diff --git a/packages/agents-a365-observability/src/ObservabilityBuilder.ts b/packages/agents-a365-observability/src/ObservabilityBuilder.ts
index d55f2fcf..d09484d2 100644
--- a/packages/agents-a365-observability/src/ObservabilityBuilder.ts
+++ b/packages/agents-a365-observability/src/ObservabilityBuilder.ts
@@ -9,7 +9,7 @@ import { Agent365Exporter } from './tracing/exporter/Agent365Exporter';
 import type { TokenResolver } from './tracing/exporter/Agent365ExporterOptions';
 import { Agent365ExporterOptions } from './tracing/exporter/Agent365ExporterOptions';
 import { PerRequestSpanProcessor } from './tracing/PerRequestSpanProcessor';
-import { resourceFromAttributes } from '@opentelemetry/resources';
+import { resourceFromAttributes, envDetector, processDetector } from '@opentelemetry/resources';
 import { ATTR_SERVICE_NAME, ATTR_SERVICE_NAMESPACE } from '@opentelemetry/semantic-conventions';
 import { trace } from '@opentelemetry/api';
 import { ClusterCategory, IConfigurationProvider } from '@microsoft/agents-a365-runtime';
@@ -261,6 +261,7 @@ export class ObservabilityBuilder {
     // Create & configure the NodeSDK manually so we can inject processors + resource.
     this.sdk = new NodeSDK({
       resource: this.createResource(),
+      resourceDetectors: [envDetector, processDetector],
       spanProcessors: [
         spanProcessor,
         exportProcessor,
diff --git a/tests/observability/core/observabilityBuilder-options.test.ts b/tests/observability/core/observabilityBuilder-options.test.ts
index ebfd2654..a4f4c98d 100644
--- a/tests/observability/core/observabilityBuilder-options.test.ts
+++ b/tests/observability/core/observabilityBuilder-options.test.ts
@@ -78,6 +78,7 @@ describe('ObservabilityBuilder exporterOptions merging', () => {
   });
 });
 
+
 describe('ObservabilityBuilder serviceNamespace', () => {
   let createResourceSpy: jest.SpyInstance;
 
diff --git a/tests/observability/core/observabilityManager.test.ts b/tests/observability/core/observabilityManager.test.ts
index 5eb0d850..f5d1bb81 100644
--- a/tests/observability/core/observabilityManager.test.ts
+++ b/tests/observability/core/observabilityManager.test.ts
@@ -1,5 +1,7 @@
 import { describe, it, expect, afterEach } from '@jest/globals';
 import { ObservabilityManager, Builder } from '@microsoft/agents-a365-observability';
+import { trace } from '@opentelemetry/api';
+import { ObservabilityBuilder } from '@microsoft/agents-a365-observability/src/ObservabilityBuilder';
 
 describe('Agent 365 SDK', () => {
   afterEach(async () => {
@@ -54,4 +56,88 @@ describe('Agent 365 SDK', () => {
     });
 
   });
+
+  describe('Resource detectors', () => {
+    it('should not include host.name or host.arch in exported spans', async () => {
+      // Force ObservabilityBuilder to take the NodeSDK code path
+      const getTracerProviderSpy = jest
+        .spyOn(trace, 'getTracerProvider')
+        .mockReturnValue({} as any);
+
+      const builder = new ObservabilityBuilder()
+        .withService('resource-detector-test', '1.0.0');
+
+      try {
+        builder.build();
+        builder.start();
+
+        // Restore only this spy so we can read the real provider set by NodeSDK
+        getTracerProviderSpy.mockRestore();
+
+        // Give async resource detectors time to resolve
+        await new Promise(resolve => setTimeout(resolve, 1000));
+
+        // The NodeSDK sets a ProxyTracerProvider as global.
+        const globalProvider = trace.getTracerProvider() as any;
+
+        // Walk the internal chain to find the resource
+        let resource: any;
+        const candidates = [
+          globalProvider?.resource,
+          globalProvider?.getDelegate?.()?.resource,
+          globalProvider?._delegate?.resource,
+          globalProvider?._delegate?.getDelegate?.()?.resource,
+        ];
+
+        for (const candidate of candidates) {
+          if (candidate?.attributes) {
+            resource = candidate;
+            break;
+          }
+        }
+
+        // Fallback: access from the builder's internal sdk field
+        if (!resource) {
+          const sdk = (builder as any).sdk;
+          if (sdk) {
+            const internalCandidates = [
+              sdk?._tracerProvider?.resource,
+              sdk?._resource,
+              sdk?.resource,
+            ];
+            for (const candidate of internalCandidates) {
+              if (candidate?.attributes) {
+                resource = candidate;
+                break;
+              }
+            }
+          }
+        }
+
+        expect(resource).toBeDefined();
+        expect(resource.attributes).toBeDefined();
+
+        // host.name and host.arch should NOT be present (hostDetector excluded)
+        expect(resource.attributes['host.name']).toBeUndefined();
+        expect(resource.attributes['host.arch']).toBeUndefined();
+
+        // service.instance.id should NOT be present (serviceInstanceIdDetector excluded)
+        expect(resource.attributes['service.instance.id']).toBeUndefined();
+
+        // process.pid SHOULD be present (processDetector kept)
+        expect(resource.attributes['process.pid']).toBeDefined();
+        expect(resource.attributes['process.pid']).toBe(process.pid);
+
+        // service.name SHOULD be present (explicitly set)
+        expect(resource.attributes['service.name']).toContain('resource-detector-test');
+      } finally {
+        if (getTracerProviderSpy.mockRestore) {
+          getTracerProviderSpy.mockRestore();
+        }
+
+        // Clean up
+        await builder.shutdown();
+      }
+    });
+  });
 });