112 changed files with 675 additions and 7193 deletions
--- a/.github/workflows/apidocs.yaml
+++ b/.github/workflows/apidocs.yaml
@ -24,17 +24,17 @@ jobs:

    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}
          cache: gradle

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6

      - name: Generate Dokka Site
        run: |-
--- a/.github/workflows/automations.yml
+++ b/.github/workflows/automations.yml
@ -27,7 +27,7 @@ jobs:
    name: Mark/unmark stale PRs and issues
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/stale@v11
+    - uses: actions/stale@v10
      with:
        debug-only: ${{ env.DRY_RUN }}
        exempt-draft-pr: true
@ -66,7 +66,7 @@ jobs:
    name: Close stale PRs and issues
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/stale@v11
+    - uses: actions/stale@v10
      with:
        debug-only: ${{ env.DRY_RUN }}
        only-labels: 'stale'
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@ -43,17 +43,17 @@ jobs:
            max-workers: 2

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Set up Node.js
        if: matrix.os == 'ubuntu-latest'
-        uses: actions/setup-node@v7
+        uses: actions/setup-node@v6
        with:
          node-version: '22' # increase only after https://github.com/nodejs/node/issues/56645 will be fixed

@ -63,7 +63,7 @@ jobs:
        run: npm ci

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          validate-wrappers: true
          add-job-summary: 'always'
@ -126,16 +126,16 @@ jobs:
      contents: read

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          validate-wrappers: true
          add-job-summary: 'always'
@ -168,16 +168,16 @@ jobs:
    name: "Build Sample: ${{ matrix.sample }}"
    timeout-minutes: 10
    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          add-job-summary: 'always'
          cache-read-only: true
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@ -25,22 +25,22 @@ jobs:

    steps:
      - name: Checkout repository
-        uses: actions/checkout@v7
+        uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          distribution: ${{ env.JAVA_DISTRIBUTION }}
          java-version: ${{ env.JAVA_VERSION }}

      - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.38.0
+        uses: github/codeql-action/init@v4
        with:
          languages: java-kotlin
          build-mode: manual

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          validate-wrappers: true
          cache-read-only: true
@ -52,6 +52,6 @@ jobs:
            --no-daemon --rerun-tasks --stacktrace

      - name: Analyze
-        uses: github/codeql-action/analyze@v4.38.0
+        uses: github/codeql-action/analyze@v4
        with:
          category: '/language:java-kotlin'
--- a/.github/workflows/conformance.yml
+++ b/.github/workflows/conformance.yml
@ -25,16 +25,16 @@ jobs:
    timeout-minutes: 20

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          cache-read-only: ${{ github.ref != 'refs/heads/main' }}

@ -76,16 +76,16 @@ jobs:
          - sse-retry

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          cache-read-only: ${{ github.ref != 'refs/heads/main' }}

@ -107,16 +107,16 @@ jobs:
    timeout-minutes: 20

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          cache-read-only: ${{ github.ref != 'refs/heads/main' }}

@ -146,16 +146,16 @@ jobs:
          - auth/cross-app-access-complete-flow

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          cache-read-only: ${{ github.ref != 'refs/heads/main' }}

--- a/.github/workflows/gradle-publish.yml
+++ b/.github/workflows/gradle-publish.yml
@ -17,20 +17,20 @@ jobs:
      packages: write

    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
      - name: Set up JDK 21
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: '21'
          distribution: 'temurin'

      - name: Set up Node.js
-        uses: actions/setup-node@v7
+        uses: actions/setup-node@v6
        with:
          node-version: '22' # increase only after https://github.com/nodejs/node/issues/56645 will be fixed

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6

      - name: Check
        run: ./gradlew check --no-configuration-cache
--- a/.github/workflows/samples.yml
+++ b/.github/workflows/samples.yml
@ -36,16 +36,16 @@ jobs:
    name: Build Sample (${{ matrix.sample }})
    timeout-minutes: 10
    steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6

      - name: Set up JDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v6
+        uses: actions/setup-java@v5
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: ${{ env.JAVA_DISTRIBUTION }}

      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v6.3.0
+        uses: gradle/actions/setup-gradle@v6
        with:
          validate-wrappers: true
          add-job-summary: 'always'
--- a/README.md
+++ b/README.md
@ -729,7 +729,7 @@ val client = Client(
 )

 client.setRequestHandler<CreateMessageRequest>(Method.Defined.SamplingCreateMessage) { request, _ ->
-    val content = request.messages.lastOrNull()?.content?.firstOrNull()
+    val content = request.messages.lastOrNull()?.content
    val prompt = if (content is TextContent) content.text else "your topic"
    CreateMessageResult(
        model = "gpt-4o-mini",
--- a/config/detekt/detekt.yml
+++ b/config/detekt/detekt.yml
@ -416,6 +416,7 @@ potential-bugs:
  Deprecation:
    active: false
    aliases: ['DEPRECATION']
+    excludeImportStatements: false
  DontDowncastCollectionTypes:
    active: false
  DoubleMutabilityForCollection:
--- a/conformance-test/src/main/kotlin/io/modelcontextprotocol/kotlin/sdk/conformance/ConformanceTools.kt
+++ b/conformance-test/src/main/kotlin/io/modelcontextprotocol/kotlin/sdk/conformance/ConformanceTools.kt
@ -179,13 +179,7 @@ fun Server.registerConformanceTools() {
                ),
            ),
        )
-        val sampledText = result.content.joinToString("\n") { content ->
-            when (content) {
-                is TextContent -> content.text
-                else -> "Non-text sampling content: ${content::class.simpleName}"
-            }
-        }
-        CallToolResult(listOf(TextContent(sampledText)))
+        CallToolResult(listOf(TextContent(result.content.joinToString("\n") { it.toString() })))
    }

