diff --git a/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxSseIntegrationTests.java b/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxSseIntegrationTests.java
index 73aff4629..29a1f76a0 100644
--- a/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxSseIntegrationTests.java
+++ b/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxSseIntegrationTests.java
@@ -3,6 +3,12 @@
  */
 package io.modelcontextprotocol;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertWith;
+import static org.awaitility.Awaitility.await;
+import static org.mockito.Mockito.mock;
+
 import java.time.Duration;
 import java.util.List;
 import java.util.Map;
@@ -15,39 +21,50 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.springframework.http.server.reactive.HttpHandler;
+import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.server.RouterFunctions;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import io.modelcontextprotocol.client.McpClient;
 import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
 import io.modelcontextprotocol.client.transport.WebFluxSseClientTransport;
 import io.modelcontextprotocol.server.McpServer;
 import io.modelcontextprotocol.server.McpServerFeatures;
-import io.modelcontextprotocol.server.TestUtil;
 import io.modelcontextprotocol.server.McpSyncServerExchange;
+import io.modelcontextprotocol.server.TestUtil;
 import io.modelcontextprotocol.server.transport.WebFluxSseServerTransportProvider;
 import io.modelcontextprotocol.spec.McpError;
 import io.modelcontextprotocol.spec.McpSchema;
-import io.modelcontextprotocol.spec.McpSchema.*;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.ValueSource;
+import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
+import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
+import io.modelcontextprotocol.spec.McpSchema.CompleteRequest;
+import io.modelcontextprotocol.spec.McpSchema.CompleteResult;
+import io.modelcontextprotocol.spec.McpSchema.CreateMessageRequest;
+import io.modelcontextprotocol.spec.McpSchema.CreateMessageResult;
+import io.modelcontextprotocol.spec.McpSchema.ElicitRequest;
+import io.modelcontextprotocol.spec.McpSchema.ElicitResult;
+import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+import io.modelcontextprotocol.spec.McpSchema.ModelPreferences;
+import io.modelcontextprotocol.spec.McpSchema.Prompt;
+import io.modelcontextprotocol.spec.McpSchema.PromptArgument;
+import io.modelcontextprotocol.spec.McpSchema.PromptReference;
+import io.modelcontextprotocol.spec.McpSchema.Role;
+import io.modelcontextprotocol.spec.McpSchema.Root;
+import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
+import io.modelcontextprotocol.spec.McpSchema.Tool;
 import reactor.core.publisher.Mono;
 import reactor.netty.DisposableServer;
 import reactor.netty.http.server.HttpServer;
-
-import org.springframework.http.server.reactive.HttpHandler;
-import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
-import org.springframework.web.client.RestClient;
-import org.springframework.web.reactive.function.client.WebClient;
-import org.springframework.web.reactive.function.server.RouterFunctions;
 import reactor.test.StepVerifier;
 
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.assertj.core.api.Assertions.assertWith;
-import static org.awaitility.Awaitility.await;
-import static org.mockito.Mockito.mock;
-
 class WebFluxSseIntegrationTests {
 
 	private static final int PORT = TestUtil.findAvailablePort();
@@ -103,10 +120,11 @@ void testCreateMessageWithoutSamplingCapabilities(String clientType) {
 
 		var clientBuilder = clientBuilders.get(clientType);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema),
-				(exchange, request) -> exchange.createMessage(mock(CreateMessageRequest.class))
-					.thenReturn(mock(CallToolResult.class)));
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> exchange.createMessage(mock(CreateMessageRequest.class))
+				.thenReturn(mock(CallToolResult.class)))
+			.build();
 
 		var server = McpServer.async(mcpServerTransportProvider).serverInfo("test-server", "1.0.0").tools(tool).build();
 
@@ -145,24 +163,26 @@ void testCreateMessageSuccess(String clientType) {
 
 		AtomicReference<CreateMessageResult> samplingResult = new AtomicReference<>();
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var createMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					return exchange.createMessage(createMessageRequest)
-						.doOnNext(samplingResult::set)
-						.thenReturn(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var createMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				return exchange.createMessage(createMessageRequest)
+					.doOnNext(samplingResult::set)
+					.thenReturn(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -221,24 +241,26 @@ void testCreateMessageWithRequestTimeoutSuccess(String clientType) throws Interr
 
 		AtomicReference<CreateMessageResult> samplingResult = new AtomicReference<>();
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					return exchange.createMessage(craeteMessageRequest)
-						.doOnNext(samplingResult::set)
-						.thenReturn(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				return exchange.createMessage(craeteMessageRequest)
+					.doOnNext(samplingResult::set)
+					.thenReturn(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.requestTimeout(Duration.ofSeconds(4))
@@ -297,16 +319,18 @@ void testCreateMessageWithRequestTimeoutFail(String clientType) throws Interrupt
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.build();
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.build();
 
-					return exchange.createMessage(craeteMessageRequest).thenReturn(callResponse);
-				});
+				return exchange.createMessage(craeteMessageRequest).thenReturn(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.requestTimeout(Duration.ofSeconds(1))
@@ -340,13 +364,15 @@ void testCreateElicitationWithoutElicitationCapabilities(String clientType) {
 
 		var clientBuilder = clientBuilders.get(clientType);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.createElicitation(mock(ElicitRequest.class)).block();
+				exchange.createElicitation(mock(ElicitRequest.class)).block();
 
-					return Mono.just(mock(CallToolResult.class));
-				});
+				return Mono.just(mock(CallToolResult.class));
+			})
+			.build();
 
 		var server = McpServer.async(mcpServerTransportProvider).serverInfo("test-server", "1.0.0").tools(tool).build();
 
@@ -383,23 +409,25 @@ void testCreateElicitationSuccess(String clientType) {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -445,23 +473,25 @@ void testCreateElicitationWithRequestTimeoutSuccess(String clientType) {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -514,23 +544,25 @@ void testCreateElicitationWithRequestTimeoutFail(String clientType) {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -605,13 +637,15 @@ void testRootsWithoutCapability(String clientType) {
 
 		var clientBuilder = clientBuilders.get(clientType);
 
-		McpServerFeatures.SyncToolSpecification tool = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.SyncToolSpecification tool = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.listRoots(); // try to list roots
+				exchange.listRoots(); // try to list roots
 
-					return mock(CallToolResult.class);
-				});
+				return mock(CallToolResult.class);
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider).rootsChangeHandler((exchange, rootsUpdate) -> {
 		}).tools(tool).build();
@@ -744,17 +778,19 @@ void testToolCallSuccess(String clientType) {
 		var clientBuilder = clientBuilders.get(clientType);
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().tools(true).build())
@@ -784,17 +820,19 @@ void testToolListChangeHandlingSuccess(String clientType) {
 		var clientBuilder = clientBuilders.get(clientType);
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		AtomicReference<List<Tool>> rootsRef = new AtomicReference<>();
 
@@ -835,9 +873,10 @@ void testToolListChangeHandlingSuccess(String clientType) {
 			});
 
 			// Add a new tool
-			McpServerFeatures.SyncToolSpecification tool2 = new McpServerFeatures.SyncToolSpecification(
-					new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema),
-					(exchange, request) -> callResponse);
+			McpServerFeatures.SyncToolSpecification tool2 = McpServerFeatures.SyncToolSpecification.builder()
+				.tool(new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema))
+				.callTool((exchange, request) -> callResponse)
+				.build();
 
 			mcpServer.addTool(tool2);
 
@@ -880,13 +919,13 @@ void testLoggingNotification(String clientType) throws InterruptedException {
 		var clientBuilder = clientBuilders.get(clientType);
 
 		// Create server with a tool that sends logging notifications
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("logging-test", "Test logging notifications", emptyJsonSchema),
-				(exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("logging-test", "Test logging notifications", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					// Create and send notifications with different levels
+				// Create and send notifications with different levels
 
-				//@formatter:off
+			//@formatter:off
 					return exchange // This should be filtered out (DEBUG < NOTICE)
 						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
 								.level(McpSchema.LoggingLevel.DEBUG)
@@ -919,7 +958,8 @@ void testLoggingNotification(String clientType) throws InterruptedException {
 								.build()))
 					.thenReturn(new CallToolResult("Logging test completed", false));
 					//@formatter:on
-				});
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -1034,26 +1074,27 @@ void testPingSuccess(String clientType) {
 		// Create server with a tool that uses ping functionality
 		AtomicReference<String> executionOrder = new AtomicReference<>("");
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("ping-async-test", "Test ping async behavior", emptyJsonSchema),
-				(exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("ping-async-test", "Test ping async behavior", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					executionOrder.set(executionOrder.get() + "1");
+				executionOrder.set(executionOrder.get() + "1");
 
-					// Test async ping behavior
-					return exchange.ping().doOnNext(result -> {
+				// Test async ping behavior
+				return exchange.ping().doOnNext(result -> {
 
-						assertThat(result).isNotNull();
-						// Ping should return an empty object or map
-						assertThat(result).isInstanceOf(Map.class);
+					assertThat(result).isNotNull();
+					// Ping should return an empty object or map
+					assertThat(result).isInstanceOf(Map.class);
 
