feat!: capabilities for tasks, elicitation (#732)

closes #544 

Replaces opaque `JsonObject?` modelling of `elicitation` with a typed
`ClientCapabilities.Elicitation` (`form`, `url`), and adds the new
`tasks` capability on both `ClientCapabilities` and `ServerCapabilities`
(with `list`, `cancel`, per-request-type augmentation). Wires capability
assertions for `tasks/*` methods and `notifications/tasks/status` into
`Client` and `ServerSession`

## How Has This Been Tested?
unit tests 

## Breaking Changes
yes
now elicitation is a specific class in capabilities 

## Types of changes
- [ ] 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

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

@@ -1058,7 +1058,7 @@ class ClientTest {
             Implementation(name = "test client", version = "1.0"),
             ClientOptions(
                 capabilities = ClientCapabilities(
-                    elicitation = EmptyJsonObject,
+                    elicitation = ClientCapabilities.Elicitation(),
                 ),
             ),
         )
@@ -1270,7 +1270,7 @@ class ClientTest {
     ): Pair<Client, ServerSession> = kotlinx.coroutines.coroutineScope {
         val client = Client(
             Implementation(name = "test client", version = "1.0"),
-            ClientOptions(capabilities = ClientCapabilities(elicitation = EmptyJsonObject)),
+            ClientOptions(capabilities = ClientCapabilities(elicitation = ClientCapabilities.Elicitation())),
         )
         client.setElicitationHandler(handler)
 

kotlin-sdk-client/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/client/Client.kt

@@ -174,6 +174,7 @@ public open class Client(private val clientInfo: Implementation, options: Client
             "prompts" -> caps?.prompts != null
             "resources" -> caps?.resources != null
             "tools" -> caps?.tools != null
+            "tasks" -> caps?.tasks != null
             else -> true
         }
 
@@ -267,6 +268,12 @@ public open class Client(private val clientInfo: Implementation, options: Client
                 }
             }
 
+            Method.Defined.TasksGet,
+            Method.Defined.TasksResult,
+            Method.Defined.TasksList,
+            Method.Defined.TasksCancel,
+            -> assertTasksCapabilityForMethod(method)
+
             Method.Defined.Initialize, Method.Defined.Ping -> {
                 // No specific capability required
             }
@@ -277,6 +284,24 @@ public open class Client(private val clientInfo: Implementation, options: Client
         }
     }
 
+    private fun assertTasksCapabilityForMethod(method: Method) {
+        val tasks = serverCapabilities?.tasks
+            ?: error("Server does not support tasks (required for $method)")
+        when (method) {
+            Method.Defined.TasksList -> checkNotNull(tasks.list) {
+                "Server does not support listing tasks (required for $method)"
+            }
+
+            Method.Defined.TasksCancel -> checkNotNull(tasks.cancel) {
+                "Server does not support cancelling tasks (required for $method)"
+            }
+
+            else -> {
+                // TasksGet, TasksResult: base tasks capability suffices.
+            }
+        }
+    }
+
     override fun assertNotificationCapability(method: Method) {
         when (method) {
             Method.Defined.NotificationsRootsListChanged -> {
@@ -285,6 +310,12 @@ public open class Client(private val clientInfo: Implementation, options: Client
                 }
             }
 
+            Method.Defined.NotificationsTasksStatus -> {
+                checkNotNull(capabilities.tasks) {
+                    "Client does not support tasks (required for $method)"
+                }
+            }
+
             Method.Defined.NotificationsInitialized,
             Method.Defined.NotificationsCancelled,
             Method.Defined.NotificationsProgress,

kotlin-sdk-client/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientAssertCapabilityTest.kt

