add ios and wasm targets (modelcontextprotocol#81)

* add wasm and ios targets

* add yarn.lock file to gitignore

* clean up code

* fix typo in method name

* add wasm server example

* update jrelease publishing for klibs

* update gradle-publish workflow to use macos runner

* update README to reflect multiplatform support and clarify server setup for JVM and WASM

* remove the old main file from the kotlin-mcp-server example

* update api dump

* Refactor `build.gradle.kts`

* clean up imports and remove unnecessary charset specification in tests

* add JS target configuration and update API dump

Author: devcrocod

.github/workflows/gradle-publish.yml

@@ -13,7 +13,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: macos-latest
     environment: release
 
     permissions:

.github/workflows/validate-pr.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   validate-pr:
-    runs-on: ubuntu-latest
+    runs-on: macos-latest
     name: Validate PR
     steps:
       - uses: actions/checkout@v4

.gitignore

@@ -20,6 +20,7 @@ out/
 
 ### Kotlin ###
 .kotlin
+yarn.lock
 
 ### Eclipse ###
 .apt_generated

README.md

@@ -1,10 +1,19 @@
 # MCP Kotlin SDK
 
-Kotlin implementation of the [Model Context Protocol](https://modelcontextprotocol.io) (MCP), providing both client and server capabilities for integrating with LLM surfaces.
+[![Kotlin Multiplatform](https://img.shields.io/badge/Kotlin-Multiplatform-blueviolet?logo=kotlin)](https://kotlinlang.org/docs/multiplatform.html)
+[![Platforms](https://img.shields.io/badge/Platforms-JVM%20%7C%20Wasm%2FJS%20%7C%20Native%20(iOS%2FiOS%20Simulator)-blue)](https://kotlinlang.org/docs/multiplatform.html)
+[![Maven Central](https://img.shields.io/maven-central/v/io.modelcontextprotocol/kotlin-sdk.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:io.modelcontextprotocol%20a:kotlin-sdk)
+[![License](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)
+
+Kotlin Multiplatform implementation of the [Model Context Protocol](https://modelcontextprotocol.io) (MCP),
+providing both client and server capabilities for integrating with LLM surfaces across various platforms.
 
 ## Overview
 
-The Model Context Protocol allows applications to provide context for LLMs in a standardized way, separating the concerns of providing context from the actual LLM interaction. This Kotlin SDK implements the full MCP specification, making it easy to:
+The Model Context Protocol allows applications to provide context for LLMs in a standardized way,
+separating the concerns of providing context from the actual LLM interaction.
+This SDK implements the MCP specification for Kotlin,
+enabling you to build applications that can communicate using MCP on the JVM, WebAssembly and iOS.
 
 - Build MCP clients that can connect to any MCP server
 - Create MCP servers that expose resources, prompts and tools
@@ -13,7 +22,7 @@ The Model Context Protocol allows applications to provide context for LLMs in a
 
 ## Samples
 
-- [kotlin-mcp-server](./samples/kotlin-mcp-server): shows how to set up a Kotlin MCP server with different tools and other features.
+- [kotlin-mcp-server](./samples/kotlin-mcp-server): demonstrates a multiplatform (JVM, Wasm) MCP server setup with various features and transports.
 - [weather-stdio-server](./samples/weather-stdio-server): shows how to build a Kotlin MCP server providing weather forecast and alerts using STDIO transport.
 - [kotlin-mcp-client](./samples/kotlin-mcp-client): demonstrates building an interactive Kotlin MCP client that connects to an MCP server via STDIO and integrates with Anthropic’s API.
 
