From abb49c65dd0dc5759ece36cf8df1d9d2d8adce5f Mon Sep 17 00:00:00 2001
From: Shivanee Persaud <shivaneep@google.com>
Date: Fri, 21 Aug 2026 13:43:15 -0700
Subject: [PATCH 1/5] feat(gax): support telemetry options in CallSettings for
 tracing

---
 core/packages/gax/src/clientInterface.ts   | 24 +++++-
 core/packages/gax/src/createApiCall.ts     | 24 +++++-
 core/packages/gax/src/gax.ts               | 17 +++++
 core/packages/gax/src/index.ts             |  2 +-
 core/packages/gax/test/unit/apiCallable.ts | 85 ++++++++++++++++++++--
 core/packages/gax/test/unit/gax.ts         | 71 ++++++++++++++++++
 6 files changed, 209 insertions(+), 14 deletions(-)

diff --git a/core/packages/gax/src/clientInterface.ts b/core/packages/gax/src/clientInterface.ts
index b9f3bd8b8e9c..b872b795c33c 100644
--- a/core/packages/gax/src/clientInterface.ts
+++ b/core/packages/gax/src/clientInterface.ts
@@ -28,10 +28,19 @@ import {
 import * as longrunning from './longRunningCalls/longrunning';
 import * as operationProtos from '../protos/operations';
 
+/**
+ * The static trace context is information about the Google Cloud client library that is
+ * used to generate telemetry tracing information.
+ */
+export interface StaticTraceContext {
+  gcpClientService?: string;
+  gcpVersion?: string;
+  gcpRepo?: string;
+  gcpArtifact?: string;
+}
+
 export interface ClientOptions
-  extends GrpcClientOptions,
-    GoogleAuthOptions,
-    ClientStubOptions {
+  extends GrpcClientOptions, GoogleAuthOptions, ClientStubOptions {
   libName?: string;
   libVersion?: string;
   clientConfig?: gax.ClientConfig;
@@ -42,6 +51,15 @@ export interface ClientOptions
   // No preference; exception will be thrown if both are set to different values.
   universeDomain?: string;
   universe_domain?: string;
+  /**
+   * Whether to enable telemetry tracing for the client.
+   */
+  enableTelemetryTracing?: boolean;
+  /**
+   * The static trace context is information about the Google Cloud client library that is
+   * used to generate telemetry tracing information.
+   */
+  internalTelemetryInfo?: StaticTraceContext;
 }
 
 export interface Descriptors {
diff --git a/core/packages/gax/src/createApiCall.ts b/core/packages/gax/src/createApiCall.ts
index b3fdee987a6d..ca0e66a9aa1b 100644
--- a/core/packages/gax/src/createApiCall.ts
+++ b/core/packages/gax/src/createApiCall.ts
@@ -34,6 +34,19 @@ import {addTimeoutArg} from './normalCalls/timeout';
 import {StreamingApiCaller} from './streamingCalls/streamingApiCaller';
 import {warn} from './warnings';
 
+/**
+ * Checks if telemetry tracing is enabled
+ * @param settings
+ * @returns true if telemetry tracing is enabled, false otherwise
+ */
+export function checkTelemetryEnabled(settings?: CallSettings): boolean {
+  const tracingEnabled =
+    Boolean(settings?.enableTelemetryTracing) &&
+    process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED === 'true' &&
+    settings?.internalTelemetryInfo !== undefined;
+  return Boolean(tracingEnabled);
+}
+
 /**
  * Converts an rpc call into an API call governed by the settings.
  *
@@ -66,8 +79,7 @@ export function createApiCall(
   const funcPromise = typeof func === 'function' ? Promise.resolve(func) : func;
   // the following apiCaller will be used for all calls of this function...
   const apiCaller = createAPICaller(settings, descriptor);
-
-  return (
+  const invokeCall = (
     request: RequestType,
     callOptions?: CallOptions,
     callback?: APICallback,
@@ -154,7 +166,12 @@ export function createApiCall(
       .then((apiCall: SimpleCallbackFunction) => {
         // After adding retries / timeouts, the call function becomes simpler:
         // it only accepts request and callback.
-        currentApiCaller.call(apiCall, request, thisSettings, ongoingCall);
+        return currentApiCaller.call(
+          apiCall,
+          request,
+          thisSettings,
+          ongoingCall,
+        );
       })
       .catch(err => {
         currentApiCaller.fail(ongoingCall, err);
@@ -164,4 +181,5 @@ export function createApiCall(
     // or to cancel the ongoing call.
     return currentApiCaller.result(ongoingCall);
   };
+  return invokeCall;
 }
diff --git a/core/packages/gax/src/gax.ts b/core/packages/gax/src/gax.ts
index a38152c24290..8b70f5d9b052 100644
--- a/core/packages/gax/src/gax.ts
+++ b/core/packages/gax/src/gax.ts
@@ -25,6 +25,7 @@ import {BundleOptions} from './bundlingCalls/bundleExecutor';
 import {toLowerCamelCase} from './util';
 import {Status} from './status';
 import {RequestType} from './apitypes';
+import type {StaticTraceContext} from './clientInterface';
 
