refactor: improve MCP client code organization and robustness

- Add null parameter validation in client builders
- Enhance JavaDoc documentation for tools and resources
- Reorganize McpAsyncClient methods by functionality
- Fix sampling handler test setup

mcp/src/main/java/org/springframework/ai/mcp/client/McpAsyncClient.java

@@ -47,6 +47,7 @@ import org.springframework.ai.mcp.spec.McpSchema.ListPromptsResult;
 import org.springframework.ai.mcp.spec.McpSchema.PaginatedRequest;
 import org.springframework.ai.mcp.spec.McpSchema.Root;
 import org.springframework.ai.mcp.spec.McpTransport;
+import org.springframework.ai.mcp.util.Assert;
 import org.springframework.ai.mcp.util.Utils;
 
 /**
@@ -119,6 +120,10 @@ public class McpAsyncClient {
 			List<Consumer<List<McpSchema.Prompt>>> promptsChangeConsumers,
 			Function<CreateMessageRequest, CreateMessageResult> samplingHandler) {
 
+		Assert.notNull(transport, "Transport must not be null");
+		Assert.notNull(requestTimeout, "Request timeout must not be null");
+		Assert.notNull(clientInfo, "Client info must not be null");
+
 		this.clientInfo = clientInfo;
 
 		this.clientCapabilities = (clientCapabilities != null) ? clientCapabilities
@@ -177,133 +182,9 @@ public class McpAsyncClient {
 
 	}
 
-	public Mono<Void> addRoot(Root root) {
-
-		if (root == null) {
-			return Mono.error(new McpError("Root must not be null"));
-		}
-
-		if (this.clientCapabilities.roots() == null) {
-			return Mono.error(new McpError("Client must be configured with roots capabilities"));
-		}
-
-		if (this.roots.containsKey(root.uri())) {
-			return Mono.error(new McpError("Root with uri '" + root.uri() + "' already exists"));
-		}
-
-		this.roots.put(root.uri(), root);
-
-		logger.info("Added root: {}", root);
-
-		if (this.clientCapabilities.roots().listChanged()) {
-			return this.rootsListChangedNotification();
-		}
-		return Mono.empty();
-	}
-
-	public Mono<Void> removeRoot(String rootUri) {
-
-		if (rootUri == null) {
-			return Mono.error(new McpError("Root uri must not be null"));
-		}
-
-		if (this.clientCapabilities.roots() == null) {
-			return Mono.error(new McpError("Client must be configured with roots capabilities"));
-		}
-
-		Root removed = this.roots.remove(rootUri);
-
-		if (removed != null) {
-			logger.info("Removed Root: {}", rootUri);
-			if (this.clientCapabilities.roots().listChanged()) {
-				return this.rootsListChangedNotification();
-			}
-			return Mono.empty();
-		}
-		return Mono.error(new McpError("Root with uri '" + rootUri + "' not found"));
-	}
-
-	private RequestHandler samplingCreateMessageHandler() {
-		return params -> {
-			McpSchema.CreateMessageRequest request = transport.unmarshalFrom(params,
-					new TypeReference<McpSchema.CreateMessageRequest>() {
-					});
-
-			CreateMessageResult response = this.samplingHandler.apply(request);
-
-			return Mono.just(response);
-		};
-	}
-
-	private RequestHandler rootsListRequestHandler() {
-		return params -> {
-			McpSchema.PaginatedRequest request = transport.unmarshalFrom(params,
-					new TypeReference<McpSchema.PaginatedRequest>() {
-					});
-
-			List<Root> roots = this.roots.values().stream().toList();
-
-			return Mono.just(roots);
-		};
-	}
-
-	private NotificationHandler toolsChangeNotificationHandler(
-			List<Consumer<List<McpSchema.Tool>>> toolsChangeConsumers) {
-
-		return new NotificationHandler() {
-			@Override
-			public Mono<Void> handle(Object params) {
-				// TODO: add support for cursor/pagination
-				return listTools().flatMap(listToolsResult -> Mono.fromRunnable(() -> {
-					for (Consumer<List<McpSchema.Tool>> toolsChangeConsumer : toolsChangeConsumers) {
-						toolsChangeConsumer.accept(listToolsResult.tools());
-					}
-				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
-					logger.error("Error handling tools list change notification", error);
-					return Mono.empty();
-				}).then(); // Convert to Mono<Void>
-			}
-		};
-	};
-
-	private NotificationHandler resourcesChangeNotificationHandler(
-			List<Consumer<List<McpSchema.Resource>>> resourcesChangeConsumers) {
-
-		return new NotificationHandler() {
-			@Override
-			public Mono<Void> handle(Object params) {
-				// TODO: add support for cursor/pagination
-				return listResources().flatMap(listResourcesResult -> Mono.fromRunnable(() -> {
-					for (Consumer<List<McpSchema.Resource>> resourceChangeConsumer : resourcesChangeConsumers) {
-						resourceChangeConsumer.accept(listResourcesResult.resources());
-					}
-				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
-					logger.error("Error handling resources list change notification", error);
-					return Mono.empty();
-				}).then(); // Convert to Mono<Void>
-			}
-		};
-	};
-
-	private NotificationHandler promptsChangeNotificationHandler(
-			List<Consumer<List<McpSchema.Prompt>>> promptsChangeConsumers) {
-
-		return new NotificationHandler() {
-			@Override
-			public Mono<Void> handle(Object params) {
-				// TODO: add support for cursor/pagination
-				return listPrompts().flatMap(listPromptsResult -> Mono.fromRunnable(() -> {
-					for (Consumer<List<McpSchema.Prompt>> promptChangeConsumer : promptsChangeConsumers) {
-						promptChangeConsumer.accept(listPromptsResult.prompts());
-					}
-				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
-					logger.error("Error handling prompts list change notification", error);
-					return Mono.empty();
-				}).then(); // Convert to Mono<Void>
-			}
-		};
-	};
-
+	// --------------------------
+	// Lifecycle
+	// --------------------------
 	/**
 	 * The initialization phase MUST be the first interaction between client and server.
 	 * During this phase, the client and server:
@@ -358,13 +239,18 @@ public class McpAsyncClient {
 		});
 	}
 
