Refactor mcp server, rename connect to (#364)

- Rename `connect` to `createSession` in `Server.kt `to make naming more
clear
- Add block to configure build to `Server.kt`
- Move sse test to jvm to be able to run, small test refactoring
- Introduce base integration test for sse server / client

kotlin-sdk-server/api/kotlin-sdk-server.api

@@ -45,9 +45,10 @@ public final class io/modelcontextprotocol/kotlin/sdk/server/RegisteredTool {
 }
 
 public class io/modelcontextprotocol/kotlin/sdk/server/Server {
-	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Ljava/lang/String;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
-	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;Lkotlin/jvm/functions/Function1;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/Implementation;Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;Lkotlin/jvm/functions/Function0;Lkotlin/jvm/functions/Function1;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun addPrompt (Lio/modelcontextprotocol/kotlin/sdk/Prompt;Lkotlin/jvm/functions/Function2;)V
 	public final fun addPrompt (Ljava/lang/String;Ljava/lang/String;Ljava/util/List;Lkotlin/jvm/functions/Function2;)V
 	public static synthetic fun addPrompt$default (Lio/modelcontextprotocol/kotlin/sdk/server/Server;Ljava/lang/String;Ljava/lang/String;Ljava/util/List;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
@@ -61,6 +62,7 @@ public class io/modelcontextprotocol/kotlin/sdk/server/Server {
 	public final fun addTools (Ljava/util/List;)V
 	public final fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public final fun connect (Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public final fun createSession (Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	protected final fun getInstructionsProvider ()Lkotlin/jvm/functions/Function0;
 	protected final fun getOptions ()Lio/modelcontextprotocol/kotlin/sdk/server/ServerOptions;
 	public final fun getPrompts ()Ljava/util/Map;

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/KtorServer.kt

@@ -88,7 +88,7 @@ internal suspend fun ServerSSESession.mcpSseEndpoint(
         sseTransportManager.removeTransport(transport.sessionId)
     }
 
-    server.connect(transport)
+    server.createSession(transport)
 
     logger.debug { "Server connected to transport for sessionId: ${transport.sessionId}" }
 }

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/Server.kt

@@ -57,12 +57,14 @@ public class ServerOptions(public val capabilities: ServerCapabilities, enforceS
  * @param options Configuration options for the server.
  * @param instructionsProvider Optional provider for instructions from the server to the client about how to use
  * this server. The provider is called each time a new session is started to support dynamic instructions.
+ * @param block A block to configure the mcp server.
  */
 
 public open class Server(
     protected val serverInfo: Implementation,
     protected val options: ServerOptions,
     protected val instructionsProvider: (() -> String)? = null,
+    block: Server.() -> Unit = {},
 ) {
     /**
      * Alternative constructor that provides the instructions directly as a string.
@@ -70,12 +72,14 @@ public open class Server(
      * @param serverInfo Information about this server implementation (name, version).
      * @param options Configuration options for the server.
      * @param instructions Instructions from the server to the client about how to use this server.
+     * @param block A block to configure the mcp server.
      */
     public constructor(
         serverInfo: Implementation,
         options: ServerOptions,
         instructions: String,
-    ) : this(serverInfo, options, { instructions })
+        block: Server.() -> Unit = {},
+    ) : this(serverInfo, options, { instructions }, block)
 
     private val sessions = atomic(persistentListOf<ServerSession>())
 
@@ -98,6 +102,10 @@ public open class Server(
     public val resources: Map<String, RegisteredResource>
         get() = _resources.value
 
+    init {
+        block(this)
+    }
+
     public suspend fun close() {
         logger.debug { "Closing MCP server" }
         sessions.value.forEach { it.close() }
@@ -111,7 +119,21 @@ public open class Server(
      * @param transport The transport layer to connect the session with.
      * @return The initialized and connected server session.
      */
-    public suspend fun connect(transport: Transport): ServerSession {
+    @Deprecated(
+        "Use createSession(transport) instead.",
+        ReplaceWith("createSession(transport)"),
+        DeprecationLevel.WARNING,
+    )
+    public suspend fun connect(transport: Transport): ServerSession = createSession(transport)
+
+    /**
+     * Starts a new server session with the given transport and initializes
+     * internal request handlers based on the server's capabilities.
+     *
+     * @param transport The transport layer to connect the session with.
+     * @return The initialized and connected server session.
+     */
+    public suspend fun createSession(transport: Transport): ServerSession {
         val session = ServerSession(serverInfo, options, instructionsProvider?.invoke())
 