    // 9. Elicitation
--- a/gradle.properties
+++ b/gradle.properties
@ -8,4 +8,4 @@ kotlin.daemon.jvmargs=-Xmx4G
 kotlin.native.ignoreDisabledTargets=true

 group=io.modelcontextprotocol
-version=0.15.0
+version=0.13.0
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@ -1,28 +1,28 @@
 [versions]
 # plugins version
-atomicfu = "0.33.0"
-binaryCompatibilityValidatorPlugin = "0.18.2"
-detekt = "2.0.0-alpha.6"
+atomicfu = "0.32.1"
+binaryCompatibilityValidatorPlugin = "0.18.1"
+detekt = "2.0.0-alpha.3"
 dokka = "2.2.0"
-kotlin = "2.4.10"
-kover = "0.9.9"
+kotlin = "2.3.21"
+kover = "0.9.8"
 ktlint = "14.2.0"
 knit = "0.5.1"
-mavenPublish = "0.37.0"
-netty = "4.2.18.Final"
+mavenPublish = "0.36.0"
+netty = "4.2.14.Final"

 # libraries version
 awaitility = "4.3.0"
-collections-immutable = "0.5.2"
+collections-immutable = "0.4.0"
 coroutines = "1.11.0"
-kotest = "6.2.5"
-kotlinx-io = "0.9.1"
-ktor = "3.5.2"
-logging = "8.0.4"
-mockk = "1.14.11"
+kotest = "6.1.11"
+kotlinx-io = "0.9.0"
+ktor = "3.4.3"
+logging = "8.0.03"
+mockk = "1.14.9"
 serialization = "1.11.0"
-slf4j = "2.0.19"
-logback = "1.6.3"
+slf4j = "2.0.18"
+logback = "1.5.32"
 junit = "5.14.4"

 [libraries]
--- a/gradle/wrapper/gradle-wrapper.jar
+++ b/gradle/wrapper/gradle-wrapper.jar
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
 networkTimeout=10000
 retries=0
 retryBackOffMs=500
--- a/4
+++ b/4
@ -20,7 +20,7 @@

 ##############################################################################
 #
-#   gradlew start up script for POSIX generated by Gradle.
+#   Gradle start up script for POSIX generated by Gradle.
 #
 #   Important for running:
 #
@ -29,7 +29,7 @@
 #       bash, then to run this script, type that shell name before the whole
 #       command line, like:
 #
-#           ksh gradlew
+#           ksh Gradle
 #
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:
--- a/gradlew.bat
+++ b/gradlew.bat
@ -19,7 +19,7 @@
@if "%DEBUG%"=="" @echo off
@rem ##########################################################################
@rem
-@rem  gradlew startup script for Windows
+@rem  Gradle startup script for Windows
@rem
@rem ##########################################################################

@ -72,7 +72,7 @@ echo location of your Java installation. 1>&2



-@rem Execute gradlew
+@rem Execute Gradle
@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
@rem which allows us to clear the local environment before executing the java command
 endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
--- a/integration-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientTest.kt
+++ b/integration-test/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/ClientTest.kt
@ -14,17 +14,13 @@ import io.modelcontextprotocol.kotlin.sdk.types.CreateMessageResult
 import io.modelcontextprotocol.kotlin.sdk.types.DoubleSchema
 import io.modelcontextprotocol.kotlin.sdk.types.ElicitRequestFormParams
 import io.modelcontextprotocol.kotlin.sdk.types.ElicitRequestParams
-import io.modelcontextprotocol.kotlin.sdk.types.ElicitRequestURLParams
 import io.modelcontextprotocol.kotlin.sdk.types.ElicitResult
-import io.modelcontextprotocol.kotlin.sdk.types.ElicitationCompleteNotification
-import io.modelcontextprotocol.kotlin.sdk.types.ElicitationCompleteNotificationParams
 import io.modelcontextprotocol.kotlin.sdk.types.EmptyJsonObject
 import io.modelcontextprotocol.kotlin.sdk.types.Implementation
 import io.modelcontextprotocol.kotlin.sdk.types.InitializeRequest
 import io.modelcontextprotocol.kotlin.sdk.types.InitializeResult
 import io.modelcontextprotocol.kotlin.sdk.types.IntegerSchema
 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.JSONRPCResponse
 import io.modelcontextprotocol.kotlin.sdk.types.LATEST_PROTOCOL_VERSION
@ -50,10 +46,8 @@ import io.modelcontextprotocol.kotlin.sdk.types.Tool
 import io.modelcontextprotocol.kotlin.sdk.types.ToolSchema
 import io.modelcontextprotocol.kotlin.sdk.types.UntitledMultiSelectEnumSchema
 import io.modelcontextprotocol.kotlin.sdk.types.UntitledSingleSelectEnumSchema
-import io.modelcontextprotocol.kotlin.sdk.types.UrlElicitationRequiredException
 import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.TimeoutCancellationException
-import kotlinx.coroutines.awaitCancellation
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.joinAll
@ -73,7 +67,6 @@ import kotlin.test.assertIs
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 import kotlin.test.fail
-import kotlin.time.Duration.Companion.seconds

 class ClientTest {
    @Test
@ -546,15 +539,6 @@ class ClientTest {

        val serverSession = serverSessionResult.await()

