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kotlin-sdk/samples/kotlin-mcp-server
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Filename Latest commit message Latest commit date
Maria Tigina d86813636e
 Introduce server sessions (#198) 
Introduce a `ServerSession` to manage multiple connections to the mcp
server. `Protocall` logic of the `Server` was moved to `ServerSession`,
while MCP resources logic remained in `Server`

## Motivation and Context
1. Fix the multiple connection issues reported for SSE transport
2. Avoid server duplications during configurations: currently every connection
creates a session, but the server stays single

## How Has This Been Tested?

Added `SseIntegrationTest` and `WebSocketIntegrationTest` integration
tests to check connection with single and multiple clients

## Breaking Changes

This change caused several depreciations:
1. The `Server` -> `Protocol` inheritance (which caused single
connection issue) should be removed in future releases, now, all the
methods inherited from `Protocall` marked as `Deprecated` with a
`Warning`
2. Websocket Ktor server initialization changes in order not to create
server instance per connection

## Types of changes

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

---------

Co-authored-by: devcrocod <devcrocod@gmail.com>
2025-09-29 10:10:07 +03:00
..
src Introduce server sessions (#198) 2025-09-29 10:10:07 +03:00
build.gradle.kts #196 Update build configuration and workflows for enhanced local publ… (#275) 2025-09-16 21:43:50 +03:00
README.md add ios and wasm targets (#81) 2025-05-29 05:01:50 +00:00
settings.gradle.kts #196 Update build configuration and workflows for enhanced local publ… (#275) 2025-09-16 21:43:50 +03:00

README.md

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