MarkView

MarkView

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Native macOS markdown preview with MCP server for Claude Code. Claude writes markdown — MarkView renders it live, in a real native window, while you work.

Versions: The macOS app (app badge) and the npm MCP wrapper (npm badge) are versioned independently. App releases happen when the Swift binary changes; npm patches happen for MCP server improvements. Both badges always show the latest of each.

Quick Start — Claude Code

One command to wire MarkView into every Claude Code session:

claude mcp add --transport stdio --scope user markview -- npx mcp-server-markview

That's it. Claude can now call preview_markdown to render any markdown string in a native macOS window, or open_file to open any .md file directly.

Claude Desktop Setup

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{

"mcpServers": { "markview": { "command": "npx", "args": ["mcp-server-markview"] } } }

Note: MCP servers belong in ~/.claude.json (Claude Code) or claude_desktop_config.json (Claude Desktop), not ~/.claude/settings.json.

Installation

Homebrew (recommended)

# Full .app with Quick Look extension — Apple notarized, Gatekeeper approved

brew install --cask paulhkang94/markview/markview

CLI only (builds from source)

brew tap paulhkang94/markview brew install markview

Build from source

Prerequisites: macOS 14+, Swift 6.0+ (Xcode Command Line Tools)

git clone https://github.com/paulhkang94/markview.git

cd markview swift build -c release

Install as app (Open With support)

bash scripts/bundle.sh --install

Creates MarkView.app in /Applications and registers it with Launch Services for right-click > Open With in Finder. Refuses (unless you pass --force) if a Dock tile is pinned to a build/ or repo-root MarkView.app path, since both are ephemeral dev output.

Install CLI

bash scripts/install-cli.sh

Creates mdpreview and md symlinks in ~/.local/bin/.

Usage

CLI

mdpreview README.md       # Open a file

mdpreview # Open empty editor

Finder

Right-click any .md, .markdown, .mdown, .mkd file > Open With > MarkView

Programmatic

open -a MarkView README.md

Features

• GitHub Flavored Markdown via swift-cmark (tables, strikethrough, autolinks, task lists, footnotes)
• Mermaid diagrams — flowcharts, sequence, Gantt, ER, and pie charts
• Syntax highlighting via Prism.js (18 languages)
• Quick Look integration — spacebar-preview .md files in Finder without opening the app
• Markdown linting with 9 built-in rules and status bar diagnostics
• Live split-pane editor with WKWebView rendering and bidirectional scroll sync
• File watching with DispatchSource — works with VS Code, Vim, and other editors
• Local image rendering — inlines relative paths like correctly
• Export to HTML and PDF
• HTML sanitizer — strips scripts, event handlers, and XSS vectors
• Drag and drop — drop any .md file onto the window to open
• Find & Replace — Cmd+F / Cmd+Option+F
• Format on save — auto-applies lint fixes
• Auto-save, word count, line numbers, scroll position preservation
• Dark mode — system/light/dark theme options, 18 configurable settings

Architecture

Sources/MarkViewCore/           # Library (no UI, fully testable)

MarkdownRenderer.swift # cmark-gfm C API wrapper FileWatcher.swift # DispatchSource file monitoring MarkdownLinter.swift # 9-rule pure Swift linting engine HTMLSanitizer.swift # XSS prevention LanguagePlugin.swift # Plugin protocol + registry Plugins/ # CSV, HTML, Markdown plugins

Sources/MarkView/ # SwiftUI app (macOS 14+) ContentView.swift # Split-pane editor + preview WebPreviewView.swift # WKWebView with Prism.js ExportManager.swift # HTML/PDF export

Sources/MarkViewMCPServer/ # MCP server for AI tool integration main.swift # stdio JSON-RPC (preview_markdown, open_file)

Tests/TestRunner/ # 403 standalone tests (no XCTest) Tests/VisualTester/ # 5 visual regression tests + WCAG contrast Tests/FuzzTester/ # 10K random input crash testing Tests/DiffTester/ # Differential testing vs cmark-gfm CLI

See docs/ARCHITECTURE.md for full details.

Testing

swift run MarkViewTestRunner    # 403 tests

python3 scripts/verify.py # Full verification (build + tests, writes stamp) python3 scripts/verify.py --extended # + fuzz + differential bash scripts/test-mcp.sh # MCP protocol tests

Development

swift build

swift run MarkView swift run MarkView /path/to/file.md

Support

• GitHub Sponsors
• Star this repo to help others find it

License

MIT — see LICENSE.