-        // Register the tap after createSession so it chains onto the session's subscription instead
-        // of pre-empting the handshake.
-        val cancelledOnWire = CompletableDeferred<Unit>()
-        serverTransport.onMessage { message ->
-            if (message is JSONRPCNotification && message.method == Method.Defined.NotificationsCancelled.value) {
-                cancelledOnWire.complete(Unit)
-            }
-        }
-
        serverSession.setRequestHandler<ListResourcesRequest>(Method.Defined.ResourcesList) { _, _ ->
            // Simulate delay
            def.complete(Unit)
@ -580,7 +564,6 @@ class ClientTest {
        def.await()
        runCatching { job.cancel("Cancelled by test") }
        defCancel.await()
-        cancelledOnWire.await()
        defTimeOut.await()
    }

@ -619,9 +602,17 @@ class ClientTest {

        val serverSession = serverSessionResult.await()
        serverSession.setRequestHandler<ListResourcesRequest>(Method.Defined.ResourcesList) { _, _ ->
-            // Never respond: the handler runs on a real dispatcher while the 1 ms timeout runs on the
-            // virtual test clock, so a real-time delay could race it. Parking keeps the test deterministic.
-            awaitCancellation()
+            // Simulate a delayed response
+            // Wait ~100ms unless canceled
+            try {
+                withTimeout(100L) {
+                    // Just delay here, if timeout is 0 on the client side, this won't return in time
+                    delay(100)
+                }
+            } catch (_: Exception) {
+                // If aborted, just rethrow or return early
+            }
+            ListResourcesResult(resources = emptyList())
        }

        // Request with 1 msec timeout should fail immediately
@ -900,8 +891,8 @@ class ClientTest {
            ),
        )

-        // The handler runs on Dispatchers.Default after concurrent dispatch is enabled; await the deferred.
-        val rootListChangedReceived = CompletableDeferred<Unit>()
+        // Track notifications
+        var rootListChangedNotificationReceived = false

        val serverSessionResult = CompletableDeferred<ServerSession>()

@ -920,13 +911,16 @@ class ClientTest {
        serverSession.setNotificationHandler<RootsListChangedNotification>(
            Method.Defined.NotificationsRootsListChanged,
        ) {
-            rootListChangedReceived.complete(Unit)
+            rootListChangedNotificationReceived = true
            CompletableDeferred(Unit)
        }

        client.sendRootsListChanged()

-        withTimeout(5.seconds) { rootListChangedReceived.await() }
+        assertTrue(
+            rootListChangedNotificationReceived,
+            "Notification should be sent when sendRootsListChanged is called",
+        )
    }

    @Test
@ -1124,103 +1118,6 @@ class ClientTest {
        assertEquals(elicitationResultContent, result.content)
    }

-    @Test
-    fun `should reject accepted elicitation content that does not match requested schema`() = runTest {
-        val requestedSchema = ElicitRequestParams.RequestedSchema(
-            properties = mapOf("name" to StringSchema()),
-            required = listOf("name"),
-        )
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Accept, content = buildJsonObject { put("name", 42) })
-        }
-
-        val exception = assertFailsWith<McpException> {
-            serverSession.createElicitation(message = "mismatch", requestedSchema = requestedSchema)
-        }
-        assertTrue(
-            exception.message.orEmpty()
-                .startsWith("Elicitation response content does not match requested schema: "),
-            "Unexpected message: ${exception.message}",
-        )
-        assertTrue("'name' must be string" in exception.message.orEmpty(), "Unexpected message: ${exception.message}")
-
-        client.close()
-    }
-
-    @Test
-    fun `should reject accepted elicitation without content when schema has required properties`() = runTest {
-        val requestedSchema = ElicitRequestParams.RequestedSchema(
-            properties = mapOf("name" to StringSchema()),
-            required = listOf("name"),
-        )
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Accept, content = null)
-        }
-
-        val exception = assertFailsWith<McpException> {
-            serverSession.createElicitation(message = "no content", requestedSchema = requestedSchema)
-        }
-        assertTrue(
-            "must have required property 'name'" in exception.message.orEmpty(),
-            "Unexpected message: ${exception.message}",
-        )
-
-        client.close()
-    }
-
-    @Test
-    fun `should accept elicitation without content when schema has no required properties`() = runTest {
-        val requestedSchema = ElicitRequestParams.RequestedSchema(
-            properties = mapOf("name" to StringSchema()),
-        )
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Accept, content = null)
-        }
-
-        val result = serverSession.createElicitation(message = "no required", requestedSchema = requestedSchema)
-
-        assertEquals(ElicitResult.Action.Accept, result.action)
-        assertNull(result.content)
-
-        client.close()
-    }
-
-    @Test
-    fun `should pass through declined elicitation without validation`() = runTest {
-        val requestedSchema = ElicitRequestParams.RequestedSchema(
-            properties = mapOf("name" to StringSchema()),
-            required = listOf("name"),
-        )
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Decline)
-        }
-
-        val result = serverSession.createElicitation(message = "decline", requestedSchema = requestedSchema)
-
-        assertEquals(ElicitResult.Action.Decline, result.action)
-        assertNull(result.content)
-
-        client.close()
-    }
-
-    @Test
-    fun `should pass through cancelled elicitation without validation`() = runTest {
-        val requestedSchema = ElicitRequestParams.RequestedSchema(
-            properties = mapOf("name" to StringSchema()),
-            required = listOf("name"),
-        )
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Cancel)
-        }
-
-        val result = serverSession.createElicitation(message = "cancel", requestedSchema = requestedSchema)
-
-        assertEquals(ElicitResult.Action.Cancel, result.action)
-        assertNull(result.content)
-
-        client.close()
-    }
-
    @Test
    fun `should apply elicitation defaults for missing fields in empty content`() = runTest {
        val schema = defaultsTestSchema()
@ -1354,189 +1251,6 @@ class ClientTest {
        client.close()
    }

