refactor: Harden detekt setup, address some issues (#507)

# Detekt setup hardeing; address some issues

- Address some detekt findings: missing KDocs, formatting, use `check*`
& `orEmpty()``
- Remove unnecessary KDoc comments from deprecated classes in `types.kt`
- Add Detekt baseline XML files for all modules
- Enforce stricter Detekt rules by setting `failOnSeverity` from `None`
to `Error`

## Motivation and Context

Detekt is not actually failing the build on violations. This PR is
enabling Detekt to fail on errors. Baseline fines added for historical
issues. Follow-up for #501

## How Has This Been Tested?
Regressions

## Breaking Changes

No breaking changes.

## 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)
- [ ] Refactoring
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] 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
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

integration-test/detekt-baseline-commonTestSourceSet.xml

@@ -0,0 +1,11 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<SmellBaseline>
+  <ManuallySuppressedIssues/>
+  <CurrentIssues>
+    <ID>EmptyFunctionBlock:ClientTest.kt:ClientTest.&lt;no name provided>${ }</ID>
+    <ID>EmptyFunctionBlock:ClientTest.kt:ClientTest.&lt;no name provided>${}</ID>
+    <ID>LargeClass:ClientTest.kt:ClientTest</ID>
+    <ID>LongMethod:ClientTest.kt:ClientTest$@Test fun `JSONRPCRequest with ToolsList method and default params returns list of tools`</ID>
+    <ID>LongMethod:ClientTest.kt:ClientTest$@Test fun `should handle logging setLevel request`</ID>
+  </CurrentIssues>
+</SmellBaseline>