@@ -31,7 +40,8 @@ Add the dependency:
 
 ```kotlin
 dependencies {
-    implementation("io.modelcontextprotocol:kotlin-sdk:0.5.0")
+    // Use the badge above for the latest version
+    implementation("io.modelcontextprotocol:kotlin-sdk:$mcpVersion")
 }
 ```
 

api/kotlin-sdk.api

@@ -1,9 +1,14 @@
-@file:OptIn(ExperimentalKotlinGradlePluginApi::class)
+@file:OptIn(ExperimentalKotlinGradlePluginApi::class, ExperimentalWasmDsl::class)
 
 import org.jetbrains.dokka.gradle.engine.parameters.VisibilityModifier
 import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.ExplicitApiMode
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinMetadataTarget
+import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
 import org.jreleaser.model.Active
 
 plugins {
@@ -27,9 +32,11 @@ publishing {
     val javadocJar = configureEmptyJavadocArtifact()
 
     publications.withType(MavenPublication::class).all {
+        if (name.contains("jvm", ignoreCase = true)) {
+            artifact(javadocJar)
+        }
         pom.configureMavenCentralMetadata()
         signPublicationIfKeyPresent()
-        artifact(javadocJar)
     }
 
     repositories {
@@ -53,10 +60,28 @@ jreleaser {
             active.set(Active.ALWAYS)
             mavenCentral {
                 val ossrh by creating {
-                    applyMavenCentralRules = true
                     active.set(Active.ALWAYS)
                     url.set("https://central.sonatype.com/api/v1/publisher")
+                    applyMavenCentralRules = false
+                    maxRetries = 240
                     stagingRepository(layout.buildDirectory.dir("staging-deploy").get().asFile.path)
+                    // workaround: https://github.com/jreleaser/jreleaser/issues/1784
+                    kotlin.targets.forEach { target ->
+                        if (target !is KotlinJvmTarget && target !is KotlinAndroidTarget && target !is KotlinMetadataTarget) {
+                            val klibArtifactId = if (target.platformType == KotlinPlatformType.wasm) {
+                                "${name}-wasm-${target.name.lowercase().substringAfter("wasm")}"
+                            } else {
+                                "${name}-${target.name.lowercase()}"
+                            }
+                            artifactOverride {
+                                artifactId = klibArtifactId
+                                jar = false
+                                verifyPom = false
+                                sourceJar = false
+                                javadocJar = false
+                            }
+                        }
+                    }
                 }
             }
         }
@@ -194,6 +219,24 @@ kotlin {
         }
     }
 
+    iosArm64()
+    iosX64()
+    iosSimulatorArm64()
+
+    js(IR) {
+        nodejs {
+            testTask {
+                useMocha {
+                    timeout = "30s"
+                }
+            }
+        }
+    }
+
+    wasmJs {
+        nodejs()
+    }
+
     explicitApi = ExplicitApiMode.Strict
 
     jvmToolchain(21)
@@ -217,7 +260,6 @@ kotlin {
                 implementation(libs.kotlin.test)
                 implementation(libs.ktor.server.test.host)
                 implementation(libs.kotlinx.coroutines.test)
-                implementation(libs.kotlinx.coroutines.debug)
                 implementation(libs.kotest.assertions.json)
             }
         }

build.gradle.kts

@@ -5,3 +5,5 @@ org.gradle.configuration-cache.parallel=true
 
 org.jetbrains.dokka.experimental.gradle.pluginMode=V2Enabled
 org.jetbrains.dokka.experimental.gradle.pluginMode.noWarn=true
+
+kotlin.daemon.jvmargs=-Xmx2G

gradle.properties

@@ -5,8 +5,8 @@ dokka = "2.0.0"
 
 # libraries version
 serialization = "1.7.3"
-coroutines = "1.9.0"
-ktor = "3.0.2"
+coroutines = "1.10.2"
+ktor = "3.1.2"
 mockk = "1.13.13"
 logging = "7.0.0"
 jreleaser = "1.17.0"
@@ -28,7 +28,6 @@ ktor-server-cio = { group = "io.ktor", name = "ktor-server-cio", version.ref = "
 # Testing
 kotlin-test = { module = "org.jetbrains.kotlin:kotlin-test", version.ref = "kotlin" }
 kotlinx-coroutines-test = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-test", version.ref = "coroutines" }
-kotlinx-coroutines-debug = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-debug", version.ref = "coroutines" }
 ktor-server-test-host = { group = "io.ktor", name = "ktor-server-test-host", version.ref = "ktor" }
 mockk = { group = "io.mockk", name = "mockk", version.ref = "mockk" }
 slf4j-simple = { group = "org.slf4j", name = "slf4j-simple", version.ref = "slf4j" }