-	/**
-	 * Send a roots/list_changed notification.
-	 */
-	public Mono<Void> rootsListChangedNotification() {
-		return this.mcpSession.sendNotification("notifications/roots/list_changed");
+	public void close() {
+		this.mcpSession.close();
 	}
 
+	public Mono<Void> closeGracefully() {
+		return this.mcpSession.closeGracefully();
+	}
+
+	// --------------------------
+	// Basic Utilites
+	// --------------------------
+
 	/**
 	 * Send a synchronous ping request.
 	 */
@@ -373,6 +259,90 @@ public class McpAsyncClient {
 		});
 	}
 
+	// --------------------------
+	// Roots
+	// --------------------------
+	public Mono<Void> addRoot(Root root) {
+
+		if (root == null) {
+			return Mono.error(new McpError("Root must not be null"));
+		}
+
+		if (this.clientCapabilities.roots() == null) {
+			return Mono.error(new McpError("Client must be configured with roots capabilities"));
+		}
+
+		if (this.roots.containsKey(root.uri())) {
+			return Mono.error(new McpError("Root with uri '" + root.uri() + "' already exists"));
+		}
+
+		this.roots.put(root.uri(), root);
+
+		logger.info("Added root: {}", root);
+
+		if (this.clientCapabilities.roots().listChanged()) {
+			return this.rootsListChangedNotification();
+		}
+		return Mono.empty();
+	}
+
+	public Mono<Void> removeRoot(String rootUri) {
+
+		if (rootUri == null) {
+			return Mono.error(new McpError("Root uri must not be null"));
+		}
+
+		if (this.clientCapabilities.roots() == null) {
+			return Mono.error(new McpError("Client must be configured with roots capabilities"));
+		}
+
+		Root removed = this.roots.remove(rootUri);
+
+		if (removed != null) {
+			logger.info("Removed Root: {}", rootUri);
+			if (this.clientCapabilities.roots().listChanged()) {
+				return this.rootsListChangedNotification();
+			}
+			return Mono.empty();
+		}
+		return Mono.error(new McpError("Root with uri '" + rootUri + "' not found"));
+	}
+
+	/**
+	 * Manually, send a roots/list_changed notification. The addRoot and removeRoot
+	 * methods automatically send the roots/list_changed notification.
+	 */
+	public Mono<Void> rootsListChangedNotification() {
+		return this.mcpSession.sendNotification("notifications/roots/list_changed");
+	}
+
+	private RequestHandler rootsListRequestHandler() {
+		return params -> {
+			McpSchema.PaginatedRequest request = transport.unmarshalFrom(params,
+					new TypeReference<McpSchema.PaginatedRequest>() {
+					});
+
+			List<Root> roots = this.roots.values().stream().toList();
+
+			return Mono.just(roots);
+		};
+	}
+
+	// --------------------------
+	// Sampling
+	// --------------------------
+	private RequestHandler samplingCreateMessageHandler() {
+		return params -> {
+			McpSchema.CreateMessageRequest request = transport.unmarshalFrom(params,
+					new TypeReference<McpSchema.CreateMessageRequest>() {
+					});
+
+			CreateMessageResult response = this.samplingHandler.apply(request);
+
+			return Mono.just(response);
+		};
+	}
+
 	// --------------------------
 	// Tools
 	// --------------------------
@@ -383,32 +353,74 @@ public class McpAsyncClient {
 	};
 