@@ -0,0 +1,152 @@
+package io.modelcontextprotocol.kotlin.sdk.client
+
+import io.kotest.matchers.string.shouldContain
+import io.modelcontextprotocol.kotlin.sdk.shared.Transport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
+import io.modelcontextprotocol.kotlin.sdk.types.ClientCapabilities
+import io.modelcontextprotocol.kotlin.sdk.types.Implementation
+import io.modelcontextprotocol.kotlin.sdk.types.InitializeResult
+import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
+import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCRequest
+import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCResponse
+import io.modelcontextprotocol.kotlin.sdk.types.LATEST_PROTOCOL_VERSION
+import io.modelcontextprotocol.kotlin.sdk.types.Method
+import io.modelcontextprotocol.kotlin.sdk.types.ServerCapabilities
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertFailsWith
+
+/**
+ * Tests for the protected helper [Client.assertCapability].
+ *
+ * `assertCapability(capability, method)` is `protected`, so this suite uses
+ * a small subclass [TestClient] that re-exports it via [TestClient.exposedAssertCapability].
+ * Server capabilities are seeded by completing the initialization handshake through
+ * [CapabilitiesTransport], which replays a configurable [ServerCapabilities] in its
+ * `initialize` response.
+ */
+class ClientAssertCapabilityTest {
+
+    @Test
+    fun `assertCapability tasks throws when server has no tasks capability`() = runTest {
+        val client = newTestClient(serverCapabilities = ServerCapabilities())
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertCapability("tasks", "tasks/list")
+        }
+        ex.message.orEmpty() shouldContain "Server does not support tasks"
+    }
+
+    @Test
+    fun `TasksGet throws when server has no tasks capability`() = runTest {
+        val client = newTestClient(serverCapabilities = ServerCapabilities())
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertCapabilityForMethod(Method.Defined.TasksGet)
+        }
+        ex.message.orEmpty() shouldContain "Server does not support tasks"
+    }
+
+    @Test
+    fun `TasksGet does not throw when server declared tasks`() = runTest {
+        val client = newTestClient(
+            serverCapabilities = ServerCapabilities(tasks = ServerCapabilities.Tasks()),
+        )
+        client.exposedAssertCapabilityForMethod(Method.Defined.TasksGet)
+    }
+
+    @Test
+    fun `TasksList throws when server tasks list is null`() = runTest {
+        val client = newTestClient(
+            serverCapabilities = ServerCapabilities(tasks = ServerCapabilities.Tasks()),
+        )
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertCapabilityForMethod(Method.Defined.TasksList)
+        }
+        ex.message.orEmpty() shouldContain "Server does not support listing tasks"
+    }
+
+    @Test
+    fun `TasksCancel throws when server tasks cancel is null`() = runTest {
+        val client = newTestClient(
+            serverCapabilities = ServerCapabilities(tasks = ServerCapabilities.Tasks()),
+        )
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertCapabilityForMethod(Method.Defined.TasksCancel)
+        }
+        ex.message.orEmpty() shouldContain "Server does not support cancelling tasks"
+    }
+
+    @Test
+    fun `NotificationsTasksStatus throws when client has no tasks capability`() = runTest {
+        val client = newTestClient(clientCapabilities = ClientCapabilities())
+        val ex = assertFailsWith<IllegalStateException> {
+            client.exposedAssertNotificationCapability(Method.Defined.NotificationsTasksStatus)
+        }
+        ex.message.orEmpty() shouldContain "Client does not support tasks"
+    }
+
+    private suspend fun newTestClient(
+        serverCapabilities: ServerCapabilities = ServerCapabilities(),
+        clientCapabilities: ClientCapabilities = ClientCapabilities(),
+    ): TestClient {
+        val client = TestClient(
+            Implementation("test-client", "1.0.0"),
+            ClientOptions(capabilities = clientCapabilities),
+        )
+        val transport = CapabilitiesTransport(serverCapabilities)
+        client.connect(transport)
+        return client
+    }
+
+    /**
+     * Test-only [Client] subclass that exposes the protected
+     * [Client.assertCapability], [Client.assertCapabilityForMethod], and
+     * [Client.assertNotificationCapability] helpers to the test code.
+     */
+    private class TestClient(clientInfo: Implementation, options: ClientOptions = ClientOptions()) :
+        Client(clientInfo, options) {
+        fun exposedAssertCapability(capability: String, method: String): Unit = assertCapability(capability, method)
+        fun exposedAssertCapabilityForMethod(method: Method): Unit = assertCapabilityForMethod(method)
+        fun exposedAssertNotificationCapability(method: Method): Unit = assertNotificationCapability(method)
+    }
+
+    /**
+     * Minimal in-memory [Transport] that responds to `initialize` with a configurable
+     * [ServerCapabilities]. Other JSON-RPC traffic (e.g. the `notifications/initialized`
+     * sent by [Client.connect]) is silently consumed.
+     */
+    private class CapabilitiesTransport(private val serverCapabilities: ServerCapabilities) : Transport {
+        private var onMessageBlock: (suspend (JSONRPCMessage) -> Unit)? = null
+        private var onCloseBlock: (() -> Unit)? = null
+
+        override suspend fun start() = Unit
+
+        override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
+            if (message is JSONRPCRequest && message.method == "initialize") {
+                onMessageBlock?.invoke(
+                    JSONRPCResponse(
+                        id = message.id,
+                        result = InitializeResult(
+                            protocolVersion = LATEST_PROTOCOL_VERSION,
+                            capabilities = serverCapabilities,
+                            serverInfo = Implementation("mock-server", "1.0.0"),
+                        ),
+                    ),
+                )
+            }
+        }
+
+        override suspend fun close() {
+            onCloseBlock?.invoke()
+        }
+
+        override fun onMessage(block: suspend (JSONRPCMessage) -> Unit) {
+            onMessageBlock = block
+        }
+
+        override fun onClose(block: () -> Unit) {
+            onCloseBlock = block
+        }
+
+        override fun onError(block: (Throwable) -> Unit) = Unit
+    }
+}

kotlin-sdk-core/api/kotlin-sdk-core.api

@@ -607,23 +607,25 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/CancelledNotificatio
 public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities {
 	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Companion;
 	public fun <init> ()V
-	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)V
-	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun <init> (Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)V
 	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;
 	public final fun component2 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;
-	public final fun component3 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component3 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
-	public final fun component4 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component4 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;
-	public final fun component5 ()Ljava/util/Map;
+	public final fun component5 ()Lkotlinx/serialization/json/JsonObject;
-	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;
+	public final fun component6 ()Ljava/util/Map;
-	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;
+	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;
 	public fun equals (Ljava/lang/Object;)Z
-	public final fun getElicitation ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getElicitation ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
 	public final fun getExperimental ()Lkotlinx/serialization/json/JsonObject;
 	public final fun getExtensions ()Ljava/util/Map;
 	public final fun getRoots ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots;
 	public final fun getSampling ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;
+	public final fun getTasks ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
 }
@@ -640,11 +642,42 @@ public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapa
 }
 
 public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Companion {
-	public final fun getElicitation ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getElicitation ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
 	public final fun getSampling ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Sampling;
 	public final fun serializer ()Lkotlinx/serialization/KSerializer;
 }
 
