This repo has an example Gemini client at bin/workflow_client.dart, as well as a simple file system server at bin/file_system_server.dart.
This client accepts any number of STDIO servers to connect to via the --server <path> arguments, and is a good way to test out your servers.
For example, you can use the example file system server with it as follows:
dart bin/workflow_client.dart --server "dart bin/file_system_server.dart"
This client uses gemini to invoke tools, and requires a gemini api key.