-						executionOrder.set(executionOrder.get() + "2");
-						assertThat(result).isNotNull();
-					}).then(Mono.fromCallable(() -> {
-						executionOrder.set(executionOrder.get() + "3");
-						return new CallToolResult("Async ping test completed", false);
-					}));
-				});
+					executionOrder.set(executionOrder.get() + "2");
+					assertThat(result).isNotNull();
+				}).then(Mono.fromCallable(() -> {
+					executionOrder.set(executionOrder.get() + "3");
+					return new CallToolResult("Async ping test completed", false);
+				}));
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
diff --git a/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcSseIntegrationTests.java b/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcSseIntegrationTests.java
index 43d6f40fe..b92ff7a5b 100644
--- a/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcSseIntegrationTests.java
+++ b/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcSseIntegrationTests.java
@@ -3,6 +3,11 @@
  */
 package io.modelcontextprotocol.server;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.awaitility.Awaitility.await;
+import static org.mockito.Mockito.mock;
+
 import java.time.Duration;
 import java.util.List;
 import java.util.Map;
@@ -10,7 +15,20 @@
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 
+import org.apache.catalina.LifecycleException;
+import org.apache.catalina.LifecycleState;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.function.RouterFunction;
+import org.springframework.web.servlet.function.ServerResponse;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import io.modelcontextprotocol.client.McpClient;
 import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
 import io.modelcontextprotocol.server.transport.WebMvcSseServerTransportProvider;
@@ -26,26 +44,9 @@
 import io.modelcontextprotocol.spec.McpSchema.Root;
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.Tool;
-import org.apache.catalina.LifecycleException;
-import org.apache.catalina.LifecycleState;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.web.client.RestClient;
-import org.springframework.web.servlet.config.annotation.EnableWebMvc;
-import org.springframework.web.servlet.function.RouterFunction;
-import org.springframework.web.servlet.function.ServerResponse;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.awaitility.Awaitility.await;
-import static org.mockito.Mockito.mock;
-
 class WebMvcSseIntegrationTests {
 
 	private static final int PORT = TestUtil.findAvailablePort();
@@ -119,13 +120,13 @@ public void after() {
 	@Test
 	void testCreateMessageWithoutSamplingCapabilities() {
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					exchange.createMessage(mock(McpSchema.CreateMessageRequest.class)).block();
-
-					return Mono.just(mock(CallToolResult.class));
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				exchange.createMessage(mock(McpSchema.CreateMessageRequest.class)).block();
+				return Mono.just(mock(CallToolResult.class));
+			})
+			.build();
 
 		//@formatter:off
 		var server = McpServer.async(mcpServerTransportProvider)
@@ -166,31 +167,33 @@ void testCreateMessageSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var createMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(createMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var createMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(createMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		//@formatter:off		
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
@@ -242,31 +245,33 @@ void testCreateMessageWithRequestTimeoutSuccess() throws InterruptedException {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -314,31 +319,33 @@ void testCreateMessageWithRequestTimeoutFail() throws InterruptedException {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -363,13 +370,15 @@ void testCreateMessageWithRequestTimeoutFail() throws InterruptedException {
 	@Test
 	void testCreateElicitationWithoutElicitationCapabilities() {
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.createElicitation(mock(McpSchema.ElicitRequest.class)).block();
+				exchange.createElicitation(mock(McpSchema.ElicitRequest.class)).block();
 
-					return Mono.just(mock(CallToolResult.class));
-				});
+				return Mono.just(mock(CallToolResult.class));
+			})
+			.build();
 
 		var server = McpServer.async(mcpServerTransportProvider).serverInfo("test-server", "1.0.0").tools(tool).build();
 
@@ -404,23 +413,25 @@ void testCreateElicitationSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = McpSchema.ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = McpSchema.ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -471,23 +482,25 @@ void testCreateElicitationWithRequestTimeoutSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = McpSchema.ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = McpSchema.ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -535,23 +548,25 @@ void testCreateElicitationWithRequestTimeoutFail() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = McpSchema.ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = McpSchema.ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(McpSchema.ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -620,13 +635,15 @@ void testRootsSuccess() {
 	@Test
 	void testRootsWithoutCapability() {
 
-		McpServerFeatures.SyncToolSpecification tool = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.SyncToolSpecification tool = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.listRoots(); // try to list roots
+				exchange.listRoots(); // try to list roots
 
-					return mock(CallToolResult.class);
-				});
+				return mock(CallToolResult.class);
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider).rootsChangeHandler((exchange, rootsUpdate) -> {
 		}).tools(tool).build();
@@ -747,17 +764,19 @@ void testRootsServerCloseWithActiveSubscription() {
 	void testToolCallSuccess() {
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().tools(true).build())
@@ -783,17 +802,19 @@ void testToolCallSuccess() {
 	void testToolListChangeHandlingSuccess() {
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		AtomicReference<List<Tool>> rootsRef = new AtomicReference<>();
 
@@ -834,9 +855,10 @@ void testToolListChangeHandlingSuccess() {
 			});
 
 			// Add a new tool
-			McpServerFeatures.SyncToolSpecification tool2 = new McpServerFeatures.SyncToolSpecification(
-					new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema),
-					(exchange, request) -> callResponse);
+			McpServerFeatures.SyncToolSpecification tool2 = McpServerFeatures.SyncToolSpecification.builder()
+				.tool(new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema))
+				.callTool((exchange, request) -> callResponse)
+				.build();
 
 			mcpServer.addTool(tool2);
 
diff --git a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
index 12827f469..905c473f3 100644
--- a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
+++ b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
@@ -34,7 +34,6 @@
  *
  * @author Christian Tzolov
  */
-// KEEP IN SYNC with the class in mcp-test module
 public abstract class AbstractMcpAsyncServerTests {
 
 	private static final String TEST_TOOL_NAME = "test-tool";
@@ -102,6 +101,7 @@ void testImmediateClose() {
 			""";
 
 	@Test
+	@Deprecated
 	void testAddTool() {
 		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
@@ -117,6 +117,23 @@ void testAddTool() {
 	}
 
 	@Test
+	void testAddToolCall() {
+		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
+		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.build();
+
+		StepVerifier.create(mcpAsyncServer.addTool(McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(newTool)
+			.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build())).verifyComplete();
+
+		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	@Deprecated
 	void testAddDuplicateTool() {
 		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
 
@@ -137,6 +154,83 @@ void testAddDuplicateTool() {
 		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
 	}
 
+	@Test
+	void testAddDuplicateToolCall() {
+		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
+
+		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build();
+
+		StepVerifier.create(mcpAsyncServer.addTool(McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(duplicateTool)
+			.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build())).verifyErrorSatisfies(error -> {
+				assertThat(error).isInstanceOf(McpError.class)
+					.hasMessage("Tool with name '" + TEST_TOOL_NAME + "' already exists");
+			});
+
+		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testDuplicateToolCallDuringBuilding() {
+		Tool duplicateTool = new Tool("duplicate-build-toolcall", "Duplicate toolcall during building",
+				emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false))) // Duplicate!
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'duplicate-build-toolcall' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchListRegistration() {
+		Tool duplicateTool = new Tool("batch-list-tool", "Duplicate tool in batch list", emptyJsonSchema);
+		List<McpServerFeatures.AsyncToolSpecification> specs = List.of(
+				McpServerFeatures.AsyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+					.build(),
+				McpServerFeatures.AsyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+					.build() // Duplicate!
+		);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(specs)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-list-tool' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchVarargsRegistration() {
+		Tool duplicateTool = new Tool("batch-varargs-tool", "Duplicate tool in batch varargs", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(McpServerFeatures.AsyncToolSpecification.builder()
+				.tool(duplicateTool)
+				.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+				.build(),
+					McpServerFeatures.AsyncToolSpecification.builder()
+						.tool(duplicateTool)
+						.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+						.build() // Duplicate!
+			)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-varargs-tool' is already registered.");
+	}
+
 	@Test
 	void testRemoveTool() {
 		Tool too = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
@@ -144,7 +238,7 @@ void testRemoveTool() {
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
 			.build();
 
 		StepVerifier.create(mcpAsyncServer.removeTool(TEST_TOOL_NAME)).verifyComplete();
@@ -173,7 +267,7 @@ void testNotifyToolsListChanged() {
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
 			.build();
 
 		StepVerifier.create(mcpAsyncServer.notifyToolsListChanged()).verifyComplete();
diff --git a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
index eefcdf9a3..a6b4d2f5c 100644
--- a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
+++ b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
@@ -4,8 +4,16 @@
 
 package io.modelcontextprotocol.server;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 import java.util.List;
 
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
 import io.modelcontextprotocol.spec.McpError;
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
@@ -17,21 +25,13 @@
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.Tool;
 import io.modelcontextprotocol.spec.McpServerTransportProvider;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatCode;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * Test suite for the {@link McpSyncServer} that can be used with different
- * {@link io.modelcontextprotocol.spec.McpServerTransportProvider} implementations.
+ * {@link McpTransportProvider} implementations.
  *
  * @author Christian Tzolov
  */
-// KEEP IN SYNC with the class in mcp-test module
 public abstract class AbstractMcpSyncServerTests {
 
 	private static final String TEST_TOOL_NAME = "test-tool";
@@ -109,6 +109,7 @@ void testGetAsyncServer() {
 			""";
 
 	@Test
+	@Deprecated
 	void testAddTool() {
 		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
@@ -124,6 +125,23 @@ void testAddTool() {
 	}
 
 	@Test
+	void testAddToolCall() {
+		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.build();
+
+		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
+		assertThatCode(() -> mcpSyncServer.addTool(McpServerFeatures.SyncToolSpecification.builder()
+			.tool(newTool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+			.build())).doesNotThrowAnyException();
+
+		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	@Deprecated
 	void testAddDuplicateTool() {
 		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
 
@@ -141,6 +159,81 @@ void testAddDuplicateTool() {
 		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
 	}
 