 /**
  * Encapsulates the overridable settings for a particular API call.
@@ -170,6 +171,8 @@ export interface CallOptions {
   longrunning?: BackoffSettings;
   apiName?: string;
   retryRequestOptions?: RetryRequestOptions;
+  enableTelemetryTracing?: boolean;
+  internalTelemetryInfo?: StaticTraceContext;
 }
 
 export class CallSettings {
@@ -186,6 +189,8 @@ export class CallSettings {
   longrunning?: BackoffSettings;
   apiName?: string;
   retryRequestOptions?: RetryRequestOptions;
+  enableTelemetryTracing?: boolean;
+  internalTelemetryInfo?: StaticTraceContext;
 
   /**
    * @param {Object} settings - An object containing parameters of this settings.
@@ -219,6 +224,8 @@ export class CallSettings {
       'longrunning' in settings ? settings.longrunning : undefined;
     this.apiName = settings.apiName ?? undefined;
     this.retryRequestOptions = settings.retryRequestOptions;
+    this.enableTelemetryTracing = settings.enableTelemetryTracing;
+    this.internalTelemetryInfo = settings.internalTelemetryInfo;
   }
 
   /**
@@ -242,6 +249,8 @@ export class CallSettings {
     let longrunning = this.longrunning;
     let apiName = this.apiName;
     let retryRequestOptions = this.retryRequestOptions;
+    let enableTelemetryTracing = this.enableTelemetryTracing;
+    let internalTelemetryInfo = this.internalTelemetryInfo;
 
     // If the user provides a timeout to the method, that timeout value will be used
     // to override the backoff settings.
@@ -297,6 +306,12 @@ export class CallSettings {
     if ('retryRequestOptions' in options) {
       retryRequestOptions = options.retryRequestOptions;
     }
+    if ('enableTelemetryTracing' in options) {
+      enableTelemetryTracing = options.enableTelemetryTracing;
+    }
+    if ('internalTelemetryInfo' in options) {
+      internalTelemetryInfo = options.internalTelemetryInfo;
+    }
 
     return new CallSettings({
       timeout,
@@ -309,6 +324,8 @@ export class CallSettings {
       isBundling,
       apiName,
       retryRequestOptions,
+      enableTelemetryTracing,
+      internalTelemetryInfo,
     });
   }
 }
diff --git a/core/packages/gax/src/index.ts b/core/packages/gax/src/index.ts
index d9c82f34530e..710d90e42a71 100644
--- a/core/packages/gax/src/index.ts
+++ b/core/packages/gax/src/index.ts
@@ -29,7 +29,7 @@ export * as loggingUtils from 'google-logging-utils';
 
 export {grpc};
 export {CancellablePromise, OngoingCall} from './call';
-export {createApiCall} from './createApiCall';
+export {createApiCall, checkTelemetryEnabled} from './createApiCall';
 export {
   BundleDescriptor,
   LongrunningDescriptor,
diff --git a/core/packages/gax/test/unit/apiCallable.ts b/core/packages/gax/test/unit/apiCallable.ts
index f341ec12f01f..59bed189bad6 100644
--- a/core/packages/gax/test/unit/apiCallable.ts
+++ b/core/packages/gax/test/unit/apiCallable.ts
@@ -21,6 +21,7 @@ import * as sinon from 'sinon';
 
 import {RequestType} from '../../src/apitypes';
 import * as gax from '../../src/gax';
+import {checkTelemetryEnabled} from '../../src/createApiCall';
 import {GoogleError} from '../../src/googleError';
 import * as utils from './utils';
 import * as retries from '../../src/normalCalls/retries';
@@ -329,6 +330,75 @@ describe('createApiCall', () => {
       );
     }
   });
+
+  describe('in regards to OpenTelemetry Tracing', () => {
+    afterEach(() => {
+      delete process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED;
+    });
+
+    describe('checkTelemetryEnabled', () => {
+      const mockSettings = new gax.CallSettings({
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: {
+          gcpClientService: 'test.googleapis.com',
+        },
+      });
+
+      it('returns true when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED=true and settings are configured', () => {
+        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+        assert.strictEqual(checkTelemetryEnabled(mockSettings), true);
+      });
+
+      it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not set', () => {
+        assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
+      });
+
+      it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not "true"', () => {
+        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'false';
+        assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
+      });
+
+      it('returns false when enableTelemetryTracing is not set on settings', () => {
+        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+        const noTracingSettings = new gax.CallSettings({
+          internalTelemetryInfo: {
+            gcpClientService: 'test.googleapis.com',
+          },
+        });
+        assert.strictEqual(checkTelemetryEnabled(noTracingSettings), false);
+      });
+
+      it('returns false when internalTelemetryInfo is not set on settings', () => {
+        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+        const noInfoSettings = new gax.CallSettings({
+          enableTelemetryTracing: true,
+        });
+        assert.strictEqual(checkTelemetryEnabled(noInfoSettings), false);
+      });
+
+      it('returns false when settings is undefined', () => {
+        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+        assert.strictEqual(checkTelemetryEnabled(undefined), false);
+      });
+    });
+
+    it('creates an api call when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED and CallSettings field is set', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+      const mockCallSettings = {
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: {
+          gcpClientService: 'test.googleapis.com',
+        },
+      };
+      const apiCall = createApiCall(() => {}, {settings: mockCallSettings});
+      assert.strictEqual(typeof apiCall, 'function');
+    });
+
+    it('creates an api call when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not set', () => {
+      const apiCall = createApiCall(() => {});
+      assert.strictEqual(typeof apiCall, 'function');
+    });
+  });
 });
 
