Whenever I try to compile my MAUI project I get CS0246 Error

I'm trying to build a three piece Streaming Project in which I need to build an API that is already working, a Java App for Android that I haven't even started and this .NET MAUI using C# that is giving me headaches, whenever I run the command "dotnet build" I get the same error for multiple ViewModels:

Error CS0246: The name or type of the namespace "ICommandAttribute" can't be found or treated (missing using or assembly reference?)

This is my code:

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using PimStreamingApp.Maui.Services;

namespace PimStreamingApp.Maui.ViewModels;

public partial class LoginViewModel : ObservableObject
{
    private readonly IAuthService _authService;

    [ObservableProperty] private string email = "";
    [ObservableProperty] private string password = "";
    [ObservableProperty] private bool isBusy;

    public LoginViewModel(IAuthService authService)
    {
        _authService = authService;
    }

    [ICommand]
    private async Task LoginAsync()
    {
        if (IsBusy) 
            return;

        IsBusy = true;

        try
        {
            var token = await _authService.LoginAsync(Email, Password);

            if (!string.IsNullOrEmpty(token))
            {
                await Shell.Current.GoToAsync("//dashboard");
            }
            else
            {
                await Application.Current.MainPage.DisplayAlert("Erro", "Credenciais inválidas", "OK");
            }
        }
        finally
        {
            IsBusy = false;
        }
    }

    [ICommand]
    private async Task RegisterAsync()
    {
        // abre página de registro se existir
        await Application.Current.MainPage.DisplayAlert("Info", "Use o Swagger para registrar (ou implemente RegisterPage).", "OK");
    }
}

Right here is one of the view models I've built.

Any answer is helpful, thanks

The repo can be found at https://github.com/p3dromelo/PimStreamingApp.Maui if anyone wants to check it further.