Leaflet MCP Server

A Model Context Protocol (MCP) server that provides comprehensive documentation, code generation, and interactive tools for Leaflet.js - the leading open-source JavaScript library for mobile-friendly interactive maps.

Overview

This MCP server enables AI assistants like Claude to help developers work with Leaflet.js by providing:

• 📚 Complete API Documentation - Full Leaflet API reference and quick start guides

• 🛠️ Code Generation Tools - Generate ready-to-use Leaflet code for common patterns

• 🔍 Smart Search - Find relevant examples and documentation quickly

• 🎨 Plugin Recommendations - Discover and integrate Leaflet plugins

• 🐛 Debugging Help - Solutions for common Leaflet issues

• 🗺️ Interactive Examples - Access to official Leaflet examples with code

Features

Resources

The server exposes four main documentation resources:

1. Leaflet API Reference (leaflet://docs/api-reference)

   • Complete API documentation for all Leaflet classes

   • Methods, options, and events for Map, Marker, TileLayer, Popup, etc.

   • Vector layers (Polyline, Polygon, Circle, Rectangle)

   • GeoJSON, LayerGroup, Controls, Events, and utility functions

2. Quick Start Guide (leaflet://docs/quick-start)

   • Getting started with Leaflet

   • Installation via CDN or npm

   • Basic map setup and initialization

   • Common patterns and troubleshooting

3. All Leaflet Examples (leaflet://examples/all)

   • Collection of official Leaflet examples

   • Mobile-friendly maps, custom icons, GeoJSON

   • Choropleth maps, layer controls, accessibility

   • Performance tips and best practices

4. Plugins Directory (leaflet://plugins/directory)

   • Curated list of 40+ popular Leaflet plugins

   • Organized by category (markers, drawing, visualization, controls, etc.)

   • Installation instructions and code examples

   • Links to GitHub repositories

Tools

The server provides 10 powerful tools for working with Leaflet:

1. create_map

Generate complete Leaflet map initialization code with HTML boilerplate.

Parameters:

• center (required): {lat: number, lng: number} - Map center coordinates

• zoom: Initial zoom level (0-19, default: 13)

• tileProvider: Tile provider - "openstreetmap", "cartodb", or "stamen"

• containerId: HTML element ID (default: "map")

• includeHTML: Include full HTML page (default: true)

Example Use Case:

"Create a map centered on San Francisco at zoom level 12"

2. add_marker

Generate code for adding markers with popups, tooltips, and custom icons.

Parameters:

• position (required): {lat: number, lng: number} - Marker position

• popup: Popup content (HTML supported)

• tooltip: Tooltip text

• draggable: Make marker draggable (default: false)

• customIcon: Include custom icon setup code (default: false)

Example Use Case:

"Add a draggable marker at Golden Gate Bridge with a popup"

3. create_layer

Generate code for creating vector layers (polylines, polygons, circles, rectangles).

Parameters:

• layerType (required): "polyline", "polygon", "circle", "rectangle", or "circleMarker"

• coordinates: Array of {lat, lng} objects (for polylines/polygons)

• center: {lat, lng} for circles/circle markers

• radius: Radius in meters (for circles) or pixels (for circle markers)

• style: Styling options (color, weight, opacity, fillColor, fillOpacity)

• popup: Popup content for the layer

Example Use Case:

"Draw a red polygon around downtown Seattle"

4. add_popup

Generate code for creating and customizing popups.

Parameters:

• content (required): Popup content (HTML supported)

• position: {lat, lng} for standalone popups

• maxWidth: Maximum width in pixels (default: 300)

• attachTo: "marker", "layer", or "latlng" (default: "marker")

Example Use Case:

"Create a popup with an image and button"

5. create_geojson_layer

Generate code for loading and displaying GeoJSON data with custom styling.

Parameters:

• dataSource: "inline", "url", or "variable" (default: "inline")

• includeExample: Include example GeoJSON data (default: true)

• style: Default style object for features

• onEachFeature: Include onEachFeature handler example (default: true)

• filter: Include filter function example (default: false)

Example Use Case:

"Load GeoJSON from a URL and style features by property"

6. create_choropleth

Generate code for creating interactive choropleth (data visualization) maps.

Parameters:

• dataProperty: Property name to visualize from GeoJSON (default: "density")

• colorScheme: "sequential", "diverging", or "qualitative" (default: "sequential")

• steps: Number of color steps (default: 5)

• includeLegend: Include legend control (default: true)

• includeInteraction: Include hover effects and info box (default: true)

Example Use Case:

"Create a population density choropleth map with legend"

7. convert_coordinates

Convert between different coordinate formats and validate coordinates.