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component2 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getForm ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getUrl ()Lkotlinx/serialization/json/JsonObject;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
 public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots {
 	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Roots$Companion;
 	public fun <init> ()V
@@ -705,11 +738,132 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$S
 	public final fun serializer ()Lkotlinx/serialization/KSerializer;
 }
 
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component2 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component3 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getCancel ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getList ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getRequests ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Companion;
+	public fun <init> ()V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;
+	public final fun component2 ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;
+	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getElicitation ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;
+	public final fun getSampling ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;Lkotlinx/serialization/json/JsonObject;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getCreate ()Lkotlinx/serialization/json/JsonObject;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Elicitation$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;Lkotlinx/serialization/json/JsonObject;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getCreateMessage ()Lkotlinx/serialization/json/JsonObject;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Tasks$Requests$Sampling$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
 public final class io/modelcontextprotocol/kotlin/sdk/types/ClientCapabilitiesBuilder {
 	public fun <init> ()V
 	public final fun build ()Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities;
-	public final fun elicitation (Lkotlin/jvm/functions/Function1;)V
+	public final fun elicitation (Lio/modelcontextprotocol/kotlin/sdk/types/ClientCapabilities$Elicitation;)V
-	public final fun elicitation (Lkotlinx/serialization/json/JsonObject;)V
 	public final fun experimental (Lkotlin/jvm/functions/Function1;)V
 	public final fun experimental (Lkotlinx/serialization/json/JsonObject;)V
 	public final fun extensions (Ljava/util/Map;)V
@@ -4303,17 +4457,18 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/Sampling_dslKt {
 public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities {
 	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Companion;
 	public fun <init> ()V
-	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)V
-	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;
 	public final fun component2 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;
 	public final fun component3 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;
 	public final fun component4 ()Lkotlinx/serialization/json/JsonObject;
 	public final fun component5 ()Lkotlinx/serialization/json/JsonObject;
-	public final fun component6 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component6 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;
-	public final fun component7 ()Ljava/util/Map;
+	public final fun component7 ()Lkotlinx/serialization/json/JsonObject;
-	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;
+	public final fun component8 ()Ljava/util/Map;
-	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;
+	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Ljava/util/Map;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getCompletions ()Lkotlinx/serialization/json/JsonObject;
 	public final fun getExperimental ()Lkotlinx/serialization/json/JsonObject;
@@ -4321,6 +4476,7 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities {
 	public final fun getLogging ()Lkotlinx/serialization/json/JsonObject;
 	public final fun getPrompts ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Prompts;
 	public final fun getResources ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Resources;
+	public final fun getTasks ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;
 	public final fun getTools ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools;
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
@@ -4403,6 +4559,97 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$R
 	public final fun serializer ()Lkotlinx/serialization/KSerializer;
 }
 
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component2 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun component3 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;Lkotlinx/serialization/json/JsonObject;Lkotlinx/serialization/json/JsonObject;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getCancel ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getList ()Lkotlinx/serialization/json/JsonObject;
+	public final fun getRequests ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Companion;
+	public fun <init> ()V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;
+	public final fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getTools ()Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools {
+	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools$Companion;
+	public fun <init> ()V
+	public fun <init> (Lkotlinx/serialization/json/JsonObject;)V
+	public synthetic fun <init> (Lkotlinx/serialization/json/JsonObject;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lkotlinx/serialization/json/JsonObject;
+	public final fun copy (Lkotlinx/serialization/json/JsonObject;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;Lkotlinx/serialization/json/JsonObject;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getCall ()Lkotlinx/serialization/json/JsonObject;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
+public final synthetic class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools$$serializer : kotlinx/serialization/internal/GeneratedSerializer {
+	public static final field INSTANCE Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools$$serializer;
+	public final fun childSerializers ()[Lkotlinx/serialization/KSerializer;
+	public final fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;
+	public synthetic fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Ljava/lang/Object;
+	public final fun getDescriptor ()Lkotlinx/serialization/descriptors/SerialDescriptor;
+	public final fun serialize (Lkotlinx/serialization/encoding/Encoder;Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools;)V
+	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
+	public fun typeParametersSerializers ()[Lkotlinx/serialization/KSerializer;
+}
+
+public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tasks$Requests$Tools$Companion {
+	public final fun serializer ()Lkotlinx/serialization/KSerializer;
+}
+
 public final class io/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools {
 	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/ServerCapabilities$Tools$Companion;
 	public fun <init> ()V

kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/types/capabilities.dsl.kt

@@ -38,7 +38,7 @@ import kotlinx.serialization.json.buildJsonObject
 public class ClientCapabilitiesBuilder @PublishedApi internal constructor() {
     private var sampling: ClientCapabilities.Sampling? = null
     private var roots: ClientCapabilities.Roots? = null
-    private var elicitation: JsonObject? = null
+    private var elicitation: ClientCapabilities.Elicitation? = null
     private var extensions: Map<String, JsonObject>? = null
     private var experimental: JsonObject? = null
 
