Add ActivitySource and Logging

AuthorAgent.cs

@@ -1,5 +1,7 @@
+using System.Diagnostics;
 using Microsoft.Agents.AI;
 using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
 
 namespace BlogWriter;
 
@@ -13,8 +15,16 @@ public class AuthorAgent : IAuthorAgent
 {
     private readonly ChatClientAgent _agent;
 
-    public AuthorAgent(IChatClient llm, ChatOptions chatOptions)
+    // Emits a span per draft creation/revision. Activated by the ActivityListener
+    // registered in Program.cs (or an OpenTelemetry TracerProvider).
+    private static readonly ActivitySource s_activitySource = new("BlogWriter.AuthorAgent");
+
+    private readonly ILogger<AuthorAgent> _logger;
+
+    public AuthorAgent(IChatClient llm, ChatOptions chatOptions, ILogger<AuthorAgent> logger)
     {
+        _logger = logger;
+
         _agent = new ChatClientAgent(llm, new ChatClientAgentOptions
         {
             Name = "Author",
@@ -25,10 +35,14 @@ public AuthorAgent(IChatClient llm, ChatOptions chatOptions)
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
         });
+        _logger.LogInformation("AuthorAgent initialized.");
     }
 
     public async Task<string> InvokeAsync(ResearchState state)
     {
+        using Activity? activity = s_activitySource.StartActivity("Author.Invoke");
+        activity?.SetTag("blog.revision", state.RevisionNumber);
+
         List<string> research = state.ResearchFindings;
         string researchText = research.Count > 0 ? string.Join("\n\n", research) : "No research available.";
 

BlogWorkflow.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using Microsoft.Agents.AI.Workflows;
 
 namespace BlogWriter;
@@ -16,8 +17,15 @@ public class BlogWorkflow(
     IAuthorAgent author,
     IReviewerAgent reviewer) : IBlogWorkflow
 {
+    // Emits the root span for a workflow run. Activated by the ActivityListener
+    // registered in Program.cs (or an OpenTelemetry TracerProvider).
+    private static readonly ActivitySource s_activitySource = new("BlogWriter.Workflow");
+
     public async Task<ResearchState> RunAsync(ResearchState state)
     {
+        using Activity? activity = s_activitySource.StartActivity("Workflow.Run");
+        activity?.SetTag("blog.topic", state.MainTask);
+
         var bloggerExecutor = new BloggerExecutor(blogger);
         var researcherExecutor = new ResearcherExecutor(researcher);
         var authorExecutor = new AuthorExecutor(author);

BlogWriter.csproj

@@ -17,6 +17,8 @@
     </PackageReference>
     <PackageReference Include="Microsoft.Extensions.AI" Version="10.7.0" />
     <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.7.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="10.0.10" />
     <PackageReference Include="OpenAI" Version="2.11.0" />
   </ItemGroup>
 

BloggerAgent.cs

@@ -1,6 +1,8 @@
+using System.Diagnostics;
 using System.Text.Json;
 using Microsoft.Agents.AI;
 using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
 
 namespace BlogWriter;
 
@@ -22,8 +24,16 @@ public class BloggerAgent : IBloggerAgent
     // generated schema regardless of naming policy.
     private readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);
 
-    public BloggerAgent(IChatClient llm, ChatOptions chatOptions)
+    // Emits a span per Blogger decision. Activated by the ActivityListener
+    // registered in Program.cs (or an OpenTelemetry TracerProvider).
+    private static readonly ActivitySource s_activitySource = new("BlogWriter.BloggerAgent");
+
+    private readonly ILogger<BloggerAgent> _logger;
+
+    public BloggerAgent(IChatClient llm, ChatOptions chatOptions, ILogger<BloggerAgent> logger)
     {
+        _logger = logger;
+
         _agent = new ChatClientAgent(llm, new ChatClientAgentOptions
         {
             Name = "Blogger",
@@ -34,10 +44,14 @@ public BloggerAgent(IChatClient llm, ChatOptions chatOptions)
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
         });
+        _logger.LogInformation("BloggerAgent initialized.");
     }
 
     public async Task<BloggerDecision> InvokeAsync(ResearchState state)
     {
+        using Activity? activity = s_activitySource.StartActivity("Blogger.Invoke");
+        activity?.SetTag("blog.revision", state.RevisionNumber);
+
         List<string> research = state.ResearchFindings;
         string researchText = research.Count > 0 ? string.Join("\n", research) : "No research yet.";
         int revision = state.RevisionNumber;

Program.cs

@@ -1,9 +1,11 @@
 using System.ClientModel;
+using System.Diagnostics;
 using System.Net.Http.Headers;
 using System.Net.Http.Json;
 using System.Text.Json;
 using BlogWriter;
 using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
 using OpenAI;
 
 const string fileName = "config.json";
@@ -73,12 +75,29 @@
     description: "A search engine optimized for comprehensive, accurate, and trusted results.");
 
 // Creating a callable object
-var bloggerAgent = new BloggerAgent(llm, chatOptions);
-var researcherAgent = new ResearcherAgent(llm, chatOptions, tavilyTool);
-var authorAgent = new AuthorAgent(llm, chatOptions);
-var reviewerAgent = new ReviewerAgent(llm, chatOptions);
+using ILoggerFactory loggerFactory = LoggerFactory.Create(builder => builder.AddConsole());
+
+var bloggerAgent = new BloggerAgent(llm, chatOptions, loggerFactory.CreateLogger<BloggerAgent>());
+var researcherAgent = new ResearcherAgent(llm, chatOptions, tavilyTool, loggerFactory.CreateLogger<ResearcherAgent>());
+var authorAgent = new AuthorAgent(llm, chatOptions, loggerFactory.CreateLogger<AuthorAgent>());
+var reviewerAgent = new ReviewerAgent(llm, chatOptions, loggerFactory.CreateLogger<ReviewerAgent>());
 var app = new BlogWorkflow(bloggerAgent, researcherAgent, authorAgent, reviewerAgent);
 
