViewer

> A native macOS app for reviewing AI-generated Markdown documents — specs, notes, and working docs. Annotate inline, hand off to Claude, ChatGPT, Cursor, or any AI assistant in one keystroke. 100% offline. Free.

## What is MarkViewer?

MarkViewer is a free, lightweight review app for AI-generated Markdown documents on macOS. It is purpose-built for reviewing specs, notes, changelogs, and working documents produced by AI tools like Claude, ChatGPT, Cursor, GitHub Copilot, and Codex CLI.

Unlike editors or IDEs, MarkViewer focuses on the review step: read what AI wrote, annotate what needs changing, and hand off a structured prompt to get it fixed — all without leaving the app or switching browser tabs.

Built with Tauri. Universal Binary (Intel + Apple Silicon). Single developer: Seungbin Baik. Current version: 1.6.4.

## Core Workflow: AI Review Loop

1. Open an AI-generated Markdown file (spec, note, doc)
2. Read with auto table of contents for navigation
3. Highlight any passage → press Cmd+Shift+R to leave an inline annotation
4. Press Cmd+Shift+Enter to open an editable prompt panel (file + all annotations bundled)
5. Copy the prompt → paste into Claude, ChatGPT, Cursor, or any AI tool
6. Receive updated file → MarkViewer auto-detects the change and shows a diff for review

MarkViewer never contacts any AI service directly. It's a local handoff — no API key, no internet required.

## Key Features

- **AI Review Loop** — Annotate passages inline (Cmd+Shift+R), bundle into an editable prompt (Cmd+Shift+Enter), hand off to any AI assistant. Annotations are stored as HTML comments in the Markdown source.
- **AI-assisted Diff View** — Auto-detects external file changes (from Claude Code, Cursor, GitHub Copilot) and shows a diff banner: Review, Accept, or Dismiss.
- **Auto Table of Contents** — Navigate long AI-generated documents instantly. Resizable panel (20-70%) with layout persistence.
- **Multi-tab & Multi-window** — Open multiple AI-generated files in tabs (Cmd+T), new windows (Cmd+N)
- **WYSIWYG Editing** — Quick inline edits without switching to a code editor
- **Search Highlighting** — Find text across AI-generated docs with visual highlights and match navigation
- **GitHub Flavored Markdown** — Tables, task lists, code blocks with syntax highlighting, Mermaid diagrams
- **File Finder & Built-in Terminal** — Browse and run commands without leaving the app
- **100% Offline** — No internet required, no cloud sync, files stay on your device
- **Lightweight & Fast** — Launches instantly, minimal resource usage
- **Native macOS App** — Universal Binary for Intel and Apple Silicon

## Use Cases

### Reviewing AI-Generated Specs and Notes
When Claude, ChatGPT, or any AI tool generates a spec, design doc, or set of notes in Markdown, open it in MarkViewer for a clean, structured review. Use the table of contents to navigate sections, annotate what needs fixing, and hand off corrections in one step.

### AI Coding Agent Workflow
When AI coding agents (Claude Code, Cursor, GitHub Copilot) modify your Markdown files, MarkViewer detects the changes and shows a diff for review. Accept, dismiss, or annotate further using the AI Review Loop.

### GitHub Release Notes
Download release notes as .md files and review them in MarkViewer for a formatted reading experience with table of contents.

### Technical Documentation Review
Preview and review Markdown documents with accurate GFM rendering and WYSIWYG editing.

## Platform

- macOS 10.13 (High Sierra) or later
- Universal Binary (Intel & Apple Silicon)
- macOS only — not available on Windows or Linux

## Download

Website: https://markviewer.com
GitHub Releases: https://github.com/SeungbinBaik/markviewer-releases/releases

## Guides

How to open MD files on Mac: https://markviewer.com/how-to-open-md-file-mac
Markdown viewer for Mac: https://markviewer.com/markdown-preview-mac
GitHub release viewer: https://markviewer.com/github-release-viewer

## Pricing

Free. No paid tiers, no subscriptions, no hidden costs.

## Privacy

100% local processing. No cloud sync, no accounts, no data collection. Files never leave your computer.

## Frequently Asked Questions

### What is MarkViewer for?
MarkViewer is a review app for AI-generated Markdown documents. It's built for the workflow where AI tools (Claude, ChatGPT, Cursor) write specs, notes, and docs, and you need to review, annotate, and iterate on them.

### Is MarkViewer free?
Yes, completely free with no premium features or subscriptions.

### Does MarkViewer work offline?
Yes, 100% offline. All files are processed locally.

### What is the AI Review Loop?
A workflow for reviewing AI-generated docs: annotate passages inline (Cmd+Shift+R), bundle the file and annotations into an editable prompt (Cmd+Shift+Enter), copy it, and paste into your preferred AI tool. MarkViewer never contacts any AI service — it's a local handoff.

### Which AI tools does the review loop support?
Any AI tool that accepts pasted text. Verified with Claude, ChatGPT, Cursor, GitHub Copilot Chat, Google Gemini, Codex CLI, and local LLM UIs.

### Does MarkViewer send my files to Anthropic or OpenAI?
No. MarkViewer generates the prompt locally and copies it to your clipboard on explicit click. You decide where to paste it.

### Can MarkViewer detect external file changes?
Yes. When an AI coding agent modifies your file, MarkViewer shows a diff banner so you can review, accept, or dismiss.

### How is MarkViewer different from VS Code or Obsidian?
MarkViewer is purpose-built for reviewing, not editing or note-taking. It launches instantly, shows a table of contents for navigation, and includes the AI Review Loop for structured feedback to AI tools. No workspace setup, no plugins, no configuration.

## Contact

Email: seungbin.baik@gmail.com
Website: https://markviewer.com