@@ -47,7 +47,7 @@ public class ClientCapabilitiesBuilder @PublishedApi internal constructor() {
      *
      * Pass `ClientCapabilities.Sampling()` to enable base sampling with no sub-capabilities.
      * Construct `ClientCapabilities.Sampling(tools = EmptyJsonObject, context = EmptyJsonObject)`
-     * directly to enable SEP-1577 sub-capabilities.
+     * directly to enable tools/context sub-capabilities.
      *
      * Example:
      * ```kotlin
@@ -99,26 +99,10 @@ public class ClientCapabilitiesBuilder @PublishedApi internal constructor() {
      *
      * @param value The elicitation capability configuration
      */
-    public fun elicitation(value: JsonObject) {
+    public fun elicitation(value: ClientCapabilities.Elicitation) {
         this.elicitation = value
     }
 
-    /**
-     * Indicates that the client supports elicitation from the server with custom configuration.
-     *
-     * Example:
-     * ```kotlin
-     * capabilities {
-     *     elicitation {
-     *         put("mode", JsonPrimitive("interactive"))
-     *     }
-     * }
-     * ```
-     *
-     * @param block Lambda for building the elicitation configuration
-     */
-    public fun elicitation(block: JsonObjectBuilder.() -> Unit): Unit = elicitation(buildJsonObject(block))
-
     /**
      * Defines extensions that the client supports.
      *

kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/types/capabilities.kt

@@ -41,9 +41,11 @@ public data class Implementation(
  * supports that capability.
  *
  * @property sampling Present if the client supports sampling from an LLM.
- * Use [ClientCapabilities.Sampling] to configure SEP-1577 sub-capabilities (tools, context).
+ * Use [ClientCapabilities.Sampling] to configure tools/context sub-capabilities.
  * @property roots Present if the client supports listing roots.
  * @property elicitation Present if the client supports elicitation from the server.
+ * Use [ClientCapabilities.Elicitation] to configure form/url mode sub-capabilities.
+ * @property tasks Present if the client supports task-augmented requests, listing, or cancellation.
  * @property experimental Experimental, non-standard capabilities that the client supports.
  * Keys are capability names, values are capability-specific configuration objects.
  * @property extensions Optional extensions that the client supports.
@@ -54,23 +56,33 @@ public data class Implementation(
 public data class ClientCapabilities(
     public val sampling: Sampling? = null,
     public val roots: Roots? = null,
-    public val elicitation: JsonObject? = null,
+    public val elicitation: Elicitation? = null,
+    public val tasks: Tasks? = null,
     public val experimental: JsonObject? = null,
     public val extensions: Map<String, JsonObject>? = null,
 ) {
 
     /**
-     * Source-compatibility constructor retaining the pre-SEP-1577 `sampling: JsonObject?`
+     * Source-compatibility constructor retaining the older `sampling: JsonObject?` /
-     * shape. Any non-null [sampling] is converted to an empty [Sampling] (sub-capabilities
+     * `elicitation: JsonObject?` shapes. Any non-null [sampling] is converted to an
-     * cannot be recovered from the old opaque `JsonObject`).
+     * empty [Sampling], and any non-null [elicitation] is converted to an empty
+     * [Elicitation] (sub-capabilities cannot be recovered from the old opaque
+     * `JsonObject`).
      */
     @Deprecated(
-        "ClientCapabilities.sampling is now typed. Pass a ClientCapabilities.Sampling? " +
+        "ClientCapabilities.sampling and ClientCapabilities.elicitation are now typed. " +
+            "Pass typed ClientCapabilities.Sampling? / ClientCapabilities.Elicitation? " +
             "instead of JsonObject?.",
         ReplaceWith(
-            "ClientCapabilities(sampling?.let { ClientCapabilities.Sampling() }, " +
+            "ClientCapabilities(" +
-                "roots, elicitation, experimental, extensions)",
+                "sampling?.let { ClientCapabilities.Sampling() }, " +
+                "roots, " +
+                "elicitation?.let { ClientCapabilities.Elicitation() }, " +
+                "tasks = null, " +
+                "experimental = experimental, " +
+                "extensions = extensions)",
         ),
+        level = DeprecationLevel.WARNING,
     )
     public constructor(
         sampling: JsonObject?,
@@ -81,7 +93,8 @@ public data class ClientCapabilities(
     ) : this(
         sampling = sampling?.let { Sampling() },
         roots = roots,
-        elicitation = elicitation,
+        elicitation = elicitation?.let { Elicitation() },
+        tasks = null,
         experimental = experimental,
         extensions = extensions,
     )
@@ -101,11 +114,11 @@ public data class ClientCapabilities(
 