-    // ── URL-mode elicitation (SEP-1036) ─────────────────────────────────
-
-    @Test
-    fun `should handle URL mode elicitation end-to-end`() = runTest {
-        val client = Client(
-            Implementation(name = "test client", version = "1.0"),
-            ClientOptions(
-                capabilities = ClientCapabilities(
-                    elicitation = ClientCapabilities.Elicitation(url = EmptyJsonObject),
-                ),
-            ),
-        )
-
-        val elicitationId = "550e8400-e29b-41d4-a716-446655440000"
-        val url = "https://oauth.example.com/authorize"
-
-        client.setElicitationHandler { request ->
-            val params = assertIs<ElicitRequestURLParams>(request.params)
-            assertEquals(elicitationId, params.elicitationId)
-            assertEquals(url, params.url)
-            ElicitResult(action = ElicitResult.Action.Accept)
-        }
-
-        val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
-        val server = Server(
-            serverInfo = Implementation(name = "test server", version = "1.0"),
-            options = ServerOptions(capabilities = ServerCapabilities()),
-        )
-
-        val serverSessionResult = CompletableDeferred<ServerSession>()
-        listOf(
-            launch { client.connect(clientTransport) },
-            launch { serverSessionResult.complete(server.createSession(serverTransport)) },
-        ).joinAll()
-        val serverSession = serverSessionResult.await()
-
-        val result = serverSession.createElicitation(
-            message = "Authorize access to continue",
-            elicitationId = elicitationId,
-            url = url,
-        )
-
-        assertEquals(ElicitResult.Action.Accept, result.action)
-        assertNull(result.content)
-
-        client.close()
-    }
-
-    @Test
-    fun `should reject URL mode elicitation when client supports only form mode`() = runTest {
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Accept)
-        }
-
-        val exception = assertFailsWith<IllegalArgumentException> {
-            serverSession.createElicitation(
-                message = "Authorize",
-                elicitationId = "id-1",
-                url = "https://example.com/auth",
-            )
-        }
-        assertTrue(exception.message!!.contains("elicitation.url"))
-
-        client.close()
-    }
-
-    @Test
-    fun `should deliver elicitation complete notification to client`() = runTest {
-        val received = CompletableDeferred<ElicitationCompleteNotification>()
-        val client = Client(
-            Implementation(name = "test client", version = "1.0"),
-            ClientOptions(
-                capabilities = ClientCapabilities(
-                    elicitation = ClientCapabilities.Elicitation(url = EmptyJsonObject),
-                ),
-            ),
-        )
-        client.setElicitationCompleteHandler { received.complete(it) }
-
-        val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
-        val server = Server(
-            serverInfo = Implementation(name = "test server", version = "1.0"),
-            options = ServerOptions(capabilities = ServerCapabilities()),
-        )
-
-        val serverSessionResult = CompletableDeferred<ServerSession>()
-        listOf(
-            launch { client.connect(clientTransport) },
-            launch { serverSessionResult.complete(server.createSession(serverTransport)) },
-        ).joinAll()
-        val serverSession = serverSessionResult.await()
-
-        val elicitationId = "complete-id-1"
-        serverSession.sendElicitationComplete(
-            ElicitationCompleteNotification(ElicitationCompleteNotificationParams(elicitationId = elicitationId)),
-        )
-
-        val notification = received.await()
-        assertEquals(elicitationId, notification.params.elicitationId)
-
-        client.close()
-    }
-
-    @Test
-    fun `should reject elicitation complete when client supports only form mode`() = runTest {
-        val (client, serverSession) = setupElicitationPair {
-            ElicitResult(action = ElicitResult.Action.Accept)
-        }
-
-        val exception = assertFailsWith<IllegalArgumentException> {
-            serverSession.sendElicitationComplete(