 	/**
-	 * Send a tools/call request.
-	 * @param callToolRequest the call tool request.
-	 * @return the call tool result.
+	 * Calls a tool provided by the server. Tools enable servers to expose executable
+	 * functionality that can interact with external systems, perform computations, and
+	 * take actions in the real world.
+	 * @param callToolRequest The request containing: - name: The name of the tool to call
+	 * (must match a tool name from tools/list) - arguments: Arguments that conform to the
+	 * tool's input schema
+	 * @return A Mono that emits the tool execution result containing: - content: List of
+	 * content items (text, images, or embedded resources) representing the tool's output
+	 * - isError: Boolean indicating if the execution failed (true) or succeeded
+	 * (false/absent)
 	 */
 	public Mono<McpSchema.CallToolResult> callTool(McpSchema.CallToolRequest callToolRequest) {
 		return this.mcpSession.sendRequest("tools/call", callToolRequest, CALL_TOOL_RESULT_TYPE_REF);
 	}
 
 	/**
-	 * Send a tools/list request.
-	 * @return the list of tools result.
+	 * Retrieves the list of all tools provided by the server.
+	 * @return A Mono that emits the list of tools result containing: - tools: List of
+	 * available tools, each with a name, description, and input schema - nextCursor:
+	 * Optional cursor for pagination if more tools are available
 	 */
 	public Mono<McpSchema.ListToolsResult> listTools() {
 		return this.listTools(null);
 	}
 
 	/**
-	 * Send a tools/list request.
-	 * @param cursor the cursor
-	 * @return the list of tools result.
+	 * Retrieves a paginated list of tools provided by the server.
+	 * @param cursor Optional pagination cursor from a previous list request
+	 * @return A Mono that emits the list of tools result containing: - tools: List of
+	 * available tools, each with a name, description, and input schema - nextCursor:
+	 * Optional cursor for pagination if more tools are available
 	 */
 	public Mono<McpSchema.ListToolsResult> listTools(String cursor) {
 		return this.mcpSession.sendRequest("tools/list", new McpSchema.PaginatedRequest(cursor),
 				LIST_TOOLS_RESULT_TYPE_REF);
 	}
 
+	/**
+	 * Creates a notification handler for tools/list_changed notifications from the
+	 * server. When the server's available tools change, it sends a notification to inform
+	 * connected clients. This handler automatically fetches the updated tool list and
+	 * distributes it to all registered consumers.
+	 * @param toolsChangeConsumers List of consumers that will be notified when the tools
+	 * list changes. Each consumer receives the complete updated list of tools.
+	 * @return A NotificationHandler that processes tools/list_changed notifications by:
+	 * 1. Fetching the current list of tools from the server 2. Distributing the updated
+	 * list to all registered consumers 3. Handling any errors that occur during this
+	 * process
+	 */
+	private NotificationHandler toolsChangeNotificationHandler(
+			List<Consumer<List<McpSchema.Tool>>> toolsChangeConsumers) {
+
+		return new NotificationHandler() {
+			@Override
+			public Mono<Void> handle(Object params) {
+				// TODO: add support for cursor/pagination
+				return listTools().flatMap(listToolsResult -> Mono.fromRunnable(() -> {
+					for (Consumer<List<McpSchema.Tool>> toolsChangeConsumer : toolsChangeConsumers) {
+						toolsChangeConsumer.accept(listToolsResult.tools());
+					}
+				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
+					logger.error("Error handling tools list change notification", error);
+					return Mono.empty();
+				}).then(); // Convert to Mono<Void>
+			}
+		};
+	};
+
 	// --------------------------
 	// Resources
 	// --------------------------
@@ -512,6 +524,25 @@ public class McpAsyncClient {
 		return this.mcpSession.sendRequest("resources/unsubscribe", unsubscribeRequest, VOID_TYPE_REFERENCE);
 	}
 