     /**
      * @property sampling convenience value to enable the base sampling capability with no sub-capabilities
-     * @property elicitation convenience value to enable the elicitation capability
+     * @property elicitation convenience value to enable the elicitation capability with default form mode
      */
     public companion object {
         public val sampling: Sampling = Sampling()
-        public val elicitation: JsonObject = EmptyJsonObject
+        public val elicitation: Elicitation = Elicitation()
     }
 
     /**
@@ -120,6 +133,60 @@ public data class ClientCapabilities(
      */
     @Serializable
     public data class Roots(val listChanged: Boolean? = null)
+
+    /**
+     * Sub-capabilities for elicitation.
+     *
+     * An empty [Elicitation] (both fields null) is equivalent to declaring `form` mode only.
+     *
+     * @property form Present if the client supports form-mode elicitation
+     * (in-band structured data collection).
+     * @property url  Present if the client supports url-mode elicitation
+     * (out-of-band interaction via URL navigation).
+     */
+    @Serializable
+    public data class Elicitation(public val form: JsonObject? = null, public val url: JsonObject? = null)
+
+    /**
+     * Sub-capabilities for tasks (client side).
+     *
+     * Declares which client-side requests can be augmented with task execution,
+     * and whether the client supports listing and cancelling tasks.
+     *
+     * @property list     Present if the client supports the `tasks/list` operation.
+     * @property cancel   Present if the client supports the `tasks/cancel` operation.
+     * @property requests Present if the client supports task-augmented sampling and/or elicitation requests.
+     */
+    @Serializable
+    public data class Tasks(
+        public val list: JsonObject? = null,
+        public val cancel: JsonObject? = null,
+        public val requests: Requests? = null,
+    ) {
+        /**
+         * Task-augmentable client-side request categories.
+         *
+         * @property sampling    Present if the client supports task-augmented `sampling/createMessage` requests.
+         * @property elicitation Present if the client supports task-augmented `elicitation/create` requests.
+         */
+        @Serializable
+        public data class Requests(
+            public val sampling: Sampling? = null,
+            public val elicitation: Elicitation? = null,
+        ) {
+            /**
+             * @property createMessage Present if the client supports task-augmented `sampling/createMessage` requests.
+             */
+            @Serializable
+            public data class Sampling(public val createMessage: JsonObject? = null)
+
+            /**
+             * @property create Present if the client supports task-augmented `elicitation/create` requests.
+             */
+            @Serializable
+            public data class Elicitation(public val create: JsonObject? = null)
+        }
+    }
 }
 
 /**
@@ -137,6 +204,7 @@ public data class ClientCapabilities(
  * @property logging Present if the server supports sending log messages to the client.
  * @property completions Present if the server supports argument autocompletion suggestions.
  * Keys are capability names, values are capability-specific configuration objects.
+ * @property tasks Present if the server supports task-augmented requests, listing, or cancellation.
  * @property experimental Experimental, non-standard capabilities that the server supports.
  * @property extensions Optional extensions that the server supports.
  * Keys are extension identifiers (e.g., `"io.modelcontextprotocol/ui"`),
@@ -149,6 +217,7 @@ public data class ServerCapabilities(
     val prompts: Prompts? = null,
     val logging: JsonObject? = null,
     val completions: JsonObject? = null,
+    val tasks: Tasks? = null,
     val experimental: JsonObject? = null,
     val extensions: Map<String, JsonObject>? = null,
 ) {
@@ -199,4 +268,35 @@ public data class ServerCapabilities(
      */
     @Serializable
     public data class Prompts(val listChanged: Boolean? = null)
+
+    /**
+     * Sub-capabilities for tasks (server side).
+     *
+     * Declares which server-side requests can be augmented with task execution,
+     * and whether the server supports listing and cancelling tasks.
+     *
+     * @property list     Present if the server supports the `tasks/list` operation.
+     * @property cancel   Present if the server supports the `tasks/cancel` operation.
+     * @property requests Present if the server supports task-augmented tool call requests.
+     */
+    @Serializable
+    public data class Tasks(
+        public val list: JsonObject? = null,
+        public val cancel: JsonObject? = null,
+        public val requests: Requests? = null,
+    ) {
+        /**
+         * Task-augmentable server-side request categories.
+         *
+         * @property tools Present if the server supports task-augmented `tools/call` requests.
+         */
+        @Serializable
+        public data class Requests(public val tools: Tools? = null) {
+            /**
+             * @property call Present if the server supports task-augmented `tools/call` requests.
+             */
+            @Serializable
+            public data class Tools(public val call: JsonObject? = null)
+        }
+    }
 }

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/types/CapabilitiesTest.kt

@@ -313,7 +313,7 @@ class CapabilitiesTest {
 
         assertEquals(ClientCapabilities.Sampling(), capabilities.sampling)
         assertEquals(true, capabilities.roots?.listChanged)
-        assertEquals(EmptyJsonObject, capabilities.elicitation)
+        assertEquals(ClientCapabilities.Elicitation(), capabilities.elicitation)
     }
 