+	@Test
+	void testAddDuplicateToolCall() {
+		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
+
+		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false))
+			.build();
+
+		assertThatThrownBy(() -> mcpSyncServer.addTool(McpServerFeatures.SyncToolSpecification.builder()
+			.tool(duplicateTool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+			.build())).isInstanceOf(McpError.class)
+			.hasMessage("Tool with name '" + TEST_TOOL_NAME + "' already exists");
+
+		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testDuplicateToolCallDuringBuilding() {
+		Tool duplicateTool = new Tool("duplicate-build-toolcall", "Duplicate toolcall during building",
+				emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false))
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false)) // Duplicate!
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'duplicate-build-toolcall' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchListRegistration() {
+		Tool duplicateTool = new Tool("batch-list-tool", "Duplicate tool in batch list", emptyJsonSchema);
+		List<McpServerFeatures.SyncToolSpecification> specs = List.of(
+				McpServerFeatures.SyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+					.build(),
+				McpServerFeatures.SyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+					.build() // Duplicate!
+		);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(specs)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-list-tool' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchVarargsRegistration() {
+		Tool duplicateTool = new Tool("batch-varargs-tool", "Duplicate tool in batch varargs", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(McpServerFeatures.SyncToolSpecification.builder()
+				.tool(duplicateTool)
+				.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+				.build(),
+					McpServerFeatures.SyncToolSpecification.builder()
+						.tool(duplicateTool)
+						.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+						.build() // Duplicate!
+			)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-varargs-tool' is already registered.");
+	}
+
 	@Test
 	void testRemoveTool() {
 		Tool tool = new McpSchema.Tool(TEST_TOOL_NAME, "Test tool", emptyJsonSchema);
@@ -148,7 +241,7 @@ void testRemoveTool() {
 		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(tool, (exchange, args) -> new CallToolResult(List.of(), false))
+			.toolCall(tool, (exchange, args) -> new CallToolResult(List.of(), false))
 			.build();
 
 		assertThatCode(() -> mcpSyncServer.removeTool(TEST_TOOL_NAME)).doesNotThrowAnyException();
diff --git a/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java b/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
index 02ad955b9..38ed6525b 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
@@ -268,18 +268,18 @@ private McpServerSession.NotificationHandler asyncRootsListChangedNotificationHa
 	// ---------------------------------------
 
 	/**
-	 * Add a new tool specification at runtime.
-	 * @param toolSpecification The tool specification to add
+	 * Add a new tool call specification at runtime.
+	 * @param toolCallSpecification The tool specification to add
 	 * @return Mono that completes when clients have been notified of the change
 	 */
-	public Mono<Void> addTool(McpServerFeatures.AsyncToolSpecification toolSpecification) {
-		if (toolSpecification == null) {
+	public Mono<Void> addTool(McpServerFeatures.AsyncToolSpecification toolCallSpecification) {
+		if (toolCallSpecification == null) {
 			return Mono.error(new McpError("Tool specification must not be null"));
 		}
-		if (toolSpecification.tool() == null) {
+		if (toolCallSpecification.tool() == null) {
 			return Mono.error(new McpError("Tool must not be null"));
 		}
-		if (toolSpecification.call() == null) {
+		if (toolCallSpecification.call() == null && toolCallSpecification.callTool() == null) {
 			return Mono.error(new McpError("Tool call handler must not be null"));
 		}
 		if (this.serverCapabilities.tools() == null) {
@@ -288,13 +288,13 @@ public Mono<Void> addTool(McpServerFeatures.AsyncToolSpecification toolSpecifica
 
 		return Mono.defer(() -> {
 			// Check for duplicate tool names
-			if (this.tools.stream().anyMatch(th -> th.tool().name().equals(toolSpecification.tool().name()))) {
+			if (this.tools.stream().anyMatch(th -> th.tool().name().equals(toolCallSpecification.tool().name()))) {
 				return Mono
-					.error(new McpError("Tool with name '" + toolSpecification.tool().name() + "' already exists"));
+					.error(new McpError("Tool with name '" + toolCallSpecification.tool().name() + "' already exists"));
 			}
 
-			this.tools.add(toolSpecification);
-			logger.debug("Added tool handler: {}", toolSpecification.tool().name());
+			this.tools.add(toolCallSpecification);
+			logger.debug("Added tool handler: {}", toolCallSpecification.tool().name());
 
 			if (this.serverCapabilities.tools().listChanged()) {
 				return notifyToolsListChanged();
@@ -360,7 +360,7 @@ private McpServerSession.RequestHandler<CallToolResult> toolsCallRequestHandler(
 				return Mono.error(new McpError("Tool not found: " + callToolRequest.name()));
 			}
 
-			return toolSpecification.map(tool -> tool.call().apply(exchange, callToolRequest.arguments()))
+			return toolSpecification.map(tool -> tool.callTool().apply(exchange, callToolRequest))
 				.orElse(Mono.error(new McpError("Tool not found: " + callToolRequest.name())));
 		};
 	}
diff --git a/mcp/src/main/java/io/modelcontextprotocol/server/McpServer.java b/mcp/src/main/java/io/modelcontextprotocol/server/McpServer.java
index d6ec2cc30..7c88e12d1 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/server/McpServer.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/server/McpServer.java
@@ -82,12 +82,16 @@
  *     .capabilities(new ServerCapabilities(...))
  *     // Register tools
  *     .tools(
- *         new McpServerFeatures.AsyncToolSpecification(calculatorTool,
- *             (exchange, args) -> Mono.fromSupplier(() -> calculate(args))
- *                 .map(result -> new CallToolResult("Result: " + result))),
- *         new McpServerFeatures.AsyncToolSpecification(weatherTool,
- *             (exchange, args) -> Mono.fromSupplier(() -> getWeather(args))
- *                 .map(result -> new CallToolResult("Weather: " + result)))
+ *         McpServerFeatures.AsyncToolSpecification.builder()
+ * 			.tool(calculatorTool)
+ *   	    .callTool((exchange, args) -> Mono.fromSupplier(() -> calculate(args.arguments()))
+ *                 .map(result -> new CallToolResult("Result: " + result))))
+ *.         .build(),
+ *         McpServerFeatures.AsyncToolSpecification.builder()
+ * 	        .tool((weatherTool)
+ *          .callTool((exchange, args) -> Mono.fromSupplier(() -> getWeather(args.arguments()))
+ *                 .map(result -> new CallToolResult("Weather: " + result))))
+ *          .build()
  *     )
  *     // Register resources
  *     .resources(
@@ -321,17 +325,46 @@ public AsyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabi
 		 * map of arguments passed to the tool.
 		 * @return This builder instance for method chaining
 		 * @throws IllegalArgumentException if tool or handler is null
+		 * @deprecated Use {@link #toolCall(McpSchema.Tool, BiFunction)} instead for tool
+		 * calls that require a request object.
 		 */
+		@Deprecated
 		public AsyncSpecification tool(McpSchema.Tool tool,
 				BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<CallToolResult>> handler) {
 			Assert.notNull(tool, "Tool must not be null");
 			Assert.notNull(handler, "Handler must not be null");
+			assertNoDuplicateTool(tool.name());
 
 			this.tools.add(new McpServerFeatures.AsyncToolSpecification(tool, handler));
 
 			return this;
 		}
 
+		/**
+		 * Adds a single tool with its implementation handler to the server. This is a
+		 * convenience method for registering individual tools without creating a
+		 * {@link McpServerFeatures.AsyncToolCallSpecification} explicitly.
+		 * @param tool The tool definition including name, description, and schema. Must
+		 * not be null.
+		 * @param handler The function that implements the tool's logic. Must not be null.
+		 * The function's first argument is an {@link McpAsyncServerExchange} upon which
+		 * the server can interact with the connected client. The second argument is the
+		 * {@link McpSchema.CallToolRequest} object containing the tool call
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if tool or handler is null
+		 */
+		public AsyncSpecification toolCall(McpSchema.Tool tool,
+				BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<CallToolResult>> handler) {
+
+			Assert.notNull(tool, "Tool must not be null");
+			Assert.notNull(handler, "Handler must not be null");
+			assertNoDuplicateTool(tool.name());
+
+			this.tools.add(McpServerFeatures.AsyncToolSpecification.builder().tool(tool).callTool(handler).build());
+
+			return this;
+		}
+
 		/**
 		 * Adds multiple tools with their handlers to the server using a List. This method
 		 * is useful when tools are dynamically generated or loaded from a configuration
@@ -344,7 +377,12 @@ public AsyncSpecification tool(McpSchema.Tool tool,
 		 */
 		public AsyncSpecification tools(List<McpServerFeatures.AsyncToolSpecification> toolSpecifications) {
 			Assert.notNull(toolSpecifications, "Tool handlers list must not be null");
-			this.tools.addAll(toolSpecifications);
+
+			for (var tool : toolSpecifications) {
+				assertNoDuplicateTool(tool.tool().name());
+				this.tools.add(tool);
+			}
+
 			return this;
 		}
 
@@ -355,24 +393,31 @@ public AsyncSpecification tools(List<McpServerFeatures.AsyncToolSpecification> t
 		 * <p>
 		 * Example usage: <pre>{@code
 		 * .tools(
-		 *     new McpServerFeatures.AsyncToolSpecification(calculatorTool, calculatorHandler),
-		 *     new McpServerFeatures.AsyncToolSpecification(weatherTool, weatherHandler),
-		 *     new McpServerFeatures.AsyncToolSpecification(fileManagerTool, fileManagerHandler)
+		 *     McpServerFeatures.AsyncToolSpecification.builder().tool(calculatorTool).callTool(calculatorHandler).build(),
+		 *     McpServerFeatures.AsyncToolSpecification.builder().tool(weatherTool).callTool(weatherHandler).build(),
+		 *     McpServerFeatures.AsyncToolSpecification.builder().tool(fileManagerTool).callTool(fileManagerHandler).build()
 		 * )
 		 * }</pre>
 		 * @param toolSpecifications The tool specifications to add. Must not be null.
 		 * @return This builder instance for method chaining
 		 * @throws IllegalArgumentException if toolSpecifications is null
-		 * @see #tools(List)
 		 */
 		public AsyncSpecification tools(McpServerFeatures.AsyncToolSpecification... toolSpecifications) {
 			Assert.notNull(toolSpecifications, "Tool handlers list must not be null");
+
 			for (McpServerFeatures.AsyncToolSpecification tool : toolSpecifications) {
+				assertNoDuplicateTool(tool.tool().name());
 				this.tools.add(tool);
 			}
 			return this;
 		}
 
