Why i need a proto file or reflection to call grpc web?

[Lucas Löffel]

echo '{}' | evans --host xxx --port 3000 --web cli call mindful.earth.category.v1.CategoryService/BatchGetCategories

* one or more proto files, or gRPC reflection required

grpc-web has no reflection right?

evans --host xxx --port 3000 --web -r repl                                                                      
evans: failed to run REPL mode: failed to instantiate a new spec: failed to instantiate the spec: failed to list packages by gRPC reflection: failed to list services from reflection enabled gRPC server: failed to create a new client stream: failed to create a new transport stream: failed to dial to 'ws://xxx:3000/grpc.reflection.v1alpha.ServerReflection/ServerReflectionInfo': websocket: bad handshake

[ktr]

I can't know if the behavior is caused on Evans side. Please provide more information with the issue template.