integration-test/detekt-baseline-test.xml

@@ -0,0 +1,47 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<SmellBaseline>
+  <ManuallySuppressedIssues/>
+  <CurrentIssues>
+    <ID>AbstractClassCanBeConcreteClass:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$AbstractPromptIntegrationTest</ID>
+    <ID>AbstractClassCanBeConcreteClass:AbstractResourceIntegrationTest.kt:AbstractResourceIntegrationTest$AbstractResourceIntegrationTest</ID>
+    <ID>AbstractClassCanBeConcreteClass:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest$AbstractToolIntegrationTest</ID>
+    <ID>AbstractClassCanBeConcreteClass:BaseTransportTest.kt:BaseTransportTest$BaseTransportTest</ID>
+    <ID>CyclomaticComplexMethod:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest$private fun setupCalculatorTool</ID>
+    <ID>EmptyFunctionBlock:ClientTest.kt:ClientTest.&lt;no name provided>${ }</ID>
+    <ID>EmptyFunctionBlock:ClientTest.kt:ClientTest.&lt;no name provided>${}</ID>
+    <ID>ForbiddenComment:StdioClientTransportTest.kt:StdioClientTransportTest$// TODO: fix running on windows</ID>
+    <ID>InjectDispatcher:AbstractKotlinClientTsServerTest.kt:AbstractKotlinClientTsServerTest$IO</ID>
+    <ID>InjectDispatcher:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$IO</ID>
+    <ID>InjectDispatcher:AbstractResourceIntegrationTest.kt:AbstractResourceIntegrationTest$IO</ID>
+    <ID>InjectDispatcher:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest$IO</ID>
+    <ID>InjectDispatcher:KotlinClientTsServerEdgeCasesTestSse.kt:KotlinClientTsServerEdgeCasesTestSse$IO</ID>
+    <ID>InjectDispatcher:KotlinClientTsServerEdgeCasesTestStdio.kt:KotlinClientTsServerEdgeCasesTestStdio$IO</ID>
+    <ID>InjectDispatcher:SseIntegrationTest.kt:SseIntegrationTest$IO</ID>
+    <ID>InjectDispatcher:StdioClientTransportTest.kt:StdioClientTransportTest$IO</ID>
+    <ID>InjectDispatcher:StreamableHttpIntegrationTest.kt:StreamableHttpIntegrationTest$IO</ID>
+    <ID>InjectDispatcher:TsEdgeCasesTestSse.kt:TsEdgeCasesTestSse$IO</ID>
+    <ID>InjectDispatcher:WebSocketIntegrationTest.kt:WebSocketIntegrationTest$IO</ID>
+    <ID>LargeClass:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest : KotlinTestBase</ID>
+    <ID>LargeClass:ClientTest.kt:ClientTest</ID>
+    <ID>LongMethod:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$@Test fun testMissingRequiredArguments</ID>
+    <ID>LongMethod:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$override fun configureServer</ID>
+    <ID>LongMethod:AbstractResourceIntegrationTest.kt:AbstractResourceIntegrationTest$override fun configureServer</ID>
+    <ID>LongMethod:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest$private fun setupCalculatorTool</ID>
+    <ID>LongMethod:ClientTest.kt:ClientTest$@Test fun `JSONRPCRequest with ToolsList method and default params returns list of tools`</ID>
+    <ID>LongMethod:ClientTest.kt:ClientTest$@Test fun `should handle logging setLevel request`</ID>
+    <ID>LongMethod:KotlinServerForTsClientSse.kt:HttpServerTransport$suspend fun handleRequest</ID>
+    <ID>LongMethod:KotlinServerForTsClientSse.kt:KotlinServerForTsClient$fun createMcpServer: Server</ID>
+    <ID>LongMethod:KotlinServerForTsClientSse.kt:KotlinServerForTsClient$fun start</ID>
+    <ID>LongMethod:KotlinTestBase.kt:KotlinTestBase$protected fun setupServer</ID>
+    <ID>LongMethod:ServerResourcesNotificationSubscribeTest.kt:ServerResourcesNotificationSubscribeTest$@Test fun `should send resource notifications`</ID>
+    <ID>LongMethod:TsEdgeCasesTestSse.kt:TsEdgeCasesTestSse$@Test @Timeout(30, unit = TimeUnit.SECONDS) fun testComplexConcurrentRequests: Unit</ID>
+    <ID>MatchingDeclarationName:PromptIntegrationTestSse.kt:SchemaPromptIntegrationTestSse : AbstractPromptIntegrationTest</ID>
+    <ID>SleepInsteadOfDelay:KotlinServerForTsClientSse.kt:KotlinServerForTsClient$sleep(500)</ID>
+    <ID>ThrowsCount:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$override fun configureServer</ID>
+    <ID>UnusedPrivateProperty:KotlinClientTsServerTestSse.kt:KotlinClientTsServerTestSse$private val host = "localhost"</ID>
+    <ID>UseCheckOrError:ClientTest.kt:ClientTest.&lt;no name provided>$throw IllegalStateException("Test error")</ID>
+    <ID>UseOrEmpty:AbstractToolIntegrationTest.kt:AbstractToolIntegrationTest$(request.params.arguments?.get("tags") as? JsonArray)?.mapNotNull { (it as? JsonPrimitive)?.content } ?: emptyList()</ID>
+    <ID>UseRequire:AbstractPromptIntegrationTest.kt:AbstractPromptIntegrationTest$throw IllegalArgumentException("Missing required argument: $argName")</ID>
+    <ID>VarCouldBeVal:KotlinClientTsServerEdgeCasesTestSse.kt:KotlinClientTsServerEdgeCasesTestSse$private lateinit var client: Client</ID>
+  </CurrentIssues>
+</SmellBaseline>

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

@@ -40,7 +40,7 @@ class InMemoryTransport : AbstractTransport() {
     }
 
     override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
-        val other = otherTransport ?: throw IllegalStateException("Not connected")
+        val other = checkNotNull(otherTransport) { "Not connected" }
 
         other._onMessage.invoke(message)
     }

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

@@ -266,7 +266,7 @@ abstract class AbstractPromptIntegrationTest : KotlinTestBase() {
                 ),
             ),
         ) { request ->
-            val args = request.params.arguments ?: emptyMap()
+            val args = request.params.arguments.orEmpty()
             val arg1 = args["requiredArg1"] ?: throw IllegalArgumentException(
                 "Missing required argument: requiredArg1",
             )

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

@@ -24,8 +24,10 @@ class ServerPromptsNotificationTest : AbstractServerFeaturesTest() {
     fun `addPrompt should send notification`() = runTest {
         // Configure notification handler
         val notifications = mutableListOf<PromptListChangedNotification>()
-        client.setNotificationHandler<PromptListChangedNotification>(Method.Defined.NotificationsPromptsListChanged) {
-            notifications.add(it)
+        client.setNotificationHandler<PromptListChangedNotification>(
+            Method.Defined.NotificationsPromptsListChanged,
+        ) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }
 
