MCP Apps Starter Kit

I built these 2 mini mcp apps for my own daily use inside Claude Desktop — tracking workouts, planning trips, budgeting, comparing products, and making decisions. They turned out to be genuinely useful, so I'm putting them out here for anyone to explore, remix, or use as a starting point for their own MCP Apps.

Each app renders as a real interactive UI right inside Claude's chat — not just text, but React components with charts, forms, progress tracking, and two-way communication with Claude. If you've ever wished Claude could show you something visual instead of just describing it, this is what that looks like.

Built with the MCP Apps SDK.

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The 5 Apps

Workout Tracker

"Give me a 4-week strength training plan"

This is the app I've spent the most time on — it's the most feature-rich and thoroughly tested of the five. It demonstrates what's really possible with MCP Apps:

Dark theme with a clean zinc + blue palette
Expandable exercise cards with form cues, sets/reps, and muscle group indicators
Progress tracking — check off exercises, log actual weights/reps, save to disk
Persistent history — saved to ~/.claude-workout-log.json, with automatic dedup
Video references — auto-fetches YouTube form guides and opens them via app.openLink()
Batch modifications — tweak multiple exercises, send all changes to Claude at once
Bidirectional chat — the app talks back to Claude to modify plans, request videos, or regenerate

Trip Planner

"I'm in Mumbai and want a 5-day vacation with a ₹50,000 budget — show me some options"

A two-phase trip planning experience. Phase 1 (Trip Explorer) shows 3-5 destination options side by side with:

Distance + travel modes — km away, with flight/train/drive durations from your city
Weather — expected temperature range and conditions
Budget fit — color-coded against your budget (green/yellow/red)
Adjustable sliders — change budget or trip duration, hit "Refresh options" to regenerate
Multi-select — pick up to 2 destinations to compare detailed itineraries side by side
Currency support — INR, USD, EUR, etc. with proper formatting

Phase 2 (Itinerary) renders a day-by-day plan where you can:

Swap or remove individual activities with one tap
Comment on any activity with specific feedback
Adjust trip style — quick chips like "More relaxed", "Foodie focus", or type your own
Queue changes and send them all to Claude at once to regenerate

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The following 3 apps are work-in-progress — they render and are functional, but haven't been as heavily tested or polished. Feel free to try them out and iterate on them.

Budget Planner (WIP)

"Help me plan a $5K monthly budget"

Pie chart + bar chart breakdown of spending categories with surplus/deficit tracking. I use this whenever I want to sanity-check how I'm allocating money across categories.

Product Comparison (WIP)

"Compare MacBook Air M3 vs ThinkPad X1 Carbon"

Side-by-side cards with pros/cons, star ratings, and a "Best Pick" badge. Great for any time you're weighing two or more options — laptops, tools, services, whatever.

Decision Matrix (WIP)

"Help me decide between 3 apartments"

Weighted criteria table with heatmap-style scoring and automatic rankings. I use this for any multi-factor decision — it forces you to think about what actually matters.

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Screenshots

Coming soon — I'll add screenshots showing each app running inside Claude Desktop so you can see what these look like in practice before you install them.

To add your own screenshots:

Take a screenshot of each app in Claude Desktop
Save them in a screenshots/ folder
Uncomment the image lines in this README

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Quick Start

# Clone
git clone https://github.com/rushildharhakim/mcp-apps-starter-kit.git
cd mcp-apps-starter-kit

# Install & build
npm install --legacy-peer-deps
npm run build

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

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "starter-kit": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-apps-starter-kit/dist/server.js"]
    }
  }
}

Restart Claude Desktop. Try any of the example prompts above.

How It Works

You type a prompt → Claude calls a render_* tool → MCP server returns structured data + UI
                                                          ↓
                                                 Claude Desktop loads the HTML view
                                                          ↓
                                                 React app renders in a sandboxed iframe
                                                          ↓
                                                 You interact → app talks back to Claude

Each view is a self-contained React app bundled into a single HTML file via Vite + vite-plugin-singlefile. The MCP server registers both a tool (to receive structured data from Claude) and a resource (to serve the HTML view to Claude Desktop).

Key SDK Patterns

| API | What it does | |-----|-------------| | registerAppTool() | Registers a tool that returns structuredContent + links to a UI resource | | registerAppResource() | Serves the HTML view file to Claude Desktop | | useApp() + ontoolresult | React hook to receive tool result data in the iframe | | app.callServerTool() | Calls MCP server tools from the iframe (e.g., save workout log) | | app.sendMessage() | Injects a message into Claude's conversation from the iframe | | app.openLink() | Opens external URLs in the default browser (bypasses iframe sandbox) |

File Structure

mcp-apps-starter-kit/
  src/
    server.ts                          # MCP server — 6 tools + 6 resources + 2 utility tools
    views/
      shared/styles.ts                 # Inline style helpers
      BudgetView.tsx                   # Pie + bar charts (Recharts)
      ComparisonView.tsx               # Side-by-side comparison grid
      TripExplorerView.tsx             # Destination comparison + selection (Phase 1)
      TripPlannerView.tsx              # Interactive day-by-day itinerary (Phase 2)
      WorkoutPlanView.tsx              # Interactive workout tracker
      DecisionMatrixView.tsx           # Weighted decision matrix + heatmap
      *.html                           # Entry points for each view
  package.json
  tsconfig.json
  vite.config.ts

Tech Stack

MCP SDK: @modelcontextprotocol/sdk + @modelcontextprotocol/ext-apps
React 19 with inline styles (no CSS framework needed in sandboxed iframes)
Recharts for pie/bar/line charts
Vite + vite-plugin-singlefile for bundling views into self-contained HTML
TypeScript for the server, JSX for views

License

MIT

MCP Apps Starter Kit