feat(observability): emit guardrail findings as span events on ETW DTO path

src/Observability/Runtime/Common/ExportFormatter.cs

@@ -152,7 +152,8 @@ public string FormatLogData(IDictionary<string, object?> data)
                 Kind = data.TryGetValue("SpanKind", out var spanKindObj) && spanKindObj != null ? spanKindObj : SpanKindConstants.Client,
                 Status = data.TryGetValue("Status", out var statusObj) && statusObj != null
                     ? statusObj
-                    : new Dictionary<string, object> { { "code", 0 }, { "message", "" } }
+                    : new Dictionary<string, object> { { "code", 0 }, { "message", "" } },
+                Events = data.TryGetValue("Events", out var eventsObj) ? eventsObj : null
             };
 
             return SerializePayload(payload);
@@ -367,7 +368,7 @@ internal sealed class EtwResourceSpan
     {
         [JsonPropertyName("resource")]
         public OtlpResource? Resource { get; set; }
-        
+
         [JsonPropertyName("scopeSpan")]
         public EtwScopeSpan ScopeSpan { get; set; } = new EtwScopeSpan();
     }
@@ -376,7 +377,7 @@ internal sealed class EtwScopeSpan
     {
         [JsonPropertyName("scope")]
         public InstrumentationScope? Scope { get; set; }
-     
+
         [JsonPropertyName("span")]
         public OtlpSpan Span { get; set; } = new OtlpSpan();
     }

src/Observability/Runtime/DTOs/BaseData.cs

@@ -92,6 +92,13 @@ public BaseData(
         /// </summary>
         public string? StatusMessage { get; set; }
 
+        /// <summary>
+        /// Gets the span events for the operation. Each event is a dictionary with OTLP-style keys
+        /// (<c>timeUnixNano</c>, <c>name</c>, <c>attributes</c>), matching the Activity export path.
+        /// Empty by default; populated by builders that emit events (e.g. apply_guardrail findings).
+        /// </summary>
+        public List<Dictionary<string, object?>> Events { get; } = new List<Dictionary<string, object?>>();
+
         /// <summary>
         /// Gets the duration of the operation if both start and end times are provided.
         /// </summary>
@@ -124,6 +131,11 @@ public BaseData(
                 }
             };
 
+            if (Events.Count > 0)
+            {
+                dict["Events"] = Events;
+            }
+
             return dict;
         }
     }

src/Observability/Runtime/DTOs/Builders/ApplyGuardrailDataBuilder.cs

@@ -30,6 +30,7 @@ public class ApplyGuardrailDataBuilder : BaseDataBuilder<ApplyGuardrailData>
         /// <param name="spanKind">Optional span kind override.</param>
         /// <param name="traceId">Optional trace ID for distributed tracing.</param>
         /// <param name="error">Optional exception describing a failure; sets an OTel error status and the <c>error.type</c> attribute.</param>
+        /// <param name="findings">Optional security findings to emit as span events on the apply_guardrail span.</param>
         /// <returns>An ApplyGuardrailData object containing all telemetry data.</returns>
         public static ApplyGuardrailData Build(
             GuardrailDetails guardrailDetails,
@@ -44,11 +45,55 @@ public static ApplyGuardrailData Build(
             IDictionary<string, object?>? extraAttributes = null,
             string? spanKind = null,
             string? traceId = null,
-            Exception? error = null)
+            Exception? error = null,
+            IEnumerable<GuardrailFinding>? findings = null)
         {
             var attributes = BuildAttributes(guardrailDetails, agentDetails, conversationId, channel, callerDetails, extraAttributes);
 