Parameters:

• input (required): Coordinates in any common format

• outputFormat: "decimal", "dms", "leaflet", or "geojson" (default: "leaflet")

Supported Input Formats:

• Decimal degrees: 51.505, -0.09

• Array format: [51.505, -0.09]

• DMS: 51°30'18"N 0°5'24"W

Example Use Case:

"Convert 40.7128° N, 74.0060° W to Leaflet format"

8. suggest_plugin

Get recommendations for Leaflet plugins based on functionality or category.

Parameters:

• functionality: What you're looking for (e.g., "heatmap", "clustering", "routing")

• category: "markers", "overlays", "vector", "data", "controls", "interaction", "animation", or "tile"

Example Use Case:

"Find a plugin for marker clustering"
"Suggest plugins for drawing shapes"

9. search_examples

Search through official Leaflet examples for specific functionality.

Parameters:

• query (required): Search term (e.g., "mobile", "geojson", "choropleth")

• includeCode: Include code snippets in results (default: true)

Example Use Case:

"Show me examples of custom marker icons"
"Find examples for mobile geolocation"

10. debug_common_issues

Get help debugging common Leaflet problems.

Parameters:

• issue (required): Issue type

  • "map-not-showing"

  • "tiles-not-loading"

  • "markers-not-appearing"

  • "icons-broken"

  • "popup-not-working"

  • "controls-missing"

  • "other"

• description: Detailed description of the problem

Example Use Case:

"Why is my map not showing?"
"Help fix broken marker icons in webpack"

Installation

As an MCP Server

1. Clone or download this repository:

   git clone <repository-url>
   cd leaflet-mcp-server

2. Install dependencies:

   npm install

3. Build the server:

   npm run build

4. Configure your MCP client (e.g., Claude Desktop):

   Add to your MCP settings file:

   macOS/Linux: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json

   {
     "mcpServers": {
       "leaflet": {
         "command": "node",
         "args": ["/absolute/path/to/leaflet-mcp-server/build/index.js"]
       }
     }
   }

5. Restart your MCP client to load the server.

Development Mode

Watch for changes during development:

npm run watch

Usage Examples

Once configured, you can ask your AI assistant questions like:

Getting Started

• "Create a basic Leaflet map centered on Tokyo"

• "Show me how to add a marker with a popup"

• "How do I initialize a Leaflet map?"

Working with Data

• "Load GeoJSON data from a URL and display it on the map"

• "Create a choropleth map showing population density"

• "How do I style GeoJSON features based on properties?"

Customization

• "Add a draggable marker with a custom icon"

• "Draw a circle with a 500-meter radius around a point"

• "Create a polygon and add a popup to it"

Finding Solutions

• "Why aren't my map tiles loading?"

• "Find a plugin for clustering markers"

• "Show me examples of custom marker icons"

• "Convert these GPS coordinates to Leaflet format"

Advanced Features

• "How do I create a heatmap in Leaflet?"

• "Find plugins for drawing and editing shapes"

• "Show me how to use layer controls"

Architecture

Project Structure

leaflet-mcp-server/
├── src/
│   ├── index.ts        # Main MCP server implementation
│   ├── tools.ts        # Code generation tool implementations
│   ├── docs.ts         # API reference and quick start documentation
│   ├── examples.ts     # Official Leaflet examples collection
│   └── plugins.ts      # Curated plugins directory
├── build/              # Compiled JavaScript (generated)
├── package.json        # Project metadata and dependencies
├── tsconfig.json       # TypeScript configuration
└── README.md          # This file

Technical Details

• Language: TypeScript compiled to ES2022

• Module System: ES Modules (Node16)

• MCP SDK: @modelcontextprotocol/sdk v1.0.4+

• Runtime: Node.js (requires ES2022 support)

• Transport: stdio (standard input/output)

How It Works

1. Server Initialization:

   • The server starts and listens on stdio

   • Registers resources (documentation) and tools (code generators)

   • Waits for requests from MCP clients

2. Resource Access:

   • Clients can read documentation resources via URI scheme (leaflet://)

   • Resources return formatted markdown content

   • Content includes code examples and API references

3. Tool Execution:

   • Clients invoke tools with structured parameters

   • Tools generate appropriate Leaflet code based on parameters

   • Results include code snippets with explanations and next steps

4. Communication:

   • All communication uses the Model Context Protocol

   • Requests and responses are JSON-RPC formatted

   • Server is stateless - each request is independent

API Documentation

Resource URIs

Tool Schemas

All tools follow the MCP tool schema format with:

• name: Tool identifier

• description: What the tool does

• inputSchema: JSON Schema for parameters

See the Tool Details section above for complete parameter documentation.

