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.NET: [Bug]: Provided Human in the loop sample does not seem to work anymore with RC1 #4144

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.NET: [Bug]: Provided Human in the loop sample does not seem to work anymore with RC1#4144
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#4800
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.NETUsage: [Issues, PRs], Target: .NetbugUsage: [Issues], Target: all issues (Legacy, prefer issue type: bug)

Description

@rwjdk
Rasmus Wulff Jensen (rwjdk)
opened on Feb 21, 2026

Description

In the repo, you have https://github.com/microsoft/agent-framework/tree/main/dotnet/samples/GettingStarted/Workflows/HumanInTheLoop/HumanInTheLoopBasic

Which is a Human in the Loop sample... This seems not to work anymore with RC1 (If you guess a number, the sample just ends with no feedback or giving user the option to retry)

I also have a similar Sample here: https://github.com/rwjdk/MicrosoftAgentFrameworkSamples/blob/main/src/Workflow.HumanInTheLoop/Program.cs , and there I just get a very un-descriptive error of

System.InvalidOperationException: 'Executor 'Evaluator and Hint-giver' cannot send messages of type 'FeedbackToUser'.'
Image

when run... This sample worked flawlessly pre RC1

Any hints as to what is going on here?

Code Sample



Error Messages / Stack Traces




Package Versions


RC1


.NET Version


.NET10


Additional Context


No response
Activity
  1. Rasmus Wulff Jensen (rwjdk)
    added the
    Bug
    issue type on Feb 21, 2026
  2. Rasmus Wulff Jensen (rwjdk)
    added 
    bugUsage: [Issues], Target: all issues (Legacy, prefer issue type: bug)
     
    .NETUsage: [Issues, PRs], Target: .Net
     on Feb 21, 2026
  3. Mark Wallace (markwallace-microsoft)
    added 
    triageUsage: [Issues], Target: All issues that still need to be triaged
     on Feb 21, 2026
  4. codehunter13 commented on Feb 22, 2026 
    @codehunter13
    codehunter13
    on Feb 22, 2026
    think i got the same error in my application. Also worked previously (with the change i converted it to the [MessageHandler] way).
    

    System.InvalidOperationException: Executor 'CodeGenerationOrchestrator' cannot send messages of type 'GSL.Dev.Agents.Executors.CodeGeneration.ReviewRequest'.
   at Microsoft.Agents.AI.Workflows.InProc.InProcessRunnerContext.SendMessageAsync(String sourceId, Object message, String targetId, CancellationToken cancellationToken)
   at GSL.Dev.Agents.Executors.CodeGeneration.CodeGenerationOrchestrator.HandleAsync(TestGenerationResult testResult, IWorkflowContext context, CancellationToken cancellationToken) in D:\projects\CodingAgent\GSL.Dev.Agents\Executors\CodeGeneration\CodeGenerationOrchestrator.cs:line 117
   at Microsoft.Agents.AI.Workflows.RouteBuilder.<>c__DisplayClass12_0`1.<<AddHandler>g__WrappedHandlerAsync|0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.Agents.AI.Workflows.Execution.MessageRouter.RouteMessageAsync(Object message, IWorkflowContext context, Boolean requireRoute, CancellationToken cancellationToken)

  5. Mark Wallace (markwallace-microsoft)
    added this to  Agent Frameworkon Feb 23, 2026
  6. Mark Wallace (markwallace-microsoft)
    assigned 
    Jacob Alber (lokitoth)
    on Feb 23, 2026
  7. Mark Wallace (markwallace-microsoft)
    added 
    v1.0
     and removed 
    triageUsage: [Issues], Target: All issues that still need to be triaged
     on Feb 23, 2026
  8. rogeriorfp commented on Feb 24, 2026 
    @rogeriorfp
    Rogério de F. Pereira (rogeriorfp)
    on Feb 24, 2026
    

    Description
    

    In the repo, you have https://github.com/microsoft/agent-framework/tree/main/dotnet/samples/GettingStarted/Workflows/HumanInTheLoop/HumanInTheLoopBasic
    

    Which is a Human in the Loop sample... This seems not to work anymore with RC1 (If you guess a number, the sample just ends with no feedback or giving user the option to retry)
    

    I also have a similar Sample here: https://github.com/rwjdk/MicrosoftAgentFrameworkSamples/blob/main/src/Workflow.HumanInTheLoop/Program.cs , and there I just get a very un-descriptive error of
    

    System.InvalidOperationException: 'Executor 'Evaluator and Hint-giver' cannot send messages of type 'FeedbackToUser'.'

