diff --git a/pkgs/dart_mcp/example/simple_server.dart b/pkgs/dart_mcp/example/simple_server.dart
index 35522a95..abe3c72e 100644
--- a/pkgs/dart_mcp/example/simple_server.dart
+++ b/pkgs/dart_mcp/example/simple_server.dart
@@ -39,7 +39,7 @@ base class DartMCPServer extends MCPServer with ToolsSupport {
   @override
   FutureOr<InitializeResult> initialize(InitializeRequest request) {
     registerTool(
-      Tool(name: 'hello world', inputSchema: ObjectSchema()),
+      Tool(name: 'hello_world', inputSchema: ObjectSchema()),
       (_) => CallToolResult(content: [TextContent(text: 'hello world!')]),
     );
     return super.initialize(request);