Fix everything-server-based integration tests (#756)

* Pin `npx @modelcontextprotocol/server-everything` version to `2025.12.18`.
* Replace `tzolov/mcp-everything-server` Docker image with `node:lts-alpine` + `npx` command.
* Handle HTTP 202 special case.
* Fix test assertions.

The recent rollout of everything-server broke integration tests which take the latest version from the node registry.
This PR unifies the everything-server usage - the Testcontainers Docker setup uses the same version as the STDIO npx-based tests and no longer relies on tzolov/mcp-everything-server.

Signed-off-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>

mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransport.java

@@ -491,7 +491,9 @@ public class HttpClientStreamableHttpTransport implements McpClientTransport {
 						.firstValue(HttpHeaders.CONTENT_LENGTH)
 						.orElse(null);
 
-					if (contentType.isBlank() || "0".equals(contentLength)) {
+					// For empty content or HTTP code 202 (ACCEPTED), assume success
+					if (contentType.isBlank() || "0".equals(contentLength) || statusCode == 202) {
+						// if (contentType.isBlank() || "0".equals(contentLength)) {
 						logger.debug("No body returned for POST in session {}", sessionRepresentation);
 						// No content type means no response body, so we can just
 						// return an empty stream

mcp-core/src/test/java/io/modelcontextprotocol/client/AbstractMcpAsyncClientResiliencyTests.java

@@ -48,10 +48,9 @@ public abstract class AbstractMcpAsyncClientResiliencyTests {
 	static Network network = Network.newNetwork();
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withNetwork(network)
 		.withNetworkAliases("everything-server")

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

@@ -72,7 +72,7 @@ public abstract class AbstractMcpAsyncClientTests {
 	}
 
 	protected Duration getInitializationTimeout() {
-		return Duration.ofSeconds(2);
+		return Duration.ofSeconds(20);
 	}
 
 	McpAsyncClient client(McpClientTransport transport) {
@@ -503,57 +503,64 @@ public abstract class AbstractMcpAsyncClientTests {
 
 	@Test
 	void testReadResource() {
+		AtomicInteger resourceCount = new AtomicInteger();
 		withClient(createMcpTransport(), client -> {
 			Flux<McpSchema.ReadResourceResult> resources = client.initialize()
 				.then(client.listResources(null))
-				.flatMapMany(r -> Flux.fromIterable(r.resources()))
+				.flatMapMany(r -> {
+					List<Resource> l = r.resources();
+					resourceCount.set(l.size());
+					return Flux.fromIterable(l);
+				})
 				.flatMap(r -> client.readResource(r));
 
-			StepVerifier.create(resources).recordWith(ArrayList::new).consumeRecordedWith(readResourceResults -> {
+			StepVerifier.create(resources)
+				.recordWith(ArrayList::new)
+				.thenConsumeWhile(res -> true)
+				.consumeRecordedWith(readResourceResults -> {
+					assertThat(readResourceResults.size()).isEqualTo(resourceCount.get());
+					for (ReadResourceResult result : readResourceResults) {
 
-				for (ReadResourceResult result : readResourceResults) {
+						assertThat(result).isNotNull();
+						assertThat(result.contents()).isNotNull().isNotEmpty();
 
-					assertThat(result).isNotNull();
+						// Validate each content item
-					assertThat(result.contents()).isNotNull().isNotEmpty();
+						for (ResourceContents content : result.contents()) {
+							assertThat(content).isNotNull();
+							assertThat(content.uri()).isNotNull().isNotEmpty();
+							assertThat(content.mimeType()).isNotNull().isNotEmpty();
 
