feat: add ignorable JSON-RPC methods support for both client and server

mcp-test/src/main/java/io/modelcontextprotocol/client/AbstractMcpAsyncClientTests.java

@@ -830,4 +830,35 @@ void testProgressConsumer() {
 		});
 	}
 
+	// Tests for ignorable JSON-RPC methods feature
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderList() {
+		List<String> customIgnorables = List.of("custom/method1", "custom/method2");
+
+		withClient(createMcpTransport(), builder -> builder.ignorableJsonRpcMethods(customIgnorables), client -> {
+			StepVerifier.create(client.initialize()).expectNextMatches(Objects::nonNull).verifyComplete();
+		});
+	}
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderVarargs() {
+		withClient(createMcpTransport(),
+				builder -> builder.ignorableJsonRpcMethods("custom/method1", "custom/method2", "custom/method3"),
+				client -> {
+					StepVerifier.create(client.initialize()).expectNextMatches(Objects::nonNull).verifyComplete();
+				});
+	}
+
+	@Test
+	void testIgnorableMethodsBuilderNullValidation() {
+		assertThatThrownBy(() -> McpClient.async(createMcpTransport()).ignorableJsonRpcMethods((List<String>) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+
+		assertThatThrownBy(() -> McpClient.async(createMcpTransport()).ignorableJsonRpcMethods((String[]) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+	}
+
 }

mcp-test/src/main/java/io/modelcontextprotocol/client/AbstractMcpSyncClientTests.java

@@ -695,4 +695,35 @@ void testProgressConsumer() {
 		});
 	}
 
+	// Tests for ignorable JSON-RPC methods feature
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderList() {
+		List<String> customIgnorables = List.of("custom/method1", "custom/method2");
+
+		withClient(createMcpTransport(), builder -> builder.ignorableJsonRpcMethods(customIgnorables), client -> {
+			assertThatCode(() -> client.initialize()).doesNotThrowAnyException();
+		});
+	}
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderVarargs() {
+		withClient(createMcpTransport(),
+				builder -> builder.ignorableJsonRpcMethods("custom/method1", "custom/method2", "custom/method3"),
+				client -> {
+					assertThatCode(() -> client.initialize()).doesNotThrowAnyException();
+				});
+	}
+
+	@Test
+	void testIgnorableMethodsBuilderNullValidation() {
+		assertThatThrownBy(() -> McpClient.sync(createMcpTransport()).ignorableJsonRpcMethods((List<String>) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+
+		assertThatThrownBy(() -> McpClient.sync(createMcpTransport()).ignorableJsonRpcMethods((String[]) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+	}
+
 }

mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java

@@ -522,4 +522,44 @@ void testRootsChangeHandlers() {
 			.doesNotThrowAnyException();
 	}
 
+	// ---------------------------------------
+	// Ignorable JSON-RPC Methods Tests
+	// ---------------------------------------
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderList() {
+		List<String> customIgnorables = List.of("custom/method1", "custom/method2");
+
+		var server = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.ignorableJsonRpcMethods(customIgnorables)
+			.build();
+
+		assertThat(server).isNotNull();
+		assertThatCode(() -> server.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderVarargs() {
+		var server = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.ignorableJsonRpcMethods("custom/method1", "custom/method2", "custom/method3")
+			.build();
+
+		assertThat(server).isNotNull();
+		assertThatCode(() -> server.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testIgnorableMethodsBuilderNullValidation() {
+		assertThatThrownBy(
+				() -> McpServer.async(createMcpTransportProvider()).ignorableJsonRpcMethods((List<String>) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider()).ignorableJsonRpcMethods((String[]) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+	}
+
 }

mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java

@@ -492,4 +492,44 @@ void testRootsChangeHandlers() {
 		assertThatCode(() -> noConsumersServer.closeGracefully()).doesNotThrowAnyException();
 	}
 
+	// ---------------------------------------
+	// Ignorable JSON-RPC Methods Tests
+	// ---------------------------------------
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderList() {
+		List<String> customIgnorables = List.of("custom/method1", "custom/method2");
+
+		var server = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.ignorableJsonRpcMethods(customIgnorables)
+			.build();
+
+		assertThat(server).isNotNull();
+		assertThatCode(() -> server.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testIgnorableJsonRpcMethodsBuilderVarargs() {
+		var server = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.ignorableJsonRpcMethods("custom/method1", "custom/method2", "custom/method3")
+			.build();
+
+		assertThat(server).isNotNull();
+		assertThatCode(() -> server.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testIgnorableMethodsBuilderNullValidation() {
+		assertThatThrownBy(
+				() -> McpServer.sync(createMcpTransportProvider()).ignorableJsonRpcMethods((List<String>) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider()).ignorableJsonRpcMethods((String[]) null))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Ignorable JSON-RPC methods must not be null");
+	}
+
 }

mcp/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java

@@ -159,7 +159,7 @@ public class McpAsyncClient {
 	 * @param features the MCP Client supported features.
 	 */
 	McpAsyncClient(McpClientTransport transport, Duration requestTimeout, Duration initializationTimeout,
-			McpClientFeatures.Async features) {
+			McpClientFeatures.Async features, List<String> ignorableJsonRpcMethods) {
 