     @Test
@@ -804,4 +804,123 @@ class CapabilitiesTest {
         val caps = ClientCapabilities()
         caps.sampling shouldBe null
     }
+
+    @Test
+    fun `should serialize ServerCapabilities with tasks`() {
+        val capabilities = ServerCapabilities(
+            tasks = ServerCapabilities.Tasks(
+                list = EmptyJsonObject,
+                cancel = EmptyJsonObject,
+                requests = ServerCapabilities.Tasks.Requests(
+                    tools = ServerCapabilities.Tasks.Requests.Tools(call = EmptyJsonObject),
+                ),
+            ),
+        )
+        verifySerialization(
+            capabilities,
+            McpJson,
+            """
+            {
+              "tasks": {
+                "list": {},
+                "cancel": {},
+                "requests": {
+                  "tools": {
+                    "call": {}
+                  }
+                }
+              }
+            }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `should deserialize ServerCapabilities with tasks`() {
+        val json = """
+            {
+              "tasks": {
+                "list": {},
+                "requests": {"tools": {"call": {}}}
+              }
+            }
+        """.trimIndent()
+        val capabilities = verifyDeserialization<ServerCapabilities>(McpJson, json)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.list)
+        assertNull(capabilities.tasks?.cancel)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.requests?.tools?.call)
+    }
+
+    @Test
+    fun `should serialize ClientCapabilities with tasks`() {
+        val capabilities = ClientCapabilities(
+            tasks = ClientCapabilities.Tasks(
+                list = EmptyJsonObject,
+                cancel = EmptyJsonObject,
+                requests = ClientCapabilities.Tasks.Requests(
+                    sampling = ClientCapabilities.Tasks.Requests.Sampling(createMessage = EmptyJsonObject),
+                    elicitation = ClientCapabilities.Tasks.Requests.Elicitation(create = EmptyJsonObject),
+                ),
+            ),
+        )
+        verifySerialization(
+            capabilities,
+            McpJson,
+            """
+            {
+              "tasks": {
+                "list": {},
+                "cancel": {},
+                "requests": {
+                  "sampling": {"createMessage": {}},
+                  "elicitation": {"create": {}}
+                }
+              }
+            }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `should serialize ClientCapabilities with structured elicitation form and url`() {
+        val capabilities = ClientCapabilities(
+            elicitation = ClientCapabilities.Elicitation(form = EmptyJsonObject, url = EmptyJsonObject),
+        )
+        verifySerialization(
+            capabilities,
+            McpJson,
+            """
+            {
+              "elicitation": {
+                "form": {},
+                "url": {}
+              }
+            }
+            """.trimIndent(),
+        )
+    }
+
+    @Test
+    fun `should deserialize ClientCapabilities with elicitation and tasks`() {
+        val json = """
+            {
+              "elicitation": {"form": {}, "url": {}},
+              "tasks": {
+                "list": {},
+                "cancel": {},
+                "requests": {
+                  "sampling": {"createMessage": {}},
+                  "elicitation": {"create": {}}
+                }
+              }
+            }
+        """.trimIndent()
+        val capabilities = verifyDeserialization<ClientCapabilities>(McpJson, json)
+        assertEquals(EmptyJsonObject, capabilities.elicitation?.form)
+        assertEquals(EmptyJsonObject, capabilities.elicitation?.url)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.list)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.cancel)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.requests?.sampling?.createMessage)
+        assertEquals(EmptyJsonObject, capabilities.tasks?.requests?.elicitation?.create)
+    }
 }

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/types/dsl/CapabilitiesDslTest.kt

@@ -44,11 +44,7 @@ class CapabilitiesDslTest {
             capabilities {
                 sampling(ClientCapabilities.Sampling(tools = EmptyJsonObject))
                 roots(listChanged = true)
-                elicitation {
+                elicitation(ClientCapabilities.Elicitation(form = EmptyJsonObject, url = EmptyJsonObject))
-                    put("mode", "interactive")
-                    put("timeout", 30)
-                    put("retries", 3)
-                }
                 experimental {
                     put("customFeature", true)
                     put("version", "1.0")
@@ -74,9 +70,8 @@ class CapabilitiesDslTest {
                 listChanged shouldBe true
             }
             elicitation shouldNotBeNull {
-                get("mode")?.jsonPrimitive?.content shouldBe "interactive"
+                form shouldBe EmptyJsonObject
-                get("timeout")?.jsonPrimitive?.content shouldBe "30"
+                url shouldBe EmptyJsonObject
-                get("retries")?.jsonPrimitive?.content shouldBe "3"
             }
             experimental shouldNotBeNull {
                 get("customFeature")?.jsonPrimitive?.content shouldBe "true"

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/types/dsl/InitializeDslTest.kt

