Add support for LangSmith OpenTelemetry genai standard attributes (dotnet#12861)

Co-authored-by: JamesNK <303201+JamesNK@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: James Newton-King <james@newtonking.com>

Author: Copilot

playground/Stress/Stress.ApiService/Program.cs

@@ -537,6 +537,45 @@ async IAsyncEnumerable<string> WriteOutput()
     return "Created GenAI trace";
 });
 
+app.MapGet("/genai-langchain-trace", async () =>
+{
+    var source = new ActivitySource("Services.Api", "1.0.0");
+
+    var activity = source.StartActivity("langchain llm call", ActivityKind.Client);
+    if (activity != null)
+    {
+        activity.SetTag("gen_ai.system", "langchain");
+        activity.SetTag("gen_ai.provider.name", "openai");
+        activity.SetTag("gen_ai.response.model", "gpt-4");
+        activity.SetTag("gen_ai.usage.input_tokens", 150);
+        activity.SetTag("gen_ai.usage.output_tokens", 75);
+
+        // LangSmith/LangChain format uses flattened indexed attributes
+        // Prompt messages
+        activity.SetTag("gen_ai.prompt.0.role", "system");
+        activity.SetTag("gen_ai.prompt.0.content", "You are a helpful AI assistant that provides accurate and concise information.");
+
+        activity.SetTag("gen_ai.prompt.1.role", "user");
+        activity.SetTag("gen_ai.prompt.1.content", "What is the capital of France?");
+
+        activity.SetTag("gen_ai.prompt.2.role", "assistant");
+        activity.SetTag("gen_ai.prompt.2.content", "The capital of France is Paris. It is located in the north-central part of the country and is known for its art, culture, and history.");
+
+        activity.SetTag("gen_ai.prompt.3.message.role", "user");
+        activity.SetTag("gen_ai.prompt.3.message.content", "What about Germany?");
+
+        activity.SetTag("gen_ai.completion.1.message.role", "assistant");
+        activity.SetTag("gen_ai.completion.1.message.content", "The capital of Germany is Berlin. It is located in the northeastern part of the country and serves as the political and cultural center.");
+    }
+
+    // Avoid zero seconds span.
+    await Task.Delay(100);
+
+    activity?.Stop();
+
+    return "Created LangChain GenAI trace";
+});
+
 async Task SimulateWorkAsync(ActivitySource source, int index, int millisecondsDelay = 2)
 {
     using var activity = source.StartActivity($"WorkIteration{index + 1}");

playground/Stress/Stress.AppHost/Program.cs

@@ -88,6 +88,7 @@
 serviceBuilder.WithHttpCommand("/nested-trace-spans", "Out of order nested spans", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
 serviceBuilder.WithHttpCommand("/exemplars-no-span", "Examplars with no span", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
 serviceBuilder.WithHttpCommand("/genai-trace", "Gen AI trace", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
+serviceBuilder.WithHttpCommand("/genai-langchain-trace", "Gen AI LangChain trace", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
 serviceBuilder.WithHttpCommand("/genai-trace-display-error", "Gen AI trace display error", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
 serviceBuilder.WithHttpCommand("/log-formatting", "Log formatting", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });
 serviceBuilder.WithHttpCommand("/big-nested-trace", "Big nested trace", commandOptions: new() { Method = HttpMethod.Get, IconName = "ContentViewGalleryLightning" });

src/Aspire.Dashboard/Model/GenAI/GenAIHelpers.cs

@@ -17,6 +17,10 @@ public static class GenAIHelpers
     public const string GenAIUsageInputTokens = "gen_ai.usage.input_tokens";
     public const string GenAIUsageOutputTokens = "gen_ai.usage.output_tokens";
 
+    // LangSmith OpenTelemetry genai standard attributes (flattened format)
+    public const string GenAIPromptPrefix = "gen_ai.prompt.";
+    public const string GenAICompletionPrefix = "gen_ai.completion.";
+
     public static bool IsGenAISpan(KeyValuePair<string, string>[] attributes)
     {
         return attributes.GetValueWithFallback(GenAISystem, GenAIProviderName) is { Length: > 0 };

src/Aspire.Dashboard/Model/GenAI/GenAIVisualizerDialogViewModel.cs

@@ -232,6 +232,15 @@ private static void CreateMessages(GenAIVisualizerDialogViewModel viewModel, Tel
                 currentIndex++;
             }
         }
+
+        if (viewModel.Items.Count > 0)
+        {
+            return;
+        }
+
+        // Final fallback: attempt to parse LangSmith OpenTelemetry genai standard attributes.
+        // LangSmith uses a flattened format with indexed attributes like gen_ai.prompt.0.role, gen_ai.prompt.0.content, etc.
+        ParseLangSmithFormat(viewModel, ref currentIndex);
     }
 
     private static int ParseMessages(GenAIVisualizerDialogViewModel viewModel, string messages, string description, bool isOutput, ref int currentIndex)
@@ -254,6 +263,108 @@ private static int ParseMessages(GenAIVisualizerDialogViewModel viewModel, strin
         return currentIndex;
     }
 