 		Assert.notNull(transport, "Transport must not be null");
 		Assert.notNull(requestTimeout, "Request timeout must not be null");
@@ -269,7 +269,7 @@ public class McpAsyncClient {
 		this.initializer = new LifecycleInitializer(clientCapabilities, clientInfo,
 				List.of(McpSchema.LATEST_PROTOCOL_VERSION), initializationTimeout,
 				ctx -> new McpClientSession(requestTimeout, transport, requestHandlers, notificationHandlers,
-						con -> con.contextWrite(ctx)));
+						con -> con.contextWrite(ctx), ignorableJsonRpcMethods));
 		this.transport.setExceptionHandler(this.initializer::handleException);
 	}
 

mcp/src/main/java/io/modelcontextprotocol/client/McpClient.java

@@ -23,6 +23,7 @@
 import io.modelcontextprotocol.spec.McpSchema.Implementation;
 import io.modelcontextprotocol.spec.McpSchema.Root;
 import io.modelcontextprotocol.util.Assert;
+import io.modelcontextprotocol.util.Utils;
 import reactor.core.publisher.Mono;
 
 /**
@@ -161,6 +162,12 @@ class SyncSpec {
 
 		private Duration initializationTimeout = Duration.ofSeconds(20);
 
+		/**
+		 * List of JSON-RPC methods that can be ignored. These methods will not be
+		 * processed and will not generate errors if received
+		 */
+		private final List<String> ignorableJsonRpcMethods = new ArrayList<>(Utils.DEFAULT_IGNORABLE_JSON_RPC_METHODS);
+
 		private ClientCapabilities capabilities;
 
 		private Implementation clientInfo = new Implementation("Java SDK MCP Client", "1.0.0");
@@ -215,6 +222,36 @@ public SyncSpec initializationTimeout(Duration initializationTimeout) {
 			return this;
 		}
 
+		/**
+		 * Sets the list of JSON-RPC methods that can be ignored by the client. These
+		 * methods will not be processed and will not generate errors if received.
+		 * @param ignorableJsonRpcMethods A list of JSON-RPC method names to ignore. Must
+		 * not be null.
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if ignorableJsonRpcMethods is null
+		 */
+		public SyncSpec ignorableJsonRpcMethods(List<String> ignorableJsonRpcMethods) {
+			Assert.notNull(ignorableJsonRpcMethods, "Ignorable JSON-RPC methods must not be null");
+			this.ignorableJsonRpcMethods.addAll(ignorableJsonRpcMethods);
+			return this;
+		}
+
+		/**
+		 * Sets the list of JSON-RPC methods that can be ignored by the client. These
+		 * methods will not be processed and will not generate errors if received.
+		 * @param ignorableJsonRpcMethods An array of JSON-RPC method names to ignore.
+		 * Must not be null.
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if ignorableJsonRpcMethods is null
+		 */
+		public SyncSpec ignorableJsonRpcMethods(String... ignorableJsonRpcMethods) {
+			Assert.notNull(ignorableJsonRpcMethods, "Ignorable JSON-RPC methods must not be null");
+			for (String method : ignorableJsonRpcMethods) {
+				this.ignorableJsonRpcMethods.add(method);
+			}
+			return this;
+		}
+
 		/**
 		 * Sets the client capabilities that will be advertised to the server during
 		 * connection initialization. Capabilities define what features the client
@@ -422,8 +459,8 @@ public McpSyncClient build() {
 
 			McpClientFeatures.Async asyncFeatures = McpClientFeatures.Async.fromSync(syncFeatures);
 
-			return new McpSyncClient(
-					new McpAsyncClient(transport, this.requestTimeout, this.initializationTimeout, asyncFeatures));
+			return new McpSyncClient(new McpAsyncClient(transport, this.requestTimeout, this.initializationTimeout,
+					asyncFeatures, this.ignorableJsonRpcMethods));
 		}
 
 	}
@@ -452,6 +489,12 @@ class AsyncSpec {
 
 		private Duration initializationTimeout = Duration.ofSeconds(20);
 
+		/**
+		 * List of JSON-RPC methods that can be ignored. These methods will not be
+		 * processed and will not generate errors if received
+		 */
+		private final List<String> ignorableJsonRpcMethods = new ArrayList<>(Utils.DEFAULT_IGNORABLE_JSON_RPC_METHODS);
+
 		private ClientCapabilities capabilities;
 
 		private Implementation clientInfo = new Implementation("Spring AI MCP Client", "0.3.1");
@@ -506,6 +549,36 @@ public AsyncSpec initializationTimeout(Duration initializationTimeout) {
 			return this;
 		}
 