 describe('Promise', () => {
@@ -350,7 +420,7 @@ describe('Promise', () => {
         assert.ok(Array.isArray(response));
         assert.strictEqual(response[0], 42);
         assert.ok(deadlineArg);
-        done();
+        return done();
       })
       .catch(done);
   });
@@ -380,7 +450,7 @@ describe('Promise', () => {
     const promise = (apiCall as any)(null);
     promise
       .then(() => {
-        done(new Error('should not reach'));
+        return done(new Error('should not reach'));
       })
       .catch((err: {code: number}) => {
         assert(err instanceof GoogleError);
@@ -420,7 +490,7 @@ describe('Promise', () => {
     const promise = (apiCall as any)(null);
     promise
       .then(() => {
-        done(new Error('should not reach'));
+        return done(new Error('should not reach'));
       })
       .catch(() => {
         assert(callCount < 4);
@@ -509,7 +579,7 @@ describe('retryable', () => {
         assert.strictEqual(resp[0], 1729);
         assert.strictEqual(toAttempt, 0);
         assert.ok(deadlineArg);
-        done();
+        return done();
       })
       .catch(done);
   });
@@ -534,7 +604,7 @@ describe('retryable', () => {
     const promise = apiCall({}, undefined);
     promise
       .then(() => {
-        done(new Error('should not reach'));
+        return done(new Error('should not reach'));
       })
       .catch((err: Error) => {
         assert(err instanceof Error);
@@ -795,6 +865,7 @@ describe('retryable', () => {
       })
       .then(() => {
         mockBuilder.verify();
+        return;
       });
   });
 
@@ -821,9 +892,9 @@ describe('retryable', () => {
       try {
         assert.strictEqual(gotHeaders.h1, 'val1');
         assert.strictEqual(gotHeaders.h2, 'val2');
-        done();
+        return done();
       } catch (err) {
-        done(err);
+        return done(err);
       }
     });
   });
diff --git a/core/packages/gax/test/unit/gax.ts b/core/packages/gax/test/unit/gax.ts
index 214b3d07d46f..74271d8df16a 100644
--- a/core/packages/gax/test/unit/gax.ts
+++ b/core/packages/gax/test/unit/gax.ts
@@ -198,4 +198,75 @@ describe('gax construct settings', () => {
     assert.strictEqual(backoff.maxRetryDelayMillis, 1000);
     assert.deepStrictEqual(settings.retry.retryCodes, [RETRY_DICT.code_c]);
   });
+
+  describe('CallSettings telemetry fields', () => {
+    const mockTelemetryInfo = {
+      gcpClientService: 'test.googleapis.com',
+      gcpVersion: '1.0.0',
+      gcpRepo: 'googleapis/google-cloud-node',
+      gcpArtifact: 'google-cloud-test',
+    };
+
+    it('defaults enableTelemetryTracing and internalTelemetryInfo to undefined', () => {
+      const settings = new gax.CallSettings();
+      assert.strictEqual(settings.enableTelemetryTracing, undefined);
+      assert.strictEqual(settings.internalTelemetryInfo, undefined);
+    });
+
+    it('initializes enableTelemetryTracing and internalTelemetryInfo', () => {
+      const settings = new gax.CallSettings({
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: mockTelemetryInfo,
+      });
+      assert.strictEqual(settings.enableTelemetryTracing, true);
+      assert.deepStrictEqual(settings.internalTelemetryInfo, mockTelemetryInfo);
+    });
+
+    it('merges enableTelemetryTracing and internalTelemetryInfo', () => {
+      const settings = new gax.CallSettings({
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: mockTelemetryInfo,
+      });
+      const merged = settings.merge({
+        enableTelemetryTracing: false,
+      });
+      assert.strictEqual(merged.enableTelemetryTracing, false);
+      assert.deepStrictEqual(merged.internalTelemetryInfo, mockTelemetryInfo);
+    });
+
+    it('merges with new internalTelemetryInfo', () => {
+      const settings = new gax.CallSettings({
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: mockTelemetryInfo,
+      });
+      const newTelemetryInfo = {
+        gcpClientService: 'updated.googleapis.com',
+      };
+      const merged = settings.merge({
+        internalTelemetryInfo: newTelemetryInfo,
+      });
+      assert.strictEqual(merged.enableTelemetryTracing, true);
+      assert.deepStrictEqual(merged.internalTelemetryInfo, newTelemetryInfo);
+    });
+
+    it('copies telemetry fields when merging with null/empty options', () => {
+      const settings = new gax.CallSettings({
+        enableTelemetryTracing: true,
+        internalTelemetryInfo: mockTelemetryInfo,
+      });
+      const mergedNull = settings.merge(null);
+      assert.strictEqual(mergedNull.enableTelemetryTracing, true);
+      assert.deepStrictEqual(
+        mergedNull.internalTelemetryInfo,
+        mockTelemetryInfo,
+      );
+
+      const mergedEmpty = settings.merge({});
+      assert.strictEqual(mergedEmpty.enableTelemetryTracing, true);
+      assert.deepStrictEqual(
+        mergedEmpty.internalTelemetryInfo,
+        mockTelemetryInfo,
+      );
+    });
+  });
 });

