diff --git a/packages/agents-a365-observability-hosting/src/utils/TurnContextUtils.ts b/packages/agents-a365-observability-hosting/src/utils/TurnContextUtils.ts
index acc7285b..7781095b 100644
--- a/packages/agents-a365-observability-hosting/src/utils/TurnContextUtils.ts
+++ b/packages/agents-a365-observability-hosting/src/utils/TurnContextUtils.ts
@@ -27,10 +27,10 @@ export function getCallerBaggagePairs(turnContext: TurnContext): Array<[string,
     return [];
   }
   const from = turnContext.activity.from;
-    
+
   const upn = from.agenticUserId;
   const pairs: Array<[string, string | undefined]> = [
-    [OpenTelemetryConstants.USER_ID_KEY, from.aadObjectId],
+    [OpenTelemetryConstants.USER_ID_KEY, from.aadObjectId || from.agenticUserId || from.id],
     [OpenTelemetryConstants.USER_NAME_KEY, from.name],
     [OpenTelemetryConstants.USER_EMAIL_KEY, upn],
     [OpenTelemetryConstants.GEN_AI_CALLER_AGENT_APPLICATION_ID_KEY, from.agenticAppBlueprintId]
diff --git a/tests/jest.config.cjs b/tests/jest.config.cjs
index 3627b5ff..be68efed 100644
--- a/tests/jest.config.cjs
+++ b/tests/jest.config.cjs
@@ -71,6 +71,7 @@ module.exports = {
     '^@microsoft/agents-a365-observability$': '<rootDir>/packages/agents-a365-observability/src',
     '^@microsoft/agents-a365-observability-extensions-langchain$': '<rootDir>/packages/agents-a365-observability-extensions-langchain/src',
     '^@microsoft/agents-a365-observability-extensions-openai$': '<rootDir>/packages/agents-a365-observability-extensions-openai/src',
+    '^@microsoft/agents-a365-observability-hosting$': '<rootDir>/packages/agents-a365-observability-hosting/src',
     '^@microsoft/agents-a365-observability-tokencache$': '<rootDir>/packages/agents-a365-observability-tokencache/src',
     '^@microsoft/agents-a365-tooling$': '<rootDir>/packages/agents-a365-tooling/src',
     '^@microsoft/agents-a365-tooling-extensions-claude$': '<rootDir>/packages/agents-a365-tooling-extensions-claude/src',
diff --git a/tests/observability/extension/hosting/BaggageBuilderUtils.test.ts b/tests/observability/extension/hosting/BaggageBuilderUtils.test.ts
index 023d2d03..23983744 100644
--- a/tests/observability/extension/hosting/BaggageBuilderUtils.test.ts
+++ b/tests/observability/extension/hosting/BaggageBuilderUtils.test.ts
@@ -45,7 +45,7 @@ describe('BaggageBuilderUtils', () => {
     expect(result).toBe(builder);
     // Validate every expected OpenTelemetry baggage key and value
     const asObj = Object.fromEntries(capturedPairs);
-    expect(asObj[OpenTelemetryConstants.USER_ID_KEY]).toBeUndefined();
+    expect(asObj[OpenTelemetryConstants.USER_ID_KEY]).toBe('agentic-user-1');
     expect(asObj[OpenTelemetryConstants.USER_NAME_KEY]).toBe('User One');
     expect(asObj[OpenTelemetryConstants.USER_EMAIL_KEY]).toBe('agentic-user-1');
     expect(asObj[OpenTelemetryConstants.GEN_AI_AGENT_ID_KEY]).toBe('agent-app-1');
diff --git a/tests/observability/extension/hosting/TurnContextUtils.test.ts b/tests/observability/extension/hosting/TurnContextUtils.test.ts
index 675c01ce..8d811c0a 100644
--- a/tests/observability/extension/hosting/TurnContextUtils.test.ts
+++ b/tests/observability/extension/hosting/TurnContextUtils.test.ts
@@ -32,6 +32,58 @@ describe('TurnContextUtils', () => {
     expect(pairs.length).toBeGreaterThan(0);
   });
 
+  it('should fall back to from.id for userId when aadObjectId is undefined (non-Teams channel)', () => {
+    const ctx = {
+      activity: {
+        from: { id: 'user1', name: 'User One' },
+        recipient: { id: 'agent1', name: 'Agent One' },
+        conversation: { id: 'conv-1' },
+      },
+    } as any;
+    const pairs = getCallerBaggagePairs(ctx);
+    const obj = Object.fromEntries(pairs);
+    expect(obj[OpenTelemetryConstants.USER_ID_KEY]).toBe('user1');
+  });
+
+  it('should fall back to agenticUserId for userId when aadObjectId is undefined (A2A)', () => {
+    const ctx = {
+      activity: {
+        from: { id: 'user1', name: 'User One', agenticUserId: 'agentic-user-1' },
+        recipient: { id: 'agent1', name: 'Agent One' },
+        conversation: { id: 'conv-1' },
+      },
+    } as any;
+    const pairs = getCallerBaggagePairs(ctx);
+    const obj = Object.fromEntries(pairs);
+    expect(obj[OpenTelemetryConstants.USER_ID_KEY]).toBe('agentic-user-1');
+  });
+
+  it('should prefer aadObjectId for userId when all three fields are set', () => {
+    const ctx = {
+      activity: {
+        from: { id: 'user1', name: 'User One', aadObjectId: 'aad-123', agenticUserId: 'agentic-user-1' },
+        recipient: { id: 'agent1', name: 'Agent One' },
+        conversation: { id: 'conv-1' },
+      },
+    } as any;
+    const pairs = getCallerBaggagePairs(ctx);
+    const obj = Object.fromEntries(pairs);
+    expect(obj[OpenTelemetryConstants.USER_ID_KEY]).toBe('aad-123');
+  });
+
+  it('should resolve userId to agenticUserId when it is a GUID (A2A with GUID agenticUserId)', () => {
+    const ctx = {
+      activity: {
+        from: { id: 'user1', name: 'User One', agenticUserId: 'bef730f4-d6f5-4ffb-b759-26ffa449ed7e' },
+        recipient: { id: 'agent1', name: 'Agent One' },
+        conversation: { id: 'conv-1' },
+      },
+    } as any;
+    const pairs = getCallerBaggagePairs(ctx);
+    const obj = Object.fromEntries(pairs);
+    expect(obj[OpenTelemetryConstants.USER_ID_KEY]).toBe('bef730f4-d6f5-4ffb-b759-26ffa449ed7e');
+  });
+
   it('should get target agent baggage pairs', () => {
     const pairs = getTargetAgentBaggagePairs(mockTurnContext);
     expect(Array.isArray(pairs)).toBe(true);