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kotlin-sdk/samples/kotlin-mcp-server
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Filename Latest commit message Latest commit date
Pavel Gorgulov 21393e7ce3
 New MCP Schema types (#386) 
Implement the last version of the mcp schema and complete restructuring
of the mcp schema implementation from a monolithic `types.kt` file into
separate files.

- #158 
- #185 
- #353 
- #298 
- #248 

## Motivation and Context
The previous implementation of the mcp schema was outdated and contained
several issues. In addition, it stored all mcp types in a single large
file, which made maintenance and further development more difficult

## How Has This Been Tested?
All tests passed

## Breaking Changes
Yes. The new types are now located in a separate package. Additionally,
many types have new parameters and modified constructors

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

## Checklist
- [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
to adopt the new structure:
**Before:**
```kotlin
  import io.modelcontextprotocol.kotlin.sdk.InitializeRequest
  import io.modelcontextprotocol.kotlin.sdk.Resource
```

**After:**
```kotlin
  import io.modelcontextprotocol.kotlin.sdk.types.InitializeRequest
  import io.modelcontextprotocol.kotlin.sdk.types.Resource
```
2025-11-11 12:25:23 +01:00
..
gradle Bump version to 0.8.0-SNAPSHOT and update mcp-kotlin dependency in samples (#385) 2025-11-11 10:56:45 +02:00
src New MCP Schema types (#386) 2025-11-11 12:25:23 +01:00
build.gradle.kts Update Kotlin-MCP-Server with STDIO support, logging & CORS (#371) 2025-11-06 18:18:04 +02:00
gradle.properties #302 Update samples build workflow (#330) 2025-10-23 13:02:22 +03:00
gradlew #302 Update samples build workflow (#330) 2025-10-23 13:02:22 +03:00
gradlew.bat #302 Update samples build workflow (#330) 2025-10-23 13:02:22 +03:00
mcp-inspector-config.json Update Kotlin-MCP-Server with STDIO support, logging & CORS (#371) 2025-11-06 18:18:04 +02:00
README.md Update Kotlin-MCP-Server with STDIO support, logging & CORS (#371) 2025-11-06 18:18:04 +02:00
settings.gradle.kts #302 Update samples build workflow (#330) 2025-10-23 13:02:22 +03:00

README.md

MCP Kotlin Server Sample

A sample implementation of an MCP (Model Context Protocol) server in Kotlin that demonstrates different server configurations and transport methods.

Features

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

Getting Started

Running the Server

The server defaults STDIO transport.

You can customize the behavior using command-line arguments. Logs are printed to ./build/stdout.log

Standard I/O mode (STDIO):

./gradlew clean build

Use the MCP inspector to connect to MCP via STDIO (Click the "▶️ Connect" button):

npx @modelcontextprotocol/inspector --config mcp-inspector-config.json --server stdio-server

SSE with plain configuration:

NB!: 🐞 This configuration may not work ATM

./gradlew run --args="--sse-server 3001"

or

./gradlew clean build
java -jar ./build/libs/kotlin-mcp-server-0.1.0-all.jar --sse-server 3001

Use the MCP inspector to connect to http://localhost:3002/ via SSE Transport (Click the "▶️ Connect" button):

npx @modelcontextprotocol/inspector --config mcp-inspector-config.json --server sse-server

SSE with Ktor plugin:

./gradlew run --args="--sse-server-ktor 3002"

or

./gradlew clean build
java -jar ./build/libs/kotlin-mcp-server-0.1.0-all.jar --sse-server-ktor 3002

Use the MCP inspector to connect to http://localhost:3002/ via SSE transport (Click the "▶️ Connect" button):

npx @modelcontextprotocol/inspector --config mcp-inspector-config.json --server sse-ktor-server

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 (SSE modes)
  • Kotlin coroutines for asynchronous operations
  • SSE for real-time communication in web contexts
  • Standard I/O for command-line interface and process-based communication

Example Capabilities

The sample server demonstrates:

  • Prompt: "Kotlin Developer" - helps develop small Kotlin applications with a configurable project name
  • Tool: "kotlin-sdk-tool" - a simple test tool that returns a greeting
  • Resource: "Web Search" - a placeholder resource demonstrating resource handling