+	private NotificationHandler resourcesChangeNotificationHandler(
+			List<Consumer<List<McpSchema.Resource>>> resourcesChangeConsumers) {
+
+		return new NotificationHandler() {
+			@Override
+			public Mono<Void> handle(Object params) {
+				// TODO: add support for cursor/pagination
+				return listResources().flatMap(listResourcesResult -> Mono.fromRunnable(() -> {
+					for (Consumer<List<McpSchema.Resource>> resourceChangeConsumer : resourcesChangeConsumers) {
+						resourceChangeConsumer.accept(listResourcesResult.resources());
+					}
+				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
+					logger.error("Error handling resources list change notification", error);
+					return Mono.empty();
+				}).then(); // Convert to Mono<Void>
+			}
+		};
+	};
+
 	// --------------------------
 	// Prompts
 	// --------------------------
@@ -556,12 +587,23 @@ public class McpAsyncClient {
 		return this.mcpSession.sendNotification("notifications/prompts/list_changed");
 	}
 
-	public void close() {
-		this.mcpSession.close();
-	}
+	private NotificationHandler promptsChangeNotificationHandler(
+			List<Consumer<List<McpSchema.Prompt>>> promptsChangeConsumers) {
 
-	public Mono<Void> closeGracefully() {
-		return this.mcpSession.closeGracefully();
-	}
+		return new NotificationHandler() {
+			@Override
+			public Mono<Void> handle(Object params) {
+				// TODO: add support for cursor/pagination
+				return listPrompts().flatMap(listPromptsResult -> Mono.fromRunnable(() -> {
+					for (Consumer<List<McpSchema.Prompt>> promptChangeConsumer : promptsChangeConsumers) {
+						promptChangeConsumer.accept(listPromptsResult.prompts());
+					}
+				}).subscribeOn(Schedulers.boundedElastic())).onErrorResume(error -> {
+					logger.error("Error handling prompts list change notification", error);
+					return Mono.empty();
+				}).then(); // Convert to Mono<Void>
+			}
+		};
+	};
 
 }

mcp/src/main/java/org/springframework/ai/mcp/client/McpClient.java

@@ -108,16 +108,19 @@ public interface McpClient {
 		}
 
 		public Builder capabilities(ClientCapabilities capabilities) {
+			Assert.notNull(capabilities, "Capabilities must not be null");
 			this.capabilities = capabilities;
 			return this;
 		}
 
 		public Builder clientInfo(Implementation clientInfo) {
+			Assert.notNull(clientInfo, "Client info must not be null");
 			this.clientInfo = clientInfo;
 			return this;
 		}
 
 		public Builder roots(List<Root> roots) {
+			Assert.notNull(roots, "Roots must not be null");
 			for (Root root : roots) {
 				this.roots.put(root.uri(), root);
 			}
@@ -125,6 +128,7 @@ public interface McpClient {
 		}
 
 		public Builder roots(Root... roots) {
+			Assert.notNull(roots, "Roots must not be null");
 			for (Root root : roots) {
 				this.roots.put(root.uri(), root);
 			}
@@ -132,21 +136,25 @@ public interface McpClient {
 		}
 
 		public Builder sampling(Function<CreateMessageRequest, CreateMessageResult> samplingHandler) {
+			Assert.notNull(samplingHandler, "Sampling handler must not be null");
 			this.samplingHandler = samplingHandler;
 			return this;
 		}
 
 		public Builder toolsChangeConsumer(Consumer<List<McpSchema.Tool>> toolsChangeConsumer) {
+			Assert.notNull(toolsChangeConsumer, "Tools change consumer must not be null");
 			this.toolsChangeConsumers.add(toolsChangeConsumer);
 			return this;
 		}
 
