Improve MCP SSE URL configuration documentation and examples

Fixes spring-projects#3938

Signed-off-by: Mattia Pasetto <[email protected]>

Author: wilocu

auto-configurations/mcp/spring-ai-autoconfigure-mcp-client-common/src/main/java/org/springframework/ai/mcp/client/common/autoconfigure/properties/McpSseClientProperties.java

@@ -29,13 +29,27 @@
  * Each connection is configured with a URL endpoint for SSE communication.
  *
  * <p>
- * Example configuration: <pre>
+ * Example configurations: <pre>
+ * # Simple configuration with default SSE endpoint (/sse)
  * spring.ai.mcp.client.sse:
  *   connections:
  *     server1:
- *       url: http://localhost:8080/events
- *     server2:
- *       url: http://otherserver:8081/events
+ *       url: http://localhost:8080
+ *
+ * # Custom SSE endpoints - split complex URLs correctly
+ * spring.ai.mcp.client.sse:
+ *   connections:
+ *     mcp-hub:
+ *       url: http://localhost:3000
+ *       sse-endpoint: /mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01
+ *     custom-server:
+ *       url: http://api.example.com
+ *       sse-endpoint: /v1/mcp/events?token=abc123&format=json
+ *
+ * # How to split a full URL:
+ * # Full URL: http://localhost:3000/mcp-hub/sse/token123
+ * # Split as:  url: http://localhost:3000
+ * #           sse-endpoint: /mcp-hub/sse/token123
  * </pre>
  *
  * @author Christian Tzolov

auto-configurations/mcp/spring-ai-autoconfigure-mcp-client-common/src/test/java/org/springframework/ai/mcp/client/common/autoconfigure/properties/McpSseClientPropertiesTests.java

@@ -283,6 +283,20 @@ void specialCharactersInSseEndpoint() {
 			});
 	}
 
+	@Test
+	void mcpHubStyleUrlWithTokenPath() {
+		this.contextRunner.withPropertyValues("spring.ai.mcp.client.sse.connections.mcp-hub.url=http://localhost:3000",
+				"spring.ai.mcp.client.sse.connections.mcp-hub.sse-endpoint=/mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01")
+			.run(context -> {
+				McpSseClientProperties properties = context.getBean(McpSseClientProperties.class);
+				assertThat(properties.getConnections()).hasSize(1);
+				assertThat(properties.getConnections()).containsKey("mcp-hub");
+				assertThat(properties.getConnections().get("mcp-hub").url()).isEqualTo("http://localhost:3000");
+				assertThat(properties.getConnections().get("mcp-hub").sseEndpoint())
+					.isEqualTo("/mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01");
+			});
+	}
+
 	@Configuration
 	@EnableConfigurationProperties(McpSseClientProperties.class)
 	static class TestConfiguration {

auto-configurations/mcp/spring-ai-autoconfigure-mcp-client-httpclient/src/main/java/org/springframework/ai/mcp/client/httpclient/autoconfigure/SseHttpClientTransportAutoConfiguration.java

@@ -109,26 +109,38 @@ public List<NamedClientMcpTransport> sseHttpClientTransports(McpSseClientConnect
 		List<NamedClientMcpTransport> sseTransports = new ArrayList<>();
 
 		for (Map.Entry<String, SseParameters> serverParameters : connectionDetails.getConnections().entrySet()) {
-
-			String baseUrl = serverParameters.getValue().url();
-			String sseEndpoint = serverParameters.getValue().sseEndpoint() != null
-					? serverParameters.getValue().sseEndpoint() : "/sse";
-			HttpClientSseClientTransport.Builder transportBuilder = HttpClientSseClientTransport.builder(baseUrl)
-				.sseEndpoint(sseEndpoint)
-				.clientBuilder(HttpClient.newBuilder())
-				.jsonMapper(new JacksonMcpJsonMapper(objectMapper));
-
-			asyncHttpRequestCustomizer.ifUnique(transportBuilder::asyncHttpRequestCustomizer);
-			syncHttpRequestCustomizer.ifUnique(transportBuilder::httpRequestCustomizer);
-			if (asyncHttpRequestCustomizer.getIfUnique() != null && syncHttpRequestCustomizer.getIfUnique() != null) {
-				logger.warn("Found beans of type %s and %s. Using %s.".formatted(
-						McpAsyncHttpClientRequestCustomizer.class.getSimpleName(),
-						McpSyncHttpClientRequestCustomizer.class.getSimpleName(),
-						McpSyncHttpClientRequestCustomizer.class.getSimpleName()));
+			String connectionName = serverParameters.getKey();
+			SseParameters params = serverParameters.getValue();
+
+			String baseUrl = params.url();
+			String sseEndpoint = params.sseEndpoint() != null ? params.sseEndpoint() : "/sse";
+			if (baseUrl == null || baseUrl.trim().isEmpty()) {
+				throw new IllegalArgumentException("SSE connection '" + connectionName
+						+ "' requires a 'url' property. Example: url: http://localhost:3000");
 			}
 