From f6932dc93915679b481be92a93887d0af66580ab Mon Sep 17 00:00:00 2001
From: Shivanee Persaud <shivaneep@google.com>
Date: Tue, 25 Aug 2026 12:58:29 -0700
Subject: [PATCH 2/5] refactor(gax): remove internalTelemetryInfo from
 ClientOptions

---
 core/packages/gax/src/clientInterface.ts | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/core/packages/gax/src/clientInterface.ts b/core/packages/gax/src/clientInterface.ts
index b872b795c33c..69517812f25c 100644
--- a/core/packages/gax/src/clientInterface.ts
+++ b/core/packages/gax/src/clientInterface.ts
@@ -55,11 +55,6 @@ export interface ClientOptions
    * Whether to enable telemetry tracing for the client.
    */
   enableTelemetryTracing?: boolean;
-  /**
-   * The static trace context is information about the Google Cloud client library that is
-   * used to generate telemetry tracing information.
-   */
-  internalTelemetryInfo?: StaticTraceContext;
 }
 
 export interface Descriptors {

From 01dca2b62d9593392f6d79a6eaa83135f583bcc7 Mon Sep 17 00:00:00 2001
From: Shivanee Persaud <shivaneep@google.com>
Date: Tue, 25 Aug 2026 13:13:07 -0700
Subject: [PATCH 3/5] refactor(gax): move checkTelemetryEnabled to util.ts and
 export it

---
 core/packages/gax/src/createApiCall.ts     | 13 ------
 core/packages/gax/src/index.ts             |  9 +++-
 core/packages/gax/src/util.ts              | 15 ++++++
 core/packages/gax/test/unit/apiCallable.ts | 47 -------------------
 core/packages/gax/test/unit/util.ts        | 54 +++++++++++++++++++++-
 5 files changed, 75 insertions(+), 63 deletions(-)

diff --git a/core/packages/gax/src/createApiCall.ts b/core/packages/gax/src/createApiCall.ts
index ca0e66a9aa1b..e161879d5c93 100644
--- a/core/packages/gax/src/createApiCall.ts
+++ b/core/packages/gax/src/createApiCall.ts
@@ -34,19 +34,6 @@ import {addTimeoutArg} from './normalCalls/timeout';
 import {StreamingApiCaller} from './streamingCalls/streamingApiCaller';
 import {warn} from './warnings';
 
-/**
- * Checks if telemetry tracing is enabled
- * @param settings
- * @returns true if telemetry tracing is enabled, false otherwise
- */
-export function checkTelemetryEnabled(settings?: CallSettings): boolean {
-  const tracingEnabled =
-    Boolean(settings?.enableTelemetryTracing) &&
-    process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED === 'true' &&
-    settings?.internalTelemetryInfo !== undefined;
-  return Boolean(tracingEnabled);
-}
-
 /**
  * Converts an rpc call into an API call governed by the settings.
  *
diff --git a/core/packages/gax/src/index.ts b/core/packages/gax/src/index.ts
index 710d90e42a71..cb86a17ba3ae 100644
--- a/core/packages/gax/src/index.ts
+++ b/core/packages/gax/src/index.ts
@@ -29,7 +29,7 @@ export * as loggingUtils from 'google-logging-utils';
 
 export {grpc};
 export {CancellablePromise, OngoingCall} from './call';
-export {createApiCall, checkTelemetryEnabled} from './createApiCall';
+export {createApiCall} from './createApiCall';
 export {
   BundleDescriptor,
   LongrunningDescriptor,
@@ -113,7 +113,12 @@ export {
   PaginationResponse,
 } from './clientInterface';
 
-export {makeUUID, decodeAnyProtosInArray, decodeProtobufAny} from './util';
+export {
+  makeUUID,
+  decodeAnyProtosInArray,
+  decodeProtobufAny,
+  checkTelemetryEnabled,
+} from './util';
 
 export {ServiceError, ChannelCredentials} from '@grpc/grpc-js';
 export {warn} from './warnings';
diff --git a/core/packages/gax/src/util.ts b/core/packages/gax/src/util.ts
index 16f32f56eb75..180209a8e988 100644
--- a/core/packages/gax/src/util.ts
+++ b/core/packages/gax/src/util.ts
@@ -14,12 +14,27 @@
  * limitations under the License.
  */
 