         // Internal handlers for tools

kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/WebSocketMcpKtorServerExtensions.kt

@@ -69,7 +69,7 @@ internal suspend fun WebSocketServerSession.mcpWebSocketEndpoint(block: () -> Se
     val server = block()
     var session: ServerSession? = null
     try {
-        session = server.connect(transport)
+        session = server.createSession(transport)
         awaitCancellation()
     } catch (e: CancellationException) {
         session?.close()
@@ -103,7 +103,7 @@ public fun Route.mcpWebSocket(options: ServerOptions? = null, handler: suspend S
 )
 public fun Route.mcpWebSocket(block: () -> Server) {
     webSocket {
-        block().connect(createMcpTransport(this))
+        block().createSession(createMcpTransport(this))
     }
 }
 
@@ -190,7 +190,7 @@ private suspend fun Route.createMcpServer(
         ),
     )
 
-    server.connect(transport)
+    server.createSession(transport)
     handler(server)
     server.close()
 }

kotlin-sdk-test/build.gradle.kts

@@ -24,7 +24,6 @@ kotlin {
         }
         jvmTest {
             dependencies {
-                implementation(kotlin("test-junit5"))
                 implementation(libs.awaitility)
                 runtimeOnly(libs.slf4j.simple)
             }

kotlin-sdk-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientTest.kt

@@ -258,7 +258,7 @@ class ClientTest {
                 client.connect(clientTransport)
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
             },
         ).joinAll()
 
@@ -322,7 +322,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                server.connect(serverTransport)
+                server.createSession(serverTransport)
                 println("Server connected")
             },
         ).joinAll()
@@ -379,7 +379,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -439,7 +439,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -502,7 +502,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -594,7 +594,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -680,7 +680,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -812,7 +812,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -859,7 +859,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()
@@ -939,7 +939,7 @@ class ClientTest {
                 println("Client connected")
             },
             launch {
-                serverSessionResult.complete(server.connect(serverTransport))
+                serverSessionResult.complete(server.createSession(serverTransport))
                 println("Server connected")
             },
         ).joinAll()

kotlin-sdk-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/SseTransportTest.kt

@@ -48,7 +48,7 @@ class SseTransportTest : BaseTransportTest() {
 
         val actualPort = server.actualPort()
 
-        val client = HttpClient {
+        val transport = HttpClient {
             install(ClientSSE)
         }.mcpSseTransport {
             url {
@@ -58,7 +58,7 @@ class SseTransportTest : BaseTransportTest() {
         }
 
         try {
-            testClientOpenClose(client)
+            testTransportRead(transport)
         } finally {
             server.stopSuspend()
         }
@@ -76,7 +76,7 @@ class SseTransportTest : BaseTransportTest() {
 
         val actualPort = server.actualPort()
 
-        val client = HttpClient {
+        val transport = HttpClient {
             install(ClientSSE)
         }.mcpSseTransport {
             url {
@@ -86,7 +86,7 @@ class SseTransportTest : BaseTransportTest() {
         }
 
         try {
-            testClientRead(client)
+            testTransportRead(transport)
         } finally {
             server.stopSuspend()
         }
@@ -104,7 +104,7 @@ class SseTransportTest : BaseTransportTest() {
 
         val actualPort = server.actualPort()
 
-        val client = HttpClient {
+        val transport = HttpClient {
             install(ClientSSE)
         }.mcpSseTransport {
             url {
@@ -115,7 +115,7 @@ class SseTransportTest : BaseTransportTest() {
         }
 
         try {
-            testClientRead(client)
+            testTransportRead(transport)
         } finally {
             server.stopSuspend()
         }

kotlin-sdk-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/WebSocketTransportTest.kt

@@ -22,7 +22,7 @@ class WebSocketTransportTest : BaseTransportTest() {
             install(io.ktor.client.plugins.websocket.WebSockets)
         }.mcpWebSocketTransport()
 
