diff --git a/src/Flowsharp.Core/Flowsharp.Core.csproj b/src/Flowsharp.Core/Flowsharp.Core.csproj
index 354fcbfd2..463bd2ac7 100644
--- a/src/Flowsharp.Core/Flowsharp.Core.csproj
+++ b/src/Flowsharp.Core/Flowsharp.Core.csproj
@@ -15,6 +15,7 @@
     <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="2.1.1" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="2.1.1" />
     <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+    <PackageReference Include="YamlDotNet.NetStandard" Version="4.0.0" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Flowsharp.Core/Serialization/Formatters/YamlTokenFormatter.cs b/src/Flowsharp.Core/Serialization/Formatters/YamlTokenFormatter.cs
new file mode 100644
index 000000000..ff3196d5e
--- /dev/null
+++ b/src/Flowsharp.Core/Serialization/Formatters/YamlTokenFormatter.cs
@@ -0,0 +1,29 @@
+using System.Dynamic;
+using Flowsharp.Services;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using Newtonsoft.Json.Linq;
+using YamlDotNet.Serialization;
+
+namespace Flowsharp.Serialization.Formatters
+{
+    public class YamlTokenFormatter : ITokenFormatter
+    {
+        public YamlTokenFormatter()
+        {
+        }
+
+        public string ToString(JToken token)
+        {
+            var expConverter = new ExpandoObjectConverter();
+            var jsonString = token.ToString(Formatting.None);
+            var expandoObject = JsonConvert.DeserializeObject<ExpandoObject>(jsonString, expConverter);
+            var serializer = new SerializerBuilder().Build();
+            var yaml = serializer.Serialize(expandoObject);
+
+            return yaml;
+        }
+        
+        public JToken FromString(string data) => JToken.Parse(data);
+    }
+}
\ No newline at end of file
diff --git a/src/Flowsharp.Samples.Console/Flowchart1.yaml b/src/Flowsharp.Samples.Console/Flowchart1.yaml
deleted file mode 100644
index e69de29bb..000000000
diff --git a/src/Flowsharp.Samples.Console/Flowsharp.Samples.Console.csproj b/src/Flowsharp.Samples.Console/Flowsharp.Samples.Console.csproj
index 366c51221..61641f168 100644
--- a/src/Flowsharp.Samples.Console/Flowsharp.Samples.Console.csproj
+++ b/src/Flowsharp.Samples.Console/Flowsharp.Samples.Console.csproj
@@ -13,6 +13,8 @@
   <ItemGroup>
     <None Remove="SampleWorkflow.json" />
     <EmbeddedResource Include="SampleWorkflow.json" />
+    <None Remove="SampleWorkflow.yaml" />
+    <EmbeddedResource Include="SampleWorkflow.yaml" />
   </ItemGroup>
 
 </Project>
diff --git a/src/Flowsharp.Samples.Console/Program.cs b/src/Flowsharp.Samples.Console/Program.cs
index 2a6931903..f4b0d3a41 100644
--- a/src/Flowsharp.Samples.Console/Program.cs
+++ b/src/Flowsharp.Samples.Console/Program.cs
@@ -24,7 +24,8 @@ namespace Flowsharp.Samples.Console
                 .AddSingleton<IWorkflowInvoker, WorkflowInvoker>()
                 .AddSingleton<IActivityInvoker, ActivityInvoker>()
                 .AddSingleton<IWorkflowSerializer, WorkflowSerializer>()
-                .AddSingleton<ITokenFormatter, JsonTokenFormatter>()
+                //.AddSingleton<ITokenFormatter, JsonTokenFormatter>()
+                .AddSingleton<ITokenFormatter, YamlTokenFormatter>()
                 .AddSingleton<IWorkflowTokenizer, WorkflowTokenizer>()
                 .AddSingleton<ITokenizerInvoker, TokenizerInvoker>()
                 .AddSingleton<ITokenizer, DefaultTokenizer>()
@@ -43,7 +44,8 @@ namespace Flowsharp.Samples.Console
                 .AddSingleton<FileBasedWorkflowProgramLongRunning>();
 
