chore(build): integrate Detekt for static code analysis

.github/workflows/codeql.yml

@@ -71,6 +71,7 @@ jobs:
             :kotlin-sdk:compileKotlinJvm \
             :integration-test:compileKotlinJvm \
             :conformance-test:testClasses \
+            detekt \
             -Pkotlin.incremental=false \
             --no-daemon --stacktrace --rerun-tasks
 

build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
     id("mcp.dokka")
+    alias(libs.plugins.detekt)
     alias(libs.plugins.ktlint)
     alias(libs.plugins.kover)
 }
@@ -18,6 +19,13 @@ dependencies {
 subprojects {
     apply(plugin = "org.jlleitschuh.gradle.ktlint")
     apply(plugin = "org.jetbrains.kotlinx.kover")
+    apply(plugin = "dev.detekt")
+
+    detekt {
+        config = files("$rootDir/detekt.yml")
+        buildUponDefaultConfig = true
+        ignoreFailures = false // to fix issues and enable
+    }
 }
 
 dokka {

buildSrc/src/main/kotlin/mcp.multiplatform.gradle.kts

@@ -61,3 +61,7 @@ kotlin {
     explicitApi = ExplicitApiMode.Strict
     jvmToolchain(21)
 }
+
+tasks.named("detekt").configure {
+    dependsOn("detektMainJvm", "detektTestJvm")
+}

conformance-test/src/test/kotlin/io/modelcontextprotocol/kotlin/sdk/conformance/ConformanceServer.kt

@@ -73,6 +73,7 @@ private const val MESSAGE_QUEUE_CAPACITY = 256
 private fun isInitializeRequest(json: JsonElement): Boolean =
     json is JsonObject && json["method"]?.jsonPrimitive?.contentOrNull == "initialize"
 
+@Suppress("CyclomaticComplexMethod", "LongMethod")
 fun main(args: Array<String>) {
     val port = args.getOrNull(0)?.toIntOrNull() ?: 3000
 
@@ -236,6 +237,7 @@ fun main(args: Array<String>) {
     }.start(wait = true)
 }
 
+@Suppress("LongMethod")
 private fun createConformanceServer(): Server {
     val server = Server(
         Implementation(

conformance-test/src/test/kotlin/io/modelcontextprotocol/kotlin/sdk/conformance/ConformanceTest.kt

@@ -7,6 +7,7 @@ import org.junit.jupiter.api.BeforeAll
 import org.junit.jupiter.api.DynamicTest
 import org.junit.jupiter.api.TestFactory
 import org.junit.jupiter.api.TestInstance
+import org.junit.jupiter.api.fail
 import java.io.BufferedReader
 import java.io.InputStreamReader
 import java.lang.management.ManagementFactory
@@ -24,6 +25,7 @@ enum class TransportType {
     WEBSOCKET,
 }
 
+@Suppress("ForbiddenComment")
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
 class ConformanceTest {
 
@@ -158,7 +160,7 @@ class ConformanceTest {
                 }
             }
             serverProcess?.destroyForcibly()
-            throw IllegalStateException(
+            error(
                 "Server failed to start within $DEFAULT_SERVER_STARTUP_TIMEOUT_SECONDS seconds. " +
                     "Check if port $serverPort is available.$errorInfo",
             )
@@ -307,8 +309,9 @@ class ConformanceTest {
                 "$capitalizedType conformance test [$transportType] '$scenario' timed out after $timeoutSeconds seconds"
             }
             process.destroyForcibly()
-            throw AssertionError(
-                "❌ $capitalizedType conformance test [$transportType] '$scenario' timed out after $timeoutSeconds seconds",
+            fail(
+                "❌ $capitalizedType conformance test [$transportType] '$scenario' " +
+                    "timed out after $timeoutSeconds seconds",
             )
         }
 
@@ -319,8 +322,9 @@ class ConformanceTest {
                 logger.error {
                     "$capitalizedType conformance test [$transportType] '$scenario' failed with exit code: $exitCode"
                 }
-                throw AssertionError(
-                    "❌ $capitalizedType conformance test [$transportType] '$scenario' failed (exit code: $exitCode). Check test output above for details.",
+                fail(
+                    "❌ $capitalizedType conformance test [$transportType] '$scenario' failed (exit code: $exitCode). " +
+                        "Check test output above for details.",
                 )
             }
         }

conformance-test/src/test/kotlin/io/modelcontextprotocol/kotlin/sdk/conformance/WebSocketConformanceClient.kt

