Read TrainExceptionData from Exception.Data in AddException

src/Trax.Effect/Models/Metadata/Metadata.cs

@@ -399,37 +399,38 @@ public static Metadata Create(CreateMetadata metadata)
     /// </remarks>
     public Unit AddException(Exception trainException)
     {
+        // Priority 1: Structured data attached to the exception object (local execution)
+        if (trainException.Data["TrainExceptionData"] is TrainExceptionData data)
+        {
+            FailureException = data.Type;
+            FailureReason = data.Message;
+            FailureJunction = data.Junction;
+            StackTrace = data.StackTrace ?? trainException.StackTrace;
+            return Unit.Default;
+        }
+
+        // Priority 2: JSON-serialized TrainExceptionData in the message (remote execution / legacy)
         try
         {
-            var deserializedException = JsonSerializer.Deserialize<TrainExceptionData>(
+            var deserialized = JsonSerializer.Deserialize<TrainExceptionData>(
                 trainException.Message
             );
-
-            if (deserializedException == null)
+            if (deserialized != null)
             {
-                FailureException = trainException.GetType().Name;
-                FailureReason = trainException.Message;
-                FailureJunction = "TrainException";
-                StackTrace = trainException.StackTrace;
+                FailureException = deserialized.Type;
+                FailureReason = deserialized.Message;
+                FailureJunction = deserialized.Junction;
+                StackTrace = deserialized.StackTrace ?? trainException.StackTrace;
+                return Unit.Default;
             }
-            else
-            {
-                FailureException = deserializedException.Type;
-                FailureReason = deserializedException.Message;
-                FailureJunction = deserializedException.Junction;
-                StackTrace = trainException.StackTrace;
-            }
-
-            return Unit.Default;
-        }
-        catch (Exception)
-        {
-            FailureException = trainException.GetType().Name;
-            FailureReason = trainException.Message;
-            FailureJunction = "TrainException";
-            StackTrace = trainException.StackTrace;
         }
+        catch { }
 
+        // Priority 3: Plain exception (no Trax context)
+        FailureException = trainException.GetType().Name;
+        FailureReason = trainException.Message;
+        FailureJunction = "TrainException";
+        StackTrace = trainException.StackTrace;
         return Unit.Default;
     }
 

tests/Trax.Effect.Tests.Broadcaster/UnitTests/BroadcastLifecycleHookTests.cs

@@ -1,6 +1,7 @@
 using System.Reflection;
 using FluentAssertions;
 using NSubstitute;
+using Trax.Core.Exceptions;
 using Trax.Effect.Enums;
 using Trax.Effect.Extensions;
 using Trax.Effect.Models.Metadata;
@@ -203,6 +204,65 @@ await _hook.OnFailed(
         captured.FailureReason.Should().Be("something broke");
     }
 
+    [Test]
+    public async Task OnFailed_WithTrainExceptionData_BroadcastsJunctionAndReason()
+    {
+        var metadata = CreateMetadata(TrainState.Failed);
+
+        var exception = new InvalidOperationException("connection refused");
+        exception.Data["TrainExceptionData"] = new TrainExceptionData
+        {
+            TrainName = "TestTrain",
+            TrainExternalId = "ext-1",
+            Type = "InvalidOperationException",
+            Junction = "DatabaseJunction",
+            Message = "connection refused",
+            StackTrace = "at App.DatabaseJunction.Run()",
+        };
+        metadata.AddException(exception);
+
+        TrainLifecycleEventMessage? captured = null;
+        await _broadcaster.PublishAsync(
+            Arg.Do<TrainLifecycleEventMessage>(m => captured = m),
+            Arg.Any<CancellationToken>()
+        );
+
+        await _hook.OnFailed(metadata, exception, CancellationToken.None);
+
+        captured!.FailureJunction.Should().Be("DatabaseJunction");
+        captured.FailureReason.Should().Be("connection refused");
+    }
+
+    [Test]
+    public async Task OnFailed_FailureReasonIsNotJsonBlob()
+    {
+        var metadata = CreateMetadata(TrainState.Failed);
+
+        var exception = new HttpRequestException("500 Internal Server Error");
+        exception.Data["TrainExceptionData"] = new TrainExceptionData
+        {
+            TrainName = "TestTrain",
+            TrainExternalId = "ext-1",
+            Type = "HttpRequestException",
+            Junction = "ApiCallJunction",
+            Message = "500 Internal Server Error",
+            StackTrace = "at App.ApiCallJunction.Run()",
+        };
+        metadata.AddException(exception);
+
+        TrainLifecycleEventMessage? captured = null;
+        await _broadcaster.PublishAsync(
+            Arg.Do<TrainLifecycleEventMessage>(m => captured = m),
+            Arg.Any<CancellationToken>()
+        );
+
+        await _hook.OnFailed(metadata, exception, CancellationToken.None);
+
+        // The broadcaster should not receive a JSON blob as the failure reason
+        captured!.FailureReason.Should().NotStartWith("{");
+        captured.FailureReason.Should().Be("500 Internal Server Error");
+    }
+
     [Test]
     public async Task PassesCancellationTokenToBroadcaster()
     {