ext-apps/examples/map-server

Example: Interactive Map

Interactive 3D globe viewer using CesiumJS with OpenStreetMap tiles. Demonstrates geocoding integration and full MCP App capabilities.

MCP Client Configuration

Add to your MCP client configuration (stdio transport):

{
  "mcpServers": {
    "map": {
      "command": "npx",
      "args": [
        "-y",
        "--silent",
        "--registry=https://registry.npmjs.org/",
        "@modelcontextprotocol/server-map",
        "--stdio"
      ]
    }
  }
}

Local Development

To test local modifications, use this configuration (replace ~/code/ext-apps with your clone path):

{
  "mcpServers": {
    "map": {
      "command": "bash",
      "args": ["-c", "cd ~/code/ext-apps/examples/map-server && npm run build >&2 && node dist/index.js --stdio"]
    }
  }
}

Features

• 3D Globe Rendering: Interactive CesiumJS globe with rotation, zoom, and 3D perspective
• Geocoding: Search for places using OpenStreetMap Nominatim (no API key required)
• OpenStreetMap Tiles: Uses free OSM tile server (no Cesium Ion token needed)
• Dynamic Loading: CesiumJS loaded from CDN at runtime for smaller bundle size

Running

1. Install dependencies:

   npm install
   

2. Build and start the server:

   npm run start:http  # for Streamable HTTP transport
   # OR
   npm run start:stdio  # for stdio transport
   

3. View using the basic-host example or another MCP Apps-compatible host.

Tools

geocode

Search for places by name or address. Returns coordinates and bounding boxes.

{
  "query": "Eiffel Tower"
}

Returns up to 5 matches with lat/lon coordinates and bounding boxes.

show-map

Display the 3D globe zoomed to a bounding box.

{
  "west": 2.29,
  "south": 48.85,
  "east": 2.3,
  "north": 48.86,
  "label": "Eiffel Tower"
}

Defaults to London if no coordinates provided.

Architecture

Server (server.ts)

Exposes two tools:

• geocode - Queries OpenStreetMap Nominatim API with rate limiting
• show-map - Renders the CesiumJS globe UI at a specified location

Configures Content Security Policy to allow fetching tiles from OSM and Cesium CDN.

App (src/mcp-app.ts)

Vanilla TypeScript app that:

• Dynamically loads CesiumJS from CDN
• Initializes globe with OpenStreetMap imagery (no Ion token)
• Receives tool inputs via the MCP App SDK
• Handles camera navigation to specified bounding boxes

Key Files

• server.ts - MCP server with geocode and show-map tools
• mcp-app.html / src/mcp-app.ts - CesiumJS globe UI
• server-utils.ts - HTTP server utilities

Notes

• Rate limiting is applied to Nominatim requests (1 request per second per their usage policy)
• The globe works in sandboxed iframes with appropriate CSP configuration
• No external API keys required - uses only open data sources