Add convenience constructors to JSONRPCRequest (#336)

- Add convenience constructors to JSONRPCRequest
- Make UUID string a default JSONRPCRequest

## Motivation and Context
To create request objects more easily

## How Has This Been Tested?
Unit tests

## Breaking Changes
No, this is a new API

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

Author: kpavlov

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

@@ -17,7 +17,6 @@ import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCNotification
 import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCRequest
 import io.modelcontextprotocol.kotlin.sdk.types.McpJson
-import io.modelcontextprotocol.kotlin.sdk.types.RequestId
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.test.runTest
@@ -50,7 +49,7 @@ class StreamableHttpClientTransportTest {
     @Test
     fun testSendJsonRpcMessage() = runTest {
         val message = JSONRPCRequest(
-            id = RequestId.StringId("test-id"),
+            id = "test-id",
             method = "test",
             params = buildJsonObject { },
         )
@@ -78,7 +77,7 @@ class StreamableHttpClientTransportTest {
     @Test
     fun testStoreSessionId() = runTest {
         val initMessage = JSONRPCRequest(
-            id = RequestId.StringId("test-id"),
+            id = "test-id",
             method = "initialize",
             params = buildJsonObject {
                 put(

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

@@ -2118,8 +2118,14 @@ public final class io/modelcontextprotocol/kotlin/sdk/types/JSONRPCNotification$
 
 public final class io/modelcontextprotocol/kotlin/sdk/types/JSONRPCRequest : io/modelcontextprotocol/kotlin/sdk/types/JSONRPCMessage {
 	public static final field Companion Lio/modelcontextprotocol/kotlin/sdk/types/JSONRPCRequest$Companion;
+	public fun <init> (JLjava/lang/String;Lkotlinx/serialization/json/JsonElement;)V
+	public synthetic fun <init> (JLjava/lang/String;Lkotlinx/serialization/json/JsonElement;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;)V
 	public fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlinx/serialization/json/JsonElement;)V
 	public synthetic fun <init> (Lio/modelcontextprotocol/kotlin/sdk/types/RequestId;Ljava/lang/String;Lkotlinx/serialization/json/JsonElement;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;Lkotlinx/serialization/json/JsonElement;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lkotlinx/serialization/json/JsonElement;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 ()Lkotlinx/serialization/json/JsonElement;

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

@@ -8,15 +8,14 @@ import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.decodeFromJsonElement
 import kotlinx.serialization.json.encodeToJsonElement
-import kotlin.concurrent.atomics.AtomicLong
 import kotlin.concurrent.atomics.ExperimentalAtomicApi
-import kotlin.concurrent.atomics.incrementAndFetch
 import kotlin.jvm.JvmInline
+import kotlin.jvm.JvmOverloads
+import kotlin.uuid.ExperimentalUuidApi
+import kotlin.uuid.Uuid
 
 public const val JSONRPC_VERSION: String = "2.0"
 
-private val REQUEST_MESSAGE_ID: AtomicLong = AtomicLong(0L)
-
 public fun RequestId(value: String): RequestId = RequestId.StringId(value)
 
 public fun RequestId(value: Long): RequestId = RequestId.NumberId(value)
@@ -94,23 +93,50 @@ public sealed interface JSONRPCMessage {
  * A request that expects a response.
  *
  * Requests are identified by a unique [id] and specify a [method] to invoke.
- * The server or client (depending on direction) must respond with either a
+ * The server or client (depending on a direction) must respond with either a
  * [JSONRPCResponse] or [JSONRPCError] that has the same [id].
  *
  * @property jsonrpc Always "2.0" to indicate JSON-RPC 2.0 protocol.
  * @property id A unique identifier for this request. The response will include the same ID.
- * Can be a string or number.
+ * Can be a string or number. UUID string is used by default.
  * @property method The name of the method to invoke (e.g., "tools/list", "resources/read").
  * @property params Optional parameters for the method. Structure depends on the specific method.
  */
 @Serializable
-public data class JSONRPCRequest(
-    val id: RequestId = RequestId(REQUEST_MESSAGE_ID.incrementAndFetch()),
+@OptIn(ExperimentalUuidApi::class)
+public data class JSONRPCRequest @JvmOverloads public constructor(
+    val id: RequestId = RequestId(Uuid.random().toHexString()),
     val method: String,
     val params: JsonElement? = null,
 ) : JSONRPCMessage {
     @EncodeDefault
     override val jsonrpc: String = JSONRPC_VERSION
+
+    /**
+     * Secondary constructor for creating a `JSONRPCRequest` using a string-based ID.
+     *
+     * @param id The string ID for the request.
+     * @param method The method name for the request.
+     * @param params The parameters for the request as a JSON element. Defaults to `null`.
+     */
+    public constructor(
+        id: String,
+        method: String,
+        params: JsonElement? = null,
+    ) : this(id = RequestId.StringId(id), method = method, params = params)
+
+    /**
+     * Constructs a JSON-RPC request using a numerical ID, method name, and optional parameters.
+     *
+     * @param id The numerical ID for the request.
+     * @param method The method name for the request.
+     * @param params The parameters for the request as a JSON element. Defaults to `null`.
+     */
+    public constructor(
+        id: Long,
+        method: String,
+        params: JsonElement? = null,
+    ) : this(id = RequestId.NumberId(id), method = method, params = params)
 }
 
 // ============================================================================
@@ -207,6 +233,7 @@ public data class RPCError(val code: Int, val message: String, val data: JsonEle
         public const val REQUEST_TIMEOUT: Int = -32001
 
         // Standard JSON-RPC 2.0 error codes
+
         /** Invalid JSON was received */
         public const val PARSE_ERROR: Int = -32700
 

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

@@ -1,6 +1,8 @@
 package io.modelcontextprotocol.kotlin.sdk.types
 
 import io.kotest.assertions.json.shouldEqualJson
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.types.shouldBeSameInstanceAs
 import kotlinx.serialization.json.boolean
 import kotlinx.serialization.json.buildJsonObject
 import kotlinx.serialization.json.int
@@ -398,4 +400,34 @@ class JsonRpcTest {
             }
         """.trimIndent()
     }
+
+    @Test
+    fun `should create JSONRPCRequest with string ID`() {
+        val params = buildJsonObject {
+            put("foo", "bar")
+        }
+        val request = JSONRPCRequest(
+            id = "req-42",
+            method = "notifications/log",
+            params = params,
+        )
+        request.id shouldBe RequestId("req-42")
+        request.method shouldBe "notifications/log"
+        request.params shouldBeSameInstanceAs params
+    }
+
+    @Test
+    fun `should create JSONRPCRequest with numeric ID`() {
+        val params = buildJsonObject {
+            put("foo", "bar")
+        }
+        val request = JSONRPCRequest(
+            id = 42,
+            method = "notifications/log",
+            params = params,
+        )
+        request.id shouldBe RequestId(42)
+        request.method shouldBe "notifications/log"
+        request.params shouldBeSameInstanceAs params
+    }
 }