diff --git a/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxStreamableIntegrationTests.java b/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxStreamableIntegrationTests.java
index 9eba0e57c..9f7021938 100644
--- a/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxStreamableIntegrationTests.java
+++ b/mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxStreamableIntegrationTests.java
@@ -4,29 +4,39 @@
 
 package io.modelcontextprotocol;
 
-import java.time.Duration;
-
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Timeout;
-import org.springframework.http.server.reactive.HttpHandler;
-import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
-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.HttpClientStreamableHttpTransport;
 import io.modelcontextprotocol.client.transport.WebClientStreamableHttpTransport;
 import io.modelcontextprotocol.server.McpServer;
 import io.modelcontextprotocol.server.McpServer.AsyncSpecification;
 import io.modelcontextprotocol.server.McpServer.SyncSpecification;
+import io.modelcontextprotocol.server.McpServerFeatures;
 import io.modelcontextprotocol.server.TestUtil;
 import io.modelcontextprotocol.server.transport.WebFluxStreamableServerTransportProvider;
+import io.modelcontextprotocol.spec.McpError;
+import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
+import io.modelcontextprotocol.spec.McpSchema.Tool;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Timeout;
+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.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.server.RouterFunctions;
 import reactor.netty.DisposableServer;
 import reactor.netty.http.server.HttpServer;
 
+import java.time.Duration;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 @Timeout(15)
 class WebFluxStreamableIntegrationTests extends AbstractMcpClientServerIntegrationTests {
 
@@ -88,4 +98,53 @@ public void after() {
 		}
 	}
 
+	@ParameterizedTest(name = "{0} : {displayName} ")
+	@ValueSource(strings = { "httpclient", "webflux" })
+	void testToolCallThrowMcpError(String clientType) {
+		String emptyJsonSchema = """
+				{
+					"$schema": "http://json-schema.org/draft-07/schema#",
+					"type": "object",
+					"properties": {}
+				}
+				""";
+
+		var clientBuilder = clientBuilders.get(clientType);
+
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(Tool.builder()
+				.name("toolThrowMcpError")
+				.description("toolThrowMcpError description")
+				.inputSchema(emptyJsonSchema)
+				.build())
+			.callHandler((exchange, request) -> {
+				throw new McpError(
+						new McpSchema.JSONRPCResponse.JSONRPCError(50000, "test exception message", Map.of("a", "b")));
+			})
+			.build();
+
+		var mcpServer = prepareSyncServerBuilder().capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(tool1)
+			.build();
+
+		try (var mcpClient = clientBuilder.build()) {
+
+			InitializeResult initResult = mcpClient.initialize();
+			assertThat(initResult).isNotNull();
+
+			assertThat(mcpClient.listTools().tools()).contains(tool1.tool());
+			assertThatThrownBy(() -> mcpClient.callTool(new McpSchema.CallToolRequest("toolThrowMcpError", Map.of())))
+				.isInstanceOf(McpError.class)
+				.hasMessage("test exception message")
+				.satisfies(ex -> {
+					McpError mcpError = (McpError) ex;
+					assertThat(mcpError.getJsonRpcError()).isNotNull();
+					assertThat(mcpError.getJsonRpcError().code()).isEqualTo(50000);
+				});
+
+		}
+
+		mcpServer.close();
+	}
+
 }
diff --git a/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcStreamableIntegrationTests.java b/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcStreamableIntegrationTests.java
index 16012e7d9..a0367ca27 100644
--- a/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcStreamableIntegrationTests.java
+++ b/mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcStreamableIntegrationTests.java
@@ -3,32 +3,39 @@
  */
 package io.modelcontextprotocol.server;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-import java.time.Duration;
-
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.modelcontextprotocol.AbstractMcpClientServerIntegrationTests;
+import io.modelcontextprotocol.client.McpClient;
+import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
+import io.modelcontextprotocol.client.transport.WebClientStreamableHttpTransport;
+import io.modelcontextprotocol.server.McpServer.AsyncSpecification;
+import io.modelcontextprotocol.server.McpServer.SyncSpecification;
+import io.modelcontextprotocol.server.transport.WebMvcStreamableServerTransportProvider;
+import io.modelcontextprotocol.spec.McpError;
+import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+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.Timeout;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
 import org.springframework.web.servlet.function.RouterFunction;
 import org.springframework.web.servlet.function.ServerResponse;
+import reactor.core.scheduler.Schedulers;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
+import java.time.Duration;
+import java.util.Map;
 