-        testClientOpenClose(client)
+        testTransportOpenClose(client)
     }
 
     @Test
@@ -41,11 +41,11 @@ class WebSocketTransportTest : BaseTransportTest() {
             }
         }
 
-        val client = createClient {
+        val transport = createClient {
             install(io.ktor.client.plugins.websocket.WebSockets)
         }.mcpWebSocketTransport()
 
-        testClientRead(client)
+        testTransportRead(transport)
 
         clientFinished.complete(Unit)
     }

kotlin-sdk-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/SseIntegrationTest.kt

@@ -1,199 +0,0 @@
-package io.modelcontextprotocol.kotlin.sdk.integration
-
-import io.ktor.client.HttpClient
-import io.ktor.client.plugins.sse.SSE
-import io.ktor.server.application.install
-import io.ktor.server.cio.CIOApplicationEngine
-import io.ktor.server.engine.EmbeddedServer
-import io.ktor.server.engine.embeddedServer
-import io.ktor.server.routing.routing
-import io.modelcontextprotocol.kotlin.sdk.GetPromptRequest
-import io.modelcontextprotocol.kotlin.sdk.GetPromptResult
-import io.modelcontextprotocol.kotlin.sdk.Implementation
-import io.modelcontextprotocol.kotlin.sdk.PromptArgument
-import io.modelcontextprotocol.kotlin.sdk.PromptMessage
-import io.modelcontextprotocol.kotlin.sdk.Role
-import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
-import io.modelcontextprotocol.kotlin.sdk.TextContent
-import io.modelcontextprotocol.kotlin.sdk.client.Client
-import io.modelcontextprotocol.kotlin.sdk.client.mcpSseTransport
-import io.modelcontextprotocol.kotlin.sdk.server.Server
-import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
-import io.modelcontextprotocol.kotlin.sdk.server.mcp
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.test.runTest
-import kotlinx.coroutines.withContext
-import kotlin.test.Ignore
-import kotlin.test.Test
-import kotlin.test.assertTrue
-import kotlin.time.Duration.Companion.seconds
-import io.ktor.client.engine.cio.CIO as ClientCIO
-import io.ktor.server.cio.CIO as ServerCIO
-import io.ktor.server.sse.SSE as ServerSSE
-
-class SseIntegrationTest {
-    @Test
-    @Ignore // Ignored because it doesn’t work with wasm/js in Ktor 3.2.3
-    fun `client should be able to connect to sse server`() = runTest(timeout = 5.seconds) {
-        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
-        var client: Client? = null
-
-        try {
-            withContext(Dispatchers.Default) {
-                server = initServer()
-                val port = server.engine.resolvedConnectors().first().port
-                client = initClient(serverPort = port)
-            }
-        } finally {
-            client?.close()
-            server?.stopSuspend(1000, 2000)
-        }
-    }
-
-    /**
-     * Test Case #1: One opened connection, a client gets a prompt
-     *
-     * 1. Open SSE from Client A.
-     * 2. Send a POST request from Client A to POST /prompts/get.
-     * 3. Observe that Client A receives a response related to it.
-     */
-    @Test
-    @Ignore // Ignored because it doesn’t work with wasm/js in Ktor 3.2.3
-    fun `single sse connection`() = runTest(timeout = 5.seconds) {
-        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
-        var client: Client? = null
-        try {
-            withContext(Dispatchers.Default) {
-                server = initServer()
-                val port = server.engine.resolvedConnectors().first().port
-                client = initClient("Client A", port)
-
-                val promptA = getPrompt(client, "Client A")
-                assertTrue { "Client A" in promptA }
-            }
-        } finally {
-            client?.close()
-            server?.stopSuspend(1000, 2000)
-        }
-    }
-
-    /**
-     * Test Case #1: Two open connections, each client gets a client-specific prompt
-     *
-     * 1. Open SSE connection #1 from Client A and note the sessionId=<sessionId#1> value.