-			HttpClientSseClientTransport transport = transportBuilder.build();
-			sseTransports.add(new NamedClientMcpTransport(serverParameters.getKey(), transport));
+			try {
+				var transportBuilder = HttpClientSseClientTransport.builder(baseUrl)
+					.sseEndpoint(sseEndpoint)
+					.clientBuilder(HttpClient.newBuilder())
+					.jsonMapper(new JacksonMcpJsonMapper(objectMapper));
+
+				asyncHttpRequestCustomizer.ifUnique(transportBuilder::asyncHttpRequestCustomizer);
+				syncHttpRequestCustomizer.ifUnique(transportBuilder::httpRequestCustomizer);
+				if (asyncHttpRequestCustomizer.getIfUnique() != null
+						&& syncHttpRequestCustomizer.getIfUnique() != null) {
+					logger.warn("Found beans of type %s and %s. Using %s.".formatted(
+							McpAsyncHttpClientRequestCustomizer.class.getSimpleName(),
+							McpSyncHttpClientRequestCustomizer.class.getSimpleName(),
+							McpSyncHttpClientRequestCustomizer.class.getSimpleName()));
+				}
+				sseTransports.add(new NamedClientMcpTransport(connectionName, transportBuilder.build()));
+			}
+			catch (Exception e) {
+				throw new IllegalArgumentException("Failed to create SSE transport for connection '" + connectionName
+						+ "'. Check URL splitting: url='" + baseUrl + "', sse-endpoint='" + sseEndpoint
+						+ "'. Full URL should be split as: url=http://host:port, sse-endpoint=/path/to/endpoint", e);
+			}
 		}
 
 		return sseTransports;

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/mcp/mcp-client-boot-starter-docs.adoc

@@ -241,7 +241,7 @@ Properties for Server-Sent Events (SSE) transport are prefixed with `spring.ai.m
 |`/sse`
 |===
 
-Example configuration:
+Example configurations:
 [source,yaml]
 ----
 spring:
@@ -250,13 +250,88 @@ spring:
       client:
         sse:
           connections:
+            # Simple configuration using default /sse endpoint
             server1:
               url: http://localhost:8080
+            # Custom SSE endpoint
             server2:
               url: http://otherserver:8081
               sse-endpoint: /custom-sse
+            # Complex URL with path and token (like MCP Hub)
+            mcp-hub:
+              url: http://localhost:3000
+              sse-endpoint: /mcp-hub/sse/cf9ec4527e3c4a2cbb149a85ea45ab01
+            # SSE endpoint with query parameters
+            api-server:
+              url: https://api.example.com
+              sse-endpoint: /v1/mcp/events?token=abc123&format=json
 ----
 
+==== URL Splitting Guidelines
+
+When you have a full SSE URL, split it into base URL and endpoint path:
+
+[cols="2,2"]
+|===
+|Full URL |Configuration
+
+|`\http://localhost:3000/mcp-hub/sse/token123`
+|`url: http://localhost:3000` +
+`sse-endpoint: /mcp-hub/sse/token123`
+
+|`\https://api.service.com/v2/events?key=secret`
+|`url: https://api.service.com` +
+`sse-endpoint: /v2/events?key=secret`
+
+|`\http://localhost:8080/sse`
+|`url: http://localhost:8080` +
+`sse-endpoint: /sse` (or omit for default)
+|===
+
+==== Troubleshooting SSE Connections
+
+*404 Not Found Errors:*
+
+* Verify URL splitting: ensure the base `url` contains only the scheme, host, and port
+* Check the `sse-endpoint` starts with `/` and includes the full path and query parameters
+* Test the full URL directly in a browser or curl to confirm it's accessible
+
+=== Streamable Http Transport Properties
+
+Properties for Streamable Http transport are prefixed with `spring.ai.mcp.client.streamable-http`:
+
+[cols="3,4,3"]
+|===
+|Property |Description | Default Value
+
+|`connections`
+|Map of named Streamable Http connection configurations
+|-
+
+|`connections.[name].url`
+|Base URL endpoint for Streamable-Http communication with the MCP server
+|-
+
+|`connections.[name].endpoint`
+|the streamable-http endpoint (as url suffix) to use for the connection
+|`/mcp`
+|===
+
+Example configuration:
+[source,yaml]
+----
+spring:
+  ai:
+    mcp:
+      client:
+        streamable-http:
+          connections:
+            server1:
+              url: http://localhost:8080
+            server2:
+              url: http://otherserver:8081
+              endpoint: /custom-sse
+----
 
 == Features