-                ElicitationCompleteNotification(ElicitationCompleteNotificationParams(elicitationId = "id-1")),
-            )
-        }
-        assertTrue(exception.message!!.contains("elicitation.url"))
-
-        client.close()
-    }
-
-    @Test
-    fun `setElicitationCompleteHandler should require url capability`() = runTest {
-        val client = Client(
-            Implementation(name = "test client", version = "1.0"),
-            ClientOptions(
-                capabilities = ClientCapabilities(
-                    elicitation = ClientCapabilities.Elicitation(),
-                ),
-            ),
-        )
-
-        assertFailsWith<IllegalStateException> {
-            client.setElicitationCompleteHandler { }
-        }
-    }
-
-    @Test
-    fun `should surface URL elicitation required error to client as typed exception`() = runTest {
-        val client = Client(
-            Implementation(name = "test client", version = "1.0"),
-            ClientOptions(
-                capabilities = ClientCapabilities(
-                    elicitation = ClientCapabilities.Elicitation(url = EmptyJsonObject),
-                ),
-            ),
-        )
-
-        val elicitationId = "auth-required-1"
-        val url = "https://oauth.example.com/authorize"
-
-        val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
-        val server = Server(
-            serverInfo = Implementation(name = "test server", version = "1.0"),
-            options = ServerOptions(capabilities = ServerCapabilities(tools = ServerCapabilities.Tools(true))),
-        )
-        server.addTool("needs-auth", "Requires URL elicitation") {
-            throw UrlElicitationRequiredException(
-                listOf(
-                    ElicitRequestURLParams(
-                        message = "Authorize to continue",
-                        elicitationId = elicitationId,
-                        url = url,
-                    ),
-                ),
-            )
-        }
-
-        val serverSessionResult = CompletableDeferred<ServerSession>()
-        listOf(
-            launch { client.connect(clientTransport) },
-            launch { serverSessionResult.complete(server.createSession(serverTransport)) },
-        ).joinAll()
-        serverSessionResult.await()
-
-        val exception = assertFailsWith<UrlElicitationRequiredException> {
-            client.callTool(name = "needs-auth", arguments = emptyMap())
-        }
-        val elicitation = exception.elicitations.single()
-        assertEquals(elicitationId, elicitation.elicitationId)
-        assertEquals(url, elicitation.url)
-
-        client.close()
-    }
-
    private fun defaultsTestSchema(): ElicitRequestParams.RequestedSchema = ElicitRequestParams.RequestedSchema(
        properties = mapOf(
            "name" to StringSchema(description = "User name", default = "John Doe"),
--- a/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/StdioClientTransportTest.kt
+++ b/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/client/StdioClientTransportTest.kt
@ -7,13 +7,9 @@ import io.modelcontextprotocol.kotlin.sdk.types.McpException
 import io.modelcontextprotocol.kotlin.test.utils.createSleepyProcessBuilder
 import io.modelcontextprotocol.kotlin.test.utils.createTeeProcessBuilder
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.async
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.withTimeout
-import kotlinx.coroutines.withTimeoutOrNull
-import kotlinx.io.Buffer
-import kotlinx.io.RawSource
 import kotlinx.io.asSink
 import kotlinx.io.asSource
 import kotlinx.io.buffered
@ -22,12 +18,10 @@ import org.junit.jupiter.api.Timeout
 import org.junit.jupiter.api.assertThrows
 import org.junit.jupiter.api.condition.DisabledOnOs
 import org.junit.jupiter.api.condition.OS
-import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
 import kotlin.concurrent.atomics.AtomicBoolean
 import kotlin.concurrent.atomics.ExperimentalAtomicApi
 import kotlin.test.assertFalse
-import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 import kotlin.test.fail
 import kotlin.time.Duration.Companion.seconds
@ -115,43 +109,6 @@ class StdioClientTransportTest : BaseTransportTest() {
        }
    }