 		public Builder resourcesChangeConsumer(Consumer<List<McpSchema.Resource>> resourcesChangeConsumer) {
+			Assert.notNull(resourcesChangeConsumer, "Resources change consumer must not be null");
 			this.resourcesChangeConsumers.add(resourcesChangeConsumer);
 			return this;
 		}
 
 		public Builder promptsChangeConsumer(Consumer<List<McpSchema.Prompt>> promptsChangeConsumer) {
+			Assert.notNull(promptsChangeConsumer, "Prompts change consumer must not be null");
 			this.promptsChangeConsumers.add(promptsChangeConsumer);
 			return this;
 		}

mcp/src/main/java/org/springframework/ai/mcp/client/McpSyncClient.java

@@ -130,26 +130,36 @@ public class McpSyncClient implements AutoCloseable {
 	// Tools
 	// --------------------------
 	/**
-	 * Send a tools/call request.
-	 * @param callToolRequest the call tool request.
-	 * @return the call tool result.
+	 * Calls a tool provided by the server. Tools enable servers to expose executable
+	 * functionality that can interact with external systems, perform computations, and
+	 * take actions in the real world.
+	 * @param callToolRequest The request containing: - name: The name of the tool to call
+	 * (must match a tool name from tools/list) - arguments: Arguments that conform to the
+	 * tool's input schema
+	 * @return The tool execution result containing: - content: List of content items
+	 * (text, images, or embedded resources) representing the tool's output - isError:
+	 * Boolean indicating if the execution failed (true) or succeeded (false/absent)
 	 */
 	public McpSchema.CallToolResult callTool(McpSchema.CallToolRequest callToolRequest) {
 		return this.delegate.callTool(callToolRequest).block();
 	}
 
 	/**
-	 * Send a tools/list request.
-	 * @return the list of tools result.
+	 * Retrieves the list of all tools provided by the server.
+	 * @return The list of tools result containing: - tools: List of available tools, each
+	 * with a name, description, and input schema - nextCursor: Optional cursor for
+	 * pagination if more tools are available
 	 */
 	public McpSchema.ListToolsResult listTools() {
 		return this.delegate.listTools().block();
 	}
 
 	/**
-	 * Send a tools/list request.
-	 * @param cursor the cursor
-	 * @return the list of tools result.
+	 * Retrieves a paginated list of tools provided by the server.
+	 * @param cursor Optional pagination cursor from a previous list request
+	 * @return The list of tools result containing: - tools: List of available tools, each
+	 * with a name, description, and input schema - nextCursor: Optional cursor for
+	 * pagination if more tools are available
 	 */
 	public McpSchema.ListToolsResult listTools(String cursor) {
 		return this.delegate.listTools(cursor).block();

mcp/src/main/java/org/springframework/ai/mcp/spec/McpSchema.java

@@ -364,6 +364,8 @@ public class McpSchema {
 	 * by clients to improve the LLM's understanding of available resources. It can be
 	 * thought of like a "hint" to the model.
 	 * @param mimeType The MIME type of this resource, if known.
+	 * @param annotations Optional annotations for the client. The client can use
+	 * annotations to inform how objects are used or displayed.
 	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	@JsonIgnoreProperties(ignoreUnknown = true)
@@ -387,6 +389,8 @@ public class McpSchema {
 	 * by clients to improve the LLM's understanding of available resources. It can be
 	 * thought of like a "hint" to the model.
 	 * @param mimeType The MIME type of this resource, if known.
+	 * @param annotations Optional annotations for the client. The client can use
+	 * annotations to inform how objects are used or displayed.
 	 * @see <a href="https://datatracker.ietf.org/doc/html/rfc6570">RFC 6570</a>
 	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
@@ -574,12 +578,32 @@ public class McpSchema {
 	// ---------------------------
 	// Tool Interfaces
 	// ---------------------------
+	/**
+	 * The server's response to a tools/list request from the client.
+	 *
+	 * @param tools A list of tools that the server provides.
+	 * @param nextCursor An optional cursor for pagination. If present, indicates there
+	 * are more tools available.
+	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	public record ListToolsResult( // @formatter:off
 		@JsonProperty("tools") List<Tool> tools,
 		@JsonProperty("nextCursor") String nextCursor) {
 	}// @formatter:on
 