gradle/libs.versions.toml

@@ -1,13 +1,15 @@
 # MCP Kotlin Server Sample
 
-A sample implementation of an MCP (Model Communication Protocol) server in Kotlin that demonstrates different server configurations and transport methods.
+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
-    - SSE (Server-Sent Events) server with plain configuration
-    - SSE server using Ktor plugin
+    - 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
@@ -17,17 +19,30 @@ A sample implementation of an MCP (Model Communication Protocol) server in Kotli
 
 ### Running the Server
 
-To run the server in SSE mode on the port 3001, run:
+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):
+
+```bash
+./gradlew runJvm
+```
+
+#### WASM:
+
+To run the server using Kotlin/WASM on Node.js (defaults to SSE mode with Ktor plugin on port 3001):
 
 ```bash
-./gradlew run
+./gradlew wasmJsNodeDevelopmentRun
 ```
 
 ### Connecting to the Server
 
-For SSE servers (both plain and Ktor plugin versions):
+For servers on JVM or WASM:
 1. Start the server
-2. Use the MCP inspector to connect to `http://localhost:<port>/sse`
+2. Use the [MCP inspector](https://modelcontextprotocol.io/docs/tools/inspector) to connect to `http://localhost:<port>/sse`
 
 ## Server Capabilities
 
@@ -42,3 +57,4 @@ The server is implemented using:
 - 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

samples/kotlin-mcp-server/README.md

@@ -1,35 +1,53 @@
-plugins {
-    kotlin("jvm") version "2.1.0"
-    kotlin("plugin.serialization") version "2.1.0"
-    application
-}
+@file:OptIn(ExperimentalWasmDsl::class, ExperimentalKotlinGradlePluginApi::class)
 
-application {
-    mainClass.set("MainKt")
-}
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 
+plugins {
+    kotlin("multiplatform") version "2.1.20"
+    kotlin("plugin.serialization") version "2.1.20"
+}
 
 group = "org.example"
 version = "0.1.0"
 
-dependencies {
-    implementation("io.modelcontextprotocol:kotlin-sdk:0.5.0")
-    implementation("org.slf4j:slf4j-nop:2.0.9")
+repositories {
+    mavenCentral()
 }
 
-tasks.test {
-    useJUnitPlatform()
-}
-kotlin {
-    jvmToolchain(21)
-}
+val jvmMainClass = "Main_jvmKt"
 
-tasks.jar {
-    manifest {
-        attributes["Main-Class"] = "MainKt"
+kotlin {
+    jvmToolchain(17)
+    jvm {
+        binaries {
+            executable {
+                mainClass.set(jvmMainClass)
+            }
+        }
+        val jvmJar by tasks.getting(org.gradle.jvm.tasks.Jar::class) {
+            duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+            doFirst {
+                manifest {
+                    attributes["Main-Class"] = jvmMainClass
+                }
+
+                from(configurations["jvmRuntimeClasspath"].map { if (it.isDirectory) it else zipTree(it) })
+            }
+        }
+    }
+    wasmJs {
+        nodejs()
+        binaries.executable()
     }
 
-    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-
-    from(configurations.runtimeClasspath.get().map { if (it.isDirectory) it else zipTree(it) })
+    sourceSets {
+        commonMain.dependencies {
+            implementation("io.modelcontextprotocol:kotlin-sdk:0.5.0")
+        }
+        jvmMain.dependencies {
+            implementation("org.slf4j:slf4j-nop:2.0.9")
+        }
+        wasmJsMain.dependencies {}
+    }
 }