.NET: [Question] [dotnet][workflows] [MessageHandler] partial Executor requires manual ConfigureProtocol (CS0534)

[toledo85]

Hi team,

I’m using Microsoft.Agents.AI.Workflows 1.5.0 and following the docs pattern with [MessageHandler] on a partial class inheriting from Executor("...").

Build fails with:

CS0534: 'AddTenExecutor' does not implement inherited abstract member 'Executor.ConfigureProtocol(ProtocolBuilder)'

Minimal repro:

using Microsoft.Agents.AI.Workflows;

namespace AgentFrameworkLearning;

public sealed partial class AddTenExecutor() : Executor("SourceExecutor") {
    [MessageHandler]
    private ValueTask<int> HandleAsync(int input, IWorkflowContext context, CancellationToken ct) {
        return ValueTask.FromResult(input + 10);
    }
}

Environment:

• Microsoft.Agents.AI.Workflows 1.5.0
• Reproduced on net10.0 and net9.0
• Command: dotnet build -nodeReuse:false /p:UseSharedCompilation=false

What I tested:

• Clean build
• No duplicate using
• Separate file for executor class

Manual ConfigureProtocol + ConfigureRoutes(AddHandler) works as a workaround, so the workflow logic itself is valid.

Is additional setup required for [MessageHandler] source generation, or is this a known issue?
Could you share a minimal working example on 1.5.0 that uses [MessageHandler] without manual ConfigureProtocol?

[lokitoth]

Hi @toledo85, thanks for your question.

It seems like you might not have the SourceGenerator package referenced in your project. Do you have something like:

<PackageReference Include="Microsoft.Agents.AI.Workflows.Generators" Version="1.6.1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>