+import {CallSettings} from './gax';
+
 const PROTO_TYPE_PREFIX = 'type.googleapis.com/';
 const NUM_OF_PARTS_IN_PROTO_TYPE_NAME = 2;
 
 const randomUUID = () =>
   globalThis.crypto?.randomUUID() || require('crypto').randomUUID();
 
+/**
+ * Checks if telemetry tracing is enabled
+ * @param settings
+ * @returns true if telemetry tracing is enabled, false otherwise
+ */
+export function checkTelemetryEnabled(settings?: CallSettings): boolean {
+  const tracingEnabled =
+    Boolean(settings?.enableTelemetryTracing) &&
+    process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED === 'true' &&
+    settings?.internalTelemetryInfo !== undefined;
+  return Boolean(tracingEnabled);
+}
+
 function words(str: string, normalize = false) {
   if (normalize) {
     // strings like somethingABCSomething are special case for protobuf.js,
diff --git a/core/packages/gax/test/unit/apiCallable.ts b/core/packages/gax/test/unit/apiCallable.ts
index 59bed189bad6..db2c60abe442 100644
--- a/core/packages/gax/test/unit/apiCallable.ts
+++ b/core/packages/gax/test/unit/apiCallable.ts
@@ -21,7 +21,6 @@ import * as sinon from 'sinon';
 
 import {RequestType} from '../../src/apitypes';
 import * as gax from '../../src/gax';
-import {checkTelemetryEnabled} from '../../src/createApiCall';
 import {GoogleError} from '../../src/googleError';
 import * as utils from './utils';
 import * as retries from '../../src/normalCalls/retries';
@@ -336,52 +335,6 @@ describe('createApiCall', () => {
       delete process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED;
     });
 
-    describe('checkTelemetryEnabled', () => {
-      const mockSettings = new gax.CallSettings({
-        enableTelemetryTracing: true,
-        internalTelemetryInfo: {
-          gcpClientService: 'test.googleapis.com',
-        },
-      });
-
-      it('returns true when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED=true and settings are configured', () => {
-        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
-        assert.strictEqual(checkTelemetryEnabled(mockSettings), true);
-      });
-
-      it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not set', () => {
-        assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
-      });
-
-      it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not "true"', () => {
-        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'false';
-        assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
-      });
-
-      it('returns false when enableTelemetryTracing is not set on settings', () => {
-        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
-        const noTracingSettings = new gax.CallSettings({
-          internalTelemetryInfo: {
-            gcpClientService: 'test.googleapis.com',
-          },
-        });
-        assert.strictEqual(checkTelemetryEnabled(noTracingSettings), false);
-      });
-
-      it('returns false when internalTelemetryInfo is not set on settings', () => {
-        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
-        const noInfoSettings = new gax.CallSettings({
-          enableTelemetryTracing: true,
-        });
-        assert.strictEqual(checkTelemetryEnabled(noInfoSettings), false);
-      });
-
-      it('returns false when settings is undefined', () => {
-        process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
-        assert.strictEqual(checkTelemetryEnabled(undefined), false);
-      });
-    });
-
     it('creates an api call when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED and CallSettings field is set', () => {
       process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
       const mockCallSettings = {
diff --git a/core/packages/gax/test/unit/util.ts b/core/packages/gax/test/unit/util.ts
index 2a716fa27113..fffaf7b69509 100644
--- a/core/packages/gax/test/unit/util.ts
+++ b/core/packages/gax/test/unit/util.ts
@@ -15,7 +15,7 @@
  */
 
 import assert from 'assert';
-import {describe, it} from 'mocha';
+import {afterEach, describe, it} from 'mocha';
 import {
   toCamelCase as snakeToCamelCase,
   camelToSnakeCase,
@@ -24,7 +24,9 @@ import {
   getProtoNameFromFullName,
   decodeProtobufAny,
   decodeAnyProtosInArray,
+  checkTelemetryEnabled,
 } from '../../src/util';
+import {CallSettings} from '../../src/gax';
 import * as protobuf from 'protobufjs';
 import protosJson from '../../protos/status.json';
 
@@ -196,4 +198,54 @@ describe('util.ts', () => {
       JSON.stringify([{reason: 'SERVICE_DISABLED'}]),
     );
   });
+
+  describe('checkTelemetryEnabled', () => {
+    afterEach(() => {
+      delete process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED;
+    });
+
+    const mockSettings = new CallSettings({
+      enableTelemetryTracing: true,
+      internalTelemetryInfo: {
+        gcpClientService: 'test.googleapis.com',
+      },
+    });
+
+    it('returns true when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED=true and settings are configured', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+      assert.strictEqual(checkTelemetryEnabled(mockSettings), true);
+    });
+
+    it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not set', () => {
+      assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
+    });
+
+    it('returns false when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED is not "true"', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'false';
+      assert.strictEqual(checkTelemetryEnabled(mockSettings), false);
+    });
+
+    it('returns false when enableTelemetryTracing is not set on settings', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+      const noTracingSettings = new CallSettings({
+        internalTelemetryInfo: {
+          gcpClientService: 'test.googleapis.com',
+        },
+      });
+      assert.strictEqual(checkTelemetryEnabled(noTracingSettings), false);
+    });
+
+    it('returns false when internalTelemetryInfo is not set on settings', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+      const noInfoSettings = new CallSettings({
+        enableTelemetryTracing: true,
+      });
+      assert.strictEqual(checkTelemetryEnabled(noInfoSettings), false);
+    });
+
+    it('returns false when settings is undefined', () => {
+      process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
+      assert.strictEqual(checkTelemetryEnabled(undefined), false);
+    });
+  });
 });