-					// Validate each content item
+							// Validate content based on its type with more comprehensive
-					for (ResourceContents content : result.contents()) {
+							// checks
-						assertThat(content).isNotNull();
+							switch (content.mimeType()) {
-						assertThat(content.uri()).isNotNull().isNotEmpty();
+								case "text/plain" -> {
-						assertThat(content.mimeType()).isNotNull().isNotEmpty();
+									TextResourceContents textContent = assertInstanceOf(TextResourceContents.class,
-
+											content);
-						// Validate content based on its type with more comprehensive
+									assertThat(textContent.text()).isNotNull().isNotEmpty();
-						// checks
+									assertThat(textContent.uri()).isNotEmpty();
-						switch (content.mimeType()) {
-							case "text/plain" -> {
-								TextResourceContents textContent = assertInstanceOf(TextResourceContents.class,
-										content);
-								assertThat(textContent.text()).isNotNull().isNotEmpty();
-								assertThat(textContent.uri()).isNotEmpty();
-							}
-							case "application/octet-stream" -> {
-								BlobResourceContents blobContent = assertInstanceOf(BlobResourceContents.class,
-										content);
-								assertThat(blobContent.blob()).isNotNull().isNotEmpty();
-								assertThat(blobContent.uri()).isNotNull().isNotEmpty();
-								// Validate base64 encoding format
-								assertThat(blobContent.blob()).matches("^[A-Za-z0-9+/]*={0,2}$");
-							}
-							default -> {
-
-								// Still validate basic properties
-								if (content instanceof TextResourceContents textContent) {
-									assertThat(textContent.text()).isNotNull();
 								}
-								else if (content instanceof BlobResourceContents blobContent) {
+								case "application/octet-stream" -> {
-									assertThat(blobContent.blob()).isNotNull();
+									BlobResourceContents blobContent = assertInstanceOf(BlobResourceContents.class,
+											content);
+									assertThat(blobContent.blob()).isNotNull().isNotEmpty();
+									assertThat(blobContent.uri()).isNotNull().isNotEmpty();
+									// Validate base64 encoding format
+									assertThat(blobContent.blob()).matches("^[A-Za-z0-9+/]*={0,2}$");
+								}
+								default -> {
+
+									// Still validate basic properties
+									if (content instanceof TextResourceContents textContent) {
+										assertThat(textContent.text()).isNotNull();
+									}
+									else if (content instanceof BlobResourceContents blobContent) {
+										assertThat(blobContent.blob()).isNotNull();
+									}
 								}
 							}
 						}
 					}
-				}
+				})
-			})
-				.expectNextCount(10) // Expect 10 elements
 				.verifyComplete();
 		});
 	}
@@ -693,7 +700,6 @@ public abstract class AbstractMcpAsyncClientTests {
 					assertThat(result.capabilities()).isNotNull();
 				}).verifyComplete());
 	}
-
 	// ---------------------------------------
 	// Logging Tests
 	// ---------------------------------------
@@ -773,7 +779,7 @@ public abstract class AbstractMcpAsyncClientTests {
 							if (!(content instanceof McpSchema.TextContent text))
 								return;
 
-							assertThat(text.text()).endsWith(response); // Prefixed
+							assertThat(text.text()).contains(response);
 						});
 
 						// Verify sampling request parameters received in our callback

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

@@ -625,7 +625,7 @@ public abstract class AbstractMcpSyncClientTests {
 					if (!(content instanceof McpSchema.TextContent text))
 						return;
 
-					assertThat(text.text()).endsWith(response); // Prefixed
+					assertThat(text.text()).contains(response);
 				});
 
 				// Verify sampling request parameters received in our callback

mcp-core/src/test/java/io/modelcontextprotocol/client/HttpClientStreamableHttpAsyncClientTests.java

@@ -17,10 +17,9 @@ public class HttpClientStreamableHttpAsyncClientTests extends AbstractMcpAsyncCl
 
 	private static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-core/src/test/java/io/modelcontextprotocol/client/HttpClientStreamableHttpSyncClientTests.java

@@ -30,10 +30,9 @@ public class HttpClientStreamableHttpSyncClientTests extends AbstractMcpSyncClie
 
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-core/src/test/java/io/modelcontextprotocol/client/HttpSseMcpAsyncClientLostConnectionTests.java

@@ -36,10 +36,9 @@ public class HttpSseMcpAsyncClientLostConnectionTests {
 	static Network network = Network.newNetwork();
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withNetwork(network)
 		.withNetworkAliases("everything-server")

mcp-core/src/test/java/io/modelcontextprotocol/client/HttpSseMcpAsyncClientTests.java

@@ -23,10 +23,9 @@ class HttpSseMcpAsyncClientTests extends AbstractMcpAsyncClientTests {
 
 	private static String host = "http://localhost:3004";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-core/src/test/java/io/modelcontextprotocol/client/HttpSseMcpSyncClientTests.java

