fix(llms): use configured fetch for Vertex ADC refreshes (#12981) (#12991)

sdk/packages/llms/src/providers/vendors/vertex.test.ts

@@ -51,9 +51,14 @@ describe("createVertexProviderModule", () => {
 				project: "test-project",
 				location: "global",
 				apiKey: undefined,
-				googleAuthOptions: {
+				googleAuthOptions: expect.objectContaining({
 					projectId: "test-project",
-				},
+					clientOptions: {
+						transporterOptions: {
+							fetchImplementation: globalThis.fetch,
+						},
+					},
+				}),
 				fetch: expect.any(Function),
 			}),
 		);
@@ -77,9 +82,9 @@ describe("createVertexProviderModule", () => {
 			expect.objectContaining({
 				project: "nested-project",
 				location: "europe-west4",
-				googleAuthOptions: {
+				googleAuthOptions: expect.objectContaining({
 					projectId: "nested-project",
-				},
+				}),
 			}),
 		);
 	});
@@ -116,10 +121,46 @@ describe("createVertexProviderModule", () => {
 			expect.objectContaining({
 				project: "test-project",
 				location: "us-east5",
+				googleAuthOptions: expect.objectContaining({
+					projectId: "test-project",
+					clientOptions: {
+						transporterOptions: {
+							fetchImplementation: globalThis.fetch,
+						},
+					},
+				}),
 			}),
 		);
 		expect(createVertexMock).not.toHaveBeenCalled();
 	});
+
+	it("passes a configured fetch to Vertex requests and the ADC refresh transport", async () => {
+		const customFetch = vi.fn() as unknown as typeof fetch;
+
+		await createVertexProviderModule(
+			config({
+				fetch: customFetch,
+				options: {
+					project: "test-project",
+					location: "global",
+				},
+			}),
+			context("claude-sonnet-4-5@20250929"),
+		);
+
+		expect(createVertexAnthropicMock).toHaveBeenCalledWith(
+			expect.objectContaining({
+				fetch: customFetch,
+				googleAuthOptions: expect.objectContaining({
+					clientOptions: {
+						transporterOptions: {
+							fetchImplementation: customFetch,
+						},
+					},
+				}),
+			}),
+		);
+	});
 });
 
 function config(

sdk/packages/llms/src/providers/vendors/vertex.ts

@@ -8,6 +8,25 @@ import { ensureFetch, resolveApiKey } from "../http";
 import { isClaudeModelId } from "../model-facts";
 import type { ProviderFactoryResult } from "./types";
 
+type VertexProviderSettings = NonNullable<Parameters<typeof createVertex>[0]>;
+type VertexGoogleAuthOptions = NonNullable<
+	VertexProviderSettings["googleAuthOptions"]
+>;
+
+function createGoogleAuthOptions(
+	projectId: string | undefined,
+	fetchImplementation: typeof fetch,
+): VertexGoogleAuthOptions {
+	return {
+		...(projectId ? { projectId } : {}),
+		clientOptions: {
+			transporterOptions: {
+				fetchImplementation,
+			},
+		},
+	};
+}
+
 function readStringOption(
 	options: Record<string, unknown> | undefined,
 	key: string,
@@ -49,11 +68,13 @@ export async function createVertexProviderModule(
 		"us-central1";
 	const googleAuthProjectId = project || undefined;
 	const fetch = ensureFetch(config.fetch);
+	const googleAuthOptions = createGoogleAuthOptions(googleAuthProjectId, fetch);
 
 	if (isClaudeModelId(context.model.id)) {
 		const provider = createVertexAnthropic({
 			project,
 			location,
+			googleAuthOptions,
 			baseURL: config.baseUrl,
 			headers: config.headers,
 			fetch,
@@ -65,11 +86,7 @@ export async function createVertexProviderModule(
 		project,
 		location,
 		apiKey: googleAuthProjectId ? undefined : await resolveApiKey(config),
-		googleAuthOptions: googleAuthProjectId
-			? {
-					projectId: googleAuthProjectId,
-				}
-			: undefined,
+		googleAuthOptions: googleAuthProjectId ? googleAuthOptions : undefined,
 		baseURL: config.baseUrl,
 		headers: config.headers,
 		fetch,