Development

Prerequisites

• Node.js 16+ (with ES2022 support)

• npm or yarn

• TypeScript knowledge (optional, for modifications)

Building from Source

# Install dependencies
npm install

# Build once
npm run build

# Watch mode (auto-rebuild on changes)
npm run watch

# Prepare for distribution
npm run prepare

Adding New Tools

1. Add tool implementation in src/tools.ts:

   export function myNewTool(args: any): string {
     // Implementation
     return formattedResult;
   }

2. Register tool in src/index.ts:

   // In ListToolsRequestSchema handler
   {
     name: "my_new_tool",
     description: "What this tool does",
     inputSchema: { /* JSON Schema */ }
   }
   
   // In CallToolRequestSchema handler
   case "my_new_tool": {
     const result = myNewTool(args);
     return { content: [{ type: "text", text: result }] };
   }

3. Rebuild and test:

   npm run build

Adding New Resources

1. Add content in appropriate file (src/docs.ts, src/examples.ts, etc.)

2. Register in src/index.ts:

   // In ListResourcesRequestSchema handler
   {
     uri: "leaflet://my/resource",
     mimeType: "text/plain",
     name: "Resource Name",
     description: "Resource description"
   }
   
   // In ReadResourceRequestSchema handler
   if (uri === "leaflet://my/resource") {
     return {
       contents: [{
         uri,
         mimeType: "text/plain",
         text: MY_RESOURCE_CONTENT
       }]
     };
   }

Common Use Cases

Web Development

• Quickly scaffold new map applications

• Add interactive mapping features to existing sites

• Prototype location-based features

• Learn Leaflet API through examples

Data Visualization

• Create choropleth maps for data analysis

• Display geographic datasets

• Build dashboards with embedded maps

• Visualize spatial data from GeoJSON

Mobile Development

• Implement mobile-friendly maps

• Add geolocation features

• Optimize for touch interactions

• Build responsive map interfaces

Education & Learning

• Learn Leaflet.js through guided examples

• Understand mapping concepts

• Explore plugin ecosystem

• Debug common issues

Troubleshooting

Server Not Connecting

Problem: MCP client can't connect to the server

Solutions:

1. Verify the path in your MCP config is absolute and correct

2. Ensure the build directory exists: npm run build

3. Check that Node.js is in your PATH

4. Look for errors in your MCP client logs

5. Restart your MCP client after configuration changes

Build Errors

Problem: npm run build fails

Solutions:

1. Delete node_modules and build directories

2. Run npm install again

3. Check Node.js version: node --version (need 16+)

4. Ensure TypeScript is installed correctly

Tool Not Working

Problem: Tool returns unexpected results

Solutions:

1. Check parameter types match the schema

2. Verify required parameters are provided

3. Look for error messages in tool output

4. Try with minimal parameters first

Documentation Not Loading

Problem: Resource content is empty or incorrect

Solutions:

1. Rebuild the server: npm run build

2. Check that source files in src/ are unchanged

3. Verify URI syntax in requests

Resources

Leaflet Documentation

• Official Site: https://leafletjs.com/

• API Reference: https://leafletjs.com/reference.html

• Examples: https://leafletjs.com/examples.html

• Plugins: https://leafletjs.com/plugins.html

Model Context Protocol

• Documentation: https://modelcontextprotocol.io/

• Specification: https://spec.modelcontextprotocol.io/

• SDK Reference: https://github.com/modelcontextprotocol/sdk

Community

• Leaflet GitHub: https://github.com/Leaflet/Leaflet

• Stack Overflow: leaflet tag

• GIS Stack Exchange: leaflet tag

• Awesome Leaflet: https://github.com/tomik23/awesome-leaflet

Contributing

Contributions are welcome! Here are ways to help:

1. Report Issues: Found a bug or have a suggestion? Open an issue

2. Add Tools: Implement new code generation tools

3. Improve Documentation: Enhance inline docs and examples

4. Add Plugin Info: Suggest additional plugins for the directory

5. Share Use Cases: Tell us how you're using this server

License

MIT License - see LICENSE file for details

Acknowledgments

• Leaflet.js - Created by Vladimir Agafonkin and maintained by the open-source community

• Model Context Protocol - Developed by Anthropic

• Plugin Authors - Thanks to all Leaflet plugin maintainers

• OpenStreetMap - For providing free map data

Version History

1.0.0 (Current)

• Initial release

• 10 code generation tools

• 4 documentation resources

• Complete API reference

• 40+ plugin recommendations

• Official examples collection

• Common issue debugger

Built with ❤️ for the Leaflet and MCP communities

For questions, issues, or feedback, please open an issue on GitHub.