More protected and public scoping for extending sync

and async servers and clients

Author: Scott Lewis

mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java

@@ -42,6 +42,7 @@
 import org.slf4j.LoggerFactory;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
+import reactor.util.context.ContextView;
 
 /**
  * The Model Context Protocol (MCP) client implementation that provides asynchronous
@@ -317,13 +318,20 @@ public McpAsyncClient(McpClientTransport transport, Duration requestTimeout, Dur
 		};
 
 		this.initializer = new LifecycleInitializer(clientCapabilities, clientInfo, transport.protocolVersions(),
-				initializationTimeout, ctx -> new McpClientSession(requestTimeout, transport, requestHandlers,
-						notificationHandlers, con -> con.contextWrite(ctx)),
+				initializationTimeout,
+				ctx -> buildClientSession(requestTimeout, transport, requestHandlers, notificationHandlers, ctx),
 				postInitializationHook);
 
 		this.transport.setExceptionHandler(this.initializer::handleException);
 	}
 
+	protected McpClientSession buildClientSession(Duration requestTimeout, McpClientTransport transport,
+			Map<String, RequestHandler<?>> requestHandlers, Map<String, NotificationHandler> notificationHandlers,
+			ContextView ctx) {
+		return new McpClientSession(requestTimeout, transport, requestHandlers, notificationHandlers,
+				con -> con.contextWrite(ctx));
+	}
+
 	/**
 	 * Get the current initialization result.
 	 * @return the initialization result.

mcp-core/src/main/java/io/modelcontextprotocol/client/McpSyncClient.java

@@ -64,7 +64,7 @@ public class McpSyncClient implements AutoCloseable {
 	// is not a requirement?
 	private static final long DEFAULT_CLOSE_TIMEOUT_MS = 10_000L;
 
-	private final McpAsyncClient delegate;
+	protected final McpAsyncClient delegate;
 
 	private final Supplier<McpTransportContext> contextProvider;