+    // Parse LangSmith OpenTelemetry genai standard attributes format.
+    // LangSmith uses a flattened format with indexed attributes:
+    // gen_ai.prompt.0.role, gen_ai.prompt.0.content, gen_ai.prompt.1.role, etc.
+    // gen_ai.completion.0.role, gen_ai.completion.0.content, etc.
+    private static void ParseLangSmithFormat(GenAIVisualizerDialogViewModel viewModel, ref int currentIndex)
+    {
+        var attributes = viewModel.Span.Attributes;
+        
+        // Group attributes by prefix (prompt or completion) and index
+        var promptMessages = ExtractIndexedMessages(attributes, GenAIHelpers.GenAIPromptPrefix);
+        var completionMessages = ExtractIndexedMessages(attributes, GenAIHelpers.GenAICompletionPrefix);
+
+        // Parse prompt messages (inputs)
+        foreach (var (index, message) in promptMessages.OrderBy(kvp => kvp.Key))
+        {
+            var role = GetMessageRole(message, defaultRole: "user");
+            var content = GetMessageContent(message);
+
+            if (content != null)
+            {
+                var parts = new List<GenAIItemPartViewModel>
+                {
+                    GenAIItemPartViewModel.CreateMessagePart(new TextPart { Content = content })
+                };
+
+                var type = role switch
+                {
+                    "system" => GenAIItemType.SystemMessage,
+                    "user" => GenAIItemType.UserMessage,
+                    "assistant" => GenAIItemType.AssistantMessage,
+                    "tool" => GenAIItemType.ToolMessage,
+                    _ => GenAIItemType.UserMessage
+                };
+
+                viewModel.Items.Add(CreateMessage(viewModel, currentIndex, type, parts, internalId: null));
+                currentIndex++;
+            }
+        }
+
+        // Parse completion messages (outputs)
+        foreach (var (index, message) in completionMessages.OrderBy(kvp => kvp.Key))
+        {
+            var role = GetMessageRole(message, defaultRole: "assistant");
+            var content = GetMessageContent(message);
+
+            if (content != null)
+            {
+                var parts = new List<GenAIItemPartViewModel>
+                {
+                    GenAIItemPartViewModel.CreateMessagePart(new TextPart { Content = content })
+                };
+
+                viewModel.Items.Add(CreateMessage(viewModel, currentIndex, GenAIItemType.OutputMessage, parts, internalId: null));
+                currentIndex++;
+            }
+        }
+
+        // Extract role from message dictionary with fallback to message.role and default
+        static string GetMessageRole(Dictionary<string, string> message, string defaultRole)
+        {
+            return message.TryGetValue("role", out var r) ? r : message.GetValueOrDefault("message.role", defaultRole);
+        }
+
+        // Extract content from message dictionary with fallback to message.content
+        static string? GetMessageContent(Dictionary<string, string> message)
+        {
+            return message.TryGetValue("content", out var c) ? c : message.GetValueOrDefault("message.content");
+        }
+    }
+
+    // Extract messages from indexed span attributes like gen_ai.prompt.0.role, gen_ai.prompt.0.content
+    private static Dictionary<int, Dictionary<string, string>> ExtractIndexedMessages(KeyValuePair<string, string>[] attributes, string prefix)
+    {
+        var messages = new Dictionary<int, Dictionary<string, string>>();
+
+        foreach (var attr in attributes)
+        {
+            if (attr.Key.StartsWith(prefix, StringComparison.Ordinal))
+            {
+                // Extract index and field name from attribute key
+                // Format: gen_ai.prompt.{index}.{field}
+                var remainder = attr.Key.AsSpan(prefix.Length);
+                var dotIndex = remainder.IndexOf('.');
+                
+                if (dotIndex > 0 && int.TryParse(remainder.Slice(0, dotIndex), out var messageIndex))
+                {
+                    var fieldName = remainder.Slice(dotIndex + 1).ToString();
+                    
+                    if (!messages.TryGetValue(messageIndex, out var message))
+                    {
+                        message = new Dictionary<string, string>();
+                        messages[messageIndex] = message;
+                    }
+
+                    message[fieldName] = attr.Value;
+                }
+            }
+        }
+
+        return messages;
+    }
+
     private static GenAIItemViewModel CreateMessage(GenAIVisualizerDialogViewModel viewModel, int currentIndex, GenAIItemType type, List<GenAIItemPartViewModel> parts, long? internalId)
     {
         return new GenAIItemViewModel