Official MCP Kotlin SDK

Overview

The official MCP Kotlin SDK is the Model Context Protocol project's Kotlin Multiplatform implementation for building MCP clients and servers. It is maintained under the modelcontextprotocol organization in collaboration with JetBrains and publishes Gradle/Maven artifacts under io.modelcontextprotocol.

The SDK targets JVM, Native, JS, and Wasm, which makes it useful for teams that want one Kotlin codebase to cover local tools, backend services, desktop-adjacent clients, and multiplatform agent infrastructure.

Gradle Dependency

For the umbrella SDK artifact:

dependencies {
    implementation("io.modelcontextprotocol:kotlin-sdk:0.13.0")
}

For smaller dependency surfaces, upstream also documents:

dependencies {
    implementation("io.modelcontextprotocol:kotlin-sdk-client:0.13.0")
    implementation("io.modelcontextprotocol:kotlin-sdk-server:0.13.0")
}

MCP Fit

Choose the official Kotlin SDK when you need MCP support in Kotlin Multiplatform, JVM, Ktor, or JetBrains-oriented environments. It is a strong fit for Kotlin service teams, multiplatform tool builders, Android-adjacent experiments, and JVM teams that prefer coroutine-first APIs.

Because the SDK supports multiple runtime targets and transports, production review should happen per target. A safe JVM server configuration does not prove the same behavior on Native, JS, or Wasm.

Core Capabilities

Use Cases

• Add an MCP server to a Kotlin or JVM service.
• Build a Kotlin MCP client for agent tooling or internal automation.
• Share MCP protocol code across JVM, Native, JS, and Wasm targets.
• Wire Streamable HTTP or SSE support through Ktor.
• Use client-only or server-only artifacts to reduce dependency scope.
• Test MCP behavior with ChannelTransport before exposing a real transport.

Source Review

Verified on 2026-06-18:

• The upstream repository description identifies it as the official Kotlin SDK for Model Context Protocol clients and servers, maintained in collaboration with JetBrains.
• The README describes a Kotlin Multiplatform SDK for MCP targeting JVM, Native, JS, and Wasm.
• The README documents artifacts for umbrella, client-only, and server-only SDK usage.
• The README covers stdio, SSE, Streamable HTTP, WebSocket, ChannelTransport, tools, resources, prompts, completion, logging, pagination, roots, and sampling.
• gradle.properties declares group io.modelcontextprotocol and version 0.13.0.
• The license file documents the MCP project's license transition terms for Apache-2.0, MIT, and CC-BY-4.0 documentation contributions.

Safety and Privacy

Kotlin MCP applications often bridge JVM services, Ktor servers, local tools, and multiplatform clients. Keep tool schemas narrow, validate all inputs, check user authorization, and avoid exposing private data through resources or error paths.

Review each target and transport separately. Ktor engine choices, browser-like targets, Native builds, WebSocket/SSE behavior, and logging pipelines can all change the practical privacy boundary.

Duplicate Check

Checked current content/mcp/, content/tools/, content/skills/, open pull requests, and repository-wide content for modelcontextprotocol/kotlin-sdk, official MCP Kotlin SDK, Model Context Protocol Kotlin SDK, Kotlin Multiplatform MCP, Kotlin MCP server SDK, Kotlin MCP client SDK, JetBrains MCP Kotlin, io.modelcontextprotocol:kotlin-sdk, and Ktor MCP server. Existing JetBrains content covers the JetBrains IDE MCP server, not this SDK. No dedicated official Kotlin SDK entry, exact source URL duplicate, target file, or open duplicate PR was found.