Unified Diff MCP Server

Beautiful diff visualization for Claude Desktop. Transform code diffs into stunning visual comparisons with GitHub Gist integration and local file output.

✨ Features

- 🎨 Beautiful HTML diff visualization using diff2html
- 🌐 GitHub Gist integration for instant sharing
- 📁 Local file output (PNG/HTML)
- 🔄 Auto-delete functionality for temporary diffs
- 🖥️ Cross-platform support (Windows, macOS, Linux)
- ⚡ High-performance with Bun runtime
- 🛡️ Enhanced Security with multi-level protection for shared diffs
- 🔒 Multi-level security (Low/Medium/High) for different use cases

🚀 Quick Start

Installing via Smithery

bunx @smithery/cli install @gorosun/unified-diff-mcp --client claude --config '{
  "defaultAutoOpen": true,
  "defaultOutputMode": "html",
  "githubUsername": "your_actual_github_username",
  "githubToken": "ghp_your_actual_token_here"
}'

Manual Installation

1. Install Claude Desktop and Bun
2. Clone and build:

   git clone https://github.com/gorosun/unified-diff-mcp.git

   cd unified-diff-mcp

   bun install

   

🛠️ Tools Overview

| Tool | Purpose | Output | Best For |
|------|---------|--------|----------|
| visualize_diff_html_content | Browser display & sharing | GitHub Gist + HTML preview URL | Quick sharing, instant viewing |
| visualize_diff_output_file | Local file storage | PNG/HTML files | Local storage, presentations |

📖 Usage Examples

🎯 Optimal Prompts by Purpose

| Purpose | Recommended Prompt | Tool Used | Output |
|---------|-------------------|-----------|--------|
| Quick Preview | Please visualize and preview the following diff:<br>以下のdiffを可視化してプレビューしてください | visualize_diff_html_content | GitHub Gist + HTML preview URL |
| Local Storage | Please visualize and save the following diff to a file:<br>以下のdiffを可視化してファイルに保存してください | visualize_diff_output_file | Local HTML/PNG file |
| Share with Others | Please visualize the following diff and create a shareable link:<br>以下のdiffを可視化して共有リンクを作成してください | visualize_diff_html_content | GitHub Gist with shareable URL |
| Image Export | Please visualize and save the following diff as a PNG image:<br>以下のdiffを可視化してPNG画像で保存してください | visualize_diff_output_file | Local PNG image |
| Code Review | Please visualize the following diff in side-by-side format:<br>以下のdiffをside-by-side形式で可視化してください | Either tool | Side-by-side comparison |
| Documentation | Please visualize and save the following diff as an HTML file:<br>以下のdiffを可視化してHTMLファイルで保存してください | visualize_diff_output_file | Local HTML file |
| 🔒 Secure Sharing | Please visualize this diff with high security:<br>以下のdiffを高セキュリティで可視化してください | visualize_diff_html_content | Secret Gist with auto-delete |

Share diff instantly (GitHub Gist)

visualize_diff_html_content:
- Creates temporary GitHub Gist
- Auto-deletes after 30 minutes
- Instant browser-ready URLs
- Perfect for code reviews

Save diff locally

visualize_diff_output_file:
- Saves PNG or HTML to local disk
- Auto-opens in browser (optional)
- Perfect for documentation

🎛️ Configuration

Environment Variables

| Variable | Description | Default |
|----------|-------------|---------|
| GITHUB_TOKEN | GitHub Personal Access Token (for Gist integration) | Required for visualize_diff_html_content |
| DEFAULT_AUTO_OPEN | Auto-open generated files | false |
| DEFAULT_OUTPUT_MODE | Default output format (html or image) | html |

GitHub Token Setup

1. Go to GitHub Settings > Personal Access Tokens
2. Generate new token with gist scope
3. Add to your environment:

   export GITHUB_TOKEN="your_token_here"

   

Claude Desktop Configuration

macOS:

code ~/Library/Application\ Support/Claude/claude_desktop_config.json

Windows:

code %APPDATA%\Claude\claude_desktop_config.json

Configuration template:

{

  "mcpServers": {

    "unified-diff-mcp": {

      "command": "bun",

      "args": ["run", "/path/to/unified-diff-mcp/src/index.ts"],

      "env": {

        "GITHUB_TOKEN": "your_github_token_here",

        "DEFAULT_AUTO_OPEN": "true",

        "DEFAULT_OUTPUT_MODE": "html"

      }

    }

  }

}

📋 Parameters Reference

Common Parameters

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| diff | string | (required) | Unified diff text |
| format | string | side-by-side | Display format (line-by-line or side-by-side) |
| showFileList | boolean | true | Show file list summary |
| highlight | boolean | true | Enable syntax highlighting |
| oldPath | string | file.txt | Original file path |
| newPath | string | file.txt | Modified file path |
| autoOpen | boolean | false | Auto-open in browser |

GitHub Gist Specific

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| expiryMinutes | number | 30 | Auto-delete time (1-1440 minutes) |
| public | boolean | false | Public vs secret gist |

Local File Specific

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| outputType | string | html | Output format (html or image) |

🌍 Platform Support

| Platform | Auto-Open | Commands |
|----------|-----------|----------|
| Windows | ✅ | start (primary), explorer (fallback) |
| macOS | ✅ | open (primary), AppleScript (fallback) |
| Linux | ✅ | xdg-open |

🔧 Development

Development mode (with hot reload):

{

  "command": "bun",

  "args": ["--watch", "/path/to/unified-diff-mcp/src/index.ts"]

}

Production mode:

{

  "command": "bun",

  "args": ["run", "/path/to/unified-diff-mcp/src/index.ts"]

}

📚 Advanced Usage

🔒 Enhanced Security Levels

When GitHub Token isn't available or for secure sharing, you can choose from multiple security levels:

| Security Level | Configuration | Features | Use Cases |
|---------|---------|--------|--------|
| 🟢 Low | Secret Gist + 60min auto-delete | URL-only access | Code examples, learning |
| 🟡 Medium | Secret Gist + Password + 30min auto-delete | URL + Access code required | Team reviews |
| 🔴 High | Secret Gist + Password + 15min auto-delete | URL + Access code + Short duration | Sensitive code |

Usage Example

Please visualize this diff with high security:
--- a/config.js
+++ b/config.js
@@ -1,3 +1,4 @@
 const config = {
-  apiKey: 'old-key'
+  apiKey: 'new-secure-key',
+  timeout: 5000
 };

Response Example:

🔒 Secure Diff Visualization

🔴 Security Level: High Security - Secret Gist + Password (15min auto-delete)

📋 Preview Link: https://htmlpreview.github.io/?...

🔑 Access Code: a7x9k2

⏰ Auto-delete: 15 minutes

🔄 Fallback Functionality

When GitHub Token is unavailable, the system falls back to local files:
- HTML saved as temporary file
- Automatic browser opening
- Security-based file management

For detailed setup and integration guides:

- 🇺🇸 English: CLAUDE_CODE_INTEGRATION.md
- 🇯🇵 日本語: CLAUDE_CODE_INTEGRATION_JP.md

🤝 Supported Clients

- Claude Desktop (Primary)
- Claude Code (CLI)
- VS Code + MCP Extension
- Cline and other MCP clients

📄 License

MIT License - see LICENSE file for details.

Dependencies

| Library | License | Purpose |
|---------|---------|---------|
| diff2html | MIT | HTML diff generation |
| playwright-core | Apache 2.0 | Browser automation |
| @modelcontextprotocol/sdk | MIT | MCP integration |

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Made with ❤️ for the Claude Desktop community