From cdd934ff099301e12df4ed24624a439c39b9cb91 Mon Sep 17 00:00:00 2001
From: Shivanee Persaud <shivaneep@google.com>
Date: Tue, 25 Aug 2026 15:36:37 -0700
Subject: [PATCH 4/5] refactor(gax): remove internalTelemetryInfo from
 CallSettings and CallOptions

---
 core/packages/gax/src/gax.ts               |  9 -----
 core/packages/gax/src/util.ts              |  2 +-
 core/packages/gax/test/unit/apiCallable.ts | 10 +++--
 core/packages/gax/test/unit/gax.ts         | 44 ++--------------------
 core/packages/gax/test/unit/util.ts        | 12 ++++--
 5 files changed, 19 insertions(+), 58 deletions(-)

diff --git a/core/packages/gax/src/gax.ts b/core/packages/gax/src/gax.ts
index 8b70f5d9b052..33f8d1672d3b 100644
--- a/core/packages/gax/src/gax.ts
+++ b/core/packages/gax/src/gax.ts
@@ -25,7 +25,6 @@ import {BundleOptions} from './bundlingCalls/bundleExecutor';
 import {toLowerCamelCase} from './util';
 import {Status} from './status';
 import {RequestType} from './apitypes';
-import type {StaticTraceContext} from './clientInterface';
 
 /**
  * Encapsulates the overridable settings for a particular API call.
@@ -172,7 +171,6 @@ export interface CallOptions {
   apiName?: string;
   retryRequestOptions?: RetryRequestOptions;
   enableTelemetryTracing?: boolean;
-  internalTelemetryInfo?: StaticTraceContext;
 }
 
 export class CallSettings {
@@ -190,7 +188,6 @@ export class CallSettings {
   apiName?: string;
   retryRequestOptions?: RetryRequestOptions;
   enableTelemetryTracing?: boolean;
-  internalTelemetryInfo?: StaticTraceContext;
 
   /**
    * @param {Object} settings - An object containing parameters of this settings.
@@ -225,7 +222,6 @@ export class CallSettings {
     this.apiName = settings.apiName ?? undefined;
     this.retryRequestOptions = settings.retryRequestOptions;
     this.enableTelemetryTracing = settings.enableTelemetryTracing;
-    this.internalTelemetryInfo = settings.internalTelemetryInfo;
   }
 
   /**
@@ -250,7 +246,6 @@ export class CallSettings {
     let apiName = this.apiName;
     let retryRequestOptions = this.retryRequestOptions;
     let enableTelemetryTracing = this.enableTelemetryTracing;
-    let internalTelemetryInfo = this.internalTelemetryInfo;
 
     // If the user provides a timeout to the method, that timeout value will be used
     // to override the backoff settings.
@@ -309,9 +304,6 @@ export class CallSettings {
     if ('enableTelemetryTracing' in options) {
       enableTelemetryTracing = options.enableTelemetryTracing;
     }
-    if ('internalTelemetryInfo' in options) {
-      internalTelemetryInfo = options.internalTelemetryInfo;
-    }
 
     return new CallSettings({
       timeout,
@@ -325,7 +317,6 @@ export class CallSettings {
       apiName,
       retryRequestOptions,
       enableTelemetryTracing,
-      internalTelemetryInfo,
     });
   }
 }
diff --git a/core/packages/gax/src/util.ts b/core/packages/gax/src/util.ts
index 180209a8e988..de388fe4c834 100644
--- a/core/packages/gax/src/util.ts
+++ b/core/packages/gax/src/util.ts
@@ -31,7 +31,7 @@ export function checkTelemetryEnabled(settings?: CallSettings): boolean {
   const tracingEnabled =
     Boolean(settings?.enableTelemetryTracing) &&
     process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED === 'true' &&
-    settings?.internalTelemetryInfo !== undefined;
+    settings?.otherArgs?.internalTelemetryInfo !== undefined;
   return Boolean(tracingEnabled);
 }
 
diff --git a/core/packages/gax/test/unit/apiCallable.ts b/core/packages/gax/test/unit/apiCallable.ts
index db2c60abe442..f7cfaed41485 100644
--- a/core/packages/gax/test/unit/apiCallable.ts
+++ b/core/packages/gax/test/unit/apiCallable.ts
@@ -337,13 +337,15 @@ describe('createApiCall', () => {
 