-    @OptIn(ExperimentalAtomicApi::class)
-    @Test
-    fun `should close cleanly while stdin read is blocked`(): Unit = runBlocking(Dispatchers.IO) {
-        val input = BlockingRawSource()
-
-        val transport = StdioClientTransport(
-            input = input.buffered(),
-            output = Buffer(),
-        )
-
-        val didClose = AtomicBoolean(false)
-        transport.onClose { didClose.store(true) }
-        transport.onError { error ->
-            fail("Unexpected error while closing transport: $error")
-        }
-
-        transport.start()
-
-        eventually(2.seconds) {
-            assertTrue(input.readStarted, "Transport should start reading stdin before close")
-        }
-
-        val closeJob = async {
-            transport.close()
-        }
-
-        val closed = withTimeoutOrNull(1.seconds) {
-            closeJob.await()
-        }
-
-        input.close()
-        closeJob.await()
-
-        assertNotNull(closed, "Transport.close() should not wait for stdin to produce data or EOF")
-        assertTrue(didClose.load(), "Transport should be closed after close() call")
-    }
-
    @Test
    fun `should read messages`() = runTest {
        val processBuilder = createTeeProcessBuilder()
@ -190,22 +147,4 @@ class StdioClientTransportTest : BaseTransportTest() {
        process.waitFor()
        process.destroyForcibly()
    }
-
-    private class BlockingRawSource : RawSource {
-        private val closed = CountDownLatch(1)
-
-        @Volatile
-        var readStarted: Boolean = false
-            private set
-
-        override fun readAtMostTo(sink: Buffer, byteCount: Long): Long {
-            readStarted = true
-            closed.await()
-            return -1L
-        }
-
-        override fun close() {
-            closed.countDown()
-        }
-    }
 }
--- a/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/ProtocolConcurrencyIntegrationTest.kt
+++ b/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/ProtocolConcurrencyIntegrationTest.kt
@ -1,306 +0,0 @@
-package io.modelcontextprotocol.kotlin.sdk.integration
-
-import io.kotest.matchers.shouldBe
-import io.modelcontextprotocol.kotlin.sdk.ExperimentalMcpApi
-import io.modelcontextprotocol.kotlin.sdk.client.Client
-import io.modelcontextprotocol.kotlin.sdk.client.ClientOptions
-import io.modelcontextprotocol.kotlin.sdk.server.Server
-import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
-import io.modelcontextprotocol.kotlin.sdk.server.ServerSession
-import io.modelcontextprotocol.kotlin.sdk.shared.InMemoryTransport
-import io.modelcontextprotocol.kotlin.sdk.shared.currentRequestHandlerExtra
-import io.modelcontextprotocol.kotlin.sdk.testing.ChannelTransport
-import io.modelcontextprotocol.kotlin.sdk.types.CallToolRequest
-import io.modelcontextprotocol.kotlin.sdk.types.CallToolRequestParams
-import io.modelcontextprotocol.kotlin.sdk.types.CallToolResult
-import io.modelcontextprotocol.kotlin.sdk.types.ClientCapabilities
-import io.modelcontextprotocol.kotlin.sdk.types.CreateMessageRequest
-import io.modelcontextprotocol.kotlin.sdk.types.CreateMessageRequestParams
-import io.modelcontextprotocol.kotlin.sdk.types.CreateMessageResult
-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.InitializedNotification
-import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCError
-import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCMessage
-import io.modelcontextprotocol.kotlin.sdk.types.JSONRPCResponse
-import io.modelcontextprotocol.kotlin.sdk.types.LATEST_PROTOCOL_VERSION
-import io.modelcontextprotocol.kotlin.sdk.types.ListRootsRequest
-import io.modelcontextprotocol.kotlin.sdk.types.ListRootsResult
-import io.modelcontextprotocol.kotlin.sdk.types.ListToolsRequest
-import io.modelcontextprotocol.kotlin.sdk.types.ListToolsResult
-import io.modelcontextprotocol.kotlin.sdk.types.Method
-import io.modelcontextprotocol.kotlin.sdk.types.RequestId
-import io.modelcontextprotocol.kotlin.sdk.types.Role
-import io.modelcontextprotocol.kotlin.sdk.types.SamplingMessage
-import io.modelcontextprotocol.kotlin.sdk.types.ServerCapabilities
-import io.modelcontextprotocol.kotlin.sdk.types.TextContent
-import io.modelcontextprotocol.kotlin.sdk.types.toJSON
-import kotlinx.coroutines.CompletableDeferred
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.runBlocking
-import kotlinx.coroutines.withTimeout
-import java.util.concurrent.ConcurrentHashMap
-import java.util.concurrent.CopyOnWriteArrayList
-import java.util.concurrent.atomic.AtomicReference
-import kotlin.coroutines.cancellation.CancellationException
-import kotlin.test.Test
-import kotlin.test.assertEquals
-import kotlin.test.assertFalse
-import kotlin.time.Duration.Companion.seconds
-
-/**
- * End-to-end tests for concurrent inbound dispatch enabled after the MCP handshake.
- *
- * Handlers run on a real [kotlinx.coroutines.Dispatchers.Default], so these use [runBlocking] with
- * explicit [withTimeout] guards. A virtual test clock would false-fire timeouts against cross-thread
- * real dispatchers.
- */
-@OptIn(ExperimentalMcpApi::class)
-class ProtocolConcurrencyIntegrationTest {
-
-    private fun rootsClient(): Client = Client(
-        clientInfo = Implementation(name = "test client", version = "1.0"),
-        options = ClientOptions(
-            capabilities = ClientCapabilities(roots = ClientCapabilities.Roots(listChanged = null)),
-        ),
-    )
-
-    private fun toolsServer(): Server = Server(
-        serverInfo = Implementation(name = "test server", version = "1.0"),
-        options = ServerOptions(
-            capabilities = ServerCapabilities(tools = ServerCapabilities.Tools(listChanged = null)),
-        ),
-    )
-
-    // ChannelTransport delivers inbound messages as soon as its read loop starts, which is before