@@ -36,10 +36,9 @@ class HttpSseMcpSyncClientTests extends AbstractMcpSyncClientTests {
 
 	static String host = "http://localhost:3003";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-core/src/test/java/io/modelcontextprotocol/client/ServerParameterUtils.java

@@ -10,10 +10,12 @@ public final class ServerParameterUtils {
 	public static ServerParameters createServerParameters() {
 		if (System.getProperty("os.name").toLowerCase().contains("win")) {
 			return ServerParameters.builder("cmd.exe")
-				.args("/c", "npx.cmd", "-y", "@modelcontextprotocol/server-everything", "stdio")
+				.args("/c", "npx.cmd", "-y", "@modelcontextprotocol/server-everything@2025.12.18", "stdio")
 				.build();
 		}
-		return ServerParameters.builder("npx").args("-y", "@modelcontextprotocol/server-everything", "stdio").build();
+		return ServerParameters.builder("npx")
+			.args("-y", "@modelcontextprotocol/server-everything@2025.12.18", "stdio")
+			.build();
 	}
 
 }

mcp-core/src/test/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransportTests.java

@@ -58,8 +58,8 @@ class HttpClientSseClientTransportTests {
 	static String host = "http://localhost:3001";
 
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-core/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportTest.java

@@ -40,8 +40,8 @@ class HttpClientStreamableHttpTransportTest {
 		.create(Map.of("test-transport-context-key", "some-value"));
 
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransport.java

@@ -318,7 +318,8 @@ public class WebClientStreamableHttpTransport implements McpClientTransport {
 						long contentLength = response.headers().contentLength().orElse(-1);
 						// Existing SDKs consume notifications with no response body nor
 						// content type
-						if (contentType.isEmpty() || contentLength == 0) {
+						if (contentType.isEmpty() || contentLength == 0
+								|| response.statusCode().equals(HttpStatus.ACCEPTED)) {
 							logger.trace("Message was successfully sent via POST for session {}",
 									sessionRepresentation);
 							// signal the caller that the message was successfully

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/WebClientStreamableHttpAsyncClientTests.java

@@ -19,10 +19,9 @@ public class WebClientStreamableHttpAsyncClientTests extends AbstractMcpAsyncCli
 
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/WebClientStreamableHttpSyncClientTests.java

@@ -19,10 +19,9 @@ public class WebClientStreamableHttpSyncClientTests extends AbstractMcpSyncClien
 
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/WebFluxSseMcpAsyncClientTests.java

@@ -26,13 +26,12 @@ class WebFluxSseMcpAsyncClientTests extends AbstractMcpAsyncClientTests {
 
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
-		.waitingFor(Wait.forHttp("/").forStatusCode(404));
+		.waitingFor(Wait.forHttp("/").forStatusCode(404).forPort(3001));
 
 	@Override
 	protected McpClientTransport createMcpTransport() {

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/WebFluxSseMcpSyncClientTests.java

@@ -25,10 +25,9 @@ class WebFluxSseMcpSyncClientTests extends AbstractMcpSyncClientTests {
 
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransportTest.java

@@ -20,8 +20,8 @@ class WebClientStreamableHttpTransportTest {
 	static WebClient.Builder builder;
 
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/transport/WebFluxSseClientTransportTests.java

@@ -47,8 +47,8 @@ class WebFluxSseClientTransportTests {
 	static String host = "http://localhost:3001";
 
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js sse")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 sse")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withExposedPorts(3001)
 		.waitingFor(Wait.forHttp("/").forStatusCode(404));

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

@@ -47,10 +47,9 @@ public abstract class AbstractMcpAsyncClientResiliencyTests {
 	static Network network = Network.newNetwork();
 	static String host = "http://localhost:3001";
 
-	// Uses the https://github.com/tzolov/mcp-everything-server-docker-image
 	@SuppressWarnings("resource")
-	static GenericContainer<?> container = new GenericContainer<>("docker.io/tzolov/mcp-everything-server:v3")
+	static GenericContainer<?> container = new GenericContainer<>("docker.io/node:lts-alpine3.23")
-		.withCommand("node dist/index.js streamableHttp")
+		.withCommand("npx -y @modelcontextprotocol/server-everything@2025.12.18 streamableHttp")
 		.withLogConsumer(outputFrame -> System.out.println(outputFrame.getUtf8String()))
 		.withNetwork(network)
 		.withNetworkAliases("everything-server")