     it('creates an api call when GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED and CallSettings field is set', () => {
       process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
-      const mockCallSettings = {
+      const mockCallOptions: gax.CallOptions = {
         enableTelemetryTracing: true,
-        internalTelemetryInfo: {
-          gcpClientService: 'test.googleapis.com',
+        otherArgs: {
+          internalTelemetryInfo: {
+            gcpClientService: 'test.googleapis.com',
+          },
         },
       };
-      const apiCall = createApiCall(() => {}, {settings: mockCallSettings});
+      const apiCall = createApiCall(() => {}, {settings: mockCallOptions});
       assert.strictEqual(typeof apiCall, 'function');
     });
 
diff --git a/core/packages/gax/test/unit/gax.ts b/core/packages/gax/test/unit/gax.ts
index 74271d8df16a..d166ef98c03c 100644
--- a/core/packages/gax/test/unit/gax.ts
+++ b/core/packages/gax/test/unit/gax.ts
@@ -200,73 +200,37 @@ describe('gax construct settings', () => {
   });
 
   describe('CallSettings telemetry fields', () => {
-    const mockTelemetryInfo = {
-      gcpClientService: 'test.googleapis.com',
-      gcpVersion: '1.0.0',
-      gcpRepo: 'googleapis/google-cloud-node',
-      gcpArtifact: 'google-cloud-test',
-    };
-
-    it('defaults enableTelemetryTracing and internalTelemetryInfo to undefined', () => {
+    it('defaults enableTelemetryTracing to undefined', () => {
       const settings = new gax.CallSettings();
       assert.strictEqual(settings.enableTelemetryTracing, undefined);
-      assert.strictEqual(settings.internalTelemetryInfo, undefined);
     });
 
-    it('initializes enableTelemetryTracing and internalTelemetryInfo', () => {
+    it('initializes enableTelemetryTracing', () => {
       const settings = new gax.CallSettings({
         enableTelemetryTracing: true,
-        internalTelemetryInfo: mockTelemetryInfo,
       });
       assert.strictEqual(settings.enableTelemetryTracing, true);
-      assert.deepStrictEqual(settings.internalTelemetryInfo, mockTelemetryInfo);
     });
 
-    it('merges enableTelemetryTracing and internalTelemetryInfo', () => {
+    it('merges enableTelemetryTracing', () => {
       const settings = new gax.CallSettings({
         enableTelemetryTracing: true,
-        internalTelemetryInfo: mockTelemetryInfo,
       });
       const merged = settings.merge({
         enableTelemetryTracing: false,
       });
       assert.strictEqual(merged.enableTelemetryTracing, false);
-      assert.deepStrictEqual(merged.internalTelemetryInfo, mockTelemetryInfo);
-    });
-
-    it('merges with new internalTelemetryInfo', () => {
-      const settings = new gax.CallSettings({
-        enableTelemetryTracing: true,
-        internalTelemetryInfo: mockTelemetryInfo,
-      });
-      const newTelemetryInfo = {
-        gcpClientService: 'updated.googleapis.com',
-      };
-      const merged = settings.merge({
-        internalTelemetryInfo: newTelemetryInfo,
-      });
-      assert.strictEqual(merged.enableTelemetryTracing, true);
-      assert.deepStrictEqual(merged.internalTelemetryInfo, newTelemetryInfo);
     });
 
-    it('copies telemetry fields when merging with null/empty options', () => {
+    it('copies enableTelemetryTracing when merging with null/empty options', () => {
       const settings = new gax.CallSettings({
         enableTelemetryTracing: true,
-        internalTelemetryInfo: mockTelemetryInfo,
       });
       const mergedNull = settings.merge(null);
       assert.strictEqual(mergedNull.enableTelemetryTracing, true);
-      assert.deepStrictEqual(
-        mergedNull.internalTelemetryInfo,
-        mockTelemetryInfo,
-      );
 
       const mergedEmpty = settings.merge({});
       assert.strictEqual(mergedEmpty.enableTelemetryTracing, true);
-      assert.deepStrictEqual(
-        mergedEmpty.internalTelemetryInfo,
-        mockTelemetryInfo,
-      );
     });
   });
 });
diff --git a/core/packages/gax/test/unit/util.ts b/core/packages/gax/test/unit/util.ts
index fffaf7b69509..1eaeb76c7763 100644
--- a/core/packages/gax/test/unit/util.ts
+++ b/core/packages/gax/test/unit/util.ts
@@ -206,8 +206,10 @@ describe('util.ts', () => {
 
     const mockSettings = new CallSettings({
       enableTelemetryTracing: true,
-      internalTelemetryInfo: {
-        gcpClientService: 'test.googleapis.com',
+      otherArgs: {
+        internalTelemetryInfo: {
+          gcpClientService: 'test.googleapis.com',
+        },
       },
     });
 
@@ -228,8 +230,10 @@ describe('util.ts', () => {
     it('returns false when enableTelemetryTracing is not set on settings', () => {
       process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED = 'true';
       const noTracingSettings = new CallSettings({
-        internalTelemetryInfo: {
-          gcpClientService: 'test.googleapis.com',
+        otherArgs: {
+          internalTelemetryInfo: {
+            gcpClientService: 'test.googleapis.com',
+          },
         },
       });
       assert.strictEqual(checkTelemetryEnabled(noTracingSettings), false);