-            return ApplyStatus(new ApplyGuardrailData(parentSpanId, attributes, startTime, endTime, spanId, spanKind, traceId), error);
+            var data = ApplyStatus(new ApplyGuardrailData(parentSpanId, attributes, startTime, endTime, spanId, spanKind, traceId), error);
+
+            AddFindingEvents(data, findings);
+
+            return data;
+        }
+
+        private static void AddFindingEvents(ApplyGuardrailData data, IEnumerable<GuardrailFinding>? findings)
+        {
+            if (findings == null)
+            {
+                return;
+            }
+
+            foreach (var finding in findings)
+            {
+                if (finding == null)
+                {
+                    continue;
+                }
+
+                var eventAttributes = new Dictionary<string, object?>
+                {
+                    { OpenTelemetryConstants.GenAiSecurityRiskCategoryKey, finding.RiskCategory },
+                    { OpenTelemetryConstants.GenAiSecurityRiskSeverityKey, finding.RiskSeverity }
+                };
+
+                AddIfNotNull(eventAttributes, OpenTelemetryConstants.GenAiSecurityPolicyDecisionTypeKey, finding.PolicyDecisionType);
+                AddIfNotNull(eventAttributes, OpenTelemetryConstants.GenAiSecurityPolicyIdKey, finding.PolicyId);
+                AddIfNotNull(eventAttributes, OpenTelemetryConstants.GenAiSecurityPolicyNameKey, finding.PolicyName);
+                AddIfNotNull(eventAttributes, OpenTelemetryConstants.GenAiSecurityPolicyVersionKey, finding.PolicyVersion);
+                if (finding.RiskScore.HasValue)
+                {
+                    eventAttributes[OpenTelemetryConstants.GenAiSecurityRiskScoreKey] = finding.RiskScore.Value;
+                }
+                AddIfNotNull(eventAttributes, OpenTelemetryConstants.GenAiSecurityRiskMetadataKey, finding.RiskMetadata);
+
+                data.Events.Add(new Dictionary<string, object?>
+                {
+                    { "timeUnixNano", ToUnixNanos(DateTimeOffset.UtcNow) },
+                    { "name", OpenTelemetryConstants.GenAiSecurityFindingEventName },
+                    { "attributes", eventAttributes }
+                });
+            }
         }
 
         private static Dictionary<string, object?> BuildAttributes(

src/Observability/Runtime/DTOs/Builders/BaseDataBuilder.cs

@@ -168,6 +168,17 @@ protected static void AddIfNotNull(IDictionary<string, object?> attributes, stri
             }
         }
 
+        /// <summary>
+        /// Converts a timestamp to Unix epoch nanoseconds, matching the Activity export path's
+        /// conversion in <c>ExportFormatter</c>. Used to stamp span events on the ETW DTO path.
+        /// </summary>
+        protected static ulong ToUnixNanos(DateTimeOffset timestamp)
+        {
+            var unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            var ns = (timestamp.UtcDateTime - unixEpoch).Ticks * 100;
+            return (ulong)ns;
+        }
+
         /// <summary>
         /// Adds extra attributes to the attributes dictionary.
         /// Extra attributes cannot override keys already set by the builder on this span.

src/Observability/Runtime/Etw/A365EtwLogger.cs

@@ -37,14 +37,14 @@ public A365EtwLogger(ILoggerFactory factory)
 
         /// <inheritdoc/>
         public void LogInferenceCall(
-            InferenceCallDetails inferenceCallDetails, 
-            AgentDetails agentDetails, 
-            string conversationId, 
-            string[]? inputMessages, 
-            string[]? outputMessages, 
-            DateTimeOffset? startTime, 
-            DateTimeOffset? endTime, 
-            string? spanId, 
+            InferenceCallDetails inferenceCallDetails,
+            AgentDetails agentDetails,
+            string conversationId,
+            string[]? inputMessages,
+            string[]? outputMessages,
+            DateTimeOffset? startTime,
+            DateTimeOffset? endTime,
+            string? spanId,
             string? parentSpanId,
             Channel? channel,
             CallerDetails? callerDetails,
@@ -77,16 +77,16 @@ public void LogInferenceCall(
 