-    // start() marks it operational. Creating the session first keeps the client's initialize from
-    // landing on a transport that would reject the session's response.
-    private suspend fun connect(
-        client: Client,
-        clientTransport: ChannelTransport,
-        server: Server,
-        serverTransport: ChannelTransport,
-    ): ServerSession {
-        val serverSession = server.createSession(serverTransport)
-        client.connect(clientTransport)
-        return serverSession
-    }
-
-    // The motivating deadlock over real serial read loops: a server tool handler makes a
-    // server-to-client request (roots/list) while still handling the client's tools/call.
-    @Test
-    fun `server tool handler can call roots list mid-handling without deadlock`() = runBlocking {
-        val client = rootsClient()
-        val server = toolsServer()
-        val (clientTransport, serverTransport) = ChannelTransport.createLinkedPair()
-
-        val serverSession = connect(client, clientTransport, server, serverTransport)
-
-        // Register the tools/call handler directly on the session so it can call back to the client
-        // mid-handling. Before concurrent dispatch this would deadlock: the server read loop is
-        // blocked by the tool handler and can never deliver the roots/list response.
-        serverSession.setRequestHandler<CallToolRequest>(Method.Defined.ToolsCall) { _, _ ->
-            val roots = serverSession.request<ListRootsResult>(ListRootsRequest())
-            CallToolResult(content = listOf(TextContent(text = "roots=${roots.roots.size}")))
-        }
-
-        val result = withTimeout(10.seconds) {
-            client.callTool(CallToolRequest(CallToolRequestParams("needs-roots")))
-        }
-        val text = (result as CallToolResult).content.filterIsInstance<TextContent>().single().text
-        text shouldBe "roots=0"
-
-        client.close()
-        server.close()
-    }
-
-    // Client-side mirror: a client sampling handler makes a client-to-server request (tools/list)
-    // while still handling the server's sampling/createMessage.
-    @Test
-    fun `client sampling handler can call the server mid-handling without deadlock`() = runBlocking {
-        val client = Client(
-            clientInfo = Implementation(name = "test client", version = "1.0"),
-            options = ClientOptions(
-                capabilities = ClientCapabilities(sampling = ClientCapabilities.Sampling()),
-            ),
-        )
-        val server = toolsServer()
-        val (clientTransport, serverTransport) = ChannelTransport.createLinkedPair()
-
-        client.setRequestHandler<CreateMessageRequest>(Method.Defined.SamplingCreateMessage) { _, _ ->
-            val tools = client.request<ListToolsResult>(ListToolsRequest())
-            CreateMessageResult(
-                role = Role.Assistant,
-                content = TextContent(text = "tools=${tools.tools.size}"),
-                model = "test-model",
-            )
-        }
-
-        val serverSession = connect(client, clientTransport, server, serverTransport)
-
-        val result = withTimeout(10.seconds) {
-            serverSession.request<CreateMessageResult>(
-                CreateMessageRequest(
-                    CreateMessageRequestParams(
-                        maxTokens = 100,
-                        messages = listOf(SamplingMessage(role = Role.User, content = TextContent(text = "hi"))),
-                    ),
-                ),
-            )
-        }
-        val text = result.content.filterIsInstance<TextContent>().single().text
-        text shouldBe "tools=0"
-
-        client.close()
-        server.close()
-    }
-
-    // Nested-cancel cascade: cancelling the client's tools/call must reach the server tool handler
-    // over the wire and cascade into its nested roots/list request, cancelling the parked
-    // client-side roots handler. No tools/call response is ever sent.
-    @Test
-    fun `cancelling a tool call cascades into its nested roots list request`() = runBlocking {
-        val client = rootsClient()
-        val server = toolsServer()
-        val (clientTransport, serverTransport) = ChannelTransport.createLinkedPair()
-
-        val capturedToolCallId = AtomicReference<RequestId?>(null)
-        val toolHandlerCancelled = CompletableDeferred<CancellationException>()
-        val rootsHandlerEntered = CompletableDeferred<Unit>()
-        val rootsHandlerCancelled = CompletableDeferred<CancellationException>()
-        val parkForever = CompletableDeferred<ListRootsResult>()
-        val unexpectedToolCallResponse = CompletableDeferred<Unit>()
-
-        // Tap the server->client direction (client transport inbound) to prove no tools/call
-        // response is ever delivered once the call is cancelled.
-        clientTransport.onMessage { message ->
-            if (message is JSONRPCResponse && message.id == capturedToolCallId.get()) {
-                unexpectedToolCallResponse.complete(Unit)
-            }
-        }
-
-        val serverSession = connect(client, clientTransport, server, serverTransport)
-
-        // Client roots handler parks until cancelled and records the cancellation.
-        client.setRequestHandler<ListRootsRequest>(Method.Defined.RootsList) { _, _ ->
-            rootsHandlerEntered.complete(Unit)
-            try {
-                parkForever.await()
-            } catch (e: CancellationException) {
-                rootsHandlerCancelled.complete(e)
-                throw e
-            }
-        }
-
-        // Tool handler makes a nested server->client request and records its own cancellation.
-        serverSession.setRequestHandler<CallToolRequest>(Method.Defined.ToolsCall) { _, _ ->
-            val extra = currentRequestHandlerExtra()!!