From bac525043eb131355ac46486dcae57d08c728898 Mon Sep 17 00:00:00 2001
From: Shivanee Persaud <shivaneep@google.com>
Date: Tue, 25 Aug 2026 15:53:52 -0700
Subject: [PATCH 5/5] refactor(gax): move StaticTraceContext to util.ts

---
 core/packages/gax/src/clientInterface.ts | 11 -----------
 core/packages/gax/src/index.ts           |  1 +
 core/packages/gax/src/util.ts            | 11 +++++++++++
 core/packages/gax/test/unit/exports.ts   |  3 +++
 core/packages/gax/test/unit/util.ts      | 12 +++++++++---
 5 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/core/packages/gax/src/clientInterface.ts b/core/packages/gax/src/clientInterface.ts
index 69517812f25c..bf4571d62689 100644
--- a/core/packages/gax/src/clientInterface.ts
+++ b/core/packages/gax/src/clientInterface.ts
@@ -28,17 +28,6 @@ import {
 import * as longrunning from './longRunningCalls/longrunning';
 import * as operationProtos from '../protos/operations';
 
-/**
- * The static trace context is information about the Google Cloud client library that is
- * used to generate telemetry tracing information.
- */
-export interface StaticTraceContext {
-  gcpClientService?: string;
-  gcpVersion?: string;
-  gcpRepo?: string;
-  gcpArtifact?: string;
-}
-
 export interface ClientOptions
   extends GrpcClientOptions, GoogleAuthOptions, ClientStubOptions {
   libName?: string;
diff --git a/core/packages/gax/src/index.ts b/core/packages/gax/src/index.ts
index cb86a17ba3ae..55c133933787 100644
--- a/core/packages/gax/src/index.ts
+++ b/core/packages/gax/src/index.ts
@@ -118,6 +118,7 @@ export {
   decodeAnyProtosInArray,
   decodeProtobufAny,
   checkTelemetryEnabled,
+  StaticTraceContext,
 } from './util';
 
 export {ServiceError, ChannelCredentials} from '@grpc/grpc-js';
diff --git a/core/packages/gax/src/util.ts b/core/packages/gax/src/util.ts
index de388fe4c834..0492a4321c24 100644
--- a/core/packages/gax/src/util.ts
+++ b/core/packages/gax/src/util.ts
@@ -22,6 +22,17 @@ const NUM_OF_PARTS_IN_PROTO_TYPE_NAME = 2;
 const randomUUID = () =>
   globalThis.crypto?.randomUUID() || require('crypto').randomUUID();
 
+/**
+ * The static trace context is information about the Google Cloud client library that is
+ * used to generate telemetry tracing information.
+ */
+export interface StaticTraceContext {
+  gcpClientService?: string;
+  gcpVersion?: string;
+  gcpRepo?: string;
+  gcpArtifact?: string;
+}
+
 /**
  * Checks if telemetry tracing is enabled
  * @param settings
diff --git a/core/packages/gax/test/unit/exports.ts b/core/packages/gax/test/unit/exports.ts
index 8132209b46d8..fefa004f9fd4 100644
--- a/core/packages/gax/test/unit/exports.ts
+++ b/core/packages/gax/test/unit/exports.ts
@@ -62,6 +62,9 @@ describe('exports', () => {
     it('exports protobufMinimal', () => {
       assert(typeof index.protobufMinimal === 'object');
     });
+    it('exports checkTelemetryEnabled', () => {
+      assert(typeof index.checkTelemetryEnabled === 'function');
+    });
   });
 
   describe('fallback', () => {
diff --git a/core/packages/gax/test/unit/util.ts b/core/packages/gax/test/unit/util.ts
index 1eaeb76c7763..85be595496b6 100644
--- a/core/packages/gax/test/unit/util.ts
+++ b/core/packages/gax/test/unit/util.ts
@@ -25,6 +25,7 @@ import {
   decodeProtobufAny,
   decodeAnyProtosInArray,
   checkTelemetryEnabled,
+  StaticTraceContext,
 } from '../../src/util';
 import {CallSettings} from '../../src/gax';
 import * as protobuf from 'protobufjs';
@@ -204,12 +205,17 @@ describe('util.ts', () => {
       delete process.env.GOOGLE_SDK_NODE_EXPERIMENTAL_O11Y_ENABLED;
     });
 
+    const mockTelemetryInfo: StaticTraceContext = {
+      gcpClientService: 'test.googleapis.com',
+      gcpVersion: '1.0.0',
+      gcpRepo: 'googleapis/google-cloud-node',
+      gcpArtifact: 'google-cloud-test',
+    };
+
     const mockSettings = new CallSettings({
       enableTelemetryTracing: true,
       otherArgs: {
-        internalTelemetryInfo: {
-          gcpClientService: 'test.googleapis.com',
-        },
+        internalTelemetryInfo: mockTelemetryInfo,
       },
     });