jesselumarie/mcp-icon-test-server

MCP Icon Test Server

This is a streamable HTTP/SSE MCP server created to test icon support for PR #778 in the MCP Inspector.

Features

This server demonstrates icon metadata for all supported MCP types:

• Server Implementation: The server itself has an icon (⭐)
• Tools: test_tool - A simple echo tool with an icon
• Resources: test://resource/example - A test resource with an icon
• Prompts: test_prompt - A test prompt with an icon

All icons use the same emoji data URI (star emoji) for testing purposes.

Installation

npm install
npm run build

Running the Server

Development mode (with TypeScript):

npm run dev

The server will start on http://localhost:3001

Production mode (compiled):

npm start

Custom port:

PORT=8080 npm run dev

Endpoints

• SSE Endpoint: http://localhost:3001/sse - MCP communication endpoint
• Health Check: http://localhost:3001/health - Server health status
• Message Endpoint: http://localhost:3001/message - Client message POST endpoint

Testing with MCP Inspector

To test this server with the MCP Inspector from PR #778:

1. Start this server: npm run dev
2. In the MCP Inspector, add an HTTP server connection using:

   http://localhost:3001/sse
   

Testing Icon Support

Once connected to the Inspector, you should see icons displayed for:

1. The server itself (in the server list/header)
2. The test_tool tool (in the tools list)
3. The test://resource/example resource (in the resources list)
4. The test_prompt prompt (in the prompts list)

Icon Format

Icons follow the SEP-973 specification with the following structure:

{
  src: string,        // Data URI or HTTP(S) URL
  mimeType: string,   // MIME type (e.g., "image/svg+xml")
  sizes: string[]     // Array of sizes (e.g., ["any", "48x48"])
}

This server uses a simple SVG data URI with a star emoji (⭐) for all icons.

Testing Different Icon Types

You can modify src/index.ts to test different icon formats:

• Different emoji: Change the emoji character in the SVG
• PNG data URI: Use a base64-encoded PNG instead
• HTTP URL: Point to an actual image URL
• Multiple sizes: Provide multiple icon objects in the icons array

Server Capabilities

Tools

• test_tool: Echoes back a message

Resources

• test://resource/example: Returns a simple text resource

Prompts

• test_prompt: Creates a prompt asking about a topic