-     * 2. Open SSE connection #2 from Client B and note the sessionId=<sessionId#2> value.
-     * 3. Send a POST request to POST /message with the corresponding sessionId#1.
-     * 4. Observe that Client B (connection #2) receives a response related to sessionId#1.
-     */
-    @Test
-    @Ignore // Ignored because it doesn’t work with wasm/js in Ktor 3.2.3
-    fun `multiple sse connections`() = runTest(timeout = 5.seconds) {
-        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
-        var clientA: Client? = null
-        var clientB: Client? = null
-
-        try {
-            withContext(Dispatchers.Default) {
-                server = initServer()
-                val port = server.engine.resolvedConnectors().first().port
-
-                clientA = initClient("Client A", port)
-                clientB = initClient("Client B", port)
-
-                // Step 3: Send a prompt request from Client A
-                val promptA = getPrompt(clientA, "Client A")
-                //  Step 4: Send a prompt request from Client B
-                val promptB = getPrompt(clientB, "Client B")
-
-                assertTrue { "Client A" in promptA }
-                assertTrue { "Client B" in promptB }
-            }
-        } finally {
-            clientA?.close()
-            clientB?.close()
-            server?.stopSuspend(1000, 2000)
-        }
-    }
-
-    private suspend fun initClient(name: String = "", serverPort: Int): Client {
-        val client = Client(
-            Implementation(name = name, version = "1.0.0"),
-        )
-
-        val httpClient = HttpClient(ClientCIO) {
-            install(SSE)
-        }
-
-        // Create a transport wrapper that captures the session ID and received messages
-        val transport = httpClient.mcpSseTransport {
-            url {
-                host = URL
-                port = serverPort
-            }
-        }
-
-        client.connect(transport)
-
-        return client
-    }
-
-    private suspend fun initServer(): EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration> {
-        val server = Server(
-            Implementation(name = "sse-server", version = "1.0.0"),
-            ServerOptions(
-                capabilities = ServerCapabilities(prompts = ServerCapabilities.Prompts(listChanged = true)),
-            ),
-        )
-
-        server.addPrompt(
-            name = "prompt",
-            description = "Prompt description",
-            arguments = listOf(
-                PromptArgument(
-                    name = "client",
-                    description = "Client name who requested a prompt",
-                    required = true,
-                ),
-            ),
-        ) { request ->
-            GetPromptResult(
-                "Prompt for ${request.name}",
-                messages = listOf(
-                    PromptMessage(
-                        role = Role.user,
-                        content = TextContent("Prompt for client ${request.arguments?.get("client")}"),
-                    ),
-                ),
-            )
-        }
-
-        val ktorServer = embeddedServer(ServerCIO, host = URL, port = PORT) {
-            install(ServerSSE)
-            routing {
-                mcp { server }
-            }
-        }
-
-        return ktorServer.startSuspend(wait = false)
-    }
-
-    /**
-     * Retrieves a prompt result using the provided client and client name.
-     */
-    private suspend fun getPrompt(client: Client, clientName: String): String {
-        val response = client.getPrompt(
-            GetPromptRequest(
-                "prompt",
-                arguments = mapOf("client" to clientName),
-            ),
-        )
-
-        return (response.messages.first().content as? TextContent)?.text
-            ?: error("Failed to receive prompt for Client $clientName")
-    }
-
-    companion object {
-        private const val URL = "127.0.0.1"
-        private const val PORT = 0
-    }
-}

