Add options in Transport.send method

kotlin-sdk-client/api/kotlin-sdk-client.api

@@ -66,14 +66,14 @@ public final class io/modelcontextprotocol/kotlin/sdk/client/SseClientTransport
 	public synthetic fun <init> (Lio/ktor/client/HttpClient;Ljava/lang/String;Lkotlin/time/Duration;Lkotlin/jvm/functions/Function1;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public synthetic fun <init> (Lio/ktor/client/HttpClient;Ljava/lang/String;Lkotlin/time/Duration;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
-	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public fun start (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
 public final class io/modelcontextprotocol/kotlin/sdk/client/StdioClientTransport : io/modelcontextprotocol/kotlin/sdk/shared/AbstractTransport {
 	public fun <init> (Lkotlinx/io/Source;Lkotlinx/io/Sink;)V
 	public fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
-	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public fun start (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
@@ -83,8 +83,8 @@ public final class io/modelcontextprotocol/kotlin/sdk/client/StreamableHttpClien
 	public fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public final fun getProtocolVersion ()Ljava/lang/String;
 	public final fun getSessionId ()Ljava/lang/String;
+	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public final fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
-	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public static synthetic fun send$default (Lio/modelcontextprotocol/kotlin/sdk/client/StreamableHttpClientTransport;Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/coroutines/Continuation;ILjava/lang/Object;)Ljava/lang/Object;
 	public final fun setProtocolVersion (Ljava/lang/String;)V
 	public fun start (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;

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

@@ -15,6 +15,7 @@ import io.ktor.http.append
 import io.ktor.http.isSuccess
 import io.ktor.http.protocolWithAuthority
 import io.modelcontextprotocol.kotlin.sdk.shared.AbstractTransport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
 import io.modelcontextprotocol.kotlin.sdk.types.McpJson
 import kotlinx.coroutines.CancellationException
@@ -98,7 +99,7 @@ public class SseClientTransport(
     }
 
     @OptIn(ExperimentalCoroutinesApi::class)
-    override suspend fun send(message: JSONRPCMessage) {
+    override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
         check(initialized.load()) { "SseClientTransport is not initialized!" }
         check(job?.isActive == true) { "SseClientTransport is closed!" }
         check(endpoint.isCompleted) { "Not connected!" }

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

@@ -4,6 +4,7 @@ import io.github.oshai.kotlinlogging.KotlinLogging
 import io.modelcontextprotocol.kotlin.sdk.internal.IODispatcher
 import io.modelcontextprotocol.kotlin.sdk.shared.AbstractTransport
 import io.modelcontextprotocol.kotlin.sdk.shared.ReadBuffer
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
 import io.modelcontextprotocol.kotlin.sdk.shared.serializeMessage
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
 import kotlinx.coroutines.CoroutineName
@@ -100,7 +101,7 @@ public class StdioClientTransport(private val input: Source, private val output:
         }
     }
 
-    override suspend fun send(message: JSONRPCMessage) {
+    override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
         if (!initialized.load()) {
             error("Transport not started")
         }

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

@@ -22,6 +22,7 @@ import io.ktor.http.contentType
 import io.ktor.http.isSuccess
 import io.ktor.utils.io.readUTF8Line
 import io.modelcontextprotocol.kotlin.sdk.shared.AbstractTransport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCNotification
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCRequest
@@ -89,8 +90,8 @@ public class StreamableHttpClientTransport(
     /**
      * Sends a single message with optional resumption support
      */
-    override suspend fun send(message: JSONRPCMessage) {
-        send(message, null)
+    override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
+        send(message, options?.resumptionToken, options?.onResumptionToken)
     }
 
     /**

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

@@ -1,6 +1,7 @@
 package io.modelcontextprotocol.kotlin.sdk.client
 
 import io.modelcontextprotocol.kotlin.sdk.shared.Transport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
 import io.modelcontextprotocol.kotlin.sdk.types.CallToolResult
 import io.modelcontextprotocol.kotlin.sdk.types.Implementation
 import io.modelcontextprotocol.kotlin.sdk.types.InitializeResult
@@ -25,7 +26,7 @@ class MockTransport : Transport {
 
     override suspend fun start() = Unit
 
-    override suspend fun send(message: JSONRPCMessage) {
+    override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
         mutex.withLock {
             _sentMessages += message
         }

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

@@ -8,6 +8,7 @@ import io.modelcontextprotocol.kotlin.sdk.JSONRPCRequest
 import io.modelcontextprotocol.kotlin.sdk.JSONRPCResponse
 import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
 import io.modelcontextprotocol.kotlin.sdk.shared.Transport
+import io.modelcontextprotocol.kotlin.sdk.shared.TransportSendOptions
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 
@@ -25,7 +26,7 @@ class OldSchemaMockTransport : Transport {
 
     override suspend fun start() = Unit
 
-    override suspend fun send(message: JSONRPCMessage) {
+    override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
         mutex.withLock {
             _sentMessages += message
         }