+		/**
+		 * Sets the list of JSON-RPC methods that can be ignored by the client. These
+		 * methods will not be processed and will not generate errors if received.
+		 * @param ignorableJsonRpcMethods A list of JSON-RPC method names to ignore. Must
+		 * not be null.
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if ignorableJsonRpcMethods is null
+		 */
+		public AsyncSpec ignorableJsonRpcMethods(List<String> ignorableJsonRpcMethods) {
+			Assert.notNull(ignorableJsonRpcMethods, "Ignorable JSON-RPC methods must not be null");
+			this.ignorableJsonRpcMethods.addAll(ignorableJsonRpcMethods);
+			return this;
+		}
+
+		/**
+		 * Sets the list of JSON-RPC methods that can be ignored by the client. These
+		 * methods will not be processed and will not generate errors if received.
+		 * @param ignorableJsonRpcMethods An array of JSON-RPC method names to ignore.
+		 * Must not be null.
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if ignorableJsonRpcMethods is null
+		 */
+		public AsyncSpec ignorableJsonRpcMethods(String... ignorableJsonRpcMethods) {
+			Assert.notNull(ignorableJsonRpcMethods, "Ignorable JSON-RPC methods must not be null");
+			for (String method : ignorableJsonRpcMethods) {
+				this.ignorableJsonRpcMethods.add(method);
+			}
+			return this;
+		}
+
 		/**
 		 * Sets the client capabilities that will be advertised to the server during
 		 * connection initialization. Capabilities define what features the client
@@ -730,7 +803,8 @@ public McpAsyncClient build() {
 					new McpClientFeatures.Async(this.clientInfo, this.capabilities, this.roots,
 							this.toolsChangeConsumers, this.resourcesChangeConsumers, this.resourcesUpdateConsumers,
 							this.promptsChangeConsumers, this.loggingConsumers, this.progressConsumers,
-							this.samplingHandler, this.elicitationHandler));
+							this.samplingHandler, this.elicitationHandler),
+					this.ignorableJsonRpcMethods);
 		}
 
 	}

mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java

@@ -116,6 +116,8 @@ public class McpAsyncServer {
 
 	private McpUriTemplateManagerFactory uriTemplateManagerFactory = new DeafaultMcpUriTemplateManagerFactory();
 
+	private final List<String> ignorableJsonRpcMethods;
+
 	/**
 	 * Create a new McpAsyncServer with the given transport provider and capabilities.
 	 * @param mcpTransportProvider The transport layer implementation for MCP
@@ -126,6 +128,22 @@ public class McpAsyncServer {
 	McpAsyncServer(McpServerTransportProvider mcpTransportProvider, ObjectMapper objectMapper,
 			McpServerFeatures.Async features, Duration requestTimeout,
 			McpUriTemplateManagerFactory uriTemplateManagerFactory, JsonSchemaValidator jsonSchemaValidator) {
+		this(mcpTransportProvider, objectMapper, features, requestTimeout, uriTemplateManagerFactory,
+				jsonSchemaValidator, Utils.DEFAULT_IGNORABLE_JSON_RPC_METHODS);
+	}
+
+	/**
+	 * Create a new McpAsyncServer with the given transport provider and capabilities.
+	 * @param mcpTransportProvider The transport layer implementation for MCP
+	 * communication.
+	 * @param features The MCP server supported features.
+	 * @param objectMapper The ObjectMapper to use for JSON serialization/deserialization
+	 * @param ignorableJsonRpcMethods List of JSON-RPC method names that should be ignored
+	 */
+	McpAsyncServer(McpServerTransportProvider mcpTransportProvider, ObjectMapper objectMapper,
+			McpServerFeatures.Async features, Duration requestTimeout,
+			McpUriTemplateManagerFactory uriTemplateManagerFactory, JsonSchemaValidator jsonSchemaValidator,
+			List<String> ignorableJsonRpcMethods) {
 		this.mcpTransportProvider = mcpTransportProvider;
 		this.objectMapper = objectMapper;
 		this.serverInfo = features.serverInfo();
@@ -138,6 +156,8 @@ public class McpAsyncServer {
 		this.completions.putAll(features.completions());
 		this.uriTemplateManagerFactory = uriTemplateManagerFactory;
 		this.jsonSchemaValidator = jsonSchemaValidator;
+		this.ignorableJsonRpcMethods = ignorableJsonRpcMethods != null ? List.copyOf(ignorableJsonRpcMethods)
+				: List.of();
 
 		Map<String, McpServerSession.RequestHandler<?>> requestHandlers = new HashMap<>();
 
@@ -190,9 +210,9 @@ public class McpAsyncServer {
 		notificationHandlers.put(McpSchema.METHOD_NOTIFICATION_ROOTS_LIST_CHANGED,
 				asyncRootsListChangedNotificationHandler(rootsChangeConsumers));
 
-		mcpTransportProvider.setSessionFactory(
-				transport -> new McpServerSession(UUID.randomUUID().toString(), requestTimeout, transport,
-						this::asyncInitializeRequestHandler, Mono::empty, requestHandlers, notificationHandlers));
+		mcpTransportProvider.setSessionFactory(transport -> new McpServerSession(UUID.randomUUID().toString(),
+				requestTimeout, transport, this::asyncInitializeRequestHandler, Mono::empty, requestHandlers,
+				notificationHandlers, this.ignorableJsonRpcMethods));
 	}
 
 	// ---------------------------------------