kotlin-sdk-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/BaseTransportTest.kt

@@ -11,23 +11,24 @@ import kotlin.test.assertTrue
 import kotlin.test.fail
 
 abstract class BaseTransportTest {
-    protected suspend fun testClientOpenClose(client: Transport) {
+
-        client.onError { error ->
+    protected suspend fun testTransportOpenClose(transport: Transport) {
+        transport.onError { error ->
             fail("Unexpected error: $error")
         }
 
         var didClose = false
-        client.onClose { didClose = true }
+        transport.onClose { didClose = true }
 
-        client.start()
+        transport.start()
         assertFalse(didClose, "Transport should not be closed immediately after start")
 
-        client.close()
+        transport.close()
         assertTrue(didClose, "Transport should be closed after close() call")
     }
 
-    protected suspend fun testClientRead(client: Transport) {
+    protected suspend fun testTransportRead(transport: Transport) {
-        client.onError { error ->
+        transport.onError { error ->
             error.printStackTrace()
             fail("Unexpected error: $error")
         }
@@ -40,23 +41,23 @@ abstract class BaseTransportTest {
         val readMessages = mutableListOf<JSONRPCMessage>()
         val finished = CompletableDeferred<Unit>()
 
-        client.onMessage { message ->
+        transport.onMessage { message ->
             readMessages.add(message)
             if (message == messages.last()) {
                 finished.complete(Unit)
             }
         }
 
-        client.start()
+        transport.start()
 
         for (message in messages) {
-            client.send(message)
+            transport.send(message)
         }
 
         finished.await()
 
         assertEquals(messages, readMessages, "Assert messages received")
 
-        client.close()
+        transport.close()
     }
 }

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/StdioClientTransportTest.kt

@@ -22,7 +22,7 @@ class StdioClientTransportTest : BaseTransportTest() {
             output = output,
         )
 
-        testClientOpenClose(client)
+        testTransportOpenClose(client)
 
         process.destroy()
     }
@@ -40,7 +40,7 @@ class StdioClientTransportTest : BaseTransportTest() {
             output = output,
         )
 
-        testClientRead(client)
+        testTransportRead(client)
 
         process.waitFor()
         process.destroy()
@@ -60,7 +60,7 @@ class StdioClientTransportTest : BaseTransportTest() {
             output = output,
         )
 
-        testClientRead(client)
+        testTransportRead(client)
 
         process.waitFor()
         process.destroy()

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/kotlin/KotlinTestBase.kt

@@ -139,7 +139,7 @@ abstract class KotlinTestBase {
 
             // Start server transport by connecting the server
             runBlocking {
-                server.connect(serverTransport)
+                server.createSession(serverTransport)
             }
         }
     }

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/sse/AbstractSseIntegrationTest.kt

@@ -0,0 +1,105 @@
+package io.modelcontextprotocol.kotlin.sdk.integration.sse
+
+import io.ktor.client.HttpClient
+import io.ktor.client.plugins.sse.SSE
+import io.ktor.server.application.install
+import io.ktor.server.cio.CIOApplicationEngine
+import io.ktor.server.engine.EmbeddedServer
+import io.ktor.server.engine.embeddedServer
+import io.ktor.server.routing.routing
+import io.modelcontextprotocol.kotlin.sdk.GetPromptResult
+import io.modelcontextprotocol.kotlin.sdk.Implementation
+import io.modelcontextprotocol.kotlin.sdk.PromptArgument
+import io.modelcontextprotocol.kotlin.sdk.PromptMessage
+import io.modelcontextprotocol.kotlin.sdk.Role
+import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
+import io.modelcontextprotocol.kotlin.sdk.TextContent
+import io.modelcontextprotocol.kotlin.sdk.client.Client
+import io.modelcontextprotocol.kotlin.sdk.client.mcpSseTransport
+import io.modelcontextprotocol.kotlin.sdk.server.Server
+import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
+import io.modelcontextprotocol.kotlin.sdk.server.mcp
+import io.ktor.client.engine.cio.CIO as ClientCIO
+import io.ktor.server.cio.CIO as ServerCIO
+import io.ktor.server.sse.SSE as ServerSSE
+
+open class AbstractSseIntegrationTest {
+
+    suspend fun EmbeddedServer<*, *>.actualPort() = engine.resolvedConnectors().single().port
+
+    suspend fun initTestClient(serverPort: Int, name: String? = null): Client {
+        val client = Client(
+            Implementation(name = name ?: DEFAULT_CLIENT_NAME, version = VERSION),
+        )
+
+        val httpClient = HttpClient(ClientCIO) {
+            install(SSE)
+        }
+
+        // Create a transport wrapper that captures the session ID and received messages
+        val transport = httpClient.mcpSseTransport {
+            url {
+                host = URL
+                port = serverPort
+            }
+        }
+
+        client.connect(transport)
+
+        return client
+    }
+
+    suspend fun initTestServer(
+        name: String? = null,
+    ): EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration> {
+        val server = Server(
+            Implementation(name = name ?: DEFAULT_SERVER_NAME, version = VERSION),
+            ServerOptions(
+                capabilities = ServerCapabilities(prompts = ServerCapabilities.Prompts(listChanged = true)),
+            ),
+        ) {
+            addPrompt(
+                name = "prompt",
+                description = "Prompt description",
+                arguments = listOf(
+                    PromptArgument(
+                        name = "client",
+                        description = "Client name who requested a prompt",
+                        required = true,
+                    ),
+                ),
+            ) { request ->
+                GetPromptResult(
+                    "Prompt for ${request.name}",
+                    messages = listOf(
+                        PromptMessage(
+                            role = Role.user,
+                            content = TextContent("Prompt for client ${request.arguments?.get("client")}"),
+                        ),
+                    ),
+                )
+            }
+        }
+
+        val ktorServer = embeddedServer(
+            ServerCIO,
+            host = URL,
+            port = PORT,
+        ) {
+            install(ServerSSE)
+            routing {
+                mcp { server }
+            }
+        }
+
+        return ktorServer.startSuspend(wait = false)
+    }
+
+    companion object {
+        private const val DEFAULT_CLIENT_NAME = "sse-test-client"
+        private const val DEFAULT_SERVER_NAME = "sse-test-server"
+        private const val VERSION = "1.0.0"
+        private const val URL = "127.0.0.1"
+        private const val PORT = 0
+    }
+}