@@ -24,6 +24,7 @@ class WebSocketClientTransport(override val session: WebSocketSession) : WebSock
     }
 }
 
+@Suppress("LongMethod")
 fun main(args: Array<String>) {
     require(args.isNotEmpty()) {
         "Server WebSocket URL must be provided as an argument"

detekt.yml

@@ -0,0 +1,7 @@
+config:
+  validation: true
+  warningsAsErrors: true
+
+complexity:
+  LongMethod:
+    excludes: ['**Test.kt']

gradle/libs.versions.toml

@@ -1,13 +1,14 @@
 [versions]
 # plugins version
-kotlin = "2.2.21"
-dokka = "2.1.0"
 atomicfu = "0.29.0"
-ktlint = "14.0.1"
+binaryCompatibilityValidatorPlugin = "0.18.1"
+detekt = "2.0.0-alpha.1"
+dokka = "2.1.0"
+kotlin = "2.2.21"
 kover = "0.9.4"
-netty = "4.2.9.Final"
+ktlint = "14.0.1"
 mavenPublish = "0.35.0"
-binaryCompatibilityValidatorPlugin = "0.18.1"
+netty = "4.2.9.Final"
 openapi-generator = "7.18.0"
 
 # libraries version
@@ -69,6 +70,7 @@ ktor-client-cio = { group = "io.ktor", name = "ktor-client-cio", version.ref = "
 ktor-server-cio = { group = "io.ktor", name = "ktor-server-cio", version.ref = "ktor" }
 
 [plugins]
+detekt = { id = "dev.detekt", version.ref = "detekt" }
 kotlinx-binary-compatibility-validator = { id = "org.jetbrains.kotlinx.binary-compatibility-validator", version.ref = "binaryCompatibilityValidatorPlugin" }
 kover = { id = "org.jetbrains.kotlinx.kover", version.ref = "kover" }
 ktlint = { id = "org.jlleitschuh.gradle.ktlint", version.ref = "ktlint" }

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

@@ -58,7 +58,7 @@ abstract class TsTestBase {
             if (sharedSseServer == null || !sharedSseServer!!.isAlive) {
                 sharedSsePort = io.modelcontextprotocol.kotlin.test.utils.findFreePort()
                 val server = TypeScriptServer(typescriptDir)
-                sharedSseServer = server.startSse(sharedSsePort)
+                sharedSseServer = server.startSseServer(sharedSsePort)
                 println("Shared TypeScript SSE server started on port $sharedSsePort")
 
                 Runtime.getRuntime().addShutdownHook(
@@ -161,7 +161,7 @@ abstract class TsTestBase {
     // ===== STDIO client + server helpers =====
     protected fun startTypeScriptServerStdio(): Process {
         val server = TypeScriptServer(typescriptDir)
-        return server.startStdio()
+        return server.startStdioServer()
     }
 
     protected suspend fun newClientStdio(process: Process): Client {
@@ -193,7 +193,7 @@ abstract class TsTestBase {
     // ===== Helpers to run TypeScript client over STDIO against Kotlin server over STDIO =====
     protected fun runStdioClient(vararg args: String): String = tsClient.use { client ->
         // Start Node stdio client (it will speak MCP over its stdout/stdin)
-        val process = client.startStdio(args.toList(), log = false)
+        val process = client.startStdioClient(args.toList(), log = false)
 
         // Create Kotlin server and attach stdio transport to the process streams
         val server: Server = KotlinServerForTsClient().createMcpServer()

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

@@ -20,7 +20,7 @@ class TypeScriptClient(private val typescriptDir: File) : AutoCloseable {
      * @param log Whether to automatically log process output/error
      * @return The started Process
      */
-    fun startSse(arguments: List<String>, log: Boolean = true): Process {
+    fun startSseClient(arguments: List<String>, log: Boolean = true): Process {
         val scriptPath = File(typescriptDir, "client/sse-client.ts").absolutePath
         val proc = TypeScriptRunner.run(
             typescriptDir = typescriptDir,
@@ -42,7 +42,7 @@ class TypeScriptClient(private val typescriptDir: File) : AutoCloseable {
      * @param log Whether to automatically log process output/error
      * @return The started Process
      */
-    fun startStdio(arguments: List<String>, log: Boolean = true): Process {
+    fun startStdioClient(arguments: List<String>, log: Boolean = true): Process {
         val scriptPath = File(typescriptDir, "client/stdio-client.ts").absolutePath
         val proc = TypeScriptRunner.run(
             typescriptDir = typescriptDir,