@@ -22,9 +22,7 @@ class InitializeDslTest {
             capabilities {
                 sampling(ClientCapabilities.Sampling())
                 roots(listChanged = true)
-                elicitation {
+                elicitation(ClientCapabilities.Elicitation(form = EmptyJsonObject))
-                    put("mode", "interactive")
-                }
                 experimental {
                     put("custom", true)
                 }
@@ -46,7 +44,7 @@ class InitializeDslTest {
         request.params.capabilities.shouldNotBeNull {
             sampling shouldNotBeNull { }
             roots?.listChanged shouldBe true
-            elicitation?.get("mode")?.jsonPrimitive?.content shouldBe "interactive"
+            elicitation?.form shouldBe EmptyJsonObject
             experimental?.get("custom")?.jsonPrimitive?.content shouldBe "true"
             extensions shouldNotBeNull {
                 get("io.modelcontextprotocol/ui") shouldBe EmptyJsonObject
@@ -78,7 +76,7 @@ class InitializeDslTest {
     @Test
     fun `capabilities DSL should support direct typed values`() {
         val samplingValue = ClientCapabilities.Sampling(tools = EmptyJsonObject)
-        val elicitationObj = buildJsonObject { put("key", "value") }
+        val elicitationValue = ClientCapabilities.Elicitation(form = EmptyJsonObject, url = EmptyJsonObject)
         val experimentalObj = buildJsonObject { put("key", "value") }
         val extensionsMap = mapOf(
             "io.modelcontextprotocol/ui" to buildJsonObject { put("key", "value") },
@@ -88,7 +86,7 @@ class InitializeDslTest {
             protocolVersion = "1.0"
             capabilities {
                 sampling(samplingValue)
-                elicitation(elicitationObj)
+                elicitation(elicitationValue)
                 experimental(experimentalObj)
                 extensions(extensionsMap)
             }
@@ -97,7 +95,7 @@ class InitializeDslTest {
 
         request.params.capabilities.shouldNotBeNull {
             sampling shouldBe samplingValue
-            elicitation shouldBe elicitationObj
+            elicitation shouldBe elicitationValue
             experimental shouldBe experimentalObj
             extensions shouldBe extensionsMap
         }

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

@@ -172,6 +172,12 @@ public open class ServerSession(
                 }
             }
 
+            Defined.TasksGet,
+            Defined.TasksResult,
+            Defined.TasksList,
+            Defined.TasksCancel,
+            -> assertTasksCapabilityForMethod(method)
+
             Defined.Ping -> {
                 // No specific capability required
             }
@@ -182,6 +188,28 @@ public open class ServerSession(
         }
     }
 
+    private fun assertTasksCapabilityForMethod(method: Method) {
+        val tasks = clientCapabilities?.tasks
+            ?: error("Client does not support tasks (required for ${method.value})")
+        when (method) {
+            Defined.TasksList -> {
+                if (tasks.list == null) {
+                    error("Client does not support listing tasks (required for ${method.value})")
+                }
+            }
+
+            Defined.TasksCancel -> {
+                if (tasks.cancel == null) {
+                    error("Client does not support cancelling tasks (required for ${method.value})")
+                }
+            }
+
+            else -> {
+                // TasksGet, TasksResult: base tasks capability suffices.
+            }
+        }
+    }
+
     /**
      * Asserts that the server can handle the specified notification method.
      *
@@ -225,6 +253,12 @@ public open class ServerSession(
                 }
             }
 
+            Defined.NotificationsTasksStatus -> {
+                if (serverCapabilities.tasks == null) {
+                    error("Server does not support tasks (required for ${method.value})")
+                }
+            }
+
             Defined.NotificationsCancelled,
             Defined.NotificationsProgress,
             -> {

kotlin-sdk-server/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ServerSessionAssertCapabilityTest.kt

