kotlin-sdk/samples/kotlin-mcp-server

MCP Kotlin Server Sample

A sample implementation of an MCP (Model Communication Protocol) server in Kotlin that demonstrates different server configurations and transport methods for both JVM and WASM targets.

Features

• Multiple server operation modes:
  • Standard I/O server (JVM only)
    • SSE (Server-Sent Events) server with plain configuration (JVM, WASM)
    • SSE server using Ktor plugin (JVM, WASM)
• Multiplatform support
• Built-in capabilities for:
  • Prompts management
  • Resources handling
  • Tools integration

Getting Started

Running the Server

You can run the server on the JVM or using Kotlin/WASM on Node.js.

JVM:

To run the server on the JVM (defaults to SSE mode with Ktor plugin on port 3001):

./gradlew runJvm

WASM:

To run the server using Kotlin/WASM on Node.js (defaults to SSE mode with Ktor plugin on port 3001):

./gradlew wasmJsNodeDevelopmentRun

Connecting to the Server

For servers on JVM or WASM:

1. Start the server
2. Use the MCP inspector to connect to http://localhost:<port>/sse

Server Capabilities

• Prompts: Supports prompt management with list change notifications
• Resources: Includes subscription support and list change notifications
• Tools: Supports tool management with list change notifications

Implementation Details

The server is implemented using:

• Ktor for HTTP server functionality
• Kotlin coroutines for asynchronous operations
• SSE for real-time communication
• Standard I/O for command-line interface
• Common Kotlin code shared between JVM and WASM targets