@@ -96,8 +98,10 @@ class ServerPromptsNotificationTest : AbstractServerFeaturesTest() {
     fun `notification should not be send when removed prompt does not exists`() = runTest {
         // Track notifications
         val notifications = mutableListOf<PromptListChangedNotification>()
-        client.setNotificationHandler<PromptListChangedNotification>(Method.Defined.NotificationsPromptsListChanged) {
-            notifications.add(it)
+        client.setNotificationHandler<PromptListChangedNotification>(
+            Method.Defined.NotificationsPromptsListChanged,
+        ) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }
 

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

@@ -34,7 +34,7 @@ class ServerPromptsTest : AbstractServerFeaturesTest() {
         server.addPrompt(testPrompt) {
             GetPromptResult(
                 description = "Test prompt description",
-                messages = listOf(),
+                messages = emptyList(),
             )
         }
 
@@ -70,13 +70,13 @@ class ServerPromptsTest : AbstractServerFeaturesTest() {
         server.addPrompt(testPrompt1) {
             GetPromptResult(
                 description = "Test prompt description 1",
-                messages = listOf(),
+                messages = emptyList(),
             )
         }
         server.addPrompt(testPrompt2) {
             GetPromptResult(
                 description = "Test prompt description 2",
-                messages = listOf(),
+                messages = emptyList(),
             )
         }
 

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

@@ -50,12 +50,12 @@ class ServerResourcesNotificationSubscribeTest : AbstractServerFeaturesTest() {
             name = "Test Resource 1",
             description = "A test resource 1",
             mimeType = "text/plain",
-        ) {
+        ) { request ->
             ReadResourceResult(
                 contents = listOf(
                     TextResourceContents(
                         text = "Test resource content 1",
-                        uri = it.uri,
+                        uri = request.uri,
                         mimeType = "text/plain",
                     ),
                 ),
@@ -67,12 +67,12 @@ class ServerResourcesNotificationSubscribeTest : AbstractServerFeaturesTest() {
             name = "Test Resource 2",
             description = "A test resource 2",
             mimeType = "text/plain",
-        ) {
+        ) { request ->
             ReadResourceResult(
                 contents = listOf(
                     TextResourceContents(
                         text = "Test resource content 2",
-                        uri = it.uri,
+                        uri = request.uri,
                         mimeType = "text/plain",
                     ),
                 ),
@@ -121,8 +121,8 @@ class ServerResourcesNotificationSubscribeTest : AbstractServerFeaturesTest() {
         println("Thread ${Thread.currentThread().name} test 1")
         // Track notifications
         val notifications = ConcurrentLinkedQueue<ResourceUpdatedNotification>()
-        client.setNotificationHandler<ResourceUpdatedNotification>(NotificationsResourcesUpdated) {
-            notifications.add(it)
+        client.setNotificationHandler<ResourceUpdatedNotification>(NotificationsResourcesUpdated) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }
 

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

@@ -26,8 +26,8 @@ class ServerResourcesNotificationTest : AbstractServerFeaturesTest() {
         val notifications = mutableListOf<ResourceListChangedNotification>()
         client.setNotificationHandler<ResourceListChangedNotification>(
             Method.Defined.NotificationsResourcesListChanged,
-        ) {
-            notifications.add(it)
+        ) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }
 

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

@@ -51,8 +51,10 @@ class ServerToolsNotificationTest : AbstractServerFeaturesTest() {
     fun `removeTools should remove multiple tools and send two notifications`() = runTest {
         // Configure notification handler
         val notifications = mutableListOf<ToolListChangedNotification>()
-        client.setNotificationHandler<ToolListChangedNotification>(Method.Defined.NotificationsToolsListChanged) {
-            notifications.add(it)
+        client.setNotificationHandler<ToolListChangedNotification>(
+            Method.Defined.NotificationsToolsListChanged,
+        ) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }
 
@@ -83,8 +85,10 @@ class ServerToolsNotificationTest : AbstractServerFeaturesTest() {
     fun `notification should not be send when removed tool does not exists`() = runTest {
         // Track notifications
         val notifications = mutableListOf<ToolListChangedNotification>()
-        client.setNotificationHandler<ToolListChangedNotification>(Method.Defined.NotificationsToolsListChanged) {
-            notifications.add(it)
+        client.setNotificationHandler<ToolListChangedNotification>(
+            Method.Defined.NotificationsToolsListChanged,
+        ) { notification ->
+            notifications.add(notification)
             CompletableDeferred(Unit)
         }