         /// <inheritdoc/>
         public void LogInvokeAgent(
-            InvokeAgentScopeDetails invokeAgentScopeDetails, 
-            AgentDetails agentDetails, 
-            string conversationId, 
-            Request? request, 
-            CallerDetails? callerDetails, 
-            string[]? inputMessages, 
-            string[]? outputMessages, 
-            DateTimeOffset? startTime, 
-            DateTimeOffset? endTime, 
-            string? spanId, 
+            InvokeAgentScopeDetails invokeAgentScopeDetails,
+            AgentDetails agentDetails,
+            string conversationId,
+            Request? request,
+            CallerDetails? callerDetails,
+            string[]? inputMessages,
+            string[]? outputMessages,
+            DateTimeOffset? startTime,
+            DateTimeOffset? endTime,
+            string? spanId,
             string? parentSpanId,
             string? traceId,
             Exception? error = null)
@@ -117,13 +117,13 @@ public void LogInvokeAgent(
 
         /// <inheritdoc/>
         public void LogToolCall(
-            ToolCallDetails toolCallDetails, 
-            AgentDetails agentDetails, 
-            string conversationId, 
-            string? responseContent, 
-            DateTimeOffset? startTime, 
-            DateTimeOffset? endTime, 
-            string? spanId, 
+            ToolCallDetails toolCallDetails,
+            AgentDetails agentDetails,
+            string conversationId,
+            string? responseContent,
+            DateTimeOffset? startTime,
+            DateTimeOffset? endTime,
+            string? spanId,
             string? parentSpanId,
             Channel? channel,
             CallerDetails? callerDetails,
@@ -201,7 +201,8 @@ public void LogApplyGuardrail(
             Channel? channel = null,
             CallerDetails? callerDetails = null,
             string? traceId = null,
-            Exception? error = null)
+            Exception? error = null,
+            IEnumerable<GuardrailFinding>? findings = null)
         {
             var data = ApplyGuardrailDataBuilder.Build(
                 guardrailDetails,
@@ -214,7 +215,8 @@ public void LogApplyGuardrail(
                 channel,
                 callerDetails: callerDetails,
                 traceId: traceId,
-                error: error);
+                error: error,
+                findings: findings);
 
             logger.Log(
                 LogLevel.Information,

src/Observability/Runtime/Etw/IA365EtwLogger.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.Agents.A365.Observability.Runtime.Tracing.Contracts;
 using System;
+using System.Collections.Generic;
 
 namespace Microsoft.Agents.A365.Observability.Runtime.Etw
 {
@@ -143,6 +144,7 @@ public void LogOutput(
         /// <param name="callerDetails">Optional details of the caller.</param>
         /// <param name="traceId">Optional trace ID for distributed tracing.</param>
         /// <param name="error">Optional exception describing a failure; sets an OTel error status and the <c>error.type</c> attribute.</param>
+        /// <param name="findings">Optional security findings to emit as span events on the apply_guardrail span.</param>
         public void LogApplyGuardrail(
             GuardrailDetails guardrailDetails,
             AgentDetails agentDetails,
@@ -154,6 +156,7 @@ public void LogApplyGuardrail(
             Channel? channel = null,
             CallerDetails? callerDetails = null,
             string? traceId = null,
-            Exception? error = null);
+            Exception? error = null,
+            IEnumerable<GuardrailFinding>? findings = null);
     }
 }

src/Tests/Microsoft.Agents.A365.Observability.Runtime.Tests/Common/ExportFormatterEventsTests.cs

