Added UseOpenTelemetry

AuthorAgent.cs

@@ -13,7 +13,7 @@ namespace BlogWriter;
 /// </summary>
 public class AuthorAgent : IAuthorAgent
 {
-    private readonly ChatClientAgent _agent;
+    private readonly AIAgent _agent;
 
     // Emits a span per draft creation/revision. Activated by the ActivityListener
     // registered in Program.cs (or an OpenTelemetry TracerProvider).
@@ -38,7 +38,10 @@ public AuthorAgent(IChatClient llm, ChatOptions chatOptions, ILogger<AuthorAgent
                 Temperature = chatOptions.Temperature,
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
-        });
+        })
+        .AsBuilder()
+        .UseOpenTelemetry(sourceName: "BlogWriter.Agents")
+        .Build();
         _logger.LogInformation("AuthorAgent initialized.");
     }
 

BloggerAgent.cs

@@ -17,7 +17,7 @@ public class BloggerAgent : IBloggerAgent
 {
     // Built once and reused. Holds the static Blogger instructions; the volatile
     // state is passed per-turn as the user message.
-    private readonly ChatClientAgent _agent;
+    private readonly AIAgent _agent;
 
     // Web-style options are sufficient: BloggerDecision carries explicit
     // [JsonPropertyName] attributes (next_step / task_description) that drive the
@@ -47,7 +47,10 @@ public BloggerAgent(IChatClient llm, ChatOptions chatOptions, ILogger<BloggerAge
                 Temperature = chatOptions.Temperature,
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
-        });
+        })
+        .AsBuilder()
+        .UseOpenTelemetry(sourceName: "BlogWriter.Agents")
+        .Build();
         _logger.LogInformation("BloggerAgent initialized.");
     }
 

Program.cs

@@ -35,8 +35,13 @@
 // calls the model requests — without it, attaching the Tavily tool to the
 // Researcher agent would let the model ask for a search but nothing would run it.
 // Middleware is applied inner-to-outer, so function invocation wraps the raw
-// OpenAI client. (To add distributed tracing later, chain .UseOpenTelemetry()
-// here and register the source with a TracerProvider.)
+// OpenAI client.
+//
+// UseOpenTelemetry() emits a GenAI span per model round-trip (model name, token
+// usage, tool calls). Its source is named "BlogWriter.ChatClient" so the
+// ActivityListener registered below (which listens to every "BlogWriter.*"
+// source) captures it alongside the agent/workflow spans — no TracerProvider
+// or extra packages required.
 //
 // TokenCapChatClient is registered *after* function invocation, which makes it
 // the innermost wrapper around the raw client — so it observes every individual
@@ -47,6 +52,7 @@
     .AsIChatClient()
     .AsBuilder()
     .UseFunctionInvocation()
+    .UseOpenTelemetry(sourceName: "BlogWriter.ChatClient")
     .Use(inner => new TokenCapChatClient(inner, maxTotalTokens: 10000))
     .Build();
 
@@ -90,9 +96,10 @@
 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.
+// ActivitySource in the app (agents, workflow, and the IChatClient's
+// "BlogWriter.ChatClient" GenAI spans) and writes span start/stop to the
+// console. Swap this listener for OpenTelemetry's TracerProvider to export the
+// same spans to a backend instead.
 var appActivitySource = new ActivitySource("BlogWriter.Program");
 
 ActivitySource.AddActivityListener(new ActivityListener

ResearcherAgent.cs

@@ -17,7 +17,7 @@ public class ResearcherAgent : IResearcherAgent
     // The agent is built once and reused for every research turn. It is stateless
     // across turns (no AgentSession is retained), which matches the original
     // per-call behaviour while gaining tool-calling for free.
-    private readonly ChatClientAgent _agent;
+    private readonly AIAgent _agent;
 
     // Emits a span per research turn. Activated by the ActivityListener
     // registered in Program.cs (or an OpenTelemetry TracerProvider).
@@ -48,7 +48,10 @@ public ResearcherAgent(IChatClient llm, ChatOptions chatOptions, AIFunction tavi
                 // Attaching the tool lets the model call it autonomously.
                 Tools = [tavilyTool],
             },
-        });
+        })
+        .AsBuilder()
+        .UseOpenTelemetry(sourceName: "BlogWriter.Agents")
+        .Build();
 
         _logger.LogInformation("ResearcherAgent initialized with Tavily tool: {ToolName}", tavilyTool.Name);
     }

ReviewerAgent.cs

@@ -14,7 +14,7 @@ namespace BlogWriter;
 /// </summary>
 public class ReviewerAgent : IReviewerAgent
 {
-    private readonly ChatClientAgent _agent;
+    private readonly AIAgent _agent;
 
     // Emits a span per review. Activated by the ActivityListener registered in
     // Program.cs (or an OpenTelemetry TracerProvider).
@@ -39,7 +39,10 @@ public ReviewerAgent(IChatClient llm, ChatOptions chatOptions, ILogger<ReviewerA
                 Temperature = chatOptions.Temperature,
                 MaxOutputTokens = chatOptions.MaxOutputTokens,
             },
-        });
+        })
+        .AsBuilder()
+        .UseOpenTelemetry(sourceName: "BlogWriter.Agents")
+        .Build();
         _logger.LogInformation("ReviewerAgent initialized.");
     }