             var serviceProvider = services.BuildServiceProvider();
-            var program = serviceProvider.GetRequiredService<FileBasedWorkflowProgramLongRunning>();
+            var program = serviceProvider.GetRequiredService<AdditionWorkflowProgramLongRunning>();
+            //var program = serviceProvider.GetRequiredService<FileBasedWorkflowProgramLongRunning>();
             
             await program.RunAsync(CancellationToken.None);
         }
diff --git a/src/Flowsharp.Samples.Console/SampleWorkflow.yaml b/src/Flowsharp.Samples.Console/SampleWorkflow.yaml
new file mode 100644
index 000000000..e83442b5f
--- /dev/null
+++ b/src/Flowsharp.Samples.Console/SampleWorkflow.yaml
@@ -0,0 +1,153 @@
+status: Idle
+activities:
+- id: 1
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: Welcome to Addition Workflow - Long Running edition!
+- id: 2
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: Let's run a long-running program.
+- id: 3
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: 'Enter first value:'
+- id: 4
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: 'Enter second value:'
+- id: 5
+  name: WriteLine
+  textExpression:
+      syntax: JavaScript
+      expression: >-
+          var x = workflow.getVariable('x');
+
+          var y = workflow.getVariable('y');
+
+          var sum = parseInt(x) + parseInt(y);
+
+          x + ' + ' + y + ' = ' + sum;
+- id: 6
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: Try again? (Y/N)
+- id: 7
+  name: WriteLine
+  textExpression:
+      syntax: PlainText
+      expression: Bye!
+- id: 8
+  name: ReadLine
+  argumentName: x
+- id: 9
+  name: ReadLine
+  argumentName: y
+- id: 10
+  name: ReadLine
+  argumentName: tryAgain
+- id: 11
+  name: SetVariable
+  variableName: x
+  valueExpression:
+      syntax: JavaScript
+      expression: workflow.getLastResult()
+- id: 12
+  name: SetVariable
+  variableName: y
+  valueExpression:
+      syntax: JavaScript
+      expression: workflow.getLastResult()
+- id: 13
+  name: SetVariable
+  variableName: tryAgain
+  valueExpression:
+      syntax: JavaScript
+      expression: "'y' === workflow.getLastResult().toLowerCase()"
+- id: 14
+  name: IfElse
+  conditionExpression:
+      syntax: JavaScript
+      expression: workflow.getVariable('tryAgain')
+connections:
+- source:
+      activityId: 1
+      endpoint:
+  target:
+      activityId: 2
+- source:
+      activityId: 2
+      endpoint:
+  target:
+      activityId: 3
+- source:
+      activityId: 3
+      endpoint:
+  target:
+      activityId: 8
+- source:
+      activityId: 8
+      endpoint:
+  target:
+      activityId: 11
+- source:
+      activityId: 11
+      endpoint:
+  target:
+      activityId: 4
+- source:
+      activityId: 4
+      endpoint:
+  target:
+      activityId: 9
+- source:
+      activityId: 9
+      endpoint:
+  target:
+      activityId: 12
+- source:
+      activityId: 12
+      endpoint:
+  target:
+      activityId: 5
+- source:
+      activityId: 5
+      endpoint:
+  target:
+      activityId: 6
+- source:
+      activityId: 6
+      endpoint:
+  target:
+      activityId: 10
+- source:
+      activityId: 10
+      endpoint:
+  target:
+      activityId: 13
+- source:
+      activityId: 13
+      endpoint:
+  target:
+      activityId: 14
+- source:
+      activityId: 14
+      endpoint: True
+  target:
+      activityId: 3
+- source:
+      activityId: 14
+      endpoint: False
+  target:
+      activityId: 7
+haltedActivities: []
+scopes:
+- id: 1
+  variables: []
+  lastResult:
+currentScope: 1