-import io.modelcontextprotocol.AbstractMcpClientServerIntegrationTests;
-import io.modelcontextprotocol.client.McpClient;
-import io.modelcontextprotocol.client.transport.HttpClientStreamableHttpTransport;
-import io.modelcontextprotocol.client.transport.WebClientStreamableHttpTransport;
-import io.modelcontextprotocol.server.McpServer.AsyncSpecification;
-import io.modelcontextprotocol.server.McpServer.SyncSpecification;
-import io.modelcontextprotocol.server.transport.WebMvcStreamableServerTransportProvider;
-import reactor.core.scheduler.Schedulers;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 @Timeout(15)
 class WebMvcStreamableIntegrationTests extends AbstractMcpClientServerIntegrationTests {
@@ -139,4 +146,53 @@ protected void prepareClients(int port, String mcpEndpoint) {
 					.requestTimeout(Duration.ofHours(10)));
 	}
 
+	@ParameterizedTest(name = "{0} : {displayName} ")
+	@ValueSource(strings = { "httpclient", "webflux" })
+	void testToolCallThrowMcpError(String clientType) {
+		String emptyJsonSchema = """
+				{
+					"$schema": "http://json-schema.org/draft-07/schema#",
+					"type": "object",
+					"properties": {}
+				}
+				""";
+
+		var clientBuilder = clientBuilders.get(clientType);
+
+		McpServerFeatures.SyncToolSpecification tool1 = McpServerFeatures.SyncToolSpecification.builder()
+			.tool(Tool.builder()
+				.name("toolThrowMcpError")
+				.description("toolThrowMcpError description")
+				.inputSchema(emptyJsonSchema)
+				.build())
+			.callHandler((exchange, request) -> {
+				throw new McpError(
+						new McpSchema.JSONRPCResponse.JSONRPCError(50000, "test exception message", Map.of("a", "b")));
+			})
+			.build();
+
+		var mcpServer = prepareSyncServerBuilder().capabilities(ServerCapabilities.builder().tools(true).build())
+			.tools(tool1)
+			.build();
+
+		try (var mcpClient = clientBuilder.build()) {
+
+			InitializeResult initResult = mcpClient.initialize();
+			assertThat(initResult).isNotNull();
+
+			assertThat(mcpClient.listTools().tools()).contains(tool1.tool());
+			assertThatThrownBy(() -> mcpClient.callTool(new McpSchema.CallToolRequest("toolThrowMcpError", Map.of())))
+				.isInstanceOf(McpError.class)
+				.hasMessage("test exception message")
+				.satisfies(ex -> {
+					McpError mcpError = (McpError) ex;
+					assertThat(mcpError.getJsonRpcError()).isNotNull();
+					assertThat(mcpError.getJsonRpcError().code()).isEqualTo(50000);
+				});
+
+		}
+
+		mcpServer.close();
+	}
+
 }
diff --git a/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java b/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java
index ef7967c1e..098906c0d 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerSession.java
@@ -177,9 +177,16 @@ public Mono<Void> responseStream(McpSchema.JSONRPCRequest jsonrpcRequest, McpStr
 				.map(result -> new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, jsonrpcRequest.id(), result,
 						null))
 				.onErrorResume(e -> {
+					McpSchema.JSONRPCResponse.JSONRPCError error;
+					if (e instanceof McpError mcpError && mcpError.getJsonRpcError() != null) {
+						error = mcpError.getJsonRpcError();
+					}
+					else {
+						error = new McpSchema.JSONRPCResponse.JSONRPCError(McpSchema.ErrorCodes.INTERNAL_ERROR,
+								e.getMessage(), null);
+					}
 					var errorResponse = new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, jsonrpcRequest.id(),
-							null, new McpSchema.JSONRPCResponse.JSONRPCError(McpSchema.ErrorCodes.INTERNAL_ERROR,
-									e.getMessage(), null));
+							null, error);
 					return Mono.just(errorResponse);
 				})
 				.flatMap(transport::sendMessage)