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/sse/SseIntegrationTest.kt

@@ -0,0 +1,111 @@
+package io.modelcontextprotocol.kotlin.sdk.integration.sse
+
+import io.ktor.server.cio.CIOApplicationEngine
+import io.ktor.server.engine.EmbeddedServer
+import io.modelcontextprotocol.kotlin.sdk.GetPromptRequest
+import io.modelcontextprotocol.kotlin.sdk.TextContent
+import io.modelcontextprotocol.kotlin.sdk.client.Client
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.withContext
+import kotlin.test.Test
+import kotlin.test.assertTrue
+import kotlin.time.Duration.Companion.seconds
+
+class SSeIntegrationTest : AbstractSseIntegrationTest() {
+
+    @Test
+    fun `client should be able to connect to sse server`() = runTest(timeout = 5.seconds) {
+        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
+        var client: Client? = null
+
+        try {
+            withContext(Dispatchers.Default) {
+                server = initTestServer()
+                val port = server.engine.resolvedConnectors().single().port
+                client = initTestClient(serverPort = port)
+            }
+        } finally {
+            client?.close()
+            server?.stopSuspend(1000, 2000)
+        }
+    }
+
+    /**
+     * Test Case #1: One opened connection, a client gets a prompt
+     *
+     * 1. Open SSE from Client A.
+     * 2. Send a POST request from Client A to POST /prompts/get.
+     * 3. Observe that Client A receives a response related to it.
+     */
+    @Test
+    fun `single sse connection`() = runTest(timeout = 5.seconds) {
+        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
+        var client: Client? = null
+        try {
+            withContext(Dispatchers.Default) {
+                server = initTestServer()
+                val port = server.engine.resolvedConnectors().single().port
+                client = initTestClient(port, "Client A")
+
+                val promptA = getPrompt(client, "Client A")
+                assertTrue { "Client A" in promptA }
+            }
+        } finally {
+            client?.close()
+            server?.stopSuspend(1000, 2000)
+        }
+    }
+
+    /**
+     * Test Case #1: Two open connections, each client gets a client-specific prompt
+     *
+     * 1. Open SSE connection #1 from Client A and note the sessionId=<sessionId#1> value.
+     * 2. Open SSE connection #2 from Client B and note the sessionId=<sessionId#2> value.
+     * 3. Send a POST request to POST /message with the corresponding sessionId#1.
+     * 4. Observe that Client B (connection #2) receives a response related to sessionId#1.
+     */
+    @Test
+    fun `multiple sse connections`() = runTest(timeout = 5.seconds) {
+        var server: EmbeddedServer<CIOApplicationEngine, CIOApplicationEngine.Configuration>? = null
+        var clientA: Client? = null
+        var clientB: Client? = null
+
+        try {
+            withContext(Dispatchers.Default) {
+                server = initTestServer()
+                val port = server.engine.resolvedConnectors().first().port
+
+                clientA = initTestClient(port, "Client A")
+                clientB = initTestClient(port, "Client B")
+
+                // Step 3: Send a prompt request from Client A
+                val promptA = getPrompt(clientA, "Client A")
+                //  Step 4: Send a prompt request from Client B
+                val promptB = getPrompt(clientB, "Client B")
+
+                assertTrue { "Client A" in promptA }
+                assertTrue { "Client B" in promptB }
+            }
+        } finally {
+            clientA?.close()
+            clientB?.close()
+            server?.stopSuspend(1000, 2000)
+        }
+    }
+
+    /**
+     * Retrieves a prompt result using the provided client and client name.
+     */
+    private suspend fun getPrompt(client: Client, clientName: String): String {
+        val response = client.getPrompt(
+            GetPromptRequest(
+                "prompt",
+                arguments = mapOf("client" to clientName),
+            ),
+        )
+
+        return (response.messages.first().content as? TextContent)?.text
+            ?: error("Failed to receive prompt for Client $clientName")
+    }
+}