@@ -0,0 +1,112 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Linq;
+using System.Text.Json;
+using FluentAssertions;
+using Microsoft.Agents.A365.Observability.Runtime.DTOs;
+using Microsoft.Agents.A365.Observability.Runtime.DTOs.Builders;
+using Microsoft.Agents.A365.Observability.Runtime.Tracing.Contracts;
+using Microsoft.Agents.A365.Observability.Runtime.Tracing.Scopes;
+
+namespace Microsoft.Agents.A365.Observability.Runtime.Tests.Common;
+
+public partial class ExportFormatterTests
+{
+    [TestMethod]
+    public void FormatLogData_NoEvents_OmitsEventsField()
+    {
+        // Arrange
+        var data = new InvokeAgentData(
+            new Dictionary<string, object?> { { "key", "val" } },
+            spanId: "span-1");
+        var formatter = CreateFormatter();
+
+        // Act
+        var json = formatter.FormatLogData(data.ToDictionary());
+
+        // Assert
+        using var doc = JsonDocument.Parse(json);
+        doc.RootElement.TryGetProperty("Events", out _).Should().BeFalse();
+    }
+
+    [TestMethod]
+    public void FormatLogData_WithFindings_EmitsEventsArray()
+    {
+        // Arrange
+        var details = new GuardrailDetails(
+            targetType: GuardrailTargetType.LlmInput,
+            decisionType: GuardrailDecisionType.Deny);
+        var findings = new[]
+        {
+            new GuardrailFinding("prompt_injection", GuardrailRiskSeverity.High, policyDecisionType: "deny")
+        };
+        var data = ApplyGuardrailDataBuilder.Build(details, TestAgentDetails, "conv-1", "parent-1", findings: findings);
+        var formatter = CreateFormatter();
+
+        // Act
+        var json = formatter.FormatLogData(data.ToDictionary());
+
+        // Assert
+        using var doc = JsonDocument.Parse(json);
+        var events = doc.RootElement.GetProperty("Events");
+        events.GetArrayLength().Should().Be(1);
+        var evt = events[0];
+        evt.GetProperty("name").GetString().Should().Be(OpenTelemetryConstants.GenAiSecurityFindingEventName);
+        evt.GetProperty("timeUnixNano").GetUInt64().Should().BeGreaterThan(0);
+        var attrs = evt.GetProperty("attributes");
+        attrs.GetProperty(OpenTelemetryConstants.GenAiSecurityRiskCategoryKey).GetString().Should().Be("prompt_injection");
+        attrs.GetProperty(OpenTelemetryConstants.GenAiSecurityRiskSeverityKey).GetString().Should().Be("high");
+        attrs.GetProperty(OpenTelemetryConstants.GenAiSecurityPolicyDecisionTypeKey).GetString().Should().Be("deny");
+    }
+
+    [TestMethod]
+    public void FindingEvent_DtoPath_StructurallyMatches_ActivityPath()
+    {
+        // Arrange — one finding with all fields populated.
+        var finding = new GuardrailFinding(
+            riskCategory: "sensitive_info_disclosure",
+            riskSeverity: GuardrailRiskSeverity.High,
+            policyDecisionType: "deny",
+            policyId: "policy_pii_v2",
+            policyName: "PII Policy",
+            policyVersion: "2.0",
+            riskScore: 0.92,
+            riskMetadata: new[] { "pattern:ssn", "count:2" });
+
+        var details = new GuardrailDetails(
+            targetType: GuardrailTargetType.LlmInput,
+            decisionType: GuardrailDecisionType.Deny);
+
+        var resource = CreateResource();
+        var formatter = CreateFormatter();
+
+        // Activity path: RecordFinding -> FormatSingle
+        var activity = ListenForActivity(() =>
+        {
+            using var scope = ApplyGuardrailScope.Start(details, TestAgentDetails);
+            scope.RecordFinding(finding);
+        });
+        using var activityDoc = JsonDocument.Parse(formatter.FormatSingle(activity, resource));
+        var activityEvent = activityDoc.RootElement
+            .GetProperty("resourceSpan")
+            .GetProperty("scopeSpan")
+            .GetProperty("span")
+            .GetProperty("events")[0];
+
+        // DTO path: ApplyGuardrailDataBuilder -> FormatLogData
+        var data = ApplyGuardrailDataBuilder.Build(details, TestAgentDetails, "conv-1", "parent-1", findings: new[] { finding });
+        using var dtoDoc = JsonDocument.Parse(formatter.FormatLogData(data.ToDictionary()));
+        var dtoEvent = dtoDoc.RootElement.GetProperty("Events")[0];
+
+        // Assert — same event name and same attributes (timeUnixNano intentionally ignored).
+        dtoEvent.GetProperty("name").GetString()
+            .Should().Be(activityEvent.GetProperty("name").GetString());
+
+        AttributeMap(dtoEvent.GetProperty("attributes"))
+            .Should().BeEquivalentTo(AttributeMap(activityEvent.GetProperty("attributes")));
+    }
+
+    private static Dictionary<string, string> AttributeMap(JsonElement attributes) =>
+        attributes.EnumerateObject().ToDictionary(p => p.Name, p => p.Value.GetRawText());
+}