diff --git a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.test.ts b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.test.ts
index a5bed404d9..c5a00bc11d 100644
--- a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.test.ts
+++ b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.test.ts
@@ -43,6 +43,7 @@ import { InstallationManager } from '../../utils/installationManager.js';
 
 import si from 'systeminformation';
 import type { Systeminformation } from 'systeminformation';
+import * as os from 'node:os';
 
 interface CustomMatchers<R = unknown> {
   toHaveMetadataValue: ([key, value]: [EventMetadataKey, string]) => R;
@@ -120,6 +121,7 @@ vi.mock('node:os', async (importOriginal) => {
   return {
     ...actual,
     cpus: vi.fn(() => [{ model: 'Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz' }]),
+    availableParallelism: vi.fn(() => 8),
     totalmem: vi.fn(() => 32 * 1024 * 1024 * 1024),
   };
 });
@@ -438,6 +440,26 @@ describe('ClearcutLogger', () => {
       });
     });
 
+    it('handles empty os.cpus() gracefully', async () => {
+      const { logger, loggerConfig } = setup({});
+      vi.mocked(os.cpus).mockReturnValueOnce([]);
+
+      await logger?.logStartSessionEvent(new StartSessionEvent(loggerConfig));
+
+      const event = logger?.createLogEvent(EventNames.API_ERROR, []);
+      const metadata = event?.event_metadata[0];
+
+      const cpuInfoEntry = metadata?.find(
+        (m) => m.gemini_cli_key === EventMetadataKey.GEMINI_CLI_CPU_INFO,
+      );
+      expect(cpuInfoEntry).toBeUndefined();
+
+      const cpuCoresEntry = metadata?.find(
+        (m) => m.gemini_cli_key === EventMetadataKey.GEMINI_CLI_CPU_CORES,
+      );
+      expect(cpuCoresEntry?.value).toBe('8');
+    });
+
     type SurfaceDetectionTestCase = {
       name: string;
       env: Record<string, string | undefined>;
diff --git a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
index a6a8b6d228..d0407aa0d6 100644
--- a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
+++ b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
@@ -615,14 +615,17 @@ export class ClearcutLogger {
 
     // Add hardware information only to the start session event
     const cpus = os.cpus();
-    data.push(
-      {
+    if (cpus && cpus.length > 0) {
+      data.push({
         gemini_cli_key: EventMetadataKey.GEMINI_CLI_CPU_INFO,
         value: cpus[0].model,
-      },
+      });
+    }
+
+    data.push(
       {
         gemini_cli_key: EventMetadataKey.GEMINI_CLI_CPU_CORES,
-        value: cpus.length.toString(),
+        value: os.availableParallelism().toString(),
       },
       {
         gemini_cli_key: EventMetadataKey.GEMINI_CLI_RAM_TOTAL_GB,