extra impl is done

sandbox/GeneratorSandbox/Filters.cs

@@ -60,15 +60,12 @@ public override async Task InvokeAsync(ConsoleAppContext context, CancellationTo
     }
 }
 
-internal class PreventMultipleInstanceFilter(ConsoleAppFilter next) : ConsoleAppFilter(next)
+internal class PreventMultipleSameCommandInvokeFilter(ConsoleAppFilter next) : ConsoleAppFilter(next)
 {
     public override async Task InvokeAsync(ConsoleAppContext context, CancellationToken cancellationToken)
     {
-        // allow another command
-        // prevent: location + command
         var basePath = Assembly.GetEntryAssembly()?.Location.Replace(Path.DirectorySeparatorChar, '_');
-
-        var mutexKey = $"{basePath}$$${context.CommandName}";
+        var mutexKey = $"{basePath}$$${context.CommandName}"; // lock per command-name
 
         using var mutex = new Mutex(true, mutexKey, out var createdNew);
         if (!createdNew)

tests/ConsoleAppFramework.GeneratorTests/ConsoleAppContextTest.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit.Abstractions;
+
+namespace ConsoleAppFramework.GeneratorTests;
+
+public class ConsoleAppContextTest(ITestOutputHelper output)
+{
+    VerifyHelper verifier = new VerifyHelper(output, "CAF");
+
+    [Fact]
+    public void ForLambda()
+    {
+        verifier.Execute("""
+ConsoleApp.Run(args, (ConsoleAppContext ctx) => { Console.Write(ctx.Arguments.Length); });
+""", args: "", expected: "0");
+    }
+
+    [Fact]
+    public void ForMethod()
+    {
+        verifier.Execute("""
+var builder = ConsoleApp.Create();
+
+builder.UseFilter<StateFilter>();
+
+builder.Add("", Hello);
+
+builder.Run(args);
+
+void Hello(ConsoleAppContext ctx)
+{
+    Console.Write(ctx.State);
+}
+
+internal class StateFilter(ConsoleAppFilter next)
+    : ConsoleAppFilter(next)
+{
+    public override Task InvokeAsync(ConsoleAppContext context,CancellationToken cancellationToken)
+    {
+        Console.Write(1);
+        return Next.InvokeAsync(context with { State = 2 }, cancellationToken);
+    }
+}
+""", args: "", expected: "12");
+    }
+}