    
Image
when run... This sample worked flawlessly pre RC1

    Any hints as to what is going on here?
    

    Code Sample
    

    Error Messages / Stack Traces
    

    Package Versions
    

    RC1
    

    .NET Version
    

    .NET10
    

    Additional Context
    

    No response
    

    

    For the first example, you can fix it by adding the attributes [YieldsOutput(typeof(string))] and [SendsMessage(typeof(NumberSignal))] to the JudgeExecutor class. For the second example, I haven’t tested it, but since it’s the same error, I believe adding the attributes [YieldsOutput(typeof(string))] and [SendsMessage(typeof(FeedbackToUser))] to the EvaluateAndHintExecutor class should resolve it.
    

    [YieldsOutput(typeof(string))]
[SendsMessage(typeof(NumberSignal))]
internal sealed class JudgeExecutor() : Executor<int>("Judge")
{
...
}
  9. rwjdk commented on Feb 24, 2026 
    @rwjdk
    Rasmus Wulff Jensen (rwjdk)
    on Feb 24, 2026
    Author
    Thanks... That works 🙌.
    

    Is what we just did a workaround or a mandatory part of workflow now (I did not see anything like this mentioned in any documentation)
  10. rogeriorfp commented on Feb 24, 2026 
    @rogeriorfp
    Rogério de F. Pereira (rogeriorfp)
    on Feb 24, 2026
    I’m not sure. I tried it after noticing the presence of another attribute, [MessageHandler], in a different example and I also didn’t see anything in the documentation.
  11. rogeriorfp commented on Feb 24, 2026 
    @rogeriorfp
    Rogério de F. Pereira (rogeriorfp)
    on Feb 24, 2026
    I believe this will become mandatory based on pull request #3792.
  12. Jacob Alber (lokitoth)
    moved this to Planned in  Agent Frameworkon Feb 25, 2026
  13. Peter Ibekwe (peibekwe)
    assigned 
    Peter Ibekwe (peibekwe)
     and unassigned 
    Jacob Alber (lokitoth)
    on Mar 2, 2026
  14. mfoosSit commented on Mar 6, 2026 
    @mfoosSit
    mfoosSit
    on Mar 6, 2026
    I got the same issue.
    
Image
    

    Unfortunatelly the workaround with
    
[YieldsOutput(typeof(string))] [SendsMessage(typeof(NumberSignal))] internal sealed class JudgeExecutor() : Executor<int>("Judge") ddnt solved it.
  15. rogeriorfp commented on Mar 6, 2026 
    @rogeriorfp
    Rogério de F. Pereira (rogeriorfp)
    on Mar 6, 2026
    mfoosSit If you use context.SendMessageAsync, you should annotate the class with the SendsMessage attribute, and the type passed to typeof must be the type expected by the next executor.
    

    You didn’t provide any code snippet, but based on the error message it will probably be:
    

    [SendsMessage(typeof(ChatMessage))]
  16. Peter Ibekwe (peibekwe)
    moved this from Planned to In Progress in  Agent Frameworkon Mar 18, 2026
  17. Peter Ibekwe (peibekwe)
    moved this from In Progress to In Review in  Agent Frameworkon Mar 19, 2026
  18. Peter Ibekwe (peibekwe)
    closed this as completedin #4800on Mar 20, 2026
  19. github-project-automation
    moved this from In Review to Done in  Agent Frameworkon Mar 20, 2026
  20. Evan Mattson (moonbox3)
    removed 
    v1.0
     on Jun 17, 2026
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