+		private void assertNoDuplicateTool(String toolName) {
+			if (this.tools.stream().anyMatch(toolSpec -> toolSpec.tool().name().equals(toolName))) {
+				throw new IllegalArgumentException("Tool with name '" + toolName + "' is already registered.");
+			}
+		}
+
 		/**
 		 * Registers multiple resources with their handlers using a Map. This method is
 		 * useful when resources are dynamically generated or loaded from a configuration
@@ -812,17 +857,45 @@ public SyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabil
 		 * list of arguments passed to the tool.
 		 * @return This builder instance for method chaining
 		 * @throws IllegalArgumentException if tool or handler is null
+		 * @deprecated Use {@link #toolCall(McpSchema.Tool, BiFunction)} instead for tool
+		 * calls that require a request object.
 		 */
+		@Deprecated
 		public SyncSpecification tool(McpSchema.Tool tool,
 				BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> handler) {
 			Assert.notNull(tool, "Tool must not be null");
 			Assert.notNull(handler, "Handler must not be null");
+			assertNoDuplicateTool(tool.name());
 
 			this.tools.add(new McpServerFeatures.SyncToolSpecification(tool, handler));
 
 			return this;
 		}
 
+		/**
+		 * Adds a single tool with its implementation handler to the server. This is a
+		 * convenience method for registering individual tools without creating a
+		 * {@link McpServerFeatures.SyncToolSpecification} explicitly.
+		 * @param tool The tool definition including name, description, and schema. Must
+		 * not be null.
+		 * @param handler The function that implements the tool's logic. Must not be null.
+		 * The function's first argument is an {@link McpSyncServerExchange} upon which
+		 * the server can interact with the connected client. The second argument is the
+		 * list of arguments passed to the tool.
+		 * @return This builder instance for method chaining
+		 * @throws IllegalArgumentException if tool or handler is null
+		 */
+		public SyncSpecification toolCall(McpSchema.Tool tool,
+				BiFunction<McpSyncServerExchange, McpSchema.CallToolRequest, McpSchema.CallToolResult> handler) {
+			Assert.notNull(tool, "Tool must not be null");
+			Assert.notNull(handler, "Handler must not be null");
+			assertNoDuplicateTool(tool.name());
+
+			this.tools.add(new McpServerFeatures.SyncToolSpecification(tool, null, handler));
+
+			return this;
+		}
+
 		/**
 		 * Adds multiple tools with their handlers to the server using a List. This method
 		 * is useful when tools are dynamically generated or loaded from a configuration
@@ -835,7 +908,13 @@ public SyncSpecification tool(McpSchema.Tool tool,
 		 */
 		public SyncSpecification tools(List<McpServerFeatures.SyncToolSpecification> toolSpecifications) {
 			Assert.notNull(toolSpecifications, "Tool handlers list must not be null");
-			this.tools.addAll(toolSpecifications);
+
+			for (var tool : toolSpecifications) {
+				String toolName = tool.tool().name();
+				assertNoDuplicateTool(toolName); // Check against existing tools
+				this.tools.add(tool);
+			}
+
 			return this;
 		}
 
@@ -858,12 +937,20 @@ public SyncSpecification tools(List<McpServerFeatures.SyncToolSpecification> too
 		 */
 		public SyncSpecification tools(McpServerFeatures.SyncToolSpecification... toolSpecifications) {
 			Assert.notNull(toolSpecifications, "Tool handlers list must not be null");
+
 			for (McpServerFeatures.SyncToolSpecification tool : toolSpecifications) {
+				assertNoDuplicateTool(tool.tool().name());
 				this.tools.add(tool);
 			}
 			return this;
 		}
 
+		private void assertNoDuplicateTool(String toolName) {
+			if (this.tools.stream().anyMatch(toolSpec -> toolSpec.tool().name().equals(toolName))) {
+				throw new IllegalArgumentException("Tool with name '" + toolName + "' is already registered.");
+			}
+		}
+
 		/**
 		 * Registers multiple resources with their handlers using a Map. This method is
 		 * useful when resources are dynamically generated or loaded from a configuration
diff --git a/mcp/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java b/mcp/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
index 8311f5d41..b818f0b7e 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
@@ -12,6 +12,7 @@
 import java.util.function.BiFunction;
 
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.McpSchema.CallToolRequest;
 import io.modelcontextprotocol.util.Assert;
 import io.modelcontextprotocol.util.Utils;
 import reactor.core.publisher.Mono;
@@ -203,52 +204,99 @@ record Sync(McpSchema.Implementation serverInfo, McpSchema.ServerCapabilities se
 	/**
 	 * Specification of a tool with its asynchronous handler function. Tools are the
 	 * primary way for MCP servers to expose functionality to AI models. Each tool
-	 * represents a specific capability, such as:
-	 * <ul>
-	 * <li>Performing calculations
-	 * <li>Accessing external APIs
-	 * <li>Querying databases
-	 * <li>Manipulating files
-	 * <li>Executing system commands
-	 * </ul>
-	 *
-	 * <p>
-	 * Example tool specification: <pre>{@code
-	 * new McpServerFeatures.AsyncToolSpecification(
-	 *     new Tool(
-	 *         "calculator",
-	 *         "Performs mathematical calculations",
-	 *         new JsonSchemaObject()
-	 *             .required("expression")
-	 *             .property("expression", JsonSchemaType.STRING)
-	 *     ),
-	 *     (exchange, args) -> {
-	 *         String expr = (String) args.get("expression");
-	 *         return Mono.fromSupplier(() -> evaluate(expr))
-	 *             .map(result -> new CallToolResult("Result: " + result));
-	 *     }
-	 * )
-	 * }</pre>
+	 * represents a specific capability.
 	 *
 	 * @param tool The tool definition including name, description, and parameter schema
-	 * @param call The function that implements the tool's logic, receiving arguments and
-	 * returning results. The function's first argument is an
-	 * {@link McpAsyncServerExchange} upon which the server can interact with the
-	 * connected client. The second arguments is a map of tool arguments.
+	 * @param call Deprecated. Uset he {@link AsyncToolCallSpecification#callTool}
+	 * instead.
+	 * @param callTool The function that implements the tool's logic, receiving a
+	 * {@link McpAsyncServerExchange} and a
+	 * {@link io.modelcontextprotocol.spec.McpSchema.CallToolRequest} and returning
+	 * results. The function's first argument is an {@link McpAsyncServerExchange} upon
+	 * which the server can interact with the connected client. The second arguments is a
+	 * map of tool arguments.
 	 */
 	public record AsyncToolSpecification(McpSchema.Tool tool,
-			BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call) {
+			@Deprecated BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call,
+			BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> callTool) {
 
-		static AsyncToolSpecification fromSync(SyncToolSpecification tool) {
+		/**
+		 * @deprecated Use {@link #AsyncToolSpecification(McpSchema.Tool, null,
+		 * BiFunction)} instead.
+		 **/
+		@Deprecated
+		public AsyncToolSpecification(McpSchema.Tool tool,
+				BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call) {
+			this(tool, call, (exchange, toolReq) -> call.apply(exchange, toolReq.arguments()));
+		}
+
+		static AsyncToolSpecification fromSync(SyncToolSpecification syncToolSpec) {
 			// FIXME: This is temporary, proper validation should be implemented
-			if (tool == null) {
+			if (syncToolSpec == null) {
 				return null;
 			}
-			return new AsyncToolSpecification(tool.tool(),
-					(exchange, map) -> Mono
-						.fromCallable(() -> tool.call().apply(new McpSyncServerExchange(exchange), map))
+
+			return new AsyncToolSpecification(syncToolSpec.tool(),
+					(syncToolSpec.call() != null) ? (exchange, map) -> Mono
+						.fromCallable(() -> syncToolSpec.call().apply(new McpSyncServerExchange(exchange), map))
+						.subscribeOn(Schedulers.boundedElastic()) : null,
+					(exchange, req) -> Mono
+						.fromCallable(() -> syncToolSpec.callTool().apply(new McpSyncServerExchange(exchange), req))
 						.subscribeOn(Schedulers.boundedElastic()));
 		}
+
+		/**
+		 * Builder for creating AsyncToolSpecification instances.
+		 */
+		public static class Builder {
+
+			private McpSchema.Tool tool;
+
+			private BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> callTool;
+
+			/**
+			 * Sets the tool definition.
+			 * @param tool The tool definition including name, description, and parameter
+			 * schema
+			 * @return this builder instance
+			 */
+			public Builder tool(McpSchema.Tool tool) {
+				this.tool = tool;
+				return this;
+			}
+
+			/**
+			 * Sets the call tool handler function.
+			 * @param callTool The function that implements the tool's logic
+			 * @return this builder instance
+			 */
+			public Builder callTool(
+					BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> callTool) {
+				this.callTool = callTool;
+				return this;
+			}
+
+			/**
+			 * Builds the AsyncToolSpecification instance.
+			 * @return a new AsyncToolSpecification instance
+			 * @throws IllegalArgumentException if required fields are not set
+			 */
+			public AsyncToolSpecification build() {
+				Assert.notNull(tool, "Tool must not be null");
+				Assert.notNull(callTool, "CallTool function must not be null");
+
+				return new AsyncToolSpecification(tool, null, callTool);
+			}
+
+		}
+
+		/**
+		 * Creates a new builder instance.
+		 * @return a new Builder instance
+		 */
+		public static Builder builder() {
+			return new Builder();
+		}
 	}
 