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/TsTestBase.kt

@@ -412,7 +412,7 @@ abstract class TsTestBase {
         // Connect server in a background thread to avoid blocking
         val serverThread = Thread {
             try {
-                kotlinx.coroutines.runBlocking { server.connect(transport) }
+                kotlinx.coroutines.runBlocking { server.createSession(transport) }
             } catch (e: Exception) {
                 println("[STDIO-SERVER] Error connecting: ${e.message}")
             }

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/sse/KotlinServerForTsClientSse.kt

@@ -53,7 +53,6 @@ import kotlinx.serialization.json.buildJsonObject
 import kotlinx.serialization.json.contentOrNull
 import kotlinx.serialization.json.decodeFromJsonElement
 import kotlinx.serialization.json.jsonPrimitive
-import org.awaitility.Awaitility.await
 import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
 
@@ -134,7 +133,7 @@ class KotlinServerForTsClient {
 
                             val serverThread = Thread {
                                 runBlocking {
-                                    mcpServer.connect(transport)
+                                    mcpServer.createSession(transport)
                                 }
                             }
                             serverThread.start()

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ServerTest.kt

@@ -53,7 +53,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the tool
         val result = server.removeTool("test-tool")
@@ -90,7 +90,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Try to remove a non-existent tool
         val result = server.removeTool("non-existent-tool")
@@ -147,7 +147,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the tools
         val result = server.removeTools(listOf("test-tool-1", "test-tool-2"))
@@ -186,7 +186,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the prompt
         val result = server.removePrompt(testPrompt.name)
@@ -232,7 +232,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the prompts
         val result = server.removePrompts(listOf(testPrompt1.name, testPrompt2.name))
@@ -281,7 +281,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the resource
         val result = server.removeResource(testResourceUri)
@@ -347,7 +347,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Remove the resources
         val result = server.removeResources(listOf(testResourceUri1, testResourceUri2))
@@ -384,7 +384,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Try to remove a non-existent prompt
         val result = server.removePrompt("non-existent-prompt")
@@ -442,7 +442,7 @@ class ServerTest {
 
         // Connect client and server
         launch { client.connect(clientTransport) }
-        launch { server.connect(serverTransport) }
+        launch { server.createSession(serverTransport) }
 
         // Try to remove a non-existent resource
         val result = server.removeResource("non-existent-resource")
@@ -486,7 +486,7 @@ class ServerTest {
         val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
         val client = Client(clientInfo = Implementation(name = "test client", version = "1.0"))
 
-        server.connect(serverTransport)
+        server.createSession(serverTransport)
         client.connect(clientTransport)
 
         assertEquals(instructions, client.serverInstructions)
@@ -505,7 +505,7 @@ class ServerTest {
         val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
         val client = Client(clientInfo = Implementation(name = "test client", version = "1.0"))
 
-        server.connect(serverTransport)
+        server.createSession(serverTransport)
         client.connect(clientTransport)
 
         assertEquals(instructions, client.serverInstructions)
@@ -522,7 +522,7 @@ class ServerTest {
         val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
         val client = Client(clientInfo = Implementation(name = "test client", version = "1.0"))
 
-        server.connect(serverTransport)
+        server.createSession(serverTransport)
         client.connect(clientTransport)
 
         assertNull(client.serverInstructions)