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

@@ -44,7 +44,7 @@ class TypeScriptServer(private val typescriptDir: File) {
      * @return The started Process
      * @throws IllegalStateException if the server fails to start within timeout
      */
-    fun startSse(port: Int): Process {
+    fun startSseServer(port: Int): Process {
         killProcessOnPort(port)
         val serverPath = File(typescriptDir, "server/sse-server.ts").absolutePath
         val proc = TypeScriptRunner.run(
@@ -68,7 +68,7 @@ class TypeScriptServer(private val typescriptDir: File) {
      *
      * @return The started Process
      */
-    fun startStdio(): Process {
+    fun startStdioServer(): Process {
         val serverPath = File(typescriptDir, "server/stdio-server.ts").absolutePath
         val proc = TypeScriptRunner.run(
             typescriptDir = typescriptDir,

integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/sse/TsClientKotlinServerTestSse.kt

@@ -36,7 +36,7 @@ class TsClientKotlinServerTestSse : AbstractTsClientKotlinServerTest() {
     }
 
     override fun runClient(vararg args: String): String = tsClient.use { client ->
-        val process = client.startSse(listOf(serverUrl) + args.toList(), log = true)
+        val process = client.startSseClient(listOf(serverUrl) + args.toList(), log = true)
         val output = StringBuilder()
         process.inputStream.bufferedReader().useLines { lines ->
             lines.forEach { line ->

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/OldSchemaCallToolResultUtilsTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk
 
 import kotlinx.serialization.json.JsonPrimitive

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/OldSchemaRequestSerializerTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk
 
 import io.modelcontextprotocol.kotlin.sdk.shared.McpJson

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/OldSchemaToolSerializationTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk
 
 import io.kotest.assertions.json.shouldEqualJson
@@ -419,7 +421,7 @@ class OldSchemaToolSerializationTest {
         name: String = "get_weather",
         title: String? = null,
         outputSchema: String? = null,
-        @Suppress("LocalVariableName") _meta: String? = null,
+        meta: String? = null,
     ): String {
         val stringBuilder = StringBuilder()
 
@@ -466,7 +468,7 @@ class OldSchemaToolSerializationTest {
             .appendLine(",")
             .append(
                 """
-                "_meta": ${_meta ?: "{}"}
+                "_meta": ${meta ?: "{}"}
                 """.trimIndent(),
             )
 
@@ -481,7 +483,7 @@ class OldSchemaToolSerializationTest {
         name: String = "get_weather",
         title: String? = null,
         outputSchema: ToolSchema? = null,
-        @Suppress("LocalVariableName") _meta: JsonObject? = null,
+        meta: JsonObject? = null,
     ): io.modelcontextprotocol.kotlin.sdk.types.Tool = Tool(
         name = name,
         title = title,
@@ -500,7 +502,7 @@ class OldSchemaToolSerializationTest {
             required = listOf("location"),
         ),
         outputSchema = outputSchema,
-        _meta = _meta ?: EmptyJsonObject,
+        _meta = meta ?: EmptyJsonObject,
     )
 
     //endregion Private Methods

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/OldSchemaTypesTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk
 
 import io.modelcontextprotocol.kotlin.sdk.shared.McpJson

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/models/OldSchemaProgressNotificationsTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk.models
 
 import io.kotest.matchers.shouldBe

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/OldSchemaReadBufferTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk.shared
 
 import io.ktor.utils.io.charsets.Charsets

kotlin-sdk-core/src/commonTest/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/ProtocolTest.kt

@@ -154,17 +154,25 @@ class ProtocolTest {
 }
 
 private class TestProtocol : Protocol(null) {
-    override fun assertCapabilityForMethod(method: Method) {}
-    override fun assertNotificationCapability(method: Method) {}
-    override fun assertRequestHandlerCapability(method: Method) {}
+    override fun assertCapabilityForMethod(method: Method) {
+        // noop
+    }
+    override fun assertNotificationCapability(method: Method) {
+        // noop
+    }
+    override fun assertRequestHandlerCapability(method: Method) {
+        // noop
+    }
 }
 
 private class RecordingTransport : Transport {
     private val sentMessages = Channel<JSONRPCMessage>(Channel.UNLIMITED)
     private var onMessageCallback: (suspend (JSONRPCMessage) -> Unit)? = null
     private var onCloseCallback: (() -> Unit)? = null
 