 	/**
@@ -263,13 +311,13 @@ static AsyncToolSpecification fromSync(SyncToolSpecification tool) {
 	 * </ul>
 	 *
 	 * <p>
-	 * Example resource specification: <pre>{@code
+	 * Example resource specification:
+	 *
+	 * <pre>{@code
 	 * new McpServerFeatures.AsyncResourceSpecification(
-	 *     new Resource("docs", "Documentation files", "text/markdown"),
-	 *     (exchange, request) ->
-	 *         Mono.fromSupplier(() -> readFile(request.getPath()))
-	 *             .map(ReadResourceResult::new)
-	 * )
+	 * 		new Resource("docs", "Documentation files", "text/markdown"),
+	 * 		(exchange, request) -> Mono.fromSupplier(() -> readFile(request.getPath()))
+	 * 				.map(ReadResourceResult::new))
 	 * }</pre>
 	 *
 	 * @param resource The resource definition including name, description, and MIME type
@@ -305,16 +353,16 @@ static AsyncResourceSpecification fromSync(SyncResourceSpecification resource) {
 	 * </ul>
 	 *
 	 * <p>
-	 * Example prompt specification: <pre>{@code
+	 * Example prompt specification:
+	 *
+	 * <pre>{@code
 	 * new McpServerFeatures.AsyncPromptSpecification(
-	 *     new Prompt("analyze", "Code analysis template"),
-	 *     (exchange, request) -> {
-	 *         String code = request.getArguments().get("code");
-	 *         return Mono.just(new GetPromptResult(
-	 *             "Analyze this code:\n\n" + code + "\n\nProvide feedback on:"
-	 *         ));
-	 *     }
-	 * )
+	 * 		new Prompt("analyze", "Code analysis template"),
+	 * 		(exchange, request) -> {
+	 * 			String code = request.getArguments().get("code");
+	 * 			return Mono.just(new GetPromptResult(
+	 * 					"Analyze this code:\n\n" + code + "\n\nProvide feedback on:"));
+	 * 		})
 	 * }</pre>
 	 *
 	 * @param prompt The prompt definition including name and description
@@ -379,41 +427,99 @@ static AsyncCompletionSpecification fromSync(SyncCompletionSpecification complet
 
 	/**
 	 * Specification of a tool with its synchronous handler function. Tools are the
-	 * primary way for MCP servers to expose functionality to AI models. Each tool
-	 * represents a specific capability, such as:
-	 * <ul>
-	 * <li>Performing calculations
-	 * <li>Accessing external APIs
-	 * <li>Querying databases
-	 * <li>Manipulating files
-	 * <li>Executing system commands
-	 * </ul>
+	 * primary way for MCP servers to expose functionality to AI models.
 	 *
 	 * <p>
-	 * Example tool specification: <pre>{@code
-	 * new McpServerFeatures.SyncToolSpecification(
-	 *     new Tool(
-	 *         "calculator",
-	 *         "Performs mathematical calculations",
-	 *         new JsonSchemaObject()
-	 *             .required("expression")
-	 *             .property("expression", JsonSchemaType.STRING)
-	 *     ),
-	 *     (exchange, args) -> {
-	 *         String expr = (String) args.get("expression");
-	 *         return new CallToolResult("Result: " + evaluate(expr));
-	 *     }
-	 * )
+	 * Example tool specification:
+	 *
+	 * <pre>{@code
+	 * McpServerFeatures.SyncToolSpecification.builder()
+	 * 		.tool(new Tool(
+	 * 				"calculator",
+	 * 				"Performs mathematical calculations",
+	 * 				new JsonSchemaObject()
+	 * 						.required("expression")
+	 * 						.property("expression", JsonSchemaType.STRING)))
+	 * 		.toolCall((exchange, req) -> {
+	 * 			String expr = (String) req.arguments().get("expression");
+	 * 			return new CallToolResult("Result: " + evaluate(expr));
+	 * 		}))
+	 *      .build();
 	 * }</pre>
 	 *
 	 * @param tool The tool definition including name, description, and parameter schema
-	 * @param call The function that implements the tool's logic, receiving arguments and
-	 * returning results. The function's first argument is an
+	 * @param (deprecated) call The function that implements the tool's logic, receiving
+	 * arguments and returning results. The function's first argument is an
 	 * {@link McpSyncServerExchange} upon which the server can interact with the connected
-	 * client. The second arguments is a map of arguments passed to the tool.
+	 * @param callTool The function that implements the tool's logic, receiving a
+	 * {@link McpSyncServerExchange} and a
+	 * {@link io.modelcontextprotocol.spec.McpSchema.CallToolRequest} and returning
+	 * results. The function's first argument is an {@link McpSyncServerExchange} upon
+	 * which the server can interact with the client. The second arguments is a map of
+	 * arguments passed to the tool.
 	 */
 	public record SyncToolSpecification(McpSchema.Tool tool,
-			BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call) {
+			@Deprecated BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call,
+			BiFunction<McpSyncServerExchange, CallToolRequest, McpSchema.CallToolResult> callTool) {
+
+		@Deprecated
+		public SyncToolSpecification(McpSchema.Tool tool,
+				BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call) {
+			this(tool, call, (exchange, toolReq) -> call.apply(exchange, toolReq.arguments()));
+		}
+
+		/**
+		 * Builder for creating SyncToolSpecification instances.
+		 */
+		public static class Builder {
+
+			private McpSchema.Tool tool;
+
+			private BiFunction<McpSyncServerExchange, CallToolRequest, McpSchema.CallToolResult> callTool;
+
+			/**
+			 * Sets the tool definition.
+			 * @param tool The tool definition including name, description, and parameter
+			 * schema
+			 * @return this builder instance
+			 */
+			public Builder tool(McpSchema.Tool tool) {
+				this.tool = tool;
+				return this;
+			}
+
+			/**
+			 * Sets the call tool handler function.
+			 * @param callTool The function that implements the tool's logic
+			 * @return this builder instance
+			 */
+			public Builder callTool(
+					BiFunction<McpSyncServerExchange, CallToolRequest, McpSchema.CallToolResult> callTool) {
+				this.callTool = callTool;
+				return this;
+			}
+
+			/**
+			 * Builds the SyncToolSpecification instance.
+			 * @return a new SyncToolSpecification instance
+			 * @throws IllegalArgumentException if required fields are not set
+			 */
+			public SyncToolSpecification build() {
+				Assert.notNull(tool, "Tool must not be null");
+				Assert.notNull(callTool, "CallTool function must not be null");
+
+				return new SyncToolSpecification(tool, null, callTool);
+			}
+
+		}
+
+		/**
+		 * Creates a new builder instance.
+		 * @return a new Builder instance
+		 */
+		public static Builder builder() {
+			return new Builder();
+		}
 	}
 
 	/**
@@ -428,14 +534,15 @@ public record SyncToolSpecification(McpSchema.Tool tool,
 	 * </ul>
 	 *
 	 * <p>
-	 * Example resource specification: <pre>{@code
+	 * Example resource specification:
+	 *
+	 * <pre>{@code
 	 * new McpServerFeatures.SyncResourceSpecification(
-	 *     new Resource("docs", "Documentation files", "text/markdown"),
-	 *     (exchange, request) -> {
-	 *         String content = readFile(request.getPath());
-	 *         return new ReadResourceResult(content);
-	 *     }
-	 * )
+	 * 		new Resource("docs", "Documentation files", "text/markdown"),
+	 * 		(exchange, request) -> {
+	 * 			String content = readFile(request.getPath());
+	 * 			return new ReadResourceResult(content);
+	 * 		})
 	 * }</pre>
 	 *
 	 * @param resource The resource definition including name, description, and MIME type
@@ -460,16 +567,16 @@ public record SyncResourceSpecification(McpSchema.Resource resource,
 	 * </ul>
 	 *
 	 * <p>
-	 * Example prompt specification: <pre>{@code
+	 * Example prompt specification:
+	 *
+	 * <pre>{@code
 	 * new McpServerFeatures.SyncPromptSpecification(
-	 *     new Prompt("analyze", "Code analysis template"),
-	 *     (exchange, request) -> {
-	 *         String code = request.getArguments().get("code");
-	 *         return new GetPromptResult(
-	 *             "Analyze this code:\n\n" + code + "\n\nProvide feedback on:"
-	 *         );
-	 *     }
-	 * )
+	 * 		new Prompt("analyze", "Code analysis template"),
+	 * 		(exchange, request) -> {
+	 * 			String code = request.getArguments().get("code");
+	 * 			return new GetPromptResult(
+	 * 					"Analyze this code:\n\n" + code + "\n\nProvide feedback on:");
+	 * 		})
 	 * }</pre>
 	 *
 	 * @param prompt The prompt definition including name and description
diff --git a/mcp/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java b/mcp/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
index 91f8d9e4c..92bc03f8c 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
@@ -4,6 +4,7 @@
 
 package io.modelcontextprotocol.server;
 
+import io.modelcontextprotocol.server.McpServerFeatures.AsyncToolSpecification;
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpSchema.LoggingMessageNotification;
 import io.modelcontextprotocol.util.Assert;
@@ -68,7 +69,7 @@ public McpSyncServer(McpAsyncServer asyncServer) {
 	 * @param toolHandler The tool handler to add
 	 */
 	public void addTool(McpServerFeatures.SyncToolSpecification toolHandler) {
-		this.asyncServer.addTool(McpServerFeatures.AsyncToolSpecification.fromSync(toolHandler)).block();
+		this.asyncServer.addTool(AsyncToolSpecification.fromSync(toolHandler)).block();
 	}
 