+// Distributed tracing: an ActivityListener activates every "BlogWriter.*"
+// ActivitySource in the app (agents + workflow) and writes span start/stop to
+// the console. Swap this listener for OpenTelemetry's TracerProvider (and chain
+// IChatClient.UseOpenTelemetry() above) to export the same spans instead.
+var appActivitySource = new ActivitySource("BlogWriter.Program");
+
+ActivitySource.AddActivityListener(new ActivityListener
+{
+    ShouldListenTo = source => source.Name.StartsWith("BlogWriter", StringComparison.Ordinal),
+    Sample = (ref ActivityCreationOptions<ActivityContext> _) => ActivitySamplingResult.AllData,
+    ActivityStarted = activity => Console.WriteLine($"[trace] \u2192 {activity.DisplayName}"),
+    ActivityStopped = activity =>
+        Console.WriteLine($"[trace] \u2190 {activity.DisplayName} ({activity.Duration.TotalMilliseconds:F0} ms)")
+});
+
 Console.Write("Enter your topic: ");
 string topic = Console.ReadLine() ?? string.Empty;
 
@@ -88,7 +107,12 @@
     MainTask = topic
 };
 
-ResearchState result = await app.RunAsync(initialState);
+ResearchState result;
+using (Activity? runActivity = appActivitySource.StartActivity("BlogWriter.Run"))
+{
+    runActivity?.SetTag("blog.topic", topic);
+    result = await app.RunAsync(initialState);
+}
 
 Console.WriteLine("\n========== RESULTS ==========");
 Console.WriteLine($"Task: {result.MainTask}");

ResearcherAgent.cs

@@ -1,5 +1,7 @@
+using System.Diagnostics;
 using Microsoft.Agents.AI;
 using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
 
 namespace BlogWriter;
 
@@ -17,8 +19,16 @@ public class ResearcherAgent : IResearcherAgent
     // per-call behaviour while gaining tool-calling for free.
     private readonly ChatClientAgent _agent;
 
-    public ResearcherAgent(IChatClient llm, ChatOptions chatOptions, AIFunction tavilyTool)
+    // Emits a span per research turn. Activated by the ActivityListener
+    // registered in Program.cs (or an OpenTelemetry TracerProvider).
+    private static readonly ActivitySource s_activitySource = new("BlogWriter.ResearcherAgent");
+
+    private readonly ILogger<ResearcherAgent> _logger;
+
+    public ResearcherAgent(IChatClient llm, ChatOptions chatOptions, AIFunction tavilyTool, ILogger<ResearcherAgent> logger)
     {
+        _logger = logger;
+
         _agent = new ChatClientAgent(llm, new ChatClientAgentOptions
         {
             // Name surfaces in OpenTelemetry traces and agent logs.
@@ -35,11 +45,16 @@ public ResearcherAgent(IChatClient llm, ChatOptions chatOptions, AIFunction tavi
                 Tools = [tavilyTool],
             },
         });
+
+        _logger.LogInformation("ResearcherAgent initialized with Tavily tool: {ToolName}", tavilyTool.Name);
     }
 
     /// <summary>Execute research by letting the agent search and summarise.</summary>
     public async Task<string> InvokeAsync(string query)
     {
+        using Activity? activity = s_activitySource.StartActivity("Researcher.Invoke");
+        activity?.SetTag("blog.query", query);
+
         try
         {
             // A single agent run: the model may call tavily_search one or more

ReviewerAgent.cs

@@ -1,5 +1,7 @@
+using System.Diagnostics;
 using Microsoft.Agents.AI;
 using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
 
 namespace BlogWriter;
 
@@ -14,8 +16,16 @@ public class ReviewerAgent : IReviewerAgent
 {
     private readonly ChatClientAgent _agent;
 
-    public ReviewerAgent(IChatClient llm, ChatOptions chatOptions)
+    // Emits a span per review. Activated by the ActivityListener registered in
+    // Program.cs (or an OpenTelemetry TracerProvider).
+    private static readonly ActivitySource s_activitySource = new("BlogWriter.ReviewerAgent");
+
+    private readonly ILogger<ReviewerAgent> _logger;
+
+    public ReviewerAgent(IChatClient llm, ChatOptions chatOptions, ILogger<ReviewerAgent> logger)
     {
+        _logger = logger;
+
         _agent = new ChatClientAgent(llm, new ChatClientAgentOptions
         {
             Name = "Reviewer",
@@ -26,10 +36,14 @@ public ReviewerAgent(IChatClient llm, ChatOptions chatOptions)
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
         });
+        _logger.LogInformation("ReviewerAgent initialized.");   
     }
 
     public async Task<string> InvokeAsync(ResearchState state)
     {
+        using Activity? activity = s_activitySource.StartActivity("Reviewer.Invoke");
+        activity?.SetTag("blog.revision", state.RevisionNumber);
+
         string draft = state.Draft;
         int revisionNum = state.RevisionNumber;