@@ -0,0 +1,147 @@
+package io.modelcontextprotocol.kotlin.sdk.server
+
+import io.kotest.matchers.string.shouldContain
+import io.modelcontextprotocol.kotlin.sdk.shared.Transport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
+import io.modelcontextprotocol.kotlin.sdk.types.ClientCapabilities
+import io.modelcontextprotocol.kotlin.sdk.types.Implementation
+import io.modelcontextprotocol.kotlin.sdk.types.InitializeRequest
+import io.modelcontextprotocol.kotlin.sdk.types.InitializeRequestParams
+import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
+import io.modelcontextprotocol.kotlin.sdk.types.LATEST_PROTOCOL_VERSION
+import io.modelcontextprotocol.kotlin.sdk.types.Method
+import io.modelcontextprotocol.kotlin.sdk.types.RequestId
+import io.modelcontextprotocol.kotlin.sdk.types.ServerCapabilities
+import io.modelcontextprotocol.kotlin.sdk.types.toJSON
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertFailsWith
+
+/**
+ * Tests for the protected helpers [ServerSession.assertCapabilityForMethod] and
+ * [ServerSession.assertNotificationCapability].
+ *
+ * Both helpers are `protected`, so this suite uses a small subclass [TestServerSession]
+ * that re-exports them via [TestServerSession.exposedAssertCapabilityForMethod] and
+ * [TestServerSession.exposedAssertNotificationCapability]. Client capabilities are
+ * seeded by replaying an [InitializeRequest] through [InitializeReplayTransport]:
+ * the transport drives the inbound side of the handshake on `start()`, which causes
+ * the session's internal [Method.Defined.Initialize] handler to populate
+ * [ServerSession.clientCapabilities].
+ */
+class ServerSessionAssertCapabilityTest {
+
+    @Test
+    fun `server TasksGet throws when client has no tasks capability`() = runTest {
+        val session = newTestServerSession(clientCapabilities = ClientCapabilities())
+        val ex = assertFailsWith<IllegalStateException> {
+            session.exposedAssertCapabilityForMethod(Method.Defined.TasksGet)
+        }
+        ex.message.orEmpty() shouldContain "Client does not support tasks"
+    }
+
+    @Test
+    fun `server TasksGet succeeds when client declared tasks`() = runTest {
+        val session = newTestServerSession(
+            clientCapabilities = ClientCapabilities(tasks = ClientCapabilities.Tasks()),
+        )
+        session.exposedAssertCapabilityForMethod(Method.Defined.TasksGet)
+    }
+
+    @Test
+    fun `server TasksList throws when client tasks list is null`() = runTest {
+        val session = newTestServerSession(
+            clientCapabilities = ClientCapabilities(tasks = ClientCapabilities.Tasks()),
+        )
+        val ex = assertFailsWith<IllegalStateException> {
+            session.exposedAssertCapabilityForMethod(Method.Defined.TasksList)
+        }
+        ex.message.orEmpty() shouldContain "Client does not support listing tasks"
+    }
+
+    @Test
+    fun `server TasksCancel throws when client tasks cancel is null`() = runTest {
+        val session = newTestServerSession(
+            clientCapabilities = ClientCapabilities(tasks = ClientCapabilities.Tasks()),
+        )
+        val ex = assertFailsWith<IllegalStateException> {
+            session.exposedAssertCapabilityForMethod(Method.Defined.TasksCancel)
+        }
+        ex.message.orEmpty() shouldContain "Client does not support cancelling tasks"
+    }
+
+    @Test
+    fun `server NotificationsTasksStatus throws when server has no tasks capability`() = runTest {
+        val session = newTestServerSession(serverCapabilities = ServerCapabilities())
+        val ex = assertFailsWith<IllegalStateException> {
+            session.exposedAssertNotificationCapability(Method.Defined.NotificationsTasksStatus)
+        }
+        ex.message.orEmpty() shouldContain "Server does not support tasks"
+    }
+
+    private suspend fun newTestServerSession(
+        clientCapabilities: ClientCapabilities = ClientCapabilities(),
+        serverCapabilities: ServerCapabilities = ServerCapabilities(),
+    ): TestServerSession {
+        val session = TestServerSession(
+            serverInfo = Implementation("test-server", "1.0.0"),
+            options = ServerOptions(capabilities = serverCapabilities),
+            instructions = null,
+        )
+        val transport = InitializeReplayTransport(clientCapabilities)
+        session.connect(transport)
+        return session
+    }
+
+    /**
+     * Test-only [ServerSession] subclass that exposes the protected
+     * [ServerSession.assertCapabilityForMethod] and
+     * [ServerSession.assertNotificationCapability] helpers to the test code.
+     */
+    private class TestServerSession(serverInfo: Implementation, options: ServerOptions, instructions: String?) :
+        ServerSession(serverInfo, options, instructions) {
+        fun exposedAssertCapabilityForMethod(method: Method): Unit = assertCapabilityForMethod(method)
+        fun exposedAssertNotificationCapability(method: Method): Unit = assertNotificationCapability(method)
+    }
+
+    /**
+     * Minimal in-memory [Transport] that drives the server-side initialize handshake.
+     *
+     * On [start], it dispatches an [InitializeRequest] carrying the configured
+     * [clientCapabilities] to the session via [onMessage]. The session's internal
+     * `initialize` handler runs synchronously and populates
+     * [ServerSession.clientCapabilities] before [start] returns. Other JSON-RPC
+     * traffic the session subsequently emits is silently consumed.
+     */
+    private class InitializeReplayTransport(private val clientCapabilities: ClientCapabilities) : Transport {
+        private var onMessageBlock: (suspend (JSONRPCMessage) -> Unit)? = null
+        private var onCloseBlock: (() -> Unit)? = null
+
+        override suspend fun start() {
+            val initializeRequest = InitializeRequest(
+                params = InitializeRequestParams(
+                    protocolVersion = LATEST_PROTOCOL_VERSION,
+                    capabilities = clientCapabilities,
+                    clientInfo = Implementation("mock-client", "1.0.0"),
+                ),
+            ).toJSON().copy(id = RequestId.NumberId(1))
+            onMessageBlock?.invoke(initializeRequest)
+        }
+
+        override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) = Unit
+
+        override suspend fun close() {
+            onCloseBlock?.invoke()
+        }
+
+        override fun onMessage(block: suspend (JSONRPCMessage) -> Unit) {
+            onMessageBlock = block
+        }
+
+        override fun onClose(block: () -> Unit) {
+            onCloseBlock = block
+        }
+
+        override fun onError(block: (Throwable) -> Unit) = Unit
+    }
+}