 	/**
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java b/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
index dd9f65895..c523d1179 100644
--- a/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
+++ b/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
@@ -30,10 +30,11 @@
 
 /**
  * Test suite for the {@link McpAsyncServer} that can be used with different
- * {@link McpTransportProvider} implementations.
+ * {@link io.modelcontextprotocol.spec.McpServerTransportProvider} implementations.
  *
  * @author Christian Tzolov
  */
+// KEEP IN SYNC with the class in mcp-test module
 public abstract class AbstractMcpAsyncServerTests {
 
 	private static final String TEST_TOOL_NAME = "test-tool";
@@ -101,6 +102,7 @@ void testImmediateClose() {
 			""";
 
 	@Test
+	@Deprecated
 	void testAddTool() {
 		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
@@ -116,6 +118,23 @@ void testAddTool() {
 	}
 
 	@Test
+	void testAddToolCall() {
+		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
+		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.build();
+
+		StepVerifier.create(mcpAsyncServer.addTool(McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(newTool)
+			.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build())).verifyComplete();
+
+		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	@Deprecated
 	void testAddDuplicateTool() {
 		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
 
@@ -136,6 +155,83 @@ void testAddDuplicateTool() {
 		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
 	}
 
+	@Test
+	void testAddDuplicateToolCall() {
+		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
+
+		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build();
+
+		StepVerifier.create(mcpAsyncServer.addTool(McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(duplicateTool)
+			.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build())).verifyErrorSatisfies(error -> {
+				assertThat(error).isInstanceOf(McpError.class)
+					.hasMessage("Tool with name '" + TEST_TOOL_NAME + "' already exists");
+			});
+
+		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testDuplicateToolCallDuringBuilding() {
+		Tool duplicateTool = new Tool("duplicate-build-toolcall", "Duplicate toolcall during building",
+				emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(duplicateTool, (exchange, request) -> Mono.just(new CallToolResult(List.of(), false))) // Duplicate!
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'duplicate-build-toolcall' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchListRegistration() {
+		Tool duplicateTool = new Tool("batch-list-tool", "Duplicate tool in batch list", emptyJsonSchema);
+		List<McpServerFeatures.AsyncToolSpecification> specs = List.of(
+				McpServerFeatures.AsyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+					.build(),
+				McpServerFeatures.AsyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+					.build() // Duplicate!
+		);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(specs)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-list-tool' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchVarargsRegistration() {
+		Tool duplicateTool = new Tool("batch-varargs-tool", "Duplicate tool in batch varargs", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.async(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(McpServerFeatures.AsyncToolSpecification.builder()
+				.tool(duplicateTool)
+				.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+				.build(),
+					McpServerFeatures.AsyncToolSpecification.builder()
+						.tool(duplicateTool)
+						.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+						.build() // Duplicate!
+			)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-varargs-tool' is already registered.");
+	}
+
 	@Test
 	void testRemoveTool() {
 		Tool too = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
@@ -143,7 +239,7 @@ void testRemoveTool() {
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
 			.build();
 
 		StepVerifier.create(mcpAsyncServer.removeTool(TEST_TOOL_NAME)).verifyComplete();
@@ -172,7 +268,7 @@ void testNotifyToolsListChanged() {
 		var mcpAsyncServer = McpServer.async(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
+			.toolCall(too, (exchange, args) -> Mono.just(new CallToolResult(List.of(), false)))
 			.build();
 
 		StepVerifier.create(mcpAsyncServer.notifyToolsListChanged()).verifyComplete();
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java b/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
index 6cbb8632c..018b547cb 100644
--- a/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
+++ b/mcp/src/test/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
@@ -4,8 +4,16 @@
 
 package io.modelcontextprotocol.server;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 import java.util.List;
 
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
 import io.modelcontextprotocol.spec.McpError;
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
@@ -17,13 +25,6 @@
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.Tool;
 import io.modelcontextprotocol.spec.McpServerTransportProvider;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatCode;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * Test suite for the {@link McpSyncServer} that can be used with different
@@ -31,6 +32,7 @@
  *
  * @author Christian Tzolov
  */
+// KEEP IN SYNC with the class in mcp-test module
 public abstract class AbstractMcpSyncServerTests {
 
 	private static final String TEST_TOOL_NAME = "test-tool";
@@ -108,6 +110,7 @@ void testGetAsyncServer() {
 			""";
 
 	@Test
+	@Deprecated
 	void testAddTool() {
 		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
@@ -123,6 +126,23 @@ void testAddTool() {
 	}
 
 	@Test
+	void testAddToolCall() {
+		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.build();
+
+		Tool newTool = new McpSchema.Tool("new-tool", "New test tool", emptyJsonSchema);
+		assertThatCode(() -> mcpSyncServer.addTool(McpServerFeatures.SyncToolSpecification.builder()
+			.tool(newTool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+			.build())).doesNotThrowAnyException();
+
+		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	@Deprecated
 	void testAddDuplicateTool() {
 		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
 
@@ -140,6 +160,81 @@ void testAddDuplicateTool() {
 		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
 	}
 
+	@Test
+	void testAddDuplicateToolCall() {
+		Tool duplicateTool = new McpSchema.Tool(TEST_TOOL_NAME, "Duplicate tool", emptyJsonSchema);
+
+		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false))
+			.build();
+
+		assertThatThrownBy(() -> mcpSyncServer.addTool(McpServerFeatures.SyncToolSpecification.builder()
+			.tool(duplicateTool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+			.build())).isInstanceOf(McpError.class)
+			.hasMessage("Tool with name '" + TEST_TOOL_NAME + "' already exists");
+
+		assertThatCode(() -> mcpSyncServer.closeGracefully()).doesNotThrowAnyException();
+	}
+
+	@Test
+	void testDuplicateToolCallDuringBuilding() {
+		Tool duplicateTool = new Tool("duplicate-build-toolcall", "Duplicate toolcall during building",
+				emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false))
+			.toolCall(duplicateTool, (exchange, request) -> new CallToolResult(List.of(), false)) // Duplicate!
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'duplicate-build-toolcall' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchListRegistration() {
+		Tool duplicateTool = new Tool("batch-list-tool", "Duplicate tool in batch list", emptyJsonSchema);
+		List<McpServerFeatures.SyncToolSpecification> specs = List.of(
+				McpServerFeatures.SyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+					.build(),
+				McpServerFeatures.SyncToolSpecification.builder()
+					.tool(duplicateTool)
+					.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+					.build() // Duplicate!
+		);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(specs)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-list-tool' is already registered.");
+	}
+
+	@Test
+	void testDuplicateToolsInBatchVarargsRegistration() {
+		Tool duplicateTool = new Tool("batch-varargs-tool", "Duplicate tool in batch varargs", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServer.sync(createMcpTransportProvider())
+			.serverInfo("test-server", "1.0.0")
+			.capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(McpServerFeatures.SyncToolSpecification.builder()
+				.tool(duplicateTool)
+				.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+				.build(),
+					McpServerFeatures.SyncToolSpecification.builder()
+						.tool(duplicateTool)
+						.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+						.build() // Duplicate!
+			)
+			.build()).isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Tool with name 'batch-varargs-tool' is already registered.");
+	}
+
 	@Test
 	void testRemoveTool() {
 		Tool tool = new McpSchema.Tool(TEST_TOOL_NAME, "Test tool", emptyJsonSchema);
@@ -147,7 +242,7 @@ void testRemoveTool() {
 		var mcpSyncServer = McpServer.sync(createMcpTransportProvider())
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(tool, (exchange, args) -> new CallToolResult(List.of(), false))
+			.toolCall(tool, (exchange, args) -> new CallToolResult(List.of(), false))
 			.build();
 