+	/**
+	 * Represents a tool that the server provides. Tools enable servers to expose
+	 * executable functionality to the system. Through these tools, you can interact with
+	 * external systems, perform computations, and take actions in the real world.
+	 *
+	 * @param name A unique identifier for the tool. This name is used when calling the
+	 * tool.
+	 * @param description A human-readable description of what the tool does. This can be
+	 * used by clients to improve the LLM's understanding of available tools.
+	 * @param inputSchema A JSON Schema object that describes the expected structure of
+	 * the arguments when calling this tool. This allows clients to validate tool
+	 * arguments before sending them to the server.
+	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	public record Tool( // @formatter:off
 		@JsonProperty("name") String name,
@@ -601,12 +625,28 @@ public class McpSchema {
 		}
 	}
 
+	/**
+	 * Used by the client to call a tool provided by the server.
+	 *
+	 * @param name The name of the tool to call. This must match a tool name from
+	 * tools/list.
+	 * @param arguments Arguments to pass to the tool. These must conform to the tool's
+	 * input schema.
+	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	public record CallToolRequest(// @formatter:off
 		@JsonProperty("name") String name,
 		@JsonProperty("arguments") Map<String, Object> arguments) implements Request {
 	}// @formatter:off
 
+	/**
+	 * The server's response to a tools/call request from the client.
+	 *
+	 * @param content A list of content items representing the tool's output. Each item can be text, an image,
+	 *                or an embedded resource.
+	 * @param isError If true, indicates that the tool execution failed and the content contains error information.
+	 *                If false or absent, indicates successful execution.
+	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	public record CallToolResult( // @formatter:off
 		@JsonProperty("content") List<Content> content,
@@ -643,16 +683,16 @@ public class McpSchema {
 
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	public record CreateMessageResult(// @formatter:off
-		@JsonProperty("role") Role role, 
-		@JsonProperty("content") Content content, 
-		@JsonProperty("model") String model, 
+		@JsonProperty("role") Role role,
+		@JsonProperty("content") Content content,
+		@JsonProperty("model") String model,
 		@JsonProperty("stopReason") StopReason stopReason) {
 		
 		public enum StopReason {
 			@JsonProperty("end_turn") END_TURN,
 			@JsonProperty("stop_sequence") STOP_SEQUENCE,
 			@JsonProperty("max_tokens") MAX_TOKENS
-		} 
+		}
 	}// @formatter:on
 
 	// ---------------------------

mcp/src/main/java/org/springframework/ai/mcp/spec/McpTransport.java

@@ -93,6 +93,13 @@ public interface McpTransport {
 	 */
 	Mono<Void> sendMessage(JSONRPCMessage message);
 
+	/**
+	 * Unmarshals the given data into an object of the specified type.
+	 * @param <T> the type of the object to unmarshal
+	 * @param data the data to unmarshal
+	 * @param typeRef the type reference for the object to unmarshal
+	 * @return the unmarshalled object
+	 */
 	<T> T unmarshalFrom(Object data, TypeReference<T> typeRef);
 
 }

mcp/src/test/java/org/springframework/ai/mcp/client/AbstractMcpAsyncClientTests.java

@@ -22,6 +22,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import reactor.test.StepVerifier;
 
@@ -225,7 +226,8 @@ public abstract class AbstractMcpAsyncClientTests {
 			.hasMessageContaining("Root with uri 'nonexistent-uri' not found");
 	}
 
-	// @Test
+	@Test
+	@Disabled
 	void testReadResource() {
 		StepVerifier.create(mcpAsyncClient.listResources()).consumeNextWith(resources -> {
 			if (!resources.resources().isEmpty()) {

mcp/src/test/java/org/springframework/ai/mcp/client/McpAsyncClientResponseHandlerTests.java

@@ -365,7 +365,6 @@ class McpAsyncClientResponseHandlerTests {
 		// Create client with sampling capability but null handler
 		McpAsyncClient asyncMcpClient = McpClient.using(transport)
 			.capabilities(ClientCapabilities.builder().sampling().build())
-			.sampling(null) // Null handler
 			.async();
 
 		// Create a mock create message request