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

@@ -433,7 +433,8 @@ public abstract class io/modelcontextprotocol/kotlin/sdk/shared/Protocol {
 	public final fun getRequestHandlers ()Ljava/util/Map;
 	public final fun getResponseHandlers ()Ljava/util/Map;
 	public final fun getTransport ()Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;
-	public final fun notification (Lio/modelcontextprotocol/kotlin/sdk/types/Notification;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public final fun notification (Lio/modelcontextprotocol/kotlin/sdk/types/Notification;Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public static synthetic fun notification$default (Lio/modelcontextprotocol/kotlin/sdk/shared/Protocol;Lio/modelcontextprotocol/kotlin/sdk/types/Notification;Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Lkotlin/coroutines/Continuation;ILjava/lang/Object;)Ljava/lang/Object;
 	public fun onClose ()V
 	public fun onError (Ljava/lang/Throwable;)V
 	public final fun removeNotificationHandler (Lio/modelcontextprotocol/kotlin/sdk/types/Method;)V
@@ -476,13 +477,13 @@ public final class io/modelcontextprotocol/kotlin/sdk/shared/RequestHandlerExtra
 	public fun <init> ()V
 }
 
-public final class io/modelcontextprotocol/kotlin/sdk/shared/RequestOptions {
-	public synthetic fun <init> (Lkotlin/jvm/functions/Function1;JILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public synthetic fun <init> (Lkotlin/jvm/functions/Function1;JLkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public final fun component1 ()Lkotlin/jvm/functions/Function1;
-	public final fun component2-UwyO8pc ()J
-	public final fun copy-HG0u8IE (Lkotlin/jvm/functions/Function1;J)Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;
-	public static synthetic fun copy-HG0u8IE$default (Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;Lkotlin/jvm/functions/Function1;JILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;
+public final class io/modelcontextprotocol/kotlin/sdk/shared/RequestOptions : io/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions {
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;JILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;JLkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component4 ()Lkotlin/jvm/functions/Function1;
+	public final fun component5-UwyO8pc ()J
+	public final fun copy-9VgGkz4 (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;J)Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;
+	public static synthetic fun copy-9VgGkz4$default (Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;JILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/shared/RequestOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getOnProgress ()Lkotlin/jvm/functions/Function1;
 	public final fun getTimeout-UwyO8pc ()J
@@ -495,16 +496,38 @@ public abstract interface class io/modelcontextprotocol/kotlin/sdk/shared/Transp
 	public abstract fun onClose (Lkotlin/jvm/functions/Function0;)V
 	public abstract fun onError (Lkotlin/jvm/functions/Function1;)V
 	public abstract fun onMessage (Lkotlin/jvm/functions/Function2;)V
-	public abstract fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public abstract fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public static synthetic fun send$default (Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;ILjava/lang/Object;)Ljava/lang/Object;
 	public abstract fun start (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
+public final class io/modelcontextprotocol/kotlin/sdk/shared/Transport$DefaultImpls {
+	public static synthetic fun send$default (Lio/modelcontextprotocol/kotlin/sdk/shared/Transport;Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;ILjava/lang/Object;)Ljava/lang/Object;
+}
+
+public class io/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions {
+	public fun <init> ()V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;)V
+	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun component1 ()Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;
+	public final fun component2 ()Ljava/lang/String;
+	public final fun component3 ()Lkotlin/jvm/functions/Function1;
+	public fun copy (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;)Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;
+	public static synthetic fun copy$default (Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;
+	public fun equals (Ljava/lang/Object;)Z
+	public final fun getOnResumptionToken ()Lkotlin/jvm/functions/Function1;
+	public final fun getRelatedRequestId ()Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;
+	public final fun getResumptionToken ()Ljava/lang/String;
+	public fun hashCode ()I
+	public fun toString ()Ljava/lang/String;
+}
+
 public abstract class io/modelcontextprotocol/kotlin/sdk/shared/WebSocketMcpTransport : io/modelcontextprotocol/kotlin/sdk/shared/AbstractTransport {
 	public fun <init> ()V
 	public fun close (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	protected abstract fun getSession ()Lio/ktor/websocket/WebSocketSession;
 	protected abstract fun initializeSession (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
-	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun send (Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage;Lio/modelcontextprotocol/kotlin/sdk/shared/TransportSendOptions;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 	public fun start (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 

kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/Protocol.kt

@@ -93,22 +93,58 @@ public val DEFAULT_REQUEST_TIMEOUT: Duration = 60.seconds
 
 /**
  * Options that can be given per request.
+ *
+ * @property relatedRequestId if present,
+ * `relatedRequestId` is used to indicate to the transport which incoming request to associate this outgoing message with.
+ * @property resumptionToken the resumption token used to continue long-running requests that were interrupted.
+ * This allows clients to reconnect and continue from where they left off, if supported by the transport.
+ * @property onResumptionToken a callback that is invoked when the resumption token changes, if supported by the transport.
+ * This allows clients to persist the latest token for potential reconnection.
+ * @property onProgress callback for progress notifications.
+ * If set, requests progress notifications from the remote end (if supported).
+ * When progress notifications are received, this callback will be invoked.
+ * @property timeout a timeout for this request.
+ * If exceeded, a McpException with code `RequestTimeout` will be raised from request().
+ * If not specified, `DEFAULT_REQUEST_TIMEOUT` will be used as the timeout.
  */
-public data class RequestOptions(
-    /**
-     * If set, requests progress notifications from the remote end (if supported).
-     * When progress notifications are received, this callback will be invoked.
-     */
-    val onProgress: ProgressCallback? = null,
+public class RequestOptions(
+    relatedRequestId: RequestId? = null,
+    resumptionToken: String? = null,
+    onResumptionToken: ((String) -> Unit)? = null,
+    public val onProgress: ProgressCallback? = null,
+    public val timeout: Duration = DEFAULT_REQUEST_TIMEOUT,
+) : TransportSendOptions(relatedRequestId, resumptionToken, onResumptionToken) {
+    public operator fun component4(): ProgressCallback? = onProgress
+    public operator fun component5(): Duration = timeout
+
+    public fun copy(
+        relatedRequestId: RequestId? = this.relatedRequestId,
+        resumptionToken: String? = this.resumptionToken,
+        onResumptionToken: ((String) -> Unit)? = this.onResumptionToken,
+        onProgress: ProgressCallback? = this.onProgress,
+        timeout: Duration = this.timeout,
+    ): RequestOptions = RequestOptions(relatedRequestId, resumptionToken, onResumptionToken, onProgress, timeout)
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || this::class != other::class) return false
+        if (!super.equals(other)) return false
+
+        other as RequestOptions
+
+        return onProgress == other.onProgress && timeout == other.timeout
+    }
 
-    /**
-     * A timeout for this request. If exceeded, an McpError with code `RequestTimeout`
-     * will be raised from request().
-     *
-     * If not specified, `DEFAULT_REQUEST_TIMEOUT` will be used as the timeout.
-     */
-    val timeout: Duration = DEFAULT_REQUEST_TIMEOUT,
-)
+    override fun hashCode(): Int {
+        var result = super.hashCode()
+        result = 31 * result + (onProgress?.hashCode() ?: 0)
+        result = 31 * result + timeout.hashCode()
+        return result
+    }
+
+    override fun toString(): String =
+        "RequestOptions(relatedRequestId=$relatedRequestId, resumptionToken=$resumptionToken, onResumptionToken=$onResumptionToken, onProgress=$onProgress, timeout=$timeout)"
+}
 
 /**
  * Extra data given to request handlers.
@@ -456,11 +492,9 @@ public abstract class Protocol(@PublishedApi internal val options: ProtocolOptio
                 ),
             )
 
-            val serialized = JSONRPCNotification(
-                notification.method.value,
-                params = McpJson.encodeToJsonElement(notification),
-            )
-            transport.send(serialized)
+            val jsonRpcNotification = notification.toJSON()
+
+            transport.send(jsonRpcNotification, options)
 
             result.completeExceptionally(reason)
         }
@@ -469,7 +503,7 @@ public abstract class Protocol(@PublishedApi internal val options: ProtocolOptio
         try {
             withTimeout(timeout) {
                 logger.trace { "Sending request message with id: $jsonRpcRequestId" }
-                this@Protocol.transport?.send(jsonRpcRequest)
+                this@Protocol.transport?.send(jsonRpcRequest, options)
             }
             return result.await()
         } catch (cause: TimeoutCancellationException) {
@@ -489,13 +523,14 @@ public abstract class Protocol(@PublishedApi internal val options: ProtocolOptio
     /**
      * Emits a notification, which is a one-way message that does not expect a response.
      */
-    public suspend fun notification(notification: Notification) {
+    public suspend fun notification(notification: Notification, relatedRequestId: RequestId? = null) {
         logger.trace { "Sending notification: ${notification.method}" }
         val transport = this.transport ?: error("Not connected")
         assertNotificationCapability(notification.method)
+        val sendOptions = relatedRequestId?.let { TransportSendOptions(relatedRequestId = it) }
+        val jsonRpcNotification = notification.toJSON()
 
-        val message = notification.toJSON()
-        transport.send(message)
+        transport.send(jsonRpcNotification, sendOptions)
     }
 
     /**

kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/Transport.kt

@@ -18,8 +18,12 @@ public interface Transport {
 
     /**
      * Sends a JSON-RPC message (request or response).
+     *
+     * @property message The JSON-RPC message to send, either a request or a response.
+     * @property options Optional transport-specific options that control sending behavior.
+     * Different transport implementations may support different options.
      */
-    public suspend fun send(message: JSONRPCMessage)
+    public suspend fun send(message: JSONRPCMessage, options: TransportSendOptions? = null)
 
     /**
      * Closes the connection.