 		assertThatCode(() -> mcpSyncServer.removeTool(TEST_TOOL_NAME)).doesNotThrowAnyException();
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java b/mcp/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java
new file mode 100644
index 000000000..8997c8f42
--- /dev/null
+++ b/mcp/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java
@@ -0,0 +1,229 @@
+/*
+ * Copyright 2024-2024 the original author or authors.
+ */
+
+package io.modelcontextprotocol.server;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import io.modelcontextprotocol.spec.McpSchema.CallToolRequest;
+import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
+import io.modelcontextprotocol.spec.McpSchema.TextContent;
+import io.modelcontextprotocol.spec.McpSchema.Tool;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+/**
+ * Tests for {@link McpServerFeatures.AsyncToolSpecification.Builder}.
+ *
+ * @author Christian Tzolov
+ */
+class AsyncToolSpecificationBuilderTest {
+
+	String emptyJsonSchema = """
+			{
+				"type": "object"
+			}
+			""";
+
+	@Test
+	void builderShouldCreateValidAsyncToolSpecification() {
+
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+
+		McpServerFeatures.AsyncToolSpecification specification = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(tool)
+			.callTool((exchange, request) -> Mono
+				.just(new CallToolResult(List.of(new TextContent("Test result")), false)))
+			.build();
+
+		assertThat(specification).isNotNull();
+		assertThat(specification.tool()).isEqualTo(tool);
+		assertThat(specification.callTool()).isNotNull();
+		assertThat(specification.call()).isNull(); // deprecated field should be null
+	}
+
+	@Test
+	void builderShouldThrowExceptionWhenToolIsNull() {
+		assertThatThrownBy(() -> McpServerFeatures.AsyncToolSpecification.builder()
+			.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false)))
+			.build()).isInstanceOf(IllegalArgumentException.class).hasMessage("Tool must not be null");
+	}
+
+	@Test
+	void builderShouldThrowExceptionWhenCallToolIsNull() {
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServerFeatures.AsyncToolSpecification.builder().tool(tool).build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("CallTool function must not be null");
+	}
+
+	@Test
+	void builderShouldAllowMethodChaining() {
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+		McpServerFeatures.AsyncToolSpecification.Builder builder = McpServerFeatures.AsyncToolSpecification.builder();
+
+		// Then - verify method chaining returns the same builder instance
+		assertThat(builder.tool(tool)).isSameAs(builder);
+		assertThat(builder.callTool((exchange, request) -> Mono.just(new CallToolResult(List.of(), false))))
+			.isSameAs(builder);
+	}
+
+	@Test
+	void builtSpecificationShouldExecuteCallToolCorrectly() {
+		Tool tool = new Tool("calculator", "Simple calculator", emptyJsonSchema);
+		String expectedResult = "42";
+
+		McpServerFeatures.AsyncToolSpecification specification = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(tool)
+			.callTool((exchange, request) -> {
+				return Mono.just(new CallToolResult(List.of(new TextContent(expectedResult)), false));
+			})
+			.build();
+
+		CallToolRequest request = new CallToolRequest("calculator", Map.of());
+		Mono<CallToolResult> resultMono = specification.callTool().apply(null, request);
+
+		StepVerifier.create(resultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+	}
+
+	@Test
+	@SuppressWarnings("deprecation")
+	void deprecatedConstructorShouldWorkCorrectly() {
+		Tool tool = new Tool("deprecated-tool", "A deprecated tool", emptyJsonSchema);
+		String expectedResult = "deprecated result";
+
+		// Test the deprecated constructor that takes a 'call' function
+		McpServerFeatures.AsyncToolSpecification specification = new McpServerFeatures.AsyncToolSpecification(tool,
+				(exchange, arguments) -> Mono
+					.just(new CallToolResult(List.of(new TextContent(expectedResult)), false)));
+
+		assertThat(specification).isNotNull();
+		assertThat(specification.tool()).isEqualTo(tool);
+		assertThat(specification.call()).isNotNull(); // deprecated field should be set
+		assertThat(specification.callTool()).isNotNull(); // should be automatically
+															// created
+
+		// Test that the callTool function works (it should delegate to the call function)
+		CallToolRequest request = new CallToolRequest("deprecated-tool", Map.of("arg1", "value1"));
+		Mono<CallToolResult> resultMono = specification.callTool().apply(null, request);
+
+		StepVerifier.create(resultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+
+		// Test that the deprecated call function also works directly
+		Mono<CallToolResult> callResultMono = specification.call().apply(null, request.arguments());
+
+		StepVerifier.create(callResultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+	}
+
+	@Test
+	void fromSyncShouldConvertSyncToolSpecificationCorrectly() {
+		Tool tool = new Tool("sync-tool", "A sync tool", emptyJsonSchema);
+		String expectedResult = "sync result";
+
+		// Create a sync tool specification
+		McpServerFeatures.SyncToolSpecification syncSpec = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(tool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(new TextContent(expectedResult)), false))
+			.build();
+
+		// Convert to async using fromSync
+		McpServerFeatures.AsyncToolSpecification asyncSpec = McpServerFeatures.AsyncToolSpecification
+			.fromSync(syncSpec);
+
+		assertThat(asyncSpec).isNotNull();
+		assertThat(asyncSpec.tool()).isEqualTo(tool);
+		assertThat(asyncSpec.callTool()).isNotNull();
+		assertThat(asyncSpec.call()).isNull(); // should be null since sync spec doesn't
+												// have deprecated call
+
+		// Test that the converted async specification works correctly
+		CallToolRequest request = new CallToolRequest("sync-tool", Map.of("param", "value"));
+		Mono<CallToolResult> resultMono = asyncSpec.callTool().apply(null, request);
+
+		StepVerifier.create(resultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+	}
+
+	@Test
+	@SuppressWarnings("deprecation")
+	void fromSyncShouldConvertSyncToolSpecificationWithDeprecatedCallCorrectly() {
+		Tool tool = new Tool("sync-deprecated-tool", "A sync tool with deprecated call", emptyJsonSchema);
+		String expectedResult = "sync deprecated result";
+		McpAsyncServerExchange nullExchange = null; // Mock or create a suitable exchange
+													// if needed
+
+		// Create a sync tool specification using the deprecated constructor
+		McpServerFeatures.SyncToolSpecification syncSpec = new McpServerFeatures.SyncToolSpecification(tool,
+				(exchange, arguments) -> new CallToolResult(List.of(new TextContent(expectedResult)), false));
+
+		// Convert to async using fromSync
+		McpServerFeatures.AsyncToolSpecification asyncSpec = McpServerFeatures.AsyncToolSpecification
+			.fromSync(syncSpec);
+
+		assertThat(asyncSpec).isNotNull();
+		assertThat(asyncSpec.tool()).isEqualTo(tool);
+		assertThat(asyncSpec.callTool()).isNotNull();
+		assertThat(asyncSpec.call()).isNotNull(); // should be set since sync spec has
+													// deprecated call
+
+		// Test that the converted async specification works correctly via callTool
+		CallToolRequest request = new CallToolRequest("sync-deprecated-tool", Map.of("param", "value"));
+		Mono<CallToolResult> resultMono = asyncSpec.callTool().apply(nullExchange, request);
+
+		StepVerifier.create(resultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+
+		// Test that the deprecated call function also works
+		Mono<CallToolResult> callResultMono = asyncSpec.call().apply(nullExchange, request.arguments());
+
+		StepVerifier.create(callResultMono).assertNext(result -> {
+			assertThat(result).isNotNull();
+			assertThat(result.content()).hasSize(1);
+			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+			assertThat(result.isError()).isFalse();
+		}).verifyComplete();
+	}
+
+	@Test
+	void fromSyncShouldReturnNullWhenSyncSpecIsNull() {
+		assertThat(McpServerFeatures.AsyncToolSpecification.fromSync(null)).isNull();
+	}
+
+}
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/BaseMcpAsyncServerTests.java b/mcp/src/test/java/io/modelcontextprotocol/server/BaseMcpAsyncServerTests.java
deleted file mode 100644
index 208bcb71b..000000000
--- a/mcp/src/test/java/io/modelcontextprotocol/server/BaseMcpAsyncServerTests.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package io.modelcontextprotocol.server;
-
-public abstract class BaseMcpAsyncServerTests {
-
-}
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java b/mcp/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java
new file mode 100644
index 000000000..e493de29f
--- /dev/null
+++ b/mcp/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright 2024-2024 the original author or authors.
+ */
+
+package io.modelcontextprotocol.server;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import io.modelcontextprotocol.spec.McpSchema.CallToolRequest;
+import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
+import io.modelcontextprotocol.spec.McpSchema.TextContent;
+import io.modelcontextprotocol.spec.McpSchema.Tool;
+
+/**
+ * Tests for {@link McpServerFeatures.SyncToolSpecification.Builder}.
+ *
+ * @author Christian Tzolov
+ */
+class SyncToolSpecificationBuilderTest {
+
+	String emptyJsonSchema = """
+			{
+				"type": "object"
+			}
+			""";
+
+	@Test
+	void builderShouldCreateValidSyncToolSpecification() {
+
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+
+		McpServerFeatures.SyncToolSpecification specification = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(tool)
+			.callTool((exchange, request) -> new CallToolResult(List.of(new TextContent("Test result")), false))
+			.build();
+
+		assertThat(specification).isNotNull();
+		assertThat(specification.tool()).isEqualTo(tool);
+		assertThat(specification.callTool()).isNotNull();
+		assertThat(specification.call()).isNull(); // deprecated field should be null
+	}
+
+	@Test
+	void builderShouldThrowExceptionWhenToolIsNull() {
+		assertThatThrownBy(() -> McpServerFeatures.SyncToolSpecification.builder()
+			.callTool((exchange, request) -> new CallToolResult(List.of(), false))
+			.build()).isInstanceOf(IllegalArgumentException.class).hasMessage("Tool must not be null");
+	}
+
+	@Test
+	void builderShouldThrowExceptionWhenCallToolIsNull() {
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+
+		assertThatThrownBy(() -> McpServerFeatures.SyncToolSpecification.builder().tool(tool).build())
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("CallTool function must not be null");
+	}
+
+	@Test
+	void builderShouldAllowMethodChaining() {
+		Tool tool = new Tool("test-tool", "A test tool", emptyJsonSchema);
+		McpServerFeatures.SyncToolSpecification.Builder builder = McpServerFeatures.SyncToolSpecification.builder();
+
+		// Then - verify method chaining returns the same builder instance
+		assertThat(builder.tool(tool)).isSameAs(builder);
+		assertThat(builder.callTool((exchange, request) -> new CallToolResult(List.of(), false))).isSameAs(builder);
+	}
+
+	@Test
+	void builtSpecificationShouldExecuteCallToolCorrectly() {
+		Tool tool = new Tool("calculator", "Simple calculator", emptyJsonSchema);
+		String expectedResult = "42";
+
+		McpServerFeatures.SyncToolSpecification specification = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(tool)
+			.callTool((exchange, request) -> {
+				// Simple test implementation
+				return new CallToolResult(List.of(new TextContent(expectedResult)), false);
+			})
+			.build();
+
+		CallToolRequest request = new CallToolRequest("calculator", Map.of());
+		CallToolResult result = specification.callTool().apply(null, request);
+
+		assertThat(result).isNotNull();
+		assertThat(result.content()).hasSize(1);
+		assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
+		assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
+		assertThat(result.isError()).isFalse();
+	}
+
+}
diff --git a/mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java b/mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java
index 4bd98b406..d378afc78 100644
--- a/mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java
+++ b/mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java
@@ -109,13 +109,15 @@ public void after() {
 	// @Disabled
 	void testCreateMessageWithoutSamplingCapabilities() {
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.createMessage(mock(McpSchema.CreateMessageRequest.class)).block();
+				exchange.createMessage(mock(McpSchema.CreateMessageRequest.class)).block();
 