-    override suspend fun start() {}
+    override suspend fun start() {
+        // noop
+    }
 
     override suspend fun send(message: JSONRPCMessage, options: TransportSendOptions?) {
         sentMessages.send(message)
@@ -178,7 +186,9 @@ private class RecordingTransport : Transport {
         onCloseCallback = block
     }
 
-    override fun onError(block: (Throwable) -> Unit) {}
+    override fun onError(block: (Throwable) -> Unit) {
+        // noop
+    }
 
     override fun onMessage(block: suspend (JSONRPCMessage) -> Unit) {
         onMessageCallback = block

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

@@ -68,15 +68,17 @@ private data class SessionContext(val session: ServerSSESession?, val call: Appl
  * @param enableJsonResponse If true, the server will return JSON responses instead of starting an SSE stream.
  * This can be useful for simple request/response scenarios without streaming.
  * Default is false (SSE streams are preferred).
- * @param enableDnsRebindingProtection Enable DNS rebinding protection (requires allowedHosts and/or allowedOrigins to be configured).
+ * @param enableDnsRebindingProtection Enable DNS rebinding protection (requires allowedHosts
+ * and/or allowedOrigins to be configured).
  * Default is false for backwards compatibility.
  * @param allowedHosts List of allowed host header values for DNS rebinding protection.
  * If not specified, host validation is disabled.
  * @param allowedOrigins List of allowed origin header values for DNS rebinding protection.
  * If not specified, origin validation is disabled.
  * @param eventStore Event store for resumability support
  * If provided, resumability will be enabled, allowing clients to reconnect and resume messages
- * @param retryIntervalMillis Retry interval (in milliseconds) advertised via SSE priming events to hint the client when to reconnect.
+ * @param retryIntervalMillis Retry interval (in milliseconds) advertised via SSE priming events to hint the client
+ * when to reconnect.
  * Applies only when an [eventStore] is configured. Defaults to `null` (no retry hint).
  */
 @OptIn(ExperimentalUuidApi::class, ExperimentalAtomicApi::class)
@@ -107,6 +109,7 @@ public class StreamableHttpServerTransport(
 
     private companion object {
         const val STANDALONE_SSE_STREAM_ID = "_GET_stream"
+        private const val ONE_MEGABYTE = 1024 * 1024
     }
 
     /**
@@ -145,7 +148,8 @@ public class StreamableHttpServerTransport(
 
     override suspend fun start() {
         check(started.compareAndSet(expectedValue = false, newValue = true)) {
-            "StreamableHttpServerTransport already started! If using Server class, note that connect() calls start() automatically."
+            "StreamableHttpServerTransport already started! If using Server class, " +
+                "note that connect() calls start() automatically."
         }
     }
 
@@ -585,7 +589,7 @@ public class StreamableHttpServerTransport(
             call.reject(
                 HttpStatusCode.PayloadTooLarge,
                 RPCError.ErrorCode.INVALID_REQUEST,
-                "Invalid Request: message size exceeds maximum of ${MAXIMUM_MESSAGE_SIZE / (1024 * 1024)} MB",
+                "Invalid Request: message size exceeds maximum of ${MAXIMUM_MESSAGE_SIZE / ONE_MEGABYTE} MB",
             )
             return null
         }
@@ -595,7 +599,7 @@ public class StreamableHttpServerTransport(
             call.reject(
                 HttpStatusCode.PayloadTooLarge,
                 RPCError.ErrorCode.INVALID_REQUEST,
-                "Invalid Request: message size exceeds maximum of ${MAXIMUM_MESSAGE_SIZE / (1024 * 1024)} MB",
+                "Invalid Request: message size exceeds maximum of ${MAXIMUM_MESSAGE_SIZE / (ONE_MEGABYTE)} MB",
             )
             return null
         }

kotlin-sdk-server/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/OldSchemaStdioServerTransportTest.kt

@@ -1,3 +1,5 @@
+@file:Suppress("DEPRECATION")
+
 package io.modelcontextprotocol.kotlin.sdk.server
 
 import io.modelcontextprotocol.kotlin.sdk.InitializedNotification