diff --git a/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerTransportProvider.java b/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerTransportProvider.java
index 09fe9fb0e..4e9912db8 100644
--- a/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerTransportProvider.java
+++ b/mcp/src/main/java/io/modelcontextprotocol/spec/McpStreamableServerTransportProvider.java
@@ -66,4 +66,8 @@ default void close() {
 	 */
 	Mono<Void> closeGracefully();
 
+	@Override
+	default String protocolVersion() {
+		return "2025-03-26";
+	}
 }