-					return Mono.just(mock(CallToolResult.class));
-				});
+				return Mono.just(mock(CallToolResult.class));
+			})
+			.build();
 
 		var server = McpServer.async(mcpServerTransportProvider).serverInfo("test-server", "1.0.0").tools(tool).build();
 
@@ -151,31 +153,33 @@ void testCreateMessageSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var createMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(createMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var createMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(createMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -226,31 +230,33 @@ void testCreateMessageWithRequestTimeoutSuccess() throws InterruptedException {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -298,31 +304,33 @@ void testCreateMessageWithRequestTimeoutFail() throws InterruptedException {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-
-					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-								new McpSchema.TextContent("Test message"))))
-						.modelPreferences(ModelPreferences.builder()
-							.hints(List.of())
-							.costPriority(1.0)
-							.speedPriority(1.0)
-							.intelligencePriority(1.0)
-							.build())
-						.build();
-
-					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.role()).isEqualTo(Role.USER);
-						assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
-						assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
-						assertThat(result.model()).isEqualTo("MockModelName");
-						assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
-					}).verifyComplete();
-
-					return Mono.just(callResponse);
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
+					.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+							new McpSchema.TextContent("Test message"))))
+					.modelPreferences(ModelPreferences.builder()
+						.hints(List.of())
+						.costPriority(1.0)
+						.speedPriority(1.0)
+						.intelligencePriority(1.0)
+						.build())
+					.build();
+
+				StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.role()).isEqualTo(Role.USER);
+					assertThat(result.content()).isInstanceOf(McpSchema.TextContent.class);
+					assertThat(((McpSchema.TextContent) result.content()).text()).isEqualTo("Test message");
+					assertThat(result.model()).isEqualTo("MockModelName");
+					assertThat(result.stopReason()).isEqualTo(CreateMessageResult.StopReason.STOP_SEQUENCE);
+				}).verifyComplete();
+
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -348,13 +356,15 @@ void testCreateMessageWithRequestTimeoutFail() throws InterruptedException {
 	// @Disabled
 	void testCreateElicitationWithoutElicitationCapabilities() {
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.createElicitation(mock(ElicitRequest.class)).block();
+				exchange.createElicitation(mock(ElicitRequest.class)).block();
 
-					return Mono.just(mock(CallToolResult.class));
-				});
+				return Mono.just(mock(CallToolResult.class));
+			})
+			.build();
 
 		var server = McpServer.async(mcpServerTransportProvider).serverInfo("test-server", "1.0.0").tools(tool).build();
 
@@ -388,23 +398,25 @@ void testCreateElicitationSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -454,23 +466,25 @@ void testCreateElicitationWithRequestTimeoutSuccess() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -517,23 +531,25 @@ void testCreateElicitationWithRequestTimeoutFail() {
 		CallToolResult callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")),
 				null);
 
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					var elicitationRequest = ElicitRequest.builder()
-						.message("Test message")
-						.requestedSchema(
-								Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
-						.build();
+				var elicitationRequest = ElicitRequest.builder()
+					.message("Test message")
+					.requestedSchema(
+							Map.of("type", "object", "properties", Map.of("message", Map.of("type", "string"))))
+					.build();
 
-					StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
-						assertThat(result).isNotNull();
-						assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
-						assertThat(result.content().get("message")).isEqualTo("Test message");
-					}).verifyComplete();
+				StepVerifier.create(exchange.createElicitation(elicitationRequest)).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.action()).isEqualTo(ElicitResult.Action.ACCEPT);
+					assertThat(result.content().get("message")).isEqualTo("Test message");
+				}).verifyComplete();
 
-					return Mono.just(callResponse);
-				});
+				return Mono.just(callResponse);
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")
@@ -602,13 +618,15 @@ void testRootsSuccess() {
 	@Test
 	void testRootsWithoutCapability() {
 
-		McpServerFeatures.SyncToolSpecification tool = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
+		McpServerFeatures.SyncToolSpecification tool = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
 
-					exchange.listRoots(); // try to list roots
+				exchange.listRoots(); // try to list roots
 
-					return mock(CallToolResult.class);
-				});
+				return mock(CallToolResult.class);
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider).rootsChangeHandler((exchange, rootsUpdate) -> {
 		}).tools(tool).build();
@@ -726,17 +744,19 @@ void testRootsServerCloseWithActiveSubscription() {
 	void testToolCallSuccess() {
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		var mcpServer = McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().tools(true).build())
@@ -762,17 +782,19 @@ void testToolCallSuccess() {
 	void testToolListChangeHandlingSuccess() {
 
 		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
-		McpServerFeatures.SyncToolSpecification tool1 = new McpServerFeatures.SyncToolSpecification(
-				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
-					// perform a blocking call to a remote service
-					String response = RestClient.create()
-						.get()
-						.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
-						.retrieve()
-						.body(String.class);
-					assertThat(response).isNotBlank();
-					return callResponse;
-				});
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+				// perform a blocking call to a remote service
+				String response = RestClient.create()
+					.get()
+					.uri("https://raw.githubusercontent.com/modelcontextprotocol/java-sdk/refs/heads/main/README.md")
+					.retrieve()
+					.body(String.class);
+				assertThat(response).isNotBlank();
+				return callResponse;
+			})
+			.build();
 
 		AtomicReference<List<Tool>> rootsRef = new AtomicReference<>();
 
@@ -813,9 +835,10 @@ void testToolListChangeHandlingSuccess() {
 			});
 
 			// Add a new tool
-			McpServerFeatures.SyncToolSpecification tool2 = new McpServerFeatures.SyncToolSpecification(
-					new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema),
-					(exchange, request) -> callResponse);
+			McpServerFeatures.SyncToolSpecification tool2 = McpServerFeatures.SyncToolSpecification.builder()
+				.tool(new McpSchema.Tool("tool2", "tool2 description", emptyJsonSchema))
+				.callTool((exchange, request) -> callResponse)
+				.build();
 
 			mcpServer.addTool(tool2);
 
@@ -849,59 +872,60 @@ void testLoggingNotification() {
 		List<McpSchema.LoggingMessageNotification> receivedNotifications = new ArrayList<>();
 
 		// Create server with a tool that sends logging notifications
-		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
-				new McpSchema.Tool("logging-test", "Test logging notifications", emptyJsonSchema),
-				(exchange, request) -> {
-
-					// Create and send notifications with different levels
-
-					// This should be filtered out (DEBUG < NOTICE)
-					exchange
-						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
-							.level(McpSchema.LoggingLevel.DEBUG)
-							.logger("test-logger")
-							.data("Debug message")
-							.build())
-						.block();
-
-					// This should be sent (NOTICE >= NOTICE)
-					exchange
-						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
-							.level(McpSchema.LoggingLevel.NOTICE)
-							.logger("test-logger")
-							.data("Notice message")
-							.build())
-						.block();
-
-					// This should be sent (ERROR > NOTICE)
-					exchange
-						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
-							.level(McpSchema.LoggingLevel.ERROR)
-							.logger("test-logger")
-							.data("Error message")
-							.build())
-						.block();
-
-					// This should be filtered out (INFO < NOTICE)
-					exchange
-						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
-							.level(McpSchema.LoggingLevel.INFO)
-							.logger("test-logger")
-							.data("Another info message")
-							.build())
-						.block();
-
-					// This should be sent (ERROR >= NOTICE)
-					exchange
-						.loggingNotification(McpSchema.LoggingMessageNotification.builder()
-							.level(McpSchema.LoggingLevel.ERROR)
-							.logger("test-logger")
-							.data("Another error message")
-							.build())
-						.block();
-
-					return Mono.just(new CallToolResult("Logging test completed", false));
-				});
+		McpServerFeatures.AsyncToolSpecification tool = McpServerFeatures.AsyncToolSpecification.builder()
+			.tool(new McpSchema.Tool("logging-test", "Test logging notifications", emptyJsonSchema))
+			.callTool((exchange, request) -> {
+
+				// Create and send notifications with different levels
+
+				// This should be filtered out (DEBUG < NOTICE)
+				exchange
+					.loggingNotification(McpSchema.LoggingMessageNotification.builder()
+						.level(McpSchema.LoggingLevel.DEBUG)
+						.logger("test-logger")
+						.data("Debug message")
+						.build())
+					.block();
+
+				// This should be sent (NOTICE >= NOTICE)
+				exchange
+					.loggingNotification(McpSchema.LoggingMessageNotification.builder()
+						.level(McpSchema.LoggingLevel.NOTICE)
+						.logger("test-logger")
+						.data("Notice message")
+						.build())
+					.block();
+
+				// This should be sent (ERROR > NOTICE)
+				exchange
+					.loggingNotification(McpSchema.LoggingMessageNotification.builder()
+						.level(McpSchema.LoggingLevel.ERROR)
+						.logger("test-logger")
+						.data("Error message")
+						.build())
+					.block();
+
+				// This should be filtered out (INFO < NOTICE)
+				exchange
+					.loggingNotification(McpSchema.LoggingMessageNotification.builder()
+						.level(McpSchema.LoggingLevel.INFO)
+						.logger("test-logger")
+						.data("Another info message")
+						.build())
+					.block();
+
+				// This should be sent (ERROR >= NOTICE)
+				exchange
+					.loggingNotification(McpSchema.LoggingMessageNotification.builder()
+						.level(McpSchema.LoggingLevel.ERROR)
+						.logger("test-logger")
+						.data("Another error message")
+						.build())
+					.block();
+
+				return Mono.just(new CallToolResult("Logging test completed", false));
+			})
+			.build();
 
 		var mcpServer = McpServer.async(mcpServerTransportProvider)
 			.serverInfo("test-server", "1.0.0")