-            capturedToolCallId.set(extra.requestId)
-            try {
-                extra.sendRequest<ListRootsResult>(ListRootsRequest())
-            } catch (e: CancellationException) {
-                toolHandlerCancelled.complete(e)
-                throw e
-            }
-            CallToolResult(content = listOf(TextContent(text = "unreachable")))
-        }
-
-        val call = launch { client.callTool(CallToolRequest(CallToolRequestParams("nested"))) }
-
-        withTimeout(10.seconds) { rootsHandlerEntered.await() }
-        call.cancel(CancellationException("user aborted"))
-
-        withTimeout(10.seconds) { toolHandlerCancelled.await() }
-        withTimeout(10.seconds) { rootsHandlerCancelled.await() }
-
-        // The server suppresses the response for a cancelled request, so none is ever sent.
-        assertFalse(
-            unexpectedToolCallResponse.isCompleted,
-            "no tools/call response should be delivered after the call was cancelled",
-        )
-
-        client.close()
-        server.close()
-    }
-
-    // Init gate plus context element in a high-level handler: initialize and tools/list are
-    // pipelined before notifications/initialized and answered serially in order. After the
-    // handshake a high-level addTool handler can observe currentRequestHandlerExtra().
-    @Test
-    fun `pipelined initialize and tools list are processed serially then context element is available`(): Unit =
-        runBlocking {
-            val server = toolsServer()
-            server.addTool(name = "ctx-tool", description = "returns its request id") {
-                val extra = currentRequestHandlerExtra()
-                checkNotNull(extra) { "currentRequestHandlerExtra() must be non-null inside a tool handler" }
-                CallToolResult(content = listOf(TextContent(text = extra.requestId.asText())))
-            }
-
-            val (clientTransport, serverTransport) = InMemoryTransport.createLinkedPair()
-
-            val arrivalOrder = CopyOnWriteArrayList<RequestId>()
-            val pending = ConcurrentHashMap<RequestId, CompletableDeferred<JSONRPCMessage>>()
-            clientTransport.onMessage { message ->
-                val id = when (message) {
-                    is JSONRPCResponse -> message.id
-                    is JSONRPCError -> message.id
-                    else -> null
-                }
-                if (id != null) {
-                    arrivalOrder.add(id)
-                    pending[id]?.complete(message)
-                }
-            }
-
-            // Drive the client side manually over the raw transport.
-            server.createSession(serverTransport)
-
-            val initRequest = InitializeRequest(
-                InitializeRequestParams(
-                    protocolVersion = LATEST_PROTOCOL_VERSION,
-                    capabilities = ClientCapabilities(),
-                    clientInfo = Implementation(name = "raw-client", version = "1.0"),
-                ),
-            ).toJSON()
-            val toolsListRequest = ListToolsRequest().toJSON()
-
-            val initAnswered = pending.expect(initRequest.id)
-            val toolsListAnswered = pending.expect(toolsListRequest.id)
-
-            // Pipelined before notifications/initialized: both handled in the serial dispatch phase.
-            clientTransport.send(initRequest)
-            clientTransport.send(toolsListRequest)
-
-            withTimeout(10.seconds) { initAnswered.await() }
-            withTimeout(10.seconds) { toolsListAnswered.await() }
-
-            // Deterministic serial ordering: initialize answered before tools/list.
-            assertEquals(
-                listOf(initRequest.id, toolsListRequest.id),
-                arrivalOrder.toList(),
-                "pipelined requests must be answered in arrival order",
-            )
-
-            // Complete the handshake, then call the high-level tool.
-            clientTransport.send(InitializedNotification().toJSON())
-
-            val toolCallRequest = CallToolRequest(CallToolRequestParams("ctx-tool")).toJSON()
-            val toolCallAnswered = pending.expect(toolCallRequest.id)
-            clientTransport.send(toolCallRequest)
-
-            val toolCallResponse = withTimeout(10.seconds) { toolCallAnswered.await() } as JSONRPCResponse
-            val text = (toolCallResponse.result as CallToolResult).content.filterIsInstance<TextContent>().single().text
-            // The handler echoed its request id, proving currentRequestHandlerExtra() was available.
-            text shouldBe toolCallRequest.id.asText()
-        }
-
-    private fun ConcurrentHashMap<RequestId, CompletableDeferred<JSONRPCMessage>>.expect(
-        id: RequestId,
-    ): CompletableDeferred<JSONRPCMessage> = CompletableDeferred<JSONRPCMessage>().also { put(id, it) }
-
-    private fun RequestId.asText(): String = when (this) {
-        is RequestId.StringId -> value
-        is RequestId.NumberId -> value.toString()
-    }
-}
--- a/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/kotlin/AbstractPromptIntegrationTest.kt
+++ b/integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/kotlin/AbstractPromptIntegrationTest.kt
@ -698,8 +698,8 @@ abstract class AbstractPromptIntegrationTest : KotlinTestBase() {

        val expectedMessage = "Prompt not found: non-existent-prompt"

-        withClue("Exception code should be INVALID_PARAMS: ${RPCError.ErrorCode.INVALID_PARAMS}") {
-            exception.code shouldBe RPCError.ErrorCode.INVALID_PARAMS
+        withClue("Exception code should be INTERNAL_ERROR: -32603") {
+            exception.code shouldBe -32603
        }
        withClue("Unexpected error message for non-existent prompt") {
            exception.message shouldBe expectedMessage
--- a/Show more
+++ b/Show more