added braintrust to agent. need to tweak a few more things

api/libs/agents/src/agent.rs

@@ -389,11 +389,15 @@ impl Agent {
             *current = Some(thread.clone());
         }
 
+        // Initialize Braintrust client
         let client = BraintrustClient::new(
             None,
             "c7b996a6-1c7c-482d-b23f-3d39de16f433"
         )?;
-
+        
+        // Create a root span for this thread
+        let root_span_id = thread.id.to_string();
+        
         if recursion_depth >= 30 {
             let message = AgentMessage::assistant(
                 Some("max_recursion_depth_message".to_string()),
@@ -427,10 +431,23 @@ impl Agent {
             ..Default::default()
         };
 
+        // Create a span for the LLM call
+        let llm_span = client.create_span(
+            "llm_call", 
+            "llm", 
+            Some(&root_span_id),
+            None
+        ).with_input(serde_json::to_value(&request)?);
+
         // Get the streaming response from the LLM
         let mut stream_rx = match self.llm_client.stream_chat_completion(request).await {
             Ok(rx) => rx,
-            Err(e) => return Err(anyhow::anyhow!("Error starting stream: {:?}", e)),
+            Err(e) => {
+                // Log error in span
+                let error_message = format!("Error starting stream: {:?}", e);
+                client.log_span(llm_span.with_output(serde_json::json!({"error": error_message}))).await?;
+                return Err(anyhow::anyhow!(error_message));
+            },
         };
 
         // Process the streaming chunks
@@ -483,7 +500,12 @@ impl Agent {
                         is_complete = true;
                     }
                 }
-                Err(e) => return Err(anyhow::anyhow!("Error in stream: {:?}", e)),
+                Err(e) => {
+                    // Log error in span
+                    let error_message = format!("Error in stream: {:?}", e);
+                    client.log_span(llm_span.with_output(serde_json::json!({"error": error_message}))).await?;
+                    return Err(anyhow::anyhow!(error_message));
+                },
             }
         }
 
@@ -508,6 +530,24 @@ impl Agent {
             Some(self.name.clone()),
         );
 
+        // Log the LLM response in Braintrust
+        let llm_output = if let Some(content) = &final_message.get_content() {
+            serde_json::json!({
+                "content": content,
+                "tool_calls": final_tool_calls
+            })
+        } else {
+            serde_json::json!({
+                "tool_calls": final_tool_calls
+            })
+        };
+
+        // Clone the span_id before moving llm_span
+        let llm_span_id = llm_span.clone().span_id().to_string();
+
+        // Now we can safely move llm_span
+        client.log_span(llm_span.with_output(llm_output)).await?;
+
         // Broadcast the final assistant message
         self.get_stream_sender()
             .await
@@ -532,8 +572,32 @@ impl Agent {
             // Execute each requested tool
             for tool_call in tool_calls {
                 if let Some(tool) = self.tools.read().await.get(&tool_call.function.name) {
+                    // Create a span for the tool call
+                    let tool_span = client.create_span(
+                        &tool_call.function.name, 
+                        "tool", 
+                        Some(&root_span_id),
+                        Some(&llm_span_id)
+                    );
+                    
+                    // Parse the parameters and log them
                     let params: Value = serde_json::from_str(&tool_call.function.arguments)?;
-                    let result = tool.execute(params, tool_call.id.clone()).await?;
+                    let tool_span = tool_span.with_input(params.clone());
+                    
+                    // Execute the tool
+                    let result = match tool.execute(params, tool_call.id.clone()).await {
+                        Ok(r) => r,
+                        Err(e) => {
+                            // Log error in tool span
+                            let error_message = format!("Tool execution error: {:?}", e);
+                            client.log_span(tool_span.with_output(serde_json::json!({"error": error_message}))).await?;
+                            return Err(anyhow::anyhow!(error_message));
+                        }
+                    };
+                    
+                    // Log the tool result
+                    client.log_span(tool_span.with_output(result.clone())).await?;
+                    
                     let result_str = serde_json::to_string(&result)?;
                     let tool_message = AgentMessage::tool(
                         None,